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Sample records for abundant zooplankton taxa

  1. Zooplankton abundance of the Andaman sea

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Achuthankutty, C.T.; Nair, S.R.S.; Nair, V.R.

    the dominant component followed by Chaetognatha and Tunicata Estimates of zooplankton biomass to dry weight and to organic carbon content are made. The average standing crop of zooplankton is 288.8 mg C m2 for the upper 200 m column...

  2. Zooplankton species identities, zooplankton species number per sample, and zooplankton abundance collected using zooplankton net as part of the California Cooperative Fisheries Investigation (CALCOFI) project, for 1994-03-01 (NODC Accession 9700104)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton species identities, zooplankton species number per sample, and zooplankton abundance were collected from March 1, 1994 to March 1, 1994. Data were...

  3. Zooplankton abundance, species composition and ecology of tropical high-mountain crater lake Wonchi, Ethiopia

    Directory of Open Access Journals (Sweden)

    Fasil Degefu

    2014-11-01

    Full Text Available The highlands of Ethiopia represent some of the remnants of undisturbed aquatic ecosystems; they are however highly threatened by significant socio–economic developments and associated anthropogenic impacts. Lake Wonchi is one of the few remaining fairly pristine high–mountain crater lakes in the central highlands and has never been investigated in detail. We present a first study on zooplankton taxa composition, abundance and biomass conducted over more than one year including the underlying environmental drivers. The lake is basic (pH 7.9-8.9, dilute (specific conductivity 185-245 µS cm-1 and oligotrophic with mean trophic status index of 36. The zooplankton community composition showed low species richness comprising a total of fourteen taxa with six cladocerans, one copepod and seven rotifers. Simpson´s index of diversity with values between 0.6 and 0.8 pointed towards a homogenous taxa occurrence within the single sample units. The overall mean (±SD standing biomass of zooplankton was 62.02±25.76 mg dry mass m-3,which is low compared to other highland and rift valley lakes in Ethiopia. Cyclopoid copepods, in particular Thermocyclops ethiopiensis were the most abundant group and contributed 50% to the total zooplankton abundance followed by cladocerans (38% and rotifers (12%. Non-metric multi-dimensional scaling resulted in a 3-dimensional model, which revealed similar community composition on successive sampling dates except in December/January and May. Temperature, alkalinity, conductivity and nitrate-N had significant influence on this seasonal pattern. A weak, but significant positive correlation (r=0.482, N=20, P=0.037 between Chlorophyll a and zooplankton biomass mirrors a bottom-up effect of phytoplankton biomass on zooplankton dynamics. The zooplankton of Lake Wonchi displayed some degree of segregation along the epi– and metalimnion during this study, but diel vertical migration was not observed. The results show that fish

  4. Seasonal variation of zooplankton abundance and community structure in Prince William Sound, Alaska, 2009-2016

    Science.gov (United States)

    McKinstry, Caitlin A. E.; Campbell, Robert W.

    2018-01-01

    Large calanoid copepods and other zooplankters comprise the prey field for ecologically and economically important predators such as juvenile pink salmon, herring, and seabirds in Prince William Sound (PWS).​ From 2009-2016, the Gulf Watch Alaska program collected zooplankton 5-10 times each year at 12 stations in PWS to establish annual patterns. Surveys collected 188 species of zooplankton with Oithona similis, Limacina helicina, Pseudocalanus spp., and Acartia longiremis as the most common species present in 519 samples. Generalized additive models assessed seasonal abundance and showed peak abundance in July (mean: 9826 no. m-3 [95% CI: 7990-12,084]) and lowest abundance in January (503 no. m-3 [373 to 678]). Significantly higher zooplankton abundance occurred in 2010 (542 no. m-3 ± 55 SE) and lowest in 2013 (149 no. m-3 ± 13). The species composition of communities, determined via hierarchical cluster analysis and indicator species analysis, produced six distinct communities based on season and location. The winter community, characterized by warm-water indicator species including Mesocalanus tenuicornis, Calanus pacificus, and Corycaeus anglicus, diverged into four communities throughout the spring and summer. The first spring community, characterized by copepods with affinities for lower salinities, occurred sound-wide. The second spring community, comprised of planktonic larvae, appeared sporadically in PWS bays in 2011-2013. Spring and summer open water stations were defined by the presence of large calanoid copepods. A summer community including the most abundant taxa was common in 2010 and 2011, absent in 2013, then sporadically appeared in 2014 and 2015 suggesting interannual variability of zooplankton assemblages. The zooplankton community shifted to a uniform assemblage characterized by cnidarians in the early autumn. Community assemblages showed significant correlations to a set of environmental variables including SST, mixed layer depth

  5. The northwestern Indian Ocean during the monsoons of 1979: distribution, abundance, and feeding of zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.L.

    1982-01-01

    Upwelling induced by the separation of the Somali Current from the coast of east Africa is associated with low surface temperatures, high concentrations of nitrate, and blooms of phytoplankton. Coefficients of concordance, based upon 17 taxa of zooplankton collected at 33 stations in the southwest monsoon and 15 stations in the northeast monsoon, were consistently larger for the southwest monsoon and indicative of a general response of the zooplankton in the northwestern Indian Ocean. The largest coefficients of concordance in the southwest monsoon were among adult females of Paracalanus denudatus, Paracalanus parvus, and Paracalanus aculeatus and of Calanoides carinatus and Eucalanus spp. Coefficients of concordance among copepodids of six taxa had a trend similar to adult females in the southwest monsoon. During the southwest monsoon, total biomass of zooplankton was significantly greater within areas of upwelling than outside; adult females and copepodids of C. carinatus and Eucalanus spp. were significantly more abundant within the upwelling regions, along with adult females of Clausocalanus furcatus and Clausocalanus minor. The upwelling regions, which are associated with a reproductively active population of the large-bodied C. carinatus, are the primary features affecting distributions of zooplankton during the southwest monsoon and the main difference between monsoons. The ontogenetic migration of C. carinatus is essentially an annual life-history strategy and therefore on the same temporal scale as the reversals in the monsoonal winds and associated upwelling. The ability of C. carinatus to ingest readily the diatoms that dominate the upwelling regions and to store lipid is crucial to its dominance of the areas of upwelling both in numbers and biomass.

  6. Composition and abundance of the zooplankton community in the ...

    African Journals Online (AJOL)

    The taxonomic composition of the zooplankton community of the Bitter Lakes, Egypt, was examined in 2003–2004 in relation to the spatial and temporal distribution of environmental factors. Copepoda were dominant, forming 49% of the zooplankton, followed by Protista at 37%. During the autumn, zooplankton in Small ...

  7. Relative abundance and diel variation of zooplankton from south west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Peter, K.J.

    abundant group, of which calanoids predominated. A swarm of the hydromedusan species, Aequorea conica, (181/m sup(-3)) was seen at night. Quantitative and qualitative variations of various zooplankton groups from six stations in relation to selected physico...

  8. Zooplankton abundance in the River Kars, Northeast Turkey: Impact ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... Turkey: Impact of environmental variables. H. Özbay1* and ... in the river. Key words: River Kars, zooplankton, running water, environmental factors. ..... tergestina (Branchiopoda: Onychopoda) in Guanabara Bay, Brazil. Braz.

  9. Secondary production and zooplankton abundance in the coastal waters from Vengurla to Malpe, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Secondary production and zooplankton abundance in surface and vertical hauls at different stations along 7 transects from Vengurla to Malpe, Maharashtra, India were studied. Zooplankton production varied with the depth of sampling station and type...

  10. Net-zooplankton abundance and biomass from Annaba Bay (SW Mediterranean Sea under estuarine influences

    Directory of Open Access Journals (Sweden)

    M. OUNISSI

    2016-07-01

    Full Text Available Zooplankton samples were collected in Annaba Bay (Algeria from January 2009-March 2011 at three coastal sites differently affected by estuarine plumes and external currents. Aim of this survey was to analyze zooplankton composition, abundance and biomass and compare the results with previous studies to reveal possible populations and environmental changes. The mean zooplankton abundance varied between 1,200-6,000 ind. m-3 and biomass 6.70-25.70 mg DW m-3, according to the site. Copepods constituted the main fraction of zooplankton community, and Oithona similis and Paracalanus indicus successively dominated during autumn-winter and spring-summer. The dinoflagellate Noctiluca scintillans was one of the major zooplankton components, and developed high numbers during February-April, becoming common in neritic and coastal regions. The singularity of the zooplankton from Annaba Bay is the prevalence of P. indicus throughout the entire bay and the decrease in Acartia discaudata and A. clausi (with respect to previous years, possibly replaced by A. negligens. Additionally, Oithona nana abundance markedly decreased with the large development of O. similis. Annaba Bay also differs from other similar Mediterranean coastal areas by the large development of Centropages ponticus populations during the warm period. Among the identified copepod species, the alien species Pseudodiaptomus australiensis and P. arabicus are reported for the first time in the Mediterranean Sea. The occurrence of copepodid V stages of P. australiensis suggests that this species survives and reproduces in Annaba Bay, but so far without developing an abundant population.

  11. Phytoplankton Composition and Abundance in Restored Maltański Reservoir under the Influence of Physico-Chemical Variables and Zooplankton Grazing Pressure.

    Directory of Open Access Journals (Sweden)

    Anna Kozak

    Full Text Available In this paper we present the effects of environmental factors and zooplankton food pressure on phytoplankton in the restored man-made Maltański Reservoir (MR. Two methods of restoration: biomanipulation and phosphorus inactivation have been applied in the reservoir. Nine taxonomical groups of phytoplankton represented in total by 183 taxa were stated there. The richest groups in respect of taxa number were green algae, cyanobacteria and diatoms. The diatoms, cryptophytes, chrysophytes, cyanobacteria, green algae and euglenophytes dominated in terms of abundance and/or biomass. There were significant changes among environmental parameters resulting from restoration measures which influenced the phytoplankton populations in the reservoir. These measures led to a decrease of phosphorus concentration due to its chemical inactivation and enhanced zooplankton grazing as a result of planktivorous fish stocking. The aim of the study is to analyse the reaction of phytoplankton to the restoration measures and, most importantly, to determine the extent to which the qualitative and quantitative composition of phytoplankton depends on variables changing under the influence of restoration in comparison with other environmental variables. We stated that application of restoration methods did cause significant changes in phytoplankton community structure. The abundance of most phytoplankton taxa was negatively correlated with large zooplankton filter feeders, and positively with zooplankton predators and concentrations of ammonium nitrogen and partly of phosphates. However, restoration was insufficient in the case of decreasing phytoplankton abundance. The effects of restoration treatments were of less importance for the abundance of phytoplankton than parameters that were independent of the restoration. This was due to the continuous inflow of large loads of nutrients from the area of the river catchment.

  12. Phytoplankton Composition and Abundance in Restored Maltański Reservoir under the Influence of Physico-Chemical Variables and Zooplankton Grazing Pressure

    Science.gov (United States)

    Kozak, Anna; Gołdyn, Ryszard; Dondajewska, Renata

    2015-01-01

    In this paper we present the effects of environmental factors and zooplankton food pressure on phytoplankton in the restored man-made Maltański Reservoir (MR). Two methods of restoration: biomanipulation and phosphorus inactivation have been applied in the reservoir. Nine taxonomical groups of phytoplankton represented in total by 183 taxa were stated there. The richest groups in respect of taxa number were green algae, cyanobacteria and diatoms. The diatoms, cryptophytes, chrysophytes, cyanobacteria, green algae and euglenophytes dominated in terms of abundance and/or biomass. There were significant changes among environmental parameters resulting from restoration measures which influenced the phytoplankton populations in the reservoir. These measures led to a decrease of phosphorus concentration due to its chemical inactivation and enhanced zooplankton grazing as a result of planktivorous fish stocking. The aim of the study is to analyse the reaction of phytoplankton to the restoration measures and, most importantly, to determine the extent to which the qualitative and quantitative composition of phytoplankton depends on variables changing under the influence of restoration in comparison with other environmental variables. We stated that application of restoration methods did cause significant changes in phytoplankton community structure. The abundance of most phytoplankton taxa was negatively correlated with large zooplankton filter feeders, and positively with zooplankton predators and concentrations of ammonium nitrogen and partly of phosphates. However, restoration was insufficient in the case of decreasing phytoplankton abundance. The effects of restoration treatments were of less importance for the abundance of phytoplankton than parameters that were independent of the restoration. This was due to the continuous inflow of large loads of nutrients from the area of the river catchment. PMID:25906352

  13. Estimates of zooplankton abundance and size distribution with the Optical Plankton Counter (OPC)

    DEFF Research Database (Denmark)

    Wieland, Kai; Petersen, D.; Schnack, D.

    1997-01-01

    The capability of the Optical Plankton Count er (OPC) to examine the abundance and size distribution of zooplankton was tested in Storfjorden, Norway, in June 1993. Selected material obtained from net sampling was measured with a laboratory version of the OPC and compared with microscope analysis...

  14. Relative abundance of resident versus oceanic zooplankton over an interisland reef

    International Nuclear Information System (INIS)

    Alldredge, A.L.; King, J.M.

    1979-01-01

    Zooplankton were collected from various substrate types. Densities were determined and results indicated that demersal plankton were abundant on the Japtan reef flat. Behavioral mechanisms were exhibited by many organisms including swimming near the substrate or in the lees of coral heads. Demersal plankton may provide an important food source for nocturnally foraging fishes

  15. The Arabian Sea: Physical environment, zooplankton and myctophid abundance

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, K.K.C.; Madhupratap, M.; Gopalakrishnan, T.C.; Haridas, P.; Gauns, M.

    that there are considerable spatial and temporal variations in the area in primary productivity. Nonetheless, contrary to earlier thinking, it would seem that the mesozooplankton abundance in the Arabian Sea is fairly high in the mixed layer all through the year. This paradox...

  16. Taxa Composition, Abundance, Distribution And Diversity Of The ...

    African Journals Online (AJOL)

    Forty-eight genera of plankton were recorded; nine of Cyanophyceae, thirteen each of Chlorophyceae and Bacillariophyceae, seven of Protozoa and three each of Rotifera and Crustacea. Members of Cyanophyceae dominated the assemblage accounting for 91.77% of the total plankton abundance. All the major plankton ...

  17. Zooplankton biomass and abundance of Antarctic krill Euphausia superba DANA in Indian Ocean sector of the southern ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Parulekar, A.H.

    Zooplankton sampling was carried out during the first six Indian Scientific Expeditions to Antarctica (1981-1987) to estimate krill abundance in the Indian sector of the Southern Ocean (between 35 to 70 degrees S and 10 to 52 degrees E). This study...

  18. Interannual abundance changes of gelatinous carnivore zooplankton unveil climate-driven hydrographic variations in the Iberian Peninsula, Portugal.

    Science.gov (United States)

    D'Ambrosio, Mariaelena; Molinero, Juan C; Azeiteiro, Ulisses M; Pardal, Miguel A; Primo, Ana L; Nyitrai, Daniel; Marques, Sónia C

    2016-09-01

    The persistent massive blooms of gelatinous zooplankton recorded during recent decades may be indicative of marine ecosystem changes. In this study, we investigated the potential influence of the North Atlantic climate (NAO) variability on decadal abundance changes of gelatinous carnivore zooplankton in the Mondego estuary, Portugal, over the period 2003-2013. During the 11-year study, the community of gelatinous carnivores encompassed a larger diversity of hydromedusae than siphonophores; the former dominated by Obelia spp., Lizzia blondina, Clythia hemisphaerica, Liriope tetraphylla and Solmaris corona, while the latter dominated by Muggiaea atlantica. Gelatinous carnivore zooplankton displayed marked interannual variability and mounting species richness over the period examined. Their pattern of abundance shifted towards larger abundances ca. 2007 and significant phenological changes. The latter included a shift in the mean annual pattern (from unimodal to bimodal peak, prior and after 2007 respectively) and an earlier timing of the first annual peak concurrent with enhanced temperatures. These changes were concurrent with the climate-driven environmental variability mainly controlled by the NAO, which displayed larger variance after 2007 along with an enhanced upwelling activity. Structural equation modelling allowed depicting cascading effects derived from the NAO influence on regional climate and upwelling variability further shaping water temperature. Such cascading effect percolated the structure and dynamics of the community of gelatinous carnivore zooplankton in the Mondego estuary. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Arctic phytoplankton and zooplankton abundance, temperature and salinity measurements collected from multiple platforms from 1903-02-22 to 1970-09-30 (NODC Accession 0069178)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic phytoplankton and zooplankton abundance, temperature and salinity measurements collected from multiple platforms from 1903-02-22 to 1970-09-30 by Zoological...

  20. Chemical, Physical, and zooplankton abundance/biomass data collected using several instruments in the Coastal Waters of California as a part of the California Cooperative Fisheries Investigation (CALCOFI) project, from 07 January 2000 to 01 July 2000 (NODC Accession 0000298)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, physical, and zooplankton abundance/biomass data were collected using secchi disk, zooplankton net, current meter (ADCP), bottle, and CTD casts in the...

  1. Host-specificity among abundant and rare taxa in the sponge microbiome.

    Science.gov (United States)

    Reveillaud, Julie; Maignien, Loïs; Murat Eren, A; Huber, Julie A; Apprill, Amy; Sogin, Mitchell L; Vanreusel, Ann

    2014-06-01

    Microbial communities have a key role in the physiology of the sponge host, and it is therefore essential to understand the stability and specificity of sponge-symbiont associations. Host-specific bacterial associations spanning large geographic distance are widely acknowledged in sponges. However, the full spectrum of specificity remains unclear. In particular, it is not known whether closely related sponges host similar or very different microbiota over wide bathymetric and geographic gradients, and whether specific associations extend to the rare members of the sponge microbiome. Using the ultra-deep Illumina sequencing technology, we conducted a comparison of sponge bacterial communities in seven closely related Hexadella species with a well-resolved host phylogeny, as well as of a distantly related sponge Mycale. These samples spanned unprecedentedly large bathymetric (15-960 m) gradients and varying European locations. In addition, this study included a bacterial community analysis of the local background seawater for both Mycale and the widespread deep-sea taxa Hexadella cf. dedritifera. We observed a striking diversity of microbes associated with the sponges, spanning 47 bacterial phyla. The data did not reveal any Hexadella microbiota co-speciation pattern, but confirmed sponge-specific and species-specific host-bacteria associations, even within extremely low abundant taxa. Oligotyping analysis also revealed differential enrichment preferences of closely related Nitrospira members in closely related sponges species. Overall, these results demonstrate highly diverse, remarkably specific and stable sponge-bacteria associations that extend to members of the rare biosphere at a very fine phylogenetic scale, over significant geographic and bathymetric gradients.

