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Sample records for calanoid copepod acartia

  1. Recirculating aquaculture system for high density production of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Vu, Minh Thi Thuy; Øie, Gunvor; Reinertsen, Helge

    The calanoid copepod Acartia tonsa (Dana) is one of the most promising copepod species for marine larviculture. This species has a wide tolerance to temperature and salinity, small size, can produce resting eggs. All their nauplii, copepodites and adults can be use as excellent feeds for marine f...

  2. Influence of algal diet on feeding and egg-production of the calanoid copepod Acartia tonsa Dana

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Jensen, Johanne

    1990-01-01

    Threshold concentration, retention efficiency and egg-production in the calanoid copepod Acartia tonsa Dana were examined using the algal species Isochrysis galbana clone T-iso, Dunalietta tertiolecta Butcher, Rhodomonas baltica Karsten, Ditylum brightwellii Grunow and Thalassiosira weissflogii...

  3. DMSP-consuming bacteria associated with the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Tang, K.W.; Visscher, P.T.; Dam, H.G.

    2001-01-01

    DMSP-consuming bacteria (DCB) were recovered from the body and fecal pellets of the copepod Acartia tonsa (Dana). The most probable number of DCB associated with starved A. tonsa was 9.2 X 10(2) cells copepod(-1). The abundance of DCB recovered from the copepod body increased to 1.6-2.8 X 10(4) a...... Elsevier Science B.V. All rights reserved....

  4. Toxicity of nickel in the marine calanoid copepod Acartia tonsa: Nickel chloride versus nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, C. [Istituto per la Protezione e Ricerca Ambientale ISPRA-STS Livorno, Piazzale dei marmi 12, 57123 Livorno (Italy); Academic Centre for Innovation and Development in the Food Industry (CAISIAL), Università degli Studi di Napoli Federico II, 80055 Portici (Italy); Vitiello, V. [Istituto per la Protezione e Ricerca Ambientale ISPRA-STS Livorno, Piazzale dei marmi 12, 57123 Livorno (Italy); Casals, E. [Institut Català de Nanotecnologia, Campus de la Universitat Autònoma de Barcelone, 08193 Bellaterra (Spain); Puntes, V.F. [Institut Català de Nanotecnologia, Campus de la Universitat Autònoma de Barcelone, 08193 Bellaterra (Spain); Institut Català de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, 08010 Barcelona (Spain); Iamunno, F. [Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli (Italy); Pellegrini, D. [Istituto per la Protezione e Ricerca Ambientale ISPRA-STS Livorno, Piazzale dei marmi 12, 57123 Livorno (Italy); Changwen, W. [Zhejiang Ocean University, 1 Rd. South Haida, Lincheng New Area, Dinghai District Zhoushan City, 316022 (China); Benvenuto, G. [Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli (Italy); Buttino, I., E-mail: isabella.buttino@isprambiente.it [Istituto per la Protezione e Ricerca Ambientale ISPRA-STS Livorno, Piazzale dei marmi 12, 57123 Livorno (Italy)

    2016-01-15

    Highlights: • Acartia tonsa copepod is more sensitive to NiCl{sub 2} than to nickel nanoparticles. • At the tested concentration egg production was not affected by both form of nickel. • Egg viability is the most sensitive end-point for both form of nickel. • Nickel dissolved in seawater increased with nanoparticle concentration. • Acartia tonsa adults were able to ingest nanoparticles. - Abstract: Nickel compounds are widely used in industries and have been massively introduced in the environment in different chemical forms. Here we report the effect of two different chemical forms of nickel, NiCl{sub 2} and nickel nanoparticles (NiNPs), on the reproduction of the marine calanoid copepod Acartia tonsa. The behavior of nickel nanoparticles was analyzed with different techniques and with two protocols. In the “sonicated experiment” (SON) NiNP solution was sonicated while in the “non-sonicated experiment” (NON-SON) the solution was vigorously shaken by hand. Final nominal concentrations of 5, 10 and 50 mg L{sup −1} and 1, 5 and 10 mg L{sup −1} NiNPs were used for the acute and semichronic tests, respectively. Nanoparticle size did not change over time except for the highest concentration of 50 mg L{sup −1} NiNPs, in which the diameter increased up to 843 nm after 48 h. The concentration of Ni dissolved in the water increased with NP concentration and was similar for SON and NON-SON solutions. Our results indicate that sonication does not modify toxicity for the copepod A. tonsa. Mean EC{sub 50} values were similar for NON-SON (20.2 mg L{sup −1}) and SON experiments (22.14 mg L{sup −1}) in the acute test. Similarly, no differences occurred between the two different protocols in the semichronic test, with an EC{sub 50} of 7.45 mg L{sup −1} and 6.97 mg L{sup −1} for NON-SON and SON experiments, respectively. Acute and semichronic tests, conducted exposing A. tonsa embryos to NiCl{sub 2} concentrations from 0.025 to 0.63 mg L{sup −1

  5. Resting egg production induced by food limitation in the calanoid copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Hansen, Benni W.; Kiørboe, Thomas

    2011-01-01

    Three populations of the copepod Acartia tonsa, two from the Baltic Sea and one from the U.S. East Coast, were compared for resting egg production at conditions of saturating and limiting food availability. All three populations produced eggs that hatched within 72 h when incubated at 17°C...... (subitaneous eggs), but the two Baltic populations in addition produced eggs that hatched at a much slower rate, in the course of a month (delayed hatching eggs [DHE]). Such eggs were not produced by the U.S. population. The fraction of DHE increased when food was limiting. Females from a Baltic population...... that were incubated individually all produced subitaneous eggs, but about half the females consistently also produced DHE. Cold storage that mimicked boreal winter conditions synchronized the hatching of DHE after extended storage, indicating that spring hatching of DHE might seed the water column...

  6. Recent advances within intensive Recirculated Aquaculture System cultivation of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Højgaard, Jacob Kring; Drillet, Guillaume;

    2014-01-01

    Danish aquaculture has within recent years focused upon rearing of new marine fish species. A major challenge for rearing of marine fish species is relevant diets for their fish larvae. Copepods and their larvae stage “nauplii” are well documented as the ideal live feed for a variety of marine...... and the nauplii can be feed to marine fish larvae. A restriction is that copepod cultures for producing eggs are after 30 years of research still not stable and in large enough scale for bulk production of eggs. Recently a unique copepod Recirculated Aquaculture System (RAS) at Roskilde University (Denmark......) was constructed as a part of the IMPAQ project “IMProvement of AQuaculture high quality fish fry production”. We present recent advance within RAS culture for copepods, and lesson learned from rearing the specie. Further we present physical and biological culture restrictions in terms of water quality (NH3...

  7. Comparative oxygen consumption rates of subitaneous and delayed hatching eggs of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume

    2013-01-01

    Life history strategies can be adaptations to existence in e.g. unstable environments. Under stressful environmental conditions mobile species tend to migrate to more suitable places, but migration in time by dormancy is another durable strategy. More than 50 species of calanoid copepods can...... history trait allowing the spread of hatching over a period of time (a month or two), increasing the likelihood that some offspring encounter suitable environmental conditions and can contribute to the pelagic population of neritic calanoids in environmental fluctuating environments....

  8. Resting eggs in a key player Calanoid copepod in coastal areas. The case of Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Hansen, Benni Winding

    results of 7 years of experimental work which allowed us to understand better the capacity of A. tonsa to produce resting eggs. A.tonsa has a double resting strategy, part of it is due to the capacity of the subitaneous eggs to switch to quiescence under unfavorable environmental conditions which allows......  Acartia tonsa is an invasive copepod of the European coastal waters, first described in France in 1926, it was found later in most of the European coastal areas. These invasions are believed to come from transport of resting eggs in ships ballast water. In this presentation, I will show the main...... the eggs to wait partially optimum conditions to hatch. Also some population of A. tonsa are capable of producing real diapauses eggs (or delayed hatching eggs) which are developed as a single winter based strategy and have to endure a refractory phase before hatching. Our recent findings show that food...

  9. Tolerance of un-ionized ammonia in live feed cultures of the calanoid copepod Acartia tonsa Dana

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Andersen, Claus V. B.; Schjelde, Johannes;

    2015-01-01

    No Observed Effect Concentrations (NOEC) and Lowest Observed Effect Concentrations (LOEC), which provides safety levels before cultures are affected. This study investigates the tolerance of Acartia tonsa nauplii and adults to ammonia, using mortality as the endpoint after 24, 48 and 72 h of exposure. Nauplii...

  10. Defecation of dimethylsulfoniopropionate (DMSP) by the copepod Acartia tonsa as functions of ambient food concentration and body DMSP content

    DEFF Research Database (Denmark)

    Tang, K.W.

    2001-01-01

    The dimethylsulfoniopropionate (DMSP) defecation rate of Acartia tonsa (calanoid copepod)feeding on Tetraselmis impellucida (prasinophyte) was correlated with food concentration and copepod body DMSP content. Copepod fecal pellets represent a highly concentrated source of DMSP and thus play an im...... an important role in DMSP flux and microbial processes in the ocean.......The dimethylsulfoniopropionate (DMSP) defecation rate of Acartia tonsa (calanoid copepod)feeding on Tetraselmis impellucida (prasinophyte) was correlated with food concentration and copepod body DMSP content. Copepod fecal pellets represent a highly concentrated source of DMSP and thus play...

  11. Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, Acartia tonsa: a laboratory study

    Science.gov (United States)

    Shayegan, Majid; Esmaeili Fereidouni, Abolghasem; Agh, Naser; Jani Khalili, Khosrow

    2016-07-01

    The effects of salinity on the copepod, Acartia tonsa in terms of daily egg production rate (EPR), hatching success, fecal pellet production rate (FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods (seven consecutive days). Results show EPR was affected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females (long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages (56.7% and 52.2%, respectively) were significantly observed at two salinities of 13 and 20 compared to that at 35 (25%). Total longevity of females was not affected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

  12. Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances

    DEFF Research Database (Denmark)

    Wollenberger, Leah; Breitholtz, M.; Kusk, Kresten Ole;

    2003-01-01

    A nitro musk (musk ketone). and three polycyclic musks (Tonalide(TM), Galaxolide(TM) and Celestolide(TM)) were tested for acute and subchronic effects on a marine crustacean, the calanoid copepod Acartia tonsa. Sublethal effects on A. tonsa larvae were investigated with a rapid and cost effective...... reserved....

  13. A comprehensive and precise quantification of the calanoid copepod Acartia tonsa (Dana) for intensive live feed cultures using an automated ZooImage system

    DEFF Research Database (Denmark)

    Vu, Minh Thi Thuy; Jepsen, Per Meyer; Hansen, Benni Winding

    2014-01-01

    and 6 non-copepod (debris) groups. ZooImage used this training set for automatic discrimination through a random forest algorithm with the general accuracy of 92.8%. The ZooImage showed no significant difference in classifying solitary eggs, or mixed nauplii stages and copepodites compared to personal...

  14. Characterization and analysis of ribosomal proteins in two marine calanoid copepods

    Science.gov (United States)

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Huang, Yousong; Yi, Xiaoyan; Chen, Hongju; Liu, Guangxing; Zhang, Huan

    2016-11-01

    Copepods are among the most abundant and successful metazoans in the marine ecosystem. However, genomic resources related to fundamental cellular processes are still limited in this particular group of crustaceans. Ribosomal proteins are the building blocks of ribosomes, the primary site for protein synthesis. In this study, we characterized and analyzed the cDNAs of cytoplasmic ribosomal proteins (cRPs) of two calanoid copepods, Pseudodiaptomus poplesia and Acartia pacifica. We obtained 79 cRP cDNAs from P. poplesia and 67 from A. pacifica by cDNA library construction/sequencing and rapid amplification of cDNA ends. Analysis of the nucleic acid composition showed that the copepod cRP-encoding genes had higher GC content in the protein-coding regions (CDSs) than in the untranslated regions (UTRs), and single nucleotide repeats (>3 repeats) were common, with "A" repeats being the most frequent, especially in the CDSs. The 3'-UTRs of the cRP genes were significantly longer than the 5'-UTRs. Codon usage analysis showed that the third positions of the codons were dominated by C or G. The deduced amino acid sequences of the cRPs contained high proportions of positively charged residues and had high pI values. This is the first report of a complete set of cRP-encoding genes from copepods. Our results shed light on the characteristics of cRPs in copepods, and provide fundamental data for further studies of protein synthesis in copepods. The copepod cRP information revealed in this study indicates that additional comparisons and analysis should be performed on different taxonomic categories such as orders and families.

  15. Influence of LAS on marine calanoid copepod population dynamics and potential reproduction.

    Science.gov (United States)

    Christoffersen, Kirsten; Hansen, Benni W; Johansson, Liselotte S; Krog, Elisabeth

    2003-05-29

    The toxicity of linear alkyl benzene sulfonate (LAS) to marine invertebrates is well documented under laboratory conditions using single-species tests. It is less known how LAS affects natural populations of aquatic organisms. We hypothesised that LAS was more toxic to the calanoid copepod Acartia sp. under natural conditions than Acartia tonsa under cultured conditions in the laboratory. This hypothesis was checked by a direct comparison of LAS toxicity in single-species and model (mesocosm) studies. The acute and sublethal effects of LAS on the survival and egg production of laboratory reared A. tonsa were examined by standard test, i.e. incubation with LAS without food for 24-72 h. The LC(50) and EC(50) values averaged 1.23 and 0.74 mg l(-1) for survival and egg production, respectively. These values are comparable to previous reports. The effects of LAS on a natural copepod community were also investigated under in situ conditions. A series of seven mesocosms (holding approx. 3 m(3) of seawater each) was established with two mesocosms being controls without LAS and five mesocosms with increasing concentrations of LAS ranging from 0.1 to 6.5 mg l(-1) applied as a single dose. The indigenous copepod community, dominated by Acartia sp. and Centropages sp., responded clearly to LAS concentrations above 0.1 mg l(-1). The calculated no effect value was 0.14 mg LAS l(-1) (95% CI=0.08-1.82 mg LAS l(-1)) for the entire copepod community including all development stages after 24 h exposure. The increased sensitivity under in situ conditions was probably promoted by the suboptimal growth conditions, e.g. no saturated food concentration or inadequate nutritive values of the food. The amount of food expressed as chlorophyll concentration was low (around 2 microg chl. a l(-1)) but was not affected by LAS. It appeared that the naupliar stages of Acartia and Centropages were the least affected by LAS and that new cohorts were able to develop 15 days after the dosing with LAS.

  16. Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances.

    Science.gov (United States)

    Wollenberger, Leah; Breitholtz, Magnus; Ole Kusk, Kresten; Bengtsson, Bengt Erik

    2003-04-15

    A nitro musk (musk ketone) and three polycyclic musks (Tonalide, Galaxolide and Celestolide) were tested for acute and subchronic effects on a marine crustacean, the calanoid copepod Acartia tonsa. Sublethal effects on A. tonsa larvae were investigated with a rapid and cost effective bioassay, which is based on the easily detectable morphological change from the last nauplius to the first copepodite stage during copepod larval development. The inhibition of larval development after 5 days exposure was a very sensitive endpoint, with 5-d-EC(50)-values as low as 0.026 mg/l (Tonalide), 0.059 mg/l (Galaxolide), 0.066 mg/l (musk ketone) and 0.160 mg/l (Celestolide), respectively. These values were generally more than one order of magnitude below the 48-h-LC(50)-values found for adults, which were 0.47 mg/l (Galaxolide), 0.71 mg/l (Celestolide), 1.32 mg/l (musk ketone) and 2.5 mg/l (Tonalide). Since the synthetic musks strongly inhibited larval development in A. tonsa at low nominal concentrations, they should be considered as very toxic. The larval development test with A. tonsa is able to provide important aquatic toxicity data for the evaluation of synthetic musks, for which there is little published ecotoxicological information available regarding Crustacea. It is suggested that subchronic and chronic copepod toxicity tests should be used more frequently for risk assessment of environmental pollutants.

  17. A new large egg type from the marine live feed calanoid copepod Acartia tonsa (Dana) – Perspectives for selective breeding of designer feed for hatcheries

    DEFF Research Database (Denmark)

    Halsen Hammarvold, Stian; Glud, Ronnie N.; Evjemo, Jan Ove

    2015-01-01

    Mass cultivation ofmarine copepods as live feed requires predictable and uniform production of a standard product for the end users, the hatcheries. A previously undescribed large egg type, measuring a mean diameter of 106.5 μm, was characterized and compared to normal eggs (82.3 μm) from a conti....... The next generations' eggswere not as large as the ones they originated from suggesting that the rare large eggs represent a maternal effect. The large size eggs do however pose an interesting selection potential for designing large species-specific live feed products in aquaculture....

  18. Different microbiomes associated with the copepods Acartia tonsa and Temora longicornis from the same marine environment

    DEFF Research Database (Denmark)

    Dorosz, Julia; Castro-Mejia, Josue Leonardo; Hansen, Lars Hestbjerg

    2016-01-01

    Microbiomes of the neritic copepod species Acartia tonsa and Temora longicornis collected in coastal Danish waters were investigated by use of 16S rRNA gene-Amplicon highthroughput sequencing. In contrast to current assumptions and findings, microbiomes of the 2 copepod species from the same envi...

  19. Consequences of acclimation to Microcystis on the selective feeding behavior of the calanoid copepod Eudiaptomus gracilis

    NARCIS (Netherlands)

    Ger, K.A.; Panosso, R.; Lürling, M.F.L.L.W.

    2011-01-01

    We tested the hypothesis that calanoid copepods would adapt to extended periods of Microcystis exposure by increasing selective feeding on alternative food. Copepod (Eudiaptomus gracilis) clearance rates were compared before and after a 5-d acclimation to Microcystis aeruginosa using paired food mix

  20. Effect of 2,4-dihydroxybenzophenone (BP1) on early life-stage development of the marine copepod Acartia tonsa at different temperatures and salinities

    DEFF Research Database (Denmark)

    Kusk, Kresten Ole; Avdolli, Manola; Wollenberger, Leah

    2011-01-01

    Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life-stage devel......Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life......-stage development study. Since developmental endpoints depend on environmental conditions, a preceding study of A. tonsa development was performed at three temperatures, four salinities, four light:dark regimes, six food densities, and four culture densities. Times elapsed until 50% of the population had reached...... a copepodite stage (DT(½) ) at the different conditions were calculated. The DT(½) values decreased from 296 h at 15°C to 89 h at 25°C and were also affected by salinity (126 h at 15‰ and 167 h at 30‰), whereas the light:dark regime and culture density influenced development only to a minor extent. BP1...

  1. Embryonic cold storage capability from seven strains of Acartia spp. isolated in different geographical areas

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Buttino, Isabella; Cunha, Maria Emilia;

    2016-01-01

    Calanoid copepods from the genus Acartia are well studied because they are promising live feeds in marine larviculture. Several Acartia spp. are adapted to the occurrence of sudden unfavorable environmental conditions and can arrest their embryogenesis by entering quiescence. This trait can be us...

  2. Genetic responses of the marine copepod Acartia tonsa (Dana) to heat shock and epibiont infestation

    DEFF Research Database (Denmark)

    Petkeviciute, Egle; Kania, Per Walter; Skovgaard, Alf

    2015-01-01

    Expression of stress-related genes was investigated in the marine copepod Acartia tonsa in relation to heat shock at two different salinities (10 and 32‰), and it was furthermore investigated whether experimentally induced epibiont infestation led to elevated expression of stress-related genes...

  3. Blind dating - mate finding in planktonic copepods. III. Hydromechanical communication in Acartia tonsa

    DEFF Research Database (Denmark)

    Bagoien, E.; Kiørboe, Thomas

    2005-01-01

    Mate-finding behaviour in the marine copepod Acartia tonsa was examined by video analysis. A. tonsa appears to depend on hydromechanical signals in the location of mates, detected at distances of up to 5 or 7 mm. Series of up to 7 or 8 synchronised hops in closely situated individuals, interpreted...

  4. Calanoid copepods of the International Indian Ocean Expedition

    Digital Repository Service at National Institute of Oceanography (India)

    Stephen, R.; Devi, K.S.; Meenakshikunjamma, P.P.; Gopalakrishnan, T.C.; Saraswathy, M.

    to the NW Indian Ocean, and Metridia was predominant near South Africa. Calanoides occured very scattered, with some large catches off Java and Oman, upwelling areas during the summer monsoon. High densities of all the major groups were encountered...

  5. SWIMMING BEHAVIOR OF DEVELOPMENTAL STAGES OF THE CALANOID COPEPOD TEMORA-LONGICORNIS AT DIFFERENT FOOD CONCENTRATIONS

    NARCIS (Netherlands)

    VANDUREN, LA; VIDELER, JJ

    1995-01-01

    The swimming behaviour of developmental stages of the marine calanoid copepod Temora longicornis was studied using 2-dimensional observations under a microscope and a 3-dimensional filming technique to analyze swimming mode, swimming speed and swimming trajectories under different food concentration

  6. Influence of LAS on marine calanoid copepod population dynamics and potential reproduction

    DEFF Research Database (Denmark)

    Christoffersen, Kirsten; Hansen, Benni Winding; Johansson, Liselotte Sander

    2003-01-01

    The toxicity of linear alkyl benzene sulfonate (LAS) to marine invertebrates is well documented under laboratory conditions using single-species tests. It is less known how LAS affects natural populations of aquatic organisms. We hypothesised that LAS was more toxic to the calanoid copepod Acarti...

  7. Dealing with the presence of the ciliate Euplotes sp. in cultures of the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Dutz, Jörg

    2014-01-01

    Ciliates in live feed cultures can be a pest that lower production yields. This could dramatically affect the management and success of copepod cultures. In this study, we investigated the effect of the ciliate Euplotes sp. on egg production, specific egg production and egg hatching success...... of Acartia tonsa fed with Rhodomonas salina. We found that at a concentration of 2 cells ml-1, Euplotes sp. had no effect on the production and hatching success of eggs but increased/decreased the mortality/quality of non-subitaneous eggs. Euplotes sp. had a good fatty acid profile containing high proportion...

  8. Astaxanthin, canthaxanthin and astaxanthin esters in the copepod Acartia bifilosa (Copepoda, Calanoida during ontogenetic development

    Directory of Open Access Journals (Sweden)

    Maria £otocka

    2001-12-01

    Full Text Available The contents of astaxanthin, canthaxanthin and astaxanthin esters were studied in natural populations of the copepod Acartia bifilosa from the Pomeranian Bay and Gulf of Gdansk in the southern Baltic Sea. Samples dominated by any one of three developmental groups: (1 nauplii, (2 copepodids I-III and (3 copepodids IV-V and adults of Acartia bifilosa were analysed by means of high performance liquid chromatography (HPLC. As ontogenetic development progressed, significant changes occurred in the proportion of particular pigments in the total pigment pool of the various developmental groups. Astaxanthin and canthaxanthin occurred in all the groups, the former being clearly dominant. However, an increasing percentage of astaxanthin esters was recorded in the copepodids I-III, and even more in the copepodids IV-V and adults group. Most probably, astaxanthin is the main pigment active in copepod lipid metabolism. Carotenoid pigments in copepods very likely act as efficient free-electron quenchers and may be involved as antioxidants in rapid lipid metabolism. The exogenously feeding stages (late nauplii and copepodids transform plant carotenoids taken from food and are evidently capable of metabolising astaxanthin by esterification and further degradation. It is emphasised that, according to literature data, astaxanthin esters may have an even higher quenching ability. It is suggested that crustacean carotenoid pigments, with their electron donor-acceptor abilities, may replace oxygen in peroxidation processes connected with lipid metabolism. The consequences of such a physiological role of astaxanthin for present-day estimations of energy balances in zooplankton communities are mentioned.

  9. Food size spectra, ingestion and growth of the copepod Acartia tonsa during development: implications for the determination of copepod production

    DEFF Research Database (Denmark)

    Berggren, U.; Hansen, B.; Kiørboe, Thomas

    1988-01-01

    stage. Since the biomass of particulate matter is approximately constant in equal logarithmic size classes in the sea, food availability may be similar for all developmental stages in the average marine environment. Juvenile specific growth rate was exponential and increased hyperbolically with food......Clearance rates on different sizes of spherically shaped algae were determined in uni-algal experiments for all developmental stages (NII through adult) of the copepodAcartia tonsa, and used to construct food size spectra. Growth and developmental rates were determined at 7 food levels (0 to 1 500...... g C l-1 ofRhodomonas baltica). The lower size limit for particle capture was between 2 and 4 m for all developmental stages. Optimum particle size and upper size limit increased during development from 7 m and 10 to 14 m for NII to NIII to 14 to 70 m and 250 m for adults, respectively. When food...

  10. Biochemical composition of the promising live feed tropical calanoid copepod Pseudodiaptomus annandalei (Sewell 1919) cultured in Taiwanese outdoor aquaculture ponds

    DEFF Research Database (Denmark)

    Rayner, Thomas Allan; Jørgensen, Niels O. G.; Blanda, Elisa;

    2015-01-01

    The use of copepods as live feed has shown good potential, and in Taiwan copepods are harvested specifically as live feed for fin-fish production. The calanoid copepod Pseudodiaptomus annandalei is a species found typically in Taiwanese aquaculture and in the rest of the Indo-Pacific region....... The copepods, as well as seston, were sampled from outdoor large-scale aquaculture ponds in southern Taiwan during a three week period in the summer, and their somatic biomass, fatty acid and amino acid profiles were examined. The resulting fatty acid profiles of the copepods and pond seston were compared.......2%, combined with an estimated protein content of 57% of dry weight for adult females. Both the fatty and amino acid profiles show favourable nutritional values towards fish larvae rearing. Further investigation into P. annandalei's potential biosynthetic capabilities and intake of particles other than pelagic...

  11. Rates of ingestion and their variability between individual calanoid copepods: Direct observations

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhoefer, G.A.; Lewis, K.D. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Bundy, M.H. [Skidaway Inst. of Oceanography, Savannah, GA (United States)]|[Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE); Metz, C. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE)

    1995-12-01

    The goals of this study were to determine rates of ingestion and fecal pellet release, and their variability, for individual planktonic copepods over extended periods of time (>20 min). Ingestions and rejections of individual cells of the diatom Thalassiosira eccentrica by a adult females of the calanoid Paracalanus aculeatus were directly quantified by observing individual copepods continuously at cell concentrations ranging from 0.1 to 1.2 mm{sup 3} l{sup {minus}1}. Average ingestion rates increased with increasing food concentration, but were not significantly different between 0.3 and 1.0 mm{sup 3} l{sup {minus}1} (9.8 and 32.7 {mu}g Cl{sup {minus}1}) of T.eccentrica. Rates of cell rejections were low and similar at 0.1 and 0.3. but were significantly higher at 1.0 mm{sup 3} l{sup {minus}1}. The coefficients of variation for average ingestion rates of individual copepods hardly differed between food concentrations, ranging from 17 to 22%, and were close to those for average fecal pellet release intervals which ranged from 15 to 21%. A comparison between individuals at each food concentration found no significant differences at 1.0; at 0.1 and 0.3 mm{sup 3} l{sup {minus}1}, respectively, ingestion rates of four out of five females did not differ significantly from each other. Average intervals between fecal pellet releases were similar at 0.3 and 1.0 mm{sup 3} l{sup {minus}1}. Fecal pellet release intervals between individuals were significantly different at each food concentration; these significant differences were attributed to rather narrow ranges of pellet release intervals of each individual female. Potential sources/causes of variability in the sizes and rates of copepods in the ocean are evaluated.

  12. Response of Acartia tonsa to Burgers' Vortex: Deconstructing Turbulence-Copepod Interactions

    Science.gov (United States)

    Young, D. L.; Webster, D. R.; Yen, J.

    2014-11-01

    In situ studies suggest that in many oceanic regimes, turbulence affects the vertical position of copepods primarily by changing their behavior, and only secondarily by altering their physical position. We test the hypothesis that fine-scale turbulence alters copepod behavior, presenting as alterations in directed movement and changes in swimming kinematics. To this end, we create two Burgers' vortices, specifying the rotation rate and axial strain rate to correspond to turbulent vortices with size scale equaling the inverse wavenumber of the median viscous dissipation rate (i.e. r = 8.1 η) for typical turbulent conditions in the coastal or near surface region (i.e., mean turbulent dissipation rates of 0.009 and 0.096 cm2/s3) . The vortex flow is quantified via tomo-PIV. Behavioral assays of Acartia tonsa are conducted, generating 3D trajectories for analysis of swimming kinematics and response to hydrodynamic cues. A. tonsa did not significantly respond to the vortex corresponding to dissipation rate of 0.009 cm2/s3, but drastically altered their swimming behavior in the presence of the 0.096 cm2/s3 vortex, including increased relative swim speed, angle of alignment with the vortex axis, net-to-gross displacement ratio, and escape acceleration, along with decreased turn frequency (relative to stagnant control conditions). Further, A. tonsa escape location is preferentially in the core of the stronger vortex, indicating that the hydrodynamic cue triggering the distinctive escape behavior is vorticity.

  13. Feeding behavior of large calanoid copepods Neocalanus cristatus and N. plumchrus from the subarctic Pacific Ocean

    Science.gov (United States)

    Frost, B. W.; Landry, M. R.; Hassett, R. P.

    1983-01-01

    Oceanic waters of the subarctic Pacific exhibit a special ecological feature, a virtually seasonally invariant standing stock of phytoplankton (measured as chlorophyll a), that seems to reflect a balance, at least during spring and summer, between phytoplankton growth and zooplankton grazing. The grazers presumed to be responsible for the balance are the calanoid copepods Neocalanus cristatus and N. plumchrus. Shipboard grazing experiments, utilizing both natural suspended particulate material and cultured phytoplankton as food for the copepods, showed that both species have at least three attributes of feeding behavior required to maintain steady standing stock of phytoplankton. That is, the Neocalanus species can feed at the low concentrations of phytoplankton that prevail in the open subarctic Pacific, they feed at similar rates on a broad range of particlessizes including the predominant particles, and they respond to small increases in phytoplankton concentration by proportionately larger increases in their feeding rate. Although both species of Neocalanus attain larger body sizes than co-occurring Calanus pacificus and Pseudocalanus sp., they have morphological specializations that seem to account for their unexpected ability to feed on very dilute suspensions of small phytoplankton cells. It appears that the perpetually low phytoplankton concentrations in the open subarctic Pacific do not permit maximum feeding effort by the species of Neocalanus.

  14. Annual egg production rates of calanoid copepod species on the continental shelf of the Eastern Tropical Pacific off Mexico

    Science.gov (United States)

    Kozak, Eva R.; Franco-Gordo, Carmen; Palomares-García, Ricardo; Gómez-Gutiérrez, Jaime; Suárez-Morales, Eduardo

    2017-01-01

    We provide the first estimations of calanoid copepod egg production rates (EPR) in the Eastern Tropical Pacific over an annual cycle (January-December 2011). Gravid females were collected twice monthly and incubated for 12 h without food to estimate EPR, weight-specific fecundity (Gf), spawning success (SS, percentage of females to spawn out of the total species incubated per month and season) and egg hatching success (EHS). This study reports the average EPR of 10 species and the monthly EPR and Gf of four planktonic calanoid copepods (Centropages furcatus, Temora discaudata, Pontellina sobrina, and Nannocalanus minor) that spawned with enough frequency to infer their seasonal reproductive patterns. These species showed distinct seasonal reproductive strategies. Most copepod species spawned sporadically with large EPR variability, while three copepod species reproduced throughout the year (C. furcatus, T. discaudata and P. sobrina) and N. minor spawned only during the mixed period (Feb-May). The four species had relatively similar average EPR (C. furcatus 16, T. discaudata 18, P. sobrina 13, and N. minor 12 eggs fem-1 day-1). These are the first EPR estimations of P. sobrina and its previously known reproductive period is expanded. A Canonical Correspondence Analysis (CCA) was used to analyze EPR and species abundance of all calanoid copepods (40 spp.) collected throughout the time series in relation to temperature, salinity, mixed layer depth (MLD), dissolved oxygen, and chlorophyll a (Chl-a) concentrations to identify the variables that best explained the copepod abundance variability. Temperature, Chl-a, and salinity had the strongest effect on the biological variables, linked to seasonal and episodic upwelling-downwelling processes in the surveyed area. As a result of moderate upwelling events and seasonal variation of environmental conditions, it appears relatively few species are capable of maintaining continuous reproduction under the relatively higher

  15. Outdoor rearing facilities of free spawning calanoid copepods for turbot larva can host a bank of resting eggs in the sediment

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Blanda, Elisa; Drillet, Guillaume;

    2016-01-01

    match the larval needs. When turbot larvae reach metamorphosis and are transferred indoor for weaning, the outdoor tank sediments may reveal vast amounts of copepod eggs undergoing dormancy. Here, we report a copepod species succession firstly among Centropages hamatus and then Acartia spp. both...

  16. Diet influence on egg production of the copepod Acartia tonsa (Dana, 1896

    Directory of Open Access Journals (Sweden)

    Priscila F. Teixeira

    2010-06-01

    Full Text Available Egg production in the copepod Acartia tonsa was evaluated using different densities of the microalgae Thalassiosira weissflogii, Chaetoceros muelleri and Isochrysis galbana. Male and female were kept under controlled conditions (salinity 30, 20°C, photoperiod 12L:12D, acclimated to the experimental conditions and left over a period of 24 h to allow copulation. Algal densities tested were equivalent in biovolume and corresponded to 0, 2.5, 5, 10, 20, 40 and 60.10³ cells.mL-1 of T weissflogii. Ten acclimated female were separated, transferred to glass bottles and exposed for further 24 h to the corresponding experimental medium. After this period, the eggs were fixed and counted. Copepod egg production reached a threshold value when T weissflogii, C. muelleri and I. galbana were supplied at 10.10³, 140.10³ and 640.10³ cells.mL-1, respectively. Mean egg production corresponded to 28.0 ± 0.5, 20.1 ± 1.0 and 22.0 ± 3.5 eggs.female-1 .day-1, respectively. Copepods fed T weissflogii showed the highest mean egg production while those fed I. galbana reached a maximum egg production when the algae were supplied at a density two- to fourfold higher, considering the biovolume of T weissflogii and C. muelleri. These differences are explained considering the different sizes of the microalgae used to feed the copepods.A produção de ovos do copépode Acartia tonsa foi avaliada utilizando diferentes densidades das microalgas Thalassiosira weissflogii, Chaetoceros muelleri e Isochrysis galbana. Machos e fêmeas foram colocados sob condições controladas (salinidade 30, 20°C, fotoperíodo 12L:12D, aclimatados às condições experimentais e mantidos juntos por 24 h para permitir a copula. As densidades de algas foram equivalentes em biovolume e corresponderam a 0, 2,5, 5, 10, 20, 40 e 60,10³ células.mL-1 de T. weissflogii. Dez fêmeas aclimatadas foram separadas, transferidas para frascos de vidro e expostas por mais 24 h ao meio experimental

  17. Linking foraging strategies of marine calanoid copepods to patterns of nitrogen stable isotope signatures in a mesocosm study

    DEFF Research Database (Denmark)

    Sommer, Frank; Saage, A.; Santer, B.

    2005-01-01

    foraging mode and, further, with its nitrogen stable isotope signature (delta(15)N). This is because a more carnivorous diet may be expected to result in a higher delta(15)N. We tested this hypothesis in a mesocosm study using a density gradient (0 to 80 ind. 1(-1)) of calanoid copepods. We expected......, whereas nanoflagellates increased with increasing copepod density. As expected, Centropages hamatus, a cruising species, showed the strongest isotopic increase and also highest population growth at low copepod density, suggesting that it was the most efficient species in capturing ciliates. Temora...... longicornis, a stationary suspension-feeder, showed a uniform isotopic increase in all mesocosms, which we believe resulted from nutritional stress arising from poor feeding on both ciliates (too fast for ingestion by T. longicornis) and nanoflagellates (too small). However, Pseudocalanus elongatus, a species...

  18. Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia

    Science.gov (United States)

    Huang, Ying; Zhu, Liyan; Qiu, Xuchun; Zhang, Tianwen

    2010-03-01

    A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L-1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control ( Paborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased r m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.

  19. Effects of the oxylipin-producing diatom Skeletonema marinoi on gene expression levels of the calanoid copepod Calanus sinicus.

    Science.gov (United States)

    Lauritano, Chiara; Carotenuto, Ylenia; Vitiello, Valentina; Buttino, Isabella; Romano, Giovanna; Hwang, Jiang-Shiou; Ianora, Adrianna

    2015-12-01

    Diatoms are eukaryotic unicellular plants that constitute one of the major components of marine phytoplankton, comprising up to 40% of annual productivity at sea and representing 25% of global carbon-fixation. Diatoms have traditionally been considered a preferential food for zooplankton grazers such as copepods, but, in the last two decades, this beneficial role has been challenged after the discovery that many species of diatoms produce toxic metabolites, collectively termed oxylipins, that induce reproductive failure in zooplankton grazers. Diatoms are the dominant natural diet of Calanus sinicus, a cold-temperate calanoid copepod that supports secondary production of important fisheries in the shelf ecosystems of the Northwest Pacific Ocean, Yellow Sea, Sea of Japan and South China Sea. In this study, the effect of the oxylipin-producing diatom Skeletonema marinoi on C. sinicus has been evaluated by analyzing expression level changes of genes involved in defense and detoxification systems. Results show that C. sinicus is more resistant to a diet of this diatom species in terms of gene expression patterns, compared to the congeneric species Calanus helgolandicus which is an important constituent of the temperate waters of the Atlantic Ocean and northern Mediterranean Sea. These findings contribute to the better understanding of genetic and/or phenotypic flexibility of copepod species and their capabilities to cope with stress by identifying molecular markers (such as stress and detoxification genes) as biosensors for environmental perturbations (e.g. toxins and contaminants) affecting marine copepods.

  20. The toxicity of the three antifouling biocides DCOIT, TPBP and medetomidine to the marine pelagic copepod Acartia tonsa.

    Science.gov (United States)

    Wendt, Ida; Backhaus, Thomas; Blanck, Hans; Arrhenius, Åsa

    2016-07-01

    Copepods, the largest group of pelagic grazers, are at risk from exposure to antifouling biocides. This study investigated the toxicity of the antifouling biocides 4,5-dichloro-2-octyl-1,2-thiazol-3(2H)-one (DCOIT), triphenylborane pyridine (TPBP) and 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (medetomidine) to the copepod Acartia tonsa, using mortality and egg production as endpoints. The toxicity ranking for mortality was as follows: DCOIT (LC50 57 nmol l(-1)) = TPBP (LC50 56 nmol l(-1)) > medetomidine (LC50 241 nmol l(-1)). Egg production was more sensitive than mortality to TPBP (EC50 3.2 nmol l(-1)), while DCOIT and medetomidine inhibited egg production at roughly the same concentrations (72 and 186 nmol l(-1) respectively). Furthermore, TPBP seems to affect egg hatching directly which was not the case for DCOIT and medetomidine. DCOIT and medetomidine might pose an environmental risk as they have been reported to occur in different exposure scenarios or analytical surveys at concentrations only 2-3 times lower than the respective EC10. Reported environmental concentrations of TPBP are few but clearly lower than the EC10 values reported here, suggesting current risk of TPBP to copepods to be moderate.

  1. Feeding strategies of tropical and subtropical calanoid copepods throughout the eastern Atlantic Ocean - Latitudinal and bathymetric aspects

    Science.gov (United States)

    Bode, Maya; Hagen, Wilhelm; Schukat, Anna; Teuber, Lena; Fonseca-Batista, Debany; Dehairs, Frank; Auel, Holger

    2015-11-01

    The majority of global ocean production and total export production is attributed to oligotrophic oceanic regions due to their vast regional expanse. However, energy transfers, food-web structures and trophic relationships in these areas remain largely unknown. Regional and vertical inter- and intra-specific differences in trophic interactions and dietary preferences of calanoid copepods were investigated in four different regions in the open eastern Atlantic Ocean (38°N to 21°S) in October/November 2012 using a combination of fatty acid (FA) and stable isotope (SI) analyses. Mean carnivory indices (CI) based on FA trophic markers generally agreed with trophic positions (TP) derived from δ15N analysis. Most copepods were classified as omnivorous (CI ∼0.5, TP 1.8 to ∼2.5) or carnivorous (CI ⩾ 0.7, TP ⩾ 2.9). Herbivorous copepods showed typical CIs of ⩽0.3. Geographical differences in δ15N values of epi- (200-0 m) to mesopelagic (1000-200 m) copepods reflected corresponding spatial differences in baseline δ15N of particulate organic matter from the upper 100 m. In contrast, species restricted to lower meso- and bathypelagic (2000-1000 m) layers did not show this regional trend. FA compositions were species-specific without distinct intra-specific vertical or spatial variations. Differences were only observed in the southernmost region influenced by the highly productive Benguela Current. Apparently, food availability and dietary composition were widely homogeneous throughout the mesotrophic oceanic regions of the tropical and subtropical Atlantic. Four major species clusters were identified by principal component analysis based on FA compositions. Vertically migrating species clustered with epi- to mesopelagic, non-migrating species, of which only Neocalanus gracilis was moderately enriched in lipids with 16% of dry mass (DM) and stored wax esters (WE) with 37% of total lipid (TL). All other species of this cluster had low lipid contents (deep

  2. Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods

    DEFF Research Database (Denmark)

    Tammilehto, Anna; Nielsen, Torkel Gissel; Krock, B.;

    2015-01-01

    The toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane)to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoicacid production and chain formation in P. seriata. The toxicity of P. seriata increased in ...

  3. Guide to the meso-scale production of the copepod Acartia tonsa

    OpenAIRE

    Marchus, Nancy H.; Wilcox, Jeffrey A.

    2007-01-01

    This manual is intended as a guide for the daily production of a few million A. tonsa nauplii for feeding to marine vertebrates and invertebrates. This scale of production is greater than most research would require, but smaller than commercial production, hence the term meso-scale production. This manual will briefly describe the biology of Acartia tonsa Dana that is relevant to culture, the culture methodology for meso-scale production of their eggs and nauplii, the system co...

  4. Effects of Temperature, Salinity, pH, and Light on Filtering and Grazing Rates of a Calanoid Copepod (Schmackeria dubia

    Directory of Open Access Journals (Sweden)

    Changling Li

    2008-01-01

    Full Text Available Calanoid copepods are key components of the marine food web and the food sources of many larval fishes and planktivores, and grazers of phytoplankton. Understanding the ranges of major environmental variables suitable for their growth is essential to maintain the balance between trophic links and resources protection. In this study, the effects of temperature, salinity, pH, and light intensity on the filtering and grazing rates of a herbivorous copepod (Schmackeria dubia were conducted in several control experiments. Our results indicated that experimental animals grazed normally at water temperatures between 15 and 35°C. The filtering and grazing rates increased by onefold at water temperatures from 15 to 25°C, with a peak at around 30°C. S. dubia fed normally at salinity ranging from 20 to 30 ppt, with significantly low filtering and grazing rates at salinity below 15 ppt and above 35 ppt. The filtering and grazing rates increased as pH increased, peaked at approximately 8.5, and then decreased substantially. Light intensity also displayed an important impact on the filtering and grazing rates. Filtering and grazing rates were high when light intensity was greater than 20 and less than 200 µmol m-2 s-1. S. dubia nearly stopped feeding at low light intensity (less than 20 µmol m-2 s-1.

  5. Vertical distribution, grazing and egg production of calanoid copepods during winter-spring in Gullmarsfjorden

    DEFF Research Database (Denmark)

    Titelman, J.; Tiselius, P.

    1998-01-01

    The vertical distribution of copepods in relation to their potential food was examined in Gullmarsfjorden, Sweden (58 degrees 15.6' N, 11 degrees 27.2' E). Plankton distributions were determined from bottle samples at 5 m intervals on four occasions; 30 January, 28 February, 7 March and 10 April...... were superfluous throughout the water column. Copepods and ciliates were never correlated. Ingestion as determined from gut fluorescence and egg production analyses suggested a higher degree of herbivory during the spring bloom than before and after. There was potential for copepod predation control...

  6. Do inactivated Microbial Preparations Improve Life History Traits of the Copepod Acartia tonsa?

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Rabarimanantsoa, Tahina; Frouel, Stéphane;

    2011-01-01

    of the PSI revealed that it is a nutritionally poor food lacking essential fatty acids, and hence it cannot be used alone to raise copepods but instead as a food additive. This is the first demonstration that the effectiveness of copepod culturing can be improved using microbial preparations as a food...... show that the addition of PSI to the algal food increased the individual size of the adult females and their egg production. The PSI, together with Rhodomonas salina, also increased the HS of the eggs produced by PSI-treated females. These effects were observed despite that the biochemical analysis...

  7. First feeding of Eugerres brasilianus (Carapeva larvae with Acartia tonsa (Copepod nauplii increases survival and resistance to acute stress

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo Costa

    2016-01-01

    Full Text Available The rotifer Brachionus sp. is commonly used for larval feeding in marine fish hatcheries. The aim of this study was to evaluate whether the inclusion of Acartia tonsa nauplii in the initial diet of carapeva larvae improves their survival, growth and resistance to stress when compared to the regimen containing only rotifers. Adult copepods were collected in the wild and cultured with the microalgae Chaetoceros muelleri, Isochrysis galbana and Nannochloropsis oculata to obtain nauplii. Carapeva larvae were grown for 15 days using four treatments and three replicates: 1 Brachionus plicatilis rotifers (10 to 15/mL; 2 A. tonsa nauplii (0.25 to 0.5/mL; 3 Brachionus plicatilis rotifers (5 to 7.5/mL + A. tonsa nauplii (0.12 to 0.25/mL, and 4 no supply of live feed. After 15 days, the carapeva larvae were subjected to stress by exposure to air for 10 seconds and then returned to the source tank to evaluate survival after 24 h. Survival and stress resistance were higher in carapeva larvae fed B. plicatilis + A. tonsa nauplii (P<0.05, 20.9 ± 11.2% and 88.9%, respectively. These results confirm the positive effect of the inclusion of copepod nauplii in the diet of fish larvae. However, more research is needed to validate these results.

  8. Toxic effects of polyethylene terephthalate microparticles and Di(2-ethylhexyl)phthalate on the calanoid copepod, Parvocalanus crassirostris.

    Science.gov (United States)

    Heindler, Franz M; Alajmi, Fahad; Huerlimann, Roger; Zeng, Chaoshu; Newman, Stephen J; Vamvounis, George; van Herwerden, Lynne

    2017-03-30

    Large amounts of plastic end up in the oceans every year where they fragment into microplastics over time. During this process, microplastics and their associated plasticizers become available for ingestion by different organisms. This study assessed the effects of microplastics (Polyethylene terephthalate; PET) and one plasticizer (Di(2-ethylhexyl)phthalate; DEHP) on mortality, productivity, population sizes and gene expression of the calanoid copepod Parvocalanus crassirostris. Copepods were exposed to DEHP for 48h to assess toxicity. Adults were very healthy following chemical exposure (up to 5120µg L(-1)), whereas nauplii were severely affected at very low concentrations (48h LC50value of 1.04 ng L(-1)). Adults exposed to sub-lethal concentrations of DEHP (0.1-0.3µg L(-1)) or microplastics (10,000-80,000 particles mL(-1)) exhibited substantial reductions in egg production. Populations were exposed to either microplastics or DEHP for 6 days with 18 days of recovery or for 24 days. Populations exposed to microplastics for 24 days significantly depleted in population size (60±4.1%, precovery) experienced less severe depletions (75±6.0% of control, precovery and both treatments (6 and 24 days) yielded the same average population size at the termination of the experiment (59±4.9% and 59±3.4% compared to control; precovery. Hsp70-like expression showed to be unresponsive to either DEHP or microplastic exposure. Clearly, microplastics and plasticizers pose a serious threat to zooplankton and potentially to higher trophic levels.

  9. Effect of temperature and viscosity on swimming velocity of the copepod Acartia tonsa, brine shrimp Artemia salina and rotifer Brachionus plicatilis

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Madsen, C.V.; Riisgard, H.U.

    2008-01-01

    of swimming velocity for a 10 degrees C temperature reduction) that is found to be largest for the brine shrimp Artemia salina nauplius (37 %) and the rotifer Brachionus plicatilis (26%), but negligible for the copepod Acartia tonsa (4%). We suggest that experimental data on change in swimming velocity (V......Beating cilia are important organelles for swimming in many zooplanktonic aquatic organisms, including many invertebrate larvae, rotifers and ciliates, but other planktonic organisms, such as copepods and brine shrimps, use muscle-powered swimming appendages. In recent studies we found......) due to change in kinematic viscosity (v) be correlated in terms of a power law, V proportional to v(-m). The present data on swimming velocity of copepods, brine shrimps and rotifers show values of exponent m approximate to 1.5 to 3, with a trend of decreasing values for increasing size of species...

  10. Prymnesium parvum exotoxins affect the grazing and viability of the calanoid copepod Eurytemora affinis

    DEFF Research Database (Denmark)

    Sopanen, S.; Koski, Marja; Uronen, P.;

    2008-01-01

    on grazers, and these effects are stronger under nutrient-depleted conditions; however, the presence of good-quality food lowers harmful effects for copepods. The negative effects caused either by direct intoxication or by food limitation following from strong allelopathic effects of P. parvum on other...... were incubated (1) in increasing concentrations of cell-free filtrates of P. parvum in the presence of good food (R, salina), (2) in 1:1 cell mixtures at 2 cell concentrations of P. parvum and R. salina and (3) in R. salina cell suspension, which was used as a control for good-quality food. P. parvum...... components of nano- and microplankton suggest that P. parvum blooms have a realistic potential to be deleterious for copepod secondary production, irrespective of the presence of alternative food sources....

  11. Impact of the diatom-derived polyunsaturated aldehyde 2-trans,4-trans decadienal on the feeding, survivorship and reproductive success of the calanoid copepod Temora stylifera.

    Science.gov (United States)

    Kâ, Samba; Carotenuto, Ylenia; Romano, Giovanna; Hwang, Jiang-Shiou; Buttino, Isabella; Ianora, Adrianna

    2014-02-01

    Many diatoms, a major class of unicellular algae contributing to over 45% of oceanic primary production, are known to induce deleterious effects on reproductive processes in crustacean copepods. This is mainly due to the production of teratogenic oxylipins, including polyunsaturated aldehydes (PUAs). Here we tested the direct effect of the PUA 2E,4E-decadienal (DD) on feeding activity, survivorship and reproductive success of the calanoid copepod Temora stylifera. DD-inoculated cultures induced high mortality at concentrations above 3 μg mL(-1) compared to controls in both males and females, with males having a higher mortality. Low DD concentrations triggered an increase in female filtration and ingestion rates. Egg production rates and hatching times were also higher in the presence of DD, whereas egg hatching success decreased with increasing DD concentration. Our study shows, for the first time, that the presence of diatom PUAs may increase feeding rates in copepods.

  12. Rapid adaptation to oil exposure in the cosmopolitan copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Krause, K. E.; Dinh, Khuong Van; Nielsen, Torkel Gissel

    Oil spills are potential environmental hazards to marine ecosystems worldwide. Oil spills may persist in seawater longer than one generation of many zooplankton species. However, whether populations of short-lived and fast growing marine organisms adapt to oil exposure through natural selection...... that populations of short-lived and fast-growing copepods have the potential of showing surprisingly strong resilience to the type of oil contamination they might face in their natural coastal habitats...

  13. Inclusion of copepod Acartia tonsa nauplii in the feeding of Centropomus undecimalis larvae increases stress resistance

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo-Costa

    2015-09-01

    Full Text Available This research represents the first result of studies of the common snook Centropomus undecimalis larvae from broodstock matured in captivity in Brazil. The aim of this study was to evaluate if the inclusion of Acartia tonsa nauplii improves stress resistance of common snook larvae. The larvae were fed with: rotifers Brachionus plicatilis (10 to 15 mL-1; A. tonsa nauplii (0.25 to 0.5 mL-1 and rotifers (5 to 7.5 mL-1, and A. tonsa nauplii (0.12 to 0.25 mL-1. The average percentage of survival of the treatments was 11.9%. At 20 days of age, larvae were subjected to thermal stress. Subsequently, the stress resistance was evaluated. Common snook larvae fed B. plicatilis+A. tonsa reached a higher weight and length (7.5 ± 0.00 mg and 9.1 ± 0.23 mm, respectively and resisted more heat stress (87.4% than larvae fed other foods, indicating that the feed mixture is satisfactory as a starter diet for larvae of common snook. However, more research is needed to confirm these results.

  14. Observations on feeding behaviour and survival rates in the estuarine calanoid copepods Acartia spinicauda and Heliodiaptomus cinctus (Crustacea: Copepoda: Calanoida)

    Digital Repository Service at National Institute of Oceanography (India)

    Srivastava, Y.; Fernandes, Brenda; Goswami, S.C.; Goswami, U.; Achuthankutty, C.T.

    of Tetraselmis gracilis (Chlorophyta) and Skeletonema costatum (Bacillariophyta), whereas, adults of H. cinctus were fed on five different combinations of phytoplankton feed. Total hourly differences in pigment concentrations indicate that A. spinicauda preferred...

  15. Effect of alternative mediums on production and proximate composition of the microalgae Chaetoceros muelleri as food in culture of the copepod Acartia sp. Efecto de medios alternativos sobre la producción y composición proximal de la microalga Chaetoceros muelleri como alimento en cultivo del copépodo Acartia sp.

    OpenAIRE

    Martínez-Córdova, Luis R.; Alfredo Campaña-Torres; Marcel Martinez-Porchas; José A López-Elías; Celia O García-Sifuentes

    2012-01-01

    Microalgae Chaetoceros muelleri was cultured in three different mediums consisting on an agricultural fertilizer (Agr-F), aquacultural fertilizer (Aq-F) and a conventional medium (F/2, control). These microalgae were later used as natural food to culture the copepod Acartia sp. The productive response and chemical proximate composition of microalgae and copepods were monitored. Growth rate and final cell concentration were higher in microalgae cultured in Agr-F compared to the control. In add...

  16. Effects of Calanoid Copepod Schmackeria poplesia as a Live Food on the Growth, Survival and Fatty Acid Composition of Larvae and Juveniles of Japanese Flounder, Paralichthys olivaceus

    Institute of Scientific and Technical Information of China (English)

    LIU Guangxing; XU Donghui

    2009-01-01

    Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods (P<0.01). Three live organisms were used for raising larvae and juveniles ofParalichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods (S. poplesia) had significantly higher growth rate than thosc fed with the other two organisms (P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others (P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia (P<0.05). The contents of three types of HUFAs (DHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

  17. Determining the Advantages, Costs, and Trade-Offs of a Novel Sodium Channel Mutation in the Copepod Acartia hudsonica to Paralytic Shellfish Toxins (PST.

    Directory of Open Access Journals (Sweden)

    Michael Finiguerra

    Full Text Available The marine copepod Acartia hudsonica was shown to be adapted to dinoflagellate prey, Alexandrium fundyense, which produce paralytic shellfish toxins (PST. Adaptation to PSTs in other organisms is caused by a mutation in the sodium channel. Recently, a mutation in the sodium channel in A. hudsonica was found. In this study, we rigorously tested for advantages, costs, and trade-offs associated with the mutant isoform of A. hudsonica under toxic and non-toxic conditions. We combined fitness with wild-type: mutant isoform ratio measurements on the same individual copepod to test our hypotheses. All A. hudsonica copepods express both the wild-type and mutant sodium channel isoforms, but in different proportions; some individuals express predominantly mutant (PMI or wild-type isoforms (PWI, while most individuals express relatively equal amounts of each (EI. There was no consistent pattern of improved performance as a function of toxin dose for egg production rate (EPR, ingestion rate (I, and gross growth efficiency (GGE for individuals in the PMI group relative to individuals in the PWI expression group. Neither was there any evidence to indicate a fitness benefit to the mutant isoform at intermediate toxin doses. No clear advantage under toxic conditions was associated with the mutation. Using a mixed-diet approach, there was also no observed relationship between individual wild-type: mutant isoform ratios and among expression groups, on both toxic and non-toxic diets, for eggs produced over three days. Lastly, expression of the mutant isoform did not mitigate the negative effects of the toxin. That is, the reductions in EPR from a toxic to non-toxic diet for copepods were independent of expression groups. Overall, the results did not support our hypotheses; the mutant sodium channel isoform does not appear to be related to adaptation to PST in A. hudsonica. Other potential mechanisms responsible for the adaptation are discussed.

  18. Molecular and microscopic evidence of viruses in marine copepods.

    Science.gov (United States)

    Dunlap, Darren S; Ng, Terry Fei Fan; Rosario, Karyna; Barbosa, Jorge G; Greco, Anthony M; Breitbart, Mya; Hewson, Ian

    2013-01-22

    As dominant members of marine mesozooplankton communities, copepods play critical roles in oceanic food webs and biogeochemical cycling. Despite the ecological significance of copepods, little is known regarding the causes of copepod mortality, and up to 35% of total copepod mortality cannot be accounted for by predation alone. Viruses have been established as ecologically important infectious agents in the oceans; however, viral infection has not been investigated in mesozooplankton communities. Here we used molecular and microscopic techniques to document viral infection in natural populations of the calanoid copepods Acartia tonsa (Dana) and Labidocera aestiva (Wheeler) in Tampa Bay, FL. Viral metagenomics revealed previously undocumented viruses in each species, named Acartia tonsa copepod circo-like virus (AtCopCV) and Labidocera aestiva copepod circo-like virus (LaCopCV). LaCopCV was found to be extremely prevalent and abundant in L. aestiva populations, with up to 100% prevalence in some samples and average viral loads of 1.13 × 10(5) copies per individual. LaCopCV transcription was also detected in the majority of L. aestiva individuals, indicating viral activity. AtCopCV was sporadically detected in A. tonsa populations year-round, suggesting temporal variability in viral infection dynamics. Finally, virus-like particles of unknown identity were observed in the connective tissues of A. tonsa and L. aestiva by transmission electron microscopy, demonstrating that viruses were actively proliferating in copepod connective tissue as opposed to infecting gut contents, parasites, or symbionts. Taken together, these results provide strong independent lines of evidence for active viral infection in dominant copepod species, indicating that viruses may significantly influence mesozooplankton ecology.

  19. Ocean acidification challenges copepod phenotypic plasticity

    Science.gov (United States)

    Vehmaa, Anu; Almén, Anna-Karin; Brutemark, Andreas; Paul, Allanah; Riebesell, Ulf; Furuhagen, Sara; Engström-Öst, Jonna

    2016-11-01

    Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ˜ 365-1231 µatm) and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm) or quality (C : N) weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

  20. Do Acartia tonsa (Dana) eggs regulate their volume and osmolality as salinity changes?

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume; Pedersen, Morten Foldager;

    2012-01-01

    Subitaneous eggs from an euryhaline calanoid copepod Acartia tonsa were challenged by changes in salinity within the range from full strength salinity, down to zero and up to >70 psu. Egg volume changed immediately, increasing from 2.8 × 105 μm3 at full strength salinity (35 psu) to 3.8 × 105 μm3...... at 0 psu and back to its initial volume when gradually being returned to full strength salinity. Egg osmolality followed the molality of the surrounding water when challenged within a salinity range from 2 to 50 psu. Egg respiration was not affected when eggs kept at 35 psu was exposed to low salinity...... (2 psu). These results suggest that eggs are unable to regulate their volume or osmolality when challenged with changes in salinity. Gradual changes in salinity from 35 to 2 psu and back did not harm the eggs (embryos), since the hatching success remained unaffected by such changes in salinity...

  1. Influence of two different green algal diets on specific dynamic action and incorporation of carbon into biochemical fractions in the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Thor, P.; Cervetto, G.; Besiktepe, S.;

    2002-01-01

    Previous studies have shown that the two green algae Tetraselmis sp. (Prasinophyceae) and Dunaliella tertiolecta (Chlorophyceae) induce high and low egg production rates in Acartia tonsa. The primary goal of the present study was to investigate if this is attributable to differences in the specific...

  2. Effect of alternative mediums on production and proximate composition of the microalgae Chaetoceros muelleri as food in culture of the copepod Acartia sp. Efecto de medios alternativos sobre la producción y composición proximal de la microalga Chaetoceros muelleri como alimento en cultivo del copépodo Acartia sp.

    Directory of Open Access Journals (Sweden)

    Luis R Martínez-Córdova

    2012-03-01

    Full Text Available Microalgae Chaetoceros muelleri was cultured in three different mediums consisting on an agricultural fertilizer (Agr-F, aquacultural fertilizer (Aq-F and a conventional medium (F/2, control. These microalgae were later used as natural food to culture the copepod Acartia sp. The productive response and chemical proximate composition of microalgae and copepods were monitored. Growth rate and final cell concentration were higher in microalgae cultured in Agr-F compared to the control. In addition, the final biomass and cellular concentration were also the highest in Agr-F. Microalgae from Agr-F and Aq-F had higher carbohydrate and lower protein contents than those in the control. No differences in lipid and ash contents were observed. Regarding copepod production, higher densities and fecundity indexes were observed for those fed with microalgae previously cultured in Agr-F and Aq-F, compared to the control. The adult-nauplii ratio was also higher in copepods fed on microalgae from Agr-F compared to Aq-F and control. Copepods fed on Agr-F and Aq-F microalgae, had higher protein content compared to those fed on control microalgae; carbohydrates were higher in copepods fed on Agr-F as compared to Aq-F microalgae. No differences in lipid and ash contents were registered. Agr-F and Aq-F were adequate alternative mediums to produce C. muelleri, which produced higher quality microalgae that increased the copepod production.La microalga Chaetoceros muelleri fue cultivada en tres medios diferentes basados en un fertilizante agrícola (Agr-F, un fertilizante acuícola (Aq-F y un medio convencional (F/2, control. Éstas microalgas fueron posteriormente utilizadas como alimento natural para cultivar el copépodo Acartia sp. La respuesta productiva y la composición proximal de las microalgas y copépodos fueron monitoreadas. La tasa de crecimiento y concentración final de células fueron mayores en la microalga cultivada en Agr-F, comparada con el control

  3. Copepod Foraging on the Basis of Food Nutritional Quality: Can Copepods Really Choose?

    Science.gov (United States)

    Isari, Stamatina; Antό, Meritxell; Saiz, Enric

    2013-01-01

    Copepods have been considered capable of selective feeding based on several factors (i.e., prey size, toxicity, and motility). However, their selective feeding behaviour as a function of food quality remains poorly understood, despite the potential impact of such a process on copepod fitness and trophodynamics. In this study, we aimed to evaluate the ability of copepods to feed selectively according to the nutritional value of the prey. We investigated the feeding performance of the calanoid copepod Acartia grani under nutritionally distinct diets of the dinoflagellate Heterocapsa sp. (nutrient-replete, N-depleted and P-depleted) using unialgal suspensions and mixtures of prey (nutrient-replete vs. nutrient-depleted). Despite the distinct cell elemental composition among algal treatments (e.g., C:N:P molar ratios) and the clear dietary impact on egg production rates (generally higher number of eggs under a nutrient-replete diet), no impact on copepod feeding rates was observed. All unialgal suspensions were cleared at similar rates, and this pattern was independent of food concentration. When the prey were offered as mixtures, we did not detect selective behaviour in either the N-limitation (nutrient-replete vs. N-depleted Heterocapsa cells) or P-limitation (nutrient-replete vs. P-depleted Heterocapsa cells) experiments. The lack of selectivity observed in the current study contrasts with previous observations, in which stronger nutritional differences were tested. Under normal natural circumstances, nutritional differences in natural prey assemblages might not be sufficiently strong to trigger a selective response in copepods based on that factor alone. In addition, our results suggest that nutritional quality might depend not only on the growing conditions but also on the inherent taxonomical properties of the prey. PMID:24386411

  4. Can we use laboratory reared copepods for experiments - a comparison of feeding behavior and reproduction between a field and a laboratory population of Acartia tonsa

    DEFF Research Database (Denmark)

    Tiselius, P.; Hansen, B.; Jonsson, P.;

    1995-01-01

    Motility patterns and egg production were investigated in two populations of Acartia tonsa, field animals from the Oresund and laboratory animals from a 12-year-old (approximate to 120 generations) culture. When observed in aquaria with a layer of Thalassiosira weissflogii in the middle, laboratory...... animals displayed weak aggregation behaviour, while field animals did not aggregate at all. Both populations made longer and more frequent feeding bouts inside the patch. Egg production measurements were in accordance with the behaviour of the laboratory population if no diel feeding rhythm was assumed...

  5. Response of marine copepods to a changing tropical environment: winners, losers and implications

    Directory of Open Access Journals (Sweden)

    Li Lee Chew

    2016-05-01

    Full Text Available Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985–86 and 2014–15 interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI design. Copepods were identified to species, and results were interpreted by univariate (ANOVA and multivariate (PERMANOVA, PCO analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica. Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons were unaffected

  6. Temperature effects on copepod egg hatching: does acclimatization matter?

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume; Kozmér, A.;

    2010-01-01

    This report investigates female sizes, egg sizes and egg hatching rates in relation to temperature for the near-shore calanoid copepod Acartia tonsa cultured at 6, 9, 14 and 24°C for several generations to achieve acclimatization. Inverse size relationships of eggs and females were revealed...... with increasing temperature. Eggs produced at 6°C were 85 ± 4 µm in diameter, but decreased to 80 ± 3 µm at 24°C. Female cephalothorax length was 840 ± 52 and 692 ± 39 µm at 9 and 24°C, respectively. Parallel hatching experiments were performed between non-acclimatized and acclimatized cultures across a range...... of temperatures reflecting natural conditions in Danish waters. A greater fraction of eggs enter quiescence as temperature declines. Eggs were able to hatch at temperatures as low as 1.5°C. Final egg hatching success increased with temperature. Acclimatization of the copepods resulted in a lower maximum hatching...

  7. Environmental cues and constraints affecting the seasonality of dominant calanoid copepods in brackish, coastal waters: a case study of Acartia, Temora and Eurytemora species in the south-west Baltic

    DEFF Research Database (Denmark)

    Diekmann, A. Berenike S.; Clemmesen, Catriona; St. John, Michael A.;

    2012-01-01

    Information on physiological rates and tolerances helps one gain a cause-and-effect understanding of the role that some environmental (bottom–up) factors play in regulating the seasonality and productivity of key species. We combined the results of laboratory experiments on reproductive success...

  8. The fate of lipids during development and cold-storage of eggs in the laboratory-reared calanoid copepod, Acartia tonsa Dana, and in response to different algal diets

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Bell, J.G.; Sargent, J.R.

    1999-01-01

    composition changes from a tendency towards high levels of long-chain polyunsaturated fatty acids in the early developmental stages towards a tendency to accumulate more saturated and monounsaturated fatty acids in the later developmental stages. However, the content and composition of polyunsaturated fatty......: the cryptophyte Rhodomonas baltica, the haptophyte Isochrysis galbana clone T- iso, the diatom Thalassiosira weissflogii and the dinoflagellate Heterocapsa triquetra. Further, the effect of cold storage of eggs on the lipid composition of the newly hatched nauplii was examined. During development, the fatty acid...... acids can be influenced by the dietary input. The highest ratio of 22:6n - 3/20:5n - 3 was achieved using H, triquetra or I. galbana. Higher levels of 20:5n - 3 were achieved by feeding with R. baltica or T. weissflogii. I. galbana and T. weissflogii were particularly suitable for increasing levels...