  2. Methane anomalies in the oxygenated upper waters of the central Baltic Sea associated with zooplankton abundance

    Science.gov (United States)

    Schmale, Oliver; Wäge, Janine; Morholz, Volker; Rehder, Gregor; Wasmund, Norbert; Gräwe, Ulf; Labrenz, Matthias; Loick-Wilde, Natalie

    2017-04-01

    Apart from the sediment as the dominant source of methane in the aquatic realm the process of methane production in well-oxygenated waters has received considerable attention during the last years. The paradox of methane accumulation in these relatively shallow waters, commonly termed as "oceanic methane paradox", has been sporadically observed in lakes as well as in marine ecosystems like the Gulf of Mexico, the Black Sea, the Baltic Sea, Arctic waters or above the continental shelf off the coast of Spain and Africa. Even if this phenomenon has been described in the literature over the last decades, the potential sources of shallow methane accumulation are still controversially discussed. We report on methane enrichments that were observed during summer in the upper water column of the Gotland Basin, central Baltic Sea. In the eastern part of the basin methane concentrations just below the thermocline (in about 30 m water depth) varied between 15 and 77 nM, in contrast to the western part of the basin where no methane enrichments could be detected. Stable carbon isotope ratios of methane (delta 13C-CH4 of -67.6‰) clearly indicated its in situ biogenic origin. This is supported by clonal sequences from the depth with high methane concentrations in the eastern Gotland Basin, which cluster with the clade Methanomicrobiacea, a family of methanogenic Archaea. Hydroacoustic observation in combination with plankton net tows displayed a seston enrichment (size >100 micro meter) in a layer between 30-50 m depth. The dominant species in the phytoplankton, Dinophysis norvegica, was concentrated at 10-20 m depth, and showed higher concentrations in the eastern Gotland Basin in comparison with the western part of the basin. In contrast to the western Gotland Basin, the zooplankton community in the eastern part was dominated by the copepod species Temora longicornis. Laboratory incubations of a T. longicornis dominated seston fraction (>100 micro meter) sampled in the depth

  3. Seasonal variations of species composition and abundance of zooplankton in Ehoma Lake, a floodplain lake in Nigeria

    Directory of Open Access Journals (Sweden)

    Okechukwu. I Okogwu

    2010-03-01

    Full Text Available Ehoma Lake is among the important breeding sites of the major fishes in the Mid-Cross River, Nigeria. The juveniles of these fishes are solely dependent on zooplankton, which has not been studied previously. I studied monthly the lake’s physico-chemical variables and zooplankton composition in three stations (littoral, sub-littoral and pelagic from March 2005 to August 2006. Sixty-seven zooplankton species (42 rotifers, 19 cladocerans and 6 copepods were identified. Daphnia obtusa Kurz, Keratella valga Ehrenberg, Keratella ticinensis Callerrio, Keratella hiemalis Carlin, Brachionus dimidiatus Bryce and Lecane candida Hauer and Murray are new records for Nigeria. The dominant zooplankters were Diaphanosoma excisum Kurz and Moina micrura Kurz. There was an inverse relationship between species richness and abundance. Richness was highest in the dry season while peak zooplankton abundance was recorded in the rainy season. Zooplankton abundance and species richness decreased progressively from the littoral to the pelagic station while the Shannon-Weaver diversity index varied from 0.68 to 1.28 without a clear seasonal trend. There is a succession pattern: rotifers that are dominant in the dry season are replaced by cladocerans in the rainy season. This succession was greatly influenced by seasonal flooding of the lake. As no previous information on the zooplankton of the lake is available, this study provides baseline data on the lake`s zooplankton. Rev. Biol. Trop. 58 (1: 171-182. Epub 2010 March 01.El lago Ehoma, situado en la mitad del río Cross, es uno de los lugares de reproducción de las principales especies de peces del río. Los juveniles de estos peces dependen exclusivamente del zooplancton, sin embargo poco se sabe sobre este recurso en el lago. En este estudio, las variables físico-químicas y del zooplancton del lago fueron estudiadas mensualmente en tres estaciones (litoral, sub-litoral y pelágica, de marzo de 2005 a agosto de

  4. Variación diaria de la abundancia del zooplancton en Bahía Magdalena, B.C.S. México Daily cycle of zooplankton abundance in Magdalena Bay, B.C.S. Mexico

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    Sergio Hernández-Trujillo

    2010-12-01

    Full Text Available Se presenta la variación diaria de la abundancia de zooplancton en Bahía Magdalena, México a partir de muestreos en una estación fija durante 10 días en febrero de 2002. De 112 taxa identificados, los nauplios de balanos y los cladóceros Penilia avirostris y Pseudevadne tergestina fueron los más comunes y abundantes y con niveles de variación diaria de más del 100%. Los copépodos constituyeron una quinta parte de la abundancia del zooplancton y 7 de las 80 especies encontradas se registran por vez primera en la zona de estudio. La abundancia del zooplancton fue parcialmente coherente con la hidrografía de la bahía, así como con un modelo de retención de partículas. Las 3 especies de copépodos más abundantes fueron más numerosas a inicio de la serie pero tendieron a reducir su densidad hacia el fin del lapso de estudio. La hidrodinámica invernal en la zona se identificó como un factor de concentración de zooplancton, quizá de importancia mayor que la temperatura o la concentración de clorofila a, aún no estimada en la estructura de la comunidad ni en la intensidad de las relaciones interespecíficas.This paper presents the daily variation of the abundance of zooplankton in Magdalena Bay, Mexico from sampling in a fixed-station for 10 days of February 2002. From 112 taxa identified barnacles nauplii and cladocerans Penilia avirostris and Pseudevadne tergestina were the most common and abundant with daily variation levels more than 100%. The copepods constituted one fifth of zooplankton abundance and 7 of the 80 species found were recorded for the first time in the study area. Zooplankton abundance showed partially coherent pattern with the hidrography of the bay as well as particles retention model. The 3 species of copepods more abundant were more numerous at the beginning of the time series but tended to reduce its density toward the end of the time of study. Winter hydrodynamics was identified as a factor of zooplankton

  5. Micro-zooplankton and its abundance relative to the larger zooplankton and other seston components, 08 February 1967 to 27 February 1967 (NODC Accession 0000916)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Micro-zooplankton populations in the upper 100 m were sampled from 5 marine environments in the northeast Pacific Ocean extending from slope waters off San Diego to...

  6. Composition and abundance of zooplankton groups from a coral reef lagoon in Puerto Morelos, Quintana Roo, Mexico, during an annual cycle.

    Science.gov (United States)

    Alvarez-Cadena, José N; Ordóñez-López, Uriel; Almaral-Mendivil, Alma Rosa; Uicab-Sabido, Amira

    2009-09-01

    Zooplankton sampling was carried out monthly from January to December 1990 at station A near the coastline, and station B near the reef barrier, in a tropical coral reef lagoon in the Mexican Caribbean Sea. Samplings were made at midnight, near surface, with a conical net (mouth 0.40 m, mesh 330 microm) for 10 min. Salinity varied from 35.1 to 36.3 psu and temperature from 26.3 to 30.2 degrees C. The Bray-Curtis test applied to these results has defined two seasons: the dry season from November to May, and the wet season from June to October. A total of 37 zooplankton groups were found. Copepods were the most abundant contributing 49.0% of the total capture with Acartia espinata, Calanopia americana and Farranula gracilis as the most numerous. In the total zooplankton, however, cirripeds captured in only 15 samples of 24 were second in abundance (20.9%). Decapods, present all year-round and more abundant during the wet season, were third and contributed 19.2%. The rest of the groups were scarce and only amphipods (2.4%) and larvaceans (2.0%) were relatively abundant. The abundance of captured organisms correlated with the abiotic factors measured, thus, in the dry season, abundance was lower (mean 7.3 orgs/m3), while in the wet season the mean catch was 36.8 orgs/m3.

  7. Colonization of marine snow aggregates by invertebrate zooplankton : Abundance, scaling, and possible role

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2000-01-01

    I compiled literature observations of abundances of invertebrate zooplankters associated with marine snow aggregates in the euphotic zone. Abundances, normalized with ambient concentrations of colonizers, scale with equivalent aggregate radius raised to power 2.27. Different taxonomic groups showed...... different affinities for aggregates and copepods and crustacean nauplii were the dominant groups on aggregates. The encounter volumes (volume searched to find one aggregate) are substantial, e.g., >1 liter for a l-cm aggregate, suggesting that some zooplankters actively search for aggregates. The scaling...

  8. Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

    NARCIS (Netherlands)

    Kouwenberg, Juliana H.M.

    1993-01-01

    Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish

  9. Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México

    OpenAIRE

    Roberto E. Torres-Orozco B.; Sandra A. Zanatta

    1998-01-01

    From April 1992 to May 1993, zooplankton samples were collected monthly by means of horizontal tows in nine sites of the lake. Prior to the towing, temperature of surface water, transparency (Secchi), pH and dissolved oxygen were evaluated. A total of 31 zooplankton forms, including 14 species of rotifers, three copepods, five cladocerans and one ostracod, as well as protozoans (mainly vorticellids and ciliates), were detected. Rotifers were the dominant organisms, mainly Brachionus havanaens...

  10. Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México

    Directory of Open Access Journals (Sweden)

    Roberto E. Torres-Orozco B.

    1998-06-01

    Full Text Available From April 1992 to May 1993, zooplankton samples were collected monthly by means of horizontal tows in nine sites of the lake. Prior to the towing, temperature of surface water, transparency (Secchi, pH and dissolved oxygen were evaluated. A total of 31 zooplankton forms, including 14 species of rotifers, three copepods, five cladocerans and one ostracod, as well as protozoans (mainly vorticellids and ciliates, were detected. Rotifers were the dominant organisms, mainly Brachionus havanaensis (27.6 ind l-¹, B. angularis (6.9 ind l-¹, Keratella cochlearis (4.9 ind l-¹, Conochilus unicornis (10.8 ind l-¹ and C. dossuarius (3.1 ind l-¹. Within crustaceans, higher densities were shown by larvae (nauplii and copepodites of calanoid (16.8 ind l-¹ and cyclopoid (15.6 ind l-¹ copepods, as well as Arctodiaptomus dorsalis (2 ind l-¹, Mesocyclops edax (0.5 ind l-¹, and the cladocerans Bosmina longirostris (1.6 ind l-¹ and Diaphanosoma brachyurum (0.5 ind l-¹. Densities were low, probably because of a high predation pressure imposed by fishes. A gradual increase in total zooplankton density related with a progressive diminution of transparency was observed throughout the sampling period. Zooplankton densities in the stations located at the central part of the lake were higher when compared with those at a more peripheral position. Time variation in rotifer's relative abundance was directly related to temperature fluctuations. The low density and diversity values, the small size of the zooplankters, the presence of an important number of indicator species, and the calanoid copepods: other planktonic crustaceans low ratio, are all indicators of eutrophy. Evidences suggest that the eutrophication process of Lake Catemaco is still progressing rapidly.Entre abril de 1992 y mayo de 1993, se realizaron mensualmente recolectas subsuperficiales de zooplancton, con red, en nueve localidades del lago, en donde también se determinaron la temperatura

  11. Zooplankton body composition

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2013-01-01

    groups body composition is size independent. Exceptions are protozoans, chaetognaths, and pteropods, where larger individuals become increasingly watery. I speculate about the dichotomy in body composition and argue that differences in feeding mechanisms and predator avoidance strategies favor either......I compiled literature on zooplankton body composition, from protozoans to gelatinous plankton, and report allometric relations and average body composition. Zooplankton segregate into gelatinous and non-gelatinous forms, with few intermediate taxa (chaetognaths, polychaetes, and pteropods). In most...... a watery or a condensed body form, and that in the intermediate taxa the moderately elevated water content is related to buoyancy control and ambush feeding...

  12. Latitudinal environmental gradients and diel variability influence abundance and community structure of Chaetognatha in Red Sea coral reefs

    KAUST Repository

    Al-aidaroos, Ali M.; Karati, Kusum K.; El-sherbiny, Mohsen M.; Devassy, Reny P.; Kü rten, Benjamin

    2016-01-01

    is known about the zooplankton biodiversity of the Red Sea and how this relates to Red Sea latitudinal gradients. Among the most abundant zooplankton taxa are Chaetognatha, which play an important role as secondary consumers in most marine food webs. Since

  13. Fine-scale distribution of zooplankton is linked to phytoplankton species composition and abundance in a North Norwegian fjord system

    Science.gov (United States)

    Norrbin, F.; Priou, P. D.; Varela, A. P.

    2016-02-01

    We studied the influence of dense layers of phytoplankton and aggregates on shaping the vertical distribution of zooplankton in a North Norwegian fjord using a Video Plankton Recorder (VPR). This instrument provided fine-scale vertical distribution (cm-m scale) of planktonic organisms as well as aggregates of marine snow in relation to environmental conditions. At the height - later stage of the spring phytoplankton bloom in May, the outer part of the fjord was dominated by Phaeocystis pouchetii, while diatoms (Chaetoceros spp.) were dominating in the innermost basin. Small copepods species like Pseudocalanus spp., Microsetella norvegica, and Oithona spp. prevailed over larger copepod species in the inner part of the fjord whereas the outer part was dominated by large copepods like Calanus finmarchicus. While the zooplankton where spread out over the water column during the early stage of the bloom, in May they were linked to the phytoplankton vertical distribution and in the winter situation they were found in deeper waters. Herbivorous zooplankton species were affected by phytoplankton species composition; C. finmarchicus and Pseudocalanus spp. avoided the dense layer of P. pouchetii while herbivorous zooplankton matched the distribution of the diatom-dominated bloom. Small, omnivorous copepod species like Microsetella sp., Oithona sp. and Pseudocalanus sp. were often associated with dense layers of snow aggregates. This distribution may provide a shelter from predators as well as a food source. Natural or anthropogenic-induced changes in phytoplankton composition and aggregate distribution may thus influence food-web interactions.

  14. Zooplankton community response to experimental acidification in boreal shield lakes with different ecological histories

    Energy Technology Data Exchange (ETDEWEB)

    Derry, A.M.; Arnott, S.E. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology

    2007-06-15

    This study investigated the adaptive response of crustacean zooplankton to widespread regional acidification at the Killarney Provincial Park in Ontario. Mesocosm experiments were conducted in 2 circumneutral lakes with different acidification histories. A reciprocal transplant field enclosure experiment was conducted to assess whether the zooplankton community within the acid-recovering boreal shield lake showed evidence of increased acid tolerance to historical acidification following a 6 year period in which the lake's pH was 6.0. The enclosures were filled with epilimnetic water from the lake. Zooplankton from other lakes in the area were used. Zooplankton and water samples were collected from the enclosures once a week. Shannon-Wiener indices, species richness, and total abundance of the zooplankton were calculated for each sample day. Repeated measures analyses of variance (RM-ANOVAs) were used to test for the effects of the incubation lake, the zooplankton source, and the pH. Species abundance data were log{sub 10} transformed to improve homogeneity of variances and normality. Principle components analysis was conducted on species abundances to infer the influence of treatments on zooplankton community composition. Zooplankton were also transferred from 1 lake to the other in order to determine if subtle differences in local water chemistry and food conditions were limiting the recovery of species in acid-recovering lakes. The study showed that 2 key species, H. gibberum and L. minutus, contributed to community-level differences to acid tolerance of zooplankton with different acidification histories. It was concluded that zooplankton with adaptable acid tolerances may monopolize resources in acidified and acid-recovering lakes, and may contribute to the delayed recolonization of other taxa. 62 refs., 3 tabs., 6 figs.

  15. Microbial community diversities and taxa abundances in soils along a seven-year gradient of potato monoculture using high throughput pyrosequencing approach.

    Directory of Open Access Journals (Sweden)

    Xing Liu

    Full Text Available BACKGROUND: Previous studies have focused on linking soil community structure, diversity, or specific taxa to disturbances. Relatively little attention has been directed to crop monoculture soils, particularly potato monoculture. Information about microbial community changes over time between monoculture and non-monoculture treatments is lacking. Furthermore, few studies have examined microbial communities in potato monoculture soils using a high throughput pyrosequencing approach. METHODOLOGY/PRINCIPAL FINDINGS: Soils along a seven-year gradient of potato monoculture were collected and microbial communities were characterized using high throughput pyrosequencing approach. Principal findings are as follows. First, diversity (H(Shannon and richness (S(Chao1 indices of bacterial community, but not of fungal community, were linearly decreased over time and corresponded to a decline of soil sustainability represented by yield decline and disease incidence increase. Second, Fusarium, the only soilborne pathogen-associated fungal genus substantially detected, was linearly increased over time in abundance and was closely associated with yield decline. Third, Fusarium abundance was negatively correlated with soil organic matter (OM and total nitrogen (TN but positively with electrical conductivity (EC. Fourth, Fusarium was correlated in abundances with 6 bacterial taxa over time. CONCLUSIONS: Soil bacterial and fungal communities exhibited differential responses to the potato monoculture. The overall soil bacterial communities were shaped by potato monoculture. Fusarium was the only soilborne pathogen-associated genus associated with disease incidence increase and yield decline. The changes of soil OM, TN and EC were responsible for Fusarium enrichment, in addition to selections by the monoculture crop. Acidobacteria and Nitrospirae were linearly decreased over time in abundance, corresponding to the decrease of OM, suggesting their similar

  16. Composition and abundance of zooplankton groups from a coral reef lagoon in Puerto Morelos, Quintana Roo, Mexico, during an annual cycle

    Directory of Open Access Journals (Sweden)

    José N Álvarez-Cadena

    2009-09-01

    Full Text Available Zooplankton sampling was carried out monthly from January to December 1990 at station A near the coastline, and station B near the reef barrier, in a tropical coral reef lagoon in the Mexican Caribbean Sea. Samplings were made at midnight, near surface, with a conical net (mouth 0.40 m, mesh 330 µm for 10 min. Salinity varied from 35.1 to 36.3 psu and temperature from 26.3 to 30.2 ºC. The Bray-Curtis test applied to these results has defined two seasons: the dry season from November to May, and the wet season from June to October. A total of 37 zooplankton groups were found. Copepods were the most abundant contributing 49.0% of the total capture with Acartia espinata, Calanopia americana and Farranula gracilis as the most numerous. In the total zooplankton, however, cirripeds captured in only 15 samples of 24 were second in abundance (20.9%. Decapods, present all year-round and more abundant during the wet season, were third and contributed 19.2%. The rest of the groups were scarce and only amphipods (2.4% and larvaceans (2.0% were relatively abundant. The abundance of captured organisms correlated with the abiotic factors measured, thus, in the dry season, abundance was lower (mean 7.3 orgs/m3, while in the wet season the mean catch was 36.8 orgs/m3. Rev. Biol. Trop. 57 (3: 647-658. Epub 2009 September 30.Se efectuaron muestreos mensuales de zooplancton en el Caribe de México de enero a diciembre de 1990 en dos estaciones en la laguna arrecifal de Puerto Morelos en el estado de Quintana Roo, una situada cerca de la línea de costa (A, y la otra próxima a la barrera de coral (B. Los arrastres se realizaron en condiciones de oscuridad (a medianoche, cerca de la superficie durante 10 min con una red cónica de boca de 0.40 m y malla de 330 micras. La salinidad varió de 35.1 a 36.3 ups y la temperatura de 26.3 a 30.2 oC. La prueba de Bray-Curtis definió dos épocas en el año, la de secas de noviembre a mayo, y la de lluvias de junio a

  17. Acoustic discrimination of Southern Ocean zooplankton

    Science.gov (United States)

    Brierley, Andrew S.; Ward, Peter; Watkins, Jonathan L.; Goss, Catherine

    Acoustic surveys in the vicinity of the sub-Antarctic island of South Georgia during a period of exceptionally calm weather revealed the existence of a number of horizontally extensive yet vertically discrete scattering layers in the upper 250 m of the water column. These layers were fished with a Longhurst-Hardy plankton recorder (LHPR) and a multiple-opening 8 m 2 rectangular mid-water trawl (RMT8). Analysis of catches suggested that each scattering layer was composed predominantly of a single species (biovolume>95%) of either the euphausiids Euphausia frigida or Thysanöessa macrura, the hyperiid amphipod Themisto gaudichaudii, or the eucalaniid copepod Rhincalanus gigas. Instrumentation on the nets allowed their trajectories to be reconstructed precisely, and thus catch data to be related directly to the corresponding acoustic signals. Discriminant function analysis of differences between mean volume backscattering strength at 38, 120 and 200 kHz separated echoes originating from each of the dominant scattering layers, and other signals identified as originating from Antarctic krill ( Euphausia superba), with an overall correct classification rate of 77%. Using echo intensity data alone, gathered using hardware commonly employed for fishery acoustics, it is therefore possible to discriminate in situ between several zooplanktonic taxa, taxa which in some instances exhibit similar gross morphological characteristics and have overlapping length- frequency distributions. Acoustic signals from the mysid Antarctomysis maxima could also be discriminated once information on target distribution was considered, highlighting the value of incorporating multiple descriptors of echo characteristics into signal identification procedures. The ability to discriminate acoustically between zooplankton taxa could be applied to provide improved acoustic estimates of species abundance, and to enhance field studies of zooplankton ecology, distribution and species interactions.