  9. Spliced leader RNA trans-splicing discovered in copepods

    Science.gov (United States)

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Yi, Xiaoyan; Huang, Yousong; Chen, Hongju; Lin, Senjie; Campbell, David A.; Sturm, Nancy R.; Liu, Guangxing; Zhang, Huan

    2015-12-01

    Copepods are one of the most abundant metazoans in the marine ecosystem, constituting a critical link in aquatic food webs and contributing significantly to the global carbon budget, yet molecular mechanisms of their gene expression are not well understood. Here we report the detection of spliced leader (SL) trans-splicing in calanoid copepods. We have examined nine species of wild-caught copepods from Jiaozhou Bay, China that represent the major families of the calanoids. All these species contained a common 46-nt SL (CopepodSL). We further determined the size of CopepodSL precursor RNA (slRNA; 108-158 nt) through genomic analysis and 3‧-RACE technique, which was confirmed by RNA blot analysis. Structure modeling showed that the copepod slRNA folded into typical slRNA secondary structures. Using a CopepodSL-based primer set, we selectively enriched and sequenced copepod full-length cDNAs, which led to the characterization of copepod transcripts and the cataloging of the complete set of 79 eukaryotic cytoplasmic ribosomal proteins (cRPs) for a single copepod species. We uncovered the SL trans-splicing in copepod natural populations, and demonstrated that CopepodSL was a sensitive and specific tool for copepod transcriptomic studies at both the individual and population levels and that it would be useful for metatranscriptomic analysis of copepods.

  10. Sensory capabilities and food capture of two small copepods, Paracalanus parvus and Pseudocalanus sp

    DEFF Research Database (Denmark)

    Tiselius, Peter; Saiz, Enric; Kiørboe, Thomas

    2013-01-01

    Detection, handling, and selection of prey are key features of suspension-feeding copepods. Using high-speed video, we determined detection distances and durations of all elements of the food gathering process in two small calanoid copepods, Paracalanus parvus and Pseudocalanus sp. Animals were f...

  11. Host-specific and pH-dependent microbiomes of copepods in an extensive rearing system

    DEFF Research Database (Denmark)

    Skovgaard, Alf; Castro Mejia, Josue Leonardo; Hansen, Lars Hestbjerg;

    2015-01-01

    gradient gel electrophoresis (DGGE) analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which...... furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes....

  12. Copepod flow modes and modulation: a modelling study of the water currents produced by an unsteadily swimming copepod

    OpenAIRE

    2007-01-01

    Video observation has shown that feeding-current-producing calanoid copepods modulate their feeding currents by displaying a sequence of different swimming behaviours during a time period of up to tens of seconds. In order to understand the feeding-current modulation process, we numerically modelled the steady feeding currents for different modes of observed copepod motion behaviours (i.e. free sinking, partial sinking, hovering, vertical swimming upward and horizontal swimming backward or fo...

  13. Checklist of copepods from Gulf of Nicoya, Coronado Bay and Golfo Dulce, Pacific coast of Costa Rica, with comments on their distribution.

    Science.gov (United States)

    Morales-Ramírez, A

    1996-12-01

    A list of 54 copepod species (Crustacea) in 23 families is presented for the Pacific coast of Costa Rica. Identifications are from zooplankton samples of the Victor Hensen Expedition during December 1993 and February 1994. Samples were taken with a Bongo net (0.60 m net opening, 2.50 m net length) with 200 microns mesh size. Oblique hauls were done from the surface to the ground at a towing speed of aprox. 1 knot. 37 species (68.5%) were found in the Gulf of Nicoya, 36 in Golfo Dulce (66.6%) and 17 (31.4%) species were common to both gulfs, while only twelve species (22.2%) were found in Coronado Bay. Four species (7.4%) were distributed along the coast and were common to the three regions: Paracalanus parvus, Euchaeta sp., Oithona plumifera and O. similis. Eleven species of calanoids found normally in the Costa Rica Dome show the influence of typical oceanic waters principally at the mouth of Gulf of Nicoya. Differences were observed in the composition and presence of the copepod species when the inner and outer (upper and lower) parts of both gulfs were compared. Gulf of Nicoya was dominated in its upper part by typical neritic estuarine species like Acartia lilljenborgii, Paracalanus parvus and, Hemyciclops thalassius as well as species of Pseudodiaptomus. On the other hand a more oceanic composition of copepods was observed in the lower part of the gulf. Both small species, like Oncaea venusta, as well as larger species, such as Pleuromamma robusta, Eucalanus attenuatus, E. elongatus and Rhincalanus nasutus, were typical of these waters. Oithona plumifera and O. similis were found in the lower part too; and both species are typical from oceanic water. Coronado Bay was characterized by the presence of typical oceanic species like Neocalanus gracilis, Euchaeta longicornis, Eucalanus attenuatus and Haloptilus ornatus with more transitional species like Clausocalanus pergens and C. furcatus near the coast. In the Golfo Dulce differences in copepod composition were

  14. Hydrodynamic signal perception in the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, E.; Visser, Andre

    1999-01-01

    and the ambient water and may, therefore, be perceived by mechanoreceptory setae. We hypothesised that the threshold value for escape response to a particular component depends solely on the magnitude of the velocity difference (= signal strength) it generates. In experiments we isolated the different components...

  15. Prey switching behaviour in the planktonic copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, E.; Viitasalo, M.

    1996-01-01

    . Based on earlier observations, we also hypothesized that turbulence changes food selection towards motile prey. We tested these hypotheses by examining feeding rates and behaviour in adult females of A. tonsa feeding in mixtures of 2 prey organisms, a diatom (Thalassiosira weissflogii) and a ciliate...... (Strombidium sulcatum). Our data demonstrate prey switching in A. tonsa, both in terms of behaviour and in terms of feeding rates on the alternative prey. The time allocated to ambush and suspension feeding changed with the composition of the food, and clearance of diatoms was, accordingly, negatively related...

  16. Economic feasibility of copepod production for commercial use

    DEFF Research Database (Denmark)

    Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max

    2015-01-01

    condition, reduces mal-pigmentation and allows breeding of ‘new’ marine finfish species. However, copepods are not yet commercially produced and therefore not widely used in the aquaculture industry. One of the bottlenecks for large-scale production has been lack of economic knowledge on the feasibility...... of producing copepods for commercial application. This is the first empirical study to investigate the economic feasibility of copepod production for commercial use. To this end, a standard cost-benefit analysis based on a prototype production facility of Acartia tonsa (Dana) eggs at Roskilde University......, Denmark, is employed. The result reveals that commercial production of copepods is economically feasible considering the existing market prices on both copepods and competing live feed items such as rotifers. The study provides valuable information for businesses who consider investing in live feed...

  17. Seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep – numerical simulations

    Directory of Open Access Journals (Sweden)

    S. Mudrak

    2006-07-01

    Full Text Available A population dynamics model for copepods is presented describing a seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdansk Deep. The copepod model was coupled with an one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate, phytoplankton, microzooplankton and an early juvenile of herring as predator. In this model, mesozooplankton (herbivorous copepods has been introduced as animals having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming, that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth of older stages of 6 cohorts each species to total population biomass. The peaks of copepods biomass, main, at the turn of June and July for Pseudocalanus and smaller, in July for Acartia, lag that phytoplankton by ca. two mouths due to growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdansk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but main development formed after the bloom, in both cases. However, the simulated microzooplankton biomass was enough high to conclude, in our opinion, that, in this case, it was major cause limiting phytoplankton bloom. Model presented here is a next step in understanding how the population dynamics of a dominant species in the southern

  18. Copepod recruitment and food composition : Do diatoms affect hatching success?

    DEFF Research Database (Denmark)

    Jonasdottir, Sigrun; Kiørboe, Thomas

    1996-01-01

    Laboratory experiments were conducted to differentiate between factors controlling the hatching success of copepod eggs. Factors that could affect viability of eggs; viz food quality, female condition and external factors were investigated. In a series of experiments the copepod Acartia tonsa Dana...... was fed several different diets while egg production and hatching success were monitored. The diet was analysed for fatty acid content as an indicator of food quality. Both egg production and hatching were found to be affected by the nutritional quality of the food. Hatching was also highly dependent...

  19. Escape from viscosity : the kinematics and hydrodynamics of copepod foraging and escape swimming

    NARCIS (Netherlands)

    van Duren, LA; Videler, JJ

    2003-01-01

    Feeding and escape swimming in adult females of the calanoid copepod. Temora lopgicornis Muller were investigated and compared. Swimming velocities were calculated using a 3-D filming setup., Foraging velocities ranged between 2 and 6 min s(-1), while maximum velocities of up to 80 mm s(-1) were rea

  20. Reading the copepod personal ads : increasing encounter probability with hydromechanical signals

    NARCIS (Netherlands)

    van Duren, LA; Stamhuis, EJ; Videler, JJ

    1998-01-01

    Females of the calanoid copepod Temora longicornis react to chemical exudates of male conspecifics with little hops, quite distinct from their normal smooth uniform swimming motion. These hops possibly serve to create a hydrodynamical signal in the surrounding water, to increase encounter probabilit

  1. The microbiome of North Sea copepods

    Science.gov (United States)

    Gerdts, G.; Brandt, P.; Kreisel, K.; Boersma, M.; Schoo, K. L.; Wichels, A.

    2013-12-01

    Copepods can be associated with different kinds and different numbers of bacteria. This was already shown in the past with culture-dependent microbial methods or microscopy and more recently by using molecular tools. In our present study, we investigated the bacterial community of four frequently occurring copepod species, Acartia sp., Temora longicornis, Centropages sp. and Calanus helgolandicus from Helgoland Roads (North Sea) over a period of 2 years using DGGE (denaturing gradient gel electrophoresis) and subsequent sequencing of 16S-rDNA fragments. To complement the PCR-DGGE analyses, clone libraries of copepod samples from June 2007 to 208 were generated. Based on the DGGE banding patterns of the two years survey, we found no significant differences between the communities of distinct copepod species, nor did we find any seasonality. Overall, we identified 67 phylotypes (>97 % similarity) falling into the bacterial phyla of Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The most abundant phylotypes were affiliated to the Alphaproteobacteria. In comparison with PCR-DGGE and clone libraries, phylotypes of the Gammaproteobacteria dominated the clone libraries, whereas Alphaproteobacteria were most abundant in the PCR-DGGE analyses.

  2. Seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep – numerical simulations

    Directory of Open Access Journals (Sweden)

    L. Dzierzbicka-Głowacka

    2006-01-01

    Full Text Available A population dynamics model for copepods is presented, describing the seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep. The copepod model was coupled with a one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate, phytoplankton, microzooplankton, and an early juvenile of herring as a predator. In this model, mesozooplankton (herbivorous copepods has been introduced as an animal having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth in the older stages of 6 cohorts of each species, to arrive at a total population biomass. The peaks of copepods' biomass are larger at the turn of June and July for Pseudocalanus and smaller in July for Acartia, lagging that of phytoplankton by ca. two mouths, due to the growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdańsk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but the main development formed after the bloom, in both cases. The phytoplankton bloom is very important in the diet of the adults of the copepods, but it is not particularly important for the youngest part of new generation (early nauplii. However, the simulated microzooplankton biomass was

  3. Bloom-forming cyanobacteria support copepod reproduction and development in the Baltic Sea.

    Science.gov (United States)

    Hogfors, Hedvig; Motwani, Nisha H; Hajdu, Susanna; El-Shehawy, Rehab; Holmborn, Towe; Vehmaa, Anu; Engström-Öst, Jonna; Brutemark, Andreas; Gorokhova, Elena

    2014-01-01

    It is commonly accepted that summer cyanobacterial blooms cannot be efficiently utilized by grazers due to low nutritional quality and production of toxins; however the evidence for such effects in situ is often contradictory. Using field and experimental observations on Baltic copepods and bloom-forming diazotrophic filamentous cyanobacteria, we show that cyanobacteria may in fact support zooplankton production during summer. To highlight this side of zooplankton-cyanobacteria interactions, we conducted: (1) a field survey investigating linkages between cyanobacteria, reproduction and growth indices in the copepod Acartia tonsa; (2) an experiment testing relationships between ingestion of the cyanobacterium Nodularia spumigena (measured by molecular diet analysis) and organismal responses (oxidative balance, reproduction and development) in the copepod A. bifilosa; and (3) an analysis of long term (1999-2009) data testing relationships between cyanobacteria and growth indices in nauplii of the copepods, Acartia spp. and Eurytemora affinis, in a coastal area of the northern Baltic proper. In the field survey, N. spumigena had positive effects on copepod egg production and egg viability, effectively increasing their viable egg production. By contrast, Aphanizomenon sp. showed a negative relationship with egg viability yet no significant effect on the viable egg production. In the experiment, ingestion of N. spumigena mixed with green algae Brachiomonas submarina had significant positive effects on copepod oxidative balance, egg viability and development of early nauplial stages, whereas egg production was negatively affected. Finally, the long term data analysis identified cyanobacteria as a significant positive predictor for the nauplial growth in Acartia spp. and E. affinis. Taken together, these results suggest that bloom forming diazotrophic cyanobacteria contribute to feeding and reproduction of zooplankton during summer and create a favorable growth

  4. Copepod grazing and their impact on phytoplankton standing stock and production in a tropical coastal water during the different seasons

    Digital Repository Service at National Institute of Oceanography (India)

    Jagadeesan, L.; Jyothibabu, R.; Arunpandi, N.; Parthasarathi, S.

    closely related to the hydrographical transformations in the study domain. Dominant calanoid copepods in the study region ingested 8.4 to 14.2% of their daily ration from phytoplankton during the PRM and PSWM, which increased to >50% during the PKSWM...

  5. Rapid enzymatic response to compensate UV radiation in copepods.

    Directory of Open Access Journals (Sweden)

    María Sol Souza

    Full Text Available Ultraviolet radiation (UVR causes physical damage to DNA, carboxylation of proteins and peroxidation of lipids in copepod crustaceans, ubiquitous and abundant secondary producers in most aquatic ecosystems. Copepod adaptations for long duration exposures include changes in behaviour, changes in pigmentation and ultimately changes in morphology. Adaptations to short-term exposures are little studied. Here we show that short-duration exposure to UVR causes the freshwater calanoid copepod, Eudiaptomus gracilis, to rapidly activate production of enzymes that prevent widespread collateral peroxidation (glutathione S-transferase, GST, that regulate apoptosis cell death (Caspase-3, Casp-3, and that facilitate neurotransmissions (cholinesterase-ChE. None of these enzyme systems is alone sufficient, but they act in concert to reduce the stress level of the organism. The interplay among enzymatic responses provides useful information on how organisms respond to environmental stressors acting on short time scales.

  6. Algal toxins alter copepod feeding behavior.

    Directory of Open Access Journals (Sweden)

    Jiarong Hong

    Full Text Available Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod's feeding appendages-a "sampling beating" that has short durations (<100 ms and involves little fluid entrainment and a longer duration "grazing beating" that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod's grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod's feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods.

  7. Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System.

    Directory of Open Access Journals (Sweden)

    Alf Skovgaard

    Full Text Available Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes.

  8. Biochemical composition of copepods for evaluation of feed quality in production of juvenile marine fish

    OpenAIRE

    van der Meeren, Terje; Olsen, Rolf Erik; Hamre, Kristin; Fyhn, Hans Jørgen

    2007-01-01

    To increase current knowledge on the nutritional value of natural prey organisms, the biochemical components of mainly three copepods (Acartia grani, Centropages hamatus, and Eurytemora affinis) from a marine pond system were analysed once a week from spring until late fall, over two years. The analysed components were total lipid, lipid class composition, total lipid fatty acid composition, free amino acids, total protein, protein-bound amino acids, pigment (astaxanthin and ß-carotene), and ...

  9. Development of copepod nauplii to copepodites

    DEFF Research Database (Denmark)

    Andersen, Henrik Rasmus; Wollenberger, Leah; Halling-Sørensen, Bent;

    2001-01-01

    of the 17 test compounds had 50% lethal concentration to 50% effective concentration (EC50) ratios higher than 10. The results suggest that naupliar development, as a parameter, is able to detect hormonal disrupters in addition to other chemicals that have other specific modes of action.......Test compounds including natural hormones, endocrine disrupters, environmentally occurring compounds, and reference compounds were tested for acute toxicity and inhibitory effect on larval development in the copepod Acartia tonsa. Three compounds, 17a-ethinylestradiol, p-octylphenol, and tamoxifen......, known for their differing effects on the vertebrate estrogen system, were potent inhibitors of naupliar development. Other estrogens, 17b-estradiol, estrone, and bisphenol A, had little potency. Testosterone and progesterone did not inhibit development, but the antiandrogen flutamide had inhibitory...

  10. Seasonal variability of planktonic copepods (Copepoda: Crustacea in a tropical estuarine region in Brazil

    Directory of Open Access Journals (Sweden)

    Cristina de Oliveira Dias

    2009-12-01

    Full Text Available The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79. The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and salinity influenced the abundance of species during the rainy and dry seasons, with the following dominant species alternating: Paracalanus quasimodo Bowman, 1971 in the rainy season of 2003, Parvocalanus crassirostris Dahl, 1894 in the dry season of 2003 and Acartia lilljeborgii Giesbrecht, 1892 in the rainy and dry seasons of 2004. Non-parametric multidimensional scaling indicated differences in copepod assemblages between sampling periods, but not between sampling stations.

  11. Variación estacional de la producción de huevos del copépodo calanoideo Centropages furcatus (Dana, 1852 en la Bahía de La Paz, México Seasonal variability of egg production rates of calanoid copepod Centropages furcatus (Dana, 1852 in Bahia de La Paz, Mexico

    Directory of Open Access Journals (Sweden)

    Sergio Hernández-Trujillo

    2008-08-01

    Full Text Available Se estimó la tasa de producción de huevos (TPH para Centropages furcatus en la Bahía de la Paz, Baja California Sur, México, durante 2003. Esta especie es una de las más abundantes y frecuentes de los copépodos en la zona. La estimación en carbono de la producción de huevos fue máxima en verano (1.20 ± 0.7 µg C hembra-¹ d-1 y mínima en primavera (0.58 ± 0.42 µg C hembra-1 d-1. La mayor longitud del prosoma (LP fue registrada en verano (1.15 ± 0.05 mm y la menor en otoño (1.01 ± 0.04 mm. No hubo correlación significativa entre LP y TPH con la concentración de clorofila a (Cl a ni con la temperatura superficial del mar (TSM. En invierno, primavera y verano la TSM fue menor a 23.2 °C, a diferencia de otoño que presentó TSM mayores a 27 °C. En relación a la Cl a, tanto en invierno, primavera y otoño los valores fueron menores a 1 mg m-3, mientras que en verano fueron mayores a 3 mg m-3. Aunque la correlación no fue significativa (p >0.05 entre los parámetros biológicos y las variables ambientales, la especie presentó valores altos de LP y TPH en verano cuando la TSM fue baja y la concentración de Cl a fue la más alta.The egg production rate (EPR was estimated for Centropages furcatus in Bahia de La Paz, Baja California Sur, Mexico during 2003. This species is one of the most abundant and frequent copepod in the zone. The highest egg production in carbon estimations for C. furcatus were observed in summer (1.20 ± 0.7 µg C female-1 d-1 and the lowest was found during spring (0.58 ± 0.42 µg C female-1 d-1. The longest prosome length (PL was registered in summer (1.15 ± 0.05 mm and the shorter during autumn (1.01 ± 0.04 mm. No significant correlation was found in a daily base between EPR and PL with chlorophyll a (Chl a concentration neither the sea surface temperature (SST. In temporal scale, in winter, spring and summer the SST was low (27 °C. Chl a was low (3 mg m-3. Although the correlation was non significant

  12. Feeding on copepod fecal pellets: a new trophic role of dinoflagellates as detritivores

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Moldrup, M.; Berge, T.;

    2011-01-01

    Recent field studies indicate that dinoflagellates are key degraders of copepod fecal pellets. This study is the first to publish direct evidence of pellet grazing by dinoflagellates. Feeding and growth on copepod fecal pellets were studied for both heterotrophic (4 species) and mixotrophic...... dinoflagellates (3 species) using a combination of classic incubation experiments and video recordings of feeding behavior. Fecal pellets were produced by adult Acartia tonsa feeding on Rhodomonas salina. Two mixotrophic species (Karlodinium armiger, a gymnodinoid dinoflagellate, Gy1) and all heterotrophic...... dinoflagellates (Gyrodinium dominans, Gyrodinium spirale, Diplopsalis lenticula, Protoperidinium depressum) studied fed on fecal pellets. Using natural concentrations of dinoflagellates and copepod fecal pellets, average ingestion rates of 0.2 and 0.1 pellets cell−1 d−1 and clearance rates of between 0.2 and 0...

  13. Sex, sex-ratios, and the dynamics of pelagic copepod populations

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2006-01-01

    within this group. Winter population sizes are well predicted by the critical density required for population persistence which, in turn, is closely related to the body-size-dependent mate-search capacity. Thus, the different requirements for mating lead in the first case to a more opportunistic......I examine how the population biology of pelagic copepods depends on their mating biology using field data and a simple demographic model. Among calanoid copepods, two distinct patterns emerge. Firstly, copepods that lack seminal receptacle and require repeated mating to stay fertilized have near...... equal adult sex ratios in field populations. Winter population densities are orders of magnitude less than the critical population density required for population persistence, but populations survive winter seasons as resting eggs in the sediment. Population growth in these species is potentially high...

  14. Mandible characteristics and allometric relations in copepods: a reliable method to estimate prey size and composition from mandible occurrence in predator guts Caracterización de mandíbulas y relación alométrica en copépodos: método adecuado para estimar tamaño y composición de presas usando mandíbulas encontradas en intestinos de depredadores

    Directory of Open Access Journals (Sweden)

    Ricardo Giesecke

    2004-12-01

    Full Text Available The size and shape of the cutting edge of the mandibles from the five most abundant copepod species found in Mejillones Bay are described with the aim to create a helpful tool for the identification of copepod prey and their size from predator gut contents. Good allometric relationships were found between the carapace length and the mandible width for the species Paracalanus parvus, Centropages brachiatus and Acartia tonsa. By contrast, the cyclopoids Oithona sp. and Corycaeus sp. did not present a good relationship between these two parameters, presumably due to the presence of more than a species in the study area. Applying the edge index (Itoh 1970 the copepods were classified as herbivores (e.g., P. parvus, omnivores (e.g., C. brachiatus and A. tonsa, and carnivores (e.g., Oithona sp.. In general, there was a tight relationship between the morphometric characters of the mandible blade and the trophic ecology of each species. The good relationship between the mandible width and the carapace length of the calanoid species will permit the estimation of the size of an ingested copepod by a predator, within a certain degree of accuracy, by measuring the width of the mandibles found in gut contents. This relationship and the supplementary characterization of the mandible blade will help improve the knowledge of the feeding ecology of the mesozooplankton in northern ChileEl tamaño y forma del extremo cortante de la mandíbula de las cinco especies de copépodos más abundantes en la bahía de Mejillones fueron descritas con el propósito de crear una herramienta útil para la identificación de contenidos intestinales de depredadores de copépodos. Aparte de esto, se analizó la relación alométrica entre la longitud cefalotoráxica y el diámetro mandibular para las especies Paracalanus parvus, Centropages brachiatus Acartia tonsa, Oithona sp. y Corycaeus sp. A diferencia de las especies calanoídeas, las especies ciclopoídeas no presentaron

  15. A potential source of recruitment of Acartia pacifica nauplii:viable benthic resting eggs

    Institute of Scientific and Technical Information of China (English)

    WANG Guizhong; JIANG Xiaodong; LI Shaojing; WU Lisheng; WU Dingxun

    2005-01-01

    Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The distribution and abundance of viable resting eggs of Acartia pacifica in the Xiamen Bay were determined by the presence of nauplii in the laboratory. The number of viable eggs varied temporally and spatially. The maximum number (9.2×104m-2) of viable eggs was in summer. In spring the average abundance of viable eggs was 5.6×104 m-2. The abundances of viable eggs in fall and winter were similar, respectively 2.7×104 and 3.3×104 m-2, which were the lowest in the year. The numbers of viable eggs inside the stations of the Xiamen Bay were higher than those outside the stations. The viable eggs were found at all depths (0~10 cm),although not in every station. The maximin number did not necessarily occur in the uppermost centimeter of the sediments but often occurred several centimeters below the water-sediment interface. The accumulation of viable eggs in the seabed of a subtropical bay constitutes a potential source of recruitment of nauplii into the pelagic population.

  16. Zooplankton, especially calanoid copepods, in the upper 1000m of the south-east Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.

    in the samples, namely Macrosetella gracilis, Microsete//fj llon l egica and Aegisthus mucronatus. Of these, M.gracilis was confined to the 308 Zooplankton In the south-east Arabian Sea Table Ill. Relative abundances of various orders ofcopepo....spiniceps, 313 M.Madbupratap and P.Haridas Heterorhabdus spinijrons, Pleuromamma gracilis, P.abdominalis, Phaenna spinifera and Amallothrix indica had higher abundances in the mesopelagic waters. A few other species such as Heterorhabdll.s papilliger, Lucicutia...

  17. Overwintering Strategies of the Calanoid Copepod Calanus plumchrus in a Periodically Anoxic British Columbia Fjord.

    Science.gov (United States)

    1982-10-01

    carbohydrate and 5.4% ash (Ikeda, 1972). The very high proportion of storage lipids (wax esters and triglycerides ), the relatively low proportion of these...discovered that over- wintering C. finmarchicus and C. helgolandicus have a much reduced mid- gut epithelium, low digestive enzyme activities, very low... hydrolysis of the chlorophyll (Strickland and Parsons, 1968). Filters were stored on ice in blackened Jars containing silica gel and then frozen at -20 C

  18. Toxicity Overrides Morphology on Cylindrospermopsis raciborskii Grazing Resistance to the Calanoid Copepod Eudiaptomus gracilis

    NARCIS (Netherlands)

    Machado Rangel, Luciana; Ger, Kemal A.; Silva, Lúcia H.S.; Soares, Maria Carolina S.; Faassen, Els; Lurling, Miguel

    2016-01-01

    Toxicity and morphology may function as defense mechanisms of bloom-forming cyanobacteria against zooplankton grazing. Yet, the relative importance of each of these factors and their plasticity remains poorly known. We tested the effects of chemical and morphological traits of the bloom-forming c

  19. Toxicity Overrides Morphology on Cylindrospermopsis raciborskii Grazing Resistance to the Calanoid Copepod Eudiaptomus gracilis

    NARCIS (Netherlands)

    Rangel, Luciana M.; Ger, Kemal A.; Silva, Lucia H. S.; Soares, Maria Carolina S.; Faassen, Elisabeth J.; Lurling, Miquel

    2016-01-01

    Toxicity and morphology may function as defense mechanisms of bloom-forming cyanobacteria against zooplankton grazing. Yet, the relative importance of each of these factors and their plasticity remains poorly known. We tested the effects of chemical and morphological traits of the bloom-forming cyan

  20. A parameter for detecting estrogenic exposure in the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Andersen, Henrik Rasmus; Halling-Sørensen, Bent; Kusk, Kresten Ole

    1999-01-01

    estrogenic than 17 beta-estradiol, the nonestrogen 2,3-dichlorophenole was tested at 13.6 mu g/L (molar concentration equal to 23 mu g/L 17 beta-estradiol) to test if the response is a general nonestrogenic toxic stress effect. The 2,3-dichlorophenole produced no effect. (C) 1999 Academic Press....

  1. Predatory and suspension feeding of the copepod Acartia tonsa in turbulent environments

    DEFF Research Database (Denmark)

    Saiz, E.; Kiørboe, Thomas

    1995-01-01

    )) was generated by an oscillating grid. In ambush feeding mode, low (realistic) intensities of turbulence (epsilon = 10(-3) to 10(-2) cm(2) s(- 3)) enhanced clearance rates by up to a factor of 4 above those observed in calm water. Higher intensities of turbulence (epsilon = 10(-1) to 10(1) cm(2) s(-3)) resulted...... of the 2 feeding behaviours, including the negative effects, were accurately predicted by encounter rate and feeding behaviour models proposed by Kiorboe and Saiz (1995; Mar Ecol Frog Ser 122:135-145). Because feeding behaviour is specific to the prey (phytoplankton vs motile prey), and because ambush...... it is numerically scarce relative to phytoplankton in the environment...

  2. Morphometric differences in two calanoid sibling species, Boeckella gracilipes and B. titicacae (Crustacea, Copepoda

    Directory of Open Access Journals (Sweden)

    Patricio De los Ríos Escalante

    2012-12-01

    Full Text Available Calanoid copepods are abundant in South American inland waters and include widespread species, such as Boeckella gracilipes (Daday, 1902, which occurs from the Ecuador to Tierra del Fuego Island. This species occurs under various environmental conditions, and is found in oligotrophic lakes in Patagonia (39-54°S and in shallow mountain lakes north of 39°S. The aim of the present study is to conduct a morphometric comparison of male specimens of B. titicacae collected in Titicaca and B. gracilipes collected in Riñihue lakes, with a third population of B. gracilipes collected in shallow ponds in Salar de Surire. Titicaca and Riñihue lakes are stable environments, whereas Salar de Surire is an extreme environment. These ponds present an extreme environment due to high exposure to solar radiation and high salinity levels. The results of the study revealed differences among the three populations. These results agree well with systematic descriptions in the literature on differences between the populations of Titicaca and Riñihue lakes, and population of Salar de Surire differs slightly from the other two populations. It is probable that the differences between the population of Salar de Surire and the other two populations result from the extreme environment in Salar de Surire. High exposure to solar radiation, high salinity and extreme variations in temperature enhance genetic variations that are consequently expressed in morphology.

  3. Biological processes in the North Sea: vertical distribution and reproduction of neritic copepods in relation to environmental factors

    DEFF Research Database (Denmark)

    Koski, Marja; Jonasdottir, Sigrun; Bagøien, Espen

    2011-01-01

    observed a higher egg production of cultured Acartia tonsa when fed with the seston from chlorophyll maximum, but no evidence of a higher copepod abundance in this layer. Secondary production was highest at the station closest to the upwelling of new nutrients, although seasonal differences...... for reproduction compared with surface waters and (iii) if the secondary production is thus higher in the frontal areas with a subsurface chlorophyll maximum. In addition, we wanted to (iv) identify the most important environmental factors determining the reproduction of neritic copepods in the North Sea. We...... in environmental variables probably overrode the differences between frontal and stratified stations. Copepod egg production on an annual basis seemed to be best predicted by the body size and specific fatty acids, with a high egg production, but low hatching success associated with a high EPA:DHA ratio. Total...

  4. Spatial distribution of copepods along the salinity gradient of Perai river estuary, Penang, Malaysia.

    Science.gov (United States)

    Johan, I; Maznah, W O Wan; Mashhor, M; Abu Hena, M K; Amin, S M N

    2012-07-01

    Investigation on copepod communities in Perai river estuary was conducted from November 2005 to May 2006. Five stations were established for monthly sampling and were located from the river mouth to the upper reaches of the river. Copepod samples were collected from vertical tows using a standard zooplankton net. The Perai river estuary was slightly stratified and salinity decreases significantly from the mouth of the river towards the upper reaches of the river. A total of 28 species of copepods were recorded and comprised of 14 families, Paracalanidae, Oithonidae, Corycaeidae, Acartiidae, Calanidae, Centropagidae, Eucalanidae, Pontellidae, Pseudodiaptomidae, Tortanidae, Ectinosomatidae, Euterpinidae, Clausidiidae and Cyclopidae. A total of 10 species showed high positive affiliation towards salinity (R > 0.60), Acartia spinicauda, Euterpina acutifrons, Microsetella norvegica, Oithona nana, Oithona simplex, Paracalanus crassirostris, Paracalanus elegans, Paracalanus parvus, Pseudodiaptomus sp. and Hemicyclops sp. The copepod species Pseudodiaptomus dauglishi were negatively affiliated towards salinity (R = -0.71). The copepod assemblages classified into two distinct groups according to salinity regimes, euryhaline-polyhaline group (25 marine affiliated species) and oligohaline-mesohaline group (3 freshwater affiliated species).

  5. Seasonal change in body length of important small copepods and relationship with environmental factors in Jiaozhou Bay,China

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaohong; SUN Song; LI Chaolun; WANG Minxiao

    2012-01-01

    Differences among species in prosome length and in species' response to environmental factors do exist.Therefore,it is useful to examine prosome length for different copepod species in variable environments.Seasonal variations in prosome length of four small copepods and their copepodite stages in the Jiaozhou Bay were compared and the relative influence of temperature,salinity,and chlorophyll concentration were examined.Two peaks were found in the mean prosome length of Paracalanusparvus (in early winter and May).For Acartia bifilosa,the maximum values of all copepodites occurred mainly from February to April,and decreased to the bottom in July.Prosome length of Acartia pacifica peaked when it first appeared in June,then reached to the minimum in July.Parvocalanus crassirostris only appeared from late summer to autumn and the mean prosome length showed no clear changes.Correlations of adult prosome length with environmental factors were evaluated.For the four species,temperature was negatively correlated to prosome length except for P.crassirostris.But the different species varied markedly in their responds to temperature.A.bifilosa showed a more definite trend of size variation with temperature than P.parvus and A.pacifica.Correlations of prosome length with salinity were significantly positive for almost all the small copepods.The relationship between chlorophyll concentration and prosome length was complicated for these copepods,but for P.parvus,chlorophyll concentration was also an important affecting factor.Furthermore,investigation needs to be done on food quality for some copepod.These results are essential to estimate the biomass and the production,and to understand these small copepods' population dynamics in this human-affected bay.

  6. Life-stage-specific differences in exploitation of food mixtures: diet mixing enhances copepod egg production but not juvenile development

    DEFF Research Database (Denmark)

    Koski, Marja; Breteler, W.K.; Schogt, N.;

    2006-01-01

    Development, egg production and hatching success of the calanoid copepods Temora longicornis and Pseudocalanus elongatus were measured in food mixtures to test their ability to obtain a complete nutrition by combining different nutritionally poor food species. In all the food mixtures used......, the copepods failed to moult past the first copepodite stage, and the mortality was high. In sharp contrast, mixing two nutritionally poor food species often resulted in egg production which was not significantly different from nutritionally high quality food, although hatching success in many mixtures was low...... mortality were, however, independent of either nitrogen or HUFAs in the diet. Our results show that adult copepods are effective in combining their nutrition from several food sources, whereas juveniles are not. We suggest that there are species- and life-stage-specific differences in nutritional...

  7. How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods.

    Science.gov (United States)

    Almeda, Rodrigo; Connelly, Tara L; Buskey, Edward J

    2016-01-01

    We investigated and quantified defecation rates of crude oil by 3 species of marine planktonic copepods (Temora turbinata, Acartia tonsa, and Parvocalanus crassirostris) and a natural copepod assemblage after exposure to mechanically or chemically dispersed crude oil. Between 88 and 100% of the analyzed fecal pellets from three species of copepods and a natural copepod assemblage exposed for 48 h to physically or chemically dispersed light crude oil contained crude oil droplets. Crude oil droplets inside fecal pellets were smaller (median diameter: 2.4-3.5 μm) than droplets in the physically and chemically dispersed oil emulsions (median diameter: 6.6 and 8.0 μm, respectively). This suggests that copepods can reject large crude oil droplets or that crude oil droplets are broken into smaller oil droplets before or during ingestion. Depending on the species and experimental treatments, crude oil defecation rates ranged from 5.3 to 245 ng-oil copepod(-1) d(-1), which represent a mean weight-specific defecation rate of 0.026 μg-oil μg-Ccopepod(1) d(-1). Considering a dispersed crude oil concentration commonly found in the water column after oil spills (1 μl L(-1)) and copepod abundances in high productive coastal areas, copepods may defecate ∼ 1.3-2.6 mg-oil m(-3) d(-1), which would represent ∼ 0.15%-0.30% of the total dispersed oil per day. Our results indicate that ingestion and subsequent defecation of crude oil by planktonic copepods has a small influence on the overall mass of oil spills in the short term, but may be quantitatively important in the flux of oil from surface water to sediments and in the transfer of low-solubility, toxic petroleum hydrocarbons into food webs after crude oil spills in the sea.

  8. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    Directory of Open Access Journals (Sweden)

    R. Kiko

    2015-10-01

    Full Text Available Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ. At depth, the animals experience reduced temperature and oxygen partial pressure (pO2 and an increased carbon dioxide partial pressure (pCO2 compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2 and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply considerably fuels bacterial anaerobic ammonium oxidation – a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2 does not result in a downregulation of ammonium excretion. Here we show that exposure to OMZ conditions can result in strong depression of respiration and ammonium excretion in calanoid copepods and euphausiids from the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These physiological responses need to be taken into account when estimating DVM-mediated fluxes of carbon and nitrogen into OMZs.

  9. Prey detection and prey capture in copepod nauplii.

    Directory of Open Access Journals (Sweden)

    Eleonora Bruno

    Full Text Available Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae and by the nauplii of one feeding-current feeding species (Temora longicornis. We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey.

  10. Composition of the zooplankton community, with emphasis in copepods, in Punta Morales, Golfo De Nicoya, Costa Rica.

    Science.gov (United States)

    Brugnoli-Olivera, Ernesto; Díaz-Ferguson, Edgardo; Delfino-Machin, Mariana; Morales-Ramírez, Alvaro; Arosemena, Arturo Dominici

    2004-12-01

    The composition of the mesozooplanktonic community was studied in the Punta Morales estuary, Gulf of Nicoya, Pacific coast of Costa Rica, during 1997. Oblique plankton hauls were performed during high and low tide using a 280 microm mesh screen net equipped with a flowmeter. The community was characterized by holoplanktonic and meroplanktonic organisms. For the holoplanktonic community, the main groups were copepods (80%) and chaetognaths (16%). The most abundant species were the copepods Acartia lilljeborgii and Paracalanus parvus. A. lilljeborgii is a typical estuarine species that maintains high populations in estuarine systems. Meroplankton was represented mainly by crustacean larvae (66%), and icthyoplankton (18%). The dominance of crustacean larvae and icthyoplankton is an evidence of the ecological importance of the Punta Morales zone.

  11. Fitness consequences for copepods feeding on a red tide dinoflagellate: deciphering the effects of nutritional value, toxicity, and feeding behavior.

    Science.gov (United States)

    Prince, Emily K; Lettieri, Liliana; McCurdy, Katherine J; Kubanek, Julia

    2006-03-01

    Phytoplankton exhibit a diversity of morphologies, nutritional values, and potential chemical defenses that could affect the feeding and fitness of zooplankton consumers. However, how phytoplankton traits shape plant-herbivore interactions in the marine plankton is not as well understood as for terrestrial or marine macrophytes and their grazers. The occurrence of blooms of marine dinoflagellates such as Karenia brevis suggests that, for uncertain reasons, grazers are unable to capitalize on, or control, this phytoplankton growth-making these systems appealing for testing mechanisms of grazing deterrence. Using the sympatric copepod Acartia tonsa, we conducted a mixed diet feeding experiment to test whether K. brevis is beneficial, toxic, nutritionally inadequate, or behaviorally rejected as food relative to the palatable and nutritionally adequate phytoplankter Rhodomonas lens. On diets rich in K. brevis, copepods experienced decreased survivorship and decreased egg production per female, but the percentage of eggs that hatched was unaffected. Although copepods showed a 6-17% preference for R. lens over K. brevis on some mixed diets, overall high ingestion rates eliminated the possibility that reduced copepod fitness was caused by copepods avoiding K. brevis, leaving nutritional inadequacy and toxicity as remaining hypotheses. Because egg production was dependent on the amount of R. lens consumed regardless of the amount of K. brevis eaten, there was no evidence that fitness costs were caused by K. brevis toxicity. Copepods limited to K. brevis ate 480% as much as those fed only R. lens, suggesting that copepods attempted to compensate for low food quality with increased quantity ingested. Our results indicate that K. brevis is a poor food for A. tonsa, probably due to nutritional inadequacy rather than toxicity, which could affect bloom dynamics in the Gulf of Mexico where these species co-occur.

  12. Fitness costs and benefits of ultraviolet radiation exposure in marine pelagic copepods

    DEFF Research Database (Denmark)

    Hylander, Samuel; Grenvald, Julie Cornelius; Kiørboe, Thomas

    2014-01-01

    Life-history theory predicts that organisms should allocate energy throughout their life such that they maximize their fitness. Copepod zooplankton are known to accumulate sunscreens (so-called mycosporine-like amino acids, MAAs) and antioxidant carotenoids to mitigate negative effects of ultravi......Life-history theory predicts that organisms should allocate energy throughout their life such that they maximize their fitness. Copepod zooplankton are known to accumulate sunscreens (so-called mycosporine-like amino acids, MAAs) and antioxidant carotenoids to mitigate negative effects...... of ultraviolet radiation (UVR), but it is not well known how this affects their fitness. We followed cohorts of the marine copepod Acartia tonsa and assessed how fitness was affected by UVR exposure and a diet rich in UVR-protective sunscreens. Several fitness components including somatic growth, egg quality...... and nauplii production (larvae) were negatively affected by UVR, whereas other components such as size at maturity, survival and length of life were not. Nauplii production through low egg quality was the most influential life-history parameter that changed in response to UVR. There was interaction between...

  13. Population genetics of drifting (Calanus spp.) and resident (Acartia clausi) plankton in Norwegian fjords

    Digital Repository Service at National Institute of Oceanography (India)

    Bucklin, A.; Kaartvedt, S.; Guarnieri, M.; Goswami, U.

    rRNA, population genetic diversity and structure in drifting populations of Calanus spp. with that of resident populations of Acartia clausi is contrasted. With the exception of Sorfjorden (where Calanus spp. were rare), two or three species...

  14. First report of ciliate (Protozoa) epibionts on deep-sea harpacticoid copepods

    Science.gov (United States)

    Sedlacek, Linda; Thistle, David; Fernandez-Leborans, Gregorio; Carman, Kevin R.; Barry, James P.

    2013-08-01

    We report the first observations of ciliate epibionts on deep-sea, benthic harpacticoid copepods. One ciliate epibiont species belonged to class Karyorelictea, one to subclass Suctoria, and one to subclass Peritrichia. Our samples came from the continental rise off central California (36.709°N, 123.523°W, 3607 m depth). We found that adult harpacticoids carried ciliate epibionts significantly more frequently than did subadult copepodids. The reason for the pattern is unknown, but it may involve differences between adults and subadult copepodids in size or in time spent swimming. We also found that the ciliate epibiont species occurred unusually frequently on the adults of two species of harpacticoid copepod; a third harpacticoid species just failed the significance test. When we ranked the 57 harpacticoid species in our samples in order of abundance, three species identified were, as a group, significantly more abundant than expected by chance if one assumes that the abundance of the group and the presence of ciliate epibionts on them were uncorrelated. High abundance may be among the reasons a harpacticoid species carries a ciliate epibiont species disproportionately frequently. For the combinations of harpacticoid species and ciliate epibiont species identified, we found one in which males and females differed significantly in the proportion that carried epibionts. Such a sex bias has also been reported for shallow-water, calanoid copepods.

  15. The kinematics of swimming and relocation jumps in copepod nauplii.

    Directory of Open Access Journals (Sweden)

    Christian Marc Andersen Borg

    Full Text Available Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and copepodites are equipped with highly specialized swimming legs. In some species the nauplius may also propel itself more slowly through the water by beating and rotating the appendages in a different, more complex pattern. We use high-speed video to describe jumping and swimming in nauplii of three species of pelagic copepods: Temora longicornis, Oithona davisae and Acartia tonsa. The kinematics of jumping is similar between the three species. Jumps result in a very erratic translation with no phase of passive coasting and the nauplii move backwards during recovery strokes. This is due to poorly synchronized recovery strokes and a low beat frequency relative to the coasting time scale. For the same reason, the propulsion efficiency of the nauplii is low. Given the universality of the nauplius body plan, it is surprising that they seem to be inefficient when jumping, which is different from the very efficient larger copepodites. A slow-swimming mode is only displayed by T. longicornis. In this mode, beating of the appendages results in the creation of a strong feeding current that is about 10 times faster than the average translation speed of the nauplius. The nauplius is thus essentially hovering when feeding, which results in a higher feeding efficiency than that of a nauplius cruising through the water.

  16. Copepods of the nearshore waters of Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Stephen, R.; Nair, V.R.; Desai, B.N.

    towards the shore during the flood period and an reverse pattern during the ebb period. Sixty eight species were recorded from the area. Acartia spinicauda, Acrocalanus similis and Paracalanus crassirostris were the most common species. Species assemblage...

  17. Predation by the Dwarf Seahorse on Copepods: Quantifying Motion and Flows Using 3D High Speed Digital Holographic Cinematography - When Seahorses Attack!

    Science.gov (United States)

    Gemmell, Brad; Sheng, Jian; Buskey, Ed

    2008-11-01

    Copepods are an important planktonic food source for most of the world's fish species. This high predation pressure has led copepods to evolve an extremely effective escape response, with reaction times to hydrodynamic disturbances of less than 4 ms and escape speeds of over 500 body lengths per second. Using 3D high speed digital holographic cinematography (up to 2000 frames per second) we elucidate the role of entrainment flow fields generated by a natural visual predator, the dwarf seahorse (Hippocampus zosterae) during attacks on its prey, Acartia tonsa. Using phytoplankton as a tracer, we recorded and reconstructed 3D flow fields around the head of the seahorse and its prey during both successful and unsuccessful attacks to better understand how some attacks lead to capture with little or no detection from the copepod while others result in failed attacks. Attacks start with a slow approach to minimize the hydro-mechanical disturbance which is used by copepods to detect the approach of a potential predator. Successful attacks result in the seahorse using its pipette-like mouth to create suction faster than the copepod's response latency. As these characteristic scales of entrainment increase, a successful escape becomes more likely.

  18. Influence of phytoplankton diets on the ingestion rate and egg production of Acartia clausi and A. lilljeborgii (Copepoda: Calanoida from Bahía de La Paz, Gulf of California Influencia de dietas de fitoplancton en la tasa de ingesta y producción de huevos de Acartia clausi y A. lilljeborgii (Copepoda: Calanoida de la Bahía de La Paz, Golfo de California

    Directory of Open Access Journals (Sweden)

    Christine Johanna Band-Schmidt

    2008-08-01

    Full Text Available Different phytoplankton diets were tested on Acartia clausi and A. lilljeborgii from Bahía de La Paz to determine their effect on survival, egg production, and ingestion rate. Female copepods were fed diatom strains (Chaetoceros sp., Cylindrotheca closterium, Odontella longicruris, and Dytilum brightwelli, dinoflagellate strains (Scrippsiella sp., Gyrodinium sp., Prorocentrum micans, and P. rhathymum, and one Raphidophyceae (Chattonella sp.. After 24 h of incubation in darkness at 24 °C, survival with various phytoplankton diets was above 91%. Gyrodinium sp. produced the lowest survival in both copepod species (44.5% in A. clausi and 89.6% in A. lilljeborgii. Dinoflagellate diets provided the highest egg production. A. clausi had higher egg production when fed with P. rhathymum, P. micans, Gyrodinium sp., Scrippsiella sp., and Chattonella sp. A. lilljeborgii had a higher egg production with Scrippsiella sp., P. micans, Gyrodinium sp., and Chaetoceros sp. Ingestion rates were higher in both Acartia species with two diatom diets (O. longicruris and Chaetoceros sp., P. rhathymum and Chattonella sp. These results suggest that both Acartia species respond to nutritional quality of phytoplankton in a short time. Higher ingestion rates did not necessarily result in higher egg production, suggesting that the link between ingestion and egg production may be in what is eaten, rather than in how much. The response in egg production seems to be species specific, but in general was higher with dinoflagellate diets, suggesting a higher food quality compared with diatoms (excepting Chaetoceros sp..Se probaron diversas dietas de fitoplancton en Acartia clausi y A. lilljeborgii de la Bahía de La Paz, para determinar su efecto en la supervivencia, producción de huevos y tasa de ingesta. Se alimentaron hembras de copépodos con cepas de diatomeas (Chaetoceros sp., Cylindrotheca closterium, Odontella longicruris y Dytilum brightwelli, de dinoflagelados

  19. First record of the Calanoid Copepod Pseudodiaptomus serricaudatus (Scott, T. 1894), (Copepoda: Calanoida: Pseudodiaptomidae) in the equatorial Indian ocean.

    Digital Repository Service at National Institute of Oceanography (India)

    Rebello, V.; Narvekar, J.; Gadi, P.; Venenkar, A.; Gauns, M.; PrasannaKumar, S.

    region; the most frequently observed phytoplankton species were Coscinodiscus sp., Thalassiosira sp., Navicula sp., Gonyaulax sp. and Protoperidinium sp. At station E1 the phytoplankton such as Cerataulina sp., Dactyliosolen sp., Leptocylindrus sp...., Rhizosolenia sp., Lioloma sp., Gonyaulax sp., Guinardia sp. and Protoperidinium sp. were the most abundant forms (Supplementary Table 1). Fig. 3. Mean monthly salinity (psu) from World Ocean Atlas (WOA-09) superimposed...

  20. Some species of calanoid copepods recently described from Indonesian waters with notes on their distribution and species-groups

    Directory of Open Access Journals (Sweden)

    Mulyadi Mulyadi

    2000-12-01

    Full Text Available One species of the family Candaciidae, Candaciaishimarui, and four species of the family Pontellidae, Calanopiaasymmetrica, Labidocerajavaensis, L. muranoi, and Pontellalabuanensis were described from specimens collected from the Indonesian waters. C. ishimarui belong to C. norvegica group, which was hitherto composed of 3 species, C. ketchumi Grice 1961, and C. norvegica (Boeck, 1865, by having common characters of the maxilla-shape, the 3 cups of basal mandibular tooth, and the structure of P5 in both sexes. C. asymmetrica, with belong to C. herdmani group, the character of the CR and P5. L. javaensis is distinguishable from the L. pectinaya group by the shape of genital complex and he P5 in the male. It seems to be a neritic species inhabiting coastal waters shallower than 15 m in depth, and with 0.5 km off-shore. L. muranoi which was collected from Cilacap Bay. Belongs to the L. kroyeri group, and was distinguished from other species of this group by the shape of urosome and P5 in the female and by Ms5 and P5 in the male. The last described species, P. labuanensisdoes not belong to anu of the known 3 species-groups of indo-West Pacific Pontella, in having the asymmetrical genital somite and the Re's of the P5 virtually naked in the female, and the rostrum with double convex lenses and the Re's of the male with P5 with 2 subequal dumb.

  1. Improving cold storage of subitaneous eggs of the copepod Acartia tonsa Dana from the Gulf of Mexico (Florida, USA)

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Lindley, L.C.; Michels, A.

    2007-01-01

    . We consider that the use of antibiotics at the right dosage to be a means to increase the storage capacity of the Gulf of Mexico strain of A. tonsa eggs, which do not show any capacity to be stored for long periods of time, compared with some other strains. In addition eggs that were between 5 and 7...

  2. Effects of methyltestosterone, letrozole, triphenyltin and fenarimol on histology of reproductive organs of the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Watermann, Burkard T.; Albanis, Triantafyllos A.; Dagnac, Thierry

    2013-01-01

    and displayed deformations. In females, LET induced a disorder of oogenesis and disturbances in yolk synthesis. TPT stimulated the male reproductive system at 0.0014 and 0.0035μg TPT-SnL−1, whereas inhibiting effects were observed in the female gonad at 0.0088μg TPT-SnL−1. In FEN exposed females proliferation......, or the musculature were seen. This indicates that the effects on gonads might be caused rather by disturbance of endocrine signalling or interference with hormone metabolism than by general toxicity....

  3. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    Science.gov (United States)

    Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

    2016-04-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2, and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

  4. Epibionts and parasites on crustaceans (Copepoda, Cladocera, Cirripedia larvae inhabiting the Gulf of Gdańsk (Baltic Sea in very large numbers

    Directory of Open Access Journals (Sweden)

    Luiza Bielecka

    2014-06-01

    Full Text Available The occurrence of epizoic filter-feeding Protozoa (Vorticella and Zoothamnium and parasitic Protozoa (Ellobiopsis on Calanoida was noticed in the Gulf of Gdańsk in 1998, 1999 and 2006. The relatively high (4-16% of all calanoids level of infestation varied depending on the type of infestation (0.1-13% of the population of particular taxa. The dominant copepodsAcartia spp., Temora longicornis and Centropages hamatus - were attacked the most frequently (from 10.5% to 54% of all infested calanoids. Epibiosis and parasitism were observed on all copepod developmental stages (adults, juveniles and nauplii. Epibionts and parasites were located on different parts of the body, but mainly on the prosome. Infestation by epibionts and parasites was not restricted to calanoid copepods: it was also detected in non-negligible numbers on other crustaceans, namely, Harpacticoida, Cladocera (Bosmina sp. and Cirripedia larvae (nauplii in the Gulf of Gdańsk.

  5. The turbidity front as a habitat for Acartia tonsa (Copepoda) in the Río de la Plata, Argentina-Uruguay

    Science.gov (United States)

    Derisio, Carla; Braverman, Mara; Gaitán, Esteban; Hozbor, Constanza; Ramírez, Fernando; Carreto, José; Botto, Florencia; Gagliardini, Domingo A.; Acha, E. Marcelo; Mianzan, Hermes

    2014-01-01

    Acartia tonsa is one of the most abundant copepod species in estuaries worldwide. In the Río de la Plata, its highest densities appear to occur in an area of low quality food (detritus): the turbidity front (TF). The objective of this study was to understand how trophic and oceanographic drivers contribute to the high densities of A. tonsa in the Río de la Plata TF. The patterns of spatial distribution and density of this species were analyzed in relation to oceanographic and biological attributes of the system. The egg production rate (EPR) in the TF was evaluated as a measure of fitness, and a stable isotope analysis indicated the possible sources of organic matter in the species' diet. This study confirmed that the highest observed densities of A. tonsa were mostly associated with the TF, where high suspended matter and low Chl-a occur. Immediately offshore from the TF, decreased copepod densities and the maximum Chl-a values were found. Females close to the estuarine turbidity maximum (ETM) had a lower EPR than those closer to the high Chl-a concentrations. Within the TF, A. tonsa apparently fed on detritus close to the ETM and phytoplankton close to the edge of the TF. The report includes a discussion of how retention processes, two layered flow and the life history strategy of A. tonsa could be contributing to the development of high densities (more than 10,000 ind m- 3) of this species in the inner estuarine zone, despite the poor quality of food available for development in that area. A. tonsa can live and prosper in areas with high turbidity and low chlorophyll concentrations. This trait exemplifies the plasticity of this species and helps explain why it is a key species in many worldwide estuaries.

  6. Population dynamics of four dominant copepods in Prydz Bay, Antarctica, during austral summer from 1999 to 2006

    Institute of Scientific and Technical Information of China (English)

    YANG Guang; LI Chaolun; SUN Song

    2011-01-01

    Population dynamics of four dominant Antarctic copepods,Calanoides acutus,Calanus propinquus,Metridia gerlachei and Rhincalanus gigas were studied based on zooplankton samples collected in the Prydz Bay during austral summer from 1999 to 2006.We found that C.acutus was the most abundant species among these four copepods,followed by C.propinquus,M.gerlachei and R.gigas.R.gigas occurred mainly in the warmer oceanic regions and showed distribution pattems discrete from the other three species,whose distribution in the whole survey area overlapped.By December 15th (about one month before our sampling) of the years 1999,2003 and 2006,sea ice retreated earlier and polynyas existed in the neritic region one month before sampling.These periods were characterized by numerical dominance of C.acutus,C.propinquus and M.gerlachei,elevated proportions of Copepodite Ⅰ and Copepodite Ⅱ stages especially in the neritic region.While for the years 2000,2002,and 2005,the ice edge located more northerly and polynyas did not exist in the neritic region,the copepods abundance was lower,indicating poor recruitment.Population structure of R.gigas was mainly composed of advanced stages Copepodite V and female during all cruises.Log10 (x+l) transformed densities of C.acutus,C.propinquus and M.gerlachei showed positive correlation with temperature and chlorophyll a concentration,while mean population stages of these copopods were negatively correlated with these environmental variables.Younger copepodite stages of C.acutus,C.propinquus and M.gerlachei appeared more often in neritic regions.We confirmed that the polynyas had a great contribution to phytoplankton blooms,which promote copepods reproduction and recruitment success.The study suggested that population dynamics of the four copepods have good correspondence with sea ice and polynya variations during all cruises of the Prydz Bay.

  7. Short-term changes of the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn

    Science.gov (United States)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-03-01

    In the Chukchi Sea, due to the recent drastic reduction of sea-ice during the summer, an increasing formation of atmospheric turbulence has been reported. However, the importance and effects of atmospheric turbulence on the marine ecosystem are not fully understood in this region. To evaluate the effect of atmospheric turbulence on the marine ecosystem, high-frequent sampling (two to four times per day) on the mesozooplankton community and the gut pigment of dominant copepods were made at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the standing stock of chlorophyll a (chl a) was increased, especially for micro-size (> 10 μm) fractions. Zooplankton abundance ranged 23 610-56 809 ind. m-2 and exhibited no clear changes with SWE. In terms of abundance, calanoid copepods constituted the most dominated taxa (mean: 57%), followed by barnacle larvae (31%). Within the calanoid copepods, small-sized Pseudocalanus spp. (65%) and large-sized Calanus glacialis (30%) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient chl a, and a significant increase was observed after SWE (2.6 vs. 4.5 ng pigment ind.-1). Assuming C : Chl a ratio, the grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6% of the standing stock of micro-size phytoplankton. Compared with the metabolic food requirement, their feeding on phytoplankton accounted for 12.6% of their total food requirement. These facts suggest that C. glacialis could not maintain their population on solely phytoplankton food, and other food sources (i

  8. The chemical ecology of copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Selander, Erik

    2014-01-01

    for the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of signal...... molecules. The review illustrates the importance of chemical interactions in many aspects of copepod ecology and identifies gaps in our knowledge, such as the lack of identified infochemicals and electrophysiological studies to confirm the function of sensory structures. We suggest approaches...

  9. Towards an internationally harmonized test method for reproductive and developmental effects of endocrine disrupters in marine copepods

    DEFF Research Database (Denmark)

    Kusk, Kresten Ole; Wollenberger, Leah

    2007-01-01

    New and updated methods to detect and characterize endocrine disrupting chemicals (EDCs) are urgently needed for the purpose of environmental risk assessment since these substances are often not detected using existing chronic toxicity tests. Numerous reports on the effects of EDCs on crustacean...... development and reproduction have been published and the development of life-cycle tests with crustaceans has been prioritized within the OECD work program for endocrine disrupter testing and assessment. As a result, Sweden, and Denmark initiated a proposal for development of a full life-cycle test...... with marine copepods (Acartia tonsa, Nitocra spinipes, Tisbe battagliai, and Amphiascus tenuiremis). The present paper gives an overview on the endocrine system of crustaceans with special emphasis on development and reproduction, which are targets for endocrine disruption, and reviews available methods...

  10. The chemical ecology of copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Selander, Erik

    2014-01-01

    for the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of signal...

  11. What makes pelagic copepods so successful?

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2011-01-01

    Three features that are unique or almost unique to pelagic copepods among zooplankton may account for their numerical dominance in the pelagic realm of the oceans: (i) the torpedo-shaped body, the sensory armed antennules and the ‘gearing’ of the muscle motor make pelagic copepods very efficient...

  12. Spliced leader-based analyses reveal the effects of polycyclic aromatic hydrocarbons on gene expression in the copepod Pseudodiaptomus poplesia.

    Science.gov (United States)

    Zhuang, Yunyun; Yang, Feifei; Xu, Donghui; Chen, Hongju; Zhang, Huan; Liu, Guangxing

    2017-02-01

    Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic and carcinogenic pollutants that can adversely affect the development, growth and reproduction of marine organisms including copepods. However, knowledge on the molecular mechanisms regulating the response to PAH exposure in marine planktonic copepods is limited. In this study, we investigated the survival and gene expression of the calanoid copepod Pseudodiaptomus poplesia upon exposure to two PAHs, 1, 2-dimethylnaphthalene (1, 2-NAPH) and pyrene. Acute toxicity responses resulted in 96-h LC50 of 788.98μgL(-1) and 54.68μgL(-1) for 1, 2-NAPH and pyrene, respectively. Using the recently discovered copepod spliced leader as a primer, we constructed full-length cDNA libraries from copepods exposed to sublethal concentrations and revealed 289 unique genes of diverse functions, including stress response genes and novel genes previously undocumented for this species. Eighty-three gene families were specifically expressed in PAH exposure libraries. We further analyzed the expression of seven target genes by reverse transcription-quantitative PCR in a time-course test with three sublethal concentrations. These target genes have primary roles in detoxification, oxidative defense, and signal transduction, and include different forms of glutathione S-transferase (GST), glutathione peroxidases (GPX), peroxiredoxin (PRDX), methylmalonate-semialdehyde dehydrogenase (MSDH) and ras-related C3 botulinum toxin substrate (RAC1). Expression stability of seven candidate reference genes were evaluated and the two most stable ones (RPL15 and RPS20 for 1, 2-NAPH exposure, RPL15 and EF1D for pyrene exposure) were used to normalize the expression levels of the target genes. Significant upregulation was detected in GST-T, GST-DE, GPX4, PRDX6 and RAC1 upon 1, 2-NAPH exposure, and GST-DE and MSDH upon pyrene exposure. These results indicated that the oxidative stress was induced and that signal transduction might be affected by PAH

  13. Copepod response to ocean acidification in a low nutrient-low chlorophyll environment in the NW Mediterranean Sea

    Science.gov (United States)

    Zervoudaki, S.; Krasakopoulou, E.; Moutsopoulos, T.; Protopapa, M.; Marro, S.; Gazeau, F.

    2017-02-01

    In order to identify how ocean acidification will influence biological interactions and fluxes among planktonic organisms and across trophic levels, a large-scale mesocosm experiment was performed in the oligotrophic Northwestern Mediterranean Sea in the framework of the European MedSeA project. Nine mesocosms were deployed in the Bay of Calvi (Corsica, France) in summer 2012. Six mesocosms were subjected to different levels of CO2 partial pressures (pCO2; 550, 650, 750, 850, 1000 and 1250 μatm) covering the range of atmospheric pCO2 anticipated for the end of this century depending on future emission scenarios, and the last three mesocosms were unaltered (ambient pCO2 of ∼450 μatm). During this 21-day experiment, we monitored copepod egg and naupliar stocks, estimated copepod (Acartia clausi and Centropages typicus) feeding rates and determined the abundance and taxonomic composition of the mesozooplankton community at the start and at the completion of the experiment. This community was clearly dominated by copepods and its final composition slightly varied between mesocosms most likely due to natural and experimental variability that cannot be related to CO2 conditions. The abundances of eggs and nauplii as well as feeding rates of A. clausi and C. typicus on diatoms, dinoflagellates and ciliates showed no significant differences among CO2 levels. The above findings suggest that the experimental set-up especially for the specific trophic conditions and the short duration of the experiment did not provide the information on the effect of acidification that was expected. The acidification might have an effect on planktonic communities and even worsen the problems imposed by food limitation, therefore on this short time scale experiment and under the extreme ologotrophic conditions the signal that dominates was the food limitation.

  14. Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod.

    Science.gov (United States)

    Thor, Peter; Dupont, Sam

    2015-06-01

    Ocean acidification (OA) caused by anthropogenic CO2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short-term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In this study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes. Second generation adults showed a 29% decrease in fecundity at 900 μatm CO2 compared to 400 μatm CO2 . This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO2 . This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO2 . These results highlight the importance of tests for transgenerational effects to avoid overestimation of the effects of OA.

  15. Seasonal phytoplankton blooms in the North Atlantic linked to the overwintering strategies of copepods

    Directory of Open Access Journals (Sweden)

    Kevin D. Friedland

    2016-04-01

    Full Text Available Abstract The North Atlantic Ocean contains diverse patterns of seasonal phytoplankton blooms with distinct internal dynamics. We analyzed blooms using remotely-sensed chlorophyll a concentration data and change point statistics. The first bloom of the year began during spring at low latitudes and later in summer at higher latitudes. In regions where spring blooms occurred at high frequency (i.e., proportion of years that a bloom was detected, there was a negative correlation between bloom timing and duration, indicating that early blooms last longer. In much of the Northeast Atlantic, bloom development extended over multiple seasons resulting in peak chlorophyll concentrations in summer. Spring bloom start day was found to be positively correlated with a spring phenology index and showed both positive and negative correlations to sea surface temperature and the North Atlantic Oscillation in different regions. Based on the characteristics of spring and summer blooms, the North Atlantic can be classified into two regions: a seasonal bloom region, with a well-defined bloom limited to a single season; and a multi-seasonal bloom region, with blooms extending over multiple seasons. These regions differed in the correlation between bloom start and duration with only the seasonal bloom region showing a significant, negative correlation. We tested the hypothesis that the near-surface springtime distribution of copepods that undergo diapause (Calanus finmarchicus, C. helgolandicus, C. glacialis, and C. hyperboreus may contribute to the contrast in bloom development between the two regions. Peak near-surface spring abundance of the late stages of these Calanoid copepods was generally associated with areas having a well-defined seasonal bloom, implying a link between bloom shape and their abundance. We suggest that either grazing is a factor in shaping the seasonal bloom or bloom shape determines whether a habitat is conducive to diapause, while recognizing

  16. Fight and flight in dinoflagellates?

    DEFF Research Database (Denmark)

    Selander, Erik; Fagerberg, Tony; Wohlrab, Sylke;

    2012-01-01

    We monitored the kinetics of grazer-induced responses in the marine dinoflagellate Alexandrium tamarense. Chemical cues from each of three calanoid copepods (Calanus sp., Centropages typicus, and Acartia tonsa) induced increased toxicity and suppressed chain formation in A. tamarense. Both chemical...... divisions, and average biovolume returned to control levels within 1 to 4 d (one to two cell divisions). This suggests that dinoflagellates simultaneously reduce grazer encounter rates and increase chemical defense levels in the presence of copepod grazers. Media replacement experiments showed...

  17. Optimal mate choice patterns in pelagic copepods

    DEFF Research Database (Denmark)

    Heuschele, Jan; Eliassen, Sigrun; Kiørboe, Thomas

    2013-01-01

    The importance of sexual selection for the evolution, dynamics and adaptation of organisms is well known for many species. However, the topic is rarely studied in marine plankton, the basis of the marine food web. Copepods show behaviors that suggest the existence of sexually selected traits......, and recent laboratory experiments identified some selected morphological traits. Here, we use a ‘life history-based’ model of sex roles to determine the optimal choosiness behavior of male and female copepods for important copepod traits. Copepod females are predicted to be choosy at population densities...... typically occurring during the main breeding season, whereas males are not. The main drivers of this pattern are population density and the difference in non-receptive periods between males and females. This suggests that male reproductive traits have evolved mainly due to mate competition. The model can...