  18. Vertical and horizontal distribution of zooplankton and polar cod in southern Baffin Bay (66-71°N) in September 2009

    DEFF Research Database (Denmark)

    Kjellerup, Sanne; Dünweber, Michael; Møller, Eva Friis

    2015-01-01

    Zooplankton are the link connecting primary producers to higher trophic levels, and knowing their distribution and community is important for predicting the distribution of predator species, like fish, seabirds, and marine mammals. However, data from open Arctic oceans are still scarce. In autumn...... fishes in the upper 500 m of southern Baffin Bay in September 2009. The zooplankton community was dominated by copepods (55 % of abundance in the upper 500 m), primarily of the genus Calanus. Other important zooplankton taxa included Limacina helicina, Chaetognatha, and Cirripedia nauplii...

  19. The effects of juvenile American shad planktivory on zooplankton production in Columbia River food webs

    Science.gov (United States)

    Haskell, Craig A.; Tiffan, Kenneth F.; Rondorf, Dennis W.

    2013-01-01

    Columbia River reservoirs support a large population of nonnative American Shad Alosa sapidissima that consume the zooplankton that native fishes also rely on. We hypothesized that the unprecedented biomass of juvenile American Shad in John Day Reservoir is capable of altering the zooplankton community if these fish consume a large portion of the zooplankton production. We derived taxon-specific estimates of zooplankton production using field data and a production model from the literature. Empirical daily ration was estimated for American Shad and expanded to population-level consumption using abundance and biomass data from hydroacoustic surveys. Daphnia spp. production was high in early summer but declined to near zero by September as shad abundance increased. American Shad sequentially consumed Daphnia spp., copepods, and Bosmina spp., which tracked the production trends of these taxa. American Shad evacuation rates ranged from 0.09 to 0.24/h, and daily rations ranged from 0.008 to 0.045 g·g−1·d−1 (dry weight) over all years. We observed peak American Shad biomass (45.2 kg/ha) in 1994, and daily consumption (1.6 kg/ha) approached 30% (5.3 kg/ha) of zooplankton production. On average, American Shad consumed 23.6% of the available zooplankton production (range, food web in John Day Reservoir, potentially affecting native fishes, including Pacific salmon Oncorhynchus spp.

  20. Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments

    Science.gov (United States)

    Yang, Sizhong; Wen, Xi; Shi, Yulan; Liebner, Susanne; Jin, Huijun; Perfumo, Amedea

    2016-01-01

    Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeline prior to and after perturbation with crude oil. We found that crude oil caused a decrease of cell numbers together with a reduction of the species richness and shifts in the dominant phylotypes, while bacterial community diversity was highly site-specific after exposure to crude oil, reflecting different environmental conditions. Keystone taxa that strongly co-occurred were found to form networks based on trophic interactions, that is co-metabolism regarding degradation of hydrocarbons (in contaminated samples) or syntrophic carbon cycling (in uncontaminated samples). With this study we demonstrate that after severe crude oil contamination a rapid establishment of endemic hydrocarbon degrading communities takes place under favorable temperature conditions. Therefore, both endemism and trophic correlations of bacterial degraders need to be considered in order to develop effective cleanup strategies. PMID:27886221

  1. Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River

    Science.gov (United States)

    Haskell, C.A.; Tiffan, K.F.; Rondorf, D.W.

    2006-01-01

    As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in zooplankton abundance were largely due to differences in water temperature and flow. Spatial variation in total zooplankton abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied zooplankton. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.

  2. Variabilidad de la abundancia de zooplancton en Bahía Magdalena Baja California Sur, México (1997-2001 Zooplankton abundance variability in Magdalena Bay, Baja California Sur, Mexico (1997-2001

    Directory of Open Access Journals (Sweden)

    Sergio Hernández-Trujillo

    2010-01-01

    Full Text Available Se analizaron muestras de zooplancton de 16 campañas oceanógraficas, efectuadas en Bahía Magdalena, Baja California Sur, México, entre agosto de 1997 y marzo de 2001. Se identificó un total de 26 grupos taxonómicos, de los cuales los más abundantes y frecuentes fueron copépodos y quetognatos; en 2000-2001 se observó una tendencia a disminuir entre 10 y 20 el número de grupos de zooplancton. La biomasa zooplanctónica y abundancia de copépodos disminuyeron en el periodo de estudio, en contraste con los quetognatos que tuvieron un ligero aumento. Las fluctuaciones de abundancia de zooplancton no estuvieron relacionadas con la concentración de clorofila-α, a diferencia de los máximos de abundancia de zooplancton, que estuvieron asociados a los cambios de la temperatura superficial del mar. El ciclo estacional de la abundancia del zooplancton en Bahía Magdalena, indicó que en invierno el promedió fue mayor de 65.000 ind 100 m-3 , valor que aumentó en primavera a más de 99.000 ind 100 m-3 , se mantuvo en verano alrededor de 100.000 ind 100 m-3 y en otoño descendió rápidamente a casi 40.000 ind 100 m-3.Zooplankton were studied from 16 oceanographic surveys carried out in Magdalena Bay, Baja California Sur, Mexico, between August 1997 and March 2001. Twenty-six taxonomic groups were identified, the most abundant and frequent of which were copepods and chaetognaths. In 2000-2001, the number of zooplankton groups tended to decrease by 10 to 20. Both zooplankton biomass and copepod abundance declined, unlike chaetognaths, which increased slightly. Fluctuations in zooplankton abundance were independent of the chlorophyll-a concentration, whereas the maximum zooplankton abundances were associated with changes in the sea surface temperature. The seasonal zooplankton abundance cycle in Magdalena Bay indicated that, in winter, the averaged was than 65,000 ind 100 m-3 , a value that increased to more than 99,000 ind 100 m-3 in spring

  3. 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

  4. Zooplankton variability in polluted and unpolluted waters off Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Desai, B.N.

    Zooplankton abundance in the waters around Bombay was studied at Versova, Bombay Harbour (less polluted), Mahim and Thana (highly polluted) from October 1977 to December 1978. A rich zooplankton population was observed throughout the period of study...

  5. Annual variations in zooplankton from a polluted coastal environment

    Digital Repository Service at National Institute of Oceanography (India)

    Haridas, P.; Menon, P.G.; Madhupratap, M.

    Seasonal changes in the composition and distribution of zooplankton from the coastal waters of Trivandrum were studied. The study indicated that the effluent discharged from a nearby titanium dioxide factory did not affect the zooplankton abundance...

  6. Rapid reassessment of the eutrophication status of Kingston Harbour, Jamaica using the zooplankton community

    Directory of Open Access Journals (Sweden)

    Patrice A. Francis

    2014-09-01

    Full Text Available Previous extensive studies of zooplankton distribution in the eutrophic Kingston Harbour established that it was being continuously contaminated. We assessed the community in 2011, 17 years after a previous study and five years after the introduction of a tertiary waste water system. Sampling was conducted for four weeks at eight stations identical to those sampled in a previous study. We used horizontal surface tows with a 200µm net. A total of 73 zooplankton taxa were identified and copepods dominated with 20 species. Mean total abundances were high, ranging from a minimum of 2 383 animals m-3 in the southern region of Hunts Bay to 194 166 animals m-3at the Inner Harbour. Five zooplankton taxa (Acartia tonsa, Paracalanus spp., Temora turbinata, Penilia avirostris and Lucifer faxoni that were previously identified as indicators, were again important in the Harbour. The overall zooplankton abundances were similar and in some cases higher than the previous study. There was no significant improvement in the water quality since the introduction of the treatment system at Soapberry. This may be a result of unknown nutrient inputs or of nutrient remaining in the sediments.

  7. Correspondence of zooplankton assemblage and water quality in wetlands of Cachar, Assam, India: Implications for environmental management

    Directory of Open Access Journals (Sweden)

    Kar Sulata

    2018-03-01

    Full Text Available The zooplankton assemblage of selected wetlands of Assam, India was assessed to deduce the structural variation in the context of water quality parameters. A two year study between 2012 and 2014 comprising of 530 samples from the five wetlands revealed the presence of 46 taxa, 26 Rotifera, 15 Cladocera, 4 Copepoda and 1 Ostracoda, in varying density. The rotifers dominated in terms of abundance (48 ind. cm−3 followed by the cladocerans (28 ind. cm−3 and the copepods (19 ind. cm−3 and showed significant (p <0.05 correlations with turbidity, alkalinity, hardness and phosphate contents of the water samples. The diversity and the richness of the zooplankton showed an increasing trend with the water temperature. Among the different taxa, Brachionus sp. was most abundant followed by Mesocyclops sp. while Beauchampiella sp. was represented in the least numbers. Application of the cluster analysis allowed the segregation of the different zooplankton based on the similarities of abundance in the samples. The water quality parameters like temperature, alkalinity, turbidity, magnesium and calcium were observed to be significant contributors in shaping the zooplankton community composition of the wetlands, revealed through the correlations and canonical correspondence analysis. As an extension, the information can be used in monitoring the quality of the freshwater habitats of the concerned and similar geographical regions, using the zooplankton as the major constituents. The variations in the abundance of cladoceran, copepod and rotifer zooplanktons can be used to understand the mechanisms that sustain the food webs of the aquatic community of the freshwater bodies.

  8. Seasonal dynamics of zooplankton in Columbia–Snake River reservoirs,with special emphasis on the invasive copepod Pseudodiaptomus forbesi

    Science.gov (United States)

    Emerson, Joshua E.; Bollens, Stephen M.; Counihan, Timothy D.

    2015-01-01

    The Asian copepod Pseudodiaptomus forbesi has recently become established in the Columbia River. However, little is known about its ecology and effects on invaded ecosystems. We undertook a 2-year (July 2009 to June 2011) field study of the mesozooplankton in four reservoirs in the Columbia and Snake Rivers, with emphasis on the relation of the seasonal variation in distribution and abundance of P. forbesi to environmental variables. Pseudodiaptomus forbesi was abundant in three reservoirs; the zooplankton community of the fourth reservoir contained no known non-indigenous taxa. The composition and seasonal succession of zooplankton were similar in the three invaded reservoirs: a bloom of rotifers occurred in spring, native cyclopoid and cladoceran species peaked in abundance in summer, and P. forbesi was most abundant in late summer and autumn. In the uninvaded reservoir, total zooplankton abundance was very low year-round. Multivariate ordination indicated that temperature and dissolved oxygen were strongly associated with zooplankton community structure, with P. forbesi appearing to exhibit a single generation per year . The broad distribution and high abundance of P. forbesi in the Columbia–Snake River System could result in ecosystem level effects in areas intensively managed to improve conditions for salmon and other commercially and culturally important fish species. 

  9. Surface zooplankton communities in the Indian sector of the Antarctic Ocean in early summer 1999/2000 observed with a Continuous Plankton Recorder

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    Haruko Umeda

    2018-05-01

    Full Text Available The first deployment of a Continuous Plankton Recorder (CPR on board the icebreaker Shirase was conducted during the 41st Japanese Antarctic Research Expedition (JARE in 1999/2000 austral summer in the Indian sector of the Antarctic Ocean. The CPR was towed horizontally at approximately 10m depth while the Shirase was steaming at about 14 knots across the Polar Front (PF. Mean total abundance of zooplankton for horizontal five nautical mile sample units was 168.1(SD : ±117.18 individuals with the maximum of 456 individuals. Zooplanktons were counted for 34 categories of species/taxa. Copepods occupied more than 90% of the total abundance in numbers. Oithona spp. was the most dominant group among copepods, representing 59% of the total zooplankton. Other numerically important categories were small-sized calanoids (copepodites and adults; 18.4%, and copepodites of Calanoides acutus and Calanus simillimus (8.2%. Latitudinal change of zooplankton abundance coincided with increasing/decreasing tends of temperature and salinity. Two different zooplankton assemblages were identified by cluster analysis and these assemblages seem to be closely related to different water characteristics, such as the of PF and areas of cold water masses. CPR is considered to be an ideal tool for long term monitoring of surface zooplankton communities.

  10. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-12-01

    The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir) on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%), followed by Cladocera (16.45%) and Copepoda (12.53%). The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries.

  11. Oceanographic mechanisms that possibly explain dominance of neritic-tropical zooplankton species assemblages around the Islas Marías Archipelago, Mexico

    Directory of Open Access Journals (Sweden)

    Jaime Gómez-Gutiérrez

    2014-11-01

    Full Text Available The nearshore zooplankton species assemblage, identified per taxonomic groups (20 and per species for 12 selected groups, was analyzed from samples collected during November 2010 at four volcanic islands of the Islas Marías Archipelago (IMA, located 90-120 km offshore Nayarit, Mexico. From chlorophyll-a concentration and zooplankton biovolume perspective mesotrophic conditions prevailed in comparison with the Gulf of California during November. Crustaceans numerically dominated the zooplankton assemblage (92.3% [Copepoda (79.2%, Decapoda larvae (4.7%, Cladocera (3.7%, Mysidacea (2.7%, and Euphausiacea (2.0%]. The other 15 taxonomic groups (7.7% combined accounted each one less than 1.5% of the relative abundance. Species richness of selected taxa (~56%> included 259 taxa (121 identified to species, 117 to genus, and 21 not identified. Tropical species from neritic affinity clearly dominated zooplankton assemblage around IMA. Five tropical Copepoda species [Calanopia minor (Dana, Clausocalanus jobei Frost & Fleminger, Acrocalanus gibber Giesbrecht, Canthocalanus pauper (Giesbrecht, and Centropages furcatus (Dana], a cladoceran Pseudevadne tergestina (Claus, and a Mysidacea species (Mysidium reckettsi Harrison & Bowman dominated the zooplankton assemblage (accounting about 55% of total abundance of the identified species. Except C. furcatus, all these species are not abundant at oceanic regions of the central and northern Gulf of California. The similarity of multiple neritic and tropical species in the zooplankton assemblage from IMA and Cape Corrientes suggests strong coastal-insular plankton connectivity. Episodic current plumes associated with anomalous intense rivers discharge during rainy years, eddies generated by coastal upwelling event that move offshore, and northward regional oceanic circulation are the most likely mesoscale oceanographic processes that cause costal tropical zooplankton drift enhancing coastal-Archipelago species

  12. Zooplankton along the Tamil Nadu coast

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Saraswathy, M.

    Zooplankton abundance along two sectors at Cape Comorin and Tuticorin of Tamil Nadu Coast, southeast coast of India was studied. High biomass contributed by Ostracods, Salps, Chaetognaths etc., were observed along Tuticorin transect. In the Cape...

  13. Zooplankton Hydrodynamics

    DEFF Research Database (Denmark)

    Wadhwa, Navish

    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....... We studied how sensing modes and their respective ranges depend on body size. We investigated the physiological constraints on sense organs, together with the physics of signal generation, transmission, and reception. Our analysis revealed a hierarchy of sensing modes - with increasing size, a larger...

  14. Some crustacean zooplankton of Wular lake in Kashmir Himalaya ...

    African Journals Online (AJOL)

    In a taxonomic survey of crustacean zooplankton collected from Wular lake of Kashmir, a pictorial key was developed. Thirty-six (36) pictures of 25 species of crustacean zooplankton, out of which 21 represented 16 Cladocera taxa belonging to Chydoridae (Alona affinis, A. rectangula and A. monacantha, Chydorus ...

  15. Using occupancy modeling to compare traditional versus DNA metabarcoding methods for characterizing zooplankton biodiversity

    Science.gov (United States)

    DNA metabarcoding tools could increase our ability to detect changes in zooplankton communities and to detect invasive zooplankton taxa while they are still rare. Nonetheless, the use of DNA-metabarcoding for characterizing zooplankton biodiversity in the Great Lakes has not bee...

  16. Future marine zooplankton research - a perspective

    DEFF Research Database (Denmark)

    Bathmann, U.; Bundy, M.H.; Clarke, M.E.

    2001-01-01

    and existence of dominant zooplankton taxa, and (2) the control of biodiversity and biocomplexity, for example, in the tropical ocean where diversity is high. These recommendations come from an assemblage of chemical, physical and biological oceanographers with experience in major interdisciplinary studies...

  17. Zooplankton Structure and Potential Food Web Interactions in the Plankton of a Subtropical Chain-of-Lakes

    Directory of Open Access Journals (Sweden)

    Karl E. Havens

    2002-01-01

    Full Text Available This study evaluates the taxonomic and size structure of macro-zooplankton and its potential role in controlling phytoplankton in the Kissimmee Chain-of-Lakes, six shallow interconnected lakes in Florida, U.S. Macro-zooplankton species biomass and standard limnological attributes (temperature, pH, total phosphorus [TP], chlorophyll a [Chl a], and Secchi transparency were quantified on a bimonthly basis from April 1997 to February 1999. Concentrations of TP ranged from below 50 to over 150 μg l-1. Peak concentrations of particulate P coincided with maximal Chl a, and in one instance a high concentration of soluble reactive P followed. The cladoceran zooplankton was dominated by small species, including Eubosmina tubicen, Ceriodaphnia rigaudi, and Daphnia ambigua. The exotic daphnid, D. lumholtzii, periodically was abundant. The copepods were strongly dominated by Diaptomus dorsalis, a species previously shown to be highly resistant to fish predation. These results, and findings of controlled experiments on a nearby lake with a nearly identical zooplankton species complement, suggest that fish predation may be a major factor structuring the macro-zooplankton assemblage. Zooplankton biomass, on the other hand, may be affected by resource availability. There was a significant positive relationship between average biomass of macro-zooplankton and the average concentration of TP among the six lakes. No such relationship existed between zooplankton biomass and Chl a, suggesting that the predominant food web in these systems may be based on bacteria-plankton, as has been documented in nearby Lake Okeechobee. All of the zooplankton taxa encountered in the Kissimmee Chain-of-Lakes (except Mesocyclops edax are known bacteria grazers in Florida lakes. Phytoplankton biomass, measured as Chl a, was strongly associated with TP, both within and across lakes. Phytoplankton biomass was not associated with the biomass of zooplankton. These results, when

  18. Community response of zooplankton to oceanographic changes (2002-2012) in the central/southern upwelling system of Chile

    Science.gov (United States)

    Medellín-Mora, Johanna; Escribano, Ruben; Schneider, Wolfgang

    2016-03-01

    A 10-year time series (2002-2012) at Station 18 off central/southern Chile allowed us to study variations in zooplankton along with interannual variability and trends in oceanographic conditions. We used an automated analysis program (ZooImage) to assess changes in the mesozooplankton size structure and the composition of the taxa throughout the entire community. Oceanographic conditions changed over the decade: the water column became less stratified, more saline, and colder; the mixed layer deepened; and the oxygen minimum zone became shallower during the second half of the time series (2008-2012) in comparison with the first period (2002-2007). Both the size structure and composition of the zooplankton were significantly associated with oceanographic changes. Taxonomic and size diversity of the zooplankton community increased to the more recent period. For the second period, small sized copepods (1.5 mm) and medium size copepods (1-1.5 mm), whereas euphausiids, decapod larvae, appendicularian and ostracods increased their abundance during the second period. These findings indicated that the zooplankton community structure in this eastern boundary ecosystem was strongly influenced by variability of the upwelling process. Thus, climate-induced forcing of upwelling trends can alter the zooplankton community in this highly productive region with potential consequences for the ecosystem food web.