  18. Feeding strategies of four dominant copepod species in Prydz Bay, Antarctica: Insights from a combined fatty acid biomarker and stable isotopic approach

    Science.gov (United States)

    Yang, Guang; Li, Chaolun; Guilini, Katja; Peng, Quancai; Wang, Yanqing; Zhang, Ye; Zhang, Yongshan

    2016-08-01

    Using fatty acid biomarkers and stable isotopic signatures, we investigated the feeding strategies and dietary preferences of four dominant copepod species (Calanoides acutus, Calanus propinquus, Metridia gerlachei and Rhincalanus gigas) sampled during the late austral summer in Prydz Bay, Antarctica. Our results show that diatoms, dinoflagellates and ciliates dominated copepod food sources (hypothesized to be phytoplankton and particulate organic matter) in the inner bay regions more than in the oceanic regions of Prydz Bay. Regional differences in the composition and abundance of food sources were also reflected in the fatty acid biomarkers and stable isotopic values. In the inner bay region, the total fatty acid contents of these food sources were nearly twofold higher, including greater contributions from fatty acids of dinoflagellate origin; these samples also had higher δ13C and δ15N values. Fatty acid biomarkers and stable isotopic values in copepod species roughly mirrored the spatial patterns in food sources. As found in the primary producers, the concentrations of dinoflagellate fatty acids and δ13C and δ15N values were higher in copepods from the inner bay regions. Additionally, there were inter-species differences in the fatty acids and stable isotopic values of copepods. C. acutus and C. propinquus did not exhibit significant regional differences in their total fatty acid contents. In contrast, M. gerlachei from the inner bay region had higher fatty acid values. C. acutus and C. propinquus had higher compositions of the long chain fatty acids 20:1n-9, 22:1n-9 and 22:1n-1, while docosahexaenoic acid (DHA) was higher in M. gerlachei. The δ15N values indicate that C. acutus occupies a higher trophic level than the other copepod species. Similarly, higher fatty acid ratios in M. gerlachei, including DHA/EPA(eicosapntemacnioc acid) and 18:1n-9/18:1n-7, indicate that this species feeds more opportunistically and prefers a carnivorous diet. Insights from

  19. Short-term changes in the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn: reflections of a strong wind event

    Science.gov (United States)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-07-01

    To evaluate the effect of atmospheric turbulence on a marine ecosystem, high-frequency samplings (two to four times per day) of a mesozooplankton community and the gut pigment of dominant copepods were performed at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the biomass of chlorophyll a (Chl a) increased, especially for micro-size (> 10 μm) fractions. The zooplankton abundance ranged from 23 610 to 56 809 ind. m-2 and exhibited no clear changes as a result of the SWE. In terms of abundance, calanoid copepods constituted the dominant taxa (mean: 57 %), followed by barnacle larvae (31 %). Within the calanoid copepods, small-sized Pseudocalanus spp. (65 %) and large-sized C. glacialis (30 %) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with the SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient Chl a (Chl a, and a significant increase was observed after the SWE (2.6 vs. 4.5 ng pigment ind.-1). The grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6 % of the biomass of the micro-size phytoplankton. Compared with the metabolic food requirement, C. glacialis feeding on phytoplankton accounted for 12.6 % of their total food requirement. These facts suggest that C. glacialis could not maintain their population by feeding solely on phytoplankton and that other food sources (i.e., microzooplankton) must be important in autumn. As observed by the increase in gut pigment, the temporal phytoplankton bloom, which is enhanced by the atmospheric turbulence (SWE) in autumn, may have a positive effect on copepod nutrition.

  20. Observing copepods through a genomic lens

    Directory of Open Access Journals (Sweden)

    Johnson Stewart C

    2011-09-01

    Full Text Available Abstract Background Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to

  1. Copepods and fishes in the Brazilian Amazon

    Science.gov (United States)

    Thatcher, Vernon E.

    1998-06-01

    The Amazon basin comprises the largest river ecosystem in the world (7 million km 2) with annual high and low water peaks and a constant temperature near 29°C. Some 2000 fish species and 40 species of free-living copepods are known to occur in Amazonia. The free-living forms serve as food for most larval fishes and some adults, but they also transmit several parasites including representatives of the nematode family Camallanidae. About three dozen species of parasitic copepods have been described from the Brazilian Amazon. Females of Amazonian parasitic copepods are found on skin, gill filaments, gill rakers or within the nasal fossae. Parasitic copepods are found on fishes that are from a few millimeters long up to those over 2 m in length and they are usually quite host specific. All have body pigmentation in different patterns and colors (frequently blues, such as cerulean, cobalt, spectrum, smalt or campanula). It is suggested that the coloration serves to attract specific host fish. Copepods have evolved adaptations for attachment and feeding, especially in the second antennae and endopods. Examples of progenesis, phoresis and commensalism are shown. Some species produce pathology such as a tourniquet effect, hyperplasia, blood loss and anemia, and can kill fishes by limiting their respiration.

  2. Prey detection in a cruising copepod

    DEFF Research Database (Denmark)

    Kjellerup, Sanne; Kiørboe, Thomas

    2012-01-01

    Small cruising zooplankton depend on remote prey detection and active prey capture for efficient feeding. Direct, passive interception of prey is inherently very inefficient at low Reynolds numbers because the viscous boundary layer surrounding the approaching predator will push away potential prey....... Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile...

  3. A plea for the use of copepods in freshwater ecotoxicology

    DEFF Research Database (Denmark)

    Kulkarni, Devdutt; Gergs, André; Hommen, Udo

    2013-01-01

    . However, very little is known about the ecotoxicology of freshwater copepods. To enable a more realistic risk higher tier environmental risk assessment, we recommend considering freshwater copepods as part of the hazard assessment process. This could include the establishment of laboratory experiments...... consequences concerning the vulnerability of such species to exposure with contaminants. We aimed to highlight the importance of copepods in ecology and to underline the need to include freshwater copepods in ecotoxicology. We carried out a literature search on copepods and Daphnia in ecology and ecotoxicology...

  4. A plea for the use of copepods in freshwater ecotoxicology.

    Science.gov (United States)

    Kulkarni, Devdutt; Gergs, André; Hommen, Udo; Ratte, Hans Toni; Preuss, Thomas G

    2013-01-01

    Standard species used in ecological risk assessment are chosen based on their sensitivity to various toxicants and the ease of rearing them for laboratory experiments. However, this mostly overlooks the fact that species in the field that may employ variable life-history strategies, which may have consequences concerning the vulnerability of such species to exposure with contaminants. We aimed to highlight the importance of copepods in ecology and to underline the need to include freshwater copepods in ecotoxicology. We carried out a literature search on copepods and Daphnia in ecology and ecotoxicology to compare the recognition given to these two taxa in these respective fields. We also conducted a detailed analysis of the literature on copepods and their current role in ecotoxicology to characterize the scale and depth of the studies and the ecotoxicological information therein. The literature on the ecology of copepods outweighed that in ecotoxicology when compared with daphnids. Copepods, like other zooplankton, were found to be sensitive to toxicants and important organisms in aquatic ecosystems. The few studies that were conducted on the ecotoxicology of copepods mainly focused on marine copepods. However, very little is known about the ecotoxicology of freshwater copepods. To enable a more realistic risk higher tier environmental risk assessment, we recommend considering freshwater copepods as part of the hazard assessment process. This could include the establishment of laboratory experiments to analyse the effects of toxicants on copepods and the development of individual-based models to extrapolate effects across species and scenarios.

  5. A trait database for marine copepods

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Payne, Mark; Kiørboe, Thomas

    2017-01-01

    The trait-based approach is gaining increasing popularity in marine plankton ecology but the field urgently needs more and easier accessible trait data to advance.We compiled trait information on marine pelagic copepods, a major group of zooplankton, from the published literature and from experts...

  6. Colloquium on diatom-copepod interactions

    DEFF Research Database (Denmark)

    Paffenhofer, G.A.; Ianora, A.; Miralto, A.;

    2005-01-01

    From 3 to 6 November 2002, a colloquium was convened at the Benthos Laboratory of the Stazione Zoologica Anton Dohrn on Ischia, Italy, with the goal of evaluating the present status of the effects of diatoms on their main consumers, planktonic copepods, and to develop future research strategies...

  7. Distribution of dominant calanoid copepod species in the Greenland Sea during late fall; 06 November 1988 to 12 December 1988 (NODC Accession 0000917)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Between 6 November and 12 December 1988, vertical distributions of Calanus finmarchicus, C. hyperboreus, C. glacialis adn Metridia long were studied at three...

  8. Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia

    KAUST Repository

    Mojib, Nazia

    2014-06-01

    The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid–protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin–protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton.

  9. Effects of anti-androgens cyproterone acetate, linuron, vinclozolin, and p,p'-DDE on the reproductive organs of the copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Watermann, Burkard T.; Albanis, Triantafyllos A.; Galassi, Silvana

    2016-01-01

    stimulated, whereas others displayed a disturbed spermatogenesis and a deformed spermatophore wall. In VIN exposed female A. tonsa, no effects were observed. Male A. tonsa exposed to p,p'-DDE displayed an impairment of spermatogenesis in all stages with increased degrees of apoptosis. In p...

  10. Annual variation of copepod community in the Yangshan Port%洋山港浮游桡足类群落的周年变化特征

    Institute of Scientific and Technical Information of China (English)

    王琼; 陈辰; 吴惠仙; 袁林; 边佳胤; 庄骅; 薛俊增

    2013-01-01

    To understand the annual variation of the copepod community structure, abundance, dominant species and diversity in the Yangshan Port, samples were collected monthly from March 2009 to February 2010. The results showed that the dominant species were Limnoithona tetraspina, Acartia pacifica, Labidocera euchaeta, Paraca-lanus aculeatus, Acartia bifilosa, Microsetella norvegica, Paracalanus gracilis and Paracalanus parvus. The sea-sonal variation in the mean abundance was remarkable(F=2.11, P夏(18.60个/L±14.81个/L)>冬(10.98个/L±3.65个/L)>秋(10.57个/L±4.45个/L);生物量则为夏(12359.1 mg/L±18438.1 mg/L)>秋(7796.6 mg/L±1348.6 mg/L)>冬(2944.8 mg/L±1680.9 mg/L)>春(1401.0 mg/L±1057.3 mg/L).桡足类丰度的周年变化呈现双峰型特征,生物量变化呈现单峰型特征.多变量分析显示,优势种的数量变化对洋山港桡足类群落丰度和生物量的季节变化起主要作用.小洋山码头受人类干扰严重,桡足类丰度和多样性与大洋山码头已出现差异,春、冬季小洋山码头的多样性指数(H′)高于大洋山码头,除秋季外,小洋山码头的均匀度指数(J)都高于大洋山码头.

  11. Mortality of marine planktonic copepods : global rates and patterns

    DEFF Research Database (Denmark)

    Hirst, A.G.; Kiørboe, Thomas

    2002-01-01

    in broadcast spawners, while mortality in sac spawners is invariant with body size. Although the magnitude of copepod mortality does lie close to the overall general pattern for pelagic animals, copepod mortality scaling is much weaker, implying that small copepods are avoiding some mortality agent....../s that other pelagic animals of a similar size do not, We compile direct in situ estimates of copepod mortality and compare these with our indirect predictions; we find the predictions generally match the field measurements well with respect to average rates and patterns. Finally, by comparing in situ adult...

  12. COPEPOD: The Coastal & Oceanic Plankton Ecology, Production, & Observation Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal & Oceanic Plankton Ecology, Production, & Observation Database (COPEPOD) provides NMFS scientists with quality-controlled, globally distributed...

  13. Spatial heterogeneity of zooplankton abundance and diversity in the Saudi coastal waters of the Southern Red Sea

    Science.gov (United States)

    Al-Aidaroos, Ali; El-Sherbiny, Mohsen; Mantha, Gopikrishna

    2013-04-01

    The horizontal distribution, abundance and diversity of zooplankton has been studied at 50 stations along the Saudi coastal waters of the southern Red Sea (27 stations around Farasan archipelago, 9 around Al-Qunfodah and 14 around Al-Lith) during March-April 2011 using a plankton net of 150 µm. The zooplankton standing crop fluctuated between 1058 and 25787 individuals/m3 with an average of 5231 individuals/m3. Zooplankton was dominated by holoplanktonic forms that representing 80.26 % of total zooplankton, while meroplanktonic constituting 19.74% and dominated by mollusc larvae. Copepods appeared to be the predominant component, formed an average of 69.69 % of the total zooplankton count followed by chaetognaths and urochordates (4.5 and 4.1% of total zooplankton respectively). A total of 100 copepods species in addition to several species of other planktonic groups (cladocerans, chaetognaths, urochordates) were recorded in the study area. The copepod diversity decreased northward (94, 69 and 62 species at Farasan, Al-Qunfodah and Al-Lith respectively). In general, adult cyclopoid copepods dominated the zooplankton community in term of abundance and species number (19.55 %, 65 species) with dominance of Oncaea media, Oithona similis and Farranula carinata followed by adult calanoid copepods (19.38%, 35 species) with dominance of Paracalanus aculeatus, Clausocalanus minor, Acartia (Acanthacartia) fossae and Centropages orsinii. Harapacticoids densities were low in abundance, represented only by 5 species and dominated mainly by Euterpina acutifronis. Some copepod species decreased northward: Acartia amboinensis, Canthocalanus pauper, Labidocera acuta, Corycaeus flaccus, C. typicus, C. agilis, C. catus, C. giesbrechti, C. latus, C. furcifer and Euterpina acutifronis, while others increased northward (Acartia fossae, Undinula vulgaris and Centropages orsinii). Among copepod orders, Monstrilloida and Siphonostomatoida were observed only in southern area (Farasan

  14. Reduction of hydrocarbon contamination on viability of Acartia pacifica benthic resting eggs

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiaodong; WANG Guizhong; LIN Qiongwu

    2008-01-01

    The potential effect of hydrocarbon contamination on the hatching success of benthic resting eggs of Acartia pacifica in Xiamen Bay was investigated experimentally.The number of nauplii emerging from the sediment samples decreased with increasing Fuel Oil #0 concentration.The estimated rate of mortality increased markedly with the increase of Fuel Oil #0 concentration.Successive fuel Oil #0 concentrations from 50 mg/kg to 5000 mg/kg reduced the number of hatched nauplii by 3.8%-100%.The mortality of A.pacifica resting eggs due to Fuel Oil #0 contamination did not significantly increase as time progressed at each concentration level.The LC50 values of resting eggs,changing from 237.12 to 279.59 mg/kg,remained at an almost stable level in two months.The number of A.pacifica nauplii that hatched from the sediment at 10℃ was higher than those from the sediment at 30℃,which indicates that the toxicity of Fuel Oil #0 on A.pacifica resting eggs increases with increasing temperature.

  15. Propagation of planktonic copepods: production and mortality of eggs

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Møhlenberg, Flemming; Tiselius, Peter

    1988-01-01

    Data on fecundity and egg mortality of neritic copepods were collected in various seasons, areas and under various hydrographical conditions. On a seasonal basis variations in fecundity (F) were related to temperature rather than to the abundance of phytoplankton (P). However, a strong correlation....... The implications for phenology and distribution of copepods are discussed....

  16. Copepods use chemical trails to find sinking marine snow aggregates

    DEFF Research Database (Denmark)

    Lombard, Fabien; Koski, Marja; Kiørboe, Thomas

    2013-01-01

    Copepods are major consumers of sinking marine particles and hence reduce the efficiency of the biological carbon pump. Their high abundance on marine snow suggests that they can detect sinking particles remotely. By means of laboratory observations, we show that the copepod Temora longicornis ca...

  17. Propulsion efficiency and imposed flow fields of a copepod jump

    DEFF Research Database (Denmark)

    Jiang, H.; Kiørboe, Thomas

    2011-01-01

    velocity vectors pointing towards the copepod; such a flow field may inform the predator of the whereabouts of the escaping copepod prey. High Froude propulsion efficiency (0.94–0.98) was obtained for individual power stroke durations of all simulated jumps. This is unusual for small aquatic organisms...

  18. Does copepods influence dusky grouper (Epinephelus marginatus early development?

    Directory of Open Access Journals (Sweden)

    Monica Mateus

    2014-06-01

    Full Text Available Good knowledge on the development of early life stages is essential for successful conservation programs of threatened fish species. Diet and rearing system affects early life survival and juvenile quality. Copepods are the natural food of fish larvae in the wild possessing high nutritional value, when compared with live feeds used in aquaculture (rotifers and artemia, and a wide range of size classes. Rearing systems with low water column disturbance and low larval densities enhanced the survival of fragile fish larvae. The aim of this work is to evaluate the effect of the introduction of copepods in the diet of early dusky grouper larvae reared in controlled mesocosm systems using larval development and juvenile quality as indicators. Two feeding protocols were tested, one composed only by rotifers (Brachionus plicatilis, brine shrimp (Artemia spp. and dry feed and the other supplemented with copepods (Paracartia grani from mouth opening (2 day after hatching - DAH to 8 DAH. Feeding behavior, growth, survival, skeletal malformations and digestive enzymes activity was assessed at different developmental stages. The addition of copepods to the early larvae diet of dusky grouper resulted in faster development and higher survival rates. Larvae fed with copepods improved their development. At 20 DAH all larvae reared at the mesocosm with copedods were already at the stage of post-flexion while in the system without copepods this stage was attained later. At 25 DAH only 64% of the larvae were in post flexion in the mesoscosm without copepods. At 30 DAH larvae supplemented with copepods attained an acidic digestion (high specific activity of pepsin earlier than at the system without copepods. In this last system alkaline digestion (trypsin specific activity, characteristic of early larval stages, was significantly higher reinforcing the faster development of larvae fed with copepods. In both systems the incidence of skeletal malformations was low.

  19. Population dynamics of Acartia pacifica (Copepoda:Calanoida):the importance of benthic-pelagic coupling

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiaodong; WANG Guizhong; LI Shaojing

    2006-01-01

    The seasonal occurrence of Acartia pacifica (Copepoda: Calanoida) and their resting eggs in the sediment of Xiamen Bay were documented between October 2002 and September 2003. The number of viable eggs in the sediment increased from January to May with the increase in the number of planktonic females. When the population of A. Pacifica disappeared from the water column, the number of eggs in the sediment began to decrease and reached a low value due to lack of input. The peak of nauplii abundance occurred when the hatching potential of eggs from the sediment was high under the natural environment from February to June. The hatching of resting eggs of A. Pacifica was essentially temperature-dependent after suspension, while photoperiod regimes had no significant effect on the hatching. The mean density of subitaneous eggs was 1.122 0 g/cm3 with a standard deviation (SD) of 0.000 2 g/cm3. The mean density of diapause eggs was 1.151 2 g/cm3 with a SD of 0.000 1 g/cm3. The sinking rates of subitaneous eggs ranged from 19.55 to 26.17 m/d, while those of diapause eggs ranged from 30.29 to 31.28 m/d. The comparison of the egg deposition time and egg hatching time suggested that in most cases virtually all subitaneous eggs of A. Pacifica would settle to the bottom before their hatching even though the eggs have high potential to hatch. The evidence was provided that the seasonal dynamics of A. Pacifica is accompanied by benthic-pelagic coupling.

  20. A trait database for marine copepods

    Science.gov (United States)

    Brun, Philipp; Payne, Mark R.; Kiørboe, Thomas

    2017-02-01

    The trait-based approach is gaining increasing popularity in marine plankton ecology but the field urgently needs more and easier accessible trait data to advance. We compiled trait information on marine pelagic copepods, a major group of zooplankton, from the published literature and from experts and organized the data into a structured database. We collected 9306 records for 14 functional traits. Particular attention was given to body size, feeding mode, egg size, spawning strategy, respiration rate, and myelination (presence of nerve sheathing). Most records were reported at the species level, but some phylogenetically conserved traits, such as myelination, were reported at higher taxonomic levels, allowing the entire diversity of around 10 800 recognized marine copepod species to be covered with a few records. Aside from myelination, data coverage was highest for spawning strategy and body size, while information was more limited for quantitative traits related to reproduction and physiology. The database may be used to investigate relationships between traits, to produce trait biogeographies, or to inform and validate trait-based marine ecosystem models. The data can be downloaded from PANGAEA, http://dx.doi.org/10.1594/PANGAEA.862968" target="_blank">doi:10.1594/PANGAEA.862968.

  1. DISTRIBUTION AND POPULATION DYNAMICS OF PARACALANUS PARVUS, PARACALANUS CRASSIROSTRIS, AND ACARTIA BIFILOSA (COPEPODA, CALANOIDA) IN THE BOHAI SEA

    Institute of Scientific and Technical Information of China (English)

    王荣; 张鸿雁; 王克; 左涛

    2002-01-01

    Paracalanus parvus, Paracalanus crassirostris, and Acartia bifilosa ar e dominant and widely distributed in the Bohai Sea, and comprise an important part of zooplankton in terms of biomass as well as production rate. In order to understa nd their seasonal distribution and population dynamics, their stage-specific abund ance in different months of the year were analyzed based on the never analyzed yet sa mples collected in 1959. The three species showed clear and remarkable seasonal variat ion in abundance, which maximized in spring and summer, when they formed high biomas s patches or concentrations in the nearshore area. For Paracalanus parvus, two peaks were observed in the annual circle, one in June and the other in September. For Paracalanus crassirostris, one peak occurred in summer and a small one in De cember. The seasonal pattern of Acartia bifilosa was different in different regions. In Bohai Bay it had a two-peak pattern, with the first large peak occurring in May and t he second one in October. In Laizhou Bay, a winter peak in December and January cou ld be observed besides the spring one. The number of generations during the reprodu ctive season for the three species was estimated based on the annual cycle in abundanc e and ambient temperature.

  2. Production and use of copepods in marine fish larviculture

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Norsker, N.H.

    1997-01-01

    substratum. Two such systems were compared in terms of area productivity and the use of ammonia excretion as a means for controlling feeding of the copepods was investigated. Finally, the potential benefits of the use of copepods as live food for marine fish larvae are discussed. (C) 1997 Elsevier Science B.V...... swimming behaviour in terms of vertical distribution in a typical fish larval tank and the use of T. holothuriae nauplii as live food for first-feeding turbot larvae were investigated. It was possible to cultivate harpacticoid copepods in shallow trays or in continuous bioreactors with large area...

  3. Does copepod size determine food consumption of particulate feeding fish?

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Koski, Marja; Rindorf, Anna

    2014-01-01

    on adult particulate feeding fish is unknown. In the present study, we investigated the hypothesis that the availability of the large copepods determines food consumption and growth conditions of lesser sandeel (Ammodytes marinus) in the North Sea. Analysis of stomach content suggested that food...... consumption is higher for fish feeding on large copepods, and additional calculations revealed how handling time limitation may provide part of the explanation for this relationship. Comparing stomach data and zooplankton samples indicated that lesser sandeel actively target large copepods when...

  4. The fluid dynamics of swimming by jumping in copepods

    DEFF Research Database (Denmark)

    Jiang, Houshuo; Kiørboe, Thomas

    2011-01-01

    Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic...... limited and temporally ephemeral owing to jump-impulsiveness and viscous decay. In contrast, continuous steady swimming generates two well-extended long-lasting momentum jets both in front of and behind the swimmer, as suggested by the well-known steady stresslet model. Based on the observed jump-swimming...... kinematics of a small copepod Oithona davisae, we further showed that jump-swimming produces a hydrodynamic disturbance with much smaller spatial extension and shorter temporal duration than that produced by a same-size copepod cruising steadily at the same average translating velocity. Hence, small copepods...

  5. Stage-dependent and sex-dependent sensitivity to water-soluble fractions of fresh and weathered oil in the marine copepod Calanus finmarchicus.

    Science.gov (United States)

    Jager, Tjalling; Altin, Dag; Miljeteig, Cecilie; Hansen, Bjørn Henrik

    2016-03-01

    Acute toxicity differs between species but also varies within a species. Important intraspecific factors are the exposure duration and properties of the animal such as life stage, sex, and physiological status. In the present study, the acute toxicity of water-soluble fractions (WSFs) from fresh and artificially weathered oil was followed over time in different life stages of the calanoid copepod Calanus finmarchicus, including adult males and females. The life stages differ in size but also in lipid content and physiology. To meaningfully compare the sensitivity of the different stages, the authors fitted a toxicokinetic-toxicodynamic (TKTD) model from the framework of the General Unified Threshold Model of Survival (GUTS) to the mortality patterns over time. The oil WSFs could not be treated as single compounds: the rapid effect at high doses could not be reconciled with the slow effect at low doses. Treating the oil as a mixture of 2 component blocks could, however, capture these patterns satisfactorily. Even though the early life stages of animals are generally considered to be the most vulnerable, the adult males of C. finmarchicus turned out to be most sensitive, followed by the early copepodites. Naupliar larvae were equally susceptible to oil toxicity as late copepodites and adult females. The relationship between the GUTS model parameters and the physiological traits for the different life stages remains, however, unclear.

  6. Redescription of the poorly known planktonic copepod Pontellopsis lubbockii (Giesbrecht, 1889 (Pontellidae from the Eastern Tropical Pacific with a key to species

    Directory of Open Access Journals (Sweden)

    Eduardo Suarez-Morales

    2012-10-01

    Full Text Available During a survey of the epipelagic zooplankton carried out off the coast of the Mexican states of Jalisco and Colima, in the Eastern Tropical Pacific, female and male specimens of the poorly known calanoid copepod Pontellopsis lubbockii (Giesbrecht, 1889 were collected. Because previous descriptions and illustrations are largely incomplete and have caused some taxonomical confusion, this species is fully redescribed from specimens from the Mexican Pacific. The species has some characters that have been overlooked, but those related to the female genital double-somite are the most striking, it has two conical dorsal protuberances and a long ventral spiniform process unique of this species. The mouthparts of this species have not been hitherto described and figured, the flexible terminal setae of legs 3 and 4 is noteworthy. The male general morphology agrees in general with previous data, but new details of the leg 5 and geniculate antennule are added. Its mouthparts, with strong, serrate setae on the maxillae and maxillules, and a strong mandibular edge, suggest that this is a predator form. A dichotomous key for the identification of males and females of the species of Pontellopsis known from the Eastern Tropical Pacific is included.

  7. Redescription of the poorly known planktonic copepod Pontellopsis lubbockii (Giesbrecht, 1889) (Pontellidae) from the Eastern Tropical Pacific with a key to species.

    Science.gov (United States)

    Suárez-Morales, Eduardo; Kozak, Eva

    2012-01-01

    During a survey of the epipelagic zooplankton carried out off the coast of the Mexican states of Jalisco and Colima, in the Eastern Tropical Pacific, female and male specimens of the poorly known calanoid copepod Pontellopsis lubbockii (Giesbrecht, 1889) were collected. Because previous descriptions and illustrations are largely incomplete and have caused some taxonomical confusion, this species is fully redescribed from specimens from the Mexican Pacific. The species has some characters that have been overlooked, but those related to the female genital double-somite are the most striking, it has two conical dorsal protuberances and a long ventral spiniform process unique of this species. The mouthparts of this species have not been hitherto described and figured, the flexible terminal setae of legs 3 and 4 is noteworthy. The male general morphology agrees in general with previous data, but new details of the leg 5 and geniculate antennule are added. Its mouthparts, with strong, serrate setae on the maxillae and maxillules, and a strong mandibular edge, suggest that this is a predator form. A dichotomous key for the identification of males and females of the species of Pontellopsis known from the Eastern Tropical Pacific is included.

  8. Hydrodynamics and energetics of jumping copepod nauplii and copepodids

    DEFF Research Database (Denmark)

    Wadhwa, Navish; Andersen, Anders Peter; Kiørboe, Thomas

    2014-01-01

    , we measured the swimming kinematics and fluid flow around jumping Acartia tonsa at different stages of its life cycle, using particle image velocimetry and particle tracking velocimetry. We found that the flow structures around nauplii and copepodids are topologically different, with one and two...... vortex rings, respectively. Our measurements suggest that copepodids cover a larger distance compared to their body size in each jump and are also hydrodynamically quieter, as the flow disturbance they create attenuates faster with distance. Also, copepodids are energetically more efficient than nauplii...

  9. Status and recommendations on marine copepod cultivation for use as live feed

    DEFF Research Database (Denmark)

    Drillet, Guillaume; Frouël, Stéphane; Sichlau, Mie Hylstofte;

    2011-01-01

    Copepods are important crustaceans studied because of their key role in ecology, trophic biology, fisheries management, in modeling the flow of energy and matter, ecotoxicology, aquaculture and aquarium trade. This paper discusses various aspects of the state of knowledge of copepod culture at la...... of probiotics for improving the fitness of copepod cultures; and 6) encourage copepod producers/retailers to use/develop an efficient sales and marketing strategy....

  10. History repeats itself: genomic divergence in copepods.

    Science.gov (United States)

    Renaut, Sébastien; Dion-Côté, Anne-Marie

    2016-04-01

    Press stop, erase everything from now till some arbitrary time in the past and start recording life as it evolves once again. Would you see the same tape of life playing itself over and over, or would a different story unfold every time? The late Steven Jay Gould called this experiment replaying the tape of life and argued that any replay of the tape would lead evolution down a pathway radically different from the road actually taken (Gould 1989). This thought experiment has puzzled evolutionary biologists for a long time: how repeatable are evolutionary events? And if history does indeed repeat itself, what are the factors that may help us predict the path taken? A powerful means to address these questions at a small evolutionary scale is to study closely related populations that have evolved independently, under similar environmental conditions. This is precisely what Pereira et al. (2016) set out to do using marine copepods Tigriopus californicus, and present their results in this issue of Molecular Ecology. They show that evolution can be repeatable and even partly predictable, at least at the molecular level. As expected from theory, patterns of divergence were shaped by natural selection. At the same time, strong genetic drift due to small population sizes also constrained evolution down a similar evolutionary road, and probably contributed to repeatable patterns of genomic divergence.

  11. Copepod assemblages in a highly complex hydrographic region

    Science.gov (United States)

    Berasategui, A. D.; Menu Marque, S.; Gómez-Erache, M.; Ramírez, F. C.; Mianzan, H. W.; Acha, E. M.

    2006-02-01

    Community structure and diversity patterns of planktonic copepods were investigated for the Southwestern Atlantic Ocean between 34 and 41°S. Our objectives were (1) to define copepod assemblages, (2) to accurately identify their association to different water masses/hydrodynamic regimes, (3) to characterize the assemblages in terms of their community structure, and (4) to test if frontal boundaries between water masses separate copepod assemblages. Biogeographic patterns were investigated using multivariate analysis (cluster and ANOSIM analyses). Biodiversity patterns were examined using different univariate indexes (point species richness and taxonomic distinctness). Five regions of similar copepod assemblages were defined for our study area each one corresponding to different environments (freshwater, estuarine, continental shelf, Malvinas and Brazil current assemblages). These assemblages have major community structure differences. In spite of the complex oceanographic scenario of our study area, that can lead us to expect a pattern of copepod communities with diffuse boundaries, we found a strong spatial correspondence between these limits and the presence of permanent frontal structures.

  12. Strategies for success: Copepods in a seasonal world

    DEFF Research Database (Denmark)

    Sainmont, Julie

    their predator (chapter 3). In addition to controlling trophic transfer in marine ecosystems, DVM also plays a potential role biogeochemistry of the worlds oceans. A simple modeling method taking behavior into account in large models is therefore needed, as ocean system model are already computationally......Amongst the zooplankton community, copepods display complex and diverse life history strategies, which could explain their wide success in the world ocean. Specically, in temperate and high latitude ecosystems, copepods are subject to \\boom and bust" conditions where annual cycles are punctuated...... by a short, productive spring blooms, but with relatively little food and harsh conditions for the rest of the year. Due to their world-wide dominance in biomass, and their importance in the food webs, copepods are fairly well studied. However, the success of their complex life-history strategies remain open...

  13. Copepod guts as biogeochemical hotspots in the sea

    DEFF Research Database (Denmark)

    Tang, Kam W.; Glud, Ronnie N.; Glud, Anni;

    2011-01-01

    , with a steep gradient from the anal opening to the metasome region. The central metasome region was completely anoxic. Food remains in the gut led to a lower oxygen level, and a diatom diet induced a stronger oxygen gradient than a cryptophyte diet. The acidic and suboxic–anoxic environments of the copepod gut...

  14. The copepod Calanus spp. (Calanidae) is repelled by polarized light

    Science.gov (United States)

    Lerner, Amit; Browman, Howard I.

    2016-10-01

    Both attraction and repulsion from linearly polarized light have been observed in zooplankton. A dichotomous choice experiment, consisting of plankton light traps deployed in natural waters at a depth of 30 m that projected either polarized or unpolarized light of the same intensity, was used to test the hypothesis that the North Atlantic copepod, Calanus spp., is linearly polarotactic. In addition, the transparency of these copepods, as they might be seen by polarization insensitive vs. sensitive visual systems, was measured. Calanus spp. exhibited negative polarotaxis with a preference ratio of 1.9:1. Their transparency decreased from 80% to 20% to 30% in the unpolarized, partially polarized, and electric (e-) vector orientation domains respectively - that is, these copepods would appear opaque and conspicuous to a polarization-sensitive viewer looking at them under conditions rich in polarized light. Since the only difference between the two plankton traps was the polarization cue, we conclude that Calanus spp. are polarization sensitive and exhibit negative polarotaxis at low light intensities (albeit well within the sensitivity range reported for copepods). We hypothesize that Calanus spp. can use polarization vision to reduce their risk of predation by polarization-sensitive predators and suggest that this be tested in future experiments.

  15. Macroevolutionary patterns of sexual size dimorphism in copepods

    DEFF Research Database (Denmark)

    Hirst, Andrew G.; Kiørboe, Thomas

    2014-01-01

    , and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes....

  16. Vibrio elicits targeted transcriptional responses from copepod hosts.

    Science.gov (United States)

    Almada, Amalia A; Tarrant, Ann M

    2016-06-01

    Copepods are abundant crustaceans that harbor diverse bacterial communities, yet the nature of their interactions with microbiota are poorly understood. Here, we report that Vibrio elicits targeted transcriptional responses in the estuarine copepod Eurytemora affinis We pre-treated E. affinis with an antibiotic cocktail and exposed them to either a zooplankton specialist (Vibrio sp. F10 9ZB36) or a free-living species (Vibrio ordalii 12B09) for 24 h. We then identified via RNA-Seq a total of 78 genes that were differentially expressed following Vibrio exposure, including homologs of C-type lectins, chitin-binding proteins and saposins. The response differed between the two Vibrio treatments, with the greatest changes elicited upon inoculation with V. sp. F10 We suggest that these differentially regulated genes play important roles in cuticle integrity, the innate immune response, and general stress response, and that their expression may enable E. affinis to recognize and regulate symbiotic vibrios. We further report that V. sp. F10 culturability is specifically altered upon colonization of E. affinis These findings suggest that rather than acting as passive environmental vectors, copepods discriminately interact with vibrios, which may ultimately impact the abundance and activity of copepod-associated bacteria.

  17. Prey perception in feeding-current feeding copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Goncalves, Rodrigo J.; Florian Couespel, Damien

    2016-01-01

    We reply to the comments of Paffenhöfer and Jiang () who argues that remote chemical prey perception is necessary for feeding-current feeding copepods to fulfill their nutritional requirements in a dilute ocean, that remote chemical prey detection may only be observed at very low prey concentrati...

  18. Cyclopoid copepods (Lichomolgidae) from octocorals at Eniwetok Atoll

    NARCIS (Netherlands)

    Humes, Arthur G.

    1973-01-01

    This report of lichomolgid copepods found for the first time associated with octocorals in the Pacific Ocean includes six species, two of them new. Paramolgus eniwetokensis n. sp. and Paramolgus ostentus n. sp. are associated with Lobophytum pauciflorum (Ehrenberg). New host records include Acanthom

  19. Motility of copepod nauplii and implications for food encounter

    DEFF Research Database (Denmark)

    Titelman, Josefin; Kiørboe, Thomas

    2003-01-01

    of tracks, speeds, durations and frequencies of events as well as time budgets. Motility mode often changes drastically during naupliar ontogeny. Crudely, nauplii can be divided into those moving with a jump-sink type of motility of various frequencies (1 min(-1) to 3 s(-1)) and those swimming...... with a smoother glide of varying continuity. We apply observed time budgets and behavior-specific speeds in simple models to examine mechanisms of food encounter. The motility of all nauplii may account for clearance rates reported in the literature, but through different mechanisms. Smoothly swimming nauphi...... cyclopoids is sufficient to prevent prey diffusion from reaching steady state rates, which are too low to account for observed clearance rates reported in the literature. Frequent jumpers (e.g. Acartia tonsa) jump at a frequency close to the optimum required to maximize the use of prey motility and to avoid...

  20. Diversity of

    Directory of Open Access Journals (Sweden)

    Mohamed M. Abou Zaid

    2014-01-01

    Full Text Available Seasonal abundance, biomass, and taxonomic composition of copepods in El-Mex Bay (Southeastern Mediterranean region were studied from autumn 2011 to 2012. Most species within the copepod communities displayed a clear pattern of succession throughout the investigation period. Generally copepods were the predominant group. They contributed numerically 57% of the total zooplankton counts with an average of 5083 organisms/m3 and a total number of 203,333 individuals. The bay harbored 50 species belonging to 28 genera within 19 families and 4 orders under one class. Calanoids were represented by 24 species which formed 31.6% of total copepods predominantly Acartia clausi, Calocalanus pavo, Clausocalanus furcatus, Eucalanus crassus, Nannocalanus minor, Paracalanus parvus, Eucalanus subcrassus, and Temora longicornis. Cyclopoids comprised 13 species of which Acanthocyclops americanus, Halicyclops magniceps, Oithona attenuata, and Oithona nana were the most abundant adult copepods. Eleven Harpacticoid species were also recorded with Euterpina acutifrons, Microsetella norvegica, Onychocamptus mohammed being the most prevalent. It was found however, that two Poecilostomatoida species were rarely encountered in the plankton Oncaea minuta and Corycaeus typicus. Copepod larvae and copepodite stages formed the main bulk of copepod Fauna as noticed in the El-Mex Bay during the investigation period. Their percentage was 36.7% of the total count and their total numbers were 74,629 individuals with an average of 1866 organisms/m3. The persistent relationships between total copepod counts, copepod orders, and physico-chemical variables suggested that physical factors operate on the copepod communities, either directly to limit maximum distribution along the bay, or indirectly on abundance.

  1. Feeding ecology of the copepod Lucicutia aff. L. grandis near the lower interface of the Arabian Sea oxygen minimum zone

    Science.gov (United States)

    Gowing, Marcia M.; Wishner, Karen F.

    Feeding ecology of the calanoid copepod Lucicutia aff. L. grandis collected in the Arabian Sea at one station during the Spring Intermonsoon and during the Southwest Monsoon of 1995 was studied with transmission electron microscopy of gut-contents. Highest abundances of these animals occurred from ˜400 to 1100 m, near the lower interface of the oxygen minimum zone and at the inflection point where oxygen starts to increase. We expected that their gut-contents would include particles and cells that had sunk relatively undegraded from surface waters as well as those from within the oxygen minimum zone, and that gut-contents would differ between the Spring Intermonsoon and the more productive SW Monsoon. Overall, in both seasons Lucicutia aff. L. grandis was omnivorous, and consumed a variety of detrital particles, prokaryotic and eukaryotic autotrophs, gram-negative bacteria including metal-precipitating bacteria, aggregates of probable gram-positive bacteria, microheterotrophs, virus-like particles and large virus-like particles, as well as cuticle and cnidarian tissue. Few significant differences in types of food consumed were seen among life stages within or among various depth zones. Amorphous, unidentifiable material was significantly more abundant in guts during the Spring Intermonsoon than during the late SW Monsoon, and recognizable cells made up a significantly higher portion of gut-contents during the late SW Monsoon. This is consistent with the Intermonsoon as a time when organic material is considerably re-worked by the surface water microbial loop before leaving the euphotic zone. In both seasons Lucicutia aff. L. grandis had consumed what appeared to be aggregates of probable gram-positive bacteria, similar to those we had previously found in gut-contents of several species of zooplankton from the oxygen minimum zone in the eastern tropical Pacific. By intercepting sinking material, populations of Lucicutia aff. L. grandis act as a filter for carbon

  2. Effects of elevated carbon dioxide (CO2) concentrations on early developmental stages of the marine copepod Calanus finmarchicus Gunnerus (Copepoda: Calanoidae).

    Science.gov (United States)

    Pedersen, Sindre Andre; Våge, Vegard Thorset; Olsen, Anders Johny; Hammer, Karen Marie; Altin, Dag

    2014-01-01

    Ocean acidification poses an ongoing threat to marine organisms, and early life stages are believed to be particularly sensitive. The boreal calanoid copepod Calanus finmarchicus seasonally dominates the standing stock of zooplankton in the northern North Sea and North Atlantic, and due to its size and abundance is considered an ecological key species linking energy from primary producers to higher trophic levels. To examine whether the early stages of C. finmarchicus are particularly vulnerable to elevated levels of CO2, eggs and nauplii were subjected to different levels of CO2-acidified seawater for 1 wk. The first experiment, with eggs as the starting point, revealed no marked effect on hatching success, but a significant reduction in nauplii survival during incubation at 8800 ppm CO2. In addition, a significant decrease in ontogenetic development rate during incubation at 8800 ppm CO2 was observed in this experiment. In the second experiment, where third-stage nauplii represented the starting point, no significant effects on ontogenetic development and survival following exposure to pCO2 ≥ 7700 ppm were observed. Data suggest that the two first nauplii stages, which are fed endogenously, may be more vulnerable and therefore likely to represent the "bottleneck" for this species in a more acidic ocean. However, the absence of significant effects in the most sensitive stages during exposure to 2800 ppm CO2, a level that is well above worst-case scenario predictions for year 2300 (approximately 2000 ppm CO2), suggests that this species may be generally robust to direct effects of ocean acidification.

  3. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

    Science.gov (United States)

    Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

    2016-08-01

    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

  4. Predation vulnerability of planktonic copepods: consequences of predator foraging strategies and prey sensory abilities

    DEFF Research Database (Denmark)

    Viitasalo, M; Kiørboe, T; Flinkman, J.;

    1998-01-01

    We investigated the vulnerability of 2 copepod species (Eurytemora affinis and Temora longicornis) to predation by predators with different foraging modes, three-spined stickleback Gasterosteus aculeatus juveniles and mysid shrimps Neomysis integer. Copepods were videofilmed escaping from predators...... of the sticklebacks was higher than that of mysids. In the case of sticklebacks foraging on E. affinis, copepod reaction distance was significantly correlated with stickleback approaching speed; sticklebacks captured a copepod only if they were able to slowly approach to within a strike distance of...

  5. Copepod carcasses in a tropical estuary during different hydrographical settings

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Jagadeesan, L.; Lallu, K.R.

    in downstream, which include many species of the Pre-Monsoon community as well as newcomers from the freshwater region. In the entire stretch of the backwaters, carcasses percentage was noticeably higher during the onset of monsoon (Monsoon 1) than the rest..., salinity changed from mesohaline /polyhaline to oligohaline levels in the downstream, during which a mixed copepod community was found consisted of the newcomers from the upstream and also the Pre-Monsoon forms but in less abundance. Noticeably, >80...

  6. Contrasting ecosystem-effects of morphologically similar copepods.

    Directory of Open Access Journals (Sweden)

    Blake Matthews

    Full Text Available Organisms alter the biotic and abiotic conditions of ecosystems. They can modulate the availability of resources to other species (ecosystem engineering and shape selection pressures on other organisms (niche construction. Very little is known about how the engineering effects of organisms vary among and within species, and, as a result, the ecosystem consequences of species diversification and phenotypic evolution are poorly understood. Here, using a common gardening experiment, we test whether morphologically similar species and populations of Diaptomidae copepods (Leptodiaptomus ashlandi, Hesperodiaptomus franciscanus, Skistodiaptomus oregonensis have similar or different effects on the structure and function of freshwater ecosystems. We found that copepod species had contrasting effects on algal biomass, ammonium concentrations, and sedimentation rates, and that copepod populations had contrasting effects on prokaryote abundance, sedimentation rates, and gross primary productivity. The average size of ecosystem-effect contrasts between species was similar to those between populations, and was comparable to those between fish species and populations measured in previous common gardening experiments. Our results suggest that subtle morphological variation among and within species can cause multifarious and divergent ecosystem-effects. We conclude that using morphological trait variation to assess the functional similarity of organisms may underestimate the importance of species and population diversity for ecosystem functioning.

  7. Impact of a power plant cooling system on copepod and meroplankton survival (Bahía Blanca estuary, Argentina Impacto del sistema de enfriamiento de una central termoeléctrica sobre la supervivencia de copépodos y meroplancton (estuario de Bahía Blanca, Argentina

    Directory of Open Access Journals (Sweden)

    Mónica Susana Hoffmeyer

    2005-09-01

    Full Text Available The impact of a power plant cooling system in the Bahía Blanca estuary (Argentina on the survival of target zooplanktonic organisms (copepods and crustacean larvae and on overall mesozooplankton abundance was evaluated over time. Mortality rates were calculated for juveniles and adults of four key species in the estuary: Acartia tonsa Dana, 1849 and Eurytemora americana Williams, 1906 (native and invading copepods, and larvae of the crab Chasmagnathus granulata Dana, 1851 and the invading cirriped Balanus glandula Darwin, 1854. Mean total mortality values were up to four times higher at the water discharge site than at intake, though for all four species, significant differences were only registered in post-capture mortality. The findings show no evidence of greater larval sensitivity. As expected, the sharpest decrease in overall mesozooplankton abundance was found in areas close to heated water discharge.El impacto del sistema de enfriamiento de una planta termoeléctrica ubicada en el estuario de Bahía Blanca, Argentina, fue evaluado en el tiempo, sobre la supervivencia de especies zooplanctónicas seleccionadas (copépodos y larvas de crustáceos y la abundancia general del meso-zooplancton. Se calcularon tasas de mortalidad de juveniles y adultos de cuatro especies clave en el estuario: Acartia tonsa Dana,1849 y Eurytemora americana Williams,1906 (copépodos nativo e invasor, y larvas del cangrejo Chasmagnathus granulata Dana, 1851 y del cirripedio invasor Balanus glandula Darwin, 1854. Los valores medios hallados de la tasa de mortalidad total, fueron hasta cuatro veces más altos en la descarga que en el agua de entrada al sistema. Sin embargo sólo se registraron diferencias significativas entre estos dos sitios, en los valores de mortalidad post-captura obtenidos para las cuatro especies. Los resultados del estudio no demostraron una mayor sensibilidad larval. Como se esperaba, la disminución más pronunciada en la abundancia general

  8. Analysis of the parasitic copepod species richness among Mediterranean fish

    Science.gov (United States)

    Raibaut, André; Combes, Claude; Benoit, Françoise

    1998-06-01

    The Mediterranean ichthyofauna is composed of 652 species belonging to 405 genera and 117 families. Among these, 182 were studied for their parasitic copepods. The analysis of all the works conducted on these crustacea yielded 226 species distributed in 88 genera and 20 families. For each fish species we have established a file providing the species name of the fish, its family, its geographical distribution within the Mediterranean and some of its bio-ecological characteristics. Within each file, all the parasitic copepod species reported on each host species were listed. This allowed to know the species richness (SR) of these hosts. We thus produced 182 files within which 226 copepod species are distributed. A program was created under the Hypercard software, in order to analyse our data. Two parameters were studied. The first one is the mean species richness (MSR), which corresponds to the mean of the different SR found on the different host species. The second is the parasite-host ratio (P/H), which is the ratio of the number of copepod species by the number of host species. These parameters are calculated by our program for all the 182 species of Mediterranean fishes retained in our investigation, on the first hand, and, on the second hand, for one particular group of fish species. We used the following variables to investigate their correlations with copepod species richness: taxonomy—fish families, genera and species; biometry—maximal size of the adult fish; eco-ethology—mode of life (benthic, pelagic or nectonic), displacements (sedentary, migratory with environmental change, or migratory without environmental change), behaviour (solitary or gregarious). Other variables (colour, food, reproduction, abundance, distribution area) were also analysed but did not reveal any clear correlation. Providing that our study does not rely on quantitative (prevalence, intensity) but qualitative basis our aim was only to reveal some tendencies. These tendencies are

  9. Morphometric differences in two calanoid sibling species, Boeckella gracilipes and B. titicacae (Crustacea, Copepoda Diferencias morfométricas en dos especies hermanas Boeckella gracilipes y Boeckella titicacae (Crustacea, Copepoda

    Directory of Open Access Journals (Sweden)

    Patricio De los Ríos Escalante

    2012-12-01

    Full Text Available Calanoid copepods are abundant in South American inland waters and include widespread species, such as Boeckella gracilipes (Daday, 1902, which occurs from the Ecuador to Tierra del Fuego Island. This species occurs under various environmental conditions, and is found in oligotrophic lakes in Patagonia (39-54°S and in shallow mountain lakes north of 39°S. The aim of the present study is to conduct a morphometric comparison of male specimens of B. titicacae collected in Titicaca and B. gracilipes collected in Riñihue lakes, with a third population of B. gracilipes collected in shallow ponds in Salar de Surire. Titicaca and Riñihue lakes are stable environments, whereas Salar de Surire is an extreme environment. These ponds present an extreme environment due to high exposure to solar radiation and high salinity levels. The results of the study revealed differences among the three populations. These results agree well with systematic descriptions in the literature on differences between the populations of Titicaca and Riñihue lakes, and population of Salar de Surire differs slightly from the other two populations. It is probable that the differences between the population of Salar de Surire and the other two populations result from the extreme environment in Salar de Surire. High exposure to solar radiation, high salinity and extreme variations in temperature enhance genetic variations that are consequently expressed in morphology.Los copépodos calanoideos son abundantes en aguas continentales sudamericanas e incluyen especies de amplia distribución geográfica como Boeckella gracilipes (Daday, 1902 que se encuentra desde Ecuador hasta la isla de Tierra del Fuego. Esta especie vive bajo varias condiciones ambientales, y se encuentra en lagos oligotróficos en la Patagonia (39-54°S y en lagunas superficiales de montaña al norte de los 39°S. El objetivo del presente trabajo es realizar un estudio comparativo morfométrico de machos de B

  10. Parasites and diseases in marine copepods: Challenges for future mass-production of live feed for fish larva production

    DEFF Research Database (Denmark)

    Skovgaard, Alf

    Copepods are the natural food for many marine fish larvae, and the use of cultured copepods as life feed is, therefore, becoming increasingly important as more marine fish species are being produced in aquaculture. Large-scale cultivation of copepods may be challenged by diseases and parasites...

  11. Perceiving the algae: How feeding-current feeding copepods detect their nonmotile prey

    DEFF Research Database (Denmark)

    Goncalves, Rodrigo J.; Kiørboe, Thomas

    2015-01-01

    Feeding-current feeding copepods detect and capture prey individually, but the mechanism by which nonmotile prey is detected has been unclear. Early reports that copepods detect phytoplankton prey at distances of one body length or more led to the hypothesis that solutes leaking from the prey wou...

  12. Copepod egg production, moulting and growth rates and secondary production in the Skagerrak in August 1988

    DEFF Research Database (Denmark)

    Peterson, W.T.; Tiselius, P.; Kiørboe, Thomas

    1991-01-01

    Measurements of hydrography, chlorophyll, moulting rates of juvenile copepods and egg production rates of adult female copepods were made at eight stations along a transect across the Skagerrak. The goals of the study were to determine (i) if there were correlations between spatial variations in ...

  13. Active prey selection in two pelagic copepods feeding on potentially toxic and non-toxic dinoflagellates

    DEFF Research Database (Denmark)

    Schultz, Mette; Kiørboe, Thomas

    2009-01-01

    Grazing on two red tide dinoflagellates, the potentially toxic Karenia mikimotoi and the non-toxic Gyrodinium instriatum, was examined in two species of marine copepods, Pseudocalanus elongatus and Temora longicornis. Both copepods cleared K. mikimotoi at rates that were a little lower but compar......Grazing on two red tide dinoflagellates, the potentially toxic Karenia mikimotoi and the non-toxic Gyrodinium instriatum, was examined in two species of marine copepods, Pseudocalanus elongatus and Temora longicornis. Both copepods cleared K. mikimotoi at rates that were a little lower...... but comparable to those at which they cleared the slightly larger G. instriatum when the two dinoflagellates were offered separately. However, when feeding on mixtures of the two prey species, the clearance rates on K. mikimotoi were substantially reduced in both copepods while their clearances of G. instiatum...

  14. Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach

    Science.gov (United States)

    De Troch, M.; Roelofs, M.; Riedel, B.; Grego, M.

    2013-06-01

    Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean). Nematodes were found as the most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia) or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples. The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1) if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2) whether initial (normoxia) feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect) but also of primary producers (indirect effect), with important implications for the recovery phase.

  15. Astaxanthin production in marine pelagic copepods grazing on two different phytoplankton diets

    Science.gov (United States)

    Van Nieuwerburgh, Lies; Wänstrand, Ingrid; Liu, Jianguo; Snoeijs, Pauli

    2005-02-01

    The red carotenoid astaxanthin is a powerful natural antioxidant of great importance in aquatic food webs where it is abundant in eggs and body tissues of fish and crustaceans. Little is known about the impact of the phytoplankton diet on astaxanthin production in copepods, its major pelagic producers. We followed the transfer of carotenoids from phytoplankton to copepods in a mesocosm experiment on the northern Atlantic coast (Norway) and recorded the astaxanthin production in copepods. Wild copepods grazed on nutrient-manipulated phytoplankton blooms, which differed in community composition and nutrient status (nitrogen or silicate limitation). The copepod pigments consisted mainly of free astaxanthin and mono- and diesters of astaxanthin. We found no significant difference in astaxanthin production per copepod individual or per unit C depending on the phytoplankton community. However, in the mesocosms astaxanthin per unit C decreased compared with natural levels, probably through a lower demand for photoprotection by the copepods in the dense phytoplankton blooms. The total astaxanthin production per litre was higher in the silicate-limited mesocosms through increased copepod density. Pigment ratio comparisons suggested that the copepod diet here consisted more of diatoms than in the nitrogen-limited mesocosms. Silicate-saturated diatoms were less grazed, possibly because they could invest more in defence mechanisms against their predators. Our study suggests that the production of astaxanthin in aquatic systems can be affected by changes in nutrient dynamics mediated by phytoplankton community composition and copepod population growth. This bottom-up force may have implications for antioxidant protection at higher trophic levels in the food web.

  16. Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach

    Directory of Open Access Journals (Sweden)

    M. De Troch

    2013-02-01

    Full Text Available Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean. Nematodes were found as most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples. The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1 if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2 whether initial (normoxia feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect but also of primary producers (indirect effect, with important implications for the recovery phase.

  17. Coprophagy in copepods and in a natural zooplankton community

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Kiørboe, Thomas

    Sediment trap studies have revealed that often only a minor fraction of the zooplankton fecal pellet production leave the upper ocean, and it has been suggested that copepod grazing on pellets (coprophagy) is the reason for this. A simple model is here used to estimate rate of coprophagy from lab...... 5 % of the fecal pellet production in the upper 50 m was lost as flux below 50 m depth. Estimates of coprophagy rates showed, however, that the zooplankton community > 200 um could account for only a few percent of the fecal pellet loss. Thus, plankton organisms

  18. The kinematics of swimming and relocation jumps in copepod nauplii

    DEFF Research Database (Denmark)

    Borg, Marc Andersen; Bruno, Eleonora; Kiørboe, Thomas

    2012-01-01

    Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and cop......Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella......, and copepodites are equipped with highly specialized swimming legs. In some species the nauplius may also propel itself more slowly through the water by beating and rotating the appendages in a different, more complex pattern. We use high-speed video to describe jumping and swimming in nauplii of three species...... larger copepodites. A slow-swimming mode is only displayed by T. longicornis. In this mode, beating of the appendages results in the creation of a strong feeding current that is about 10 times faster than the average translation speed of the nauplius. The nauplius is thus essentially hovering when...

  19. Paternal inheritance of the primary sex ratio in a copepod.

    Science.gov (United States)

    Voordouw, M J; Robinson, H E; Anholt, B R

    2005-09-01

    Uniparentally inherited genetic elements are under strong selection to manipulate sex determination in their host and shift the host sex ratio towards the transmitting sex. For any sex-ratio trait, lineage analysis and quantitative genetics are important tools for characterizing the mode of inheritance (biparental vs. maternal vs. paternal) thereby narrowing the field of possible sex-determining mechanisms (e.g. polygenic, sex chromosomes with meiotic drive, cytoplasmic microorganisms). The primary sex ratio of the harpacticoid copepod, Tigriopus californicus is often male-biased and is highly variable among full sib families. We found that this extra-binomial variation for the primary sex ratio is paternally but not maternally transmitted in T. californicus. Paternal transmission of the primary sex ratio has been well documented in the haplo-diploid hymenoptera but is relatively rare in diplo-diploid organisms. If the sex-ratio trait is paternally transmitted in other closely related harpacticoid copepods it would explain why male biased primary sex ratios are so common in this group.

  20. Circular polarization of transmitted light by sapphirinidae copepods.

    Directory of Open Access Journals (Sweden)

    Yuval Baar

    Full Text Available Circularly polarized light, rare in the animal kingdom, has thus far been documented in only a handful of animals. Using a rotating circular polarization (CP analyzer we detected CP in linearly polarized light transmitted through epipelagic free living Sapphirina metallina copepods. Both left and right handedness of CP was detected, generated from specific organs of the animal's body, especially on the dorsal cephalosome and prosome. Such CP transmittance may be generated by phase retardance either in the muscle fibers or in the multilayer membrane structure found underneath the cuticle. Although the role, if any, played by circularly polarized light in Sapphirinidae has yet to be clarified, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication.Planktonic Sapphirinidae copepods were found to circularly polarize the light passing through them. Circular polarization may be created by unique, multilayered features of the membrane structure found under their cuticle or by organized muscle fibers.

  1. [Response of copepod community characteristics to environmental factors in the Backshore Wetland of Expo Garden, Shanghai].

    Science.gov (United States)

    Chen, Li-Jing; Wu, Yan-Fang; Jing, Yu-Xiang; Wang, Cong; Zhang, Yin-Jiang

    2012-11-01

    The Backshore Wetland of Expo Garden was the emphasis of the World Expo construction project in Shanghai in 2010, China programming district. We carried out studies on the community structure and spatial-temporal variation of copepod from September 2009 to August 2010. Statistical Product and Service Solutions (SPSS) was used for relevant statistical analysis between physicochemical parameters and copepod standing crop. Canonical correspondence analysis (CCA) was applied to further explore the correlation between copepod species and environmental parameters using CANOCO 4.5. A total of 23 copepod species in 11 genera, 6 families were identified. 5 dominant species of copepod were recorded during the survey period. They were Eucyclops serrulatus, Thermocyclops taihokuensis, Mesocyclops leuckarti, Thermocyclops brevifurcatus and Microcyclops varicans. The annual mean density of copepod was (8.6 +/- 16.6) ind x L(-1) and the biomass was (0.083 6 +/- 0.143 1) mg x L(-1). The standing crop of copepod had its first peak in July, the second in October and the bottom in January. The highest trophic level was measured at Site 1, decreasing along the flowing direction of the water current, and the lowest level was found at Site 10. The Margelf index remained low in winter and spring, but was increased in summer and autumn. The community structure of copepod was analyzed in relation to water quality parameters by canonical correspondence analysis (CCA). Water temperature, pH, nitrate nitrogen, nitrite nitrogen, TN, TP and dissolved oxygen were strongly correlated with the copepod community structure.

  2. Nutritional quality of two cyanobacteria : How rich is 'poor' food?

    DEFF Research Database (Denmark)

    Schmidt, K.; Jonasdottir, Sigrun

    1997-01-01

    Cyanobacteria have often been described to be nutritionally inadequate and to interfere with zooplankton feeding. In laboratory experiments we offered 2 cyanobacteria, a unicellular Microcystis aeruginosa strain and the filamentous Nodularia sprumigena, to the calanoid copepod Acartia tonsa...... as the sole diet and in food mixtures with the nutritious diatom Thalassiosira weissflogii. Egg production was used as criterion of food quality. The use of cyanobacteria alone was an insufficient diet. However, with increasing additions of M. aeruginosa and N. spumigena to the diatom, different effects were...... observed. Large additions of cyanobacteria resulted in lower egg production and often in elevated mortality of the females, but small additions of M. aeruginosa caused an increase of about 25 % in egg production compared to a pure diatom diet. The influence of similar low concentrations of N. spumigena...

  3. Host-specific and pH-dependent microbiomes of copepods in an extensive rearing system

    DEFF Research Database (Denmark)

    Skovgaard, Alf; Castro Mejia, Josue Leonardo; Hansen, Lars Hestbjerg;

    2015-01-01

    Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copep......Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production...... copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing...

  4. Sex Conversion Induced by Hydrostatic Pressure in the Marine Copepod Tigriopus californicus.

    Science.gov (United States)

    Vacquier, V D; Belser, W L

    1965-12-17

    High hydrostatic pressure applied to the naupliar larval stages of the marine copepod Tigriopus californicus converts some individuals that would have become males into females. The copepodid stages are not sensitive to pressureinduced conversion.

  5. Toxicity of selected pesticides to the groundwater copepod Parastenocaris germanica (Crustacea)

    NARCIS (Netherlands)

    Notenboom J; Boessenkool JJ; ECO

    1994-01-01

    De toxiciteit van negen verschillende bestrijdingsmiddelen of afbraakproducten voor de grondwater copepod Parstenocaris germanica is onderzocht. De onderzochte stoffen zijn geselecteerd vanwege hun potentieel gevaar voor grondwater bewonende metazoen. Niet alle experimenten lieten een duidelijke

  6. Studies of community structure and seasonal dynamics of planktonic copepods in saline-alkaline ponds

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wen; DONG Shuanglin

    2005-01-01

    Species abundance and seasonal succession of copepods in aline-alkaline ponds were studied in Zhaodian Fish Farm, Gaoqing County, Shandong Province, from 5 April 1997 to 1 September 1998. The results indicated that in the conditions of salinity ranging from 1.36 to 20 g/L, total alkalinity changing from 2.4 to 7.2 mmol/L and pH 8-9, zooplankton in saline-alkaline ponds was composed of freshwater salt-tolerated species or halophile species, some of which are halobiont species and usually occurs in freshwater In our study, copepods were predominant in many fish-culture ponds and all control ponds without fishes in spring, late autumn and early winter Dominant species of copepods were Sinocalanus tenellus, Cyclops vicinus, Thermocyclops taihokuensis. The biomass of copepods in the control ponds without fishes was higher than that of the fish-culture ponds. ponds.

  7. On the occurrence of endoparasites from copepods of the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    Occurrence of endoparasitic dinoflagellates belonging to the genera, Blastodinium, parasitizing the coelomic cavity of their host, copepods was investigated. Infection by these species seems to be harmful to the host. Parasitized individuals showed...

  8. Optimal swimming strategies in mate searching pelagic copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2008-01-01

    Male copepods must swim to find females, but swimming increases the risk of meeting predators and is expensive in terms of energy expenditure. Here I address the trade-offs between gains and risks and the question of how much and how fast to swim using simple models that optimise the number...... of lifetime mate encounters. Radically different swimming strategies are predicted for different feeding behaviours, and these predictions are tested experimentally using representative species. In general, male swimming speeds and the difference in swimming speeds between the genders are predicted...... and observed to increase with increasing conflict between mate searching and feeding. It is high in ambush feeders, where searching (swimming) and feeding are mutually exclusive and low in species, where the matured males do not feed at all. Ambush feeding males alternate between stationary ambush feeding...

  9. Heritability of sex tendency in a harpacticoid copepod, Tigriopus californicus.

    Science.gov (United States)

    Voordouw, Maarten J; Anholt, Bradley R

    2002-09-01

    Systems with genetic variation for the primary sex ratio are important for testing sex-ratio theory and for understanding how this variation is maintained. Evidence is presented for heritable variation of the primary sex ratio in the harpacticoid copepod Tigriopus californicus. Variation in the primary sex ratio among families cannot be accounted for by Mendelian segregation of sex chromosomes. The covariance in sex phenotype between full-sibling clutches and between mothers and offspring suggests that this variation has a polygenic basis. Averaged over four replicates, the full-sibling heritability of sex tendency is 0.13 +/- 0.040; and the mother-offspring heritability of sex tendency is 0.31 +/- 0.216. Genetic correlations in the sex phenotype across two temperature treatments indicate large genotype-by-temperature interactions. Future experiments need to distinguish between zygotic, parental, or cytoplasmic mechanisms of sex determination in T. californicus.

  10. Effects of Harpacticus sp. (Harpacticoida, copepod) grazing on dimethylsulfoniopropionate and dimethylsulfide concentrations in seawater

    Science.gov (United States)

    Yu, Juan; Tian, Ji-Yuan; Yang, Gui-Peng

    2015-05-01

    We conducted 9 d and 24 h ingestion experiments to investigate the effects of copepod grazing on the concentrations of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) in seawater. Data from the 9 d trial showed that copepod Harpacticus sp. (Harpacticoida, copepod) grazing increased DMS (0-20%) and dissolved DMSP (DMSPd) (0-128%) apparently, accompanied by a significant reduction of particulate DMSP (DMSPp) in algal culture (0-30%). Ingestion rates (IRs) and pellet production rates (PPRs) of Harpacticus sp. varied with diet species (Platymonas subcordiformis (PS), Nitzschia closterium (NC), Skeletonema costatum (SC), Isochrysis galbana (IG), Prymnesium parvum (PP) or Heterosigma akashiwo (HA)), algal concentration, salinity and temperature. Harpacticus sp. fed on PP showed the lowest IRs (female/male, 0.72/0.53 × 104cells copepod- 1 h- 1) and PPRs (female/male, 0.75/0.5 pellets copepod- 1 h- 1), accompanied with the largest amounts of DMS and DMSPd,p (sum of DMSPd and DMSPp). IRs, PPRs, DMS and DMSPf (DMSP in fecal pellet) increased with the increase of food concentration and peaked at 25 × 104 cells mL- 1I. galbana. High salinity decreased IRs, PPRs, DMS and DMSPf and increased DMSPz (DMSP in copepod body) and DMSPd,p. IRs, PPRs, DMS and DMSPf increased with the increase of temperature from 15 to 25 °C, whereas DMSPz and DMSPd,p contents decreased. Pearson correlation analysis results showed that DMS concentrations presented positive relationships with IRs in algal concentration, salinity and temperature experiments (r = 0.746; P < 0.01). The contribution of DMSPz, DMSPf, DMS and DMSPd,p concentration to the total amounts (DMSPz + DMSPf + DMS + DMSPd,p) was 4-37%, 3-36%, 8-42% and 9-89%, respectively, indicating that DMSP was transferred to copepod tissue and fecal pellet via grazing. Our results are helpful for further understanding of the role of copepod grazing on DMS biogeochemical cycle.

  11. Ocean Acidification Affects the Phyto-Zoo Plankton Trophic Transfer Efficiency.

    Science.gov (United States)

    Cripps, Gemma; Flynn, Kevin J; Lindeque, Penelope K

    2016-01-01

    The critical role played by copepods in ocean ecology and biogeochemistry warrants an understanding of how these animals may respond to ocean acidification (OA). Whilst an appreciation of the potential direct effects of OA, due to elevated pCO2, on copepods is improving, little is known about the indirect impacts acting via bottom-up (food quality) effects. We assessed, for the first time, the chronic effects of direct and/or indirect exposures to elevated pCO2 on the behaviour, vital rates, chemical and biochemical stoichiometry of the calanoid copepod Acartia tonsa. Bottom-up effects of elevated pCO2 caused species-specific biochemical changes to the phytoplanktonic feed, which adversely affected copepod population structure and decreased recruitment by 30%. The direct impact of elevated pCO2 caused gender-specific respiratory responses in A.tonsa adults, stimulating an enhanced respiration rate in males (> 2-fold), and a suppressed respiratory response in females when coupled with indirect elevated pCO2 exposures. Under the combined indirect+direct exposure, carbon trophic transfer efficiency from phytoplankton-to-zooplankton declined to < 50% of control populations, with a commensurate decrease in recruitment. For the first time an explicit role was demonstrated for biochemical stoichiometry in shaping copepod trophic dynamics. The altered biochemical composition of the CO2-exposed prey affected the biochemical stoichiometry of the copepods, which could have ramifications for production of higher tropic levels, notably fisheries. Our work indicates that the control of phytoplankton and the support of higher trophic levels involving copepods have clear potential to be adversely affected under future OA scenarios.

  12. Ocean Acidification Affects the Phyto-Zoo Plankton Trophic Transfer Efficiency

    Science.gov (United States)

    Cripps, Gemma; Flynn, Kevin J.; Lindeque, Penelope K.

    2016-01-01

    The critical role played by copepods in ocean ecology and biogeochemistry warrants an understanding of how these animals may respond to ocean acidification (OA). Whilst an appreciation of the potential direct effects of OA, due to elevated pCO2, on copepods is improving, little is known about the indirect impacts acting via bottom-up (food quality) effects. We assessed, for the first time, the chronic effects of direct and/or indirect exposures to elevated pCO2 on the behaviour, vital rates, chemical and biochemical stoichiometry of the calanoid copepod Acartia tonsa. Bottom-up effects of elevated pCO2 caused species-specific biochemical changes to the phytoplanktonic feed, which adversely affected copepod population structure and decreased recruitment by 30%. The direct impact of elevated pCO2 caused gender-specific respiratory responses in A.tonsa adults, stimulating an enhanced respiration rate in males (> 2-fold), and a suppressed respiratory response in females when coupled with indirect elevated pCO2 exposures. Under the combined indirect+direct exposure, carbon trophic transfer efficiency from phytoplankton-to-zooplankton declined to < 50% of control populations, with a commensurate decrease in recruitment. For the first time an explicit role was demonstrated for biochemical stoichiometry in shaping copepod trophic dynamics. The altered biochemical composition of the CO2-exposed prey affected the biochemical stoichiometry of the copepods, which could have ramifications for production of higher tropic levels, notably fisheries. Our work indicates that the control of phytoplankton and the support of higher trophic levels involving copepods have clear potential to be adversely affected under future OA scenarios. PMID:27082737

  13. Effects of UV radiation on the RNA/DNA ratio of Copepods from Antarctica and Chile

    Institute of Scientific and Technical Information of China (English)

    Paulo F. Lagos; M. Jesús Valdés; Karen Manríquez

    2015-01-01

    The effect of ultraviolet (UV) radiation on marine organisms has been an important focus of recent research, with depletion of the ozone layer resulting in increased UV radiation at high latitudes. Several studies have identiifed negative impacts of UV radiation on the biology of zooplanktonic organisms. This study used the RNA/DNA ratio as a measure of stress in copepod assemblages from Fíldes Bay in Antarctica and Quintay Bay on the central coast of Chile, two areas with high UV radiation but different photobiologic histories. Controlled time-light experiments were performed with copepods from the two locations, exposing them to white light, UV light, or darkness. The results showed different responses to UV radiation. Copepods from Fíldes Bay showed a slow metabolic response to UV radiation after 4 and 8 h of exposure. Copepods from Quintay Bay showed a fast metabolic response after 4 h of exposure (4 orders of magnitude higher than that for Fíldes Bay copepods) followed by a rapid return toward baseline after 8 h of exposure. These different responses probably relfect the time the copepod assemblages have been exposed to increased UV radiation and the extent of adaptive stress responses to cope with that increased UV radiation. The results of this study show that the RNA/DNA ratio is a useful indicator of the physiologic status of marine organisms and is a useful tool to measure the effects of changing environmental conditions on marine ecosystems, such as those associated with global climate change.

  14. A Lagrangian model of Copepod dynamics: clustering by escape jumps in turbulence

    CERN Document Server

    Ardeshiri, Hamidreza; Schmitt, François G; Souissi, Sami; Toschi, Federico; Calzavarini, Enrico

    2016-01-01

    Planktonic copepods are small crustaceans that have the ability to swim by quick powerful jumps. Such an aptness is used to escape from high shear regions, which may be caused either by flow per- turbations, produced by a large predator (i.e. fish larvae), or by the inherent highly turbulent dynamics of the ocean. Through a combined experimental and numerical study, we investigate the impact of jumping behaviour on the small-scale patchiness of copepods in a turbulent environment. Recorded velocity tracks of copepods displaying escape response jumps in still water are here used to define and tune a Lagrangian Copepod (LC) model. The model is further employed to simulate the behaviour of thousands of copepods in a fully developed hydrodynamic turbulent flow obtained by direct numerical simulation of the Navier-Stokes equations. First, we show that the LC velocity statistics is in qualitative agreement with available experimental observations of copepods in tur- bulence. Second, we quantify the clustering of LC...

  15. Grazer-induced chain lenght plasticity reduces grazing risk in a marine diatom

    DEFF Research Database (Denmark)

    Bergkvist, Johanna; Thor, Peter; Jakobsen, Hans Henrik;

    2012-01-01

    We show that Skeletonema marinoi suppresses chain formation in response to copepod cues. The presence of three different copepod species (Acartia tonsa, Centropages hamatus, or Temora longicornis) significantly reduced chain length. Furthermore, chain length was significantly reduced when S. mari...

  16. Mandibular gnathobases of marine planktonic copepods – feeding tools with complex micro- and nanoscale composite architectures

    Directory of Open Access Journals (Sweden)

    Jan Michels

    2015-03-01

    Full Text Available Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type α-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods’ dominance of the marine zooplankton observed today.

  17. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    Science.gov (United States)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  18. Use of the copepod Oithona hebes as a bioencapsulator of essential fatty acids

    Directory of Open Access Journals (Sweden)

    Marcia Vanacor Barroso

    2015-09-01

    Full Text Available AbstractThe advantages of using copepods in aquaculture include nutritional superiority, high digestibility and broad spectrum of sizes, with the possibility of bioencapsulation of nutrients, probiotics and medicines. This study aimed to compare the effects of feeding copepods with a microalgae diet and two commercial inert diets on the copepod culture performance and their fatty acid profile. Wild copepods were collected in the estuarine system of Piraquê-açu River, Aracruz, Espírito Santo, Brazil, with a conical net of 60 cm in diameter and 200 μm mesh with a blind cup end, towed through the subsurface layer at a speed of 1 knot for 5 minutes. Once collected, the material was sieved in order to select only Oithona hebes. The experiment was conducted in nine cylindrical-conical tanks with a 60 L capacity, salinity of 25.8 ± 1.3, temperature of 25.5 ± 0.5 ºC and weak aeration, stocked with a density of 1.5 copepod/mL. Treatments were made in triplicate and consisted of: Treatment 1 (Control fed with microalgae Chaetoceros gracilis and Nannochloropsis oculata (1:1 with 50,000 cells.mL-1each; Treatment 2 with S.Parkle® INVE (1g.million-1; and Treatment 3 with freeze-dried spirulina (1g.million-1. The mean final population was compared by a Tukey test (p < 0.05. Results showed higher population growth for copepods treated with S.parkle, which was the only treatment that presented copepodites. S.parkle was a good source of total lipids (9.54 g.100g-1 dry weight, high availability of DHA, EPA and had a good DHA:EPA:ARA ratio of 12.4:3.4:1.0. Copepods that were fed S.parkle had the highest DHA levels and a DHA:EPA:ARA ratio of 15.4:2.2:1.0. This study showed that S.parkle is a good inert food for rearing the copepod O. hebes, demonstrating the ability of copepods to bioencapsulate nutrients, allowing their transfer in the food chain.

  19. Impacts of ontogenetically migrating copepods on downward carbon flux in the western subarctic Pacific Ocean

    Science.gov (United States)

    Kobari, Toru; Steinberg, Deborah K.; Ueda, Ai; Tsuda, Atsushi; Silver, Mary W.; Kitamura, Minoru

    2008-07-01

    To evaluate the impacts of ontogenetically (seasonally) migrating copepods on carbon transport to the mesopelagic zone, we investigated depth distribution, population structure, and feeding activity of the ontogentic copepod community in the western subarctic Pacific Ocean from day-night pairs of zooplankton samples down to 1000 m during the VERtical Transport In the Global Ocean (VERTIGO) program. Over the 31 July-16 August 2005 study period, the biomass of Neocalanus cristatus and Neocalanus plumchrus predominated in the near surface waters, while Neocalanus flemingeri was already dormant at depth. We observed a strong diel migration for Metridia pacifica, and a seasonal downward migration for Eucalanus bungii. Based on gut pigment analysis, ingestion rate of the copepod community was 214-375 mg C m -2 day -1, which was equal to 26-37% of the concurrent primary production. However, comparison of grazing estimated from gut pigments to calculated carbon demand of the copepod community indicates that phytoplankton comprised 37-59% of the ingested carbon. Thus, the copepod community appears to have also relied on detritus and microzooplankton for their nutrition, likely because primary production during this time was dominated by picophytoplankton too small to be grazed by these large copepods. Fecal pellet flux by the copepod community was estimated to account for 141-223% of the sedimentary particulate organic carbon (POC) flux at 150 m, suggesting considerable fragmentation and consumption of pellets in the upper layers. Fecal pellets alone were adequate to meet copepod carbon demand in the surface 0-150 m layer. Active carbon flux by diel migration of M. pacifica (respiration, egestion, and mortality) was 4-17 mg C m -2 day -1, equal to 6-44% of sedimentary POC flux at 150 m. Active carbon flux by N. flemingeri ontogenetic migration (i.e., respiration and mortality at depth) contributed 246 mg C m -2 year -1, equal to 9% of sedimentary POC flux at 1000 m. The

  20. Hydrodynamic and Sensory Factors Governing Response of Copepods to Simulated Predation by Balaenid Whales

    Directory of Open Access Journals (Sweden)

    Alexander J. Werth

    2012-01-01

    Full Text Available Predator/prey interactions between copepods and balaenid (bowhead and right whales were studied with controlled lab experiments using moving baleen in still water and motionless baleen in flowing water to simulate zooplankton passage toward, into, and through the balaenid oral cavity. Copepods showed a lesser escape response to baleen and to a model head simulating balaenid oral hydrodynamics than to other objects. Copepod escape response increased as water flow and body size increased and was greatest at distances ≥10 cm from baleen and at copepod density = 10,000 m−3. Data from light/dark experiments suggest that escape is based on mechanoreception, not vision. The model head captured 88% of copepods. Results support previous research showing hydrodynamic effects within a whale’s oral cavity create slight suction pressures to draw in prey or at least preclude formation of an anterior compressive bow wave that could scatter or alert prey to the presence of the approaching whale.

  1. The effect of Fucus vesiculosus on the grazing of harpacticoid copepods on diatom biofilms

    Science.gov (United States)

    De Troch, M.; Chepurnov, V. A.; Vincx, M.; Ólafsson, E.

    2008-10-01

    The effect of Fucus vesiculosus on the functional traits of three harpacticoid copepod species ( Tigriopus brevicornis, Paramphiascella fulvofasciata and Microarthridion littorale) was studied. These copepods are likely to be important grazers on biofilms consisting mainly of diatoms. Several microcosms were created using diatom cultures ( Navicula phyllepta and Seminavis robusta) and vegetative thalli of Fucus, with the biofilm associated, collected from the field. The diatoms were enriched in the stable carbon 13C to facilitate tracing in the harpacticoids. The biofilm on the Fucus was labeled through impregnation of the Fucus leaves in 13C enriched seawater. In all treatments a measurable uptake of diatoms was found for the three copepod species. All copepods showed a low uptake of labeled material when only Fucus thalli were available. The grazing on the benthic diatoms was negatively affected by the presence of the Fucus thalli in the case of P. fulvofasciata. One species, T. brevicornis, grazed efficiently both on sedimentary and epiphytic biofilms. We hereby proved experimentally that benthic harpacticoid copepods are able to switch their food uptake under different habitat/food circumstances. This variety of food uptake is an illustration of the so-called 'niche complementarity effect' that lies at the basis of diverse communities.

  2. Climate change affects low trophic level marine consumers: warming decreases copepod size and abundance.

    Science.gov (United States)

    Garzke, Jessica; Ismar, Stefanie M H; Sommer, Ulrich

    2015-03-01

    Concern about climate change has re-ignited interest in universal ecological responses to temperature variations: (1) biogeographical shifts, (2) phenology changes, and (3) size shifts. In this study we used copepods as model organisms to study size responses to temperature because of their central role in the pelagic food web and because of the ontogenetic length constancy between molts, which facilitates the definition of size of distinct developmental stages. In order to test the expected temperature-induced shifts towards smaller body size and lower abundances under warming conditions, a mesocosm experiment using plankton from the Baltic Sea at three temperature levels (ambient, ambient +4 °C, ambient -4 °C) was performed in summer 2010. Overall copepod and copepodit abundances, copepod size at all life stages, and adult copepod size in particular, showed significant temperature effects. As expected, zooplankton peak abundance was lower in warm than in ambient treatments. Copepod size-at-immature stage significantly increased in cold treatments, while adult size significantly decreased in warm treatments.

  3. Tumour-like anomaly of copepods-an evaluation of the possible causes in Indian marine waters

    Digital Repository Service at National Institute of Oceanography (India)

    Jagadeesan, L.; Jyothibabu, R.

    so far to prove conclusively the mechanism involved in developing TLA in copepods. TLA in copepods are considered as a potential threat to the well-being of the aquatic food web, which prompted us to assess these abnormalities in Indian marine waters...

  4. Multiple vs. single phytoplankton species alter stoichiometry of trophic interaction with zooplankton.

    Science.gov (United States)

    Plum, Christoph; Hüsener, Matthias; Hillebrand, Helmut

    2015-11-01

    Despite the progress made in explaining trophic interactions through the stoichiometric interplay between consumers and resources, it remains unclear how the number of species in a trophic group influences the effects of elemental imbalances in food webs. Therefore, we conducted a laboratory experiment to test the hypothesis that multispecies producer assemblages alter the nutrient dynamics in a pelagic community. Four algal species were reared in mono- and polycultures under a 2 x 2 factorial combination of light and nutrient supply, thereby contrasting the stoichiometry of trophic interactions involving single vs. multiple producer species. After 9 d, these cultures were fed to the calanoid copepod Acartia tonsa, and we monitored biomass, resource use, and C:N:P stoichiometry in both phyto- and zooplankton. According to our expectations, light and N supply resulted in gradients of phytoplankton biomass and nutrient composition (C:N:P). Significant net diversity effects for algal biomass and C:N:P ratios reflected the greater responsiveness of the phytoplankton polyculture to altered resource supply compared to monocultures. These alterations of elemental ratios were common, and were partly triggered by changes in species frequency in the mixtures and partly by diversity-related changes in resource use. Copepod individual biomass increased under high light (HL) and N-reduced (-N) conditions, when food was high in C:N but low in C:P and N:P, whereas copepod growth was obviously P limited, and copepod stoichiometry was not affected by phytoplankton elemental composition. Correspondingly, copepod individual biomass reflected significant net diversity effects: compared to expectations- derived from monocultures, copepod individuals feeding on algal polycultures remained smaller than predicted under HL and N-sufficient (+N) conditions but grew larger than predicted under HL, -N and low light +N conditions. In conclusion, multiple producer species altered the

  5. Seasonal variation and longitudinal distribution of copepods in the main river area of the Three Gorges Reservoir

    Institute of Scientific and Technical Information of China (English)

    Jianliang YAO; Junzeng XUE; Dengyuan WANGt; Qinghua CAI; Xiangfei HUANG; Jiankang LIU

    2008-01-01

    The ecosystem of the Three Gorges in the Yangtze River was changed into an artificial lake (res-ervoir) ecosystem after impoundment in June 2003. We surveyed the seasonal variation and spatial distribution of copepods from April 2004 to January 2005 in order to provide data for clarifying the successional pattern of the ecosystem. From Jiangjin to Maoping, eight copepod species were collected and classified into Calanoida (2), Harpacticoida (1), and Cyclopoida (5). Among them, Mesocyclops pehpeiensis, M. leuckarti and Sinocalanus dorrii had a relatively wide distribution. No distinct dif-ference in species number was found among the sampling sites, but the species composition was different. Species composition, distribution and density of copepods showed significant seasonal variations. In addition, cope-pod density showed an obvious gradient with the distance from the reservoir dam: the nearer to the dam, the denser the copepods.

  6. Physiological response of the intertidal copepod Tigriopus japonicus experimentally exposed to cadmium

    Directory of Open Access Journals (Sweden)

    Emadeldeen H. Mohammed

    2011-01-01

    Full Text Available The intertidal harpacticoid copepod Tigriopus japonicus is a benthic copepod and has beencommonly used in ecotoxicology and environmental genomics studies as a marine model species. In thisstudy, Laboratory experiments were conducted to investigate the effects of cadmium (Cd on survival,development, growth and reproductive performance of T.japonicus. Our results indicated that Cd wassignificantly affected adult survival and development, but not those of nauplii. Despite the reduction inadult female total body length, Cd was not significantly affected copepod growth. Concerning T.japonicusreproduction response, Cd was significantly reduced the number of nauplii produced at 10 μg L-1. Thus,survival, development and reproduction in T.japonicus as a model test species could be effectivephysiological markers to monitor marine metal pollution and to assess population response.

  7. Feeding habits of European pilchard late larvae in a nursery area in the Adriatic Sea

    Science.gov (United States)

    Borme, Diego; Tirelli, Valentina; Palomera, Isabel

    2013-04-01

    European pilchard Sardina pilchardus late larvae were collected in the Gulf of Manfredonia, an important nursery area, during their seasonal inshore occurrence. Thanks to diel cycle sampling and to the wide range of larval lengths (from a minimum of 27 mm to a maximum of 45 mm), both feeding rhythm and ontogenetic changes were analysed. The feeding peak was observed in the afternoon, before sunset. Sardine larvae were exclusively zooplanktivorous, their diet being based on Calanoid Copepods from the genus Paracalanus (IRI% = 65.7), on the species Temora longicornis (IRI% = 15.5) and other small-sized Copepods. Other planktonic organisms appeared in the stomach contents occasionally and never reached IRI% values > 1. The number of prey per stomach increased suddenly at larval lengths around 40 mm, corresponding to the development of the stomach. Prey composition in the environment was established by contemporaneous sampling of plankton, performed by means of two plankton nets with different meshes. The main prey items were positively selected among those available in the field, but some other prey (Centropages spp., Harpacticoids, Corycaeids, Temora stylifera and Acartia spp.) were also preferred, although rare in the plankton samples. In contrast, copepod nauplii, despite their abundance in the environment (15,848 ± 4441 individuals m- 3), were only occasionally recovered in the larval gut contents (N = 0.26%). This shows that sardine late larvae have switched to larger prey items.

  8. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

    Directory of Open Access Journals (Sweden)

    Jessica Garzke

    Full Text Available Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5 and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA and arachidonic acid (ARA to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

  9. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content

    Science.gov (United States)

    Hansen, Thomas; Ismar, Stefanie M. H.; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  10. Use of phytoplankton pigments in estimating food selection of three marine copepods

    DEFF Research Database (Denmark)

    Oechsler-Christensen, B.; Jonasdottir, Sigrun; Henriksen, P.;

    2012-01-01

    . Traditional grazing experiments were carried out in parallel with pigment analysis in experiments where the copepod A. tonsa was exposed to a mixture of food organisms. The results demonstrated that the two methods gave similar results with regard to food selection and that with certain precautions, pigment...... analysis can be successfully used in food selection studies......Experiments were carried out to test the use of algal pigments in zooplankton grazing studies with a special emphasis on estimation of food selection. The results demonstrated that pigment composition of the phytoplankton food was reflected closely in the three copepod species Centropages typicus...

  11. Solid phase extraction and metabolic profiling of exudates from living copepods

    DEFF Research Database (Denmark)

    Selander, Erik; Heuschele, Jan; Nylund, Göran M.;

    2016-01-01

    Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we....... Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude...

  12. Prevalence of the parasitic copepod Haemobaphes intermedius on juvenile buffalo sculpins from Washington State

    Science.gov (United States)

    Halpenny, C.M.; Kocan, R.M.; Hershberger, P.K.

    2004-01-01

    The parasitic copepod, Haemobaphes intermedius, was detected in 62% of juvenile buffalo sculpins Enophrys bison, a previously unreported host, from the San Juan Islands archipelago in Washington State. Most infestations were characterized by the presence of a single female copepod infestations with multiple H. intermedius occurred either unilaterally or bilaterally in 29% of parasitized individuals. Impaired condition of parasitized hosts was indicated by significantly lower total lengths and weights (34.9 mm; 1.6 g) than in unparasitized cohorts (38.9 mm; 2.1 g). Host specificity was indicated by the failure to detect H. intermedius in 43 sympatric great sculpins Myoxocephalus polyacanthocephalus from the same location.

  13. Miocene cyclopid copepod from a saline paleolake in Mojave, California

    Directory of Open Access Journals (Sweden)

    Maria Hołyńska

    2016-06-01

    Full Text Available There are remarkably few direct fossil records of Copepoda, which implies that current estimates of the lineage divergence times and inferences on the historical biogeography remain highly dubious for these small-sized crustaceans. The Cyclopidae, a predominantly freshwater copepod family with 1000+ species and distributed worldwide, has no fossil record at all. Recent collections from the middle Miocene Barstow Formation in Southern California resulted in ample material of finely preserved cyclopid fossils, including both adult and larval stages. To document the antennulary setation pattern in the adult and copepodid instars we used a coding system that is coherent between sexes and developmental stages. The majority of the cyclopid fossils, coming from saline lake environment, represent the modern genus Apocyclops, a euryhaline, thermophilic group occurring both in the New World and Old World. A new species Apocyclops californicus is described, based on the short medial spine and spiny ornamentation of the free segment of leg 5, spinule ornamentation of pediger 5, and well-developed protuberances of the intercoxal sclerite of leg 4. The presence of antennal allobasis and the features of the swimming legs unambiguously place the Miocene Apocyclops in the A. panamensis-clade, a predominantly amphi-Pacific group. The middle Miocene fossils with clear affinities to a subgroup of Apocyclops imply an early Miocene or Paleogene origin of the genus. Based on the geographic patterns of the species richness and morphology in Apocyclops and its presumed closest relative, genus Metacyclops, we hypothesize that: (i the ancestor of Apocyclops, similar in morphology to some cave-dweller Metacyclops occurring today in the peri-Mediterranean region, might have arrived in North America from Europe via the Thulean North Atlantic bridge in the late Paleocene–early Eocene; (ii Eocene termination of the Thulean land connection might have resulted in the

  14. Tumour-like anomaly of copepods-an evaluation of the possible causes in Indian marine waters.

    Science.gov (United States)

    Jagadeesan, L; Jyothibabu, R

    2016-04-01

    Globally, tumour-like anomalies (TLA) in copepods and the critical assessment of their possible causes are rare. The exact causative factor and ecological consequences of TLA in copepods are still unclear and there is no quantitative data available so far to prove conclusively the mechanism involved in developing TLA in copepods. TLA in copepods are considered as a potential threat to the well-being of the aquatic food web, which prompted us to assess these abnormalities in Indian marine waters and assess the possible etiological agents. We carried out a focused study on copepods collected from 10 estuarine inlets and five coastal waters of India using a FlowCAM, advanced microscopes and laboratory-incubated observations. The analysis confirmed the presence of TLA in copepods with varying percentage of incidence in different environments. TLA was recorded in 24 species of copepods, which constituted ~1-15 % of the community in different environments. TLA was encountered more frequently in dominant copepods and exhibited diverse morphology; ~60 % was round, dark and granular, whereas ~20 % was round/oval, transparent and non-granular. TLA was mostly found in the dorsal and lateral regions of the prosome of copepods. The three suggested reasons/assumptions about the causes of TLA such as ecto-parasitism (Ellobiopsis infection), endo-parasitism (Blastodinium infection) and epibiont infections (Zoothamnium and Acineta) were assessed in the present study. We did find infections of endo-parasite Blastodinium, ecto-parasite Ellobiopsis and epibiont Zoothamnium and Acineta in copepods, but these infectious percentages were found <1.5 % to the total density and most of them are species specific. Detailed microscopical observations of the samples collected and the results of the incubation experiments of infected copepods revealed that ecto-parasitism, endo-parasitism and epibiont infections have less relevance to the formation of TLA in copepods. On the other hand

  15. Prevalent ciliate symbiosis on copepods: high genetic diversity and wide distribution detected using small subunit ribosomal RNA gene.

    Science.gov (United States)

    Guo, Zhiling; Liu, Sheng; Hu, Simin; Li, Tao; Huang, Yousong; Liu, Guangxing; Zhang, Huan; Lin, Senjie

    2012-01-01

    Toward understanding the genetic diversity and distribution of copepod-associated symbiotic ciliates and the evolutionary relationships with their hosts in the marine environment, we developed a small subunit ribosomal RNA gene (18S rDNA)-based molecular method and investigated the genetic diversity and genotype distribution of the symbiotic ciliates on copepods. Of the 10 copepod species representing six families collected from six locations of Pacific and Atlantic Oceans, 9 were found to harbor ciliate symbionts. Phylogenetic analysis of the 391 ciliate 18S rDNA sequences obtained revealed seven groups (ribogroups), six (containing 99% of all the sequences) belonging to subclass Apostomatida, the other clustered with peritrich ciliate Vorticella gracilis. Among the Apostomatida groups, Group III were essentially identical to Vampyrophrya pelagica, and the other five groups represented the undocumented ciliates that were close to Vampyrophrya/Gymnodinioides/Hyalophysa. Group VI ciliates were found in all copepod species but one (Calanus sinicus), and were most abundant among all ciliate sequences obtained, indicating that they are the dominant symbiotic ciliates universally associated with copepods. In contrast, some ciliate sequences were found only in some of the copepods examined, suggesting the host selectivity and geographic differentiation of ciliates, which requires further verification by more extensive sampling. Our results reveal the wide occurrence and high genetic diversity of symbiotic ciliates on marine copepods and highlight the need to systematically investigate the host- and geography-based genetic differentiation and ecological roles of these ciliates globally.

  16. Prevalent ciliate symbiosis on copepods: high genetic diversity and wide distribution detected using small subunit ribosomal RNA gene.

    Directory of Open Access Journals (Sweden)

    Zhiling Guo

    Full Text Available Toward understanding the genetic diversity and distribution of copepod-associated symbiotic ciliates and the evolutionary relationships with their hosts in the marine environment, we developed a small subunit ribosomal RNA gene (18S rDNA-based molecular method and investigated the genetic diversity and genotype distribution of the symbiotic ciliates on copepods. Of the 10 copepod species representing six families collected from six locations of Pacific and Atlantic Oceans, 9 were found to harbor ciliate symbionts. Phylogenetic analysis of the 391 ciliate 18S rDNA sequences obtained revealed seven groups (ribogroups, six (containing 99% of all the sequences belonging to subclass Apostomatida, the other clustered with peritrich ciliate Vorticella gracilis. Among the Apostomatida groups, Group III were essentially identical to Vampyrophrya pelagica, and the other five groups represented the undocumented ciliates that were close to Vampyrophrya/Gymnodinioides/Hyalophysa. Group VI ciliates were found in all copepod species but one (Calanus sinicus, and were most abundant among all ciliate sequences obtained, indicating that they are the dominant symbiotic ciliates universally associated with copepods. In contrast, some ciliate sequences were found only in some of the copepods examined, suggesting the host selectivity and geographic differentiation of ciliates, which requires further verification by more extensive sampling. Our results reveal the wide occurrence and high genetic diversity of symbiotic ciliates on marine copepods and highlight the need to systematically investigate the host- and geography-based genetic differentiation and ecological roles of these ciliates globally.

  17. Trophic interactions and productivity of copepods as live feed from tropical Taiwanese outdoor aquaculture ponds

    DEFF Research Database (Denmark)

    Blanda, Elisa; Drillet, Guillaume; Huang, Cheng-Chien;

    2015-01-01

    , respectively. P. annandalei's specific growth rate in the ponds, thus the secondary productivity, was 0.89 ± 0.1 d− 1 (average ± S.D.). The average harvest (21 kg of copepods wet weight per pond every second to fifth day), was a relatively low quantity to satisfy the demand of the fish farmers, especially...

  18. Ostrincola breviseti n. sp., a copepod parasite of an oyster from Penang, Malaysia

    NARCIS (Netherlands)

    Ho, Ju-shey; Kim, Il-Hoi

    1990-01-01

    A new species of poecilostomatoid copepod, Ostrincola breviseti, is described from the mantle cavity of the oyster, Saccostrea cucullata (Born), collected at Penang, Malaysia. The new species is distinguished by the short terminal setae on leg 5. The species of Ostrincola are discussed in terms of t

  19. The use of chlorine dioxide for the inactivation of copepod zooplankton in drinking water treatment.

    Science.gov (United States)

    Lin, Tao; Chen, Wei; Cai, Bo

    2014-01-01

    The presence of zooplankton in drinking water treatment system may cause a negative effect on the aesthetic value of drinking water and may also increase the threat to human health due to they being the carriers of bacteria. Very little research has been done on the effects of copepod inactivation and the mechanisms involved in this process. In a series of bench-scale experiments we used a response surface method to assess the sensitivity of copepod to inactivation when chlorine dioxide (ClO₂) was used as a disinfectant. We also assessed the effects of the ClO₂dosage, exposure time, organic matter concentration and temperature. Results indicated that the inactivation rate improved with increasing dosage, exposure time and temperature, whereas it decreased with increasing organic matter concentration. Copepod inactivation was more sensitive to the ClO₂dose than that to the exposure time, while being maintained at the same Ct-value conditions. The activation energy at different temperatures revealed that the inactivation of copepods with ClO₂was temperature-dependent. The presence of organic matter resulted in a lower available dose as well as a shorter available exposure time, which resulted in a decrease in inactivation efficiency.

  20. Effects of copepod size on fish growth: A model based on data for North Sea sandeel

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Jørgensen, C.; Fiksen, Ø.

    2015-01-01

    mechanistic models from relevant data: (1) a model of the bioenergetics and stomach filling/evacuation dynamics, and (2) a Holling type II functional response model that encompasses visual range from basic principles. The model predicts that going from a situation where large Calanus copepods (2 mm) dominate...

  1. Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic

    DEFF Research Database (Denmark)

    Jonasdottir, Sigrun; Visser, Andre; Richardson, Katherine

    2015-01-01

    Significance Every autumn across the North Atlantic, large numbers of zooplankton copepods migrate from the surface waters into the ocean's interior to hibernate at depths of 600–1,400 m. Through this migration, they actively transport lipid carbon to below the permanent thermocline, where it is ...

  2. Non-consumptive effects of predator presence on copepod reproduction: insights from a mesocosm experiment

    DEFF Research Database (Denmark)

    Heuschele, Jan; Ceballos, Sara; Borg, Marc Andersen;

    2014-01-01

    Reproduction in planktonic animals depends on numerous biotic and abiotic factors. One of them is predation pressure, which can have both direct consumptive effects on population density and sex ratio, and non-consumptive effects, for example on mating and migration behaviour. In copepods, predat...

  3. Feeding season duration and the relative success of capital and income spawning copepods

    DEFF Research Database (Denmark)

    Sainmont, Julie; Varpe, Øystein; Andersen, Ken Haste;

    to the spring bloom, using only its reserves accumulated the previous year (capital breeder). The success of these two strategies is related to the length of the spring bloom, the only source of nutrients for these copepods. We use an individual based model to approach the question of income versus capital...

  4. Physiological improvement in the copepod Eurytemora affinis through thermal and multi-generational selection

    DEFF Research Database (Denmark)

    Souissi, Anissa; Souissi, Sami; Hansen, Benni Winding

    2016-01-01

    . First two different copepod lines were obtained after long-term culture at constant cold (7°C) and warm (20°C) temperatures. Then both populations were transferred to a higher temperature of 24°C appropriate for aquaculture use and followed during five generations. During the first two generations (F1–F...

  5. Population dynamic of high latitude copepods - with emphasis on Metridia longa

    DEFF Research Database (Denmark)

    Kjellerup, Sanne

    2014-01-01

    High latitude ecosystems are shaped by seasonality in light, ranging from complete darkness in winter to midnight sun in summer, influencing both temperature and primary production. Copepods are important grazers on phytoplankton in marine systems and occupy a central role in the marine food-web...

  6. Extreme temperature and oil contamination shape the relative abundance of copepod species in the Arctic

    DEFF Research Database (Denmark)

    Dinh, Khuong Van; Nielsen, Torkel Gissel

    is of north Atlantic origin. Pyrene is one of the most toxic components of crude oil to marine copepods. The temperatures of 2, 6 and 10°C represent the mean sea water temperature, the 4°C increase in mean temperature by 2100 as predicted by IPCC scenario RCP8.5 (2013) and the extreme sea water temperature...

  7. Synopsis of lichomolgid copepods (Poecilostomatoida) associated with soft corals (Alcyonacea) in the tropical Indo-Pacific

    NARCIS (Netherlands)

    Humes, A.G.

    1990-01-01

    A synopsis of the 97 species of lichomolgid copepods known to be associated with tropical IndoPacific shallow-water alcyonaceans is given (Madagascar, New Caledonia, Moluccas, Philippines, and Enewetak Atoll). One new genus and 29 new species are included, distributed among the lichomolgid genera Ac

  8. The parasitic copepod Lernaeocera branchialis negatively affects cardiorespiratory function in Gadus morhua

    DEFF Research Database (Denmark)

    Behrens, Jane W.; Seth, H.; Axelsson, M.

    2014-01-01

    The parasitic copepod Lernaeocera branchialis had a negative effect on cardiorespiratory function in Atlantic cod Gadus morhua such that it caused pronounced cardiac dysfunction with irregular rhythm and reduced stroke amplitude compared with uninfected fish. In addition, parasite infection...... depressed the postprandial cardiac output and oxygen consumption...

  9. Dissonus pastinum n. sp. (Siphonostomatoida: Dissonidae), a copepod parasitic on a horn shark from Japan

    NARCIS (Netherlands)

    Deets, Gregory B.; Dojiri, Masahiro

    1990-01-01

    A new species of siphonostomatoid copepod, Dissonus pastinum, is described from the horn shark, Heterodontus japonicus (Dumeril), from Awa, Japan. The new species differs from all congeners except D. ruvetti Nunes-Ruivo & Fourmanoir, 1956 and D. nudiventris Kabata, 1965 by the presence of the sterna

  10. First records of parasitic copepods (Crustacea, Siphonostomatoida) from marine fishes in Korea.

    Science.gov (United States)

    Venmathi Maran, B A; Soh, H Y; Hwang, U W; Chang, C Y; Myoung, J G

    2015-06-01

    The knowledge of the biodiversity of parasitic copepods in South Korea is increasing. Interestingly we report here, some parasitic copepods considered as the first record of findings from Korea. Nine species of parasitic copepods (Siphonostomatoida) including six genera of three different families [Caligidae (7), Lernaeopodidae (1), Lernanthropidae (1)] were recovered from eight species of wild fishes in Korea: 1) Caligus hoplognathi Yamaguti & Yamasu, 1959 (♀, ♂) from the body surface of barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel); 2) Caligus lagocephali Pillai, 1961 (♀) from the gills of panther puffer Takifugu pardalis (Temminck & Schlegel); 3) Euryphorus brachypterus (Gerstaecker, 1853) (♀, ♂) from the opercular cavity of Atlantic bluefin tuna Thunnus thynnus (Linnaeus); 4) Euryphorus nordmanni Milne Edwards, 1840 (♀, ♂) from the opercular cavity of common dolphin fish Coryphaena hippurus Linnaeus; 5) Gloiopotes huttoni (Thomson) (♀, ♂) from the body surface of black marlin Istiompax indica (Cuvier); 6) Lepeophtheirus hapalogenyos Yamaguti & Yamasu, 1959 (♀) from the gill filaments of O. fasciatus; 7) Lepeophtheirus sekii Yamaguti, 1936 (♀, ♂) from the body surface of red seabream Pagrus major (Temminck & Schlegel); 8) Brachiella thynni Cuvier, 1830 (♀) from the body surface of longfin tuna or albacore Thunnus alalunga (Bonnaterre); 9) Lernanthropinus sphyraenae (Yamaguti & Yamasu, 1959) (♀) from the gill filaments of moon fish Mene maculata (Bloch & Schneider). Since the female was already reported in Korea, it is a new record for the male of C. hoplognathi. A checklist for the parasitic copepods of the family Caligidae, Lernaeopodidae and Lernanthropidae of Korea is provided.

  11. Estructura genética del copépodo Acartia lilljeborgii en la costa del estado de Yucatán, México

    Directory of Open Access Journals (Sweden)

    Jorge Tello-Cetina

    2013-11-01

    Full Text Available Se determinó la estructura genética poblacional y sus implicancias dentro de la cadena trófica del copépodo Acartia lilljeborgii en la costa de Yucatán, mediante el uso de isoenzimas y su posterior determinación por electroforesis. Nueve sistemas se expresaron con un máximo de 30 loci. El polimorfismo y heterocigosis de las poblaciones estudiadas, al ser comparados con otras especies de copépodos, resultaron ser bajos y de los cuatro loci que presentaron variación, solo los loci EST2 y PGM1 se expresaron en todos los sitios de muestreo. La PGM1 presentó el mayor valor de heterocigosis (0,4728 y la GPI1 fue la de menor valor (0,3200. Ningún sistema se apartó de la condición de equilibrio de Hardy-Weinberg. Los valores de FST estuvieron entre los valores de -0,0798 para PGM1 y de 0,5899 para FBP1. Las tres poblaciones de A. lilljeborgii analizadas en la costa de Yucatán, presentaron una baja variabilidad y diferenciación genética entre las poblaciones, como lo indican los valores de distancia genética de 0,0585 que fue el mayor para las poblaciones de Chelem y de Río Lagartos, lo que sugiere que estas poblaciones están parcialmente aisladas. Sin embargo, debido a que A. lilljeborgii produce huevos diapáusicos o de reposo, que pueden ser transportados fuera o dentro de éstos cuerpos de agua, es probable que esta condición mantenga las frecuencias alélicas y genotípicas similares o muy cercanas entre sí. Los resultados mostraron la existencia de flujo genético, dado a través de una dispersión pasiva de los huevos diapáusicos que produce esta especie.

  12. Temporal and ephemeral variations in copepod community in the estuaries of Mandovi and Zuari - west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.; Goswami, S.C.

    In the tidal-dominated coastal plain estuaries, the magnitude of temporal and ephemeral variations in the abundance of the calonoid copepod community was evaluated over two annual cycles by two-way ANOVA. The species by species matrices were...

  13. Laboratory scale photobioreactor for high production of microalgae Rhodomonas salina used as food for intensive copepod cultures

    DEFF Research Database (Denmark)

    Thuy, Minh Vu Thi; Jepsen, Per Meyer; Hansen, Benni Winding

    Introduction Microalgae are essential feeds for many cultured molluscs, larvae of marine fishes, crustaceans as well as other important live feeds including rotifers, Artemia and copepods (Muller-Feuga, 2000). Microalgae are grown either in open culture systems (ponds) or closed systems...... (photobioreactor - PBR). There is an increasing interest in using closed PBRs for algae cultivation since this culture system provides a better control of cultivation conditions and enables higher algae productivity. Among the marine microalgae, the cryptophyte Rhodomonas salina is one of the optimal feed...... for copepods (Støttrup and Jensen, 1990; Zhang et al., 2013). Despite the benefit of using R. salina in cultivation of copepods, to our knowledge, there is no report on the production of this microalga at industrial scale to supply sufficient food for mass production of copepods. We intend to conduct the basic...

  14. Trophic Cascading of Medusae on the Relationships between Copepods and Diatoms in a Subtropical Coastal Ecosystem

    Directory of Open Access Journals (Sweden)

    Jia-Lu Chung

    2009-01-01

    Full Text Available To investigate the spatial and temporal variation of phytoplankton and copepods, eight seasonal cruises (January 2005 ~ Oc to ber 2006 were conducted in a subtropical coast site that encom passed 19 sampling stations. The results in dicated that the temperature (18.4 - 29.7°C varied more than 10°C seasonally, while nutrient concentrations (ni trate: 0.4 - 6.3 mM, phosphate: 0.1 - 0.8 mM, and silicate 2.1 - 12.1 mM were in versely corre lated with temperature. Diatoms (2792 - 1602437 cells m-3 constituted > 90% of the phytoplankton as semblages and dinoflagellates (226 - 10029 cells m-3 represented only ~10% of the algaebiomass. Copepod abun dance (8 - 1031 ind. m-3 varied positively with that of diatom and tempeature. Therelative abundance of Temora spp. (1 - 712 ind. m-3 varied from 69% in summer; that of Paracalanus spp. (0.1 - 176 ind. m-3 were > 25% in spring and au tumn and Calanus spp. (0.5 - 24 ind. m-3 dom i nated in win ter and spring, but ac counted for only ~10% of the to tal copepods. Both di a tom den sity and copepod abun dance were positively correlated with temperature, indicating these two plank tongroups were left bot tom-up control. The copepod abun dance positively co-aried with diatoms in 2005, but not in 2006. Fur ther sea son-to-sea son analysis showed that the diatomvs. copepodratios changed positively only when the medusa abun dance changed greatly (> 40-fold between consecutive sea sons. During periods when the medusa abundance varied less than 10-fold between seasons, there is no relationship between the ratios and the medusa abun dance. This study suggests that the stability of the medusa abundance from season to season could be important in regulating the ecological linkage between diatoms and their predators ¡V copepods.

  15. Copepod omnivory in the North Water Polynya (Baffin Bay) during autumn: spatial patterns in lipid composition

    Science.gov (United States)

    Stevens, Catherine J.; Deibel, Don; Parrish, Christopher C.

    2004-11-01

    To deduce spatial patterns in copepod lipid composition and feeding strategy (i.e., degree of omnivory) in the North Water Polynya (Baffin Bay), three dominant species were sampled extensively over a broad geographical area (∼75-78°N; 77-69°W). Calanus hyperboreus CV, C. glacialis CV and Metridia longa females were collected in shallow and deep strata at 16 stations during autumn 1999 (August-October). Principal components analysis (PCA) revealed that all species fed omnivorously in the southeastern (SE) region of the polynya. Here, copepods generally had elevated levels of carnivorous (e.g., 18 : 1 (n - 9)), dinoflagellate (e.g., 18 : 4 (n - 3) ; 22 : 6 (n - 3)) and bacterial fatty acid markers (e.g., odd-numbered and/or branched; 18:1(n - 7)). Copepods in the SE contained low proportions of diatom (e.g., 16 : 4 (n - 1) ; 20 : 5 (n - 3)) and phytoplankton (e.g., polyunsaturated fatty acids) markers, relative to animals from northwest stations. Values of the omnivory index 'UC' (i.e., unsaturation coefficient) were also low in SE copepods, which implied reduced phytoplankton ingestion. Spatial patterns in seston fatty acid composition resembled the dietary signatures in that dinoflagellate and bacterial indices were highest in SE waters. Estimates of primary production, particulate organic carbon, carbon to chlorophyll ratios, and abundances of diatoms, dinoflagellates and bacteria, provided further evidence of the importance of the microbial loop at SE stations. Comparable spatial patterns in feeding strategy were observed in both sampling layers, indicating that copepods from the entire water column were feeding on a similar food source. Several interesting species-specific trends also emerged from the PCA. In general, C. hyperboreus fed the most herbivorously, followed by C. glacialis and M. longa. C. glacialis showed a stronger connection to the microbial food web than the other two species, and M. longa fed herbivorously throughout much of the polynya

  16. RNA-seq based whole transcriptome analysis of the cyclopoid copepod Paracyclopina nana focusing on xenobiotics metabolism.

    Science.gov (United States)

    Lee, Bo-Young; Kim, Hui-Su; Choi, Beom-Soon; Hwang, Dae-Sik; Choi, Ah Young; Han, Jeonghoon; Won, Eun-Ji; Choi, Ik-Young; Lee, Seung-Hwi; Om, Ae-Son; Park, Heum Gi; Lee, Jae-Seong

    2015-09-01

    Copepods are among the most abundant taxa in marine invertebrates, and cyclopoid copepods include more than 1500 species and subspecies. In marine ecosystems, planktonic copepods play a significant role as food resources in the food web and sensitively respond to environmental changes. The copepod Paracylopina nana is one of the planktonic brackish water copepods and considered as a promising model species in ecotoxicology. We sequenced the whole transcriptome of P. nana using RNA-seq technology. De novo sequence assembly by Trinity integrated with TransDecoder produced 67,179 contigs including putative alternative spliced variants. A total of 12,474 genes were identified based on BLAST analysis, and gene sequences were most similar to the sequences of the branchiopod Daphnia. Gene Ontology and KEGG pathway analysis showed that most transcripts annotated were involved in pathways of various metabolisms, immune system, signal transduction, and translation. Considering numbers of sequences and enzymes involved in the pathways, particularly attention was paid to genes potentially involved in xenobiotics biodegradation and metabolism. With regard to xenobiotics metabolism, various xenobiotic metabolizing enzymes such as oxidases, dehydrogenases, and transferases were obtained from the annotated transcripts. The whole transcriptome analysis of P. nana provides valuable resources for future studies of xenobiotics-related metabolism in this marine copepod species.

  17. [Biological process of phosphorus turnover in surface water body of Xiamen Harbor. II: Grazing pressure of copepod on phytoplankton].

    Science.gov (United States)

    Yang, Wei-di; Yang, Qing; Lin, Yuan-shao; Cao, Wen-qing

    2008-12-01

    To understand the roles of copepod in the biogeochemical cycling of phosphorus, gut fluorescence method was applied to examine in situ the grazing rate of copepod on the phytoplankton in Xiamen Time Station (XMTS) in May, August and November 2005 and March 2006. In the meanwhile, the abundance and species composition of copepod were investigated, and the grazing pressure of copepod on the phytoplankton was estimated. The results showed that the annual average grazing rate of copepod was 55.53 microg x m(-3) x d(-1), being the highest (108.98 microg x m(-3) x d(-1)) in autumn and the lowest (7.18 microg x m(-3) x d(-1)) in summer. Based on the estimation from our experimental data, the daily grazing rate of copepod populations on the phytoplankton in Xiamen Harbor was, on annual average, about 1.81% of the phytoplankton's standing stock, with the values in spring, summer, autumn, and winter being 3.22%, 0.06%, 3.52% and 0.46%, respectively.

  18. Planktivorous feeding in calm and turbulent environments, with emphasis on copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, E.

    1995-01-01

    feeding copepods, such as Acartidae and many cyclopoids, turbulence has a dominant influence on prey encounter rates. The effect on cruising predators is intermediate. Application of the models to situations examined experimentally demonstrates a high predictive performance. Finally we explore and model...... the potentially negative effects of turbulence on copepod feeding currents, prey perception and capture success. At typical and even high turbulent intensities, none of these is significantly affected....... the levels of turbulence (as dissipation rate) at which ambient fluid motion is important in enhancing prey encounter rates for various types of predators (e.g, ambush and cruise predators, suspension feeders). Generally, turbulence has the largest effect on prey encounters for predators with low motility...

  19. Mating success and sexual selection in a pelagic copepod, Temora longicornis: Evidence from paternity analyses

    DEFF Research Database (Denmark)

    Sichlau, Mie Hylstofte; Eg Nielsen, Einar; Thygesen, Uffe Høgsbro;

    2015-01-01

    Knowledge about mating patterns is essential for understanding and explaining rates of reproduction and genetic potential of copepods populations. The aim of this study was to examine (1) the occurrence of multiple paternity in Temora longicornis, (2) the effect of multiple paternity (if present......) on the females reproductive output, and (3) whether mating is random or some individuals have a higher than average chance of fertilizing or being fertilized (super individuals). We show that multiple paternity is common in this copepod species, that females benefit from multiple matings by increased offspring...... production, and that a relatively small fraction of the males and females in a population account for most of the offspring production. In both males and females, mating is nonrandom. Superior individuals with a higher than average matings success were identified both among females and among males....

  20. Predator-prey interactions and community structure: chironomids, mosquitoes and copepods in Heliconia imbricata (Musaceae).

    Science.gov (United States)

    Naeem, Shahid

    1988-11-01

    Evidence from both field observations and experimental work indicates that predation by larvae of a midge, Pentaneura n. sp. (Chironomidae), causes the low densities of mosquito larvae (Culicidae) found in the water filled bracts of Heliconia imbricata (Musaceae), microhabitats typically colonized by mosquitoes. This predation affects 2 species of mosquitoes, Wyeomyia pseudopecten, a resident species, and Trichoprosopon digitatum, a non-resident species. Predation keeps resident mosquito densities low while completely excluding the nonresident mosquito from the habitat. Both these effects of predation depend on the presence of an abundant alternative prey, an undescribed species of harpacticoid copepod found in the bracts. These copepod prey sustain chironomids when resident mosquito densities are low, permiting predator densities to remain high enough to exclude the non-resident mosquito. I discuss the evolutionary and ecological implications of predation structuring communities.

  1. Unsteady motion: escape jumps in planktonic copepods, their kinematics and energetics

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Andersen, Anders Peter; Langlois, Vincent J.;

    2010-01-01

    estimate the force and power output needed to accelerate and overcome drag. Both are very high compared with those of other organisms, as are the escape velocities in comparison to startle velocities of other aquatic animals. Thus, the maximum weight-specific force, which for muscle motors of other animals...... has been found to be near constant at 57 N (kg muscle)−1, is more than an order of magnitude higher for the escaping copepods. We argue that this is feasible because most copepods have different systems for steady propulsion (feeding appendages) and intensive escapes (swimming legs), with the muscular...... arrangement of the latter probably adapted for high force production during short-lasting bursts. The resulting escape velocities scale with body length to power 0.65, different from the size-scaling of both similar sized and larger animals moving at constant velocity, but similar to that found for startle...

  2. Zooplankton distribution across Fram Strait in autumn: Are small copepods and protozooplankton important?

    Science.gov (United States)

    Svensen, Camilla; Seuthe, Lena; Vasilyeva, Yulia; Pasternak, Anna; Hansen, Edmond

    2011-12-01

    We investigated zooplankton distribution in September 2006/2007 at eight stations across Fram Strait in contrasting water masses ranging from cold Polar water to warm Atlantic water. Our main objectives were: (1) to describe the plankton community in the upper 200 m during autumn, and (2) to investigate the importance of small-sized copepods and protozooplankton in an arctic ecosystem when the majority of the large Calanus species had entered diapause. We sampled both with a WP-2 net and Go-Flo bottle and show that small copepods food. Heterotrophic protozooplankton, on the other hand, were most likely bottom-up regulated by the availability of phytoplankton food and conclude that there was a strong link between the zooplankton community and the microbial food web in Fram Strait.

  3. Influence of Kuroshio water on the annual copepod community structure in an estuary in the northwest Pacific Ocean

    Science.gov (United States)

    Tseng, Li-Chun; Hsiao, Shih-Hui; Sarkar, Santosh Kumar; Bhattacharya, Bhaskar Deb; Chen, Qing-Chao; Hwang, Jiang-Shiou

    2016-04-01

    The influence of Kuroshio water on temporal distribution and copepod diversity was investigated in the Lanyang River estuary (LRE), the longest river in northeast Taiwan, to assess secondary productivity. Zooplankton samples were collected bimonthly from the surface waters (0-2 m) of the estuary during cruises in 2006. Hydrological parameters indicated that the water in the LRE was an admixture of the Lanyang River water and seawater. Among the different genera, 47 copepod species (including 10 species that were identified only to the generic level) belonging to 28 genera, 16 families, and 4 orders were identified. The abundance and proportion of copepods to the total zooplankton counts range from 0 to 3683.42 (304.9±692.7 individuals m-3) and from 0 to 100 (55.09±34.84%) respectively. The copepod community structure revealed a distinct seasonal succession and showed significant differences among the sampling cruises (pANOVA). The 5 most abundant species were Parvocalanus crassirostris (relative abundance [RA]: 50.93%), Pseudodiaptomus serricaudatus (RA: 16.85%), Euterpina acutifrons (RA: 7.34%), Cyclops vicinus (RA: 4.82%), and Microcyclops tricolor (RA: 3.15%). The abundance, species number, indices of richness, evenness, and copepod diversity varied significantly (pANOVA) for all the cruises. Pearson correlation analysis results demonstrated that salinity was positively correlated with the copepod species number (r=0.637), total copepod abundance (r=0.456), and Shannon-Wiener diversity index (r=0.375) with a 1% level of significance. By contrast, the evenness index was negatively correlated with salinity (r=-0.375, p=0.01), indicating that copepod diversity in the LRE was influenced mainly by seawater. The Kuroshio Current played a major role in transporting and distributing warm-water copepods to its affected area. Copepod species assemblages showed seasonal succession and varied drastically with tidal change. The latter registered high abundance, and the

  4. Heritability of Sex Tendency in a Harpacticoid Copepod, Tigriopus californicus

    OpenAIRE

    Voordouw, Maarten J; Anholt, Bradley R.

    2011-01-01

    Systems with genetic variation for the primary sex ratio are important for testing sex-ratio theory and for understanding how this variation is maintained. Evidence is presented for heritable variation of the primary sex ratio in the harpacticoid copepod Tigriopus californicus. Variation in the primary sex ratio among families cannot be accounted for by Mendelian segregation of sex chromosomes. The covariance in sex phenotype between full-sibling clutches and between mothers and offspring sug...

  5. The Genetic Basis of Local Adaptation to Thermal Stress in the Intertidal Copepod Tigriopus Californicus /

    OpenAIRE

    Sefton, Margaret Marie

    2013-01-01

    Populations of the intertidal copepod, Tigriopus californicus, vary in their tolerance to thermal stress. In this study, the genetic basis of these differences was examined by generating interpopulation hybrids between a northern and southern population; hybrids were then exposed them to multiple generations of heat stress. At each generation, changes in allele frequency of six candidate genes were monitored. Although allelic frequencies did not change in response to thermal stress, there was...

  6. Recombination in interpopulation hybrids of the copepod Tigriopus californicus: release of beneficial variation despite hybrid breakdown.

    Science.gov (United States)

    Edmands, Suzanne

    2008-01-01

    Crosses between divergent populations of the copepod Tigriopus californicus typically result in fitness reductions for both F2 and backcross hybrids. Because females in this species lack chiasmatic meiosis, both recombinant and nonrecombinant backcross hybrids can be created. Recombinant hybrids were found to have significantly faster development time for both males and females in 2 pairs of crosses, indicating the creation of favorable gene combinations by disrupting parental linkage groups.

  7. Evolutionary genetics of hybrid breakdown in the marine copepod Tigriopus californicus

    OpenAIRE

    Ellison, Christopher K

    2008-01-01

    Populations of the supra-littoral marine copepod Tigriopus californicus are known to be highly divergent and to exhibit a pattern of hybrid breakdown when crossed under laboratory conditions. This dissertation examines the genetic mechanisms involved in hybrid breakdown in T. californicus, particularly those involving integration of the nuclear and mitochondrial genomes. In Chapter I, I summarize some of the relevant literature concerning the importance of hybrid breakdown to evolutionary bio...

  8. A gene-based SNP resource and linkage map for the copepod Tigriopus californicus

    OpenAIRE

    Foley Brad R; Rose Colin G; Rundle Daniel E; Leong Wai; Moy Gary W; Burton Ronald S; Edmands Suzanne

    2011-01-01

    Abstract Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct...

  9. Foraging mode and prey size spectra of suspension-feeding copepods and other zooplankton

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2016-01-01

    Prey size spectra of suspension-feeding zooplankton may be predicted from foraging mode and a mechanistic understanding of prey perception and capture. I examine this for suspension-feeding copepods where 2 foraging modes can be distinguished: ambush feeding and active (i.e. cruising and feeding...... the prediction. I also make qualitative predictions of food size spectra in zooplankton with other prey perception mechanisms that accord with observations....

  10. Growth and production of the copepod community in the southern area of the Humboldt Current System

    Directory of Open Access Journals (Sweden)

    R. Escribano

    2015-02-01

    Full Text Available Zooplankton production is a critical issue for understanding marine ecosystem structure and dynamics, however, its time-space variations are mostly unknown in most systems. In this study, estimates of copepod growth and production (CP in the coastal upwelling and coastal transition zones off central-southern Chile (∼35–37° S were obtained from annual cycles during a 3 year time series (2004, 2005, and 2006 at a fixed shelf station and from spring–summer surveys during the same years. C-specific growth rates (g varied extensively among species and under variable environmental conditions; however, g values were not correlated to either near surface temperature or copepod size. Copepod biomass (CB and CP were higher within the coastal upwelling zone (−2 year−1 with a~mean annual P/B ratio of 2.7. We estimated that CP could consume up to 60% of the annual primary production (PP in the upwelling zone but most of the time is around 8%. Interannual changes in CB and CP values were associated with changes in the copepod community structure, the dominance of large-sized forms replaced by small-sized species from 2004 to 2006. This change was accompanied by more persistent and time extended upwelling during the same seasonal period. Extended upwelling may have caused large losses of CB from the upwelling zone due to an increase in offshore advection of coastal plankton. On a larger scale, these results suggest that climate-related impacts of increasing wind-driven upwelling in coastal upwelling systems may generate a negative trend in zooplankton biomass.

  11. Synopsis of lichomolgid copepods (Poecilostomatoida) associated with soft corals (Alcyonacea) in the tropical Indo-Pacific

    OpenAIRE

    Humes, A.G.

    1990-01-01

    A synopsis of the 97 species of lichomolgid copepods known to be associated with tropical IndoPacific shallow-water alcyonaceans is given (Madagascar, New Caledonia, Moluccas, Philippines, and Enewetak Atoll). One new genus and 29 new species are included, distributed among the lichomolgid genera Acanthomolgus (2 new species), Alcyonomolgus (1), Colobomolgus (2), Critomolgus (3), Doridicola (5), Paradoridicola (7), Paramolgus (8), and Telestacicola (1). The alcyonacean hosts, numbering more t...

  12. Role of dispersants of oil on copepods in high arctic areas

    DEFF Research Database (Denmark)

    Gustavson, Kim; Nørregaard, Rasmus Dyrmose; Møller, Eva Friis;

    2013-01-01

    The purpose of the project is to increase the knowledge on the effects of using dispersants on oil spills in high arctic areas: more precisely, to investigate accumulation in and effects on high arctic copepods. Such knowledge is crucial for performing a robust net environmental benefit analysis...... prior to making a decision as to whether or not dispersant may be allowed as an operational oil spill response in high arctic sea areas....

  13. Low fertilization rates in a pelagic copepod caused by sexual selection?

    DEFF Research Database (Denmark)

    Ceballos, Sara; Sichlau, Mie Hylstofte; Heuschele, Jan;

    2014-01-01

    random mating. Such low fertilization rates are normally related to environmental factors such as poor food or low densities, which we could not confirm in our experiment. Male density was negatively related to fertilization rate, and a large fraction of males did not mate in laboratory incubations. We...... therefore suggest that sexual selection, through mate choice or male–male competition could account for low fertilization rates of females in populations of pelagic copepods during some periods of the year...

  14. Deleterious epistatic interactions between electron transport system protein-coding loci in the copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S

    2006-07-01

    The nature of epistatic interactions between genes encoding interacting proteins in hybrid organisms can have important implications for the evolution of postzygotic reproductive isolation and speciation. At this point very little is known about the fitness differences caused by specific closely interacting but evolutionarily divergent proteins in hybrids between populations or species. The intertidal copepod Tigriopus californicus provides an excellent model in which to study such interactions because the species range includes numerous genetically divergent populations that are still capable of being crossed in the laboratory. Here, the effect on fitness due to the interactions of three complex III proteins of the electron transport system in F2 hybrid copepods resulting from crosses of a pair of divergent populations is examined. Significant deviations from Mendelian inheritance are observed for each of the three genes in F2 hybrid adults but not in nauplii (larvae). The two-way interactions between these genes also have a significant impact upon the viability of these hybrid copepods. Dominance appears to play an important role in mediating the interactions between these loci as deviations are caused by heterozygote/homozygote deleterious interactions. These results suggest that the fitness consequences of the interactions of these three complex III-associated genes could influence reproductive isolation in this system.

  15. Occurrence and distribution of copepods (Crustacea in the epipelagial off southern Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Frederico Campaner

    1985-01-01

    Full Text Available The copepods of plankton samples collected with a Bongo net of 0.333 mm mesh in 66 oceanographic stations of 4 transects off the States of Rio de Janeiro (RJ and Santa Catarina (SC in Nov./Dec. 75 and May 76 were qualitatively and quantitatively studied. An amount of 173 species was identified, of which Paivella naporai Wheeler, Xanthocalanus marlyae Campaner, and Corycaeus giesbrechti F. Dahl were taxonomically reviewed. Frequency and density of each species, and absolute and mean density of total copepods were determined for every station, as well as frequency of adult females and males, and young forms. Abundance was higher in the neritic than in the oceanic zone, the mean density being twice greater of the neritic zone of RJ than in that of SC and almost identical in the oceanic zone off both States except for SC in Nov./Dec. 75, where values were thrice greater than in RJ. These results were related to the distribution of water masses in the sampling areas. Copepod associations were determined for neritic and oceanic zones off the States of RJ and SC at both sampling seasons.

  16. Size-dependent effects of micro polystyrene particles in the marine copepod Tigriopus japonicus.

    Science.gov (United States)

    Lee, Kyun-Woo; Shim, Won Joon; Kwon, Oh Youn; Kang, Jung-Hoon

    2013-10-01

    We investigated the effects of three sizes of polystyrene (PS) microbeads (0.05, 0.5, and 6-μm diameter) on the survival, development, and fecundity of the copepod Tigriopus japonicus using acute and chronic toxicity tests. T. japonicus ingested and egested all three sizes of PS beads used and exhibited no selective feeding when phytoplankton were added. The copepods (nauplius and adult females) survived all sizes of PS beads and the various concentrations tested in the acute toxicity test for 96 h. In the two-generation chronic toxicity test, 0.05-μm PS beads at a concentration greater than 12.5 μg/mL caused the mortality of nauplii and copepodites in the F0 generation and even triggered mortality at a concentration of 1.25 μg/mL in the next generation. In the 0.5-μm PS bead treatment, despite there being no significant effect on the F0 generation, the highest concentration (25 μg/mL) induced a significant decrease in survival compared with the control population in the F1 generation. The 6-μm PS beads did not affect the survival of T. japonicus over two generations. The 0.5- and 6-μm PS beads caused a significant decrease in fecundity at all concentrations. These results suggest that microplastics such as micro- or nanosized PS beads may have negative impacts on marine copepods.

  17. First record of Neoergasilus japonicus (Poecilostomatoida: Ergasilidae), a parasitic copepod new to the Laurentian Great Lakes

    Science.gov (United States)

    Hudson, Patrick L.; Bowen, Charles A.

    2002-01-01

    The parasitic copepod Neoergasilus japonicus, native to eastern Asia, was first collected from 4 species of fish (fathead minnow, Pimephales promelas; largemouth bass, Micropterus salmoides; pumpkinseed sunfish, Lepomis gibbosus; and yellow perch, Perca flavescens) in July 1994 in Saginaw Bay, Lake Huron, Michigan. Further sampling in the bay in 2001 revealed infections on 7 additional species (bluegill, Lepomis macrochirus; carp, Cyprinus carpio; channel catfish, Ictalurus punctatus; goldfish, Carassius auratus; green sunfish, Lepomis cyanellus; rock bass, Ambloplites rupestris; and smallmouth bass, Micropterus dolomieu). An additional 21 species examined in 2001 were devoid of the parasite. A limited collection of fish from Lake Superior (n = 8) and Lake Michigan (n = 46) in 1994 showed no infection. Neoergasilus japonicus is most frequently found attached to the dorsal fin and, in decreasing frequency, on the anal, tail, pelvic, and pectoral fins. Prevalence generally ranged from 15 to 70 and intensity from 1 to 10. The greatest number of copepods on a single host was 44. The copepod Neoergasilus japonicus appears to disperse over long distances rather quickly, spreading across Europe in 20 yr and then moving on to North America over a span of 10 yr. Its main vehicle of transport and introduction into the Great Lakes is probably exotic fish hosts associated with the fish-culture industry.

  18. Transcriptome sequencing and de novo analysis of the copepod Calanus sinicus using 454 GS FLX.

    Directory of Open Access Journals (Sweden)

    Juan Ning

    Full Text Available BACKGROUND: Despite their species abundance and primary economic importance, genomic information about copepods is still limited. In particular, genomic resources are lacking for the copepod Calanus sinicus, which is a dominant species in the coastal waters of East Asia. In this study, we performed de novo transcriptome sequencing to produce a large number of expressed sequence tags for the copepod C. sinicus. RESULTS: Copepodid larvae and adults were used as the basic material for transcriptome sequencing. Using 454 pyrosequencing, a total of 1,470,799 reads were obtained, which were assembled into 56,809 high quality expressed sequence tags. Based on their sequence similarity to known proteins, about 14,000 different genes were identified, including members of all major conserved signaling pathways. Transcripts that were putatively involved with growth, lipid metabolism, molting, and diapause were also identified among these genes. Differentially expressed genes related to several processes were found in C. sinicus copepodid larvae and adults. We detected 284,154 single nucleotide polymorphisms (SNPs that provide a resource for gene function studies. CONCLUSION: Our data provide the most comprehensive transcriptome resource available for C. sinicus. This resource allowed us to identify genes associated with primary physiological processes and SNPs in coding regions, which facilitated the quantitative analysis of differential gene expression. These data should provide foundation for future genetic and genomic studies of this and related species.

  19. Identification and molecular characterization of nitric oxide synthase (NOS) gene in the intertidal copepod Tigriopus japonicus.

    Science.gov (United States)

    Jeong, Chang-Bum; Kang, Hye-Min; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2016-02-10

    In copepods, no information has been reported on the structure or molecular characterization of the nitric oxide synthase (NOS) gene. In the intertidal copepod Tigriopus japonicus, we identified a NOS gene that is involved in immune responses of vertebrates and invertebrates. In silico analyses revealed that nitric oxide (NO) synthase domains, such as the oxygenase and reductase domains, are highly conserved in the T. japonicus NOS gene. The T. japonicus NOS gene was highly transcribed in the nauplii stages, implying that it plays a role in protecting the host during the early developmental stages. To examine the involvement of the T. japonicus NOS gene in the innate immune response, the copepods were exposed to lipopolysaccharide (LPS) and two Vibrio sp. After exposure to different concentrations of LPS and Vibrio sp., T. japonicus NOS transcription was significantly increased over time in a dose-dependent manner, and the NO/nitrite concentration increased as well. Taken together, our findings suggest that T. japonicus NOS transcription is induced in response to an immune challenge as part of the conserved innate immunity.

  20. Interactions of Copepods with Fractal-Grid Generated Turbulence based on Tomo-PIV and 3D-PTV

    Science.gov (United States)

    Sun, Zhengzhong; Krizan, Daniel; Longmire, Ellen

    2014-11-01

    A copepod escapes from predation by sensing fluid motion caused by the predator. It is thought that the escape reaction is elicited by a threshold value of the maximum principal strain rate (MPSR) in the flow. The present experimental work attempts to investigate and quantify the MPSR threshold value. In the experiment, copepods interact with turbulence generated by a fractal grid in a recirculating channel. The turbulent flow is measured by time-resolved Tomo-PIV, while the copepod motion is tracked simultaneously through 3D-PTV. Escape reactions are detected based on copepod trajectories and velocity vectors, while the surrounding hydrodynamic information is retrieved from the corresponding location in the 3D instantaneous flow field. Measurements are performed at three locations downstream of the fractal grid, such that various turbulence levels can be achieved. Preliminary results show that the number of escape reactions decreases at locations with reduced turbulence levels, where shorter jump distances and smaller change of swimming orientation are exhibited. Detailed quantitative results of MPSR threshold values and the dynamics of copepod escape will be presented. Supported by NSF-IDBR Grant #0852875.

  1. Corallovexiidae, a new family of transformed copepods endoparasitic in reef corals with two new genera and ten new species from Curaçao

    NARCIS (Netherlands)

    Stock, Jan H.

    1975-01-01

    Quite a few endoparasitic copepods are known from Indo-Pacific stony corals, but not a single species has so far been recorded from the West Indies. Intensive search in the past few decades has even supported the prevailing opinion that West Indian stony corals are devoid of endoparasitic copepods,

  2. How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods

    DEFF Research Database (Denmark)

    Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

    2016-01-01

    defecation rates ranged from 5.3 to 245 ng-oil copepod(-1) d(-1), which represent a mean weight-specific defecation rate of 0.026 mu g-oil mu g-C-copepod(1) d(-1). Considering a dispersed crude oil concentration commonly found in the water column after oil spills (1 mu l L-1) and copepod abundances in high...... of oil spills in the short term, but may be quantitatively important in the flux of oil from surface water to sediments and in the transfer of low-solubility, toxic petroleum hydrocarbons into food webs after crude oil spills in the sea. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open...

  3. Non-limiting food conditions for growth and production of the copepod community in a highly productive upwelling zone

    Science.gov (United States)

    Escribano, Rubén; Bustos-Ríos, Evelyn; Hidalgo, Pamela; Morales, Carmen E.