  19. NODC Standard Format Marine Zooplankton (F124) Data (1965-1983) (NODC Accession 0014196)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data type contains data from sampling and analysis of marine zooplankton. Information on zooplankton abundance, distribution and productivity derived from these...

  20. Distribución y abundancia del zooplancton del complejo lagunar Chacahua-La Pastoría, Oaxaca, México Distribution and abundance of zooplankton of the lagoon system Chacahua-La Pastoria, Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Benigno Pantaleón-López

    2005-06-01

    Full Text Available Se estudió la comunidad zooplánctica del sistema lagunar Chacahua-La Pastoría, antes de la apertura de la barra arenosa de Chacahua por la Secretaría de Marina. Se identificaron 26 grupos de zooplancton provenientes de 5 muestreos realizados en Mayo, Octubre, Diciembre de 1996 y Febrero y Junio de 1997, en el área investigada. En la Pastoría se registraron 25 grupos y en Chacahua 19; de los 26 grupos determinados 18 fueron comunes en ambas lagunas. El grupo más abundante fue el de las larvas de braquiuros que representaron el 35.7% del total del zooplancton, fueron seguidos por las larvas y huevos de peces con 22.74 y 15.26%, respectivamente. Los máximos valores promedio de abundancia se observaron durante el periodo de sequía, en las zonas aledañas al canal de intercomunicación de ambas lagunas, así como en las cercanías del canal de comunicación con el mar. En Chacahua se observaron las mayores densidades en Junio, 1997 y en La Pastoría en Diciembre, 1996. En general en la laguna La Pastoría la riqueza de grupos fue mayor. La composición de la comunidad zooplánctica está condicionada por la salinidad y la tasa de intercambio de agua entre la laguna y el mar.The zooplankton community of the lagoon system Chacahua-La Pastoría was studied before the opening of the sandy bar of Chacahua by the Secretaría de Marina. A total of 26 groups of zooplankton were identified at the lagoon complex Chacahua-La Pastoria made during five samplings in May, October and December, 1996 and February and June, 1997. In La Pastoria were recorded 25 groups and 19 in Chacahua. From 26 groups recorded, 18 were common in both lagoons. Braquiurid larvae were the most abundant group, and represent 35.7% of total zooplankton, followed by fish larvae and eggs with 22.74 and 15.26%, respectively. The maximum mean values of abundance were observed in the dry period in the adjacent zones to the channel of intercommunication of both lagoons, as well as in

  1. Sub-fossils of cladocerans in the surface sediment of 135 lakes as proxies for community structure of zooplankton, fish abundance and lake temperature

    DEFF Research Database (Denmark)

    Jeppesen, E.; Jensen, J. P.; Lauridsen, T. L.

    2003-01-01

    , which otherwise can be obtained only by long-term frequent contemporary sampling for several years. The contribution of Daphnia to the sum of Daphnia and Bosmina ephippia was negatively correlated with the abundance of fish expressed as catch per night in multi-mesh sized gill nets (CPUE). Yet, region...... to summer mean air temperature, and for Danish lakes also, albeit weakly, to fish CPUE but not to chlorophyll a. Apparently, temperature is the most important factor determining the ratio of parthenogenetic to ephippia producing specimens of Bosmina. We conclude that the sediment record of cladocerans...

  2. Diurnal variation of zooplankton in Malad creek, Bombay

    Digital Repository Service at National Institute of Oceanography (India)

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

    stock and total population were higher in night than in day collections. Abundance and diversity of zooplankton were directly correlated to the prevailing tide and pollution load. Copepods formed the predominant group followed by decapods, gastropods...

  3. Assessment of Zooplankton Community Structure of the Bahir Dar ...

    African Journals Online (AJOL)

    In general, species richness, evenness, and diversity increased as average abundance increased in the littoral zones of the lake. The dominant zooplankton were Bosmina longirostris, Daphnia lumholtzi, Thermodiaptomus galebi, Thermocyclops ethiopiensis, Diaphanosoma sarsi, Keratella sp., Brachionus sp., Filinia sp.

  4. Stratification of zooplankton in the northwestern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Paulinose, V.T.; Gopalakrishnan, T.C.; Nair, K.K.C.; Aravindakshan, P.N.

    Study on stratification of zooplankton in the north western Indian Ocean was carried out with special reference to its relative abundance and distribution. Samples were collected using multiple plankton net, during first cruise of ORV Sagar Kanya...

  5. Zooplankton and fisheries

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    is dominatEd. by herbivores. Zooplankton constitutes the main food item of several economic important animals. The pelagic fishes migrate in shoals to the feeding ground rich in food and hence zooplankton are used as indicators of rich potential fishing...

  6. Zooplankton production, composition and diversity in the coastal waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Padmavati, G.

    , siphonophores, chaetognaths and fish eggs were the other common taxa. Zooplankton population was never dominated by a single group. Swarms of copepods (Temora turbinata), cladocerans (Evadne tergestina), and pteropods (Creseis acicula) occurred in the nutrient...

  7. Spatial and temporal habitat partitioning by zooplankton in the Bornholm Basin (central Baltic Sea)

    DEFF Research Database (Denmark)

    Schultz, J.; Peck, M.A.; Barz, K.

    2012-01-01

    taxa (Bosmina coregoni maritima, Acartia spp., Pseudocalanus spp., Temora longicornis, Synchaeta spp.) contributed >10% to the zooplankton community composition. The appearance of cladocerans was mainly correlated with the phenology of thermocline development in the spring. The cladoceran B. coregoni...

  8. The crustacean zooplankton assemblage of a relatively pristine Utor ...

    African Journals Online (AJOL)

    The water quality and crustacean zooplankton of Utor River, a relatively pristine freshwater body in Edo State, Nigeria was investigated at four stations. The Utor River is slightly acidic, well oxygenated, oligotrophic and low in solids, conductivity, cations and heavy metals. A total of 380 individuals comprising eleven taxa ...

  9. Zooplankton assessment of Iyikpesu river Aragba- Orogun, Delta ...

    African Journals Online (AJOL)

    48.0 (39±9) mg CaCO3/L. All parameters were within permissible limits. Eighty– three (83) species of zooplankton belonging to five (5) taxonomic groups were identified. Rotifers contributed the highest number of taxa (36) followed by copepods ...

  10. spatial patterns of zooplankton distribution and abundance

    African Journals Online (AJOL)

    nb

    and preserved in specimen bottles containing. 4% formalin and ..... ingest small particles such as bacteria and ... degradation might have resulted in the .... Sneddon LU (2012) Clinical anesthesia and analgesia in fish. J. Exot. Pet. Med.

  11. Distribution of zooplankton populations within and adjacent to a thermal plume

    International Nuclear Information System (INIS)

    Evans, M.S.

    1981-01-01

    Zooplankton distributions in the 1-m stratum differed between ambient waters and the thermal plume of the Donald C. Cook Nuclear Power Plant. Zooplankton were most abundant in the warmest waters of the plume with the region of high densities extending over an approximate area of 0.2 to 0.3 km 2 . Water temperature was not a reliable indicator of alterations in zooplankton populations. Alterations were primarily due to upward vertical displacment of deep-living zooplankton. Large horizontal variability in zooplankton densities and use of conventional sampling procedures (vertically hauled nets, widely spaced stations) prevent traditionally designed monitoring programs from detecting such alterations. Zooplankton may experience indirect mortality losses in the plume if transfer of deep-living zooplankton to the surface layers makes them more visible to visual-feeding fish predators, and turbulences in the plume reduce zooplankters' ability to detect and avoid such predators. (auth)

  12. Marine zooplankton studies in Brazil: a brief evaluation and perspectives

    Directory of Open Access Journals (Sweden)

    Rubens M. Lopes

    2007-09-01

    Full Text Available Marine zooplankton research in Brazil has been primarily descriptive, with most studies focusing on community structure analysis and related issues. The composition and spatial distribution of several taxonomic groups are currently well known, although less-abundant and small-sized taxa as well as initial stages of almost all species have received little attention. Some numerically important taxa such as heterotrophic protists, ctenophores, acoel turbellarians and ostracods remain virtually unstudied. Large sectors of the continental shelf have not been sampled in detail, particularly those areas influenced by the North Brazil Current (5ºN-15ºS. Zooplankton abundance and biomass in offshore waters have seldom been quantified, and information on the distribution and vertical migration of meso- and bathypelagic species are lacking. Additional faunistic assessments must target those less-studied taxa and geographical locations. However, priority in ecological studies should be given to process-oriented investigations aimed at understanding the mechanisms controlling zooplankton distribution, trophic interactions within pelagic food webs and production cycles in relation to the physical environment. An effort should be made to incorporate state-of-the-art sampling technology and analytical methods into future research projects.As pesquisas sobre o zooplâncton marinho no Brasil têm sido primariamente descritivas, com a maioria dos estudos enfocando a análise da estrutura da comunidade e assuntos relacionados. A composição e a distribuição espacial de muitos grupos taxonômicos encontram-se bem estudadas, embora os táxons menos abundantes e de menores dimensões, assimcomo os estágios iniciais do ciclo de vida da maioria das espécies, tenham recebido pouca atenção. Alguns táxons numericamenteimportantes encontram-se pouco estudados, como no caso dos protistas heterotróficos, ctenóforos, turbelários acelos e ostrácodes. Amplos

  13. Effects of nutrients and zooplankton on the phytoplankton community structure in Marudu Bay

    Science.gov (United States)

    Tan, Kar Soon; Ransangan, Julian

    2017-07-01

    Current study was carried out to provide a better understanding on spatial and temporal variations in the phytoplankton community structure in Marudu Bay, an important nursery ground for fishery resources within the Tun Mustapha Marine Park and Coral Triangle Initiative, and their relationship with environmental variables. Samplings were conducted monthly from April 2014 to April 2015 in Marudu Bay, Malaysia. Water samples were collected for nutrients analysis, zooplankton and phytoplankton counting. Moreover, the in situ environmental parameters were also examined. The field study showed a total of forty seven phytoplankton genera, representative of 33 families were identified. The nutrient concentrations in Marudu Bay was low (mesotrophic) throughout the year, where the phytoplankton community was often dominated by Chaetoceros spp. and Bacteriastrum spp. In general, increase in nitrate concentration triggered the bloom of centric diatom, Chaetoceros spp. and Bacteriastrum spp. in Marudu Bay. However, the bloom of these phytoplankton taxa did not occur in the presence of high ammonia concentration. In addition, high abundance of zooplankton also a limiting factor of the phytoplankton blooms particularly at end of southwest monsoon. High silica concentration promoted the growth of pennate diatoms, Proboscia spp. and Thallassionema spp., but the depletion of silica quickly terminated the bloom. Interestingly, our study showed that Chaetoceros spp., tolerated silica depletion condition, but the average cell size of this taxon reduced significantly. In summary, the phytoplankton community structure in mesotrophic environment is more sensitive to the changes in zooplankton abundance, nutrient concentration and its ratio than that in nutrient rich environments. This study also recommends that bivalve farming at industrial scale is not recommended in Marudu Bay because it potentially depletes the primary productivity hence jeopardizing the availability of live food for

  14. Ocean acidification alters zooplankton communities and increases top-down pressure of a cubozoan predator.

    Science.gov (United States)

    Hammill, Edd; Johnson, Ellery; Atwood, Trisha B; Harianto, Januar; Hinchliffe, Charles; Calosi, Piero; Byrne, Maria

    2018-01-01

    The composition of local ecological communities is determined by the members of the regional community that are able to survive the abiotic and biotic conditions of a local ecosystem. Anthropogenic activities since the industrial revolution have increased atmospheric CO 2 concentrations, which have in turn decreased ocean pH and altered carbonate ion concentrations: so called ocean acidification (OA). Single-species experiments have shown how OA can dramatically affect zooplankton development, physiology and skeletal mineralization status, potentially reducing their defensive function and altering their predatory and antipredatory behaviors. This means that increased OA may indirectly alter the biotic conditions by modifying trophic interactions. We investigated how OA affects the impact of a cubozoan predator on their zooplankton prey, predominantly Copepoda, Pleocyemata, Dendrobranchiata, and Amphipoda. Experimental conditions were set at either current (pCO 2 370 μatm) or end-of-the-century OA (pCO 2 1,100 μatm) scenarios, crossed in an orthogonal experimental design with the presence/absence of the cubozoan predator Carybdea rastoni. The combined effects of exposure to OA and predation by C. rastoni caused greater shifts in community structure, and greater reductions in the abundance of key taxa than would be predicted from combining the effect of each stressor in isolation. Specifically, we show that in the combined presence of OA and a cubozoan predator, populations of the most abundant member of the zooplankton community (calanoid copepods) were reduced 27% more than it would be predicted based on the effects of these stressors in isolation, suggesting that OA increases the susceptibility of plankton to predation. Our results indicate that the ecological consequences of OA may be greater than predicted from single-species experiments, and highlight the need to understand future marine global change from a community perspective. © 2017 John Wiley & Sons

  15. 137Cs concentration in zooplankton and its relation to taxonomic composition in the western North Pacific Ocean

    International Nuclear Information System (INIS)

    Kaeriyama, Hideki; Watabe, Teruhisa; Kusakabe, Masashi

    2008-01-01

    To study the role of zooplankton in the transport of 137 Cs in the ocean, zooplankton samples were collected in October 2005 and June 2006 in the western North Pacific Ocean. The peak zooplankton biomass was observed in the surface layer, and gelatinous plankton was more abundant in October 2005 than in June 2006 reflecting exchange of water masses. The concentrations of 137 Cs in zooplankton varied from 11 to 24 mBq kg wet -1 and were higher in October 2005 than in June 2006. The elevated abundance of gelatinous zooplankton probably led to higher concentration of 137 Cs in zooplankton in October 2005. Annual export fluxes of 137 Cs by ontogenetic vertical migrant copepods were estimated to be 0.8 and 0.6 mBq m -2 year -1 at 200 and 1000 m depths, respectively; this suggested that transport of 137 Cs by zooplankton may be no trivial pathway

  16. The impact of fish predation and cyanobacteria on zooplankton size structure in 96 subtropical lakes.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available Zooplankton are relatively small in size in the subtropical regions. This characteristic has been attributed to intense predation pressure, high nutrient loading and cyanobacterial biomass. To provide further information on the effect of predation and cyanobacteria on zooplankton size structure, we analyzed data from 96 shallow aquaculture lakes along the Yangtze River. Contrary to former studies, both principal components analysis and multiple regression analysis showed that the mean zooplankton size was positively related to fish yield. The studied lakes were grouped into three types, namely, natural fishing lakes with low nutrient loading (Type1, planktivorous fish-dominated lakes (Type 2, and eutrophic lakes with high cyanobacterial biomass (Type 3. A marked difference in zooplankton size structure was found among these groups. The greatest mean zooplankton size was observed in Type 2 lakes, but zooplankton density was the lowest. Zooplankton abundance was highest in Type 3 lakes and increased with increasing cyanobacterial biomass. Zooplankton mean size was negatively correlated with cyanobacterial biomass. No obvious trends were found in Type 1 lakes. These results were reflected by the normalized biomass size spectrum, which showed a unimodal shape with a peak at medium sizes in Type 2 lakes and a peak at small sizes in Type 3 lakes. These results indicated a relative increase in medium-sized and small-sized species in Types 2 and 3 lakes, respectively. Our results suggested that fish predation might have a negative effect on zooplankton abundance but a positive effect on zooplankton size structure. High cyanobacterial biomass most likely caused a decline in the zooplankton size and encouraged the proliferation of small zooplankton. We suggest that both planktivorous fish and cyanobacteria have substantial effects on the shaping of zooplankton community, particularly in the lakes in the eastern plain along the Yangtze River where

  17. The effect of salinity levels on the structure of zooplankton communities

    Directory of Open Access Journals (Sweden)

    Paturej Ewa

    2015-01-01

    Full Text Available The objective of this study was to determine the qualitative and quantitative structure of zooplankton communities in the Vistula Lagoon and to establish whether zooplankton abundance and biodiversity are affected by salinity levels. Samples for biological analyses were collected in the summer (June-September of 2007-2011 at eleven sampling sites. Statistical analysis revealed a significant correlation between salinity levels and the number of species (r= -0.2020, abundance (r= 0.1967 and biomass (r= 0.3139 of zooplankton. No significant correlations were found between salinity and the biodiversity of zooplankton. The results of the study suggest that salinity affects the abundance and structure, but not the diversity of zooplankton communities in the Vistula Lagoon.

  18. High mortality of Red Sea zooplankton under ambient solar radiation.

    Science.gov (United States)

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  19. High mortality of Red Sea zooplankton under ambient solar radiation.

    Directory of Open Access Journals (Sweden)

    Ali M Al-Aidaroos

    Full Text Available High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation. The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM 18.4±5.8% h(-1, five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM 12±5.6 h(-1% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  20. Power-plant-related estuarine zooplankton studies

    International Nuclear Information System (INIS)

    Sage, L.E.; Olson, M.M.

    1981-01-01

    In-plant studies examining the effects of entrainment on zooplankton and field studies examining zooplankton abundance, composition, and distribution in the Chesapeake Bay in the vicinity of Calvert Cliffs Nuclear Power Plant have been conducted from 1974 to the present. The evolution of these studies, with particular emphasis on design and statistical treatment, is discussed. Entrainment study designs evolved from discrete sampling episodes at 4-h intervals over 24 h to a time-series sampling design in which sampling took place every 30 min over 24 and 48-h periods. The near-field study design and samping methods have included replicated net tows, using 0.5-m nets, and replicated and nonreplicated pumped sampling, using a high-speed centrifugal pump. 16 refs

  1. Phytoplanktons and zooplanktons diversity in karachi coastal seawater under high and low tide during winter monsoon

    International Nuclear Information System (INIS)

    Yaqoob, N.; Mashiatullah, A.; Sher, N.; Javed, T.; Ghaffar, A.