    2016-09-01

    Zooplankton production is critical for understanding marine ecosystem dynamics. This work estimates copepod growth and production in the coastal upwelling and coastal transition zones off central-southern Chile (~35 to 37°S) during a 3-year time series (2004, 2005, and 2006) at a fixed shelf station, and from spring-summer spatial surveys during the same period. To estimate copepod production (CP), we used species-biomasses and associated C-specific growth rates from temperature dependent equations (food-saturated) for the dominant species, which we assumed were maximal growth rates (gmax). Using chlorophyll-a concentrations as a proxy for food conditions, we determined a size-dependent half-saturation constant with the Michaelis-Menten equation to derive growth rates (g) under the effect of food limitation. These food-dependent C-specific growth rates were much lower (absence of bottom-up control, allowing copepods to grow without limitation due to food resources.

  4. Seasonality of parasitic copepods on bullseye puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), from the northwestern coast of Mexico.

    Science.gov (United States)

    Morales-Serna, Francisco Neptalí; Rubio-Godoy, Miguel; Gómez, Samuel

    2011-08-01

    Seasonal occurrence of parasitic copepods in wild bullseye puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), was analyzed in conjunction with variation of biotic and abiotic factors. Eleven samples were taken between February 2007 and February 2008 in Santa María La Reforma lagoon (northwestern coast of México). In total, 337 fish was examined; 5 parasitic copepod species were observed, including Acantholochus zairae , Caligus serratus , Lepeophtheirus simplex , Pseudochondracanthus diceraus , and Parabrachiella sp. The most common species were L. simplex , P. diceraus, and C. serratus (overall prevalence, 59, 53, and 35%, respectively), which significantly varied in prevalence and mean intensity between sampling months. A seasonal pattern was only observed for L. simplex, with higher infection levels in the warmest month than in the coldest month. Statistical analyses indicated that the intensity of L. simplex was positively correlated with water temperature. There were no significant differences in prevalence and intensity of infection among female and male hosts. At the component community level, species richness ranged between 4 and 5 during most of the study period, and no seasonality was observed in the number of individuals, Shannon diversity index, evenness index, or the Berger-Parker dominance index. At the infracommunity level, 4 descriptors used (mean species richness, mean number of individuals, mean Brillouin's diversity index, and mean Berger-Parker index) varied significantly between sampling months, but no seasonality was observed, except for a slight increase in the number of individuals during the warmest month. A significant positive association was detected between number of individuals and water temperature and between host size and both species richness and number of individuals. This is the first account of the ecology of these 5 parasitic copepods. Although no significant association was detected between fish condition factor and the

  5. Exploring copepod distribution patterns at three nested spatial scales in a spring system: habitat partitioning and potential for hydrological bioindication

    Directory of Open Access Journals (Sweden)

    Fabio Stoch

    2015-06-01

    Full Text Available In groundwater-fed springs, habitat characteristics are primarily determined by a complex combination of geomorphic features and physico-chemical parameters, while species assemblages are even more intricate. Springs host species either inhabiting the spring mouth, or colonizing spring habitats from the surface or from the aquifers which feed the springs. Groundwater species living in springs have been claimed as good candidates for identifying dual aquifer flowpaths or changes in groundwater pathways before reaching the spring outlets. However, the reliability of spring species as hydrological biotracers has not been widely investigated so far. Our study was aimed at analysing a large karstic spring system at three nested spatial scales in order: i to assess, at whole spring system scale, the presence of a groundwater divide separating two aquifers feeding two spring units within a single spring system, by combining isotope analyses, physico-chemistry, and copepod distribution patterns; ii to test, at vertical spring system scale, the effectiveness of copepods in discriminating surface and subsurface habitat patches within the complex mosaic spring environment; iii to explore, at local spring unit level, the relative role of hydrochemistry and sediment texture as describers of copepod distribution among microhabitats. The results obtained demonstrated the presence of a hierarchical spatial structure, interestingly reflected in significant differences in assemblage compositions. Copepod assemblages differed between the two contiguous spring units, which were clearly characterized by their hydrochemistry and by significant differences in the groundwater flowpaths and recharge areas, as derived by the isotope analyses. The biological results suggested that stygobiotic species seem to be related to the origin of groundwater, suggesting their potential role as hydrological biotracers. At vertical scale, assemblage composition in surface and

  6. Temperature Affects the Use of Storage Fatty Acids as Energy Source in a Benthic Copepod (Platychelipus littoralis, Harpacticoida).

    Science.gov (United States)

    Werbrouck, Eva; Van Gansbeke, Dirk; Vanreusel, Ann; De Troch, Marleen

    2016-01-01

    The utilization of storage lipids and their associated fatty acids (FA) is an important means for organisms to cope with periods of food shortage, however, little is known about the dynamics and FA mobilization in benthic copepods (order Harpacticoida). Furthermore, lipid depletion and FA mobilization may depend on the ambient temperature. Therefore, we subjected the temperate copepod Platychelipus littoralis to several intervals (3, 6 and 14 days) of food deprivation, under two temperatures in the range of the normal habitat temperature (4, 15 °C) and under an elevated temperature (24 °C), and studied the changes in FA composition of storage and membrane lipids. Although bulk depletion of storage FA occurred after a few days of food deprivation under 4 °C and 15 °C, copepod survival remained high during the experiment, suggesting the catabolization of other energy sources. Ambient temperature affected both the degree of FA depletion and the FA mobilization. In particular, storage FA were more exhausted and FA mobilization was more selective under 15 °C compared with 4 °C. In contrast, depletion of storage FA was limited under an elevated temperature, potentially due to a switch to partial anaerobiosis. Food deprivation induced selective DHA retention in the copepod's membrane, under all temperatures. However, prolonged exposure to heat and nutritional stress eventually depleted DHA in the membranes, and potentially induced high copepod mortality. Storage lipids clearly played an important role in the short-term response of the copepod P. littoralis to food deprivation. However, under elevated temperature, the use of storage FA as an energy source is compromised.

  7. Early ice retreat and ocean warming may induce copepod biogeographic boundary shifts in the Arctic Ocean

    Science.gov (United States)

    Feng, Zhixuan; Ji, Rubao; Campbell, Robert G.; Ashjian, Carin J.; Zhang, Jinlun

    2016-08-01

    Early ice retreat and ocean warming are changing various facets of the Arctic marine ecosystem, including the biogeographic distribution of marine organisms. Here an endemic copepod species, Calanus glacialis, was used as a model organism, to understand how and why Arctic marine environmental changes may induce biogeographic boundary shifts. A copepod individual-based model was coupled to an ice-ocean-ecosystem model to simulate temperature- and food-dependent copepod life history development. Numerical experiments were conducted for two contrasting years: a relatively cold and normal sea ice year (2001) and a well-known warm year with early ice retreat (2007). Model results agreed with commonly known biogeographic distributions of C. glacialis, which is a shelf/slope species and cannot colonize the vast majority of the central Arctic basins. Individuals along the northern boundaries of this species' distribution were most susceptible to reproduction timing and early food availability (released sea ice algae). In the Beaufort, Chukchi, East Siberian, and Laptev Seas where severe ocean warming and loss of sea ice occurred in summer 2007, relatively early ice retreat, elevated ocean temperature (about 1-2°C higher than 2001), increased phytoplankton food, and prolonged growth season created favorable conditions for C. glacialis development and caused a remarkable poleward expansion of its distribution. From a pan-Arctic perspective, despite the great heterogeneity in the temperature and food regimes, common biogeographic zones were identified from model simulations, thus allowing a better characterization of habitats and prediction of potential future biogeographic boundary shifts.

  8. Use of flubendazole as a therapeutic agent against rotifers (Brachionus plicatilis) in intensive cultures of the harpacticoid copepod Tisbe holothuriae

    DEFF Research Database (Denmark)

    Steenfeldt, Svend Jørgen; Nielsen, Johan W.

    2010-01-01

    holothuria). Flubendazole was lethal to rotifers in concentrations as low as 0.05 mg L−1. There was no significant effect on the concentration of copepods, even at the highest concentration tested, i.e. 5.0 mg L−1 flubendazole. We conclude that flubendazole is an effective drug for control of B. plicatilis...... down production and subsequently use a therapeutic agent to eliminate all zooplankton in the system before restart with a stock culture free of rotifers. We tested flubendazole as a mean of controlling rotifers (Brachionus plicatilis) in intensive laboratory cultures of the harpacticoid copepod (Tisbe...

  9. Potential of the small cyclopoid copepod Paracyclopina nana as an invertebrate model for ecotoxicity testing.

    Science.gov (United States)

    Dahms, Hans-Uwe; Won, Eun-Ji; Kim, Hui-Su; Han, Jeonghoon; Park, Heum Gi; Souissi, Sami; Raisuddin, Sheikh; Lee, Jae-Seong

    2016-11-01

    Aquatic invertebrates contribute significantly to environmental impact assessment of contaminants in aquatic ecosystems. Much effort has been made to identify viable and ecologically relevant invertebrate test organisms to meet rigorous regulatory requirements. Copepods, which are ecologically important and widely distributed in aquatic organisms, offer a huge opportunity as test organisms for aquatic toxicity testing. They have a major role not only in the transfer of energy in aquatic food chains, but also as a medium of transfer of aquatic pollutants across the tropic levels. In this regard, a supratidal and benthic harpacticoid copepod Tigriopus japonicus Mori (order Harpacticoida) has shown promising characteristics as a test organism in the field of ecotoxicology. Because there is a need to standardize a battery of test organisms from species in different phylogenetic and critical ecosystem positions, it is important to identify another unrelated planktonic species for wider application and comparison. In this regard, the cyclopoid copepod Paracyclopina nana Smirnov (order Cyclopoida) has emerged as a potential test organism to meet such requirements. Like T. japonicus, it has a number of features that make it a candidate worth consideration in such efforts. Recently, the genomics of P. nana has been unraveled. Data on biochemical and molecular responses of P. nana against exposure to environmental chemicals and other stressors have been collected. Recently, sequences and expression profiles of a number of genes in P. nana encoding for heat shock proteins, xenobiotic-metabolizing enzymes, and antioxidants have been reported. These genes serve as potential biomarkers in biomonitoring of environmental pollutants. Moreover, the application of gene expression techniques and the use of its whole transcriptome have allowed evaluation of transcriptional changes in P. nana with the ultimate aim of understanding the mechanisms of action of environmental stressors

  10. Effect of chemically contaminated marine sediment on naupliar production of the marine harpacticoid copepod, Tigriopus californicus

    Energy Technology Data Exchange (ETDEWEB)

    Misitano, D.A.; Schiewe, M.H. (National Oceanic and Atmospheric Administration, Seattle, WA (USA))

    1990-04-01

    There is a growing body of evidence indicating that chemically contaminated sediments in urban bays and estuaries pose a significant threat to the productivity of these important marine habitats. Particularly at risk are benthic species which live in direct contact with the sediment. However, nondemersal species are also at risk via the food chain and by direct contact with resuspended sediment particulates. There are substantial data on the lethal and sublethal effects of aqueous contaminants on a variety of aquatic species. In contrast, there is very limited information on the toxic effects of the generally water-insoluble sediment-associated contaminants. In the present communication the authors report a series of experiments in which the harpacticoid copepod, Tigriopus californicus, was exposed to sediments from urban and nonurban bays, and reproductive success was evaluated. This species was selected for study as it is widely distributed along the West Coast of North America, and as a group, copepods are an important component of the marine food chain. In addition, the relatively short reproductive life span of this species makes it particularly amenable for studies of reproductive success. Here, the authors report reduced and irregular naupliar production as a consequence of exposure to chemically contaminated sediments from urban waterways.

  11. Potential fitness trade-offs for thermal tolerance in the intertidal copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S

    2010-09-01

    Thermal adaptation to spatially varying environmental conditions occurs in a wide range of species, but what is less clear is the nature of fitness trade-offs associated with this temperature adaptation. Here, populations of the intertidal copepod Tigriopus californicus are examined at both local and latitudinal scales to determine whether these populations have evolved differences in their survival under high temperature stress. A clear pattern of increasing high temperature stress tolerance is seen with decreasing latitude, consistent with temperature adaptation. Additionally, there is also evidence for significant variation in thermal tolerance on a smaller scale. The competitive fitness of pairs of northern and southern copepod populations were also examined under a series of lower, more moderate temperatures. These fitness assays show that the southern populations that have the best survival under extreme high temperatures have lowered competitive fitness at the lower temperatures tested, whereas the fitness of the southern populations exceeded that of the northern populations at the highest temperatures tested. Combined, these results suggest that there may be evolutionary trade-offs between performance at high and stressful temperatures and fitness at moderate temperatures in this species.

  12. Interpopulational variation in the cold tolerance of a broadly distributed marine copepod.

    Science.gov (United States)

    Wallace, Gemma T; Kim, Tiffany L; Neufeld, Christopher J

    2014-01-01

    Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change.

  13. Hybrid breakdown weakens under thermal stress in population crosses of the copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S

    2012-01-01

    The outcome of hybridization can be impacted by environmental conditions, which themselves can contribute to reproductive isolation between taxa. In crosses of genetically divergent populations, hybridization can have both negative and positive impacts on fitness, the balance between which might be tipped by changes in the environment. Genetically divergent populations of the intertidal copepod Tigriopus californicus have been shown to differ in thermal tolerance at high temperatures along a latitudinal gradient. In this study, a series of crosses were made between pairs of genetically divergent populations of T. californicus, and the thermal tolerance of these hybrids was tested. In most cases, the first-generation hybrids had relatively high thermal tolerance and the second-generation hybrids were not generally reduced below the less-tolerant parental population for high temperature tolerance. This pattern contrasts with previous studies from crosses of genetically divergent populations of this copepod, which often shows hybrid breakdown in these second-generation hybrids for other measures of fitness. These results suggest that high temperature stress could either increase the positive impacts of hybridization or decrease the negative impacts of hybridization resulting in lowered hybrid breakdown in these population crosses.

  14. Characterization of the glutamate dehydrogenase gene and its regulation in a euryhaline copepod.

    Science.gov (United States)

    Willett, Christopher S; Burton, Ronald S

    2003-08-01

    Glutamate dehydrogenase (GDH) plays a key role in the metabolism of free amino acids (FAA) in crustaceans and other metazoans. Glutamate synthesized by GDH via reductive amination is the amino group donor for alanine synthesis and the precursor required for proline synthesis. Since both proline and alanine are important intracellular osmolytes in many marine invertebrates, GDH has been widely implicated as playing a central role in response to hyperosmotic stress in these organisms. We have isolated the gene encoding a GDH homolog from the euryhaline copepod Tigriopus californicus and examined the regulation of GDH under salinity stress. The gene encodes a protein of 557 residues with 76% amino acid identity with Drosophila melanogaster GDH. The gene encodes an N-terminal mitochondrial signal sequence peptide. Only a single intron of 71 bp was found in the GDH gene in T. californicus when genomic sequences and cDNA sequences were compared. The levels of GDH mRNA do not increase during hyperosmotic stress in this copepod. The effects of salt and hyperosmotic stress on GDH enzyme activity were also investigated. GDH activities decrease with increasing NaCl concentrations in in vitro enzyme assays, while live animals exposed to hyperosmotic stress showed no change in GDH enzyme activities. Combined, these results indicate that GDH transcription and enzyme activity do not appear to function in the regulation of alanine and proline accumulation during hyperosmotic stress in T. californicus. The manner in which this important physiological process is regulated remains unknown.

  15. The nature of interactions that contribute to postzygotic reproductive isolation in hybrid copepods.

    Science.gov (United States)

    Willett, Christopher S

    2011-05-01

    Deleterious interactions within the genome of hybrids can lower fitness and result in postzygotic reproductive isolation. Understanding the genetic basis of these deleterious interactions, known as Dobzhansky-Muller incompatibilities, is the subject of intense current study that seeks to elucidate the nature of these deleterious interactions. Hybrids from crosses of individuals from genetically divergent populations of the intertidal copepod Tigriopus californicus provide a useful model in which to study Dobzhansky-Muller incompatibilities. Studies of the basis of postzygotic reproductive isolation in this species have revealed a number of patterns. First, there is evidence for a breakdown in genomic coadaptation between mtDNA-encoded and nuclear-encoded proteins that can result in a reduction in hybrid fitness in some crosses. It appears from studies of the individual genes involved in these interactions that although this coadaptation could lead to asymmetries between crosses, patterns of genotypic viabilities are not often consistent with simple models of genomic coadaptation. Second, there is a large impact of environmental factors on these deleterious interactions suggesting that they are not strictly intrinsic in nature. Temperature in particular appears to play an important role in determining the nature of these interactions. Finally, deleterious interactions in these hybrid copepods appear to be complex in terms of the number of genetic factors that interact to lead to reductions in hybrid fitness. This complexity may stem from three or more factors that all interact to cause a single incompatibility or the same factor interacting with multiple other factors independently leading to multiple incompatibilities.

  16. Optimal salinity for dominant copepods in the East China Sea, determined using a yield density model

    Institute of Scientific and Technical Information of China (English)

    XU Zhaoli; GAO Qian

    2011-01-01

    From 1997 to 2000, four field surveys were conducted in the East China Sea (ECS)(23°30′ 33°00′N, 118°30′-128°00′E). A field data yield density model was used to determine the optimal salinities for 19 dominant copepod species to establish the relationship between surface salinities and abundance of those species. In addition, ecological groups of the copepods were classified based on optimal salinity and geographical distribution. The results indicate that the yield density model is suitable for determining the relationship between salinity and abundance. Cosmocalanus darwini, Euchaeta rimana,Pleuromamma gracilis, Rhincalanus cornutus, Scolecithrix danae and Pareucalanus attenuatus were determined as oceanic species, with optimal salinities of >34.0. They were stenohaline and mainly distributed in waters influenced by the Kuroshio or Taiwan warm current. Temoa discaudata, T. stylifera and Canthocalanus pauper were nearshore species with optimal salinities of <33.0 and most abundant in coastal waters. The remaining 10 species, including Undinula vulgaris and Subeucalanus subcrassus, were offshore species, with optimal salinity ranging from 33.0-34.0. They were widely distributed in nearshore,offshore and oceanic waters but mainly in the mixed water of the ECS.

  17. Exposure to crude oil micro-droplets causes reduced food uptake in copepods associated with alteration in their metabolic profiles.

    Science.gov (United States)

    Hansen, Bjørn Henrik; Altin, Dag; Nordtug, Trond; Øverjordet, Ida Beathe; Olsen, Anders J; Krause, Dan; Størdal, Ingvild; Størseth, Trond R

    2017-03-01

    Acute oil spills and produced water discharges may cause exposure of filter-feeding pelagic organisms to micron-sized dispersed oil droplets. The dissolved oil components are expected to be the main driver for oil dispersion toxicity; however, very few studies have investigated the specific contribution of oil droplets to toxicity. In the present work, the contribution of oil micro-droplet toxicity in dispersions was isolated by comparing exposures to oil dispersions (water soluble fraction with droplets) to concurrent exposure to filtered dispersions (water-soluble fractions without droplets). Physical (coloration) and behavioral (feeding activity) as well as molecular (metabolite profiling) responses to oil exposures in the copepod Calanus finmarchicus were studied. At high dispersion concentrations (4.1-5.6mg oil/L), copepods displayed carapace discoloration and reduced swimming activity. Reduced feeding activity, measured as algae uptake, gut filling and fecal pellet production, was evident also for lower concentrations (0.08mg oil/L). Alterations in metabolic profiles were also observed following exposure to oil dispersions. The pattern of responses were similar between two comparable experiments with different oil types, suggesting responses to be non-oil type specific. Furthermore, oil micro-droplets appear to contribute to some of the observed effects triggering a starvation-type response, manifested as a reduction in metabolite (homarine, acetylcholine, creatine and lactate) concentrations in copepods. Our work clearly displays a relationship between crude oil micro-droplet exposure and reduced uptake of algae in copepods.

  18. Tolerance and genetic relatedness of three meiobenthic copepod populations exposed to sediment-associated contaminant mixtures: Role of environmental history

    Energy Technology Data Exchange (ETDEWEB)

    Kovatch, C.E.; Schizas, N.V.; Chandler, G.T.; Coull, B.C.; Quattro, J.M.

    2000-04-01

    Meiobenthic copepod populations (Microarthridion littoral) were collected from three South Carolina, USA, estuaries having different pollution stress histories (i.e., pristine sediments, high polycyclic aromatic hydrocarbon [PAH] sediments, high metals/moderate PAH sediments) and then assayed for survival and reproductive output in 14-d exposures to pristine and heavily PAH/metals-contaminated sediment mixture exhibited differential survival and reproductive outputs as a function of previous environmental histories and whether genetic relatedness among populations measured as DNA sequences of the mitochondrial gene, cytochrome apoenzyme b, were linked to copepod contaminant tolerance. Overall, adult survival and reproductive success in contaminated sediments were significantly reduced relative to controls for all three populations irrespective of environmental histories. Differential resistance to sediment-contaminant mixtures by the two copepod populations inhabiting the contaminated sites was not found, despite their previous exposures to mixed contaminants at {Sigma}PAH and {Sigma}Metal concentrations of 7,287 to 2,467 ng/g dry wt and 461 to 3,497 {micro}g/g, respectively. Significant genetic differentiation, however, was found between copepod populations from the control and the two contaminated sites. Generally, cross-population survival and reproductive outputs were not significantly different and could not be linked to genetic differentiation at the population level.

  19. The population dynamics of the parasitic copepode Lernaeocera lusci (Bassett-Smith, 1896) on its definitive host

    NARCIS (Netherlands)

    Van Damme, P.A.; Hamerlynck, O.; Ollevier, F.

    1996-01-01

    The mesoparasitic copepod Lernaeocera lusci (Bassett-Smith, 1896) was recovered from first-year bib (Trisopterus luscus L.) in the Voordelta (Southern Eight of the North Sea) from May until December 1989. Analysis of the seasonal abundance and of the population structure showed that transmission of

  20. Deterioration in the biodiversity of copepods in sewage laiden creeks of Mumbai coast, west coast of India: A statistical approach.

    Digital Repository Service at National Institute of Oceanography (India)

    Stephen, R.; Jayalakshmy, K.V.; Nair, V.R.; Gajbhiye, S.N.; Jacob, B.

    . The water quality has been reported to be deteriorating which may have adverse effect on the fauna especially zooplankton - the subtle community. Copepods contribute about 70-90% of the total zooplankton in the marine ecosystems. Major portion of the waste...

  1. Biology and infestation rate of Corallonoxia longicauda, an endoparasitic copepod of the West Indian reef coral Meandrina meandrites

    NARCIS (Netherlands)

    Butter, Maureen E.

    1979-01-01

    During 1½ year the biology of Corallonoxia longicauda, a copepod endoparasitic in the stony coral Meandrina meandrites was studied in Curaçao, Netherlands Antilles. The infestation rate of the corals as well as the numbers of parasites present were investigated at several depths and in several stati

  2. Effect of culture density and antioxidants on naupliar production and gene expression of the cyclopoid copepod, Paracyclopina nana.

    Science.gov (United States)

    Lee, Kyun-Woo; Rhee, Jae-Sung; Han, Jeonghoon; Park, Heum Gi; Lee, Jae-Seong

    2012-02-01

    Although attempts have been made to use mass cultures of marine copepods as live foods in marine aquaculture, some limitations such as low density culture still exist. The brackish water cyclopoid copepod, Paracyclopina nana has the potential for mass culturing as live food. In this study, we not only investigated the effect of culture density on the naupliar production and specific gene expressions of P. nana, but also the effect of several antioxidants under the conditions of a high density culture. The naupliar production of the copepod decreased with increasing culture density. The expression of glutathione reductase (GR), selenium-dependent glutathione peroxidase (SeGPx), glutathione S-transferase kappa (GST kappa), heat shock protein 40 (Hsp40), and Hsp70 genes of P. nana increased in the high density treatment but vitellogenin genes (Vg1 and Vg2) showed downregulation. In the condition with 20 inds./mL, vitamin C had a significant decrease but sodium selenite induced the naupliar production of P. nana greatly. The expressions of GR, SeGPx, Hsp70, and Vg genes increased with the vitamin C treatment. Sodium selenite caused a decrease of SeGPx and Hsp40 but GST kappa increased in the treatment with 20 inds./mL. These results suggest that sodium selenite is a positive antioxidant which can increase the culture efficiency of the copepod.

  3. Distinctly different behavioral responses of a copepod, Temora longicornis, to different strains of toxic dinoflagellates, Alexandrium spp

    DEFF Research Database (Denmark)

    Xu, Jiayi; Hansen, Per Juel; Nielsen, Lasse Tor;

    2017-01-01

    Zooplankton responses to toxic algae are highly variable, even towards taxonomically closely related species or different strains of the same species. Here, the individual level feeding behavior of a copepod, Temora longicornis, was examined which offered 4 similarly sized strains of toxic dinofl...

  4. The copepod Tigriopus: a promising marine model organism for ecotoxicology and environmental genomics.

    Science.gov (United States)

    Raisuddin, Sheikh; Kwok, Kevin W H; Leung, Kenneth M Y; Schlenk, Daniel; Lee, Jae-Seong

    2007-07-20

    There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in such efforts. Tigriopus and other copepods are widely distributed and ecologically important organisms. Their position in marine food chains is very prominent, especially with regard to the transfer of energy. Copepods also play an important role in the transportation of aquatic pollutants across the food chains. In recent years there has been a phenomenal increase in the knowledge base of Tigriopus spp., particularly in the areas of their ecology, geophylogeny, genomics and their behavioural, biochemical and molecular responses following exposure to environmental stressors and chemicals. Sequences of a number of important marker genes have been studied in various Tigriopus spp., notably T. californicus and T. japonicus. These genes belong to normal biophysiological functions (e.g. electron transport system enzymes) as well as stress and toxic chemical exposure responses (heat shock protein 20, glutathione reductase, glutathione S-transferase). Recently, 40,740 expressed sequenced tags (ESTs) from T. japonicus, have been sequenced and of them, 5,673 ESTs showed significant hits (E-value, >1.0E-05) to the red flour beetle Tribolium genome database. Metals and organic pollutants such as antifouling agents, pesticides, polycyclic aromatic hydrocarbons (PAH) and polychrlorinated biphenyls (PCB) have shown reproducible biological responses when tested in Tigriopus spp. Promising results have been obtained when Tigriopus was used for assessment of risk associated with exposure to endocrine-disrupting chemicals (EDCs). Application of environmental

  5. The copepod Tigriopus: A promising marine model organism for ecotoxicology and environmental genomics

    Energy Technology Data Exchange (ETDEWEB)

    Raisuddin, Sheikh [Department of Chemistry and the National Research Lab of Marine Molecular and Environmental Bioscience, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kwok, Kevin W.H. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China); Leung, Kenneth M.Y. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China); Schlenk, Daniel [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Lee, Jae-Seong [Department of Chemistry and the National Research Lab of Marine Molecular and Environmental Bioscience, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)]. E-mail: jslee2@hanyang.ac.kr

    2007-07-20

    There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in such efforts. Tigriopus and other copepods are widely distributed and ecologically important organisms. Their position in marine food chains is very prominent, especially with regard to the transfer of energy. Copepods also play an important role in the transportation of aquatic pollutants across the food chains. In recent years there has been a phenomenal increase in the knowledge base of Tigriopus spp., particularly in the areas of their ecology, geophylogeny, genomics and their behavioural, biochemical and molecular responses following exposure to environmental stressors and chemicals. Sequences of a number of important marker genes have been studied in various Tigriopus spp., notably T. californicus and T. japonicus. These genes belong to normal biophysiological functions (e.g. electron transport system enzymes) as well as stress and toxic chemical exposure responses (heat shock protein 20, glutathione reductase, glutathione S-transferase). Recently, 40,740 expressed sequenced tags (ESTs) from T. japonicus, have been sequenced and of them, 5673 ESTs showed significant hits (E-value, >1.0E-05) to the red flour beetle Tribolium genome database. Metals and organic pollutants such as antifouling agents, pesticides, polycyclic aromatic hydrocarbons (PAH) and polychrlorinated biphenyls (PCB) have shown reproducible biological responses when tested in Tigriopus spp. Promising results have been obtained when Tigriopus was used for assessment of risk associated with exposure to endocrine-disrupting chemicals (EDCs). Application of environmental

  6. Astaxanthin dynamics in Baltic Sea mesozooplankton communities

    Science.gov (United States)

    Snoeijs, Pauline; Häubner, Norbert

    2014-01-01

    The red pigment astaxanthin is a powerful antioxidant, which occurs in eggs and body tissues of crustaceans and fish. It is produced by crustaceans from algal carotenoids. In a two-year field study we assessed natural concentrations and dynamics of astaxanthin in mesozooplankton communities in the brackish Baltic Sea area. Astaxanthin levels varied between 0.37 and 36 ng L- 1. They increased with salinity along the Baltic Sea gradient and were linked to zooplankton biomass and phytoplankton community composition. Astaxanthin concentrations showed typical seasonal patterns and varied from 0.2 to 5.1 ng ind- 1, 0.2 to 3.4 ng (μg C)- 1 and 6 to 100 ng mm- 3. These concentrations were inversely related to water temperature and strongly linked to zooplankton community composition. Communities dominated by the calanoid copepods Temora longicornis, Pseudocalanus acuspes and Eurytemora spp. generally held the highest concentrations. With increasing cladocerans:copepods biomass ratios community astaxanthin concentrations decreased and with higher relative biomass of Acartia spp. the proportion of astaxanthin diesters decreased. Diesters prevailed in the cold season and they are thought to improve the antioxidant protection of storage lipids during winter. Climate change causes higher temperature and lower salinity in the Baltic Sea proper. This modifies zooplankton community composition, but not necessarily into a community with lower concentrations of astaxanthin since T. longicornis (high concentrations) has been reported to increase with higher temperature. However, decreased astaxanthin production in the ecosystem is expected if a basin-wide increase in the cladocerans:copepods biomass ratios would occur with further climate change.

  7. Primers to block the amplification of symbiotic apostome ciliate 18S rRNA gene in a PCR-based copepod diet study

    Science.gov (United States)

    Yi, Xiaoyan; Zhang, Huan; Liu, Guangxing

    2014-05-01

    Pelagic copepods play an important role in the marine food web. However, a full understanding of the ecological status of this zooplankton group depends on the careful study of their natural diets. In previous PCR-based copepod diet studies, we found many apostome ciliates that live symbiotically under the exoskeleton of the copepods, and their sequences were often over-represented in the 18S rRNA gene (18S rDNA) libraries. As a first step to address this issue, we designed three apostome ciliate 18S rDNA blocking primers, and tested their blocking efficiency against apostome ciliate 18s rDNA under various PCR conditions. Using a semi-quantitative PCR method, we optimized the conditions to efficiently amplify the 18S rDNA of the prey while simultaneously excluding the symbiotic apostome ciliates. This technique will facilitate PCR-based diet studies of copepods and other zooplankton in their natural environments.

  8. Zooplankton variability and copepod assemblage in the coastal and estuarine waters of Goa along the central-west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Ramaiah, Neelam; Padmavati, G.

    Seasonal variations in zooplankton distribution and community structure of copepod species in coastal and estuarine waters of Goa along the central-west coast of India are compared in relation to water temperature, salinity and dissoved oxygen...

  9. A cost-effectiveness analysis of live feeds in juvenile turbot Scophthalmus maximus (Linnaeus, 1758) farming: copepods versus Artemiapepods versus Artemiacopepods versus Artemiacopepods versus Artemia

    DEFF Research Database (Denmark)

    Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max;

    2016-01-01

    , their current usage is quite limited. One of the reasons has been lack of economic knowledge concerning the cost-effectiveness of copepod application compared to other commonly used feed items such as the brine shrimp Artemia. In this study, a cost-effectiveness analysis is made on two alternative live feed...... but they are also economically a cost-effective alternative. Thus, a commercial use of copepods will significantly reduce the production costs for turbot. Furthermore, the unexploited economic potential can be utilized for the successful farming of other high-valued marine finfish species such as tuna, flounders...... items (copepods and Artemia) in juvenile turbot farming. Unit cost of production and profit are compared between the two feeding regimes using a unique data set from an existing turbot fry production facility in Denmark. The result reveals that copepods are not only biochemically superior...

  10. Functional coadaptation between cytochrome c and cytochrome c oxidase within allopatric populations of a marine copepod.

    Science.gov (United States)

    Rawson, Paul D; Burton, Ronald S

    2002-10-01

    Geographically isolated populations may accumulate alleles that function well on their own genetic backgrounds but poorly on the genetic backgrounds of other populations. Consequently, interpopulation hybridization may produce offspring of low fitness as a result of incompatibilities arising in allopatry. Genes participating in these epistatic incompatibility systems remain largely unknown. In fact, despite the widely recognized importance of epistatic interactions among gene products, few data directly address the functional consequences of such interactions among natural genetic variants. In the marine copepod, Tigriopus californicus, we found that the cytochrome c variants isolated from two different populations each had significantly higher activity with the cytochrome c oxidase derived from their respective source population. Three amino acid substitutions in the cytochrome c protein appear to be sufficient to confer population specificity. These results suggest that electron transport system (ETS) proteins form coadapted sets of alleles within populations and that disruption of the coadapted ETS gene complex leads to functional incompatibilities that may lower hybrid fitness.

  11. Phylogeography of the intertidal copepod Tigriopus californicus reveals substantially reduced population differentiation at northern latitudes.

    Science.gov (United States)

    Edmands, S

    2001-07-01

    Previous studies of the intertidal copepod Tigriopus californicus revealed one of the highest levels of mitochondrial DNA differentiation ever reported among conspecific populations. The present study extends the geographical sampling northward, adding populations from northern California to south-east Alaska. The mitochondrial phylogeny for the entire species range, based on cytochrome oxidase I sequences for a total of 49 individuals from 27 populations, again shows extreme differentiation among populations (up to 23%). However, populations from Oregon northwards appear to be derived and have interpopulation divergences five times lower than those between southern populations. Furthermore, although few individuals were sequenced from each locality, populations from Puget Sound northward had significantly reduced levels of within-population variation. These patterns are hypothesized to result from the contraction and expansion of populations driven by recent ice ages.

  12. Trade-offs, geography, and limits to thermal adaptation in a tide pool copepod.

    Science.gov (United States)

    Kelly, Morgan W; Grosberg, Richard K; Sanford, Eric

    2013-06-01

    Antagonistic correlations among traits may slow the rate of adaptation to a changing environment. The tide pool copepod Tigriopus californicus is locally adapted to temperature, but within populations, the response to selection for increased heat tolerance plateaus rapidly, suggesting either limited variation within populations or costs of increased tolerance. To measure possible costs of thermal tolerance, we selected for increased upper lethal limits for 10 generations in 22 lines of T. californicus from six populations. Then, for each line, we measured six fitness-related traits. Selected lines showed an overall increase in male and female body sizes, fecundity, and starvation resistance, suggesting a small benefit from (rather than costs of) increased tolerance. The effect of selection on correlated traits also varied significantly by population for five traits, indicating that the genetic basis for the selection response differed among populations. Our results suggest that adaptation was limited by the presence of variation within isolated populations rather than by costs of increased tolerance.

  13. Bacterial exopolymer utilization by a harpacticoid copepod: A methodology and results

    Energy Technology Data Exchange (ETDEWEB)

    Decho, A.W.; Moriarty, D.J.W. (C.S.I.R.O. Marine Labs., Cleveland (Australia))

    1990-07-01

    Exopolymer mucus secretions of bacteria and diatoms are potential foods for benthic animals. These secretions are coincidently ingested by animals during consumption of microbial cells and sediments. The utilization of microbial secretions was investigated with exopolymer derived from a marine bacterium (pseudomonas sp.) from seagrass beds and a harpacticoid copepod Laophonte sp. from the same habitat. A new technique was developed to examine ingestion, absorption, and absorption efficiencies of these bacterial secretions by consumers. Exopolymer mucus (from the bacterium in stationary phase) was labeled with {sup 14}C, collected, purified, and bound onto bacterium-sized beads. The exopolymer slime coating mimicked the coatings associated with many marine bacteria. Results from feeding experiments where the coated beads were mixed with sediment demonstrated that the mucus-exopolymer secretions of bacteria were ingested and utilized by Laophonte sp. Absorption efficiencies, determined directly, were > 80% in the presence of other food resources, indicating that exopolymer is potentially a highly labile C resource for this animal.

  14. Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic.

    Science.gov (United States)

    Jónasdóttir, Sigrún Huld; Visser, André W; Richardson, Katherine; Heath, Michael R

    2015-09-29

    Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a "lipid shunt," and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic.

  15. A global synthesis of seasonal temperature-size responses in copepods

    DEFF Research Database (Denmark)

    Horne, Curtis R.; Hirst, Andrew G.; Atkinson, David;

    2016-01-01

    variation in adult body mass within seasonally varying marine and freshwater environments. We describe how size variation relates to temperature, food concentration (chlorophyll-a) and life-history characteristics, including feeding strategy.Location Global.Methods Using a meta-analytic approach we extract......Aim Body size is a master trait with significant ecological importance. Seasonal changes in body size within diverse ectothermic species can result from different environmental conditions experienced during ontogeny in subsequent generations. Whilst intraspecific changes in adult size have been...... seasonal size responses from 33 different global locations, representing 48 planktonic copepod species from four taxonomic orders. We find that temperature (r(2) = 0.50), rather than food (r(2) = 0.22), is the dominant explanatory variable of changes in adult body size across seasons. A striking outcome...

  16. Changes in selection regime cause loss of phenotypic plasticity in planktonic freshwater copepods.

    Science.gov (United States)

    Sereda, Sergej Vital'evič; Wilke, Thomas; Schultheiß, Roland

    2014-01-01

    Rapid phenotypic adaptation is critical for populations facing environmental changes and can be facilitated by phenotypic plasticity in the selected traits. Whereas recurrent environmental fluctuations can favour the maintenance or de novo evolution of plasticity, strong selection is hypothesized to decrease plasticity or even fix the trait (genetic assimilation). Despite advances in the theoretical understanding of the impact of plasticity on diversification processes, comparatively little empirical data of populations undergoing diversification mediated by plasticity are available. Here we use the planktonic freshwater copepod Acanthodiaptomus denticornis from two lakes as model system to study UV stress responses of two phenotypically different populations under laboratory conditions. Our study reveals heritable lake- and sex-specific differences of behaviour, physiological plasticity, and mortality. We discuss specific selective scenarios causing these differences and argue that phenotypic plasticity will be higher when selection pressure is moderate, but will decrease or even be lost under stronger pressure.

  17. Mitochondrial DNA polymorphism (CO1) of three dominant copepod species in the South Atlantic

    Science.gov (United States)

    Stupnikova, A. N.; Kulagin, D. N.; Neretina, T. V.; Mugue, N. S.

    2013-07-01

    The Southern Ocean is characterized by the complex system of oceanic fronts that maintain the latitudinal zonality of biotopes. These fronts are boundaries of water masses with different hydrophysical characteristics. We explore the genetic differentiation of the dominant zooplankton species in regards to the complex hydrophysical zonality of the Southern Ocean. The barcoding region of mitochondrial CO1 gene was sequenced for three copepod species, Calanus simillimus, Rhincalanus gigas, and Metridia lucens. These species are the most abundant in the Southern Ocean and form the basis of the zooplankton community. Genetic differentiation was found neither for Calanus simillimus nor for Rhincalanus gigas. The mitochondrial haplotypes of Metridia lucens cluster in two genetically distant groups (Subantarctic and Antarctic) found together only in the Polar Front Zone.

  18. Life cycle of Schizochytriodinium calani nov. gen. nov. spec., a dinoflagellate parasitizing copepod eggs

    Science.gov (United States)

    Elbrächter, Malte

    1988-09-01

    During the Polarstern-cruise ARK IV/2 June 1987, in the Fram Strait, dinophytes parasitizing copepod eggs were observed. In the laboratory on board, vegetative reproduction was documented and re-infection of Calanus glacialis and C. hyperboreus eggs was experimentally established. During food uptake, a primary cyst produces successively several secondary cysts, all separating immediately after formation from the primary cyst. In every one of these free floating secondary cysts up to 256 dinospores are formed by palintomy. Re-infection only occurred after a “maturation time” of at least 2 days after formation of the dinospores. The life cycle is compared to that of other similar parasitic dinophyte genera: Apodinium Chatton, Chytriodinium Chatton, Dissodinium Klebs in Pascher and Myxodinium Cachon, Cachon & Bouquaheux. As the taxon under discussion does not fit in with any species or genus known so far, it is described as Schizochytriodinium calani nov. gen. nov. spec.

  19. Age- and size-dependent mating performance and fertility in a pelagic copepod, Temora longicornis

    DEFF Research Database (Denmark)

    Sichlau, Mie Hylstofte; Kiørboe, Thomas

    2011-01-01

    Prepress abstract: In many species, size and age have been shown to be strong determinants of the reproductive success for both sexes. Here we examine age- and size dependent reproductive performance (egg- and sperm production, mating success) in a pelagic copepod. Compared to smaller males, larger...... males produce larger spermatophores containing more spermatozoa, and fertilize a larger fraction of available females. Females mating with large males produce more offspring than those mating with small males. Similarly, large females have higher egg production rates as well as a higher life-time egg...... production than small females. Ageing effects are evident in this species: Mortality rate increases and fertility decreases rapidly with age. The average adult longevity under optimal laboratory conditions was 30 days in both males and females, but females produce eggs for only 18 days, and males can...

  20. Syltodinium listii gen. et spec. nov., a marine ectoparasitic dinoflagellate on eggs of copepods and rotifers

    Science.gov (United States)

    Drebes, Gerhard

    1988-09-01

    Syltodinium listii is described as a new marine ectoparasitic dinoflagellate. In culture experiments the species was found feeding on eggs of planktonic copepods and rotifers. The dinospore penetrates the host by a peduncle, and transforms into a trophont by sucking out the egg contents phagotrophically. After detaching from the host, the mature trophont settles down to become a palmelloid multiplication stage. By repeated binary fission, up to 16 or 32 gymnodinoid, colourless dinospores are formed inside a gelatinous envelope. The parasite retains its dinoflagellate (monadoid) nature throughout its whole vegetative life cycle. Even during the trophic and multiplication phase the species remains latently motile. Despite some resemblance to Dissodinium, there are sufficient reasons for the establishment of the new genus Syltodinium.

  1. Biosynthesis of coelenterazine in the deep-sea copepod, Metridia pacifica

    Energy Technology Data Exchange (ETDEWEB)

    Oba, Yuichi; Kato, Shin-ichi; Ojika, Makoto [Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-860 (Japan); Inouye, Satoshi, E-mail: sinouye@chisso.co.jp [Yokohama Research Center, Chisso Co., 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605 (Japan)

    2009-12-18

    Coelenterazine is an imidazopyrazinone compound (3,7-dihydroimidazopyrazin-3-one structure) that is widely distributed in marine organisms and used as a luciferin for various bioluminescence reactions. We have used electrospray ionization-ion trap-mass spectrometry to investigate whether the deep-sea luminous copepod Metridia pacifica is able to synthesize coelenterazine. By feeding experiments using deuterium labeled amino acids of L-tyrosine and L-phenylalanine, we have shown that coelenterazine can be synthesized from two molecules of L-tyrosine and one molecule of L-phenylalanine in M. pacifica. This is the first demonstration that coelenterazine is biosynthesized from free L-amino acids in a marine organism.

  2. A gene-based SNP resource and linkage map for the copepod Tigriopus californicus

    Directory of Open Access Journals (Sweden)

    Foley Brad R

    2011-11-01

    Full Text Available Abstract Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct a linkage map dense enough for quantitative trait locus detection in an interval mapping framework for T. californicus--a first for copepods. Results One hundred and ninety Single Nucleotide Polymorphisms (SNPs were used to genotype our mapping population of 250 F2 larvae. We were able to construct a linkage map with an average intermarker distance of 1.8 cM, and a maximum intermarker distance of 10.3 cM. All markers were assembled into linkage groups, and the 12 linkage groups corresponded to the 12 known chromosomes of T. californicus. We estimate a total genome size of 401.0 cM, and a total coverage of 73.7%. Seventy five percent of the mapped markers were detected in 9 additional populations of T. californicus. Of available model arthropod genomes, we were able to show more colocalized pairs of homologues between T. californicus and the honeybee Apis mellifera, than expected by chance, suggesting preserved macrosynteny between Hymenoptera and Copepoda. Conclusions Our study provides an abundance of linked markers spanning all chromosomes. Many of these markers are also found in multiple populations of T. californicus, and in two other species in the genus. The genomic resource we have developed will enable mapping throughout the geographical range of this species and in closely related species. This linkage map will facilitate genome sequencing, mapping and assembly in an ecologically and taxonomically interesting group for which genomic resources are

  3. Distribution of Pleuromamma (Copepoda: Metridiidae) along a north-south transect in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Gajbhiye, S.N.; Padmavati, G.

    Distribution and abundance of calanoid copepods of the genus Pleuromamma Giesbrecht 1898 along a north-south transect in the Indian Ocean were studied. Seven species such as Pleuromamma indica, P. abdominalis, P. gracilis, P. xiphias, P...

  4. Epibionts and parasites on crustaceans (Copepoda, Cladocera, Cirripedia larvae inhabiting the Gulf of Gdańsk (Baltic Sea in very large numbers* This work was supported in part by grant No. BW/1320-5-0183-3 from the University of Gdańsk.

    Directory of Open Access Journals (Sweden)

    Luiza Bielecka

    2014-06-01

    Infestation by epibionts and parasites was not restricted to calanoid copepods: it was also detected in non-negligible numbers on other crustaceans, namely, Harpacticoida, Cladocera (Bosmina sp. and Cirripedia larvae (nauplii in the Gulf of Gdańsk.

  5. New species of Pseudodiaptomus (Copepoda: Calanoida) from the salt pans of the Gulf of Kutch, India and a comment on its speciation

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.

    A new species of calanoid copepod Pseudodiaptomus pankajus (family Pseudodiaptomidae) is described from the north-west coast of India. This species inhabits high saline waters of salt pans. It appears to have evolved allopatrically during...

  6. Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna in the pelagic eastern Pacific Ocean

    Science.gov (United States)

    Olson, Robert J.; Popp, Brian N.; Graham, Brittany S.; López-Ibarra, Gladis A.; Galván-Magaña, Felipe; Lennert-Cody, Cleridy E.; Bocanegra-Castillo, Noemi; Wallsgrove, Natalie J.; Gier, Elizabeth; Alatorre-Ramírez, Vanessa; Ballance, Lisa T.; Fry, Brian

    2010-07-01

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and yellowfin tuna ( Thunnus albacares), and to quantify yellowfin tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ 15N values of several omnivorous copepod species, we examined isotopic spatial relationships among yellowfin tuna and copepods. We found a broad-scale, uniform gradient in δ 15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ 15N values in the white muscle of yellowfin tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ 15N values at the base of the food web, the isotopic difference between these two taxa, “ ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk δ 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic

  7. Effect of the copepod parasite Nicothoë astaci on haemolymph chemistry of the European lobster Homarus gammarus.

    Science.gov (United States)

    Davies, Charlotte E; Vogan, Claire L; Rowley, Andrew F

    2015-03-09

    The gills of the European lobster Homarus gammarus (L.) are susceptible to parasitization by the copepod Nicothoë astaci, the lobster louse. This copepod feeds on haemolymph of the host and can damage the gills, potentially affecting gaseous exchange capabilities. To investigate the host response to the parasite, haemolymph levels of total protein, haemocyanin, glucose and ammonia were quantified in adult lobsters carrying varying parasite loads. Parasite loads correlated positively with total haemolymph protein and haemocyanin concentrations but not with glucose or ammonia concentrations. The data suggest that lobsters with gills damaged by the feeding activities of N. astaci respond by producing higher levels of haemocyanin, which is both a key defence response and may compensate for their decreased respiratory functioning.

  8. Effects of Demersal Otter Trawls on the Re-suspension of Copepod Resting Eggs and its Potential Effects on Recruitment

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume; Hay, G;

    2014-01-01

    -suspension and the hatching success of copepod resting eggs in the wake of two different demersal fishing gear components (doors and discs) that are in contact with the seabed, in two areas off the coast of Scotland that are rarely worked by fishermen. Sediment cores were taken and analysed for resting eggs quantity......Resting eggs are important phases in the life strategy of many coastal and estuarine copepods. The egg mortality in the sediment layers where they are buried, as well as re-suspension from the sediment into the water column where eggs may hatch are factors that affect the success of this life...... and hatching performance and compared with samples taken in the water column right after re-suspension of sediment by the gear components. This study demonstrated for the first time that although eggs are re-suspended in the water column together with the sediment, providing them with the opportunity to hatch...

  9. Nuclear and mitochondrial gene genealogies and allozyme polymorphism across a major phylogeographic break in the copepod Tigriopus californicus.

    OpenAIRE

    Burton, R S; Lee, B. N.

    1994-01-01

    The genetic structure of natural populations is frequently inferred from geographic distributions of alleles at multiple gene loci. Surveys of allozyme polymorphisms in the tidepool copepod Tigriopus californicus have revealed sharp genetic differentiation of populations, indicating that gene flow among populations is highly restricted. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial gene genealogies. DNA sequences of the mtDNA-encod...

  10. Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice.

    Science.gov (United States)

    Lewis, Ceri N; Brown, Kristina A; Edwards, Laura A; Cooper, Glenn; Findlay, Helen S

    2013-12-17

    The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their current under-ice winter ecology on which to base future monitoring or make predictions about climate-induced change. Here, we report results from Arctic under-ice investigations of copepod natural distributions associated with late-winter carbonate chemistry environmental data and their response to manipulated pCO2 conditions (OA exposures). Our data reveal that species and life stage sensitivities to manipulated OA conditions were correlated with their vertical migration behavior and with their natural exposures to different pCO2 ranges. Vertically migrating adult Calanus spp. crossed a pCO2 range of >140 μatm daily and showed only minor responses to manipulated high CO2. Oithona similis, which remained in the surface waters and experienced a pCO2 range of <75 μatm, showed significantly reduced adult and nauplii survival in high CO2 experiments. These results support the relatively untested hypothesis that the natural range of pCO2 experienced by an organism determines its sensitivity to future OA and highlight that the globally important copepod species, Oithona spp., may be more sensitive to future high pCO2 conditions compared with the more widely studied larger copepods.

  11. The parasitic dinoflagellates Blastodinium spp. inhabiting the gut of marine, planktonic copepods: morphology, ecology and unrecognized species diversity

    Directory of Open Access Journals (Sweden)

    Alf eSkovgaard

    2012-08-01

    Full Text Available Blastodinium is a genus of dinoflagellates that live as parasites in the gut of marine, planktonic copepods in the World’s oceans and coastal waters. The taxonomy, phylogeny and physiology of the genus has only been explored to a limited degree and, based on recent investigations, we hypothesize that the morphological and genetic diversity within this genus may be considerably larger than presently recognized. To address these issues, we obtained 18S rDNA and ITS gene sequences for Blastodinium specimens of different geographical origins, including representatives of the type species. This genetic information was in some cases complemented with new morphological, ultrastructural, physiological and ecological data. Because most current knowledge about Blastodinium and its effects on copepod hosts stem from publications more than half a century old, we here summarize and discuss the existing knowledge in relation to the new data generated. Most Blastodinium species possess functional chloroplasts, but the parasitic stage, the trophocyte, has etioplasts and probably a limited photosynthetic activity. Sporocytes and swarmer cells have well developed plastids and plausibly acquire part of their organic carbon needs through photosynthesis. A few species are nearly colourless with no functional chloroplasts. The photosynthetic species are almost exclusively found in warm, oligotrophic waters, indicating a life strategy that may benefit from copepods as microhabitats for acquiring nutrients in a nutrient-limited environment. As reported in the literature, monophyly of the genus is moderately supported, but the three main groups proposed by Chatton in 1920 are consistent with molecular data. However, we demonstrate an important genetic diversity within the genus and present evidences for new groups and the presence of cryptic species. Finally, we discuss the current knowledge on the occurrence of Blastodinium spp. and their potential impact on natural

  12. The Parasitic Dinoflagellates Blastodinium spp. Inhabiting the Gut of Marine, Planktonic Copepods: Morphology, Ecology, and Unrecognized Species Diversity

    Science.gov (United States)

    Skovgaard, Alf; Karpov, Sergey A.; Guillou, Laure

    2012-01-01

    Blastodinium is a genus of dinoflagellates that live as parasites in the gut of marine, planktonic copepods in the World’s oceans and coastal waters. The taxonomy, phylogeny, and physiology of the genus have only been explored to a limited degree and, based on recent investigations, we hypothesize that the morphological and genetic diversity within this genus may be considerably larger than presently recognized. To address these issues, we obtained 18S rDNA and ITS gene sequences for Blastodinium specimens of different geographical origins, including representatives of the type species. This genetic information was in some cases complemented with new morphological, ultrastructural, physiological, and ecological data. Because most current knowledge about Blastodinium and its effects on copepod hosts stem from publications more than half a century old, we here summarize and discuss the existing knowledge in relation to the new data generated. Most Blastodinium species possess functional chloroplasts, but the parasitic stage, the trophocyte, has etioplasts and probably a limited photosynthetic activity. Sporocytes and swarmer cells have well-developed plastids and plausibly acquire part of their organic carbon needs through photosynthesis. A few species are nearly colorless with no functional chloroplasts. The photosynthetic species are almost exclusively found in warm, oligotrophic waters, indicating a life strategy that may benefit from copepods as microhabitats for acquiring nutrients in a nutrient-limited environment. As reported in the literature, monophyly of the genus is moderately supported, but the three main groups proposed by Chatton in 1920 are consistent with molecular data. However, we demonstrate an important genetic diversity within the genus and provide evidences for new groups and the presence of cryptic species. Finally, we discuss the current knowledge on the occurrence of Blastodinium spp. and their potential impact on natural copepod

  13. Molecular characterization and expression of vitellogenin (Vg) genes from the cyclopoid copepod, Paracyclopina nana exposed to heavy metals.

    Science.gov (United States)

    Hwang, Dae-Sik; Lee, Kyun-Woo; Han, Jeonghoon; Park, Heum Gi; Lee, Jehee; Lee, Young-Mi; Lee, Jae-Seong

    2010-04-01

    Induction of vitellogenin (Vg) has been used as a biomarker of exposure to heavy metals and endocrine-disruption chemicals (EDCs) in aquatic organisms. Here, we identified the full-length Vg1 and Vg2 sequence from the brackish water copepod, Paracyclopina nana. Vg1 gene contained 5718bp of the open reading frame (ORF) that encoded the putative protein of 1905 amino acids residues, while Vg2 gene consisted of 5442bp of ORF, encoding the putative protein of 1813 amino acids residues. P. nana Vgs showed highly conserved domains in the N-terminal region. The phylogenetic analysis revealed that P. nana Vgs are distinct from other arthropods, such as insects and decapods, as it formed a clade with other copepods, Tigriopus japonicus and salmon louse (Lepeophtheirus salmonis). The expression of Vg transcripts was detectable after the copepodid stages 4-5. Female copepods expressed over 83 times and 223 times more Vg1 and Vg2 transcripts, respectively, than males. When copepods were exposed to heavy metals (0.1mg/L Cd, 0.4mg/L Cu, and 2mg/L AsIII) for 24, 48, 72, and 96h, P. nana Vg transcripts were highly induced in a time-dependent manner. Interestingly, Vg2 gene was more susceptible than Vg1 to trace heavy metal exposure. This finding indicates that P. nana Vgs provide a potential indicator for assessing the toxic effect of heavy metals. In addition, we suggest P. nana as a potential model species for risk-assessment to environmental pollutants in brackish water.

  14. The minute brain of the copepod Tigriopus californicus supports a complex ancestral ground pattern of the tetraconate cerebral nervous systems.

    Science.gov (United States)

    Andrew, David R; Brown, Sheena M; Strausfeld, Nicholas J

    2012-10-15

    Copepods are a diverse and ecologically crucial group of minute crustaceans that are relatively neglected in terms of studies on nervous system organization. Recently, morphological neural characters have helped clarify evolutionary relationships within Arthropoda, particularly among Tetraconata (i.e., crustaceans and hexapods), and indicate that copepods occupy an important phylogenetic position relating to both Malacostraca and Hexapoda. This taxon therefore provides the opportunity to evaluate those neural characters common to these two clades likely to be results of shared ancestry (homology) versus convergence (homoplasy). Here we present an anatomical characterization of the brain and central nervous system of the well-studied harpacticoid copepod species Tigriopus californicus. We show that this species is endowed with a complex brain possessing a central complex comprising a protocerebral bridge and central body. Deutocerebral glomeruli are supplied by the antennular nerves, and a lateral protocerebral olfactory neuropil corresponds to the malacostracan hemiellipsoid body. Glomeruli contain synaptic specializations comparable to the presynaptic "T-bars" typical of dipterous insects, including Drosophila melanogaster. Serotonin-like immunoreactivity pervades the brain and ventral nervous system, with distinctive deutocerebral distributions. The present observations suggest that a suite of morphological characters typifying the Tigriopus brain reflect a ground pattern organization of an ancestral Tetraconata, which possessed an elaborate and structurally differentiated nervous system.

  15. The metabolic response of marine copepods to environmental warming and ocean acidification in the absence of food

    Science.gov (United States)

    Mayor, Daniel J.; Sommer, Ulf; Cook, Kathryn B.; Viant, Mark R.

    2015-09-01

    Marine copepods are central to the productivity and biogeochemistry of marine ecosystems. Nevertheless, the direct and indirect effects of climate change on their metabolic functioning remain poorly understood. Here, we use metabolomics, the unbiased study of multiple low molecular weight organic metabolites, to examine how the physiology of Calanus spp. is affected by end-of-century global warming and ocean acidification scenarios. We report that the physiological stresses associated with incubation without food over a 5-day period greatly exceed those caused directly by seawater temperature or pH perturbations. This highlights the need to contextualise the results of climate change experiments by comparison to other, naturally occurring stressors such as food deprivation, which is being exacerbated by global warming. Protein and lipid metabolism were up-regulated in the food-deprived animals, with a novel class of taurine-containing lipids and the essential polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid and docosahexaenoic acid, changing significantly over the duration of our experiment. Copepods derive these PUFAs by ingesting diatoms and flagellated microplankton respectively. Climate-driven changes in the productivity, phenology and composition of microplankton communities, and hence the availability of these fatty acids, therefore have the potential to influence the ability of copepods to survive starvation and other environmental stressors.

  16. Acute toxicity of dispersed crude oil on the cold-water copepod Calanus finmarchicus: Elusive implications of lipid content.

    Science.gov (United States)

    Hansen, Bjørn Henrik; Jager, Tjalling; Altin, Dag; Øverjordet, Ida B; Olsen, Anders J; Salaberria, Iurgi; Nordtug, Trond

    2016-01-01

    In this investigation, acute toxicity data were used from two previously reported studies where cold-water copepods were exposed to mechanically dispersed (MD) and chemically (CD) dispersed oil. In one of these studies, concentration-dependent mortality was observed, whereas no apparent relationship between exposure concentration and mortality was found in the other. The only marked difference between the studies is that copepods in the first experiment displayed a lower lipid sac volume (on average) than in the second one. In this study additional biometric data on lipid content were utilized and observed effects and toxicokinetics modeling applied in order to investigate whether differences in sensitivity between copepod cohorts might be explained by differences in lipid content. Results suggest that although a considerable lipid sac might retard toxicokinetics, the observed differences in lipid volume are not sufficient to explain differences in toxicity. Further, there are no apparent indications that acute toxic stress leads to lipid depletion, or that acute increased mortality rate selectively affects lipid-poor individuals. It is conceivable that other potential explanations exist, but the causal relationship between lipid content and increased mortality frequency remains elusive.

  17. Identification and molecular characterization of dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana.

    Science.gov (United States)

    Jeong, Chang-Bum; Lee, Min Chul; Lee, Kyun-Woo; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2015-12-01

    To date, knowledge of the immune system in aquatic invertebrates has been reported in only a few model organisms, even though all metazoans have an innate immune system. In particular, information on the copepod's immunity and the potential role of key genes in the innate immune systems is still unclear. In this study, we identified dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana. In silico analyses for identifying conserved domains and phylogenetic relationships supported their gene annotations. The transcriptional levels of both genes were slightly increased from the nauplius to copepodid stages, suggesting that these genes are putatively involved in copepodid development of P. nana. To examine the involvement of both genes in the innate immune response and under stressful conditions, the copepods were exposed to lipopolysaccharide (LPS), different culture densities, salinities, and temperatures. LPS significantly upregulated mRNA expressions of dorsal and dorsal-like genes, suggesting that both genes are transcriptionally sensitive in response to immune modulators. Exposure to unfavorable culture conditions also increased mRNA levels of dorsal and dorsal-like genes. These findings suggest that transcriptional regulation of the dorsal and dorsal-like genes would be associated with environmental changes in P. nana.

  18. Response of antioxidant defense system in copepodCalanus sinicus Brodsky exposed to CO2-acidified seawater

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dajuan; GUO Donghui; WANG Guizhong; LI Shaojing

    2016-01-01

    Marine zooplankton responds sensitively to elevated seawater CO2 concentration. However, the underlying physiological mechanisms have not been studied well. We therefore investigated the effects of elevated CO2 concentration (0.08%, 0.20%, 0.50% and 1.00%) on antioxidant defense components, as well as two detoxification enzymes ofCalanus sinicus (copepod). The results showed that glutathione peroxidase (GPx) activity exposed to CO2-acidified seawater was significantly stimulated while other antioxidant components, including glutathione-S-transferase (GST) activity, superoxide dismutase (SOD) activity decreased significantly with reduced glutathione (GSH) level and GSH/oxidized glutathione (GSSG) value. CO2-acidified seawater exhibited stimulatory effects on adenosine triphosphatase (ATPase) activity and acetylcholinesterase (AchE) activity was inhibited. Moreover, the results of principal component analysis indicated that 75.93% of the overall variance was explained by the first two principal components. The elevated CO2 concentration may affect the metabolism and survivals of copepods through impacts these enzymes activities. Further studies are needed to focus on the synergistic effects of elevated CO2 concentration and other environmental factors on copepods.

  19. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L. larvae — can we identify the underlying factors?

    Directory of Open Access Journals (Sweden)

    Ørjan Karlsen

    2015-05-01

    Full Text Available The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1, groups of cod larvae were fed either (a natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b enriched rotifers followed by Artemia (the intensive group. In the second experiment (Exp-2, two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5 after the fish had been fed the same formulated diet for approximately 2 weeks.

  20. Growth of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia estimated from laboratory experiments

    Directory of Open Access Journals (Sweden)

    LRP. Utz

    Full Text Available Peritrich ciliates are commonly found colonizing living substrates. Although this a well known phenomenon, biological aspects of this relationship need to be studied in more detail. Assessment of growth rates in peritrichs has been the subject of very few studies. Only species in the genera Carchesium Ehrenberg, 1830 and Vorticella Linnaeus, 1767 had their growth rates evaluated in the field and in the laboratory. In the present study, growth, colonization (colonies/host, and proliferation (zooids/colony rates of the peritrich epibiont Zoothamnium intermedium Precht, 1935 attached to the calanoid copepod Acartia tonsa Dana 1848 were evaluated in the laboratory in two food regimes: bacteria only, and algal based diet. Results showed that growth, colonization, and proliferation rates were similar for both diets. Maximum growth rates obtained for Z. intermedium was 0.85 and 0.83 per day, for bacteria and algae respectively. Maximum colonization rates were 0.5 per day for both diets, and the maximum proliferation rates were 0.44 and 0.42 per day for bacteria and algae respectively. These results demonstrate that Z. intermedium is able to grow at the same rate of other peritrichs on bacterial and algal based diets.

  1. Growth of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) estimated from laboratory experiments.

    Science.gov (United States)

    Utz, L R P

    2008-05-01

    Peritrich ciliates are commonly found colonizing living substrates. Although this a well known phenomenon, biological aspects of this relationship need to be studied in more detail. Assessment of growth rates in peritrichs has been the subject of very few studies. Only species in the genera Carchesium Ehrenberg, 1830 and Vorticella Linnaeus, 1767 had their growth rates evaluated in the field and in the laboratory. In the present study, growth, colonization (colonies/host), and proliferation (zooids/colony) rates of the peritrich epibiont Zoothamnium intermedium Precht, 1935 attached to the calanoid copepod Acartia tonsa Dana 1848 were evaluated in the laboratory in two food regimes: bacteria only, and algal based diet. Results showed that growth, colonization, and proliferation rates were similar for both diets. Maximum growth rates obtained for Z. intermedium was 0.85 and 0.83 per day, for bacteria and algae respectively. Maximum colonization rates were 0.5 per day for both diets, and the maximum proliferation rates were 0.44 and 0.42 per day for bacteria and algae respectively. These results demonstrate that Z. intermedium is able to grow at the same rate of other peritrichs on bacterial and algal based diets.

  2. Elevated oxidative damage is correlated with reduced fitness in interpopulation hybrids of a marine copepod.

    Science.gov (United States)

    Barreto, Felipe S; Burton, Ronald S

    2013-09-22

    Aerobic energy production occurs via the oxidative phosphorylation pathway (OXPHOS), which is critically dependent on interactions between the 13 mitochondrial DNA (mtDNA)-encoded and approximately 70 nuclear-encoded protein subunits. Disruptive mutations in any component of OXPHOS can result in impaired ATP production and exacerbated oxidative stress; in mammalian systems, such mutations are associated with ageing as well as numerous diseases. Recent studies have suggested that oxidative stress plays a role in fitness trade-offs in life-history evolution and functional ecology. Here, we show that outcrossing between populations with divergent mtDNA can exacerbate cellular oxidative stress in hybrid offspring. In the copepod Tigriopus californicus, we found that hybrids that showed evidence of fitness breakdown (low fecundity) also exhibited elevated levels of oxidative damage to DNA, whereas those with no clear breakdown did not show significantly elevated damage. The extent of oxidative stress in hybrids appears to be dependent on the degree of genetic divergence between their respective parental populations, but this pattern requires further testing using multiple crosses at different levels of divergence. Given previous evidence in T. californicus that hybridization disrupts nuclear/mitochondrial interactions and reduces hybrid fitness, our results suggest that such negative intergenomic epistasis may also increase the production of damaging cellular oxidants; consequently, mtDNA evolution may play a significant role in generating postzygotic isolating barriers among diverging populations.

  3. Fitness and morphological outcomes of many generations of hybridization in the copepod Tigriopus californicus.

    Science.gov (United States)

    Pritchard, V L; Knutson, V L; Lee, M; Zieba, J; Edmands, S

    2013-02-01

    Hybridization between genetically divergent populations is an important evolutionary process, with an outcome that is difficult to predict. We used controlled crosses and freely mating hybrid swarms, followed for up to 30 generations, to examine the morphological and fitness consequences of interpopulation hybridization in the copepod Tigriopus californicus. Patterns of fitness in two generations of controlled crosses were partly predictive of long-term trajectories in hybrid swarms. For one pair of populations, controlled crosses revealed neutral or beneficial effects of hybridization after the F1 generation, and hybrid swarm fitness almost always equalled or exceeded that of the midparent. For a second pair, controlled crosses showed F2 hybrid breakdown, but increased fitness in backcrosses, and hybrid swarm fitness deviated both above and below that of the parentals. Nevertheless, individual swarm replicates exhibited different fitness trajectories over time that were not related in a simple manner to their hybrid genetic composition, and fixation of fitter hybrid phenotypes was not observed. Hybridization did not increase overall morphological variation, and underlying genetic changes may have been masked by phenotypic plasticity. Nevertheless, one type of hybrid swarm exhibited a repeatable pattern of transgressively large eggsacs, indicating a positive effect of hybridization on individual fecundity. Additionally, both parental and hybrid swarms exhibited common phenotypic trends over time, indicating common selective pressures in the laboratory environment. Our results suggest that, in a system where much work has focused on F2 hybrid breakdown, the long-term fitness consequences of interpopulation hybridization are surprisingly benign.