    2013-01-01

    This paper represents the population density of phytoplanktons and zooplanktons recorded during the marine environmental studies at Karachi coast in the month of February 2011. Samples were collected by towing net, preserved and quantification and identification was carried out under light microscope. Twenty-three phytoplanktons species and nine zooplankton groups were recorded in the seawater from the sampling area of 10 square kilometers. Coscinodiscus and Copepods were dominant in the population of phytoplankton and zooplankton, respectively. Phytoplankton population density increased while zooplankton abundance decreased offshore from the coastline in the open sea. (author)

  2. Population dynamics of Chaoborus flavicans and Daphnia spp.: effects on a zooplankton community in a volcanic eutrophic lake with naturally high metal concentrations (L. Monticchio Grande, Southern Italy

    Directory of Open Access Journals (Sweden)

    Letizia GARIBALDI

    2009-02-01

    Full Text Available The response of Daphnia populations to invertebrate predators involves morphological or behavioural changes. Few studies suggest that contaminant aqueous metals, like Cu or Ni at environmentally relevant concentrations, interfere with invertebrate chemical communication systems, such as that which operates between Daphnia and Chaoborus. The objective of our study was to determine if this interference could be also observed in lakes naturally rich in dissolved metals, such as volcanic lake (Lago Grande di Monticchio. This study aimed to assess if natural dissolved metals (e.g., Fe, Mn and Sr could impair the ability of Daphnia pulex and D. galeata × hyalina × cucullata 'complex' populations to respond to Chaoborus kairomones by producing morphological defenses against potential predation, and to understand how Chaoborus predation might affect zooplankton community composition and overall zooplankton density. The predator impact did not result in: i any morphological changes; ii any apparent shift in body size pattern of the prey population; iii any shift in life history traits. Chaoborus accounted for high mortality rates in Cladocera and strongly reduced the chance of individuals to reach maturity. Moreover, highly significant negative correlations between abundance of dominant taxa of zooplankton and C. flavicans were found. The last larval instars of C. flavicans seem to reduce the number of crustaceans, particularly cladocerans and copepod adults and could play an important role in structuring zooplankton communities. Our results suggest that metal inhibition of defence strategies induction probably occurs along the signal transduction pathway in Lake Grande di Monticchio. Impairment of chemosensory response to predatory chemical cues may have widespread ecological consequences in aquatic systems. Chaoborus predation effects can greatly affect both zooplankton biomass and community composition, impact interactions at lower trophic levels

  3. Abundância de liquidez e crise financeira em Roma: questões jurídicas e econômicas em torno das taxas de juros na época de Augusto e de Tibério Abundance of currency and financial crisis in Rome: legal and economic issues around interest rates at the time of Augustus and Tiberius

    Directory of Open Access Journals (Sweden)

    Deivid Valério Gaia

    2009-01-01

    Full Text Available Após ter vencido Antônio e Cleópatra na Batalha do Ácio em 31 a.C., Otaviano levou o tesouro dos reis do Egito a Roma, criando uma abundância de riquezas que contribui, consideravelmente, para estabilizar as finanças romanas, públicas e privadas, e que provocou a alta do preço da terra e a baixa das taxas de juros. Durante o Principado de Augusto, a economia romana conheceu um período de equilíbrio financeiro. No entanto, este equilíbrio foi rompido no início da década de 30 d.C. quando, de acordo com os relatos de Tácito, Suetônio e Dion Cássio, eclodiu a primeira crise financeira do Império Romano, crise de inopia nummorum (insuficiência de moedas em circulação, no Principado de Tibério. Partindo do estudo dos autores citados e de uma perspectiva comparativa com outras crises financeiras no Império romano, o meu objetivo neste artigo é de apresentar: na primeira parte, algumas considerações sobre as taxas de juros do fim da República ao Principado; na segunda parte, um quadro geral das questões dos empréstimos de dinheiro e das taxas de juros na época de Augusto; para, na terceira parte, propor uma nova leitura da crise de 33 d.C.After defeating Antony and Cleopatra at Actium in 31 BC, Octovian brought the treasury of Egypt to Rome thus providing an abundance of wealth wich contributed to stabilize both public and private finances. The value of land increased and interest rates fell. During the Augustan Principate, Roman economy went through a period of financial equilibrium. However, this balance was broken in the early 30's AD under Tiberius' Principate when, according to Tacitus, Suetonius and Dion Cassius, the first inopia nummorum (lack of liquidity crisis of the Roman Empire came about. Based on the accounts cited above and a comparative perspective with other financial crises in the Roman Empire, this paper examines issues concerning interest rates from the end of the Republic to the Principate, it presents

  4. Efectos del herbicida Paraquat sobre el zooplancton Effects of Paraquat herbicide on zooplankton

    Directory of Open Access Journals (Sweden)

    Ana María Gagneten

    2002-09-01

    Full Text Available The effects of 0.1; 0.2; 0.4 and 0.8 mlPQ/L were analized on a zooplankton community, to determine the most sensitive species and to analize the occurence of physical abnormalities. A total of 40 taxa were determined. Paraquat affected significantly the zooplankton density but not the species richness. A progressive state of deformation of these organisms was also observed. Paraquat showed to be highly toxic for the zooplankton, so this herbicide should be strictly regulated in aquatic and terrestrial ecosystems.

  5. Spatial variation of the zooplankton community in the western tropical Pacific Ocean during the summer of 2014

    Science.gov (United States)

    Yang, Guang; Li, Chaolun; Wang, Yanqing; Wang, Xiaocheng; Dai, Luping; Tao, Zhencheng; Ji, Peng

    2017-03-01

    Knowledge of the zooplankton community in the western tropical Pacific Ocean is poor compared to that of the communities in the central and eastern Pacific Ocean. The zooplankton composition, abundance, biomass and community structure in the western Pacific Ocean were studied based on data collected during a synoptic cruise (August-September 2014). Four zooplankton communities were determined via cluster analysis, and these four clusters were mainly spatially related to four different currents: the Luzon Current (LC), Subtropical Countercurrent (STCC), North Equatorial Current (NEC) and North Equatorial Countercurrent (NECC). The estimated mean abundance and biomass of the zooplankton for the whole surveyed area were 146.7±178.1 ind/m3 and 36.9±40.3 mg/m3, respectively. The zooplankton abundance was dominated by small copepods, such as Clausocalanus furcatus, C. pergens, Oncaea mediterranea and Oithona plumifera. The zooplankton abundance and biomass values were lowest in the STCC region and highest in the NECC region. BEST analysis based on surface environmental factors showed that chlorophyll a (chl a), pH, temperature and salinity were the environmental variables that best explained the distribution pattern of the zooplankton community (pw=0.372). The zooplankton abundance was higher south of the salinity front at 16°N, in accordance with the relatively higher nutrient and chl a levels. Maximum zooplankton biomass was found in regions on the periphery of the cyclonic Mindanao Eddy (ME) and anticyclonic Halmahera Eddy (HE).

  6. ZOOPLANKTON DIVERSITY AND ITS RELATIONSHIP WITH PHYSICO-CHEMICAL PARAMETERS IN MANI RESERVOIR OF WESTERN GHATS, REGION, HOSANAGAR TALUK, SHIVAMOGA DISTRICT KARNATAKA, INDIA

    Directory of Open Access Journals (Sweden)

    D. N. Veerendra

    2012-01-01

    Full Text Available Studies on relationship between zooplankton abundance and water quality parameter in Mani reservoir were made between January 2008 and December 2008. In the current investigation, impact of different physico-chemical parameters on zooplankton population was found. Ten genera of zooplankton were identified. The relationship between zooplankton and water quality parameters was varied from place to place depending upon the condition of the reservoir water.

  7. Zooplankton structure and vertical migration: Using acoustics and biomass to compare stratified and mixed fjord systems

    Science.gov (United States)

    Díaz-Astudillo, Macarena; Cáceres, Mario A.; Landaeta, Mauricio F.

    2017-09-01

    The patterns of abundance, composition, biomass and vertical migration of zooplankton in short-time scales (ADCP device mounted on the hull of a ship were used to obtain vertical profiles of current velocity data and intensity of the backscattered acoustic signal, which was used to study the migratory strategies and to relate the echo intensity with zooplankton biomass. Repeated vertical profiles of temperature, salinity and density were obtained with a CTD instrument to describe the density patterns during both experiments. Zooplankton were sampled every 3 h using a Bongo net to determine abundance, composition and biomass. Migrations were diel in the stratified station, semi-diel in the mixed station, and controlled by light in both locations, with large and significant differences in zooplankton abundance and biomass between day and night samples. No migration pattern associated with the effect of tides was found. The depth of maximum backscatter strength showed differences of approximately 30 m between stations and was deeper in the mixed station. The relation between mean volume backscattering strength (dB) computed from echo intensity and log10 of total dry weight (mg m-3) of zooplankton biomass was moderate but significant in both locations. Biomass estimated from biological samples was higher in the mixed station and determined by euphausiids. Copepods were the most abundant group in both stations. Acoustic methods were a useful technique to understand the detailed patterns of migratory strategies of zooplankton and to help estimate zooplankton biomass and abundance in the inner waters of southern Chile.

  8. Temporal and spatial variability of zooplankton on the Faroe shelf in spring 1997-2016

    Science.gov (United States)

    Jacobsen, Sólvá; Gaard, Eilif; Larsen, Karin Margretha Húsgarð; Eliasen, Sólvá Káradóttir; Hátún, Hjálmar

    2018-01-01

    Zooplankton availability during spring and summer determines the growth and survival of first-feeding fish larvae, and thus impacts the recruitment to both fish prey species and commercial fish stocks. On the Faroe shelf, however, the relative importance of oceanic versus neritic zooplankton species has hitherto not been well understood. In this study, spatio-temporal variability in zooplankton community structure and size spectra on the Faroe shelf is investigated using observations from late April during the period 1997-2016. The main objective was to explore which environmental variables influence the zooplankton community structure in early spring. The zooplankton community in the permanently well mixed central shelf inside the tidal front consists of a mixture of neritic, cosmopolitan and oceanic species. In this region, redundancy analyses showed that chlorophyll concentration had a positive effect on abundance of neritic copepods and meroplankton as well as all zooplankton abundance variability of these species shows increased production around 2000 and 2008-2009. The highest zooplankton abundance, mainly consisting of Calanus finmarchicus, is however observed off-shore from the tidal front, especially on the western side of the Faroe Plateau. A shift in C. finmarchicus phenology occurred around 2007, resulting in earlier reproduction of this species, and this variability could not be explained by the employed regional environmental parameters. Our results indicate that the Faroe shelf biological production is more dependent on the local primary production and neritic zooplankton species than on the large oceanic C. finmarchicus stock.

  9. AFSC/RACE/EcoFOCI - Zooplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska, 1987 – Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data are abundance by taxanomic group (to species where possible), stage, size and sex. Zooplankton sorting is performed at The Polish Plankton Sorting...

  10. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kürten, Benjamin

    2015-11-10

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one approach to elucidating pelagic food web structures and diet assimilation Integrating the combined effects of ecological processes and hydrography, ecohydrographic features often translate into geographic patterns in δ13C and δ15N values at the base of food webs. This is due, for example, to divergent 15N abundances in source end-members (deep water sources: high δ15N, diazotrophs: low δ15N). Such patterns in the spatial distributions of stable isotope values were coined isoscapes. Empirical data of atmospheric, oceanographic, and biological processes, which drive the ecohydrographic gradients of the oligotrophic Red Sea, are under-explored and some rather anticipated than proven. Specifically, five processes underpin Red Sea gradients: a) monsoon-related intrusions of nutrient-rich Indian Ocean water; b) basin scale thermohaline circulation; c) mesoscale eddy activity that causes up-welling of deep water nutrients into the upper layer; d) the biological fixation of atmospheric nitrogen (N2) by diazotrophs; and e) the deposition of aerosol-derived N. This study assessed relationships between environmental samples (nutrients, chlorophyll a), oceanographic data (temperature, salinity, current velocity [ADCP]), particulate organic matter (POM), and net-phytoplankton, with the δ13C and δ15N values of zooplankton collected in spring 2012 from 16°28’ to 26°57’N along the central axis of the Red Sea. The δ15N of bulk POM and most zooplankton taxa increased from North (Duba) to South (Farasan). The potential contribution of deep water nutrient-fueled phytoplankton, POM, and diazotrophs varied among sites. Estimates suggested higher diazotroph contributions in the North, a greater contribution of POM in the South

  11. Zooplankton ecology in the Mandovi-Zuari estuarine system of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Padmavati, G.; Goswami, S.C.

    .6%). Invertebrate larvae, luciferied shrimps, cladocerans and chaetognaths were the other common zooplankton groups. Distribution and abundance of majority of constituent groups and species were influenced by various hydrographical characteristics of the environment....

  12. Spatial zonation of zooplankton in the northwestern Arabian Sea: A multivariate approach

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.

    Latitudinal variation in abundance, diversity, dominance pattern and zonation of the major groups of zooplankton was studied n the coastal waters of northwestern Arabian Sea, between 25°44' N and 10°44' N. Maxwell Boltzmann Statistic...

  13. The effect of some environmental factors on zooplankton community ...

    African Journals Online (AJOL)

    The zooplankton of Lake Qarun was studied January–December 2003. A total of 26 species was recorded, amongst which protozoa, primarily ciliophora, were most abundant (79% of the species total), followed by rotifera (13%) and copepoda (8%). The average density ranged from 965–1 452 l–1. The highest density (2 ...

  14. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria

    Directory of Open Access Journals (Sweden)

    Moshood K Mustapha

    2009-12-01

    Full Text Available The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%, followed by Cladocera (16.45% and Copepoda (12.53%. The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries. Rev. Biol. Trop. 57 (4: 1027-1047. Epub 2009 December 01.La influencia de las propiedades fisicoquímicas del Reservorio Oyun, Offa, Nigeria (un embalse tropical somero sobre la composición y abundancia del zooplancton fue investigada en tres estaciones entre enero de 2002 y diciembre de 2003. La diversidad no resultó muy alta con tres grupos de zooplancton: Rotifera con ocho géneros, y Cladocera y Copepoda con tres géneros cada uno. Rotifera dominó (71.02%, seguido de Cladocera (16.45% y Copepoda (12.53%. El zooplancton fue más común durante la temporada de lluvias, y hubo variaciones en su composición y abundancia a lo largo del embalse. Factores tales como la temperatura, los nutrientes, la disponibilidad de alimentos, la forma y la hidrodinámica del embalse, así como las estrategias reproductivas de los organismos, influyen fuertemente en la composición genérica y la densidad poblacional del zooplancton. La

  15. Predictive models for monitoring and analysis of the total zooplankton

    Directory of Open Access Journals (Sweden)

    Obradović Milica

    2014-01-01

    Full Text Available In recent years, modeling and prediction of total zooplankton abundance have been performed by various tools and techniques, among which data mining tools have been less frequent. The purpose of this paper is to automatically determine the dependency degree and the influence of physical, chemical and biological parameters on the total zooplankton abundance, through design of the specific data mining models. For this purpose, the analysis of key influencers was used. The analysis is based on the data obtained from the SeLaR information system - specifically, the data from the two reservoirs (Gruža and Grošnica with different morphometric characteristics and trophic state. The data is transformed into optimal structure for data analysis, upon which, data mining model based on the Naïve Bayes algorithm is constructed. The results of the analysis imply that in both reservoirs, parameters of groups and species of zooplankton have the greatest influence on the total zooplankton abundance. If these inputs (group and zooplankton species are left out, differences in the impact of physical, chemical and other biological parameters in dependences of reservoirs can be noted. In the Grošnica reservoir, analysis showed that the temporal dimension (months, nitrates, water temperature, chemical oxygen demand, chlorophyll and chlorides, had the key influence with strong relative impact. In the Gruža reservoir, key influence parameters for total zooplankton are: spatial dimension (location, water temperature and physiological groups of bacteria. The results show that the presented data mining model is usable on any kind of aquatic ecosystem and can also serve for the detection of inputs which could be the basis for the future analysis and modeling.

  16. Characterisation of large zooplankton sampled with two different gears during midwinter in Rijpfjorden, Svalbard

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    Błachowiak-Samołyk Katarzyna

    2017-12-01

    Full Text Available During a midwinter cruise north of 80°N to Rijpfjorden, Svalbard, the composition and vertical distribution of the zooplankton community were studied using two different samplers 1 a vertically hauled multiple plankton sampler (MPS; mouth area 0.25 m2, mesh size 200 μm and 2 a horizontally towed Methot Isaacs Kidd trawl (MIK; mouth area 3.14 m2, mesh size 1500 μm. Our results revealed substantially higher species diversity (49 taxa than if a single sampler (MPS: 38 taxa, MIK: 28 had been used. The youngest stage present (CIII of Calanus spp. (including C. finmarchicus and C. glacialis was sampled exclusively by the MPS, and the frequency of CIV copepodites in MPS was double that than in MIK samples. In contrast, catches of the CV-CVI copepodites of Calanus spp. were substantially higher in the MIK samples (3-fold and 5-fold higher for adult males and females, respectively. The MIK sampling clearly showed that the highest abundances of all three Thysanoessa spp. were in the upper layers, although there was a tendency for the larger-sized euphausiids to occur deeper. Consistent patterns for the vertical distributions of the large zooplankters (e.g. ctenophores, euphausiids collected by the MPS and MIK samplers provided more complete data on their abundances and sizes than obtained by the single net. Possible mechanisms contributing to the observed patterns of distribution, e.g. high abundances of both Calanus spp. and their predators (ctenophores and chaetognaths in the upper water layers during midwinter are discussed.

  17. Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

    KAUST Repository

    Coello-Camba, A.; Llabré s, M.; Duarte, Carlos M.; Agusti, Susana

    2017-01-01

    Warming over Antarctica is leading to changes in the zooplankton communities inhabiting the Southern Ocean. It has been observed that zooplankton not only regulates phytoplankton through grazing, but also through the recycling of nutrients that are essential for phytoplankton growth. In this way, the effects of warming on zooplankton populations will change the amount or proportion at which recycled nutrients are restored. To estimate how the recycled nutrients released by zooplankton populations, dominated by krill (Euphausia superba), amphipods or copepods, affect the phytoplankton uptake and communities, we performed four incubation experiments: two close to the Antarctic Peninsula and two at the Southern Atlantic Ocean. Our results showed a stimulating effect of the addition of metabolites on ammonia removal rates and on the net growth of phytoplankton communities, with different responses amongst the different phytoplankton groups. According to our results, phytoplankton net growth and community composition may be altered if this relevant source of nutrients is lost due to projected changes in the abundance or distribution of these zooplankton populations.

  18. Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

    KAUST Repository

    Coello-Camba, A.

    2017-04-24

    Warming over Antarctica is leading to changes in the zooplankton communities inhabiting the Southern Ocean. It has been observed that zooplankton not only regulates phytoplankton through grazing, but also through the recycling of nutrients that are essential for phytoplankton growth. In this way, the effects of warming on zooplankton populations will change the amount or proportion at which recycled nutrients are restored. To estimate how the recycled nutrients released by zooplankton populations, dominated by krill (Euphausia superba), amphipods or copepods, affect the phytoplankton uptake and communities, we performed four incubation experiments: two close to the Antarctic Peninsula and two at the Southern Atlantic Ocean. Our results showed a stimulating effect of the addition of metabolites on ammonia removal rates and on the net growth of phytoplankton communities, with different responses amongst the different phytoplankton groups. According to our results, phytoplankton net growth and community composition may be altered if this relevant source of nutrients is lost due to projected changes in the abundance or distribution of these zooplankton populations.

  19. Abundant plankton-sized microplastic particles in shelf waters of the northern Gulf of Mexico.

    Science.gov (United States)

    Di Mauro, Rosana; Kupchik, Matthew J; Benfield, Mark C

    2017-11-01

    Accumulation of marine debris is a global problem that affects the oceans on multiple scales. The majority of floating marine debris is composed of microplastics: plastic particles up to 5 mm in diameter. With similar sizes and appearances to natural food items, these small fragments pose potential risks to many marine organisms including zooplankton and zooplanktivores. Semi-enclosed seas are reported to have high concentrations of microplastics, however, the distribution and concentration of microplastics in one such system, the Gulf of Mexico, remains unknown. Our study documented and characterized microplastics in continental shelf waters off the Louisiana coast in the northern Gulf of Mexico, using bongo nets, neuston nets, and Niskin bottles. Additionally, we compared the size distributions of microplastics and zooplankton collected using the nets. Plastics were manually sorted from the samples, documented, and measured using digital microscopy. Confirmation of putative plastics was carried out by hydrofluoric acid digestion and a subsample was analyzed using FTIR microscopy. Estimated concentrations of microplastics collected on the inner continental shelf during this study are among the highest reported globally. Total microplastic concentrations ranged from 4.8 to 8.2 particles m -3 and 5.0-18.4 particles m -3 for the bongo and neuston samples, respectively. Niskin bottles collected smaller plastic particles than the nets and indicated total microplastic concentrations (primarily fibers) from 6.0E4 - 15.7E4 particles m -3 . Microplastic concentrations were greater than the abundances of all but four of the five most abundant taxa from bongo nets and were not statistically different from the abundances of any of the most numerous taxa from neuston nets. Sizes of microplastics and zooplankton partially or completely overlapped, suggesting the potential for confusion with natural prey. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Abundance, distribution and diversity of gelatinous predators along the northern Mid-Atlantic Ridge: A comparison of different sampling methodologies.

    Directory of Open Access Journals (Sweden)

    Aino Hosia

    Full Text Available The diversity and distribution of gelatinous zooplankton were investigated along the northern Mid-Atlantic Ridge (MAR from June to August 2004.Here, we present results from macrozooplankton trawl sampling, as well as comparisons made between five different methodologies that were employed during the MAR-ECO survey. In total, 16 species of hydromedusae, 31 species of siphonophores and four species of scyphozoans were identified to species level from macrozooplankton trawl samples. Additional taxa were identified to higher taxonomic levels and a single ctenophore genus was observed. Samples were collected at 17 stations along the MAR between the Azores and Iceland. A divergence in the species assemblages was observed at the southern limit of the Subpolar Frontal Zone. The catch composition of gelatinous zooplankton is compared between different sampling methodologies including: a macrozooplankton trawl; a Multinet; a ringnet attached to bottom trawl; and optical platforms (Underwater Video Profiler (UVP & Remotely Operated Vehicle (ROV. Different sampling methodologies are shown to exhibit selectivity towards different groups of gelatinous zooplankton. Only ~21% of taxa caught during the survey were caught by both the macrozooplankton trawl and the Multinet when deployed at the same station. The estimates of gelatinous zooplankton abundance calculated using these two gear types also varied widely (1.4 ± 0.9 individuals 1000 m-3 estimated by the macrozooplankton trawl vs. 468.3 ± 315.4 individuals 1000 m-3 estimated by the Multinet (mean ± s.d. when used at the same stations (n = 6. While it appears that traditional net sampling can generate useful data on pelagic cnidarians, comparisons with results from the optical platforms suggest that ctenophore diversity and abundance are consistently underestimated, particularly when net sampling is conducted in combination with formalin fixation. The results emphasise the importance of considering

  1. Abundance, distribution and diversity of gelatinous predators along the northern Mid-Atlantic Ridge: A comparison of different sampling methodologies

    Science.gov (United States)

    Falkenhaug, Tone; Baxter, Emily J.

    2017-01-01

    The diversity and distribution of gelatinous zooplankton were investigated along the northern Mid-Atlantic Ridge (MAR) from June to August 2004.Here, we present results from macrozooplankton trawl sampling, as well as comparisons made between five different methodologies that were employed during the MAR-ECO survey. In total, 16 species of hydromedusae, 31 species of siphonophores and four species of scyphozoans were identified to species level from macrozooplankton trawl samples. Additional taxa were identified to higher taxonomic levels and a single ctenophore genus was observed. Samples were collected at 17 stations along the MAR between the Azores and Iceland. A divergence in the species assemblages was observed at the southern limit of the Subpolar Frontal Zone. The catch composition of gelatinous zooplankton is compared between different sampling methodologies including: a macrozooplankton trawl; a Multinet; a ringnet attached to bottom trawl; and optical platforms (Underwater Video Profiler (UVP) & Remotely Operated Vehicle (ROV)). Different sampling methodologies are shown to exhibit selectivity towards different groups of gelatinous zooplankton. Only ~21% of taxa caught during the survey were caught by both the macrozooplankton trawl and the Multinet when deployed at the same station. The estimates of gelatinous zooplankton abundance calculated using these two gear types also varied widely (1.4 ± 0.9 individuals 1000 m-3 estimated by the macrozooplankton trawl vs. 468.3 ± 315.4 individuals 1000 m-3 estimated by the Multinet (mean ± s.d.) when used at the same stations (n = 6). While it appears that traditional net sampling can generate useful data on pelagic cnidarians, comparisons with results from the optical platforms suggest that ctenophore diversity and abundance are consistently underestimated, particularly when net sampling is conducted in combination with formalin fixation. The results emphasise the importance of considering sampling methodology

  2. Abundance, distribution and diversity of gelatinous predators along the northern Mid-Atlantic Ridge: A comparison of different sampling methodologies.

    Science.gov (United States)

    Hosia, Aino; Falkenhaug, Tone; Baxter, Emily J; Pagès, Francesc

    2017-01-01

    The diversity and distribution of gelatinous zooplankton were investigated along the northern Mid-Atlantic Ridge (MAR) from June to August 2004.Here, we present results from macrozooplankton trawl sampling, as well as comparisons made between five different methodologies that were employed during the MAR-ECO survey. In total, 16 species of hydromedusae, 31 species of siphonophores and four species of scyphozoans were identified to species level from macrozooplankton trawl samples. Additional taxa were identified to higher taxonomic levels and a single ctenophore genus was observed. Samples were collected at 17 stations along the MAR between the Azores and Iceland. A divergence in the species assemblages was observed at the southern limit of the Subpolar Frontal Zone. The catch composition of gelatinous zooplankton is compared between different sampling methodologies including: a macrozooplankton trawl; a Multinet; a ringnet attached to bottom trawl; and optical platforms (Underwater Video Profiler (UVP) & Remotely Operated Vehicle (ROV)). Different sampling methodologies are shown to exhibit selectivity towards different groups of gelatinous zooplankton. Only ~21% of taxa caught during the survey were caught by both the macrozooplankton trawl and the Multinet when deployed at the same station. The estimates of gelatinous zooplankton abundance calculated using these two gear types also varied widely (1.4 ± 0.9 individuals 1000 m-3 estimated by the macrozooplankton trawl vs. 468.3 ± 315.4 individuals 1000 m-3 estimated by the Multinet (mean ± s.d.) when used at the same stations (n = 6). While it appears that traditional net sampling can generate useful data on pelagic cnidarians, comparisons with results from the optical platforms suggest that ctenophore diversity and abundance are consistently underestimated, particularly when net sampling is conducted in combination with formalin fixation. The results emphasise the importance of considering sampling methodology

  3. US AMLR Program zooplankton dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton research in the US AMLR Program focuses on the link between prey production, availability, and climate variability in relation to predator and fishery...

  4. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kü rten, Benjamin; Al-Aidaroos, Ali M.; Kurten, Saskia; El-Sherbiny, Mohsen M.; Devassy, Reny P.; Struck, Ulrich; Zarokanellos, Nikolaos; Jones, Burton; Hansen, Thomas; Bruss, Gerd; Sommer, Ulrich

    2015-01-01

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one

  5. Zooplankton From a Reef System Under the Influence of the Amazon River Plume

    Directory of Open Access Journals (Sweden)

    Sigrid Neumann-Leitão

    2018-03-01

    Full Text Available At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km2 that includes mainly large sponges but also rhodolith beds. The mesozooplankton associated with the pelagic realm over the reef formation was characterized, considering the estuarine plume and oceanic influence. Vertical hauls were carried out using a standard plankton net with 200 μm mesh size during September 2014. An indicator index was applied to express species importance as ecological indicators in community. Information on functional traits was gathered for the most abundant copepod species. Overall, 179 zooplankton taxa were recorded. Copepods were the richest (92 species, most diverse and most abundant group, whereas meroplankton were rare and less abundant. Species diversity (>3.0 bits.ind-1 and evenness (>0.6 were high, indicating a complex community. Small holoplanktonic species dominated the zooplankton, and the total density varied from 107.98 ind. m-3 over the reef area to 2,609.24 ind. m-3 in the estuarine plume, with a significant difference between coastal and oceanic areas. The most abundant copepods were the coastal species ithona plumifera and Clausocalanus furcatus and early stages copepodites of Paracalanidae. The holoplanktonic Oikopleura, an important producer of mucous houses, was very abundant on the reefs. The indicator species index revealed three groups: (1 indicative of coastal waters under the influence of the estuarine plume [Euterpina acutifrons, Parvocalanus crassirostris, Oikopleura (Vexillaria dioica and Hydromedusae]; (2 characterized coastal and oceanic conditions (Clausocalanus; (3 characterized the reef system (O. plumifera. Two major copepods functional groups were identified and sorted according to their trophic strategy and coastal-oceanic distribution. The species that dominated the coastal area and the area over the rhodolith beds are indicators of the estuarine

  6. Struktur Komunitas Zooplankton di Bendungan Telaga Tunjung, Kabupaten Tabanan-Bali

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    Ni Wayan Desy Wahyudiati

    2017-05-01

    Full Text Available Zooplankton are the heterotroph aquatic organisms and has a week swimming. Zooplankton acts as the first consumer in the waters, which utilize phytoplankton as their food. This research located in Telaga Tunjung reservoir, Timpag Village, Kerambitan Subdistrict, Tabanan Regency. The reservoir is used for industry, irrigation and tourism development. The aim of the research was to determine the community structure of zooplankton in Telaga Tunjung reservoir. This research was conducted from January to February 2016. Water sampling was conducted twice with a sampling interval of 2 weeks in 4 stations. There was a total of 23 species of zooplankton found, consisting of 6 classes: Eurotatoria (8 genera, Ciliatea (1 genera, Branchiopoda (4 genera, Monogononta (1 genera, Tubulinea (1 genera and Maxillopoda (3 genera. The most common species of zooplankton found in the sampling station were Polyarthra vulgaris (3.04 ind/l, Anuraeopsis coelata (1.28 ind/l, Keratella valga (0.43 ind/l, Vorticella sp. (0.49 ind/l, Diaphanosoma brachyurum (0.28 ind/l, Nauplius sp. (0.16 ind/l and Megacyclops viridis (1.16 ind/l. The average abundance of zooplankton was 9.38 ind/l. Based on the abundance of zooplankton, the trophic status of Telaga Tunjung reservoir is mesotrophic.

  7. Zooplankton structure in two interconnected ponds: similarities and differences

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    Špoljar Maria

    2016-03-01

    Full Text Available The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus Keratella as microfilter-feeder, and genera of Polyartha and Trihocerca as macrofilter-feeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran (Bosmina longirostris and larval and adult stages of macrofilter-feeder copepod (Macrocyclops albidus prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05 differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure.

  8. Effects of Climate on the Zooplankton of the California Current

    Science.gov (United States)

    Lavaniegos, B. E.

    2007-05-01

    Almost six decades of sampling of the California Current system, carried out by the CalCOFI program (California Cooperative Fisheries Investigation) complemented by a decade of observations from the IMECOCAL program (Investigaciones Mexicanas de la Corriente de California), have revealed changing patterns in zooplankton abundances, species composition, and distributions over interannual through multidecadal time scales. Interannual changes associated with ENSO variability are manifested as strong but transitory perturbations in the mean annual cycle in seasonal abundances (and distributions) of particular species. An investigation of longer- term change, limited to the region off southern California, shows a persistent decline in zooplankton volumes (a proxy for overall biomass of macrozooplankton) between 1977 and 1998 that is considered to be a response to the well documented shift in basin-scale climate forcing that occurred in 1976-77. Further examination of this decline in zooplankton volumes indicates that it was due principally to the disappearance of several salp species after 1977. Other species and functional groups did not decline after the change in climate regime, while some species have followed persistent secular trends that appear to be associated more with the phenomenon of long-term global warming. Differences in the regional responses to climate change throughout the California Current system have also been observed recently in the spatial distribution of zooplankton biomass and changes in latitudinal ranges of certain species. For example, zooplankton biomass in the Baja California region show typical values for the 1997-98 El Niño that were followed by a decrease during the sharp transition to the cool La Niña conditions in 1999. This contrasts with the nearby region off southern California that was characterized by reduced biomass during the El Niño period and the subsequent recovery during the La Niña. Another regional contrast in

  9. Zooplankton Distribution in Four Western Norwegian Fjords

    Science.gov (United States)

    Gorsky, G.; Flood, P. R.; Youngbluth, M.; Picheral, M.; Grisoni, J.-M.

    2000-01-01

    A multi-instrumental array constructed in the Laboratoire d'Ecologie du Plancton Marin in Villefranche sur mer, France, named the Underwater Video Profiler (UVP), was used to investigate the vertical distribution of zooplankton in four western Norwegian fjords in the summer 1996. Six distinct zoological groups were monitored. The fauna included: (a) small crustaceans (mainly copepods), (b) ctenophores (mainly lobates), (c) siphonophores (mainly physonects), (d) a scyphomedusa Periphylla periphylla, (e) chaetognaths and (f) appendicularians. The use of the non-disturbing video technique demonstrated that the distribution of large zooplankton is heterogeneous vertically and geographically. Furthermore, the abundance of non-migrating filter feeders in the deep basins of the fjords indicates that there is enough food (living and non-living particulate organic matter) to support their dietary needs. This adaptation may be considered as a strategy for survival in fjords. Specifically, living in dark, deep water reduces visual predation and population loss encountered in the upper layer due to advective processes.

  10. Mechanisms underlying recovery of zooplankton in Lake Orta after liming

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    Roberta Piscia

    2016-04-01

    Full Text Available The goal of this study was to improve the understanding of the large-scale mechanisms underlying the recovery of the zooplankton of Lake Orta from historical contamination, following reduced input of ammonia and metals and the subsequent 1989/90 liming intervention. The industrial pollution had been severe and long-lasting (1929-1990. Zooplankton biodiversity has improved, but most of the new taxa appearing in our counts are rotifers, while many calanoids and the large cladoceran predators (Bythotrephes and Leptodora that are common in the nearby Lake Maggiore, were still absent from Lake Orta 17 years after liming. To aid understanding of the large-scale mechanisms controlling changes in annual richness, we assessed the annual persistence (P of Crustacea and Rotifera taxa as an estimator of whether propagules that survived introduction, as result of the natural recolonization process, also thrived. We found that the rate of introduction of zooplankton colonists and their persistence in the water column of Lake Orta changed from 1971 to 2007. New rotifer taxa appeared in the lake after the mid-1980s, when discharge of toxic substances decreased, but their annual persistence was low (P<0.5 until the turn of the century. The numerical values of rotifer and crustacean persistence in Lake Orta were unexpectedly high in 2001 and 2007 (0.55 and 0.72 for rotifers, 0.85 and 0.86 for crustacean, respectively, much higher than in limed lakes in Sudbury, Canada, and in adjacent Lake Maggiore. We hypothesize this could be related to the lack of Cladoceran predators and zooplanktivorous fish in the pelagic waters of Lake Orta.

  11. Zooplankton variability in the Zuari estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Achuthankutty, C.T.; Nair, S.R.S.

    Short term variability in the secondary production and composition of zooplankton were studied during February to March 1979 by collecting zooplankton every alternate day from a station located near the mouth of Zuari. Irregularity in the production...

  12. Zooplankton size selection relative to gill raker spacing in rainbow trout

    Science.gov (United States)

    Budy, P.; Haddix, T.; Schneidervin, R.

    2005-01-01

    Rainbow trout Oncorhynchus mykiss are one of the most widely stocked salmonids worldwide, often based on the assumption that they will effectively utilize abundant invertebrate food resources. We evaluated the potential for feeding morphology to affect prey selection by rainbow trout using a combination of laboratory feeding experiments and field observations in Flaming Gorge Reservoir, Utah-Wyoming. For rainbow trout collected from the reservoir, inter-gill raker spacing averaged 1.09 mm and there was low variation among fish overall (SD = 0.28). Ninety-seven percent of all zooplankton observed in the diets of rainbow trout collected in the reservoir were larger than the interraker spacing, while only 29% of the zooplankton found in the environment were larger than the interraker spacing. Over the size range of rainbow trout evaluated here (200-475 mm), interraker spacing increased moderately with increasing fish length; however, the size of zooplankton found in the diet did not increase with increasing fish length. In laboratory experiments, rainbow trout consumed the largest zooplankton available; the mean size of zooplankton observed in the diets was significantly larger than the mean size of zooplankton available. Electivity indices for both laboratory and field observations indicated strong selection for larger-sized zooplankton. The size threshold at which electivity switched from selection against smaller-sized zooplankton to selection for larger-sized zooplankton closely corresponded to the mean interraker spacing for both groups (???1-1.2 mm). The combination of results observed here indicates that rainbow trout morphology limits the retention of different-sized zooplankton prey and reinforces the importance of understanding how effectively rainbow trout can utilize the type and sizes of different prey available in a given system. These considerations may improve our ability to predict the potential for growth and survival of rainbow trout within and

  13. Keystone taxa as drivers of microbiome structure and functioning.

    Science.gov (United States)

    Banerjee, Samiran; Schlaeppi, Klaus; van der Heijden, Marcel G A

    2018-05-22

    Microorganisms have a pivotal role in the functioning of ecosystems. Recent studies have shown that microbial communities harbour keystone taxa, which drive community composition and function irrespective of their abundance. In this Opinion article, we propose a definition of keystone taxa in microbial ecology and summarize over 200 microbial keystone taxa that have been identified in soil, plant and marine ecosystems, as well as in the human microbiome. We explore the importance of keystone taxa and keystone guilds for microbiome structure and functioning and discuss the factors that determine their distribution and activities.