  4. No evidence for faster male hybrid sterility in population crosses of an intertidal copepod (Tigriopus californicus).

    Science.gov (United States)

    Willett, Christopher S

    2008-06-01

    Two different forces are thought to contribute to the rapid accumulation of hybrid male sterility that has been observed in many inter-specific crosses, namely the faster male and the dominance theories. For male heterogametic taxa, both faster male and dominance would work in the same direction to cause the rapid evolution of male sterility; however, for taxa lacking differentiated sex chromosomes only the faster male theory would explain the rapid evolution of male hybrid sterility. It is currently unknown what causes the faster evolution of male sterility, but increased sexual selection on males and the sensitivity of genes involved in male reproduction are two hypotheses that could explain the observation. Here, patterns of hybrid sterility in crosses of genetically divergent copepod populations are examined to test potential mechanisms of faster male evolution. The study species, Tigriopus californicus, lacks differentiated, hemizygous sex chromosomes and appears to have low levels of divergence caused by sexual selection acting upon males. Hybrid sterility does not accumulate more rapidly in males than females in these crosses suggesting that in this taxon male reproductive genes are not inherently more prone to disruption in hybrids.

  5. Genetic consequences of many generations of hybridization between divergent copepod populations.

    Science.gov (United States)

    Edmands, S; Feaman, H V; Harrison, J S; Timmerman, C C

    2005-01-01

    Crosses between populations of the copepod Tigriopus californicus typically result in outbreeding depression. In this study, replicate hybrid populations were initiated with first generation backcross hybrids between two genetically distinct populations from California: Royal Palms (RP) and San Diego (SD). Reciprocal F(1) were backcrossed to SD, resulting in expected starting frequencies of 25% RP/75% SD nuclear genes on either a pure RP cytoplasmic or a pure SD cytoplasmic background. After 1 year of hybridization (up to 15 generations), seven microsatellite loci were scored in two replicates on each cytoplasmic background. Frequencies of the rarer RP alleles increased significantly in all four replicates, regardless of cytoplasmic source, producing a mean hybridity of 0.97 (maximum = 1), instead of the expected 0.50. Explicit tests for heterozygote excess across loci and replicates showed significant deviations. Only the two physically linked markers showed linkage disequilibrium in all replicates. Subsequent fitness assays in parental populations and early generation hybrids revealed lower fitness in RP than SD, and significant F(2) breakdown. Computer simulations showed that selection must be invoked to explain the shift in allele frequencies. Together, these results suggest that hybrid inferiority in early generations gave way to hybrid superiority in later generations.

  6. Isolation and characterization of cytochrome c from the marine copepod Tigriopus californicus.

    Science.gov (United States)

    Rawson, P D; Brazeau, D A; Burton, R S

    2000-05-02

    Mitochondrial energy production requires complex interactions among proteins encoded in both the nuclear and mitochondrial genomes. The intergenomic coevolution of interacting gene products has been previously suggested based on interspecific comparisons of cytochrome c (encoded by the nuclear CYC gene) and cytochrome c oxidase (partly encoded in the mitochondrial DNA by the COX1, COX2 and COX3 genes). In the intertidal copepod, Tigriopus californicus, non-synonymous substitutions in the COX1 gene have previously been found in interpopulation comparisons. In order to determine if CYC also shows interpopulation variation, this gene was isolated from a cDNA library using a degenerate primer/polymerase chain reaction approach. Characterization of a cDNA sequence and 25 genomic DNA sequences derived from four T. californicus populations yielded the following results: (1) the T. californicus CYC gene is interrupted by an intron that occurs at the same position as the intron found in vertebrate CYC genes; (2) there is extensive sequence variation within both the coding region and intron of this gene and the vast majority of this variation occurs between sequences drawn from geographically distinct populations; (3) the coding sequence variation includes a minimum of five amino acid replacement substitutions; (4) segregation of length variants among offspring in an interpopulation cross revealed genotypic ratios consistent with the proposed allelic nature of the CYC variants. These results demonstrate that the requisite genetic variation required for intergenomic coevolution exists in the CYC-COX system in T. californicus.

  7. Acclimation and adaptation to common marine pollutants in the copepod Tigriopus californicus.

    Science.gov (United States)

    Sun, Patrick Y; Foley, Helen B; Handschumacher, Lisa; Suzuki, Amanda; Karamanukyan, Tigran; Edmands, Suzanne

    2014-10-01

    Establishing water quality criteria using bioassays is complicated by variation in chemical tolerance between populations. Two major contributors to this variation are acclimation and adaptation, which are both linked to exposure history, but differ in how long their effects are maintained. Our study examines how tolerance changes over multiple generations of exposure to two common marine pollutants, copper (Cu) and tributyltin oxide (TBTO), in a sexually reproducing marine copepod, Tigriopus californicus. Lines of T. californicus were chronically exposed to sub-lethal levels of Cu and TBTO for 12 generations followed by a recovery period of 3 generations in seawater control conditions. At each generation, the average number of offspring produced and survived to 28 d was determined and used as the metric of tolerance. Lines exposed to Cu and TBTO showed an overall increase in tolerance over time. Increased Cu tolerance arose by generation 3 in the chronically exposed lines and was lost after 3 generations in seawater control conditions. Increased TBTO tolerance was detected at generation 7 and was maintained even after 3 generations in seawater control conditions. It was concluded from this study that tolerance to Cu is consistent with acclimation, a quick gain and loss of tolerance. In contrast, TBTO tolerance is consistent with adaptation, in which onset of tolerance was delayed relative to an acclimation response and maintained in the absence of exposure. These findings illustrate that consideration of exposure history is necessary when using bioassays to measure chemical tolerance.

  8. Molecular and quantitative trait variation within and among populations of the intertidal copepod Tigriopus californicus.

    Science.gov (United States)

    Edmands, Suzanne; Harrison, J Scott

    2003-10-01

    While molecular and quantitative trait variation may be theoretically correlated, empirical studies using both approaches frequently reveal discordant patterns, and these discrepancies can contribute to our understanding of evolutionary processes. Here, we assessed genetic variation in six populations of the copepod Tigriopus californicus. Molecular variation was estimated using five polymorphic microsatellite loci, and quantitative variation was measured using 22-life history and morphometric characters. Within populations, no correlation was found between the levels of molecular variation (heterozygosity) and quantitative variation (heritability). Between populations, quantitative subdivision (Q(ST)) was correlated with molecular subdivision when measured as F(ST) but not when measured as R(ST). Unlike most taxa studied to date, the overall level of molecular subdivision exceeded the level of quantitative subdivision (F(ST) = 0.80, R(ST) = 0.89, Q(ST) = 0.30). Factors that could contribute to this pattern include stabilizing or fluctuating selection on quantitative traits or accelerated rates of molecular evolution.

  9. Proline biosynthesis genes and their regulation under salinity stress in the euryhaline copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S; Burton, Ronald S

    2002-08-01

    Diverse organisms regulate concentrations of intracellular organic osmolytes in response to changes in environmental salinity or desiccation. In marine crustaceans, accumulation of high concentrations of proline is a dominant component of response to hyperosmotic stress. In the euryhaline copepod Tigriopus californicus, synthesis of proline from its metabolic precursor glutamate is tightly regulated by changes in environmental salinity. Here, for the first time in a marine invertebrate, the genes responsible for this pathway have been cloned and characterized. The two proteins display the sequence features of homologous enzymes identified from other eukaryotes. One of the cloned genes, delta1-pyrroline-5-carboxylase reductase (P5CR), is demonstrated to have the reductase enzyme activity when expressed in proline-auxotroph bacteria, while the second, delta1-pyrroline-5-carboxylase synthase (P5CS), does not rescue proline-auxotroph bacteria. In contrast to results from higher plants, neither levels of P5CS nor P5CR mRNAs increase in response to salinity stress in T. californicus. Hence, regulation of proline synthesis during osmotic stress in T. californicus is likely mediated by some form of post-transcriptional regulation of either P5CS or P5CR. Understanding the regulation this pathway may elucidate the mechanisms limiting the salinity ranges of marine taxa.

  10. Maladapted gene complexes within populations of the intertidal copepod Tigriopus californicus?

    Science.gov (United States)

    Edmands, Suzanne; Northrup, Sara L; Hwang, Annmarie S

    2009-08-01

    The prevalence of F2 hybrid breakdown in interpopulation crosses of the marine copepod Tigriopus californicus can be explained by disruption of coadapted gene complexes. This study further dissects the nature of hybrid gene interactions, revealing that parental populations may also harbor maladapted gene complexes. Diagnostic molecular markers (14) were assayed in reciprocal F2 hybrids to test for gene interactions affecting viability. Results showed some evidence of nuclear-nuclear coadaptation. Although there were no significant examples of pairwise linkage disequilibrium between physically unlinked loci, one of the two reciprocal crosses did show an overall excess of parental double homozygotes and an overall dearth of nonparental double homozygotes. In contrast, the nuclear-cytoplasmic data showed a stronger tendency toward maladaptation within the specific inbred lines used in this study. For three out of four loci with significant frequency differences between reciprocal F2, homozygotes were favored on the wrong cytoplasmic background. A separate study of reciprocal backcross hybrids between the same two populations (but different inbred lines) revealed faster development time when the full haploid nuclear genome did not match the cytoplasm. The occurrence of such suboptimal gene complexes may be attributable to effects of genetic drift in small, isolated populations.

  11. Zooplankton community structure and copepod species composition in the northern Gulf of Mexico

    Science.gov (United States)

    Ortner, Peter B.; Hill, Leonard C.; Cummings, Shailer R.

    1989-04-01

    Zooplankton community structure and copepod species composition are analysed in samples obtained during spring and winter from three areas of the northern Gulf of Mexico: near the Mississippi River outflow, off Cape San Blas, and in the central Gulf of Mexico. Samples from different regions were distinguishable in correspondence analysis of dominant species and/or functional groups. The near-surface communities of the Mississippi and central Gulf were particularly distinct while Cape San Blas was intermediate in both structure and specific character. Saltier waters directly beneath the Mississippi Plume yielded samples similar to those from near-surface waters well offshore. At the same time near-surface waters off the Mississippi and off Cape San Blass to the west were distinguishable even during spring when the outflow from the Mississippi was at its annual peak. These differences are consistent with the discharge and flow patterns of the Mississippi River plume and the northern Gulf and with systematic differences in such parameters as temperature, salinity and chlorophyll concentration. The implications of these observations upon the feeding environments of the larvae of commercially significant fish species are addressed since both zooplankton prey and larval predators appear to be particularly abundant in the Mississippi River plume environs.

  12. The complete mitochondrial genome of the cyclopoid copepod Paracyclopina nana: a highly divergent genome with novel gene order and atypical gene numbers.

    Science.gov (United States)

    Ki, Jang-Seu; Park, Heum Gi; Lee, Jae-Seong

    2009-04-15

    In this paper, we describe the complete mitogenome of the cyclopoid copepod Paracyclopina nana with emphasis on the highly rearranged gene order and high divergence against published copepod mitogenomes. The P. nana mtDNA is 15,981 bp in length (70.9% AT) and consists of 37 genes (12 protein-coding genes, 2 rRNAs, 23 tRNAs) that are atypical for metazoan mitogenomes. Unusually, it contains an extra tRNA (tRNA-Ala) but it does not contain the ATPase 8 gene. The P. nana mitogenome has a long putative control region with high AT content (1351 bp, 77.0% AT). The Cyt b was considerably short in length, compared to other crustaceans. Compared to typical mitogenomes of arthropods and copepods, the gene order of the P. nana mitogenome is highly rearranged with a novel gene structure. In addition, P. nana has highly divergent mt genes (mostly less than 50%), judged by amino acid substitution. We present the first complete mitogenome sequence from a cyclopoid copepod, thereby increasing our understanding of copepod and crustacean evolution from the mitochondrial point of view.

  13. Linking climate change to community-level impacts on copepods via a new, trait-based model: Life-history and metabolic mechanisms compared

    DEFF Research Database (Denmark)

    Banas, Neil S.; Møller, Eva Friis; Nielsen, Torkel Gissel;

    A new, trait-based copepod model ("Coltrane": Copepod Life-history Traits and Adaptation to Novel Environments) has been developed, drawing on past work on both optimal annual routines and trait-based plankton metacommunity models, in order to evaluate climate impacts on copepods via 1) phenology...... and life history and 2) temperature and energy budgets in a unified framework. In an idealized global-scale testbed, the model correctly predicts life strategies in large Calanus spp. ranging from multiple generations per year to multiple years per generation. In a Bering Sea testbed, the model replicates...... the dramatic variability in the abundance of C. glacialis/marshallae observed between warm and cold years of the 2000s, and indicates (consistent with recent field studies) that sea ice-linked prey phenology is a more important driver than temperature per se. In a Disko Bay, West Greenland testbed, the model...

  14. Laboratory and field efficacy of Pedalium murex and predatory copepod, Mesocyclops longisetus on rural malaria vector, Anopheles culicifacies

    Science.gov (United States)

    Chitra, Thangadurai; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Madhiyazhagan, Pari; Nataraj, Thiyagarajan; Indumathi, Duraisamy; Hwang, Jiang-Shiou

    2013-01-01

    Objective To test the potentiality of the leaf extract of Pedalium murex (P. murex) and predatory copepod Mesocyclops longisetus (M. longisetus) in individual and combination in controlling the rural malarial vector, Anopheles culicifacies (An. culicifacies) in laboratory and field studies. Methods P. murex leaves were collected from in and around Erode, Tamilnadu, India. The active compounds were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. Laboratory studies on larvicidal and pupicidal effects of methanolic extract of P. murex tested against the rural malarial vector, An. culicifacies were significant. Results Evaluated lethal concentrations (LC50) of P. murex extract were 2.68, 3.60, 4.50, 6.44 and 7.60 mg/L for I, II, III, IV and pupae of An. culicifacies, respectively. Predatory copepod, M. longisetus was examined for their predatory efficacy against the malarial vector, An. culicifacies. M. longisetus showed effective predation on the early instar (47% and 36% on I and II instar) when compared with the later ones (3% and 1% on III and IV instar). Predatory efficacy of M. longisetus was increased (70% and 45% on I and II instar) when the application was along with the P. murex extract. Conclusions Predator survival test showed that the methanolic extract of P. murex is non-toxic to the predatory copepod, M. longisetus. Experiments were also conducted to evaluate the efficacy of methanolic extract of P. murex and M. longisetus in the direct breeding sites (paddy fields) of An. culicifacies. Reduction in larval density was very high and sustained for a long time in combined treatment of P. murex and M. longisetus.

  15. Spatiotemporal distribution of protozooplankton and copepod nauplii in relation to the occurrence of giant jellyfish in the Yellow Sea

    Science.gov (United States)

    Wang, Lu; Xu, Kuidong

    2013-11-01

    The occurrence of the giant jellyfish, Nemopilema nomurai, has been a frequent phenomenon in the Yellow Sea. However, the relationship between the giant jellyfish and protozoa, in particular ciliates, remains largely unknown. We investigated the distribution of nanoflagellates, ciliates, Noctiluca scintillans, and copepod nauplii along the transect 33°N in the Yellow Sea in June and August, 2012, during an occurrence of the giant jellyfish, and in October of that year when the jellyfish was absent. The organisms studied were mainly concentrated in the surface waters in summer, while in autumn they were evenly distributed in the water column. Nanoflagellate, ciliate, and copepod nauplii biomasses increased from early June to August along with jellyfish growth, the first two decreased in October, while N. scintillans biomass peaked in early June to 3 571 μg C/L and decreased in August and October. In summer, ciliate biomass greatly exceeded that of copepod nauplii (4.61-15.04 μg C/L vs. 0.34-0.89 μg C/L). Ciliate production was even more important than biomass, ranging from 6.59 to 34.19 μg C/(L·d) in summer. Our data suggest a tight and positive association among the nano-, micro-, and meso-zooplankton in the study area. Statistical analysis revealed that the abundance and total production of ciliate as well as loricate ciliate biomass were positively correlated with giant jellyfish biomass, indicating a possible predator-prey relationship between ciliates and giant jellyfish. This is in contrast to a previous study, which reported a significant reduction in ciliate standing crops due to the mass occurrence of N. nomurai in summer. Our study indicates that, with its high biomass and, in particular, high production ciliates might support the mass occurrence of giant jellyfish.

  16. Adverse effects of MWCNTs on life parameters, antioxidant systems, and activation of MAPK signaling pathways in the copepod Paracyclopina nana.

    Science.gov (United States)

    Kim, Duck-Hyun; Puthumana, Jayesh; Kang, Hye-Min; Lee, Min-Chul; Jeong, Chang-Bum; Han, Jeonghoon; Hwang, Dae-Sik; Kim, Il-Chan; Lee, Jin Wuk; Lee, Jae-Seong

    2016-10-01

    Engineered multi-walled carbon nanotubes (MWCNTs) have received widespread applications in a broad variety of commercial products due to low production cost. Despite their significant commercial applications, CNTs are being discharged to aquatic ecosystem, leading a threat to aquatic life. Thus, we investigated the adverse effect of CNTs on the marine copepod Paracyclopina nana. Additional to the study on the uptake of CNTs and acute toxicity, adverse effects on life parameters (e.g. growth, fecundity, and size) were analyzed in response to various concentrations of CNTs. Also, as a measurement of cellular damage, oxidative stress-related markers were examined in a time-dependent manner. Moreover, activation of redox-sensitive mitogen-activated protein kinase (MAPK) signaling pathways along with the phosphorylation pattern of extracellular signal-regulated kinase (ERK), p38, and c-Jun-N-terminal kinases (JNK) were analyzed to obtain a better understanding of molecular mechanism of oxidative stress-induced toxicity in the copepod P. nana. As a result, significant inhibition on life parameters and evoked antioxidant systems were observed without ROS induction. In addition, CNTs activated MAPK signaling pathway via ERK, suggesting that phosphorylated ERK (p-ERK)-mediated adverse effects are the primary cause of in vitro and in vivo endpoints in response to CNTs exposure. Moreover, ROS-independent activation of MAPK signaling pathway was observed. These findings will provide a better understanding of the mode of action of CNTs on the copepod P. nana at cellular and molecular level and insight on possible ecotoxicological implications in the marine environment.

  17. Seasonal changes in food quantity and quality of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus: a bioassay approach

    DEFF Research Database (Denmark)

    Koski, Marja; Dutz, Jörg; Klein Breteler, W.;

    2010-01-01

    We evaluated the food quantity and quality over a seasonal cycle for the development and egg production of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus, using a bioassay approach. Seston was sampled from December to October from a well-mixed water column of the Mar......We evaluated the food quantity and quality over a seasonal cycle for the development and egg production of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus, using a bioassay approach. Seston was sampled from December to October from a well-mixed water column...

  18. Role of essential lipids in copepod nutrition: no evidence for trophic upgrading of food quality by a marine ciliate

    DEFF Research Database (Denmark)

    Klein Breteler, W.; Koski, Marja; Rampen, S.

    2004-01-01

    copepod species consumed S. sulcatum at significant rates, but after 3 d, weight-specific ingestion decreased more than 2-fold. Larvae and copepodites feeding on S. sulcatum developed at suboptimal rates, survived poorly and showed abnormal morphology in comparison to control individuals fed a good......., although in low abundance of unuseful Delta7 sterols. Obviously, S. sulcatum did not biochemically enhance bacterial or algal food for subsequent use at higher trophic levels, and only transferred fatty acids without further conversion. The results indicate a deficiency in the ciliate of HUFAs and sterols...

  19. Ingestion rate and gut clearance in the planktonic copepod Centropages hamatus in relation to food concentration and temperature

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Møhlenberg, F.; Nicolajsen, Hanne

    1982-01-01

    .degree. C. Within the temperature interval studied (1.degree.-15.degree. C), maximum ingestion rate increased with temperature with a Q10 of 3.9. Gut clearance was estimated by following the exponential decrease in the gut content of plant pigments (measured fluorimetrically) with time after feeding...... be considered an estimate of ingestion rate, yielded values similar to ingestion rates actually measured. This implies that in situ algal ingestion rates may be estimated from measurements of the content of plant pigments in the guts of freshly caught copepods....

  20. Effects of three PBDEs on development, reproduction and population growth rate of the harpacticoid copepod Nitocra spinipes

    DEFF Research Database (Denmark)

    Breitholtz, M.; Wollenberger, Leah

    2003-01-01

    The current knowledge concerning effects of polybrominated diphenyl ethers (PBDEs) on aquatic organisms is very limited. A full life-cycle (less than or equal to 26 days exposure) ecotoxicity test with the particle-feeding copepod Nitocra spinipes was therefore used to study effects of BDE-47, -99...... to the controls (***P PBDEs...... and that ingestion of particle-adsorbed PBDEs most likely is the predominant route of exposure in N. spinipes. However, to further improve the usefulness of laboratory effect levels of PBDEs and other lipophilic substances for environmental risk assessment, it is important to develop ecotoxicological tools, which...

  1. Evolution of interacting proteins in the mitochondrial electron transport system in a marine copepod.

    Science.gov (United States)

    Willett, Christopher S; Burton, Ronald S

    2004-03-01

    The extensive interaction between mitochondrial-encoded and nuclear-encoded subunits of electron transport system (ETS) enzymes in mitochondria is expected to lead to intergenomic coadaptation. Whether this coadaptation results from adaptation to the environment or from fixation of deleterious mtDNA mutations followed by compensatory nuclear gene evolution is unknown. The intertidal copepod Tigriopus californicus shows extreme divergence in mtDNA sequence and provides an excellent model system for study of intergenomic coadaptation. Here, we examine genes encoding subunits of complex III of the ETS, including the mtDNA-encoded cytochrome b (CYTB), the nuclear-encoded rieske iron-sulfur protein (RISP), and cytochrome c(1) (CYC1). We compare levels of polymorphism within populations and divergence between populations in these genes to begin to untangle the selective forces that have shaped evolution in these genes. CYTB displays dramatic divergence between populations, but sequence analysis shows no evidence for positive selection driving this divergence. CYC1 and RISP have lower levels of sequence divergence between populations than CYTB, but, again, sequence analysis gives no evidence for positive selection acting on them. However, an examination of variation at cytochrome c (CYC), a nuclear-encoded protein that transfers electrons between complex III and complex IV provides evidence for selective divergence. Hence, it appears that rapid evolution in mitochondrial-encoded subunits is not always associated with rapid divergence in interacting subunits (CYC1 and RISP), but can be in some cases (CYC). Finally, a comparison of nuclear-encoded and mitochondrial-encoded genes from T. californicus suggests that substitution rates in the mitochondrial-encoded genes are dramatically increased relative to nuclear genes.

  2. Interpopulation patterns of divergence and selection across the transcriptome of the copepod Tigriopus californicus.

    Science.gov (United States)

    Barreto, Felipe S; Moy, Gary W; Burton, Ronald S

    2011-02-01

    The accumulation of genetic incompatibilities between isolated populations is thought to lead to the evolution of intrinsic postzygotic isolation. The molecular basis for these mechanisms, however, remains poorly understood. The intertidal copepod Tigriopus californicus provides unique opportunities for addressing mechanistic questions regarding the early stages of speciation; hybrids between highly divergent populations are fertile and viable, but exhibit reduced fitness at the F(2) or later generations. Given the current scarcity of genomic information in taxa at incipient stages of reproductive isolation, we utilize high-throughout 454 pyrosequencing to characterize a substantial fraction of protein-coding regions (the transcriptome) of T. californicus. Our sequencing effort was divided equally between two divergent populations in order to estimate levels of divergence and to reveal patterns of selection across the transcriptome. Assembly of sequences generated over 40,000 putatively unique transcripts (unigenes) for each population, 19,622 of which were orthologous between populations. BLAST searches of public databases determined protein identity and functional features for 15,402 and 12,670 unigenes, respectively. Based on rates of nonsynonymous and synonymous substitutions in 5897 interpopulation orthologs (those >150 bp and with at least 2X coverage), we identified 229 potential targets of positive selection. Many of these genes are predicted to be involved in several metabolic processes, and to function in hydrolase, peptidase and binding activities. The library of T. californicus coding regions, annotated with their predicted functions and level of divergence, will serve as an invaluable resource for elucidating molecular mechanisms underlying the early stages of speciation.

  3. Unusual structure of ribosomal DNA in the copepod Tigriopus californicus: intergenic spacer sequences lack internal subrepeats.

    Science.gov (United States)

    Burton, R S; Metz, E C; Flowers, J M; Willett, C S

    2005-01-03

    Eukaryotic nuclear ribosomal DNA (rDNA) is typically arranged as a series of tandem repeats coding for 18S, 5.8S, and 28S ribosomal RNAs. Transcription of rDNA repeats is initiated in the intergenic spacer (IGS) region upstream of the 18S gene. The IGS region itself typically consists of a set of subrepeats that function as transcriptional enhancers. Two important evolutionary forces have been proposed to act on the IGS region: first, selection may favor changes in the number of subrepeats that adaptively adjust rates of rDNA transcription, and second, coevolution of IGS sequence with RNA polymerase I transcription factors may lead to species specificity of the rDNA transcription machinery. To investigate the potential role of these forces on population differentiation and hybrid breakdown in the intertidal copepod Tigriopus californicus, we have characterized the rDNA of five T. californicus populations from the Pacific Coast of North America and one sample of T. brevicornicus from Scotland. Major findings are as follows: (1) the structural genes for 18S and 28S are highly conserved across T. californicus populations, in contrast to other nuclear and mitochondrial DNA (mtDNA) genes previously studied in these populations. (2) There is extensive differentiation among populations in the IGS region; in the extreme, no homology is observed across the IGS sequences (>2 kb) from the two Tigriopus species. (3) None of the Tigriopus IGS sequences have the subrepeat structure common to other eukaryotic IGS regions. (4) Segregation of rDNA in laboratory crosses indicates that rDNA is located on at least two separate chromosomes in T. californicus. These data suggest that although IGS length polymorphism does not appear to play the adaptive role hypothesized in some other eukaryotic systems, sequence divergence in the rDNA promoter region within the IGS could lead to population specificity of transcription in hybrids.

  4. Three divergent mitochondrial genomes from California populations of the copepod Tigriopus californicus.

    Science.gov (United States)

    Burton, Ronald S; Byrne, Rosemary J; Rawson, Paul D

    2007-11-15

    Previous work on the harpacticoid copepod Tigriopus californicus has focused on the extensive population differentiation in three mtDNA protein coding genes (COXI, COXII, Cytb). In order to get a more complete understanding of mtDNA evolution in this species, we sequenced three complete mitochondrial genomes (one from each of three California populations) and compared them to two published mtDNA genomes from an Asian congener, Tigriopus japonicus. Several features of the mtDNA genome appear to be conserved within the genus: 1) the unique order of the protein coding genes, rRNA genes and most of the tRNA genes, 2) the genome is compact, varying between 14.3 and 14.6 kb, and 3) all genes are encoded on the same strand of the mtDNA. Within T. californicus, extremely high levels of nucleotide divergence (>20%) are observed across much of the mitochondrial genome. Inferred amino acid sequences of the proteins encoded in the mtDNAs also show high levels of divergence; at the extreme, the three ND3 variants in T. californicus showed >25% amino acid substitutions, compared with californicus mtDNAs. Although not previously noted, this feature is also conserved in T. japonicus mtDNAs; whether this sequence is processed into a functional tRNA has not been determined. The putative control region contains a duplicated segment of different length (from 88 to 155 bp) in each of the T. californicus sequences. In each case, the duplicated segments are not tandem repeats; despite their different lengths, the distance between the start of the first and the start of the second repeat is conserved (520 bp). The functional significance, if any, of this repeat structure remains unknown.

  5. Mating behaviours of Daphnia pulicaria, a cyclic parthenogen: comparisons with copepods

    Science.gov (United States)

    Brewer, M. C.

    1998-01-01

    The pre-and post-contact mating behaviours of Daphnia pulicaria are investigated by direct observations of vertical distributions, swimming behaviours and male-female interactions. Analysis of vertical distributions in a 1 m deep, thermally stratified migration chamber reveals that females were always located in the upper layer of the water column but males exhibited a bimodal depth distribution, in which an individual's depth was a function of body length and water temperature. The observed distributions of males may be the result of several interacting pressures; predation avoidance, life-history optimization, and avoidance of assortative mating. Male swimming behaviour was faster and orthogonal to that of females, which is in agreement with the predictions of encounter-rate maximization models. Video recordings of males and females interacting in a 1-litre vessel showed that males both pursued and contacted other males more often than females. Thus, there was no evidence that Daphnia are able to use water-borne chemical signals to locate and identify potential mates. However, the average duration of male-female contacts (13.8 s) was much longer than those between males (1.6 s), suggesting that males can determine the sex of contacted individuals.Daphnia mating behaviour is significantly more complex than previously acknowledged. In contrast to the conventional view of Daphnia males swimming more-or-less randomly and mating with any individual encountered, they exhibit behaviours which increase the potential of mating with females while reducing the risk of predation. Several male behaviours, such as 'scanning' and the performance of area-restricted spirals upon encounter, are similar to those reported for some copepods and may be common to zooplankton that lack sophisticated chemosensory abilities. The possibility that Daphnia may also be able to assess such important female attributes as species and reproductive status is discussed.

  6. Alien parasitic copepods in mussels and oysters of the Wadden Sea

    Science.gov (United States)

    Elsner, Nikolaus O.; Jacobsen, Sabine; Thieltges, David W.; Reise, Karsten

    2011-09-01

    Molluscan intestinal parasites of the genus Mytilicola, specifically M. intestinalis, were initially introduced into bivalves in the North Sea in the 1930s. It was presumably introduced from the Mediterranean with ship-fouling mussels, then attained epidemic proportions in Mytilus edulis in the 1950s and is now widely established in the North Sea region. Mytilicola orientalis was co-introduced with Pacific oysters to France in the 1970s and in the southern North Sea in the early 1990s. Its main host Crassostrea gigas has massively invaded the Wadden Sea with a concomitant decline in mussels. To explore whether introduced mytilicolid parasites could play a role in the shifting dominance from native mussels to invasive oysters, we analysed 390 mussels and 174 oysters collected around the island of Sylt in the northern Wadden Sea. We show that M. intestinalis has a prevalence >90% and a mean intensity of 4 adult copepods in individual mussels with >50 mm shell length at all sheltered sites. By contrast, none were found in the oysters. However, at one site, we found M. orientalis in C. gigas with a prevalence of 10% and an intensity of 2 per host individual (August 2008). This constitutes the most northern record in Europe for this Pacific parasite until now. Alignments of partial sequences of the mitochondrial cytochrome oxidase I (COI) gene and the nuclear internal transcribed spacers (ITS) and 18S rDNA sequences each show a distinct difference between the two species, which confirms our morphological identification. We suggest that the high parasite load in mussels compared to oysters may benefit the continued expansion of C. gigas in the Wadden Sea.

  7. Habitat usage by the cryptic copepods Pseudocalanus moultoni and P. newmani on Georges Bank (Northwest Atlantic)

    Science.gov (United States)

    Bucklin, Ann; McGillicuddy, Dennis J.; Wiebe, Peter H.; Davis, Cabell S.

    2015-12-01

    The cryptic copepod species, Pseudocalanus moultoni and P. newmani, co-occur on Georges Bank and in the Gulf of Maine (Northwest Atlantic); even recent studies have reported results and conclusions based on examination of the combined species. Species-specific PCR (SS-PCR) based on mitochondrial cytochrome oxidase I (COI) sequence divergence was used in this study to discriminate the species. Species-specific descriptions of habitat usage and predicted patterns of transport and retention on Georges Bank were made by mapping distributions and calculating abundances of each species from January to June, 1999 for four vertical strata (0-15 m, 15-40 m, 40-100 m, and 0-100 m) and five regions (Northern Flank, Bank Crest, Northeast Peak, Southern Flank, and Slope Water) identified on the basis of bathymetry and circulation. Patterns of distribution and abundance for the two species during January to June, 1999 were largely consistent with those described based on vertically integrating mapping and analysis for the same period in 1997 by McGillicuddy and Bucklin (2002). The region-specific and depth-stratified analyses allowed further discrimination in habitat usage by the species and confirmed the distinctive patterns for the two species. The observed differences between the species in abundances among the five regions and three depth strata over Georges Bank impact their transport trajectories. The concentration of P. moultoni in deep layers likely explains the higher rates of retention and lower rates of advective loss of this species from the Bank, compared to P. newmani, which may be more subject to wind-driven transport in the surface layer. Accurate identification and discrimination of even closely-related and cryptic species is needed to ensure full understanding and realistic predictions of changes in diversity of zooplankton and the functioning of pelagic ecosystems.

  8. Prey capture of pike Esox lucius larvae in turbid water.

    Science.gov (United States)

    Salonen, M; Engström-Ost, J

    2010-06-01

    Pike Esox lucius larvae captured fewer calanoid and cyclopoid copepods in turbid than in clear water, whereas no differences were detected in feeding rates on Daphnia longispina. Decreased capture of copepods may lead to lower growth and survival of E. lucius larvae in turbid areas, in particular, if cladocerans are scarce.

  9. Physiological effects of an allozyme polymorphism: glutamate-pyruvate transaminase and response to hyperosmotic stress in the copepod Tigriopus californicus.

    Science.gov (United States)

    Burton, R S; Feldman, M W

    1983-04-01

    In order to regulate cell volume during hyperosmotic stress, the intertidal copepod Tigriopus californicus, like other aquatic crustaceans, rapidly accumulates high levels of intracellular alanine, proline, and glycine. Glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), which catalyzes the final step of alanine synthesis, is genetically polymorphic in T. californicus populations at Santa Cruz, California. Spectrophotometric studies of homogenates derived from a homozygous isofemale line of each of the two common GPT alleles indicated that the GPTF allozyme has a significantly higher specific activity than the GPTS allozyme. Under conditions of hyperosmotic stress, individual adult copepods of GPTF and GPTF/S genotypes accumulated alanine, but not glycine or proline, more rapidly than GPTS homozygotes. When young larvae were subjected to the same hyperosmotic conditions, GPTS larvae suffered a significantly higher mortality than GPTF or GPTF/S larvae. These results suggest that the biochemical differences among GPT allozymes result in specific physiological variation among GPT genotypes and that this physiological variation is manifested in differential genotypic survivorships under some naturally occurring environmental conditions.

  10. Morphology and pathology of the ectoparasitic copepod, Nicothoë astaci ('lobster louse') in the European lobster, Homarus gammarus.

    Science.gov (United States)

    Wootton, Emma C; Pope, Edward C; Vogan, Claire L; Roberts, Emily C; Davies, Charlotte E; Rowley, Andrew F

    2011-09-01

    Ectoparasitic copepods have been reported in a wide range of aquatic animals, including crustacean shellfish. However, with the exception of the salmon louse, Lepeophtheirus salmonis, our knowledge of such parasites in commercial species is rudimentary. The current study examines the morphology and pathology of the parasitic copepod, Nicothoë astaci (the 'lobster louse') in its host, the European lobster, Homarus gammarus. Lobsters were sampled from waters surrounding Lundy Island (Bristol Channel, UK) and all individuals collected were found to harbour female adult N. astaci in their gills, with a mean of 47·3 parasites/lobster. The majority of N. astaci were found in the basal region of pleurobranch gills. The parasite was found to attach to gill filaments via its oral sucker, maxillae and maxillipeds, and to feed on host haemolymph (blood) through a funnel-like feeding channel. It caused varying degrees of damage to the host gill, including occlusion of gill filaments and disruption to the vascular system in the central axis. Although there was evidence of extensive host response (haemocytic infiltration) to the parasite, it was displaced from the parasite attachment site and thus was observed in the central gill axis below. The region of gill filament immediately underlying the parasite feeding channel was devoid of such activity suggesting that the parasite interferes with the cellular defence and haemostatic mechanisms of the lobster in order to maintain invasion of the host.

  11. Crude oil affecting the biomass of the marine copepod Calanus finmarchicus: Comparing a simple and complex population model.

    Science.gov (United States)

    De Hoop, Lisette; Broch, Ole Jacob; Hendriks, A Jan; De Laender, Frederik

    2016-08-01

    In the current study differences were evaluated between a complex 3D multistage population model (SINMOD) and a simpler consumer-resource population model for estimating the effects of crude oil on the marine copepod Calanus finmarchicus. The SINTEF OSCAR model was used to simulate hypothetical oil spills in the Lofoten area in 1995, 1997, and 2001. Both population models simulated a negligible effect of crude oil on the Calanus' biomass when assuming low species sensitivity. The simple model estimated a larger effect on the biomass (up to a 100% decline) compared to the complex model (maximum decline of 60-80%) at high species sensitivity to crude oil. These differences may be related to the inclusion of copepod advection in the complex model. Our study showed that if little data is available to parameterize a model, or if computational resources are scarce, the simple model could be used for risk screening. Nevertheless, the possibility of including a dilution factor for time-varying biomass should be examined to improve the estimations of the simple model. The complex model should be used for a more in depth risk analysis, as it includes physical processes such as the drift of organisms and differentiation between developmental stages.

  12. Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity

    Directory of Open Access Journals (Sweden)

    Kevin R. Carman

    2012-04-01

    Full Text Available High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal. Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC50 values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers.

  13. Dietary carotenoids regulate astaxanthin content of copepods and modulate their susceptibility to UV light and copper toxicity.

    Science.gov (United States)

    Caramujo, Maria-José; de Carvalho, Carla C C R; Silva, Soraya J; Carman, Kevin R

    2012-05-01

    High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC(50) values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers.

  14. Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to Zostera noltii beds

    Science.gov (United States)

    Vafeiadou, A.-M.; Materatski, P.; Adão, H.; De Troch, M.; Moens, T.

    2014-07-01

    This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos and/or epiphytes are among the main resources of most taxa, but seagrass detritus and sediment particulate organic matter contribute as well to meiobenthos nutrition, which are also available in deeper sediment layers and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that the interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

  15. Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to Zostera noltii beds

    Directory of Open Access Journals (Sweden)

    A.-M. Vafeiadou

    2014-01-01

    Full Text Available This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments, using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos is among the main resources of most taxa, but seagrass-associated resources (i.e. seagrass detritus and epiphytes also contribute to meiobenthos nutrition, with seagrass detritus being available also in deeper sediments and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

  16. Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

    NARCIS (Netherlands)

    Plum, C.; Gollner, S.; Martinez Arbizu, P.; Bright, M.

    2015-01-01

    In order to characterize the copepod communitiesassociated with tubeworm and mussel aggregations around ahydrocarbon seep in the Green Canyon of the Gulf of Mexico,diversity, abundance, and community composition were analyzed.Also analyzed were species biogeography and the potentialconnectivity to o

  17. Algal grazing by the planktonic copepods Centropages hamatus and Pseudocalanus sp.: Diurnal and seasonal variation during the spring phytoplankton bloom in the Øresund Denmark

    DEFF Research Database (Denmark)

    Nicolajsen, Hanne; Møhlenberg, Flemming; Kiørboe, Thomas

    1983-01-01

    Seasonal and diel variation in rate of algal grazing were estimated from measurements of gut content (plant pigments) and gut turnover in the copepods C. hamatus and Pseudocalanus sp. during spring (Jan.-May) in the Oresund. Both species exhibited significant diel variation in gut content...

  18. Extensive genetic diversity and endemism across the global range of the oceanic copepod Pleuromamma abdominalis

    Science.gov (United States)

    Hirai, Junya; Tsuda, Atsushi; Goetze, Erica

    2015-11-01

    Many oceanic zooplankton species have been described as cosmopolitan in distribution; however, recent molecular work has detected species complexity with highly divergent genetic lineages within several of these taxa. To further resolve the species complexity within these ecologically-important and widespread species, we performed both molecular and morphological analyses of the oceanic copepod Pleuromamma abdominalis using a comprehensive collection of material from 944 individuals collected at 46 sites across the global ocean. Phylogenetic analyses of mitochondrial cytochrome oxidase subunit I (mtCOI) sequences detected eighteen divergent evolutionary lineages within P. abdominalis, with an additional four singleton specimens that were also genetically divergent. Two phylogenetically distinct groups, PLAB1 and PLAB2, were supported by concordant sequence variation in the nuclear large subunit ribosomal RNA gene (nLSU). Within PLAB1, two mtCOI clades, 1a-1 and 1b-1 were observed, and each clade contained geographically distinct sub-clades 1a-2 and 1b-2. PLAB2 was composed of sixteen well-supported mtCOI clades (2a-2p) as well as four singletons. High genetic divergence among the mtCOI lineages within both PLAB1 and PLAB2, ranging between 9.2-11.2% and 4.3-18.9% K2P distances respectively, suggests the presence of additional species within these groups. Significant differences were observed in the presence and shape of antennule spines of adult females between sympatric clades with genetic distances greater than 5.7-7.0% (K2P). The biogeographic distributions of mtCOI clades indicated greater specialization to particular oceanographic provinces than observed in the nominal species P. abdominalis, with mtCOI clades ranging from antitropical in subtropical waters of all three ocean basins (Atlantic, Pacific and Indian; clade 1b-1 and 2a) to taxa that are endemic to a particular ocean region, for example restricted to equatorial waters of the Atlantic Ocean (clade 1b

  19. CellTracker Green labelling vs. Rose Bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes

    Directory of Open Access Journals (Sweden)

    M. Grego

    2013-02-01

    Full Text Available Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week in the Northern Adriatic Sea, Mediterranean, and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG – new labelling approach for meiofauna – with the traditional Rose Bengal (RB staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. Surprisingly, RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more fine-scaled (days, hours, tipping points studies, especially on hypoxia and anoxia where it is necessary to resolve the course of events, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

  20. Growth and ontogeny of the tapeworm Schistocephalus solidus in its copepod first host affects performance in its stickleback second intermediate host

    Directory of Open Access Journals (Sweden)

    Benesh Daniel P

    2012-05-01

    Full Text Available Abstract Background For parasites with complex life cycles, size at transmission can impact performance in the next host, thereby coupling parasite phenotypes in the two consecutive hosts. However, a handful of studies with parasites, and numerous studies with free-living, complex-life-cycle animals, have found that larval size correlates poorly with fitness under particular conditions, implying that other traits, such as physiological or ontogenetic variation, may predict fitness more reliably. Using the tapeworm Schistocephalus solidus, we evaluated how parasite size, age, and ontogeny in the copepod first host interact to determine performance in the stickleback second host. Methods We raised infected copepods under two feeding treatments (to manipulate parasite growth, and then exposed fish to worms of two different ages (to manipulate parasite ontogeny. We assessed how growth and ontogeny in copepods affected three measures of fitness in fish: infection probability, growth rate, and energy storage. Results Our main, novel finding is that the increase in fitness (infection probability and growth in fish with larval size and age observed in previous studies on S. solidus seems to be largely mediated by ontogenetic variation. Worms that developed rapidly (had a cercomer after 9 days in copepods were able to infect fish at an earlier age, and they grew to larger sizes with larger energy reserves in fish. Infection probability in fish increased with larval size chiefly in young worms, when size and ontogeny are positively correlated, but not in older worms that had essentially completed their larval development in copepods. Conclusions Transmission to sticklebacks as a small, not-yet-fully developed larva has clear costs for S. solidus, but it remains unclear what prevents the evolution of faster growth and development in this species.

  1. CellTracker Green labelling vs. rose bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes

    Directory of Open Access Journals (Sweden)

    M. Grego

    2013-07-01

    Full Text Available Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week in the northern Adriatic Sea (Mediterranean and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG – new labelling approach for meiofauna – with the traditional rose bengal (RB staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as it does live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more precise quantification of community degradation, especially after an oxygen depletion event, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

  2. Linkage relationships among five enzyme-coding gene loci in the copepod Tigriopus californicus: a genetic confirmation of achiasmiatic meiosis.

    Science.gov (United States)

    Burton, R S; Feldman, M W; Swisher, S G

    1981-12-01

    Linkage relationships among five polymorphic enzyme-coding gene loci in the marine copepod Tigriopus californicus have been determined using electrophoretic analysis of progeny from laboratory matings. Phosphoglucose isomerase (PGI; EC 5.3.1.9) was found to be tightly linked to glutamate-pyruvate transaminase (GPT; EC 2.6..1.2), with only one recombinant observed in 364 progeny; glutamate-oxaloacetate transaminase (GOT; EC 2.6.1.1) is linked to the PGI-GPT pair, with a recombination fraction of approximately 0.20 in male double heterozygotes. Phosphoglucomutase (PGM; EC 2.7.5.1) and an esterase (EST; EC 3.1.1.1) are not linked to the PGI, GPT, GOT grouping, which has been designated linkage group I. Reciprocal crosses have revealed that no recombination occurs in female T. californicus; this observation confirms a previous report that meiosis in female Tigriopus is achiasmatic.

  3. Variation in tolerance to common marine pollutants among different populations in two species of the marine copepod Tigriopus.

    Science.gov (United States)

    Sun, Patrick Y; Foley, Helen B; Bao, Vivien W W; Leung, Kenneth M Y; Edmands, Suzanne

    2015-10-01

    Geographical variation in chemical tolerance within a species can significantly influence results of whole animal bioassays, yet a literature survey showed that the majority of articles using bioassays did not provide detail on the original field collection site of their test specimens confounding the ability for accurate replication and comparison of results. Biological variation as a result of population-specific tolerance, if not addressed, can be misinterpreted as experimental error. Our studies of two marine copepod species, Tigriopus japonicus and Tigriopus californicus, found significant intra- and inter-specific variation in tolerance to copper and tributyltin. Because both species tolerate copper concentrations orders of magnitude higher than those found in coastal waters, difference in copper tolerance may be a by-product of adaptation to other stressors such as high temperature. Controlling for inter-population tolerance variation will greatly strengthen the application of bioassays in chemical toxicity tests.

  4. Qualitative use of Dynamic Energy Budget theory in ecotoxicology. Case study on oil contamination and Arctic copepods

    Science.gov (United States)

    Klok, Chris; Hjorth, Morten; Dahllöf, Ingela

    2012-10-01

    The Dynamic Energy Budget (DEB) theory provides a logic and consistent framework to evaluate ecotoxicological test results. Currently this framework is not regularly applied in ecotoxicology given perceived complexity and data needs. However, even in the case of low data availability the DEB theory is already useful. In this paper we apply the DEB theory to evaluate the results in three previously published papers on the effects of PAHs on Arctic copepods. Since these results do not allow for a quantitative application we used DEB qualitatively. The ecotoxicological results were thereby set in a wider ecological context and we found a logical explanation for an unexpected decline in hatching success described in one of these papers. Moreover, the DEB evaluation helped to derive relevant ecological questions that can guide future experimental work on this subject.

  5. Prevalence of copepod parasite (Lernaeenicus polynemi infestation on Eleutheronema tetradactylum from Pazhayar coastal waters, southeast coast of India

    Directory of Open Access Journals (Sweden)

    Pazhanivel Bharadhirajan

    2013-11-01

    Full Text Available Objective: To study the prevalence and mean intensity of copepod parasite Lernaeenicus polynemi infestation on Eleutheronema tetradactylum from Pazayar, Tamil Nadu, southeast coast of India. Methods: The fish was collected from Pazhayar landing centre from January to December 2012 and their biometric measurements were examined. Toal number of infected fish and total number of parasites were recorded. Results: Higher prevalence and mean intensity of infestation of 35.23% and 3.1 were respectively reported during monsoon season of 2012. The parasitic infestations were scattered over the entire body of the host and targeted the different internal organs such as liver and the dorsal aorta. The highest intensity was reported to be 66 parasites in a single host. Conclusions: Due to the heavy parasitic attack the fish will suffer and its economical value or the marketability may reduce.

  6. Heterospecific mating and partial prezygotic reproductive isolation in the planktonic marine copepods Centropages typicus and Centropages hamatus

    DEFF Research Database (Denmark)

    Goetze, Erica

    2008-01-01

    Using three-dimensional (3D) video observations in laboratory experiments, I describe interspecific and intergeneric mating behaviors and motility patterns of the common planktonic marine copepods Centropages typicus, Centropages hamatus, and Temora longicornis. These observations are then used...... a spermatophore on the urosome of heterospecific females. T. longicornis males also detected the diffusible pheromone trail and pursued C. typicus females to the point of mate contact. Male mate-search tracking behavior was equally effective on diffusible pheromone trails of heterospecific and conspecific females...... incompatibility between species. Heterospecific mate encounter rates in the North Sea were maximal in late summer (August), up to,2,000 encounters m(-3) d(-1), and were comparable in magnitude to conspecific encounter rates during the same period. C. typicus females experience the highest incidence...

  7. Prevalence of copepod parasite (Lernaeenicus polynemi) infestation on Eleutheronema tetradactylum from Pazhayar coastal waters, southeast coast of India

    Institute of Scientific and Technical Information of China (English)

    Pazhanivel Bharadhirajan; Ayyaru Gopalakrishnan; Kuzhanthaivel Raja; Sambantham Murugan; Ramalingam Vijayakumar; Mohammad M Rahman

    2013-01-01

    Objective: To study the prevalence and mean intensity of copepod parasite Lernaeenicus polynemi infestation on Eleutheronema tetradactylum from Pazayar, Tamil Nadu, of India. southeast coast Methods: The fish was collected from Pazhayar landing centre from January to December 2012 aonf dp atrhaesiirt ebsi owmeeretr rice cmoredaesdu.rements were examined. Toal number of infected fish and total number Results: Higher prevalence and mean intensity of infestation of 35.23% and 3.1 were respectively rbeopdoyr toefd t hdeu rhinosgt manodn stoaorgne steedas tohne odfi f2f0e1r2e.n Tt hinet epranraals iotircg ainnsfe ssutacthio anss lwiveerre asncda tttheree ddo orvsaelr athoret ae.n Ttihree highest intensity was reported to be 66 parasites in a single host. Conclusions: Due to the heavy parasitic attack the fish will suffer and its economical value or the marketability may reduce.

  8. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. II. Protozooplankton and copepods

    DEFF Research Database (Denmark)

    Andersen, Nikolaj G.; Nielsen, Torkel Gissel; Jakobsen, Hans Henrik

    2011-01-01

    larvae and ostracods. Most of the recorded metazoan groups responded numerically to the frontal features (i.e. the surfacing of the isotherms) with high abundance in the STCZ compared with areas north and south of this. Juvenile copepod growth and egg production peaked in the STCZ, with a weight......The oligotrophic Sargasso Sea in the western part of the North Atlantic Ocean is influenced by a complex set of oceanographic features that might introduce nutrients and enhance productivity in certain areas. To increase our understanding of the variability in plankton communities and to determine...... the potential reasons why Atlantic eels Anguilla spp. use this area for spawning, we investigated the distribution and productivity of the zooplankton community across the Subtropical Convergence Zone (STCZ) in the Sargasso Sea in March and April 2007. The vertical and horizontal distributions of protozoans...

  9. Host response to the chondracanthid copepod Chondracanthus goldsmidi, a gill parasite of the striped trumpeter, Latris lineata (Forster), in Tasmania.

    Science.gov (United States)

    Andrews, M; Battaglene, S; Cobcroft, J; Adams, M; Noga, E; Nowak, B

    2010-03-01

    The chondracanthid copepod, Chondracanthus goldsmidi is an ectoparasite of gills, inner opercula and nasal cavities of cultured striped trumpeter, Latris lineata (Forster). Whilst often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite's attachment site, with papilloma-like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills; in contrast numerous mast cells were identified in the papilloma-like growths. Immunostaining identified piscidin-positive mast cells in the papilloma-like growths, presenting the first evidence of piscidin in the family Latridae.

  10. Notes on the Egg Bearing Cyclopoid Copepod, Oithona similis Claus, 1866 of the Arabian Sea

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    Jean J. JOSE

    2014-03-01

    Full Text Available Morphology of the marine egg bearing cyclopoid copepod Oithona similis occurring along the southwest coast of India [Vizhinjam (8º21'56"N; 76º59'39"E, Neendakara (8º57'29"N; 76º31'13"E, Cochin (9º56'16"N; 76º13'55"E and Calicut (11º13'33"N; 75º46'30"E] from January to December 2010 at different seasons (pre monsoon, monsoon and post monsoon were studied. Detailed comparison of the structure of different appendages of O. similis with those already available for the species from Norway, Japan, China, Spain and Russia revealed minute differences in the armature of appendages, number and arrangement of spines, setae of swimming legs and anal laminae. The total length of the specimen collected from all the four stations in the study ranged from 615 to 650μ. The smallest specimens were obtained from Calicut.

  11. Quantifying the elevation of mitochondrial DNA evolutionary substitution rates over nuclear rates in the intertidal copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S

    2012-06-01

    Mitochondrial DNA (mtDNA) genomes generally evolve rapidly in animals, but considerable variation in the rates of evolution of mtDNA occurs among taxa. Higher levels of mutation will tend to increase the amount of polymorphism, which should also scale with population size, but there are mixed signals from previous studies on the evolutionary outcomes of the interactions of these processes. The copepod Tigriopus californicus provides an interesting model in which to study the evolution of mtDNA because it has high levels of divergence among populations and there is the suggestion that this divergence could be involved in reproductive isolation. This species also appears to have an elevated mtDNA substitution rate, but previous studies did not provide an accurate measurement. This article examines the rate of mtDNA substitution versus nuclear substitution in T. californicus and finds that the mtDNA rate for synonymous sites averages 55-fold higher, a level that exceeds the rates found in most other invertebrates. Levels of polymorphism are also examined in both mtDNA and nuclear genes, and it is shown that the effective population size of mtDNA genes is much lower than that of nuclear genes. In addition, no correlation between polymorphism in mtDNA and nuclear genes is found across populations, which suggest factors other than demography may shape polymorphism in this species. The results from this study suggest that mtDNA is evolving at a very rapid rate in this copepod species, and this could increase the likelihood that mtDNA evolution is involved in the generation of reproductive isolation.

  12. Effects of UV radiation on hatching, lipid peroxidation, and fatty acid composition in the copepod Paracyclopina nana.

    Science.gov (United States)

    Won, Eun-Ji; Lee, Yeonjung; Han, Jeonghoon; Hwang, Un-Ki; Shin, Kyung-Hoon; Park, Heum Gi; Lee, Jae-Seong

    2014-09-01

    To evaluate the effects of UV radiation on the reproductive physiology and macromolecules in marine zooplankton, several doses of UV radiation were used to treat the copepod Paracyclopina nana, and we analyzed in vivo endpoints of their life cycle such as mortality and reproductive parameters with in vitro biochemical biomarkers such as reactive oxygen species (ROS), the modulated enzyme activity of glutathione S-transferase (GST) and superoxide dismutase (SOD), and the production of a byproduct of peroxidation (e.g. malonedialdehyde, MDA). After UV radiation, the survival rate of P. nana was significantly reduced. Also, egg sac damage and a reduction in the hatching rate of offspring were observed in UV-irradiated ovigerous females. According to the assessed biochemical parameters, we found dose-dependent increases in ROS levels and high levels of the lipid peroxidation decomposition product by 2 kJ m(-2), implying that P. nana was under off-balanced status by oxidative stress-mediated cellular damage. Antioxidant enzyme activities of GST and SOD increased over different doses of UV radiation. To measure UV-induced lipid peroxidation, we found a slight reduction in the composition of essential fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These findings indicate that UV radiation can induce oxidative stress-triggered lipid peroxidation with modulation of antioxidant enzyme activity, leading to a significant effect on mortality and reproductive physiology (e.g. fecundity). These results demonstrate the involvement of UV radiation on essential fatty acids and its susceptibility to UV radiation in the copepod P. nana compared to other species.

  13. BDE-47 induces oxidative stress, activates MAPK signaling pathway, and elevates de novo lipogenesis in the copepod Paracyclopina nana.

    Science.gov (United States)

    Lee, Min-Chul; Puthumana, Jayesh; Lee, Seung-Hwi; Kang, Hye-Min; Park, Jun Chul; Jeong, Chang-Bum; Han, Jeonghoon; Hwang, Dae-Sik; Seo, Jung Soo; Park, Heum Gi; Om, Ae-Son; Lee, Jae-Seong

    2016-12-01

    Brominated flame retardant, 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47), has received grave concerns as a persistent organic pollutant, which is toxic to marine organisms, and a suspected link to endocrine abnormalities. Despite the wide distribution in the marine ecosystem, very little is known about the toxic impairments on marine organisms, particularly on invertebrates. Thus, we examined the adverse effects of BDE-47 on life history trait (development), oxidative markers, fatty acid composition, and lipid accumulation in response to BDE-47-induced stress in the marine copepod Paracyclopina nana. Also, activation level of mitogen-activated protein kinase (MAPK) signaling pathways along with the gene expression profile of de novo lipogenesis (DNL) pathways were addressed. As a result, BDE-47 induced oxidative stress (e.g. reactive oxygen species, ROS) mediated activation of extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK) signaling cascades in MAPK pathways. Activated MAPK pathways, in turn, induced signal molecules that bind to the transcription factors (TFs) responsible for lipogenesis to EcR, SREBP, ChREBP promoters. Also, the stress stimulated the conversion of saturated fatty acids (SFAs) to polyunsaturated fatty acids (PUFAs), a preparedness of the organism to adapt the observed stress, which could be correlated with the elongase and desaturase gene (e.g. ELO3, Δ5-DES, Δ9-DES) expressions, and then extended to the delayed early post-embryonic development and increased accumulation of lipid droplets in P. nana. This study will provide a better understanding of how BDE-47 effects on marine invertebrates particularly on the copepods, an important link in the marine food chain.

  14. Abundance, distribution and population structure of the copepod Calanus finmarchicus in a springtime right whale feeding area in the southwestern Gulf of Maine

    Science.gov (United States)

    Wishner, Karen F.; Schoenherr, Jill R.; Beardsley, Robert; Chen, Changsheng

    Springtime aggregations of the planktivorous right whale ( Eubalaena glacialis) occur in the northern Great South Channel region of the southwestern Gulf of Maine, where they feed upon dense concentrations of the copepod Calanus finmarchicus. This association was studied during the multidisciplinary South Channel Ocean Productivity Experiment (SCOPEX) in 1988 and 1989. The spatial and temporal variability of the abundance, geographic distribution, and population structure of these copepods were analyzed using data from 99 vertically-stratified or horizontally-sequenced MOCNESS plankton tows. Higher water column abundances and higher relative proportion of older copepod lifestages occurred near feeding whales compared to sites without whales, but total water column copepod biomass and Calanus abundance did not always differ between these types of locations. This suggests that the whales seek out aggregations of older copepod lifestages rather than simply the most dense aggregations. Other factors (and perhaps an element of chance) may influence which specific patches, among all patches potentially suitable in terms of copepod abundance and age composition, the whales utilize at a particular time. The times and locations of the highest Calansus water column abundances varied between years, as did the presence of feeding whales, probably because of year-to-year differences in the springtime temperature cycle and current strength. A temporal progression of lifestages occurred within the region in both years during the roughly 3-week duration of each survey, indicative of a growing rather than a diapausing population, at least up to the copepodite 4 (C4) stage. Due in part to a delay in the springtime warming in 1989 compared to 1988, the copepod development cycle, which is largely driven by in situ temperature, was delayed about 1-2 weeks in 1989. Peak abundances of younger Calanus were found in the northwestern part of the region each year, whereas peak abundances of

  15. Closely linked H2B genes in the marine copepod, Tigriopus californicus indicate a recent gene duplication or gene conversion event.

    Science.gov (United States)

    Brown, D; Cook, A; Wagner, M; Wells, D

    1992-01-01

    Two nonallelic histone gene clusters were characterized in the marine copepod, Tigriopus californicus. The DNA sequence of one of the clusters reveals six genes in the contiguous arrangement of H2B, H1, H3, H4, H2B and H2A. The order of genes within the second cluster is H3, H4, H2B and H2A. There is no evidence for the presence of an H1 gene in this cluster. Comparison of the three copepod H2B genes reveals a high degree of similarity between the 5' upstream regions and between the amino terminal halves of the two H2B genes found within the same cluster. From these data we infer that gene duplication and/or gene conversion events occurred within this cluster in the recent past.

  16. The efficiency of a new hydrodynamic cavitation pilot system on Artemia salina cysts and natural population of copepods and bacteria under controlled mesocosm conditions.

    Science.gov (United States)

    Cvetković, Martina; Grego, Mateja; Turk, Valentina

    2016-04-15

    A study of the efficiency of hydrodynamic cavitation and separation was carried out to evaluate an innovative, environmentally safe and acceptable system for ballast water treatment for reducing the risk of introducing non-native species worldwide. Mesocosm experiments were performed to assess the morphological changes and viability of zooplankton (copepods), Artemia salina cysts, and the growth potential of marine bacteria after the hydrodynamic cavitation treatment with a different number of cycles. Our preliminary results confirmed the significant efficiency of the treatment since more than 98% of the copepods and A. salina cysts were damaged, in comparison with the initial population. The efficiency increased with the number of the hydrodynamic cavitation cycles, or in combination with a separation technique for cysts. There was also a significant decrease in bacterial abundance and growth rate, compared to the initial number and growth potential.

  17. [Species composition and distribution characteristics of pelagic copepods in the Northern Sea of Fujian during withdraw of Zhe-Min coastal current].

    Science.gov (United States)

    Wang, Yan-Guo; Lin, Jing-Hong; Wang, Chun-Guang; Lin, Mao

    2012-06-01

    Based on oceanographic survey data in April 2009 in the north central Taiwan Strait, ecological characteristics such as species composition, individual density, dominant species and distribution were analyzed. The results were compared with the same area survey in spring 2007 for discuss the annual variety. The result shows that 48 pelagic copepods species have been recognized, and most of them belongs to Calanodia. The higher species number occurs in southern and eastern area. The average density of pelagic copepoda was 231.96 ind x m(-3). As to the horizontal distribution, the coast and northern areas are higher than those of eastern and southern areas of the density of pelagic copepods which are dependent on the dominant species Calanus sinicus and Euchaeta plana. The community structure of pelagic copepoda was same to the other survey result, which shows low biodiversity index with remarkable dominant species. Owing to the Zhe-Min coastal current effect, the higher density distribution is different in 2007 and 2009. As to the ecological character, all the copepoda in this paper belong to warm-water, warm-temperature and tropic oceanic groups. Warm-water and tropic oceanic groups are the dominant groups of the pelagic copepods composition. When it comes to density, warm-temperature group is the dominant. The relationship of species number, diversity index and abundance with the environment were also discussed in this paper. The result showed that the pelagic copepoda species number and diversity would increase with the temperature and salty increase.

  18. Detailed surface morphology of the 'lobster louse' copepod, Nicothoë astaci, a haematophagous gill parasite of the European lobster, Homarus gammarus.

    Science.gov (United States)

    Davies, Charlotte E; Thomas, Gethin R; Maffeis, Thierry G G; Wootton, Emma C; Penny, Mark W; Rowley, Andrew F

    2014-10-01

    The ectoparasitic copepod, Nicothoë astaci (the 'lobster louse'), infests the gills of the European lobster, Homarus gammarus. There have been limited studies on this haematophagous species; therefore knowledge of this parasite is rudimentary. The current study examines the surface morphology of this parasitic copepod, detached from the host, concentrating on adaptations of the suctorial mouthpart, the oral disc. Cryo-scanning electron microscopy revealed structural adaptations that facilitate attachment of these parasites to the gill filaments of their lobster host. The aperture of the feeding channel, through which host haemolymph is drawn, is only ca. 5μm in diameter. The edge of the oral disc is lined with numerous setae, whilst the surface of the disc is covered with large numbers of small (<1μm in diameter) teeth-like structures, which presumably pierce through, and grip, the cuticle lining of the host's gill. Overall, these structures are thought to provide a 'vacuum seal' to assist in pumping of blood, via peristalsis, into the alimentary canal of the copepod host.

  19. Impacts of restoration of an uncontrolled phosphogypsum dumpsite on the seasonal distribution of abiotic variables, phytoplankton, copepods, and ciliates in a man-made solar saltern.

    Science.gov (United States)

    Kobbi-Rebai, Rayda; Annabi-Trabelsi, Neila; Khemakhem, Hajer; Ayadi, Habib; Aleya, Lotfi

    2013-03-01

    The restoration of an uncontrolled phosphogypsum landfill was investigated for its effects on the seasonal distribution of phytoplankton, ciliates, and copepods. Sampling was carried out monthly from September 2007 to August 2008 at four ponds of increasing salinity (A1, 41 psu; A5, 46 psu; A16, 67 psu; and C31, 77 psu) in the Sfax solar saltern (southeastern Tunisia). Physicochemical and biological analyses were carried out using standard methods. Results showed drastic reduction of phosphate input and greater diversity of phytoplankton, ciliates, and copepods than before restoration. Pennate diatoms and new ciliates, considered bio-indicators of less-stressed marine ecosystems, proliferated in the A1 pond for the first time after restoration. Copepods appeared to feed on a wide range of prey. Economically, removal of the 1.7 million m(3) of phosphate improved the quality of the site's salt production, enabling the salt company to receive the quality ISO 9001 accreditation.

  20. Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Hwang, Un-Ki [Marine Ecological Risk Assessment Center, West Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Incheon 400-420 (Korea, Republic of); Kim, Il-Chan; Yim, Joung Han [Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840 (Korea, Republic of); Leung, Kenneth Mei Yee [School of Biological Sciences and the Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Lee, Yong Sung [Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-07-01

    Highlights: • Mortality rate was significantly increased in response to gamma radiation. • A dose-dependent reduction in fecundity of ovigerous females. • Growth retardation, particularly at the nauplius stage. • Upon gamma radiation, T. japonicus showed an increased ROS levels. • Antioxidant genes and Hsps genes were upregulated at sublethal doses. - Abstract: Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96 h, even in response to exposure to a high dose (800 Gy) of radiation, but mortality rate was significantly increased 120 h (5 days) after exposure to 600 or 800 Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50 Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200 Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma

  1. Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.

    Science.gov (United States)

    Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Leung, Kenneth Mei Yee; Lee, Yong Sung; Lee, Jae-Seong

    2014-07-01

    Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular chaperone genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase

  2. Multi-decadal range changes vs. thermal adaptation for north east Atlantic oceanic copepods in the face of climate change.

    Science.gov (United States)

    Hinder, Stephanie L; Gravenor, Mike B; Edwards, Martin; Ostle, Clare; Bodger, Owen G; Lee, Patricia L M; Walne, Antony W; Hays, Graeme C

    2014-01-01

    Populations may potentially respond to climate change in various ways including moving to new areas or alternatively staying where they are and adapting as conditions shift. Traditional laboratory and mesocosm experiments last days to weeks and thus only give a limited picture of thermal adaptation, whereas ocean warming occurring over decades allows the potential for selection of new strains better adapted to warmer conditions. Evidence for adaptation in natural systems is equivocal. We used a 50-year time series comprising of 117 056 samples in the NE Atlantic, to quantify the abundance and distribution of two particularly important and abundant members of the ocean plankton (copepods of the genus Calanus) that play a key trophic role for fisheries. Abundance of C. finmarchicus, a cold-water species, and C. helgolandicus, a warm-water species, were negatively and positively related to sea surface temperature (SST) respectively. However, the abundance vs. SST relationships for neither species changed over time in a manner consistent with thermal adaptation. Accompanying the lack of evidence for thermal adaptation there has been an unabated range contraction for C. finmarchicus and range expansion for C. helgolandicus. Our evidence suggests that thermal adaptation has not mitigated the impacts of ocean warming for dramatic range changes of these key species and points to continued dramatic climate induced changes in the biology of the oceans.

  3. Nuclear and mitochondrial gene genealogies and allozyme polymorphism across a major phylogeographic break in the copepod Tigriopus californicus.

    Science.gov (United States)

    Burton, R S; Lee, B N

    1994-05-24

    The genetic structure of natural populations is frequently inferred from geographic distributions of alleles at multiple gene loci. Surveys of allozyme polymorphisms in the tidepool copepod Tigriopus californicus have revealed sharp genetic differentiation of populations, indicating that gene flow among populations is highly restricted. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial gene genealogies. DNA sequences of the mtDNA-encoded cytochrome-c oxidase subunit I gene from 21 isofemale lines derived from seven populations reveal a phylogeographic break between populations north and south of Point Conception, California, with sequence divergence across the break exceeding 18%, the highest level of mtDNA divergence yet reported among conspecific populations. Divergence between populations based on 22 sequences of the nuclear histone H1 gene is geographically concordant with the mitochondrial sequences. In contrast with previously studied nuclear genes in other sexually reproducing metazoans, the H1 gene genealogy from T. californicus shows no evidence of recombination. The apparent absence of intragenic recombinants probably results from the persistent lack of gene flow among geographically separated populations, a conclusion strongly supported by allozyme data and the mitochondrial gene genealogy. Despite strong population differentiation at allozyme loci, the phylogeographic break identified by the DNA sequences was not evident in the allozyme data.