  14. Biodiversity and community structure of zooplankton in the Sub-basin of Rio Poxim, Sergipe, Brazil

    Directory of Open Access Journals (Sweden)

    Eliane Maria de Souza Nogueira

    2011-08-01

    Full Text Available The zooplankton of aquatic environments is composed mostly of protozoans, rotifers, cladocerans and copepods, which play an important role in the food chain, transferring mass and energy from primary producers to higher trophic levels. This work was prepared with the objective of contributing to the knowledge of zooplankton biodiversity that occurs in the Sub-basin of Rio Poxim. Water samples were taken at monthly intervals at four sampling stations located along the sub-basin in the period August 2009 to July 2010. To obtain the zooplankton community, 100 L of water were filtered on nylon net with an aperture of 50 mm. Were identified 72 taxa distributed in the following taxonomic categories Rotifera, Protozoa, Porifera, Nematoda, Anellida, Cladocera, Copepoda, Ostracoda, Isopoda and Insecta. In terms of species richness, the phylum Rotifera followed by the Protoctista were the most relevant with forty and fifteen taxa, respectively. The most representative taxa in numerical terms were Arcella vulgaris, Notholca sp. Rotary sp. and nematodes. Regarding the community diversity index, the community was characterized as low diversity, but the taxa were distributed evenly in all monitoring points.

  15. Indicator Properties of Baltic Zooplankton for Classification of Environmental Status within Marine Strategy Framework Directive.

    Science.gov (United States)

    Gorokhova, Elena; Lehtiniemi, Maiju; Postel, Lutz; Rubene, Gunta; Amid, Callis; Lesutiene, Jurate; Uusitalo, Laura; Strake, Solvita; Demereckiene, Natalja

    2016-01-01

    The European Marine Strategy Framework Directive requires the EU Member States to estimate the level of anthropogenic impacts on their marine systems using 11 Descriptors. Assessing food web response to altered habitats is addressed by Descriptor 4 and its indicators, which are being developed for regional seas. However, the development of simple foodweb indicators able to assess the health of ecologically diverse, spatially variable and complex interactions is challenging. Zooplankton is a key element in marine foodwebs and thus comprise an important part of overall ecosystem health. Here, we review work on zooplankton indicator development using long-term data sets across the Baltic Sea and report the main findings. A suite of zooplankton community metrics were evaluated as putative ecological indicators that track community state in relation to Good Environmental Status (GES) criteria with regard to eutrophication and fish feeding conditions in the Baltic Sea. On the basis of an operational definition of GES, we propose mean body mass of zooplankton in the community in combination with zooplankton stock measured as either abundance or biomass to be applicable as an integrated indicator that could be used within the Descriptor 4 in the Baltic Sea. These metrics performed best in predicting zooplankton being in-GES when considering all datasets evaluated. However, some other metrics, such as copepod biomass, the contribution of copepods to the total zooplankton biomass or biomass-based Cladocera: Copepoda ratio, were equally reliable or even superior in certain basin-specific assessments. Our evaluation suggests that in several basins of the Baltic Sea, zooplankton communities currently appear to be out-of-GES, being comprised by smaller zooplankters and having lower total abundance or biomass compared to the communities during the reference conditions; however, the changes in the taxonomic structure underlying these trends vary widely across the sea basins due to

  16. Zooplankton in the Arctic outflow

    Science.gov (United States)

    Soloviev, K. A.; Dritz, A. V.; Nikishina, A. B.

    2009-04-01

    Climate changes in the Arctic cause the changes in the current system that may have cascading effect on the structure of plankton community and consequently on the interlinked and delicately balanced food web. Zooplankton species are by definition incapable to perform horizontal moving. Their transport is connected with flowing water. There are zooplankton species specific for the definite water masses and they can be used as markers for the different currents. That allows us to consider zooplankton community composition as a result of water mixing in the studied area. Little is known however about the mechanisms by which spatial and temporal variability in advection affect dynamics of local populations. Ice conditions are also very important in the function of pelagic communities. Melting time is the trigger to all "plankton blooming" processes, and the duration of ice-free conditions determines the food web development in the future. Fram Strait is one of the key regions for the Arctic: the cold water outflow comes through it with the East Greenland Current and meets warm Atlantic water, the West Spitsbergen Current, producing complicated hydrological situation. During 2007 and 2008 we investigated the structure functional characteristics of zooplankton community in the Fram Strait region onboard KV "Svalbard" (April 2007, April and May 2008) and RV "Jan Mayen" (May 2007, August 2008). This study was conducted in frame of iAOOS Norway project "Closing the loop", which, in turn, was a part of IPY. During this cruises multidisciplinary investigations were performed, including sea-ice observations, CTD and ADCP profiling, carbon flux, nutrients and primary production measurements, phytoplankton sampling. Zooplankton was collected with the Hydro-Bios WP2 net and MultiNet Zooplankton Sampler, (mouth area 0.25 m2, mesh size 180 um).Samples were taken from the depth strata of 2000-1500, 1500-1000, 1000-500,500-200, 200-100, 100-60, 60-30, 30-0 m. Gut fluorescence

  17. Impacts of algal blooms removal by chitosan-modified soils on zooplankton community in Taihu Lake,China

    Institute of Scientific and Technical Information of China (English)

    Jiajia Ni; Yuhe Yu; Weisong Feng; Qingyun Yan; Gang pan; Bo Yang; Xiang Zhang; Xuemei Li

    2010-01-01

    It is important to assess the effect on zooplankton when perform the environmental protection or restoration technology,especially removing algal blooms,because algae were the major primary producer in algal lakes.The influence on zooplankton community after half a year of algal blooms removed by chitosan-modified soils in Taihu Lake was assessed and the rationality of carrying out the process semiannually was evaluated in the present study.Morphological composition and genetic diversity of zooplankton community were investigated by microscope checkup and polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE).A total of 44 zooplankton taxa (23 protozoa,17 rotifers,3 copepoda and 1 cladocera) were detected by microscope checkup,and a total of 91 bands (28 bands amplified by primers F1427-GC and R1616,63 bands amplified by primers Fung-G-C and NS1) were detected by PCR-DGGE.The results of cluster analysis or detrended correspondence analysis indicated that there was no considerable difference in morphological composition of zooplankton and DGGE profiles between experimental and control sites,and DGGE profiles could represent the biologic diversity.The study showed that zooplankton community could recover original condition after half year of algal blooms removed by chitosan-modified soils and it was acceptable to apply this process semiannually.In addition,the results revealed that PCR-DGGE could be applied to investigate the impacts of the environmental protection or restoration engineering on zooplankton community diversity.

  18. Considerations on the biochemical composition of some freshwater zooplankton species.

    Directory of Open Access Journals (Sweden)

    Nicoletta RICCARDI

    1999-02-01

    Full Text Available The mean elemental (C, H, N and biochemical composition (lipids, carbohydrates and proteins of some abundant crustacean zooplankton species of Italian insubric lakes has been estimated by the analysis of samples collected at different seasons from various environments (Lake Maggiore, Lake Varese, Lake Comabbio, Lake Monate. From each sample an adequate number of specimens of each abundant species was sorted and analyzed by a CHN elemental analyzer. The percentage of lipids, carbohydrates and proteins and the calorific content were calculated from the elemental composition according to Gnaiger & Bitterlich (1984. Inter- and intraspecific variability of biochemical composition was quite high, while elemental composition and calorific content were less variable. An estimate of the mean elemental and biochemical composition of each species was obtained by pooling the data. These mean values have been used to estimate the pools of elements and compounds in the crustacean zooplankton of Lake Comabbio to provide an example of the importance of a multiple approach in zooplankton studies.

  19. Large-Scale Microzooplankton Abundance and Diversity in the North Sea in Mid-Winter

    Science.gov (United States)

    Bils, F.; Moyano, M.; Peck, M. A.

    2016-02-01

    Protists and other microzooplankters (20-200 µm) are often not sampled in ecosystem monitoring programs despite the trophodynamic importance of this size fraction as grazers in the microbial loop and as prey for larger zooplankton and early larval stages of fish. We investigated the microzooplankton composition, diversity and abundance at 40 stations across the North Sea (from 3.2° W-7.6° E and 50.5-59.8°N) in mid-winter of 2014. Microzooplankton was collected with a CTD rosette at 10 m depth and manually counted and identified to the lowest possible taxa. A total of 35 taxa of dinoflagellates and ciliates was identified. Gymnodinium spp and Torodinium sp contributed most to the total dinoflagellate abundance (34 and 24 %) and Strombidium spp was the most abundant ciliate taxon (52 % of total ciliate abundance). Total microzooplankton biomass ranged between 0.08 and 2.4 µg C *L-1, much lower than those observed in spring or summer (up to > 100 µgC L-1). The highest biomass (> 0.5 µgC L-1) were found in the English Channel, south of 52°N, in contrast with those calculated for stations north of 57°N (< 0.2 µgC L-1). Changes in the community composition will be discussed in relation to observed gradients in hydrographic conditions and the ability of microzooplankton to support dietary requirements of overwintering larvae of marine fishes.

  20. Effects of liming and development of Curimbatá (Prochilodus lineatus larvae on the abundance of zooplankton in fish ponds Efeitos da calagem e desenvolvimento do Curimbatá (Prochilodus lineatus na abundância do zooplâncton em viveiros de piscicultura

    Directory of Open Access Journals (Sweden)

    Thécia Alfenas Silva Valente Paes

    2011-12-01

    Full Text Available AIM: We aimed to evaluate the influence of the correction of the water alkalinity in the fish ponds on the density of zooplankton under a period they were stocked with larvae of Prochilodus lineatus, a neotropical fish called "Curimbatá". METHODS: We used a factorial design completely randomized. In one plot (2 ponds there was no correction of the alkalinity of the water (20 mg CaCO3.L-1 and in two others, this variable was adjusted weekly to values around 30 and 60 mg CaCO3.L-1 ¹, with two replicates each. Zooplankton was sampled weekly and the experiment lasted 63 days. RESULTS: Significant differences in the density of the zooplankton over time (F = 6.78, p OBJETIVO: Nosso objetivo foi avaliar a influencia da correção da alcalinidade da água em viveiros de piscicultura na densidade do zooplâncton em período em que foram estocados com larvas de Prochilodus lineatus, um peixe neotropical denominado "Curimbatá". MÉTODOS: Foi utilizado um delineamento experimental fatorial, inteiramente causualizado. Em um tratamento (2 viveiros, não houve correção da alcalinidade da água, e em outros dois viveiros, a alcalinidade foi ajustada semanalmente para valores em torno de 30 e 60 mg CaCO3.L-1, com duas réplicas cada. Os organismos zooplanctônicos foram coletados semanalmente durante 63 dias. RESULTADOS: Diferenças significativas foram observadas na densidade do zooplâncton ao longo do tempo (F = 6,78, p < 0,05 e um decréscimo acentuado na densidade do zooplâncton foi observado da primeira para a segunda semana, e pequenos aumentos sucessivos na densidade da quarta semana até o final do experimento. Ao considerar todo o período experimental, a alcalinidade corrigida para 60 mg CaCO3.L-1 resultou em maiores densidades de zooplâncton. Ocorreram grandes mudanças na composição zooplanctônica. Rotifera foram dominantes no início do experimento e Cladocera e Copepoda nas últimas semanas, possivelmente devido a uma interação da

  1. Zooplankton assemblages and biomass during a 4-period survey in a northern Mediterranean coastal lagoon.

    Science.gov (United States)

    Lam-Hoai, T; Rougier, C

    2001-01-01

    The authors proposed to examine zooplankton biomass at three stations inside (T and Z) and outside (M) a coastal lagoon of the north-western Mediterranean Sea. Station T represented the lagoon central area, and station Z was positioned in a shellfish farming sector, while the seaside station (M) served as a reference of marine environment. Analyses were designed to outline the net zooplankton assemblages (taxonomic structures and length distributions) in different environmental conditions, including the farming activity. A discriminant analysis of environmental variables determined that temperature, salinity and phytoplankton implied mainly in spatial pattern of the samples. An ordination of taxa biomasses showed two main factors which might contribute to the organisation of the zooplankton assemblages: the geographical position and the thermal period. The geographical position integrated the lagoon-sea water exchange under forcing parameters (habitat, tides and winds). The thermal period reflected both the populations development cycles and the environmental constraints (temperature, salinity, trophic resources). The resulting effects appeared in structured zooplankton assemblages in space and time. The number of 50 microns interval length classes and of taxa decreased from the seaside and the lagoon central area free of farming activity to the shallower farming zone. But the biomass-length distribution profiles did not closely follow such an expected opposition between opened and confined areas: more extended profiles were observed at station Z. Biomass dominant size classes concerned the range up to 300 microns. This size category appeared to collapse in terms of biomass from the seaside or central area of the lagoon towards the farming area, similarly to zooplankton global biomass fluctuations. Difference between biomass levels and between biomass structures suggested that net zooplankton partly acted as food competitors of macro-filtering organisms, and as

  2. Diel distribution of zooplankton at the Mobil OTEC site (29/sup 0/N 88/sup 0/W) in the Northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Steen, Jr, J P; Gunter, G; Hartwig, E O

    1982-01-01

    In the study 128 copepod species and 43 other zooplankton taxa were identified from four depth strata (0 to 50 m, 50 to 100 m, 100 to 300 m and 300 to 500 m). Duplicate step-oblique tows at six hour intervals over 24 hours were taken at a site in the Gulf of Mexico. The distribution of zooplankton numbers and sizes, and species diversity, richness and evenness through a diel period are described.

  3. ZOOPLANKTON COMMUNITY STRUCTURE OF THE SEA SURFACE MICROLAYER NEAR NUCLEAR POWER PLANTS AND MARINE FISH CULTURE ZONES IN DAYA BAY

    Institute of Scientific and Technical Information of China (English)

    杨宇峰; 王肇鼎; 潘明祥; 焦念志

    2002-01-01

    The authors' surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of thesea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02-0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2-2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.``

  4. The Impacts of Recently Established Fish Populations on Zooplankton Communities in a Desert Spring, and Potential Conflicts in Setting Conservation Goals

    Directory of Open Access Journals (Sweden)

    Sujan M. Henkanaththegedara

    2015-01-01

    Full Text Available Desert springs, which harbor diverse and endemic invertebrate assemblages, are often used as refuge habitats for protected fish species. Additionally, many of these springs have been colonized by invasive fish species. However, the potential impacts of recently established fish populations on invertebrate communities in desert springs have been relatively unexplored. We conducted a mesocosm experiment to assess the impact of both protected and invasive fish on community structure of spring-dwelling invertebrates focusing on zooplankton. Experimental populations of spring zooplankton communities were established and randomly assigned to one of three treatments, (1 invasive western mosquitofish (Gambusia affinis; (2 endangered Mohave tui chub (Siphateles bicolor mohavensis; and (3 fishless control. Final populations of zooplankton and fish were sampled, sorted, identified and counted. The treatment differences of zooplankton communities were analyzed by comparing the densities of six major zooplankton taxa. Further, we performed nonmetric multidimensional scaling (NMDS to visualize the patterns of zooplankton community assemblages. Four zooplankton taxa, crustacean nauplii, cladocera, calanoid and cyclopoid copepods had significantly lower densities in fish treatments compared to fishless control. Overall, invasive mosquitofish caused a 78.8% reduction in zooplankton density, while Mohave tui chub caused a 65.1% reduction. Both protected and invasive fish had similar effects on zooplankton except for cladocerans where tui chub caused a 60% reduction in density, whereas mosquitofish virtually eliminated cladocerans. The presence of fish also had a significant effect on zooplankton community structure due to population declines and local extirpations presumably due to fish predation. This work shows that conservation-translocations undertaken to conserve protected fish species may impact spring-dwelling invertebrate communities, and such impacts are

  5. Nutrients, phytoplankton, zooplankton, and macrobenthos

    Science.gov (United States)

    Rudstam, Lars G.; Holeck, Kristen T.; Watkins, James M.; Hotaling, Christopher; Lantry, Jana R.; Bowen, Kelly L.; Munawar, Mohi; Weidel, Brian C.; Barbiero, Richard; Luckey, Frederick J.; Dove, Alice; Johnson, Timothy B.; Biesinger, Zy

    2017-01-01

    Lower trophic levels support the prey fish on which most sport fish depend. Therefore, understanding the production potential of lower trophic levels is integral to the management of Lake Ontario’s fishery resources. Lower trophic-level productivity differs among offshore and nearshore waters. In the offshore, there is concern about the ability of the lake to support Alewife (Table 1) production due to a perceived decline in productivity of phytoplankton and zooplankton whereas, in the nearshore, there is a concern about excessive attached algal production (e.g., Cladophora) associated with higher nutrient concentrations—the oligotrophication of the offshore and the eutrophication of the nearshore (Mills et al. 2003; Holeck et al. 2008; Dove 2009; Koops et al. 2015; Stewart et al. 2016). Even though the collapse of the Alewife population in Lake Huron in 2003 (and the associated decline in the Chinook Salmon fishery) may have been precipitated by a cold winter (Dunlop and Riley 2013), Alewife had not returned to high abundances in Lake Huron as of 2014 (Roseman et al. 2015). Failure of the Alewife population to recover from collapse has been attributed to declines in lower trophic-level production (Barbiero et al. 2011; Bunnell et al. 2014; but see He et al. 2015). In Lake Michigan, concerns of a similar Alewife collapse led to a decrease in the number of Chinook Salmon stocked. If lower trophic-level production declines in Lake Ontario, a similar management action could be considered. On the other hand, in Lake Erie, which supplies most of the water in Lake Ontario, eutrophication is increasing and so are harmful algal blooms. Thus, there is also a concern that nutrient levels and algal blooms could increase in Lake Ontario, especially in the nearshore. Solutions to the two processes of concern—eutrophication in the nearshore and oligotrophication in the offshore—may be mutually exclusive. In either circumstance, fisheries management needs information on

  6. Some ecological implications of a neem (azadirachtin) insecticide disturbance to zooplankton communities in forest pond enclosures.

    Science.gov (United States)

    Kreutzweiser, David P; Sutton, Trent M; Back, Richard C; Pangle, Kevin L; Thompson, Dean G

    2004-04-28

    A neem-based insecticide, Neemix 4.5, was applied to forest pond enclosures at concentrations of 10, 17, and 28 microg l(-1) azadirachtin (the active ingredient). At these test concentrations, significant, concentration-dependent reductions in numbers of adult copepods were observed, but immature copepod and cladoceran populations were unaffected. There was no evidence of recovery of adult copepods within the sampling season (May to October). The ecological significance of this disturbance to the zooplankton community was examined by determining biomass as a measure of food availability for higher predators, plankton community respiration, dissolved oxygen (DO) concentrations, and conductivity as functional indicators of ecosystem stress, and zooplankton food web stability as a measure of effects on trophic structure. The selective removal or reduction of adult copepods was sufficient to measurably reduce total zooplankton biomass for several weeks mid-season. During the period of maximal impact (about 4-9 weeks after the applications), total plankton community respiration was significantly reduced, and this appeared to contribute to significant, concentration-dependent increases in dissolved oxygen and decreases in conductivity among treated enclosures. The reductions in adult copepods resulted in negative effects on zooplankton food web stability through eliminations of a trophic link and reduced interactions and connectance. Comparing the results here to those from a previous study with tebufenozide, which was selectively toxic to cladocerans and had little effect on food web stability, indicates that differential sensitivity among taxa can influence the ecological significance of pesticide effects on zooplankton communities.