  4. Complex deleterious interactions associated with malic enzyme may contribute to reproductive isolation in the copepod Tigriopus californicus.

    Directory of Open Access Journals (Sweden)

    Christopher S Willett

    Full Text Available Dobzhansky-Muller incompatibilities can result from the interactions of more than a single pair of interacting genes and there are several different models of how such complex interactions can be structured. Previous empirical work has identified complex conspecific epistasis as a form of complex interaction that has contributed to postzygotic reproductive isolation between taxa, but other forms of complexity are also possible. Here, I probe the genetic basis of reproductive isolation in crosses of the intertidal copepod Tigriopus californicus by looking at the impact of markers in genes encoding metabolic enzymes in F(2 hybrids. The region of the genome associated with the locus ME2 is shown to have strong, repeatable impacts on the fitness of hybrids in crosses and epistatic interactions with another chromosomal region marked by the GOT2 locus in one set of crosses. In a cross between one of these populations and a third population, these two regions do not appear to interact despite the continuation of a large effect of the ME2 region itself in both crosses. The combined results suggest that the ME2 chromosomal region is involved in incompatibilities with several unique partners. If these deleterious interactions all stem from the same factor in this region, that would suggest a different form of complexity from complex conspecific epistasis, namely, multiple independent deleterious interactions stemming from the same factor. Confirmation of this idea will require more fine-scale mapping of the interactions of the ME2 region of the genome.

  5. An H3-H4 histone gene pair in the marine copepod Tigriopus californicus, contains an intergenic dyad symmetry element.

    Science.gov (United States)

    Porter, D; Brown, D; Wells, D

    1991-01-01

    Histone genes are one of the most widely studied multigene families in eucaryotes. Over 200 histone genes have been sequenced, primarily in vertebrates, echinoderms, fungi and plants. We present here the structure and genomic orientation of an H3-H4 histone gene pair from the marine copepod, Tigriopus californicus. These histone gene sequences are the first to be determined for the class Crustacea and among the first to be determined for protostomes. The H4 and H3 genes in Tigriopus are shown to be adjacent, to have opposite polarity, and to contain a 26 bp region of dyad symmetry centrally located within the spacer region between the two genes. A similarly located dyad element has been found in yeast which contributes to the coordinated cell cycle control of the adjacent histone genes. The Tigriopus H3-H4 histone gene pair is clustered with one H2A and two H2B histone genes on a 15 kb genomic Bam H1 fragment. The H4 gene sequence predicts an H4 protein with an unusual serine to threonine substitution at the amino terminal residue. The H3 gene sequence predicts an H3 protein which is identical to the vertebrate H3.2 histone.

  6. Complex deleterious interactions associated with malic enzyme may contribute to reproductive isolation in the copepod Tigriopus californicus.

    Science.gov (United States)

    Willett, Christopher S

    2011-01-01

    Dobzhansky-Muller incompatibilities can result from the interactions of more than a single pair of interacting genes and there are several different models of how such complex interactions can be structured. Previous empirical work has identified complex conspecific epistasis as a form of complex interaction that has contributed to postzygotic reproductive isolation between taxa, but other forms of complexity are also possible. Here, I probe the genetic basis of reproductive isolation in crosses of the intertidal copepod Tigriopus californicus by looking at the impact of markers in genes encoding metabolic enzymes in F(2) hybrids. The region of the genome associated with the locus ME2 is shown to have strong, repeatable impacts on the fitness of hybrids in crosses and epistatic interactions with another chromosomal region marked by the GOT2 locus in one set of crosses. In a cross between one of these populations and a third population, these two regions do not appear to interact despite the continuation of a large effect of the ME2 region itself in both crosses. The combined results suggest that the ME2 chromosomal region is involved in incompatibilities with several unique partners. If these deleterious interactions all stem from the same factor in this region, that would suggest a different form of complexity from complex conspecific epistasis, namely, multiple independent deleterious interactions stemming from the same factor. Confirmation of this idea will require more fine-scale mapping of the interactions of the ME2 region of the genome.

  7. Molecular evolution at the cytochrome oxidase subunit 2 gene among divergent populations of the intertidal copepod, Tigriopus californicus.

    Science.gov (United States)

    Rawson, Paul D; Burton, Ronald S

    2006-06-01

    The cytochrome c oxidase subunit 2 gene (COII) encodes a highly conserved protein that is directly responsible for the initial transfer of electrons from cytochrome c to cytochrome c oxidase (COX) crucial to the production of ATP during cellular respiration. Despite its integral role in electron transport, we have observed extensive intraspecific nucleotide and amino acid variation among 26 full-length COII sequences sampled from seven populations of the marine copepod, Tigriopus californicus. Although intrapopulation divergence was virtually nonexistent, interpopulation divergence at the COII locus was nearly 20% at the nucleotide level, including 38 nonsynonymous substitutions. Given the high degree of interaction between the cytochrome c oxidase subunit 2 protein (COX2) and the nuclear-encoded subunits of COX and cytochrome c (CYC), we hypothesized that some codons in the COII gene are likely to be under positive selection in order to compensate for amino acid substitutions in other subunits. Estimates of the ratio of nonsynonymous to synonymous substitution (omega), obtained using a series of maximum likelihood models of codon substitution, indicated that the majority of codons in T. californicus COII are under strong purifying selection (omega < 1), while approximately 4% of the sites in this gene appear to evolve under relaxed selective constraint (omega = 1). A branch-site maximum likelihood model identified three sites that may have experienced positive selection within the central California sequence clade in our COII phylogeny; these results are consistent with previous studies showing functional and fitness consequences among interpopulation hybrids between central and northern California populations.

  8. Sex without sex chromosomes: genetic architecture of multiple loci independently segregating to determine sex ratios in the copepod Tigriopus californicus.

    Science.gov (United States)

    Alexander, H J; Richardson, J M L; Edmands, S; Anholt, B R

    2015-12-01

    Sex-determining systems are remarkably diverse and may evolve rapidly. Polygenic sex-determination systems are predicted to be transient and evolutionarily unstable, yet examples have been reported across a range of taxa. Here, we provide the first direct evidence of polygenic sex determination in Tigriopus californicus, a harpacticoid copepod with no heteromorphic sex chromosomes. Using genetically distinct inbred lines selected for male- and female-biased clutches, we generated a genetic map with 39 SNPs across 12 chromosomes. Quantitative trait locus mapping of sex ratio phenotype (the proportion of male offspring produced by an F2 female) in four F2 families revealed six independently segregating quantitative trait loci on five separate chromosomes, explaining 19% of the variation in sex ratios. The sex ratio phenotype varied among loci across chromosomes in both direction and magnitude, with the strongest phenotypic effects on chromosome 10 moderated to some degree by loci on four other chromosomes. For a given locus, sex ratio phenotype varied in magnitude for individuals derived from different dam lines. These data, together with the environmental factors known to contribute to sex determination, characterize the underlying complexity and potential lability of sex determination, and confirm the polygenic architecture of sex determination in T. californicus.

  9. Cymbopogon citratus-synthesized gold nanoparticles boost the predation efficiency of copepod Mesocyclops aspericornis against malaria and dengue mosquitoes.

    Science.gov (United States)

    Murugan, Kadarkarai; Benelli, Giovanni; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Jeyalalitha, Tirupathi; Dinesh, Devakumar; Nicoletti, Marcello; Hwang, Jiang-Shiou; Suresh, Udaiyan; Madhiyazhagan, Pari

    2015-06-01

    Plant-borne compounds can be employed to synthesize mosquitocidal nanoparticles that are effective at low doses. However, how they affect the activity of mosquito predators in the aquatic environment is unknown. In this study, we synthesized gold nanoparticles (AuN) using the leaf extract of Cymbopogon citratus, which acted as a reducing and capping agent. AuN were characterized by a variety of biophysical methods and sorted for size in order to confirm structural integrity. C. citratus extract and biosynthesized AuN were tested against larvae and pupae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti. LC₅₀ of C. citratus extract ranged from 219.32 ppm to 471.36 ppm. LC₅₀ of AuN ranged from 18.80 ppm to 41.52 ppm. In laboratory, the predatory efficiency of the cyclopoid crustacean Mesocyclops aspericornis against A. stephensi larvae was 26.8% (larva I) and 17% (larva II), while against A. aegypti was 56% (I) and 35.1% (II). Predation against late-instar larvae was minimal. In AuN-contaminated environment,predation efficiency against A. stephensi was 45.6% (I) and 26.7% (II), while against A. aegypti was 77.3% (I) and 51.6% (II). Overall, low doses of AuN may help to boost the control of Anopheles and Aedes larval populations in copepod-based control programs.

  10. Gamma radiation induces growth retardation, impaired egg production, and oxidative stress in the marine copepod Paracyclopina nana

    Energy Technology Data Exchange (ETDEWEB)

    Won, Eun-Ji; Lee, Jae-Seong, E-mail: jslee2@skku.edu

    2014-05-01

    Highlights: • Mortality was increased with a dose dependent manner in ovigerous females of Paracyclopina nana. • Developmental impairments were observed in gamma irradiated nauplii. • Ovigerous females exposed to more than 50 Gy could not have normal two bilateral egg sacs. • Oxidative levels increased with antioxidant enzyme activities in the gamma irradiated P. nana. • The molecular indices (antioxidant enzymes and heat shock protein) were also increased. - Abstract: Accidental nuclear radioisotope release into the ocean from nuclear power plants is of concern due to ecological and health risks. In this study, we used the marine copepod Paracyclopina nana to examine the effects of radioisotopes on marine organisms upon gamma radiation, and to measure the effects on growth and fecundity, which affect population and community structure. Upon gamma radiation, mortality (LD50 – 96 h = 172 Gy) in P. nana was significantly increased in a dose-dependent manner in ovigerous P. nana females. For developmental impairment of gamma-irradiated nauplii, we observed growth retardation; in over 30 Gy-irradiated groups, offspring did not grow to adults. Particularly, over 50 Gy-irradiated ovigerous P. nana females did not have normal bilateral egg sacs, and their offspring did not develop normally to adulthood. Additionally, at over 30 Gy, we found dose-dependent increases in oxidative levels with elevated antioxidant enzyme activities and DNA repair activities. These findings indicate that gamma radiation can induce oxidative stress and DNA damage with growth retardation and impaired reproduction.

  11. Gamma radiation induces growth retardation, impaired egg production, and oxidative stress in the marine copepod Paracyclopina nana.

    Science.gov (United States)

    Won, Eun-Ji; Lee, Jae-Seong

    2014-05-01

    Accidental nuclear radioisotope release into the ocean from nuclear power plants is of concern due to ecological and health risks. In this study, we used the marine copepod Paracyclopina nana to examine the effects of radioisotopes on marine organisms upon gamma radiation, and to measure the effects on growth and fecundity, which affect population and community structure. Upon gamma radiation, mortality (LD50 - 96 h=172 Gy) in P. nana was significantly increased in a dose-dependent manner in ovigerous P. nana females. For developmental impairment of gamma-irradiated nauplii, we observed growth retardation; in over 30 Gy-irradiated groups, offspring did not grow to adults. Particularly, over 50 Gy-irradiated ovigerous P. nana females did not have normal bilateral egg sacs, and their offspring did not develop normally to adulthood. Additionally, at over 30 Gy, we found dose-dependent increases in oxidative levels with elevated antioxidant enzyme activities and DNA repair activities. These findings indicate that gamma radiation can induce oxidative stress and DNA damage with growth retardation and impaired reproduction.

  12. The reaction of European lobster larvae (Homarus gammarus) to different quality food: effects of ontogenetic shifts and pre-feeding history.

    Science.gov (United States)

    Schoo, Katherina L; Aberle, Nicole; Malzahn, Arne M; Schmalenbach, Isabel; Boersma, Maarten

    2014-02-01

    Young larval stages of many organisms represent bottlenecks in the life-history of many species. The high mortality commonly observed in, for example, decapod larvae has often been linked to poor nutrition, with most studies focussing on food quantity. Here, we focus instead on the effects of quality and have investigated its effects on the nutritional condition of lobster larvae. We established a tri-trophic food chain consisting of the cryptophyte Rhodomonas salina, the calanoid copepod Acartia tonsa and larvae of the European lobster Homarus gammarus. In a set of experiments, we manipulated the C:N:P stoichiometry of the primary producers, and accordingly those of the primary consumer. In a first experiment, R. salina was grown under N- and P-limitation and the nutrient content of the algae was manipulated by addition of the limiting nutrient to create a food quality gradient. In a second experiment, the effect on lobster larvae of long- and short-term exposure to food of varying quality during ontogenetic development was investigated. The condition of the lobster larvae was negatively affected even by subtle N- and P-nutrient limitations of the algae. Furthermore, younger lobster larvae were more vulnerable to nutrient limitation than older ones, suggesting an ontogenetic shift in the capacity of lobster larvae to cope with low quality food. The results presented here might have substantial consequences for the survival of lobster larvae in the field, as, in the light of future climate change and re-oligotrophication of the North Sea, lobster larvae might face marked changes in temperature and nutrient conditions, thus significantly altering their condition and growth.

  13. Impacts of an uncontrolled phosphogypsum dumpsite on summer distribution of phytoplankton, copepods and ciliates in relation to abiotic variables along the near-shore of the southwestern Mediterranean coast.

    Science.gov (United States)

    Rekik, Amira; Drira, Zaher; Guermazi, Wassim; Elloumi, Jannet; Maalej, Sami; Aleya, Lotfi; Ayadi, Habib

    2012-02-01

    In connection with the Taparura Project, studies of spatial distribution of the crustacean zooplankton community, nutrients, phytoplankton and ciliates were conducted in July 2007 at 45 stations spread over fifteen transects along the coast north of Sfax. The results showed that the N/P ratio was lower than the Redfield ratio, suggesting potential N limitation. Phytoplankton was characterised by the proliferation of several diatoms, while ciliates were largely dominated by spirotrichs. Copepods were the most abundant zooplankton present during the entire study period, comprising 61% of the total zooplankton community. Twelve copepod families were identified at every station, with a high percentage of Oithonidae (77% of copepods) dominated by Oithona nana. The abundance of this species was correlated with that of diatoms, Cocoolithophorideae and ciliated Colpodea, suggesting that O. nana may feed on a wide range of prey. Despite human pressure and industrial activities, the coastal waters north of Sfax showed a wide diversity of phytoplankton, ciliates and zooplankton.

  14. Extensive cross-disciplinary analysis of biological and chemical control of Calanus finmarchicus reproduction during an aldehyde forming diatom bloom in mesocosms

    DEFF Research Database (Denmark)

    Jonasdottir, Sigrun; Dutz, Jörg; Koski, Marja;

    2011-01-01

    Egg and faecal pellet production and egg hatching success of the calanoid copepod Calanus finmarchicus were monitored over a period of 14 days (14-28 April, 2008) while fed water from 4 differently treated mesocosms and ambient water. Two of the mesocosms used were inoculated with the polyunsatur......Egg and faecal pellet production and egg hatching success of the calanoid copepod Calanus finmarchicus were monitored over a period of 14 days (14-28 April, 2008) while fed water from 4 differently treated mesocosms and ambient water. Two of the mesocosms used were inoculated...

  15. Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeonghoon; Won, Eun-Ji; Lee, Min-Chul [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Seo, Jung Soo [Pathology Team, National Fisheries Research & Development Institute, Busan 619-902 (Korea, Republic of); Lee, Su-Jae [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-08-15

    Highlights: • The repercussions of BDE-47 and PFOS were occurred on development and fecundity. • BDE-47 and PFOS can induce oxidative stress through the generation of ROS. • The expression of defensome was changed in response to BDE-47 and PFOS. • ROS-induced DNA damage in BDE-47 and PFOS exposure lead to apoptosis and DNA repair. - Abstract: 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and perfluorooctane sulfonate (PFOS) are widely dispersed persistent organic pollutants (POPs) in the marine ecosystem. However, their toxic effects on marine organisms are still poorly understood. In this study, we investigated the effects of BDE-47 and PFOS on development and reproduction at the organismal level and reactive oxygen species (ROS) production and gene expression patterns of the defensome at the cellular level in the intertidal copepod Tigriopus japonicus. In copepods exposed to BDE-47 and PFOS, we observed developmental retardation and reduced fecundity, suggesting repercussions on in vivo endpoints through alterations to the normal molting and reproduction system of T. japonicus. BDE-47 and PFOS increased levels of ROS in T. japonicus in a concentration-dependent manner, indicating that POPs can induce oxidative stress through the generation of ROS. Additionally, transcript profiles of genes related to detoxification (e.g., CYPs), antioxidant functions (e.g., GST- sigma, catalase, MnSOD), apoptosis (e.g., p53, Rb), and cellular proliferation (e.g., PCNA) were modulated over 72 h in response to BDE-47 (120 μg/L) and PFOS (1000 μg/L). These findings indicate that BDE-47 and PFOS can induce oxidative stress-mediated DNA damage repair systems with transcriptional regulation of detoxification, antioxidant, and apoptosis-related genes, resulting in developmental retardation and reduced fecundity in the copepod T. japonicus.

  16. Diversity and community structure of harpacticoid copepods associated with cold-water coral substrates in the Porcupine Seabight (North-East Atlantic)

    Science.gov (United States)

    Gheerardyn, Hendrik; de Troch, Marleen; Vincx, Magda; Vanreusel, Ann

    2010-03-01

    The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types were distinguished: dead fragments of the cold-water coral Lophelia pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it appears that coral fragments and underlying sediment do not harbour distinctly different assemblages, with Ectinosomatidae, Ameiridae, Pseudotachidiidae, Argestidae and Miraciidae as most abundant. Conclusions on assemblage structure and diversity of the sponge skeletons are limited as only two samples were available. Similarity analysis at species level showed a strong variation in the sediment samples, which did not harbour a distinctly different assemblage in opposition to the coral and sponge samples. Several factors (sediment infill on the hard substrates, mobility of the copepods, limited sample sizes) are proposed to explain this apparent lack of a distinct difference between the microhabitats. Coral fragments and sediment were both characterised by high species diversity and low species dominance, which might indicate that copepod diversity is not substantially influenced by hydrodynamical stress. The additive partitioning of species diversity showed that by adding locations species richness was greatly enhanced. The harpacticoid community in the cold-water coral degradation zone is highly diverse and includes 157 species, 62 genera and 19 families. Information from neighbouring soft-bottom regions is necessary to assess whether total species diversity is increased by the presence of these complex habitat-providing substrates.

  17. Sensitivity of the marine benthic copepod Tisbe biminiensis (copepoda, harpacticoida to potassium dichromate and sediment particle size

    Directory of Open Access Journals (Sweden)

    Cristiane M. V. Araújo-Castro

    2009-03-01

    Full Text Available For the future use of the marine benthic copepod Tisbe biminiensis in solid-phase sediment toxicological bioassays, the present study investigated the effect of muddy sediment from the Maracaípe estuary (northeastern Brazil, sediment particle size and the reference toxicant potassium dichromate on the species. Muddy sediment from Maracaípe can be used as control sediment, since it does not interfere in the copepod life-cycle and has metal contamination levels that are unlikely to produce any detrimental biological effects on benthic invertebrates. Neither survival nor fecundity was affected by grain size, suggesting that this species can be used with any kind of sediment from muddy to sandy. The sensitivity of T. biminiensis to K2Cr2O7 in acute tests was similar to that of other organisms. The LC50 (lethal concentration to 50% of the test organisms medium values for T. biminiensis were 7.51, 4.68 and 3.19 mg L-1 for Cr in 48, 72 and 96 h, respectively. These results suggest that T. biminiensis is a promising organism for use in solid-phase sediment toxicity assessments.Visando o uso futuro do copépodo marinho bentônico Tisbe biminiensis em bioensaios toxicológicos de sedimentos na fase sólida, o presente estudo investigou o efeito do sedimento lamoso do estuário de Maracaípe (Nordeste do Brasil. Foram considerados a granolometria e o tóxico de referência dicromato de potássio sobre a espécie. O sedimento lamoso de Maracaípe pode ser usado como controle, uma vez que não interfere no ciclo de vida do copépodo e possui níveis de contaminação de metais que não causariam efeitos biológicos em invertebrados bentônicos. Nem a sobrevivência ou fecundidade foi afetada pelo tamanho do grão, sugerindo que esta espécie pode ser usada com qualquer tipo de sedimento, de lama a areia. A sensibilidade de T. biminiensis ao K2Cr2O7 em testes agudos foi similar a de outros organismos. Os valores de CL50 (concentração letal a 50% dos

  18. Producing a problem? Effects of produced water contaminants (PAHs, radium-226, barium and scale inhibitor) on the copepod Calanus finmarchicus

    Energy Technology Data Exchange (ETDEWEB)

    Kiel Jensen, Louise [Norwegian Radiation Protection Authority, Fram Centre, 9296 Tromsoe (Norway); Halvorsen, Elisabeth; Gammelsaeter Hallanger, Ingeborg [UiT The Arctic University of Norway, Department of Arctic and Marine Biology, P.O. box 6050 Langnes, 9037 Tromsoe (Norway); Tollefsen, Knut Erik; Brooks, Steven [Norwegian Institute for Water Research, Gaustadalleen 21, 0349 Oslo (Norway); Hansen, Bjoern Henrik [SINTEF Materials and Chemistry, Marine Environmental Technology, Brattoerkaia 17B, 7010 Trondheim (Norway)

    2014-07-01

    In the Barents Sea region new petroleum fields are discovered yearly and the extraction of petroleum products are expected to increase in the upcoming years. Despite enhanced technology and stricter governmental legislation, establishing the petroleum industry in the Barents Sea will introduce a new source of Naturally Occurring Radioactive Material (NORM) to the area as some discharges of produced water will be allowed. Whether the presence of produced water poses a risk to the Arctic marine life remains to be examined. We examined effects on the copepod species Calanus finmarchicus after exposure to several compounds found in produced water. A mixture of polycyclic aromatic hydrocarbons and alkyl phenols commonly found in produced water was used as a proxy of the organic fraction of the produced water (hereafter termed APW (Artificial Produced Water)). In addition, exposures were done using radium-226 (proxy for NORM), barium (proxy for metals) and a scale inhibitor (SI -4470, M-I SWACO, Schlumberger Norge AS). Short-term screening tests on a range of concentrations of all compounds were run to assess the hatchability of the eggs and early survival of the nauplii. Long-term experiments were carried out with exposure concentrations at realistic levels found in the vicinity of known discharge points. The copepod C. finmarchicus is considered a keystone species in the Barents Sea ecosystem as it represents the major pathway of energy transfer from lower to higher trophic levels. We have examined sub-lethal effects on early life stages and on adult females. The hatchability of the eggs was not affected by concentrations well above realistic environmental levels. However, the instant mortality of the hatched larvae increased with higher concentrations of barium, scale inhibitor and APW, though not with higher radium-226 concentration. When examining the long-term growth of the nauplii, we found that the survival was poor in the APW treatment, and in the barium

  19. Genomic characterization and phylogenetic position of two new species in Rhabdoviridae infecting the parasitic copepod, salmon louse (Lepeophtheirus salmonis.

    Directory of Open Access Journals (Sweden)

    Arnfinn Lodden Økland

    Full Text Available Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11,600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses.

  20. The effect of a biologically produced structure on the benthic copepods of a deep-sea site

    Science.gov (United States)

    Thistle, David; Eckman, James E.

    1990-04-01

    In deep-sea soft bottoms, a variety of organisms produce structures that persist for long periods, even after the structures are vacated. It has been hypothesized that these structures are a major source of patchiness in these communities and are important in maintaining the high diversities that characterize the deep sea. Although several studies have shown species' abundances to be correlated with structures, the mechanisms underlying the associations are not known. We attempted to discover these mechanisms, focusing on the responses of benthic copepods to mudballs made by the polychaete Tharyx luticastellus at a site at 1050 m depth in San Diego Trough (32° 52.4'N, 117°45.5'W). It was found that seven out of 40 species responded. Four were more abundant around the structure only when the worm was in residence. These species apparently benefit from some consequences of the worm's presence. Given that bacterial abundance is higher about occupied Tharyx mudballs than nearby controls, it may be that the attractiveness occupied Tharyx mudballs arises from the provision of food. Three species responded to unoccupied mudballs. We measured responses to various types of mudball mimics to determine whether responses were to a habitat provided by the mudball, to a refuge from predation in its vicinity, or to hydrodynamically mediated increases in local food availability. Two of the species appeared to use the mudball as a habitat, the third as a refuge from infaunal predators. The results indicate that biologically produced structures can persist long enough to be viewed as habitat heterogeneity by other species in the community and that this source of patchiness is important to deep-sea species.

  1. Meiobenthic diversity in space and time: The case of harpacticoid copepods in two Mediterranean microtidal sandy beaches

    Science.gov (United States)

    Sevastou, Katerina; Lampadariou, Nikolaos; Eleftheriou, Anastasios

    2011-10-01

    Meiobenthic data from two microtidal sandy beaches of the eastern Mediterranean (Crete, Greece) were used to investigate patterns of both alpha and beta diversity in space and time. Copepod assemblages and environmental variables related to sediment characteristics, morphodynamics and food were studied over a year at four distinct habitats at each beach; the retention, resurgence and saturation zones of Salvat's intertidal scheme (midlittoral zone), and the surf zone of the sublittoral. Αlpha diversity analysis indicated similar species richness at both beaches when the whole 13-month data set was considered but was higher at the sheltered site when each sampling period was examined separately. Both beaches supported higher diversity in the sublittoral zone. Species richness increased seawards at the midlittoral zone of the sheltered site whereas, no pattern was evident at the exposed site, where the intense hydrodynamic conditions homogenized the sediments. Beta diversity increased markedly towards the sublittoral, indicating greater differences in alpha diversity between the sublittoral and the midlittoral zone. Species turnover was more variable at the exposed beach and at the most landward stations, where environmental conditions change often between extremes. A proportion of the variation in alpha diversity was explained by food availability at both beaches and additionally by grain size at the sheltered site. However, no environmental variable explained beta diversity patterns. Although the results of our study support the hypothesis of Multicausal Environmental Severity proposed for sandy beach macrofauna, we believe the classic Intermediate Disturbance Hypothesis is a more appropriate framework for the meiofauna communities of the studied sites.

  2. The effects of mixed algal diets on population growth, egg productivity and nutritional profiles in cyclopoid copepods (Thermocyclops hyalinus and Mesocyclops aspericornis

    Directory of Open Access Journals (Sweden)

    Kumar Vidhya

    2014-03-01

    Full Text Available This experiment was carried out to evaluate the effect of mixed algal diet on dietary profiles of copepods. The microalgae like Spirulina platensis, Chlorella vulgaris and Azolla pinnata were mass cultured in artificial medium for a period of 20 days, cells are harvested, dried, powdered and used as feed. The small freshwater cyclopoids Thermocyclops hyalinus were compared to Mesocyclops aspericornis a species of copepod genera commonly preferred by most of the fish larvae. Both species are easily maintained in culture, when fed with mixed algal diets of equal ratios (1:1:1. Biochemical composition, egg production ratios, growth performance and fatty acids profile of the two different species were analyzed after an experimental period of 15 days, all the nutritional values were found to be high and statistically variable. On the basis of biochemical composition, egg production ratio, growth performance, amino acids and fatty acids profile it is found that M. aspericornis was the suitable candidate for larval fish diets.

  3. Reverse genetics in the tide pool: knock-down of target gene expression via RNA interference in the copepod Tigriopus californicus.

    Science.gov (United States)

    Barreto, Felipe S; Schoville, Sean D; Burton, Ronald S

    2015-07-01

    Reverse genetic tools are essential for characterizing phenotypes of novel genes and testing functional hypotheses generated from next-generation sequencing studies. RNA interference (RNAi) has been a widely used technique for describing or quantifying physiological, developmental or behavioural roles of target genes by suppressing their expression. The marine intertidal copepod Tigriopus californicus has become an emerging model for evolutionary and physiological studies, but this species is not amenable to most genetic manipulation approaches. As crustaceans are susceptible to RNAi-mediated gene knock-down, we developed a simple method for delivery of gene-specific double-stranded RNA that results in significant suppression of target gene transcription levels. The protocol was examined on five genes of interest, and for each, at least 50% knock-down in expression was achieved. While knock-down levels did not reach 100% in any trial, a well-controlled experiment with one heat-shock gene showed unambiguously that such partial gene suppression may cause dramatic changes in phenotype. Copepods with suppressed expression of heat-shock protein beta 1 (hspb1) exhibited dramatically decreased tolerance to high temperatures, validating the importance of this gene during thermal stress, as proposed by a previous study. The application of this RNAi protocol in T. californicus will be invaluable for examining the role of genes putatively involved in reproductive isolation, mitochondrial function and local adaptation.

  4. Identification and developmental expression of the enzymes responsible for dopamine, histamine, octopamine and serotonin biosynthesis in the copepod crustacean Calanus finmarchicus.

    Science.gov (United States)

    Christie, Andrew E; Fontanilla, Tiana M; Roncalli, Vittoria; Cieslak, Matthew C; Lenz, Petra H

    2014-01-01

    Neurochemicals are likely to play key roles in physiological/behavioral control in the copepod crustacean Calanus finmarchicus, the biomass dominant zooplankton for much of the North Atlantic Ocean. Previously, a de novo assembled transcriptome consisting of 206,041 unique sequences was used to characterize the peptidergic signaling systems of Calanus. Here, this assembly was mined for transcripts encoding enzymes involved in amine biosynthesis. Using known Drosophila melanogaster proteins as templates, transcripts encoding putative Calanus homologs of tryptophan-phenylalanine hydroxylase (dopamine, octopamine and serotonin biosynthesis), tyrosine hydroxylase (dopamine biosynthesis), DOPA decarboxylase (dopamine and serotonin biosynthesis), histidine decarboxylase (histamine biosynthesis), tyrosine decarboxylase (octopamine biosynthesis), tyramine β-hydroxylase (octopamine biosynthesis) and tryptophan hydroxylase (serotonin biosynthesis) were identified. Reverse BLAST and domain analyses show that the proteins deduced from these transcripts possess sequence homology to and the structural hallmarks of their respective enzyme families. Developmental profiling revealed a remarkably consistent pattern of expression for all transcripts, with the highest levels of expression typically seen in the early nauplius and early copepodite. These expression patterns suggest roles for amines during development, particularly in the metamorphic transitions from embryo to nauplius and from nauplius to copepodite. Taken collectively, the data presented here lay a strong foundation for future gene-based studies of aminergic signaling in this and other copepod species, in particular assessment of the roles they may play in developmental control.

  5. [Construction of suppression subtractive hybridization (SSH) library of copepod Pseudodiaptomous annandalei and its ferritin cDNA cloning and differential expression under nickel stress].

    Science.gov (United States)

    Jiang, Jie-Lan; Wang, Gui-Zhong; Wu, Li-Sheng; Li, Shao-Jing

    2012-07-01

    To study the molecular response mechanisms of copepod to nickel stress, a suppression subtractive hybridization (SSH) cDNA library of Pseudodiaptomous annandalei under nickel stress was constructed by using SSH technique, and a total of 140 clones were randomly picked from the growing colonies and identified by PCR. The recombinant rate of the library was 98.6%, and the volume of the library was 1.12 x 10(6) cfu. After the recombinant plasmids were sequenced, a partial cDNA fragment of ferritin was recognized based on BLAST searches in NCBI, with a size of 859 bp and continuously encoding 170 amino acid residues. The semi-quantitative PCR results showed that the ferritin cDNA under 24 h nickel stress was distinctly up-regulated. The successful construction of the SSH library and the obtaining of ferritin cDNA fragment would supply basis for the further study of the molecular response mechanisms of copepod to nickel stress.

  6. Ultraviolet B radiation induces impaired lifecycle traits and modulates expression of cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus.

    Science.gov (United States)

    Puthumana, Jayesh; Lee, Min-Chul; Park, Jun Chul; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon; Lee, Jae-Seong

    2017-03-01

    To evaluate the effects of ultraviolet B (UV-B) radiation at the developmental, reproductive, and molecular levels in aquatic invertebrates, we measured UV-B-induced acute toxicity, impairments in developmental and reproductive traits, and UV-B interaction with the entire family of cytochrome P450 (CYP) genes in the intertidal benthic copepod Tigriopus japonicus. We found a significant, dose-dependent reduction (PB induced toxicity. Low-dose UV-B (1.5kJ/m(2)) induced developmental delays, and higher doses (6-18kJ/m(2)) caused reproductive impairments in ovigerous females. The significant up-regulation of CYP genes belonging to clans 2/3/MT/4/20 in T. japonicus exposed to UV-B (12kJ/m(2)) confirmed molecular interaction between UV-B and CYP genes. Moreover, orphan CYPs, such as CYP20A1, provide good insight on the deorphanization of invertebrate CYPs. Overall, these results demonstrate the involvement of UV-B radiation in the expression of all the CYP genes in T. japonicus and their susceptibility to UV-B radiation. This will provide a better understanding of the mechanistic effects of UV-B in copepods through the predicted AhR-mediated up-regulation of CYP genes.

  7. Video Plankton Recorder estimates of copepod, pteropod and larvacean distributions from a stratified region of Georges Bank with comparative measurements from a MOCNESS sampler

    Science.gov (United States)

    Benfield, Mark C.; Davis, Cabell S.; Wiebe, Peter H.; Gallager, Scott M.; Gregory Lough, R.; Copley, Nancy J.

    A two-vessel exercise was conducted over the southern flank of Georges Bank during the onset of vernal stratification in May 1992. The Video Plankton Recorder (VPR), a towed video system, was used to map out the fine-scale distributions of zooplankton to a depth of 70 m along a trackline which described a regular grid (3.5 × 4.5 km) in Lagrangian space. A second vessel following a parallel course conducted Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) sampling during the last section of the grid, which provided an opportunity to compare data from the two systems. Both the VPR and the MOCNESS provided similar data on the taxonomic composition of the plankton which was numerically dominated by copepods ( Calanus, Pseudocalanus, Oithona), pteropods ( Limacina) and larvaceans ( Oikopleura). The absence of rare (gelatinous taxa were undersampled by the MOCNESS. Estimates of copepod and pteropod concentrations were comparable for the two gear types. While the species composition of the plankton did not change statistically along the grid, abundances of the dominant taxa varied along the transect and each taxon demonstrated pronounced fine-scale vertical patterns that appeared to be related to hydrographic features. The VPR represents a powerful tool for rapid surveys of the micro- to fine-scale structure of zooplankton assemblages either alone, or in conjunction with other sampling techniques.

  8. Estimating cyclopoid copepod species richness and geographical distribution (Crustacea across a large hydrographical basin: comparing between samples from water column (plankton and macrophyte stands

    Directory of Open Access Journals (Sweden)

    Gilmar Perbiche-Neves

    2014-06-01

    Full Text Available Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the "La Plata" River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone.

  9. A study on the zooplankton of the Burhabalanga Estuary, Orissa Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, Neelam; Chatterji, A; Madhupratap, M.

    the stations during October 1991 as a result of a mysid swarm. Copepoda was generally the most abundant group. The copepods Pseudodiaptomus bowmani, P. sewelli, Acartia tropica and A. bowmani are recorded for the first time from the east coast of India....

  10. BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae-Sik; Han, Jeonghoon; Won, Eun-Ji; Kim, Duck-Hyun; Jeong, Chang-Bum [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Hwang, Un-Ki [Marine Ecological Risk Assessment Center, West Sea Fisheries Research Institute, National Fisheries Research & Development Institute, Incheon 46083 (Korea, Republic of); Zhou, Bingsheng [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Choe, Joonho [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419 (Korea, Republic of)

    2016-08-15

    Highlights: • The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47. • Expression profiles of nearly all NR genes were the highest at naupliar stages 5–6. • USP, HR96, and FTZ-F1 genes showed significant sex differences (P < 0.05) over different developmental stages. • NR gene expression patterns showed significant decreases (P<0.05) in response to BDE-47. • BDE-47 leads to molting and metamorphosis retardation and suppresses transcription of NR genes. - Abstract: 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g. developmental retardation) in ecdysozoa, the effects of BDE-47 on transcription of ecdysteroid signaling pathway-involved-nuclear receptor (NR) genes and metamorphosis-related genes have not been examined in copepods. To examine the deleterious effect of BDE-47 on copepod molting and metamorphosis, BDE-47 was exposed to the harpacticoid copepod Tigriopus japonicus, followed by monitoring developmental retardation and transcriptional alteration of NR genes. The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47 and the agricultural insecticide gamma-hexachlorocyclohexane. Conversely, the ecdysteroid agonist ponasterone A (PoA) led to decreased molting and metamorphosis time (P < 0.05) from the nauplius stage to the adult stage. In particular, expression profiles of all NR genes were the highest at naupliar stages 5–6 except for SVP, FTZ-F1, and HR96 genes. Nuclear receptor USP, HR96, and FTZ-F1 genes also showed significant sex differences (P < 0.05) in gene expression levels over different developmental stages, indicating that these genes may be involved in vitellogenesis. NR gene expression patterns showed significant decreases (P < 0.05) in response to BDE-47 exposure, implying that molting and metamorphosis retardation is likely associated with NR gene expression. In summary, BDE-47

  11. Adverse effects of microplastics and oxidative stress-induced MAPK/Nrf2 pathway-mediated defense mechanisms in the marine copepod Paracyclopina nana.

    Science.gov (United States)

    Jeong, Chang-Bum; Kang, Hye-Min; Lee, Min-Chul; Kim, Duck-Hyun; Han, Jeonghoon; Hwang, Dae-Sik; Souissi, Sami; Lee, Su-Jae; Shin, Kyung-Hoon; Park, Heum Gi; Lee, Jae-Seong

    2017-01-24

    Microplastic pollution causes a major concern in the marine environment due to their worldwide distribution, persistence, and adverse effects of these pollutants in the marine ecosystem. Despite its global presence, there is still a lack of information on the effect of microplastics on marine organisms at the molecular level. Herein we demonstrated ingestion and egestion of nano- (0.05 μm) and micro-sized (0.5 and 6 μm) polystyrene microbeads in the marine copepod Paracyclopina nana, and examined molecular responses to exposure to microbeads with in vivo endpoints such as growth rate and fecundity. Also, we proposed an adverse outcome pathway for microplastic exposure that covers molecular and individual levels. This study provides the first insight into the mode of action in terms of microplastic-induced oxidative stress and related signaling pathways in P. nana.

  12. Passive dosing of triclosan in multi-generation tests with copepods - Stable exposure concentrations and effects at the low µg l-1 range

    DEFF Research Database (Denmark)

    Ribbenstedt, Anton; Mustajärvi, Lukas; Breitholtz, Magnus

    2016-01-01

    Ecotoxicity testing is a crucial component of chemical risk assessment. Still, due to methodological difficulties related to controlling exposure concentrations over time, data on long-term effects of organic chemicals at low concentrations are limited. The aim of the present study was therefore...... to test the applicability of passive dosing to maintain stable concentrations of the organochlorine bacteriocide triclosan in the water phase during a 6-week multi-generation population development test with the harpacticoid copepod Nitocra spinipes. Triclosan was loaded into silicone (1000 mg), which...... was used as passive dosing phase in the exposure vials. The distribution ratio for triclosan between silicone and water (Dsilicone-water ) was 10466 ± 1927. A population development test was conducted at three concentration levels of triclosan that were measured to be 3-5 µg L(-1) , 7-11 µg L(-1) and 16...

  13. Adverse effects of microplastics and oxidative stress-induced MAPK/Nrf2 pathway-mediated defense mechanisms in the marine copepod Paracyclopina nana

    Science.gov (United States)

    Jeong, Chang-Bum; Kang, Hye-Min; Lee, Min-Chul; Kim, Duck-Hyun; Han, Jeonghoon; Hwang, Dae-Sik; Souissi, Sami; Lee, Su-Jae; Shin, Kyung-Hoon; Park, Heum Gi; Lee, Jae-Seong

    2017-01-01

    Microplastic pollution causes a major concern in the marine environment due to their worldwide distribution, persistence, and adverse effects of these pollutants in the marine ecosystem. Despite its global presence, there is still a lack of information on the effect of microplastics on marine organisms at the molecular level. Herein we demonstrated ingestion and egestion of nano- (0.05 μm) and micro-sized (0.5 and 6 μm) polystyrene microbeads in the marine copepod Paracyclopina nana, and examined molecular responses to exposure to microbeads with in vivo endpoints such as growth rate and fecundity. Also, we proposed an adverse outcome pathway for microplastic exposure that covers molecular and individual levels. This study provides the first insight into the mode of action in terms of microplastic-induced oxidative stress and related signaling pathways in P. nana.

  14. Passive dosing of triclosan in multi-generation tests with copepods - Stable exposure concentrations and effects at the low µg l-1 range

    DEFF Research Database (Denmark)

    Ribbenstedt, Anton; Mustajärvi, Lukas; Breitholtz, Magnus;

    2016-01-01

    to test the applicability of passive dosing to maintain stable concentrations of the organochlorine bacteriocide triclosan in the water phase during a 6-week multi-generation population development test with the harpacticoid copepod Nitocra spinipes. Triclosan was loaded into silicone (1000 mg), which...... was used as passive dosing phase in the exposure vials. The distribution ratio for triclosan between silicone and water (Dsilicone-water ) was 10466 ± 1927. A population development test was conducted at three concentration levels of triclosan that were measured to be 3-5 µg L(-1) , 7-11 µg L(-1) and 16...... exerted on juvenile development. Progressively lower development index values in the populations exposed to increasing triclosan concentrations suggest developmental retardation. Our results further stress the need for chronic exposure during ecotoxicity testing in chemical risk assessment as even...

  15. Identification of Hox genes and rearrangements within the single homeobox (Hox) cluster (192.8 kb) of the cyclopoid copepod (Paracyclopina nana).

    Science.gov (United States)

    Kim, Hui-Su; Kim, Bo-Mi; Lee, Bo-Young; Souissi, Sami; Park, Heum Gi; Lee, Jae-Seong

    2016-03-01

    We report the first identification of the entire complement of the eight typical homeobox (hox) genes (lab, pb, Dfd, scr, antp, ubx, Abd-A, and Abd-B) and the ftz gene in a 192.8 kb region in the cyclopoid copepod Paracyclopina nana. A Hox3 gene ortholog was not present in the P. nana hox gene cluster, while the P. nana Dfd gene was transcribed in the opposite direction to the Daphnia pulex Dfd gene, but in the same direction as the Dfd genes of the fruit fly Drosophila melanogaster and red flour beetle Tribolium castaneum. The location of the lab and pb genes was switched in the P. nana hox cluster, while the order of the remaining hox genes was generally conserved with those of other arthropods. J. Exp. Zool. (Mol. Dev. Evol.) 9999B:XX-XX, 2016. © 2016 Wiley Periodicals, Inc.

  16. Investigating the molecular basis of local adaptation to thermal stress: population differences in gene expression across the transcriptome of the copepod Tigriopus californicus

    Directory of Open Access Journals (Sweden)

    Schoville Sean D

    2012-09-01

    Full Text Available Abstract Background Geographic variation in the thermal environment impacts a broad range of biochemical and physiological processes and can be a major selective force leading to local population adaptation. In the intertidal copepod Tigriopus californicus, populations along the coast of California show differences in thermal tolerance that are consistent with adaptation, i.e., southern populations withstand thermal stresses that are lethal to northern populations. To understand the genetic basis of these physiological differences, we use an RNA-seq approach to compare genome-wide patterns of gene expression in two populations known to differ in thermal tolerance. Results Observed differences in gene expression between the southern (San Diego and the northern (Santa Cruz populations included both the number of affected loci as well as the identity of these loci. However, the most pronounced differences concerned the amplitude of up-regulation of genes producing heat shock proteins (Hsps and genes involved in ubiquitination and proteolysis. Among the hsp genes, orthologous pairs show markedly different thermal responses as the amplitude of hsp response was greatly elevated in the San Diego population, most notably in members of the hsp70 gene family. There was no evidence of accelerated evolution at the sequence level for hsp genes. Among other sets of genes, cuticle genes were up-regulated in SD but down-regulated in SC, and mitochondrial genes were down-regulated in both populations. Conclusions Marked changes in gene expression were observed in response to acute sub-lethal thermal stress in the copepod T. californicus. Although some qualitative differences were observed between populations, the most pronounced differences involved the magnitude of induction of numerous hsp and ubiquitin genes. These differences in gene expression suggest that evolutionary divergence in the regulatory pathway(s involved in acute temperature stress may offer at

  17. Ecdysone receptor (EcR) and ultraspiracle (USP) genes from the cyclopoid copepod Paracyclopina nana: Identification and expression in response to water accommodated fractions (WAFs).

    Science.gov (United States)

    Puthumana, Jayesh; Lee, Min-Chul; Han, Jeonghoon; Kim, Hui-Su; Hwang, Dae-Sik; Lee, Jae-Seong

    2017-02-01

    Ecdysteroid hormones are pivotal in the development, growth, and molting of arthropods, and the hormone pathway is triggered by binding ecdysteroid to a heterodimer of the two nuclear receptors; ecdysone receptors (EcR) and ultraspiracle (USP). We have characterized EcR and USP genes, and their 5'-untranslated region (5'-UTR) from the copepod Paracyclopina nana, and studied mRNA transcription levels in post-embryonic stages and in response to water accommodated fractions (WAFs) of crude oil. The open reading frames (ORF) of EcR and USP were 1470 and 1287bp that encoded 490 and 429 amino acids with molecular weight of 121.18 and 105.03kDa, respectively. Also, a well conserved DNA-binding domain (DBD) and ligand-binding domain (LBD) were identified which confirmed by phylogenetic analysis. Messenger RNA transcriptional levels of EcR and USP were developmental stage-specific in early post-embryonic stages (N3-4). However, an evoked expression of USP was observed throughout copepodid stage and in adult females. WAFs (40 and 80%) were acted as an ecdysone agonist in P. nana, and elicited the mRNA transcription levels in adults. Developmental stage-specific transcriptional activation of EcR and USP in response to WAFs was observed. USP gene was down-regulated in the nauplius in response to WAF, whereas up-regulation of USP was observed in the adults. This study represents the first data of molecular elucidation of EcR and USP genes and their regulatory elements from P. nana and the developmental stage specific expression in response to WAFs, which can be used as potential biomarkers for environmental stressors with ecotoxicological evaluations in copepods.

  18. Spring production of Calanus finmarchicus at the Iceland-Scotland Ridge

    DEFF Research Database (Denmark)

    Jonasdottir, Sigrun; Richardson, K.; Heath, M.R.;

    2008-01-01

    Distribution and reproduction activity of the calanoid copepod Calanus finmarchicus were studied in the waters between Scotland and Iceland in April 1997 during the expected time of the animals' ascent to surface waters following diapause. Ascent was taking place on both sides of the Iceland...

  19. Chitinous palynomorphs and palynodebris representing crustacean exoskeleton remains from sediments of the Banda Sea (Indonesia)

    NARCIS (Netherlands)

    Waveren, van I.M.

    1994-01-01

    Palynological residues from surface sediments in the Banda Sea (Indonesia) are characterised by the presence of chitinous palynomorph types that can be correlated with exoskeletons of crustaceans, notably calanoid copepods. A series of 27 palynomorph types are described and informally categorised. A

  20. Groundwater crustaceans of Spain, 13 (Copepoda Calanoida)

    NARCIS (Netherlands)

    Bowman, Thomas E.

    1990-01-01

    Two calanoid copepods were collected from groundwaters in Spain by the University of Amsterdam Expeditions in 1983—84 and 1985. Copidodiaptomus numidicus was found in southwestern Spain, in provincias Huelva and Sevilla. Mixodiaptomus laciniatus, previously known in Spain only from the Pyrenees, was

  1. A lasting legacy for the Baltic and North Sea GLOBEC Germany program

    DEFF Research Database (Denmark)

    Peck, M.A.; Dutz, Jörg; Voss, R.

    2012-01-01

    This preface introduces four manuscripts that form a special theme section of the GLOBEC Germany program within Progress in Oceanography. The four manuscripts link changes in physical forcing to the trophodynamic structure and function of the Baltic and North Seas. The target species of GLOBEC...... Germany included various species of calanoid copepods and a small pelagic fish (Sprattus sprattus)...

  2. Species Composition and Diversity of Planktonic Copepods in Culture Zone of Eucheuma%麒麟菜养殖区海域浮游桡足类种类组成与多样性

    Institute of Scientific and Technical Information of China (English)

    张钰; 王仁恩; 黄勃; 杨文杰

    2012-01-01

    [目的]研究麒麟菜养殖区海域浮游桡足类种类组成与多样性.[方法]于2011年1~12月对麒麟菜养殖区海尾镇海域进行生态环境调查,分析麒麟菜养殖海区浮游桡足类种类组成与多样性,并对其与季节及麒麟菜养殖的关系进行了初步探讨.[结果]此次调查期间共出现了浮游桡足类56种,其中有13种是全年出现的,以夏、秋季较多,春、冬较少;四季共出现优势桡足类9种,出现的生态类型有近岸低盐型、广温广盐型、高温广盐型,其中以近岸低盐类型占主导.麒麟菜丰富区域浮游桡足类种类多样性高于麒麟菜不丰富区域.[结论]麒麟菜养殖和季节变化对浮游桡足类多样性有一定的影响.%[Objective] The research aimed to study the species composition and diversity of planktonic copepods in culture zone of Eucheuma. [Method] The ecological environment of sea area in Haiwei Town of culture zone of Eucheuma was surveyed during 2011.1 -2011. The species composition and diversity of planktonic copepod in culture zone of Eucheuma were analyzed and its relationship with the culture of Eucheuma was preliminarily discussed. [Result] 56 species of Copepod were identified in this survey. Among them, 13 species occurred yearly. More species of Copepod were found in summer and autumn, while less species were found in spring and winter. 9 dominant species found in 4 seasons were neritic and hypohaline type, eurythermal and euryhaline type , hyperthermal and euryhaline type. The dominant ecological type was neritic and hypohaline type . The diversity of the planktonic eopepods in richer region in the culture zone of Eucheuma was higher. [Conclusion] The diversity of Copepods were affected by Eucheuma culture and seasonal variation.

  3. Amberstripe scad Decapterus muroadsi (Carangidae) fish ingest blue microplastics resembling their copepod prey along the coast of Rapa Nui (Easter Island) in the South Pacific subtropical gyre.

    Science.gov (United States)

    Ory, Nicolas Christian; Sobral, Paula; Ferreira, Joana Lia; Thiel, Martin

    2017-05-15

    An increasing number of studies have described the presence of microplastics (≤5mm) in many different fish species, raising ecological concerns. The factors influencing the ingestion of microplastics by fish remain unclear despite their importance to a better understanding of the routes of microplastics through marine food webs. Here, we compare microplastics and planktonic organisms in surface waters and as food items of 20 Amberstripe scads (Decapterus muroadsi) captured along the coast of Rapa Nui (Easter Island) to assess the hypothesis that fish ingest microplastics resembling their natural prey. Sixteen (80%) of the scad had ingested one to five microplastics, mainly blue polyethylene fragments that were similar in colour and size to blue copepod species consumed by the same fish. These results suggest that planktivorous fish, as a consequence of their feeding behaviour as visual predators, are directly exposed to floating microplastics. This threat may be exacerbated in the clear oceanic waters of the subtropical gyres, where anthropogenic litter accumulates in great quantity. Our study highlights the menace of microplastic contamination on the integrity of fragile remote ecosystems and the urgent need for efficient plastic waste management.

  4. Screening of candidate genes encoding proteins expressed in pectoral fins of fugu Takifugu rubripes, in relation to habitat site of parasitic copepod Caligus fugu, using suppression subtractive hybridization.

    Science.gov (United States)

    Tasumi, Satoshi; Norshida, Ismail; Boxshall, Geoffrey A; Kikuchi, Kiyoshi; Suzuki, Yuzuru; Ohtsuka, Susumu

    2015-05-01

    Caligus fugu is a parasitic copepod specific to the tetraodontid genus Takifugu including the commercially important Takifugu rubripes. Despite the rapid accumulation of knowledge on other aspects of its biology, the host and settlement-site recognition mechanisms of this parasite are not yet well understood. Since the infective copepodid stage shows preferential site selection in attaching to the fins, we considered it likely that the copepodid recognizes chemical cues released or leaking from the fins, and/or transmembrane protein present on the fins. To isolate molecules potentially related to attachment site specificity, we applied suppression subtractive hybridization (SSH) PCR by identifying genes expressed more highly in pectoral fins of T. rubripes than in the body surface skin. We sequenced plasmid DNA from 392 clones in a SSH library. The number of non-redundant sequences was 276, which included 135 sequences located on 117 annotated genes and 141 located in positions where no genes had been annotated. We characterized those annotated genes on the basis of gene ontology terms, and found that 46 of the identified genes encode secreted proteins, enzymes or membrane proteins. Among them nine showed higher expression in the pectoral fins than in the skin. These could be candidate genes for involvement in behavioral mechanisms related to the site specificity shown by the infective copepodids of C. fugu.

  5. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana.

    Science.gov (United States)

    Won, Eun-Ji; Han, Jeonghoon; Lee, Yeonjung; Kumar, K Suresh; Shin, Kyung-Hoon; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

    2015-08-01

    To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0-3kJ/m(2)) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7-87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (Pnana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1kJ/m(2) of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana.

  6. Genome-wide identification of ATP-binding cassette (ABC) transporters and their roles in response to polycyclic aromatic hydrocarbons (PAHs) in the copepod Paracyclopina nana.

    Science.gov (United States)

    Jeong, Chang-Bum; Kim, Duck-Hyun; Kang, Hye-Min; Lee, Young Hwan; Kim, Hui-Su; Kim, Il-Chan; Lee, Jae-Seong

    2017-02-01

    The ATP-binding cassette (ABC) protein superfamily is one of the largest gene families and is highly conserved in all domains. The ABC proteins play roles in several biological processes, including multi-xenobiotic resistance (MXR), by functioning as transporters in the cellular membrane. They also mediate the cellular efflux of a wide range of substrates against concentration gradients. In this study, 37 ABC genes belonging to eight distinct subfamilies were identified in the marine copepod Paracyclopina nana and annotated based on a phylogenetic analysis. Also, the functions of P-glycoproteins (P-gp) and multidrug resistance-associated proteins (MRPs), conferring MXR, were verified using fluorescent substrates and specific inhibitors. The activities of MXR-mediated ABC proteins and their transcriptional level were examined in response to polyaromatic hydrocarbons (PAHs), main components of the water-accommodated fraction. This study increases the understanding of the protective role of MXR in response to PAHs over the comparative evolution of ABC gene families.

  7. Influence of ocean acidification on plankton community structure during a winter-to-summer succession: An imaging approach indicates that copepods can benefit from elevated CO2 via indirect food web effects

    Science.gov (United States)

    Taucher, Jan; Haunost, Mathias; Boxhammer, Tim; Bach, Lennart T.; Algueró-Muñiz, María; Riebesell, Ulf

    2017-01-01

    Plankton communities play a key role in the marine food web and are expected to be highly sensitive to ongoing environmental change. Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. These changes–summarized by the term ocean acidification (OA)–can significantly affect the physiology of planktonic organisms. However, studies on the response of entire plankton communities to OA, which also include indirect effects via food-web interactions, are still relatively rare. Thus, it is presently unclear how OA could affect the functioning of entire ecosystems and biogeochemical element cycles. In this study, we report from a long-term in situ mesocosm experiment, where we investigated the response of natural plankton communities in temperate waters (Gullmarfjord, Sweden) to elevated CO2 concentrations and OA as expected for the end of the century (~760 μatm pCO2). Based on a plankton-imaging approach, we examined size structure, community composition and food web characteristics of the whole plankton assemblage, ranging from picoplankton to mesozooplankton, during an entire winter-to-summer succession. The plankton imaging system revealed pronounced temporal changes in the size structure of the copepod community over the course of the plankton bloom. The observed shift towards smaller individuals resulted in an overall decrease of copepod biomass by 25%, despite increasing numerical abundances. Furthermore, we observed distinct effects of elevated CO2 on biomass and size structure of the entire plankton community. Notably, the biomass of copepods, dominated by Pseudocalanus acuspes, displayed a tendency towards elevated biomass by up to 30–40% under simulated ocean acidification. This effect was significant for certain copepod size classes and was most likely driven by CO2-stimulated responses of primary producers and a complex interplay of trophic interactions that allowed this

  8. Cryptic or pseudocryptic: can morphological methods inform copepod taxonomy? An analysis of publications and a case study of the Eurytemora affinis species complex.

    Science.gov (United States)

    Lajus, Dmitry; Sukhikh, Natalia; Alekseev, Victor

    2015-06-01

    , morphological techniques have great potential in determining copepod taxonomy.

  9. Seasonal variation in fatty acid composition of seston and the copepod Calanus sinicus (Brodsky, 1962) in Jiaozhou Bay and its trophic implications

    Institute of Scientific and Technical Information of China (English)

    LIU Mengtan; LI Chaolun; SUN Song

    2011-01-01

    The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay.Principal component analysis was carried out to ordinate the fatty acid patterns of seston in stations and months.The results showed that diatoms were most abundant in the phytoplankton at station A5 (located in the northwest of the bay:36°9′N,120°20′E) and least abundant at station D7 (located outside of the bay:35°59′N,120°26′E).By contrast,dinoflagellates were most abundant at station D7 and least abundant at station A5.According to the annual variations of 16:1 ω7 and 18:4ω3/16:1ω7,diatoms flourished mainly in spring and summer,while dinoflagellates bloomed exclusively in summer.A distinctive feature of the fatty acid composition of C.sinicus was the prevalence of 20:5ω3and 22:6ω3.The higher content of 16:1ω7 over 18:4ω3 in females indicated that diatoms contributed more than dinoflagellates to the diet of C.sinicus.The feeding intensity of C.sinicus on diatoms was higher in spring and autumn than in other seasons.The herbivorous indicators 20:1 and 22:1 were comparatively low,suggesting that besides phytoplankton,C.sinicus might feed on a wider range of particles including organic detritus,bacteria and small copepods.

  10. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana

    Energy Technology Data Exchange (ETDEWEB)

    Won, Eun-Ji; Han, Jeonghoon [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Yeonjung; Kumar, K. Suresh; Shin, Kyung-Hoon [Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Su-Jae [Department of Life Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Heum Gi, E-mail: hgpark@gwnu.ac.kr [Department of Marine Resource Development, College of Life Sciences, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-08-15

    Highlights: • UV-B radiation induced a significant reduction of the re-brooding rate of ovigerous females. • A dose-dependent decrease in food ingestion and the rate of assimilation to the body upon UV radiation. • Expression of base excision repair-associated and hsp chaperoning genes was significantly increased upon UV radiation in P. nana. - Abstract: To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0–3 kJ/m{sup 2}) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7–87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P < 0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1 kJ/m{sup 2} of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana.

  11. Cryptic Species or Inadequate Taxonomy? Implementation of 2D Geometric Morphometrics Based on Integumental Organs as Landmarks for Delimitation and Description of Copepod Taxa.

    Science.gov (United States)

    Karanovic, Tomislav; Djurakic, Marko; Eberhard, Stefan M

    2016-03-01

    Discovery of cryptic species using molecular tools has become common in many animal groups but it is rarely accompanied by morphological revision, creating ongoing problems in taxonomy and conservation. In copepods, cryptic species have been discovered in most groups where fast-evolving molecular markers were employed. In this study at Yeelirrie in Western Australia we investigate a subterranean species complex belonging to the harpacticoid genus Schizopera Sars, 1905, using both the barcoding mitochondrial COI gene and landmark-based two-dimensional geometric morphometrics. Integumental organs (sensilla and pores) are used as landmarks for the first time in any crustacean group. Complete congruence between DNA-based species delimitation and relative position of integumental organs in two independent morphological structures suggests the existence of three distinct evolutionary units. We describe two of them as new species, employing a condensed taxonomic format appropriate for cryptic species. We argue that many supposedly cryptic species might not be cryptic if researchers focus on analyzing morphological structures with multivariate tools that explicitly take into account geometry of the phenotype. A perceived supremacy of molecular methods in detecting cryptic species is in our view a consequence of disparity of investment and unexploited recent advancements in morphometrics among taxonomists. Our study shows that morphometric data alone could be used to find diagnostic morphological traits and gives hope to anyone studying small animals with a hard integument or shell, especially opening the door to assessing fossil diversity and rich museum collections. We expect that simultaneous use of molecular tools with geometry-oriented morphometrics may yield faster formal description of species. Decrypted species in this study are a good example for urgency of formal descriptions, as they display short-range endemism in small groundwater calcrete aquifers in a

  12. The Nutrition of Marine Copepods and Its Application in Fish, Shrimp and Crab Larvae Culture%海水桡足类的营养及在鱼、虾、蟹幼体培育中的应用

    Institute of Scientific and Technical Information of China (English)

    蒋建斌; 陆建学

    2012-01-01

    Marine copepods, which are important food for marine commercial fishes and crustaceans, play a very important role in marine food chain and ecosystem. They are also used as a source of living foods for fishes, shrimps and crabs larvae during the artificial propagation of aquatic animals. Studies on nutrition of marine copepods and its application effects are significant in improving metamorphosis rate, survival rate, larvae quality and artificial breeding success rate.%海水桡足类在海洋食物网和生态系统中具有重要的地位,是各种海洋经济鱼类和甲壳类的重要饵料,也是经济水产动物人工育苗阶段的优质活饵料源。研究海水桡足类营养和应用效果,对提高海水鱼、虾、蟹类幼体变态率、成活率、苗种质量和育苗成功率具有重要的意义。

  13. ABUNDANCE AND BIOMASS OF COPEPOD NAUPLII AND CILIATES IN JIAOZHOU BAY%胶州湾桡足类幼虫和浮游生纤毛虫的丰度与生物量

    Institute of Scientific and Technical Information of China (English)

    张武昌; 王荣

    2001-01-01

    This paper presents data of ciliates and copepod nauplii abundance and biomass from eight cruises (September, December, 1997; February, April, August, November, 1998; February, May, 1999) in Jiaozhou Bay. Water samples were taken by 2L Niskin Bottles at ten stations during every cruise. One liter water was preserved in plastic bottle with Lugol's (1%). The sample scheme of water layer was surface, middle and bottom according to water depth. The samples were examined with the method of Utermohl (1958) one month after sampling. Carbon:volumn ratio was 0.05 pgC/μm3 for copepod nauplii (Mullin, 1969), 0.19pgC/μm3 for ciliates (Putt et al, 1989). Body volume of tintinnids was assumed to be 50% of that of the lorica (Beers et al, 1969).   Copepod nauplii dominated in September 1997. The aloricate oligotrichous ciliates were dominant through December 1997 to February 1999. Tintinnids dominated in May 1999. The maximum abundance of copepod nauplii, aloricate ciliates and tintinnids were 850 (August, 1998), 21300 (August, 1998) and 1720 ind/L (May, 1999) respectively. The total abundance of the above three in the surface layer was 10—22350 ind/L, with larger abundance in the inner part of the bay. There was no obvious trend in the vertical distribution. The total biomass of copepod nauplii, aloricate ciliates and tintinnids in the surface layer was in the range of 0.10—380.27μgC/L, water column biomass 0.20—1426.02mgC/m2.%1997年9月、12月,1998年2月、4月、8月、11月以及1999年2月和5月在胶州湾采集桡足类幼虫和浮游生纤毛虫的样品。样品用Lugol's试剂固定(最后浓度1%),用显微镜计数桡足类幼虫和浮游生纤毛虫的丰度,并计算总生物量(表层生物量和水体生物量)。桡足类幼虫、无壳纤毛虫和砂壳纤毛虫的最大丰度分别为850ind/L(1998年8月)、21300ind/L(1998年8月)和1720ind/L(1999年5月)。表层的总丰度为10—22630ind/L,水平分布湾内比湾外多。表层纤

  14. Gene expression in Atlantic salmon skin in response to infection with the parasitic copepod Lepeophtheirus salmonis, cortisol implant, and their combination

    Directory of Open Access Journals (Sweden)

    Krasnov Aleksei

    2012-04-01

    Full Text Available Abstract Background The salmon louse is an ectoparasitic copepod that causes major economic losses in the aquaculture industry of Atlantic salmon. This host displays a high level of susceptibility to lice which can be accounted for by several factors including stress. In addition, the parasite itself acts as a potent stressor of the host, and outcomes of infection can depend on biotic and abiotic factors that stimulate production of cortisol. Consequently, examination of responses to infection with this parasite, in addition to stress hormone regulation in Atlantic salmon, is vital for better understanding of the host pathogen interaction. Results Atlantic salmon post smolts were organised into four experimental groups: lice + cortisol, lice + placebo, no lice + cortisol, no lice + placebo. Infection levels were equal in both treatments upon termination of the experiment. Gene expression changes in skin were assessed with 21 k oligonucleotide microarray and qPCR at the chalimus stage 18 days post infection at 9°C. The transcriptomic effects of hormone treatment were significantly greater than lice-infection induced changes. Cortisol stimulated expression of genes involved in metabolism of steroids and amino acids, chaperones, responses to oxidative stress and eicosanoid metabolism and suppressed genes related to antigen presentation, B and T cells, antiviral and inflammatory responses. Cortisol and lice equally down-regulated a large panel of motor proteins that can be important for wound contraction. Cortisol also suppressed multiple genes involved in wound healing, parts of which were activated by the parasite. Down-regulation of collagens and other structural proteins was in parallel with the induction of proteinases that degrade extracellular matrix (MMP9 and MMP13. Cortisol reduced expression of genes encoding proteins involved in formation of various tissue structures, regulators of cell differentiation and growth factors. Conclusions

  15. 臭氧对桡足类浮游动物的预氧化效能及灭活机理%Pre-oxidation Effect and Inactivation Mechanism of Copepod Zooplankton by Ozone

    Institute of Scientific and Technical Information of China (English)

    张健; 颜勇; 谢美萍; 林涛

    2012-01-01

    桡足类浮游动物存在于饮用水水源中,对饮用水安全以及人类健康构成了潜在威胁.以剑水蚤为研究对象,研究了臭氧对桡足类浮游动物的预氧化效果及其影响因素,探讨臭氧对桡足类浮游动物的灭活机理.结果表明,在低浓度、短接触时间下臭氧对浮游动物的灭活效率相对较低.臭氧的除蚤效率受pH值的影响较小,但随着有机物含量的增加而降低.电镜扫描显示,经臭氧氧化后剑水蚤体表发生了明显的皱缩现象.三维荧光光谱扫描发现,臭氧使剑水蚤体内细胞结构遭到破坏,在膜的渗透压下会有少量蛋白质外泄,但在有限的接触时间内臭氧的破坏能力有限,因此有必要进行后续消毒控制.%The presence of copepod zooplankton in drinking water sources poses potential threats to the safety of drinking water and human health. The prc-oxidation effect of copepod zooplankton ( Cyclops) by ozone and its influencing factors were studied. The inactivation mechanism of copepod zooplankton by ozone was analyzed. The experimental results showed that Cyclops inactivation rate was low at low ozone concentration and short contact time. pH almost had no effect on Cyclops inactivation rate. The inactivation rate decreased with the increase of organic content. The results of electron microscope showed the phenomenon of shrinkage on the body surface of Cyclops. In addition, three-dimensional fluorescence spectrum scanning showed that the cell structure of Cyclops was destroyed by ozone, and a little internal protein leaked out due to the membrane osmotic pressure. However, ozone destruction capacity is limited in the limited contact time. Subsequent disinfection control is necessary.

  16. Egg production rates of the copepod Calanus marshallae in relation to seasonal and interannual variations in microplankton biomass and species composition in the coastal upwelling zone off Oregon, USA

    Science.gov (United States)

    Peterson, William T.; Du, Xiuning

    2015-11-01

    In this study, we assessed trophic interactions between microplankton and copepods by studying the functional response of egg production rates (EPR; eggs female-1 day-1) of the copepod Calanus marshallae to variations in microplankton biomass, species composition and community structure. Female C. marshallae and phytoplankton water samples were collected biweekly at an inner-shelf station off Newport, Oregon USA for four years, 2011-2014, during which a total of 1213 female C. marshallae were incubated in 63 experiments. On average, 80% of the females spawned with an overall mean EPR of 30.4. EPRs in spring (Apr-May, average of 40.2) were significantly higher than summer (Jun-Oct; 26.4). EPRs were intermediate in winter (Jan-Feb; 32.5). Interannually, EPRs were significantly higher in 2014 than 2011 and 2012. Total chlorophyll a (Chl a) concentration and diatom abundance both were significantly higher in summer while no seasonal differences were found in abundance of dinoflagellates, ciliates or Cryptophytes. Although total Chl a showed no interannual differences in bulk biomass of phytoplankton, community structure analysis indicated differences among years. More diverse diatom communities were observed in 2013 and 2014 compared to 2011 and 2012. Relationships between EPR and potential food variables (phytoplankton and ciliates) were significant by season: a hyperbolic functional response was found between EPR and total Chl a in winter-spring and summer, separately, and between EPR and ciliate abundance in winter-spring; a linear model fit best the functional response of EPR to diatom abundance in summer. The estimate of potential population recruitment rate (the number of females × EPR; eggs day-1 m-2) was highest in spring (Apr-May), and annually was highest in 2013 (11,660), followed by 2011 (6209), 2012 (3172) and 2014 (1480). Our observations of in situ EPR were far higher than published laboratory rates of 23.5, calling into question our past laboratory

  17. Comparative Study on the Acute Toxicity of Ocean Acidification Driven by CO2 and HCI on Several Marine Copepods%二氧化碳酸化和盐酸酸化对几种桡足类的急性毒性比较

    Institute of Scientific and Technical Information of China (English)

    张达娟; 李少菁; 王桂忠; 郭东晖

    2011-01-01

    The acute toxicity of ocean acidification induced by CO2 or HCl on several marine copepods was investigated by using the experimental ecological method. The results showed that, the 24 h and 48 h LC50 of copepods were pH 5. 85 to 6. 49 and pH 5. 93 to 6. 69 in the CO2-driven acidification groups,while were pH 5. 02 to 5. 69 and pH 5. 25 to 6. 12 in the HCl-driven groups. The split plot ANOVA indicated that the acute toxicity of CO2 -induced acidificarion on the copepods was significant higher than that of HCl-induced acidification. Furthermore , the sensitivity of copepods to scawater acidification was species-specific. The benthic copepod, Tigriopus japonicus , had higher tolerance to seawater acidification than the planktonic ones , and the herbivorous copepod, Calanus sinicus,had higher tolerance than the omnivorous and carnivorous copepods among the planktonic copepods. The obtained data also provide important reference for the further study on the impacts of ocean acidification on the physiological and biochemical of copepods.%利用实验生态学的方法研究了由二氧化碳和盐酸引起的海水酸化对几种桡足类的急性毒性,计算了24和48 hLC50(以pH值表示).结果表明:二氧化碳酸化条件下,几种桡足类的24和48 h LC50分别为pH 5.85~6.49和pH 5.93~6.69;盐酸酸化条件下,24和48 h LC50分别为pH 5.02~5.69和pH 5.25~6.12.裂区设计方差分析表明,二氧化碳酸化对桡足类的毒性显著高于盐酸酸化的毒性.此外,各种桡足类对海水酸化的耐受性具有高度的种类特异性:营底栖生活的日本虎斑猛水蚤的耐受性明显高于其他浮游性种类;在营浮游性生活的种类中,植食性种类(中华哲水蚤)对酸化的耐受性要高于杂食性和肉食性种类.本研究结果为进一步研究海水酸化对桡足类生理生化影响提供参考依据.

  18. 上海世博园后滩湿地桡足类群落特征及其对环境因子的响应%Response of Copepod Community Characteristics to Environmental Factors in the Backshore Wetland of Expo Garden,Shanghai

    Institute of Scientific and Technical Information of China (English)

    陈立婧; 吴艳芳; 景钰湘; 王聪; 张饮江

    2012-01-01

    The Backshore Wetland of Expo Garden was the emphasis of the World Expo construction project in Shanghai in 2010,China programming district.We carried out studies on the community structure and spatial-temporal variation of copepod from September 2009 to August 2010.Statistical Product and Service Solutions(SPSS) was used for relevant statistical analysis between physicochemical parameters and copepod standing crop.Canonical correspondence analysis(CCA) was applied to further explore the correlation between copepod species and environmental parameters using CANOCO 4.5.A total of 23 copepod species in 11 genera,6 families were identified.5 dominant species of copepod were recorded during the survey period.They were Eucyclops serrulatus,Thermocyclops taihokuensis,Mesocyclops leuckarti,Thermocyclops brevifurcatus and Microcyclops varicans.The annual mean density of copepod was(8.6±16.6) ind·L^-1 and the biomass was(0.083 6±0.143 1) mg·L^-1.The standing crop of copepod had its first peak in July,the second in October and the bottom in January.The highest trophic level was measured at Site 1,decreasing along the flowing direction of the water current,and the lowest level was found at Site 10.The Margelf index remained low in winter and spring,but was increased in summer and autumn.The community structure of copepod was analyzed in relation to water quality parameters by canonical correspondence analysis(CCA).Water temperature,pH,nitrate nitrogen,nitrite nitrogen,TN,TP and dissolved oxygen were strongly correlated with the copepod community structure.%上海世博园后滩湿地是中国2010年上海世界博览会规划区的重点项目.于2009年9月~2010年8月研究了桡足类群落结构的时空变化特征.运用SPSS 18.0软件进行相关统计分析,并利用CANOCO 4.5软件对桡足类数据和环境因子数据进行典范对应分析(CCA).全年共鉴定出桡足类23种,隶属于6科11属.优势种为锯缘真剑水蚤(Eucyclops serrulatus

  19. Selective grazing of Temora longicornis in different stages of a Phaeocystis globosa bloom - a mesocosm study

    DEFF Research Database (Denmark)

    Koski, Marja; Dutz, Jörg; Breteler, W.C.M.K.

    2005-01-01

    Selective grazing of a calanoid copepod Temora longicornis was measured during different stages of a Phaeocystis globosa bloom, in order to reveal (1) if T longicornis feeds on single cells and/or colonies of P. globosa in the presence of alternative food sources, (2) if copepod food selection...... of alternative food sources. In contrast, feeding on single cells was never significant, and the total contribution of P globosa to carbon ingestion of T longicornis was minor. T longicornis fed most actively on the decaying colonies, whereas during the peak of the bloom copepods selected against P globosa...... with highest proportional ingestion of heterotrophic organisms, but was not seriously reduced even during the peak of the bloom. We conclude that P globosa blooms should not threaten survival of copepod populations, but the population recruitment may depend on the type (and concentration) of the dominant...

  20. Assessing the identity and expression level of the cytochrome P450 20A1 (CYP20A1) gene in the BPA-, BDE-47, and WAF-exposed copepods Tigriopus japonicus and Paracyclopina nana.

    Science.gov (United States)

    Han, Jeonghoon; Kim, Duck-Hyun; Seo, Jung Soo; Kim, Il-Chan; Nelson, David R; Puthumana, Jayesh; Lee, Jae-Seong

    2017-03-01

    CYP20A1 is a member of the cytochrome P450 (CYP) superfamily, identified as an orphan P450 without any assigned biological function; hence, its continued status as an "orphan" gene. In order to address this shortcoming in our understanding of this superfamily, we sought to characterize the CYP20A1 gene in the copepods Tigriopus japonicus (Tj-CYP20A1) and Paracyclopina nana (Pn-CYP20A1) at their mRNA transcriptional level. We assessed the response of this gene's expression in various developmental stages and in response to treatment with bisphenol A (BPA), 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47), and water accommodated fractions (WAFs) of crude oil. As shown in the vertebrate CYP20A1, both Tj-CYP20A1 and Pn-CYP20A1 contained characteristic conserved motifs and domain regions (I helix, K helix and heme-binding motifs) with unusual amino acid sequences apparent in their gene structure. Also molecular characterization of the putative responsive elements in the promoter regions was performed. We observed transcriptional up-regulation of these genes during post-embryonic developmental stages including sex-specific up-regulation in adults. In addition, concentration- and time-dependent mRNA transcripts in response to xenobiotics (BPA, BDE-47, and WAFs) were seen. This study focuses on the molecular elucidation of CYP20A1 genes and their interactions with xenobiotics in the copepods T. japonicus and P. nana that provides important insight into the biological importance of CYP20A1 in invertebrates.

  1. The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective

    DEFF Research Database (Denmark)

    Bramm, Mette Elisabeth; Lassen, Majbritt Kjeldahl; Liboriussen, Lone;

    2009-01-01

    1. Variations in the light regime can affect the availability and quality of food for zooplankton grazers as well as their exposure to fish predation. In northern lakes light is particularly low in winter and, with increasing warming, the northern limit of some present-day plankton communities may...... in the life history of copepods. The strength of the fish effect on zooplankton biomass diminished with declining light and the effect of light was strongest in the presence of fish. 4. When fish were present, reduced light led to a shift from rotifers to calanoid copepods in the clear lake and from rotifers...

  2. Diet of Mysis diluviana reveals seasonal patterns of omnivory and consumption of invasive species in offshore Lake Michigan

    Science.gov (United States)

    O'Malley, Brian P.; Bunnell, David B.

    2014-01-01

    Recent changes in Lake Michigan’s lower trophic levels were hypothesized to have influenced the diet of omnivorous Mysis diluviana. In this study, the stomach contents of Mysis were examined from juvenile and adults collected monthly (April–October) from a 110-m bottom depth site to describe their seasonal diet in LakeMichigan during 2010. Diatoms were the most common prey item ingested, followed by calanoid copepods, and chrysophytes. Dreissenid veligers were documented in mysid diets for the first time in the Great Lakes, and Cercopagis pengoi were not only consumed but even preferred by adults in summer. Diet proportions by weight were dominated by calanoids, although diets showed a marked shift toward cladocerans in autumn. Juvenile and adult Mysis selected primarily for cladoceran prey but also selected for some calanoid copepod taxa. Comparing available Mysis diet data from 1985 to 2010 indicated generally fewer cladocerans and rotifers per gut and less consistent differences in copepods and Peridinium consumed. The seasonal composition of phyto- and zooplankton prey documented herein should be useful to those seeking to understand the trophic role of Mysis in offshore food webs, but caution should be expressed when generalizing similarities in Mysis diets across other lakes because Lake Michigan’s population seems relatively more herbivorous.

  3. Seasonal cycles of zooplankton from San Francisco Bay

    Science.gov (United States)

    Ambler, Julie W.; Cloern, James E.; Hutchinson, Anne

    1985-01-01

    The two estuarine systems composing San Francisco Bay have distinct zooplankton communities and seasonal population dynamics. In the South Bay, a shallow lagoon-type estuary, the copepods Acartia spp. and Oithona davisae dominate. As in estuaries along the northeast coast of the U.S., there is a seasonal succession involving the replacement of a cold-season Acartia species (A. clausi s.l.) by a warm-season species (A. californiensis), presumably resulting from the differential production and hatching of dormant eggs. Oithona davisae is most abundant during the fall. Copepods of northern San Francisco Bay, a partially-mixed estuary of the Sacramento-San Joaquin Rivers, organize into discrete populations according to salinity distribution: Sinocalanus doerrii (a recently introduced species) at the riverine boundary, Eurytemora affinis in the oligohaline mixing zone, Acartia spp. in polyhaline waters (18–30\\%), and neritic species (e.g., Paracalanus parvus) at the seaward boundary. Sinocalanus doerrii and E. affinis are present year-round. Acartia clausi s.l.is present almost year-round in the northern reach, and A. californiensis occurs only briefly there in summer-fall. The difference in succession of Acartia species between the two regions of San Francisco Bay may reflect differences in the seasonal temperature cycle (the South Bay warms earlier), and the perennial transport of A. clausi s.l. into the northern reach from the seaward boundary by nontidal advection.

  4. Recruitment from an egg bank into the plankton in Baisha Bay, a mariculture base in Southern China

    Science.gov (United States)

    Wang, Qing; Luan, Lei-Lei; Chen, Liang-Dong; Yuan, Dan-Ni; Liu, Sheng; Hwang, Jiang-Shiou; Yang, Yu-Feng

    2016-11-01

    The potential recruitment of resting eggs of calanoid copepods and rotifers to planktonic populations was investigated in the surface and sub-surface sediments of three mariculture zones: an integrated seaweed Gracilaria lemaneiformis and shellfish cultivation area (G), a fish cultivation area (F), and a shellfish cultivation area (S), as well as the sediments of a nearby control sea area (C) in a mariculture base in Southern China. The potential recruitment of copepod and rotifer eggs in the sediments of C and G was significantly higher than in F and S. Potential recruitment in the sub-surface sediments of F and S was not observed, suggesting that fish and shellfish mariculture may be responsible for this decrease. The hatching success of resting eggs of copepods and rotifers was affected by mariculture type, and that large-scale seaweed cultivation may offset the adverse effect of fish and shellfish cultivation on the resting eggs if integrated cultivation is adopted.

  5. Parasitic copepods in the nasal fossae of five fish species (Characiformes from the upper Paraná river floodplain, Paraná, Brazil = Copépodes parasitos de fossas nasais de cinco espécies de peixes (Characiformes da planície de inundação do alto rio Paraná, Paraná, Brasil

    Directory of Open Access Journals (Sweden)

    Ana Carolina Figueiredo Lacerda

    2007-10-01

    Full Text Available The present work had the objective to study parasitic copepods in thenasal fossae of fish from the upper Paraná river floodplain. Fish were captured in different locations of the floodplain in March, June and September, 2004. A total of 73 specimens (Characiformes were collected, belonging to 4 distinct families and 5 species: Acestrorhynchus lacustris (Acestrorhynchidae, Schizodon borellii (Anostomidae, Prochilodus lineatus (Prochilodontidae, Serrasalmus marginatus and Serrasalmus maculatus (Serrasalmidae. Among 73 fishes examined, 53 were parasitized by nasal fossae copepods, varying from 1 to 146 parasites per host. Parasites found belonged to 3 known species: Gamidactylus jaraquensis Thatcher & Boeger, 1984; Gamispatulus schizodontis Thatcher & Boeger, 1984; and Rhinergasilus piranhus Boeger & Thatcher, 1988. There were differences in parasite corporal measurements and in the quantity of parasites per host in relation to copepod parasites from the Amazon region. The present study constitutes one of the few studies of identification of copepod parasites in the nasal fossae of fish from the Southern region of Brazil.O presente trabalho teve como objetivo o estudo de copépodes parasitos de fossas nasais de peixes da planície de inundação do alto Rio Paraná. As coletas foram realizadas em diversos pontos da planície nos meses de março, junho e setembro de 2004. Foram coletados 73 exemplares de peixes da ordem Characiformes, de quatrofamílias distintas, pertencentes a cinco espécies: Acestrorhynchus lacustris, Prochilodus lineatus, Schizodon borellii, Serrasalmus maculatus e Serrasalmus marginatus. Dentre os 73 peixes examinados, 53 encontravam-se parasitados por copépodes de fossas nasais,variando de 1 a 146 parasitos por peixe. Os parasitos encontrados pertenciam a três espécies conhecidas: Gamidactylus jaraquensis Thatcher & Boeger, 1984; Gamispatulus schizodontis Thatcher & Boeger, 1984 e Rhinergasilus piranhus Boeger & Thatcher

  6. Dose- and time-dependent expression of aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (ARNT) in PCB-, B[a]P-, and TBT-exposed intertidal copepod Tigriopus japonicus.

    Science.gov (United States)

    Kim, Bo-Mi; Rhee, Jae-Sung; Hwang, Un-Ki; Seo, Jung Soo; Shin, Kyung-Hoon; Lee, Jae-Seong

    2015-02-01

    The aryl hydrocarbon receptor (AhR) and aryl hydrocarbon nuclear translocator (ARNT) genes from the copepod Tigriopus japonicus (Tj) were cloned to examine their potential functions in the invertebrate putative AhR-CYP signaling pathway. The amino acid sequences encoded by the Tj-AhR and Tj-ARNT genes showed high similarity to homologs of Daphnia and Drosophila, ranging from 68% and 70% similarity for the AhR genes to 56% for the ARNT genes. To determine whether Tj-AhR and Tj-ARNT are modulated by environmental pollutants, transcriptional expression of Tj-AhR and Tj-ARNT was analyzed in response to exposure to five concentrations of polychlorinated biphenyl (PCB 126) (control, 10, 50, 100, 500 μg L(-1)), benzo[a]pyrene (B[a]P) (control, 5, 10, 50, 100 μg L(-1)), and tributyltin (TBT) (control, 1, 5, 10, 20 μg L(-1)) 24h after exposure. A time-course experiment (0, 3, 6, 12, 24h) was performed to analyze mRNA expression patterns after exposure to PCB, B[a]P, and TBT. T. japonicus exhibited dose-dependent and time-dependent upregulation of Tj-AhR and Tj-ARNT in response to pollutant exposure, and the degree of expression was dependent on the pollutant, suggesting that pollutants such as PCB, B[a]P, and TBT modulate expression of Tj-AhR and Tj-ARNT genes in the putative AhR-CYP signaling pathway.

  7. Capture efficiency for small dominant mesozooplankters (Copepoda, Appendicularia off Buenos Aires Province (34ºS-41ºS, Argentine Sea, using two plankton mesh sizes

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    Rosana Di Mauro

    2009-09-01

    Full Text Available Two plankton mesh sizes of 67 µm and 220 µm were compared to evaluate their efficiency in the capture of the smallest copepods and appendicularians present in the Buenos Aires coastal area (Argentine Sea. A total of 12 copepod species and one appendicularian species were recorded in this study. The copepods were separated into 4 groups: harpacticoids, cyclopoids, small calanoids and large calanoids and their developmental stages. Among the cyclopoids, Oithona nana was the most abundant species, being 96.29 % underestimated by the 220 µm mesh, whereas Microsetella norvegica dominated the harpacticoids and was captured exclusively by the smaller mesh. Similar results were found for copepodites I-III of small calanoids, whose net sampled underestimation reached 99.70%. On the other hand, no significant difference between meshes was found for adults and copepodites IV-V of small calanoids or any of the developmental stages of large calanoids. A great loss of biomass was observed for O. nana when applying the larger mesh. In regards to the appendicularian Oikopleura dioica, all size ranges below 1,000 µm length were better estimated by the 67 µm mesh in terms of abundance and biomass. Our results clearly show that the 67 µm mesh was more efficient in the capture of early stages of small copepods thus providing a more accurate estimation of the fish larvae prey field.Compararam-se os copépodos e apendiculárias coletados, na zona costeira do Estado de Buenos Aires (Argentina, com duas redes de plâncton, tipo mini-bongo, de abertura de malha de 67 µm e 220 µm. Registraram-se 12 espécies de copépodos e uma de apendiculária. Os copépodos foram separados de acordo com as categorias: harpaticoides, ciclopoides, e calanoides pequenos e grandes. O cálculo da abundância de Oithona nana, que foi a espécie mais abundante no material analizado, demonstrou que a coleta com rede de 220 µm teve uma subestimativa de 92,29%, em relação à coleta

  8. Eco-friendly drugs from the marine environment: spongeweed-synthesized silver nanoparticles are highly effective on Plasmodium falciparum and its vector Anopheles stephensi, with little non-target effects on predatory copepods.

    Science.gov (United States)

    Murugan, Kadarkarai; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Madhiyazhagan, Pari; Hwang, Jiang-Shiou; Wang, Lan; Dinesh, Devakumar; Suresh, Udaiyan; Roni, Mathath; Higuchi, Akon; Nicoletti, Marcello; Benelli, Giovanni

    2016-08-01

    Mosquitoes act as vectors of devastating pathogens and parasites, representing a key threat for millions of humans and animals worldwide. The control of mosquito-borne diseases is facing a number of crucial challenges, including the emergence of artemisinin and chloroquine resistance in Plasmodium parasites, as well as the presence of mosquito vectors resistant to synthetic and microbial pesticides. Therefore, eco-friendly tools are urgently required. Here, a synergic approach relying to nanotechnologies and biological control strategies is proposed. The marine environment is an outstanding reservoir of bioactive natural products, which have many applications against pests, parasites, and pathogens. We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles (AgNP) using the spongeweed Codium tomentosum, acting as a reducing and capping agent. AgNP were characterized by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In mosquitocidal assays, the 50 % lethal concentration (LC50) of C. tomentosum extract against Anopheles stephensi ranged from 255.1 (larva I) to 487.1 ppm (pupa). LC50 of C. tomentosum-synthesized AgNP ranged from 18.1 (larva I) to 40.7 ppm (pupa). In laboratory, the predation efficiency of Mesocyclops aspericornis copepods against A. stephensi larvae was 81, 65, 17, and 9 % (I, II, III, and IV instar, respectively). In AgNP contaminated environment, predation was not affected; 83, 66, 19, and 11 % (I, II, III, and IV). The anti-plasmodial activity of C. tomentosum extract and spongeweed-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. Fifty percent inhibitory concentration (IC50) of C. tomentosum were 51.34 μg/ml (CQ-s) and 65.17 μg/ml (CQ-r); C. tomentosum-synthesized AgNP achieved IC50 of 72.45 μg/ml (CQ-s) and 76.08

  9. Mesozooplankton grazing on picocyanobacteria in the Baltic Sea as inferred from molecular diet analysis.

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    Nisha H Motwani

    Full Text Available Our current knowledge on the microbial component of zooplankton diet is limited, and it is generally assumed that bacteria-sized prey is not directly consumed by most mesozooplankton grazers in the marine food webs. We questioned this assumption and conducted field and laboratory studies to examine picocyanobacteria contribution to the diets of Baltic Sea zooplankton, including copepods. First, qPCR targeting ITS-1 rDNA sequence of the picocyanobacteria Synechococcus spp. was used to examine picocyanobacterial DNA occurrence in the guts of Baltic zooplankton (copepods, cladocerans and rotifers. All field-collected zooplankton were found to consume picocyanobacteria in substantial quantities. In terms of Synechococcus quantity, the individual gut content was highest in cladocerans, whereas biomass-specific gut content was highest in rotifers and copepod nauplii. Moreover, the gut content in copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton abundance in the water column at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on picoplankton when food in the preferred size range declines. Second, a feeding experiments with a laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and microalga Rhodomonas salina confirmed that copepods ingested Synechococcus, even when the alternative food was plentiful. Finally, palatability of the picocyanobacteria for A. tonsa was demonstrated using uptake of (13C by the copepods as a proxy for carbon uptake in feeding experiment with (13C-labeled S. bacillaris. These findings suggest that, if abundant, picoplankton may become an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments.

  10. Virus-phytoplankton adhesion: a new WSSV transmission route to zooplankton

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pathogenicity of white spot syndrome virus (WSSV) to zooplankton species, rotifer Brachionus urceus (Linnaeus), copepod Acartia clausi (Giesbrecht) and mysid shrimp Neomysis awatschensis (Brandt), was estimated by immersion challenge and virus-phytoplankton adhesion route to investigate a potential new transmission route of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus-phytoplankton adhesion route, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus-phytoplankton adhesion route is a successful new transmission route of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

  11. Decadal changes in zooplankton abundance and phenology of Long Island Sound reflect interacting changes in temperature and community composition.

    Science.gov (United States)

    Rice, Edward; Stewart, Gillian

    2016-09-01

    Between 1939 and 1982, several surveys indicated that zooplankton in Long Island Sound, NY (LIS) appeared to follow an annual cycle typical of the Mid-Atlantic coast of North America. Abundance peaked in both early spring and late summer and the peaks were similar in magnitude. In recent decades, this cycle appeared to have shifted. Only one large peak tended to occur, and summer copepod abundance was consistently reduced by ∼60% from 1939 to 1982 levels. In other Mid-Atlantic coastal systems such a dramatic shift has been attributed to the earlier appearance of ctenophores, particularly Mnemiopsis leidyi, during warmer spring months. However, over a decade of surveys in LIS have consistently found near-zero values in M. leidyi biomass during spring months. Our multiple linear regression model indicates that summer M. leidyi biomass during this decade explains variation in summer copepod abundance. During these recent, warmer years, summer copepod community shifts appear to explain the loss of copepod abundance. Although Acartia tonsa in 2010-2011 appeared to be present all year long, it was no longer the dominant summer zooplankton species. Warmer summers have been associated with an increase in cyanobacteria and flagellates, which are not consumed efficiently by A. tonsa. This suggests that in warming coastal systems multiple environmental and biological factors interact and likely underlie dramatic alterations to copepod phenology, not single causes.

  12. Bioluminescence in Dinoflagellates: Evidence that the Adaptive Value of Bioluminescence in Dinoflagellates is Concentration Dependent.

    Science.gov (United States)

    Hanley, Karen A; Widder, Edith A

    2017-03-01

    Three major hypotheses have been proposed to explain why dinoflagellate bioluminescence deters copepod grazing: startle response, aposematic warning, and burglar alarm. These hypotheses propose dinoflagellate bioluminescence (A) startles predatory copepods, (B) warns potential predators of toxicity, and (C) draws the attention of higher order visual predators to the copepod's location. While the burglar alarm is the most commonly accepted hypothesis, it requires a high concentration of bioluminescent dinoflagellates to be effective, meaning the bioluminescence selective advantage at lower, more commonly observed, dinoflagellate concentrations may result from another function (e.g. startle response or aposematic warning). Therefore, a series of experiments was conducted to evaluate copepod grazing (Acartia tonsa) on bioluminescent dinoflagellates (during bioluminescent and nonbioluminescent phases, corresponding to night and day, respectively) at different concentrations (10, 1000, and 3000 cells mL(-1) ), on toxic (Pyrodinium bahamense var. bahamense) and nontoxic (Lingulodinium polyedrum) bioluminescent dinoflagellates, and in the presence of nonluminescent diatoms (Thalassiosira eccentrica). Changes in copepod ingestion rates, clearance rates, and feeding preferences as a result of these experimental factors, particularly during the mixed trails with nonluminescent diatoms, indicate there is a concentration threshold at which the burglar alarm becomes effective and below which dinoflagellate bioluminescence functions as an aposematic warning.

  13. Myzomolgus sipunculensis sp. nov. (Cyclopoida, Catiniidae, a new copepod associated with sipunculan worms from Brazil Myzomolgus sipunculensis sp. nov. (Cyclopoida, Catiniidae, um novo copépode associado a sipuncúlidos do Brasil

    Directory of Open Access Journals (Sweden)

    Terue C. Kihara

    2007-01-01

    Full Text Available Catiniid copepods are characterized by the presence of a pedunculate sucker on the antenna. Four genera are currently included in the family Catiniidae: Catinia, Cotylemyzon, Cotylomolgus and Myzomolgus, the most speciose. Within the framework of the Special Research Program "Conservation and Sustainable Use of the Biodiversity of the State of São Paulo - Biota/FAPESP", a new species of Myzomolgus was found as an external associate of Sipunculus nudus and S. phalloides phalloides. The sipunculan worms were collected during the low tide in Araçá Beach, State of São Paulo, Brazil (23º49’02"S, 45º24’19"W. The new species differs from its three congeners, namely M. stupendus from France and M. tenuis and M. orientalis from Korea, by the peculiar ornamentation of the third antennal segment, morphology of mandible and leg 6 and presence of denticulate area between maxillipeds. The description of this new species raises to four the number of catiniid species (one of Catinia and two of Myzomolgus associated with the widely distributed S. nudus. In Brazil, this is the first record of Myzomolgus and the second species associated with sipunculan worms (a new species of Catinia found on S. phalloides phalloides is under description.Os copépodes catiniídeos se caracterizam pela presença de uma ventosa pedunculada na antena. Atualmente, quatro gêneros estão incluídos na família Catiniidae: Catinia, Cotylemyzon, Cotylemolgus e Myzomolgus, o mais especioso. Como parte de um programa especial de pesquisa "Conservação e Uso Sustentável da Biodiversidade do Estado de São Paulo - Biota/FAPESP", uma nova espécie de Myzomolgus foi encontrada associada à superfície externa de Sipunculus nudus e S. phalloides phalloides. Os sipuncúlidos foram coletados na Praia do Araçá, Estado de São Paulo, Brasil (23º49’02"S, 45º24’19"W, durante a maré baixa. A nova espécie difere de M. stupendus, da França, e M. tenuis e M. orientalis, ambos da

  14. Copepods link quahog growth to climate

    NARCIS (Netherlands)

    Witbaard, R.; Jansma, E.; Sass, U.G.W.

    2003-01-01

    From samples collected in 1983, 1991 and 2000, a long-term growth record for the bivalve Arctica islandica from the northern North Sea was constructed with methods derived from dendrochronology. Subsequent response-function analyses demonstrated that shell growth was mainly influenced by the abundan

  15. Cladocers, Copepods and Rotifers in rice-fish culture handled with metsulfuron-methyl and azimsulfuron herbicides and carbofuran insecticide Cladocera, Copepoda e Rotifera em rizipiscicultura tratada com os herbicidas metsulfuron-metílico e azimsulfuron e o inseticida carbofuran

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    Jaqueline Ineu Golombieski

    2008-11-01

    Full Text Available This study determined the effects of metsulfuron-methyl, azimsulfuron and carbofuran in communities: Cladocers, Copepods and Rotifers that are present in irrigated rice farming with the rice-fish system. The field experiment was conducted in the 2004/05 growing season with eight treatments. The fish species were: Cyprinus carpio, Ctenopharyngodon idella and Aristichthys nobilis, introduced seven days after treatments were applied. Water samples were collected 17 days before and 1st, 3rd, 10th, 18th, 31th, 51th, and 75th days after the agrochemicals were applied for identification and evaluation of the zooplankton. The results indicated that the herbicides did not affect the zooplankton community studied and carbofuran insecticide application provoked negative effects in Cladocers. Copepods and Rotifers were slightly affected by carbofuran.O presente estudo determinou o efeito de metsulfuron-metílico, azimsulfuron e carbofuran nas comunidades: Cladocera, Copepoda e Rotifera presentes em lavouras de arroz irrigado com o sistema de rizipiscicultura. O experimento foi conduzido durante a safra agrícola 2004/05 com oito tratamentos. As espécies de peixes utilizadas foram: Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, introduzidas sete dias após a aplicação dos tratamentos. Amostras de água foram coletadas 17 dias antes e no(s 1°, 3°, 10°, 18°, 31°, 51° e 75° dias após a aplicação dos tratamentos para a identificação e a avaliação de zooplâncton. Os resultados indicam que os herbicidas estudados não afetaram a comunidade zooplanctônica e a aplicação do inseticida carbofuran provocou efeitos negativos em Cladocera. Copepoda e Rotifera foram pouco afetados pelo carbofuran.

  16. 微颗粒饲料与冷藏桡足类对大黄鱼稚鱼消化酶活力、肠和肝脏显微结构的影响%EVALUATION OF MICRODIETS AND FROZEN COPEPODS ON DIGESTIVE ENZYME ACTIVITIES, INTESTINAL AND LIVER MICROSTRUCTURES OF LARGE YELLOW CROAKER (PSEUDOSCIAENA CROCEA R.) LARVAE

    Institute of Scientific and Technical Information of China (English)

    于海瑞; 艾庆辉; 麦康森; 马洪明; José Luis Zambonino-Infante; Chantal Louise Cahu

    2012-01-01

    A feeding trial was conducted to evaluate effects of three newly developed microdiets (MDs: Diet 1-Diet 3), a mixed diet (Diet 4: Diet 3 combined with frozen copepods) and frozen copepods (Diet 5, control) on digestive enzymatic activities, intestine and liver microstructures of large yellow croaker (Pseudosciaena crocea R.) larvae, which had an initial mean body weight of (13.80 ?0.40) mg from 25 to 60 days after hatching (DAH). The results showed that trypsin activities exhibited no significant difference between fish fed with the MDs at 35 and 60 DAH, although those at 25 DAH showed lower trypsin activities, and there was no significant difference between fish fed with mixed diet and frozen copepods. No significant differences were observed between fish fed with the experimental diets except frozen copepods, the latter led to higher amylase activity at 35 DAH than at 25 and 60 DAH. As fish grew older, aminopepti-dase N and alkaline phosphatase activities increased in fish fed with the experimental diets except for Diet 4 and Diet 5. No lipid droplets were observed in anterior-mediate intestinal mucosa in 35-day-old fish that were fed with the experimental diets with the exception of the Diet 4. Fish fed with the MDs presented deeper intestinal mucosa folds and su-pranuclear vacuoles in the rectum, while rectal folds from fish fed with the frozen copepods were nearly flat and lacked supranuclear vacuoles. Fish fed with the MDs displayed numerous lipid vacuoles in hepatocytes with nuclear migration. Liver from fish fed with the mixed diet had numerous lipid vacuoles in hepatocytes with nuclear migration at 35 DAH but such vacuoles decreased at 60 DAH. Liver from fish fed with the frozen copepods resulted in some intercellular spaces, collapsed cytoplasm and pycnotic nuclei of hepatocytes that were similar to starvation condition. These results indicated that suitable MDs could improve the development of digestive system of large yellow croaker larvae. Diet 1 can

  17. 内陆排污对杭州湾南岸滩涂湿地浮游桡足类群落结构的影响%Influence of pollutants drained 0020z from land on copepods community structure in mudflats of Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    李共国; 屠霄霞; 廖何朝兴; 王佩儿; 王自磐; 杨季芳

    2012-01-01

    In order to understand the spatial-temporal variation of copepod species composition, abundance and biodiversity, 40 surveys were conducted at high tide level and middle tide level in the mudflat wetlands of the Hangzhou Bay. The samples were collected at 5 profiles (S1 to S5) in Apr. (spring) , Jun. (summer) , Oct. (autumn) 2010 and Jan. (winter) 2011. A total of 19 species belonging to 3 orders (7 Cyclopoida, 5 Calanoida and 7 Harpacticoida) , of which 8 species were freshwater ecological type, 11 species were brackish-water type, were identified. According to the annual average abundance and Occurrence frequency of various cope-pod species, the dominant ones were Sinocalanus dorrii, Tachidius triangularis and Thermocyclops taihokuensis, all belonging to the freshwater ecological type. The community abundance of copepods ranged between 2. 64 ~ 39. 16 /L with an average of 13. 54 /L. Copepod biomass ranged between 0 ~2.078 mg/L with an average of 0. 164 mg/L. Calanoida abundance and biomass accounted alone for 29. 32% and 79. 88% of the total copepods, respectively. The seasonal differences in abundance and biomass are as follows: spring > autumn > summer > winter. Over a one year period abundance and biomass were distributed such that S3 > S2 > S1 > S5 > S4. The middle tide level exceeded 67. 00% in abundance compared to the figures for the high tide level in profiles S2. The value of Margalef's richness index ( d) was between 1.20 ~ 6. 20, averaged 3. 35. Influence of pollution water drained from land away on copepods community was more serious in middle tide level than that in high tide level.%2010年1月~ 2011年1月,在杭州湾南岸滩涂湿地5个断面(S1~S3为排水区,S4~S5为非排水区.)10个采样站进行桡足类群落结构的周年调查,分析了不同生态环境下桡足类群落的种类组成、密度、生物量和种类丰富度等时空变化特征.共发现桡足类19种,剑水蚤和猛水蚤各7种、哲水蚤5种,其中,8

  18. Unexpected Regularity in Swimming Behavior of Clausocalanus furcatus Revealed by a Telecentric 3D Computer Vision System.

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    Giuseppe Bianco

    Full Text Available Planktonic copepods display a large repertoire of motion behaviors in a three-dimensional environment. Two-dimensional video observations demonstrated that the small copepod Clausocalanus furcatus, one the most widely distributed calanoids at low to medium latitudes, presented a unique swimming behavior that was continuous and fast and followed notably convoluted trajectories. Furthermore, previous observations indicated that the motion of C. furcatus resembled a random process. We characterized the swimming behavior of this species in three-dimensional space using a video system equipped with telecentric lenses, which allow tracking of zooplankton without the distortion errors inherent in common lenses. Our observations revealed unexpected regularities in the behavior of C. furcatus that appear primarily in the horizontal plane and could not have been identified in previous observations based on lateral views. Our results indicate that the swimming behavior of C. furcatus is based on a limited repertoire of basic kinematic modules but exhibits greater plasticity than previously thought.

  19. Estudio anual del zooplancton: composición, abundancia, biomasa e hidrología del norte de Quintana Roo, mar Caribe de México Annual study of zooplankton: composition, abundance, biomass and hydrology from the north of Quintana Roo, Mexican Caribbean Sea

    Directory of Open Access Journals (Sweden)

    José N Álvarez-Cadena

    2007-12-01

    Full Text Available Se llevaron a cabo muestreos de zooplancton en la zona lagunar y costera del Caribe mexicano, desde Puerto Morelos hasta Cancún. Las recolectas se llevaron a cabo de enero a diciembre de 2004 en 12 localidades. Se identificaron 41 grupos del zooplancton donde los copépodos fueron los más abundantes (61% seguidos de las larvas de equinodermos (17% y decápodos (5%. El copépodo Acartia tonsa fue la especie más abundante de este grupo en el Sistema Lagunar Nichupté (SLN. En la zona marina adyacente los copépodos estuvieron representados en orden de importancia por Acartia spinata, Pseudocalanus sp. y Calanopia americana. En todas las estaciones se capturaron equinodermos del tipo equinopluteus-ofiopluteus, pero con mayor abundancia en el SLN. El quetognato Ferosagitta hispida fue la única especie que se encontró en el SLN, donde fue más abundante. Los decápodos estuvieron representados principalmente por larvas zoeas; las larvas de peces por 54 familias, de las cuales los góbidos de los géneros Ctenogobius sp., Gobionellus sp. y Gobiosoma sp. fueron los mejor representados, particularmente para el SLN. La biomasa fue mayor en el SLN.Zooplankton sampling was carried out in the northern coast of the Mexican Caribbean Sea, from Puerto Morelos to Cancun. Captures were made with a conic net 0.4m diameter, 1.40m length and 0.330 mm mesh from January to December 2004 at twelve locations. A total of 41 zooplankton groups were identified. Copepods were the most abundant taxa making up 61%, followed by echinoderms (17% and decapods (5%. Acartia tonsa at the Nichupte Lagoon System (SLN over numbered the copepod fauna and occasionally the whole zooplankton population. Along the coast Acartia spinata, Pseudocalanus sp, and Calanopia americana were the most important copepods. Echinoderms larvae such as echinopluteus-ophiopluteus were present at all sampled stations but were more abundant at the NLS. For chaetognaths, Ferosagitta hispida dominated

  20. Study on the biological oceanographic characteristics of planktonic copepods in the waters north of Taiwan Province Ⅲ. Indicator species%台湾以北海域浮游桡足类生物海洋学特征的研究Ⅲ.指示性种类

    Institute of Scientific and Technical Information of China (English)

    杨关铭; 何德华; 王春生; 苗育田; 于洪华

    2000-01-01

    在对台湾以北海域浮游桡足类生物海洋学特征研究Ⅱ.群落特征研究的基础上,用不同生态类群的指示性种类分布来分析对应水系的变化过程.结果表明,普通波水蚤(Undinula vulgaris)和帽状真哲水蚤(Eucalanus pileatus)的数量分布可以指示台湾海峡水的季节变化和消长趋势;海洋真刺水蚤(Euchaeta marina)能反映黑潮表层水的影响程度;热带大洋高盐偏低温类群种类在陆架区的分布状况可反映黑潮次表层水的入侵涌升范围;中华哲水蚤(Calanus sinicus)的分布反映了沿岸水势力影响的季节差异,可能是受陆架区横向环流的影响,它能扩布到较远岸区域,此时该种类对偏低温的适宜性致使其在较低温水体中的丰度较高;对热带大洋低温高盐类群种类的研究发现,春季隆线似哲水蚤(Calanoides carinatus)在测区陆架区广泛分布是由冬季在台湾浅滩南部上升流区该种的大量涌现并随台湾海峡水北上携带而来的,然而,从隆线似哲水蚤和该类群另两种在陆坡下层的出现显示了中、深层水有可能在本区东南侧涌升.

  1. The Afro-Asian cyclopoid Mesocyclops aspericornis (Crustacea: Copepoda in eastern Mexico with comments on the distribution of exotic copepods El cyclopoide afro-asiático Mesocyclops aspericornis (Crustacea: Copepoda en el este de México con comentarios sobre la distribución de copépodos exóticos

    Directory of Open Access Journals (Sweden)

    Eduardo Suárez-Morales

    2011-03-01

    Full Text Available The Afro-Asian freshwater copepod Mesocyclops aspericornis (Daday, 1906, deemed as an exotic species in the Americas, is known to occur disjunctly in Mexico, South America, and the insular Caribbean. Adult females of this species were recorded.from samples collected in the state of Veracruz, on the Atlantic coast of Mexico.The morphology of these specimens is identical in most characters to those described or depicted in previous taxonomic accounts. The 3 known Mexican populations belong to the "western" group of M. aspericornis. The subtle morphological variations among the Mexican populations and their isolation suggest that each could be the result of independent events of dispersion or introduction via aquaculture. This is the third confirmed report of M. aspericornis in Mexico, but the first one in the Atlantic side of Middle America. The states of Tabasco and Chiapas harbour 3 of the 4 species of exotic freshwater copepods known to occur in Mexico.El copépodo dulceacuícola afro-asiático Mesocyclops aspericornis (Daday, 1906, considerado como especie exótica en América, se sabía presente de modo disperso en México, Sudamérica y en las islas del Caribe. A partir de muestras recolectadas en el estado de Veracruz, en la costa del Atlántico de México, se registraron hembras adultas de esta especie. La morfología de estos ejemplares es idéntica en la mayoría de los caracteres a la descrita o ilustrada en trabajos taxonómicos previos. Las 3 poblaciones conocidas en México pertenecen al grupo "occidental" de M. aspericornis. Las sutiles variaciones morfológicas entre las poblaciones mexicanas y su aislamiento sugieren que cada una podría ser resultado de eventos independientes por dispersión o introducción vía la acuacultura. Este es el tercer registro confirmado de M. aspericornis en México, pero el primero en Mesoamérica en el lado del Atlántico. Los estados de Tabasco y Chiapas alojan 3 de las 4 especies de copépodos ex

  2. Trophic ecology of bottom fishes assemblage along coastal areas of Thailand

    Science.gov (United States)

    Hajisamae, Sukree

    2009-04-01

    Food preferences, feeding attributes, trophic guilds, and ontogenetic changes in diet compositions of 45 fish species collected along coastal waters in the southern areas of the South China Sea, Thailand were examined. Most species had high food intake and fed on specific ranges of food types. Shrimp was the most important food (31.7%), followed by calanoid copepod (16.8%), fish (12.7%) and gammarid amphipod (8.3%). These fishes can be categorized into six different trophic guilds and further divided into four categories namely; piscivore, zooplanktivore, zoobenthivore and miscellaneous/opportunist. Numbers of feeding guilds at each depth vary between four and five. Four of these are consistently found throughout the year at all zones; shrimp predator, piscivore, calanoid copepod feeder and a combination of polychaete and other food feeders. Ontogenetic studies indicate that fishes are more likely to group according to species rather than size. This scientific information is important when examining the complex association between fishes and identifying groups of species using similar resources.

  3. Lake Ontario zooplankton in 2003 and 2008: community changes and vertical redistribution

    Science.gov (United States)

    Rudstam, Lars G.; Holeck, Kristen T.; Bowen, Kelly L.; Watkins, James M.; Weidel, Brian C.; Luckey, Frederick J.

    2014-01-01

    Lake-wide zooplankton surveys are critical for documenting and understanding food web responses to ecosystem change. Surveys in 2003 and 2008 during the binational intensive field year in Lake Ontario found that offshore epilimnetic crustacean zooplankton declined by a factor of 12 (density) and factor of 5 (biomass) in the summer with smaller declines in the fall. These declines coincided with an increase in abundance of Bythotrephes and are likely the result of direct predation by, or behavioral responses to this invasive invertebrate predator. Whole water column zooplankton density also declined from 2003 to 2008 in the summer and fall (factor of 4), but biomass only declined in the fall (factor of 2). The decline in biomass was less than the decline in density because the average size of individual zooplankton increased. This was due to changes in the zooplankton community composition from a cyclopoid/bosminid dominated community in 2003 to a calanoid dominated community in 2008. The increase in calanoid copepods was primarily due to the larger species Limnocalanus macrurus and Leptodiaptomus sicilis. These coldwater species were found in and below the thermocline associated with a deep chlorophyll layer. In 2008, most of the zooplankton biomass resided in or below the thermocline during the day. Increased importance of copepods in deeper, colder water may favor cisco and rainbow smelt over alewife because these species are better adapted to cold temperatures than Alewife.

  4. Diet shifts by planktivorous and benthivorous fishes in northern Lake Michigan in response to ecosystem changes

    Science.gov (United States)

    Bunnell, David B.; Davis, Bruce M.; Chriscinske, Margret Ann; Keeler, Kevin M.; Mychek-Londer, Justin G.

    2015-01-01

    In Lake Michigan, diets of planktivorous and benthivorous fishes have varied over the past decades, in part owing to food web changes. To update diet information and compare them to a similar effort in 1994–1995, we analyzed the diets of seven benthivorous and planktivorous fish species collected along two northern Lake Michigan transects that spanned nearshore (18 m), intermediate (46 m), and offshore (91, 110, 128 m) bottom depths during spring, summer, and autumn of 2010. Calanoid copepods (e.g., Limnocalanus macrurus, Leptodiaptomus sicilis, and Senecella calanoides) comprised a majority of the diets in at least one season for all sizes of alewife (Alosa pseudoharengus), bloater (Coregonus hoyi), and rainbow smelt (Osmerus mordax). Similarly, Mysis diluviana was the highest proportion in at least one season for large sizes of alewife, bloater, and rainbow smelt, as well as slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii). The diets of the remaining two species, ninespine stickleback (Pungitius pungitius) and round goby (Neogobius melanostomus), were dominated by herbivorous cladocerans or dreissenid mussels, respectively. Interspecific diet overlap was minimal at 18 and 46 m. In offshore waters, however, overlap was relatively high, driven by frequent consumption of Mysis. Relative to 1994–1995, 2010 diets revealed increased feeding on calanoid copepods and Mysis, with corresponding declining consumption of Diporeia spp. and herbivorous cladocerans. Relative diet weight was also higher in 1994–1995 than in 2010 for small and large bloater and both sculpin species. We hypothesize that the shifts in diets are reflective of community-level changes in invertebrate prey availability.

  5. Persistência na água e influência de herbicidas utilizados na lavoura arrozeira sobre a comunidade zooplanctônica de Cladocera, Copepoda e Rotifera Water persistence and influence of herbicides utilized in rice paddy about zooplankton community of Cladocers Copepods and Rotifers

    Directory of Open Access Journals (Sweden)

    Geovane Boschmann Reimche

    2008-02-01

    Full Text Available Em lavoura de arroz irrigado, é utilizada uma grande quantidade de agroquímicos que, dependendo da sua persistência a campo e toxicidade, podem contaminar corpos d’água e afetar organismos vivos. Com o objetivo de determinar o efeito de concentrações de campo dos herbicidas Clomazone, Quinclorac, Metsulfuron-methyl e Propanil na comunidade zooplanctônica (Cladocera, Copepoda e Rotifera, conduziu-se um experimento em viveiros de aqüicultura, de março a maio de 2005, na estação do outono. Nos dias 1°, 2°, 3°, 7°, 10°, 18°, 31° e 51° após a aplicação dos herbicidas, foram coletadas amostras de água para se determinarem parâmetros físico-químicos da água, concentração dos herbicidas e comunidade zooplanctônica. Os parâmetros médios da qualidade da água foram: oxigênio dissolvido (3,5mg L-1, temperatura (20,1°C, pH (6,0, dureza total (18mg L-1 de CaCO3 e alcalinidade total (9mg L-1 de CaCO3. A ordem decrescente de persistência dos herbicidas na água foi Clomazone = Quinclorac > Propanil > Metsulfuron-methyl, com média de 31, 31, 10 e 7 dias, respectivamente. Os resultados indicaram que os herbicidas provocaram poucas alterações na densidade de organismos dos grupos Rotifera e Copepoda (Adulto e Nauplio. A densidade do grupo Cladocera permaneceu baixa para todo o período experimental.In the rice paddy field it is used a large amount of agrochemical that, depending on their field persistence and toxicity, can contaminate water bodies and may affect living organism. With the objective of determining the effect of field concentrations of Clomazone, Quinclorac, Metsulfuron-methyl and Propanil herbicides on zooplankton community (Cladocers, Copepods and Rotifers, it was carried an experiment in aquaculture ponds, during March to May 2005, in autumn season. In the 1st, 2nd, 3rd, 7th, 10th, 18th, 31th and 51th days after the herbicides application, water samples were collected to evaluate the physical chemical water

  6. Copépodes parasitos de fossas nasais de cinco espécies de peixes (Characiformes da planície de inundação do alto rio Paraná, Paraná, Brasil - DOI: 10.4025/actascibiolsci.v29i4.887 Parasitic copepods in the nasal fossae of five fish species (Characiformes from the upper Paraná river floodplain, Paraná, Brazil - DOI: 10.4025/actascibiolsci.v29i4.887

    Directory of Open Access Journals (Sweden)

    Maria de los Angeles Perez Lizama

    2008-02-01

    Full Text Available O presente trabalho teve como objetivo o estudo de copépodes parasitos de fossas nasais de peixes da planície de inundação do alto Rio Paraná. As coletas foram realizadas em diversos pontos da planície nos meses de março, junho e setembro de 2004. Foram coletados 73 exemplares de peixes da ordem Characiformes, de quatro famílias distintas, pertencentes a cinco espécies: Acestrorhynchus lacustris, Prochilodus lineatus, Schizodon borellii, Serrasalmus maculatus e Serrasalmus marginatus. Dentre os 73 peixes examinados, 53 encontravam-se parasitados por copépodes de fossas nasais, variando de 1 a 146 parasitos por peixe. Os parasitos encontrados pertenciam a três espécies conhecidas: Gamidactylus jaraquensis Thatcher & Boeger, 1984; Gamispatulus schizodontis Thatcher & Boeger, 1984 e Rhinergasilus piranhus Boeger & Thatcher, 1988. Diferenças foram observadas nas medidas corporais dos parasitos e na quantidade de espécies de parasitos por espécie de peixe em relação aos copépodes encontrados em estudos anteriores na região amazônica. O presente estudo constitui um dos poucos trabalhos de identificação de copépodes parasitos de fossas nasais de peixes da região Sul do Brazil.The present work had the objective to study parasitic copepods in the nasal fossae of fish from the upper Paraná river floodplain. Fish were captured in different locations of the floodplain in March, June and September, 2004. A total of 73 specimens (Characiformes were collected, belonging to 4 distinct families and 5 species: Acestrorhynchus lacustris (Acestrorhynchidae, Schizodon borellii (Anostomidae, Prochilodus lineatus (Prochilodontidae, Serrasalmus marginatus and Serrasalmus maculatus (Serrasalmidae. Among 73 fishes examined, 53 were parasitized by nasal fossae copepods, varying from 1 to 146 parasites per host. Parasites found belonged to 3 known species: Gamidactylus jaraquensis Thatcher & Boeger, 1984; Gamispatulus schizodontis Thatcher & Boeger

  7. Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review.

    Science.gov (United States)

    Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel

    2014-01-01

    The studies on marine copepods of Costa Rica started in the 1990's and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance

  8. Diversity of the free-living marine and freshwater Copepoda (Crustacea in Costa Rica: a review

    Directory of Open Access Journals (Sweden)

    Alvaro Morales-Ramírez

    2014-11-01

    Full Text Available The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species, which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic. By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific and 45 from the Caribbean coast (8% of species known from the Caribbean Basin. Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the

  9. Effect of advection on variations in zooplankton at a single location near Cabo Nazca, Peru

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S L; Brink, K H; Santander, H; Cowles, T J; Huyer, A

    1980-04-01

    Temporal variations in the biomass and species composition of zooplankton at a single midshelf station in an upwelling area off Peru can be explained to a large extent by onshore-offshore advection in the upper 20 m of the water column. During periods of strong or sustained near-surface onshore flow, peaks in biomass of zooplankton were observed at midshelf and typically oceanic species of copepod were collected. In periods of offshore flow at the surface, a copepod capable of migrating into oxygen-depleted layers deeper than 30 m was collected. A simple translocation model of advection applied to the cross-shelf distribution of Paracalanus parvus suggests that the fluctuations in P. pavus observed in the midshelf time-series were closely related to onshore-offshore flow in the upper 20 m. Fluctuations in abundance of the numerically dominant copepod, Acartia tonsa, were apparently affected by near surface flow also. The population age-structure suggests that A. tonsa was growing at maximal rates, due in part to its positive feeding response to the dinoflagellate/diatom assemblage of phytoplankton.

  10. Negligible effects of ocean acidification on Eurytemora affinis (Copepoda) offspring production

    Science.gov (United States)

    Almén, Anna-Karin; Vehmaa, Anu; Brutemark, Andreas; Bach, Lennart; Lischka, Silke; Stuhr, Annegret; Furuhagen, Sara; Paul, Allanah; Bermúdez, J. Rafael; Riebesell, Ulf; Engström-Öst, Jonna

    2016-02-01

    Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during 4 consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration and dinoflagellate biomass, had a positive effect. The concentration of polyunsaturated fatty acids in the females was reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

  11. Short term changes in zooplankton community during the summer-autumn transition in the open NW Mediterranean Sea: species composition, abundance and diversity

    Directory of Open Access Journals (Sweden)

    V. Raybaud

    2008-05-01

    Full Text Available Short term changes in zooplankton community were investigated at a fixed station in offshore waters of the Ligurian Sea (Dynaproc 2 cruise, September–October 2004. Mesozooplankton was sampled with vertical WP2 hauls (200 µm mesh-size and large mesozooplankton, macrozooplankton and micronekton with a BIONESS multinet sampler (500 µm mesh-size. Temporal variations of total biomass, species composition and abundance of major taxa were studied. Intrusions of low salinity water masses were observed two times during the cruise. The first one, which was the most important, was associated with changes in zooplankton community composition. Among copepods, the abundance of Calocalanus, Euchaeta, Heterorhabdus, Mesocalanus, Nannocalanus, Neocalanus, Pleuromamma and also calanoid copepodites increased markedly. Among non-copepod taxa, only small ostracods abundance increased. After this low salinity event, abundance of all taxa nearly returned to their initial values. The influence of salinity on each zooplankton taxon was confirmed by a statistical analysis (Perry's method. Shannon diversity index, Pielou evenness and species richness were used to describe temporal variations of large copepod (>500 µm diversity. Shannon index and Pielou evenness decreased at the beginning of the low salinity water intrusions, but not species richness. We suggest that low salinity water masses contained its own zooplankton community and passed through the sampling area, thus causing the replacement of zooplankton population.

  12. Indices of zooplankton community as valuable tools in assessing the trophic state and water quality of eutrophic lakes: long term study of Lake Võrtsjärv

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    Juta Haberman

    2014-03-01

    Full Text Available On the basis of long-term (1964-2011 research, we tested the hypothesis that the zooplankton community has a highly indicative value in assessing the ecosystem and trophic state of water bodies. Basing on the results of our study and taking into account relevant data from numerous zooplankton studies, we can conclude that the zooplankton measures deserving to be used as indicators in the monitoring of Lake Võrtsjärv (and other similar eutrophic water bodies could be the following: i indicatory species of eutrophic waters [Anuraeopsis fissa (Gosse, Keratella tecta (Gosse, Trichocerca rousseleti (Voigt, Chydorus sphaericus (O. F. Müller, Bosmina longirostris (O. F. Müller]; ii indicatory species of oligo-mesotrophic waters [Conochilus unicornis Rousselet, Kellicottia longispina (Kellicott, Ploesoma hudsoni (Imhof, Bosmina berolinensis Imhof, Eudiaptomus gracilis (Sars]; iii number and diversity of species; iv mean zooplankter weight, mean cladoceran weight, mean rotifer weight and mean copepod weight; v rotifer abundance; vi the share (% of rotifers in total zooplankton abundance; vii the ratio of abundance of large cladocerans to abundance of all cladocerans (NLargeClad/NClad; viii the ratio of calanoid copepod abundance to cyclopoid copepod abundance (NCal/NCycl; ix the ratio of crustacean abundance to rotifer abundance (NCrust/NRot . The results of our study show that several zooplankton parameters are among the biological quality elements (BQE deserving to be included in the Water Frame Directive system.

  13. Dispersion and feeding of larval herring ( Clupea harengus L.) in the Moray Firth during September 1985

    Science.gov (United States)

    Heath, M.; Leaver, M.; Matthews, A.; Nicoll, N.

    1989-06-01

    A plume of herring larvae dispersing from a spawning site at Clythness in the Moray Firth (northern Scotland) was surveyed during early September 1985. Several cohorts of larvae were evident from the length distributions, and these were arranged in order of increasing length (age) towards the south-west. The spacing of cohort centres indicated a drift rate of 1-2 km day -1. Calanoid copepod nauplii constituted the major proportion of the diet of larvae <10 mm sampled during the study. Cyclopoid copepod nauplii and gastropod veligers were not found in the diet although they were present in the water. The distribution of nauplii in the region was inversely correlated with the concentration of phytoplankton chlorophyll, and nauplii concentrations were above average in the vicinity of the herring spawning site. The drift trajectory of the herring larvae took them towards an area of high copepodite and adult copepod concentration—items which formed an increasing part of the diet of larger (older) larvae.

  14. Effects of varying food and density on reproduction in Diaptomus clavipes Schacht

    Energy Technology Data Exchange (ETDEWEB)

    Cooney, J.D.; Gehrs, C.W.; Bunting, D.L. II

    1978-05-01

    Experiments were conducted to determine the effects of varying food and density on the egg production of the calanoid copepod, Diaptomus clavipes Schacht. These experiments were performed at both the population and organismic level. An attempt was also made to evaluate the feasibility of using a flow-through system to study the effects of various environmental factors on egg production in copepods. It was found that food supply was an important factor determining rate of clutch production, number of eggs per clutch, and size of individual eggs. As food supply decreased, both the rate of clutch production and the number of eggs per clutch decreased, but the size of individual eggs increased. During periods of extreme food shortage, not only did egg production cease, but also the production of spermatophores by males. When starved females were placed under optimum feeding conditions, they produced eggs within a few days and were producing maximally within two weeks. Egg production in the flow-through system was reduced, due primarily to food shortage. The trout chow solution which was used as food was inadequate because it was not directly utilized by the copepods.

  15. A multi-generation Schmakeria poplesia culturing system for use in ecotoxicological study

    Science.gov (United States)

    Huang, Ying; Zhu, Liyan; Qiu, Xuchun; Qi, Benjin; Zhang, Tianwen

    2009-03-01

    Crustacean zooplankton form the keystone link between primary producers and fish stocks in marine and estuary ecosystems. We have established a multi-generation cultivation system for zooplankton with which future experiments on the biological effects of pollutants in marine and estuary environments can be better performed. A population of calanoid copepod, Schmakeria poplesia, was collected in December 2003 and maintained in a static system through all stages (eggs to adults). The population exhibited an average developmental time of 13.6 d in conditions corresponding to the natural environment (water temperature 20°C, salinity 15). A series of experiments were performed to examine copepod egg production and hatching success as functions of food type and feeding concentration. Results in our study showed that Isochrysis galbana was more favored for the reproduction of copepods than Phaeodactylum tricornutum, and 10×104cells mL-1 was the most practical algae concentration. We have demonstrated that the Schmakeria poplesia population can be maintained in the laboratory through multiple generations. In addition, methods to control egg production through changes in food concentration have been established, making it feasible to control the start date of exposure experiments or the timing of the collection of offspring to initiate a new generation.

  16. A Multi-Generation Schmakeria poplesia Culturing System for Use in Ecotoxicological Study

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; ZHU Liyan; QIU Xuchun; QI Benjin; ZHANG Tianwen

    2009-01-01

    Crustacean zooplankton form the keystone link between primary producers and fish stocks in marine and estuary ecosys-tems. We have established a multi-generation cultivation system for zooplankton with which future experiments on the biological effects of pollutants in marine and estuary environments can be better performed. A population of calanoid copepod, Schmakeria poplesia, was collected in December 2003 and maintained in a static system through all stages (eggs to adults). The population ex-hibited an average developmental time of 13.6d in conditions corresponding to the natural enwronment (water temperature 20℃ salinity 15). A series of experiments were performed to examine copepod egg production and hatching success as functions of food type and feeding concentration. Results in our study showed that Isochrysis galbana was more favored for the reproduction of cope-pods than Phaeodactylum tricornutum, and 10×104cellsmL-1 was the most practical algae concentration. We have demonstrated that the Schmakeria poplesia population can be maintained in the laboratory through multiple generations. In addition, methods to control egg production through changes in food concentration have been established, making it feasible to control the start date of exposure experiments or the timing of the collection of offspring to initiate a new generation.

  17. EVALUATION OF MICRODIETS VERSUS FROZEN COPEPODS ON GROWTH, SURVIVAL AND SELECTED CHEMICAL COMPOSITION OF LARGE YELLOW CROAKER PSEUDOSCIAENA CROCEA LARVAE%微颗粒饲料与冰冻桡足类对大黄鱼稚鱼生长、存活和体成分的影响

    Institute of Scientific and Technical Information of China (English)

    于海瑞; 麦康森; 马洪明; 艾庆辉; 段青源; José Luis Zambonino-Infante; Chantal Louise Cahu

    2012-01-01

    评估三种新开发的微颗粒饲料(Diet 1,Diet 2和Diet 3)、一种混合饲料(Diet 4:Diet 3和冰冻桡足类混合投喂)和冰冻桡足类(Diet 5)对25-60日龄大黄鱼稚鱼的饲喂效果.Diet 1组大黄鱼稚鱼的特定生长率(SGR,7.97%/d)和成活率(40.0%)最高,而Diet 5组稚鱼的SGR(4.15%/d)和成活率(20.4%)最低.Diet4组稚鱼的成活率与Diet 1组差异不显著,但其SGR低于后者.从稚鱼的SGR和成活率看,三种微颗粒饲料中,Diet 1要优于Diet 2和Diet 3.各处理组中每桶稚鱼的生物量与SGR有相似的变化趋势.各微颗粒饲料组稚鱼的体蛋白含量差异不显著,低于Diet 4组,但高于Diet 5组.而微颗粒饲料组稚鱼的脂肪含量(10.6%-13.3%)均显著高于Diet 4组(7.6%)和Diet5组(7.2%).尽管冷冻桡足类中C20:4n-6(AA)的含量稍低于微颗粒饲料,但Diet4和Diet 5组稚鱼的AA含量均显著高于微颗粒饲料组.Diet 4和Diet 5组稚鱼的C22:6n-3(DHA)分别高于其相应饲料中的含量.相反地,微颗粒饲料组稚鱼的C20:5n-3(EPA)低于微颗粒饲料中的含量.这些结果表明,Diet 4和Diet 5组稚鱼体内AA、DHA和EPA的沉积效率高于微颗粒饲料组.研究表明,大黄鱼稚鱼可用微颗粒饲料“断奶”.基于Diet 1优于Diet 2和Diet 3,可将其作为进一步研究的基础配方.此外,有必要对各处理组大黄鱼稚鱼消化酶和消化道的变化进行研究以综合评估微颗粒饲料的效果.%Three newly developed microdiets (MDs:Diet 1,Diet 2 and Diet 3),one co-feeding diet (Diet 4,combined Diet 3 with frozen copepods) and frozen copepods (Diet 5) were tested for weaning large yellow croaker (Pseudosciaena crocea) larvae from 25 to 60 days after hatching (DAH).The highest final specific growth rate (SGR,7.97%/d) and survival (40.0%) were observed in fish fed Diet I,while those were the lowest in fish fed Diet 5 (4.15%/d and 20.4%,respectively).The survival of larvae fed Diet 4 showed no significant

  18. Grazers and phytoplankton growth in the oceans: an experimental and evolutionary perspective.

    Directory of Open Access Journals (Sweden)

    Simona Ratti

    Full Text Available The taxonomic composition of phytoplankton responsible for primary production on continental shelves has changed episodically through Earth history. Geological correlations suggest that major changes in phytoplankton composition correspond in time to changes in grazing and seawater chemistry. Testing hypotheses that arise from these correlations requires experimentation, and so we carried out a series of experiments in which selected phytoplankton species were grown in treatments that differed with respect to the presence or absence of grazers as well as seawater chemistry. Both protistan (Euplotes sp. and microarthropod (Acartia tonsa grazers changed the growth dynamics and biochemical composition of the green alga Tetraselmis suecica, the diatom Thalassiosira weissflogii, and the cyanobacterium Synechococcus sp., increasing the specific growth rate and palatability of the eukaryotic algae, while decreasing or leaving unchanged both parameters in the cyanobacteria. Synechococcus (especially and Thalassiosira produced toxins effective against the copepod, but ciliate growth was unaffected. Acartia induced a 4-6 fold increase of Si cell quota in the diatom, but Euplotes had no similar effect. The differential growth responses of the eukaryotic algae and cyanobacteria to ciliate grazing may help to explain the apparently coeval radiation of eukaryophagic protists and rise of eukaryotes to ecological prominence as primary producers in Neoproterozoic oceans. The experimental results suggest that phytoplankton responses to the later radiation of microarthropod grazers were clade-specific, and included changes in growth dynamics, toxin synthesis, encystment, and (in diatoms enhanced Si uptake.

  19. Zooplankton Hydrodynamics

    DEFF Research Database (Denmark)

    Wadhwa, Navish

    Zooplankton are hugely abundant organisms found in all aquatic environments and form an important part of the marine ecosystems. Most zooplankton swim in order to find food and mates, and to avoid predators. In spite of its advantages, swimming comes with trade-offs, it costs energy and creates...... flow disturbances that may attract predators. The first part of this thesis attempts to quantify the trade-offs associated with the swimming behaviour of diverse zooplankton. We measured the swimming kinematics and flow fields around the 'jumping' copepod Acartia tonsa at various stages of its life...... then measured flows around a wide range of zooplankton which use a variety of swimming modes such as hovering, cruising, jumping, and breast stroke swimming. We found that the spatial decay rate of the flow velocity is dictated by the swimming mode. The modes used for swimming only, such as jumping and breast...

  20. Chemical comparison and acute toxicity of water accommodated fraction (WAF) of source and field collected Macondo oils from the Deepwater Horizon spill.

    Science.gov (United States)

    Faksness, Liv-Guri; Altin, Dag; Nordtug, Trond; Daling, Per S; Hansen, Bjørn Henrik

    2015-02-15

    Two Source oils and five field collected oil residues from the Deepwater Horizon incident were chemically characterized. Water accommodated fractions (WAFs) of the Source oils and two of the field-weathered oils were prepared to evaluate the impact of natural weathering on the chemical composition and the acute toxicity of the WAFs. Toxicity test species representing different tropic levels were used (the primary producer Skeletonema costatum (algae) and the herbivorous copepod Acartia tonsa). The results suggest that the potential for acute toxicity is higher in WAFs from non-weathered oils than WAFs from the field weathered oils. The Source oils contained a large fraction of soluble and bioavailable components (such as BTEX (benzene, toluene, ethyl benzene, xylenes) and naphthalene), whereas in the surface collected oils these components were depleted by dissolution into the water column as the oil rose to the surface and by evaporative loss after reaching the sea surface.