  7. Empirical relationships between phytoplankton and zooplankton biomass in Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.

    and temperature, zooplankton and phytoplankton, zooplankton and PO sub(4)-P and phytoplankton and PO sub(4)-P. Linear regression model is found to be significant at 1% level of significance. Since zooplankton and phytoplankton are significantly positively...

  8. Productivity, trophic levels and size spectra of zooplankton in northern Norwegian shelf regions

    Science.gov (United States)

    Zhou, Meng; Tande, Kurt S.; Zhu, Yiwu; Basedow, Sünnje

    2009-10-01

    Many studies have been conducted in northern Norwegian shelf regions to assess distributions and abundances of zooplankton in the last decade using towed Scanfish-conductivity, temperature and depth sensors (CTD)-optical plankton counter (OPC), and plankton nets. Significant progresses have been made in understanding dominant species, life histories and behavior, and in using size-structured data to identify dominant species in a certain size range. Using these Scanfish-CTD-OPC data, the analysis of zooplankton community size structures, compositions and their relationships with water types is made along the shelf region from Lofoten, North Cape to Varangerfjorden. From the relationships between the water types and zooplankton communities, the transports and exchanges of zooplankton communities between the Norwegian Coastal and Norwegian Atlantic Waters in regions near Malangsgrunnen and Nordvestbanken are examined. The biovolume (biomass) spectra are further analyzed for the productivity, trophic levels and seasonality of communities in these regions, indicating a steeper slope of the biovolume spectrum for a community dominated by herbivorous species in spring and a flatter slope for a community dominated by carnivorous-omnivorous species in winter. The comparison with the zooplankton biovolume spectra obtained in areas west of Antarctic Peninsula is made to examine and understand the differences in the zooplankton biovolume spectra, their trophic dynamics and potential human impacts between different regions.

  9. Eutrophication and warming effects on long-term variation of zooplankton in Lake Biwa

    Directory of Open Access Journals (Sweden)

    C. H. Hsieh

    2011-05-01

    Full Text Available We compiled and analyzed long-term (1961–2005 zooplankton community data in response to environmental variations in Lake Biwa. Environmental data indicate that Lake Biwa had experienced eutrophication (according to the total phosphorus concentration in the late 1960s and recovered to a normal trophic status around 1985, and then has exhibited warming since 1990. Total zooplankton abundance showed a significant correlation with total phytoplankton biomass. Following a classic pattern, the cladoceran/calanoid and cyclopoid/calanoid abundance ratio was related positively to eutrophication. The zooplankton community exhibited a significant response to the boom and bust of phytoplankton biomass as a consequence of eutrophication-reoligotriphication and warming. Moreover, our analyses suggest that the Lake Biwa ecosystem exhibited a hierarchical response across trophic levels; that is, higher trophic levels may show a more delayed response or no response to eutrophication than lower ones.

    We tested the hypothesis that the phytoplankton community can better explain the variation of the zooplankton community than bulk environmental variables, considering that the phytoplankton community may directly affect the zooplankton succession through predator-prey interactions. Using a variance partition approach, however, we did not find strong evidence to support this hypothesis. We further aggregated zooplankton according to their feeding types (herbivorous, carnivorous, omnivorous, and parasitic and taxonomic groups, and analyzed the aggregated data. While the pattern remains similar, the results are less clear comparing the results based on finely resolved data. Our research suggests that zooplankton can be bio-indicators of environmental changes; however, the efficacy depends on data resolution.

  10. Behind the impact of introduced trout in high altitude lakes: adult, not juvenile fish are responsible of the selective predation on crustacean zooplankton

    Directory of Open Access Journals (Sweden)

    Rocco Tiberti

    2014-05-01

    Full Text Available Introduced fish seriously affect zooplankton communities in mountain lakes, often leading to the loss of large species. Selective predation is recognized to be the ultimate cause of such a strong impact. Here we describe the selection of zooplankton prey by analyzing the stomach contents of more than 300 brook trout (Salvelinus fontinalis inhabiting seven alpine lakes in the Gran Paradiso National Park (western Italian Alps. Our results show that planktivory is much more common in young fish, which feed on a larger number of taxa, but also adult fish maintain the ability to feed on zooplankton. There is a direct dependence between the length of zooplankton prey and the length of their fish predators, and adult, not juvenile fish are responsible of the selective predation on large crustacean zooplankton, which drive the impact of introduced fish throughout the entire zooplankton community. In some rare cases, large zooplankton populations develop in the presence of brook trout, and planktivory can become an important temporary resource for adult fish during the ice-free season. Thus, in the early stages of the establishment of non-native trout in alpine lakes, large-bodied zooplankton may represent an important food resource.

  11. Zooplankton trophic niches respond to different water types of the western Tasman Sea: A stable isotope analysis

    Science.gov (United States)

    Henschke, Natasha; Everett, Jason D.; Suthers, Iain M.; Smith, James A.; Hunt, Brian P. V.; Doblin, Martina A.; Taylor, Matthew D.

    2015-10-01

    The trophic relationships of 21 species from an oceanic zooplankton community were studied using stable isotopes of carbon and nitrogen. Zooplankton and suspended particulate organic matter (POM) were sampled in three different water types in the western Tasman Sea: inner shelf (IS), a cold core eddy (CCE) and a warm core eddy (WCE). δ15N values ranged from 3.9‰ for the parasitic copepod Sapphirina augusta to 10.2‰ for the euphausiid, Euphausia spinifera. δ13C varied from -22.6 to -19.4‰ as a result of the copepod Euchirella curticauda and E. spinifera. The isotopic composition of POM varied significantly among water types; as did the trophic enrichment of zooplankton over POM, with the lowest enrichment in the recently upwelled IS water type (0.5‰) compared to the warm core eddy (1.6‰) and cold core eddy (2.7‰). The WCE was an oligotrophic environment and was associated with an increased trophic level for omnivorous zooplankton (copepods and euphausiids) to a similar level as carnivorous zooplankton (chaetognaths). Therefore carnivory in zooplankton can increase in response to lower abundance and reduced diversity in their phytoplankton and protozoan prey. Trophic niche width comparisons across three zooplankton species: the salp Thalia democratica, the copepod Eucalanus elongatus and the euphausiid Thysanoessa gregaria, indicated that both niche partitioning and competition can occur within the zooplankton community. We have shown that trophic relationships among the zooplankton are dynamic and respond to different water types. The changes to the zooplankton isotopic niche, however, were still highly variable as result of oceanographic variation within water types.

  12. Organic carbon content of tropical zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    In the Zuari and Mandovi estuaries variations in organic carbon of zooplankton are 26.4-38.8 and 24-39.9% of dry weight respectively. Maximum carbon content of estuarine zooplankton is observed in November. Organic carbon in nearshore and oceanic...

  13. Zooplankton of the Zaporiz’ke Reservoir

    Directory of Open Access Journals (Sweden)

    T. V. Mykolaichuk

    2006-01-01

    Full Text Available The paper is devoted to zooplankton species composition in the Zaporiz’ke Reservoir. The greatest species diversity was found in the macrophyte communities of the upper reservoir’s littoral, but the least zooplankton diversity – in the pelagic zone of the lower reservoir.

  14. Composition, Abundance and Distribution of Brachyuran Larvae in ...

    African Journals Online (AJOL)

    ... Ocypodidae, Grapsidae and Xanthidae. Abundance of brachyuran larvae was significantly positively correlated with total zooplankton abundance (r2 = 0.8) and salinity (r2 = 0.71). Keywords: Brachyuran larvae, abundance, composition, Mida creek, Kenya West Indian Ocean Journal of Marine Science Vol. 3 (2) 2004: pp.

  15. Spatial patterns of littoral zooplankton assemblages along a salinity gradient in a brackish sea: A functional diversity perspective

    Science.gov (United States)

    Helenius, Laura K.; Leskinen, Elina; Lehtonen, Hannu; Nurminen, Leena

    2017-11-01

    The distribution patterns and diversity of littoral zooplankton are both key baseline information for understanding the functioning of coastal ecosystems, and for identifying the mechanisms by which the impacts of recently increased eutrophication are transferred through littoral food webs. In this study, zooplankton community structure and diversity along a shallow coastal area of the northern Baltic Sea were determined in terms of horizontal environmental gradients. Spatial heterogeneity of the zooplankton community was examined along the gradient. Altogether 31 sites in shallow sandy bays on the coast of southwest Finland were sampled in the summer periods of 2009 and 2010 for zooplankton and environmental variables (surface water temperature, salinity, turbidity, wave exposure, macrophyte coverage, chlorophyll a and nutrients). Zooplankton diversity was measured as both taxonomic as well as functional diversity, using trait-based classification of planktonic crustaceans. Salinity, and to a lesser extent turbidity and temperature, were found to be the main predictors of the spatial patterns and functional diversity of the zooplankton community. Occurrence of cyclopoid copepods, as well as abundances of the calanoid copepod genus Acartia and the rotifer genus Keratella were found to be key factors in differentiating sites along the gradient. As far as we know, this is the first extensive study of functional diversity in Baltic Sea coastal zooplankton communities.

  16. Evaluation of sound extinction and echo interference in densely aggregated zooplankton

    Directory of Open Access Journals (Sweden)

    Natalia Gorska

    2000-09-01

    Full Text Available The investigation of sound extinction and echo interference is important as regards the accurate assessment of the abundance of densely aggregated zooplankton. To study these effects,the analytical model describing sound backscattering by an aggregation of isotropic scatterers (Rytov et al. 1978, Sun & Gimenez 1992 has been extended to the case of densely aggregated elongated zooplankton. The evaluation of the effects in the case of a dense krill aggregation demonstrates that they can be significant and should be taken into account.

  17. Trace metal concentrations in marine zooplankton from the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; Balachandran, K.K.; Nair, M.; Joseph, T.

    on the interrelationships of zooplankton and phytoplankton. – Journal of Marine Biological Association U.K 32: 375-445. [2] Brooks, R.R., Presley, B.J., Kaplan, I.R. (1967): APDC-MIBK extraction system for the determination of trace elements in saline waters by Atomic... of contaminants in the food web dynamics as well as in the biogeochemical cycling of trace elements. Zooplanktons are the most abundant animals in the sea, which play an important role in the marine food chain. They mostly feed on phytoplankton and in turn...

  18. Stable isotope methods: The effect of gut contents on isotopic ratios of zooplankton

    Science.gov (United States)

    Hill, J. M.; McQuaid, C. D.

    2011-05-01

    In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0-2.0, 2.0-4.0 and >4.0 mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations. The δ15N ratios were influenced by zooplankton size class, presumably reflecting ontogenetic changes in diet. ANOVA post hoc results and correlations in δ15N signatures among treatments suggest that gut contents may not affect overall nitrogen signatures of Euphausia spp., but that δ13C signatures may be significantly altered by their presence. Carbon interpretations however, were complicated by potential effects of variation in chitin, lipids and metabolism among tissues and the possibility of opportunistic omnivory. Consequently we advocate gut evacuation before sacrifice in euphausiids if specific tissue dissection is impractical and recommend

  19. Diel vertical migration of zooplankton in the Tanzanian waters of ...

    African Journals Online (AJOL)

    The diel vertical migration of zooplankton was studied in the Southern part of Lake Victoria in January and July 2002. A van dorn water sampler was used to collect zooplankton. In January 2002, zooplankton showed a pronounced diel vertical migration whereby zooplankton were moving upward at around sunset and ...

  20. Reaction of fresh water zooplankton community to chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, D.; Pryakhin, E. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Ivanov, I. [FSUE Mayak PA (Russian Federation)

    2014-07-01

    The characteristic features of ecological community as a whole and cenosis of zooplankton organisms as part of it determine the intensity of the processes of self-purification of water and the formation of a particular body of water. Identifying features of the structure and composition of the zooplankton community of aquatic ecosystems exposed to different levels of radiation exposure, it is necessary to identify patterns of changes in zooplankton and hydro-biocenosis as a whole. Industrial reservoirs, the storage of liquid low-level radioactive waste 'Mayak' for decades, have high radiation load. A large range of levels of radioactive contamination (total volume beta-activity in water varies from 2.2x10{sup 3} to 2.3x10{sup 7} Bq/l, total volume alpha-activity - from 2.6x10{sup -1} to 3.1x10{sup 3} Bq/l) provides a unique opportunity to study ecosystems in a number of reservoirs with increasing impact of radiation factor. We studied five reservoirs that were used as the storage of low-and intermediate-level liquid radioactive waste pond and one comparison water body. In parallel with zooplankton sampling water samples were collected for hydro-chemical analysis. 41 indicators were analysed in order to assess the water chemistry. To determine the content of radionuclides in the various components of the ecosystem samples were collected from water, bottom sediments and plankton. Sampling of zooplankton for the quantitative analysis was performed using the method of weighted average auto bathometer. Apshteyn's plankton net of the surface horizon was used for qualitative analysis of the species composition of zooplankton. Software package ERICA Assessment Tool 2012 was used for the calculation of the absorbed dose rate. Species diversity and biomass of zooplankton, the share of rotifers in the number of species, abundance and biomass decrease with the increase of the absorbed dose rate and salinity. The number of species in a sample decreases with the

  1. Zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Madhu, N.V.

    , based on Gauns (2000), indicates the presence of a rich microzooplankton community in the Mandovi and Zuari estuaries. The community is qualitatively and quantitatively dominated by ciliated protozoans (e.g., tintinnids), with nearly 60 species recorded...; Oceanography and Marine Biology: An Annual Review 28 381?496. ?lvares Claude (2002) Fish, Curry and Rice (Revised 4th edn.). Goa Foundation. Alzieu C. (2000) Environmental impact of TBT: the French experience; Science of the Total Environment 258 99?102. Alzieu...

  2. Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

    Directory of Open Access Journals (Sweden)

    Leonardo C. e Souza

    2011-06-01

    Full Text Available Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods. The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

  3. Improved protocols to accelerate the assembly of DNA barcode reference libraries for freshwater zooplankton.

    Science.gov (United States)

    Elías-Gutiérrez, Manuel; Valdez-Moreno, Martha; Topan, Janet; Young, Monica R; Cohuo-Colli, José Angel

    2018-03-01

    Currently, freshwater zooplankton sampling and identification methodologies have remained virtually unchanged since they were first established in the beginning of the XX century. One major contributing factor to this slow progress is the limited success of modern genetic methodologies, such as DNA barcoding, in several of the main groups. This study demonstrates improved protocols which enable the rapid assessment of most animal taxa inhabiting any freshwater system by combining the use of light traps, careful fixation at low temperatures using ethanol, and zooplankton-specific primers. We DNA-barcoded 2,136 specimens from a diverse array of taxonomic assemblages (rotifers, mollusks, mites, crustaceans, insects, and fishes) from several Canadian and Mexican lakes with an average sequence success rate of 85.3%. In total, 325 Barcode Index Numbers (BINs) were detected with only three BINs (two cladocerans and one copepod) shared between Canada and Mexico, suggesting a much narrower distribution range of freshwater zooplankton than previously thought. This study is the first to broadly explore the metazoan biodiversity of freshwater systems with DNA barcodes to construct a reference library that represents the first step for future programs which aim to monitor ecosystem health, track invasive species, or improve knowledge of the ecology and distribution of freshwater zooplankton.

  4. Ingestion of microplastics by natural zooplankton groups in the northern South China Sea.

    Science.gov (United States)

    Sun, Xiaoxia; Li, Qingjie; Zhu, Mingliang; Liang, Junhua; Zheng, Shan; Zhao, Yongfang

    2017-02-15

    The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505μm and 160μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125μm and 167μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1pieces/m 3 for Net I and 131.5pieces/m 3 for Net II. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Zooplankton diversity of a protected and vulnerable wetland system in southern South America (Llancanelo area, Argentina

    Directory of Open Access Journals (Sweden)

    D. Sabina D’Ambrosio

    2016-02-01

    Full Text Available Abstract In arid regions, climatic conditions exert a great control on the aquatic systems present, but recent changes in climate have produced an enhanced salinization of the aquatic environments located there. Consequently, a major reduction in biodiversity would be expected in those wetlands that were originally fresh water. Salinity is a principal cause of reduced biodiversity particularly in zooplankton because few of those species can adapt to the salt pressure of saline environments. Therefore, the aim of this study was to gain essential information on the diversity of aquatic invertebrates in Llancanelo basin by focussing the analysis on the zooplankton community and exploring seasonal and spatial differences in the zooplankton assemblages of this vulnerable wetland system within an arid region of Argentina. Seasonal samples were taken at nine sites in the basin (a shallow lake, 4 springs, streams, and the Malargüe River. A total of 45 species were identified. The zooplankton abundance in the lake displayed a clear seasonal contrast and was higher than that recorded in the springs and lotic environments. Boeckella poopoensis, Fabrea salina, and Brachionus plicatilis predominated in the lake, indicating their halophilia. The presence of the crustaceans Alona sp., Macrocyclops albidus, and Paracyclops fimbriatus was restricted to the springs; whereas Notholca labis and Notholca squamula were found only in running water. The zooplankton species richness in the Llancanelo area is low because of both the salt content in the lake and the irregularity of freshwater entry in all locations during the annual cycle.

  6. Zooplankton and ichthyoplankton distribution on the southern Brazilian shelf: an overview

    Directory of Open Access Journals (Sweden)

    Rubens M. Lopes

    2006-06-01

    Full Text Available The southern Brazilian coast is the major fishery ground for the Brazilian sardine (Sardinella brasiliensis, a species responsible for up to 40% of marine fish catches in the region. Fish spawning and recruitment are locally influenced by seasonal advection of nutrient-rich waters from both inshore and offshore sources. Plankton communities are otherwise controlled by regenerative processes related to the oligotrophic nature of the Tropical Water from the Brazil Current. As recorded in other continental margins, zooplankton species diversity increases towards outer shelf and open ocean waters. Peaks of zooplankton biomass and ichthyoplankton abundance are frequent on the inner shelf, either at upwelling sites or off large estuarine systems. However, meandering features of the Brazil Current provide an additional mechanism of upward motion of the cold and nutrient-rich South Atlantic Central Water, increasing phyto- and zooplankton biomass and production on mid- and outer shelves. Cold neritic waters originating off Argentina, and subtropical waters from the Subtropical Convergence exert a strong seasonal influence on zooplankton and ichthyoplankton distribution towards more southern areas. This brief review highlights the need for further experimental studies on zooplankton life cycle strategies in order to understand the major processes controlling food web dynamics in this shelf ecosystem.

  7. Variability of zooplankton communities at Condor seamount and surrounding areas, Azores (NE Atlantic)

    Science.gov (United States)

    Carmo, Vanda; Santos, Mariana; Menezes, Gui M.; Loureiro, Clara M.; Lambardi, Paolo; Martins, Ana

    2013-12-01

    Seamounts are common topographic features around the Azores archipelago (NE Atlantic). Recently there has been increasing research effort devoted to the ecology of these ecosystems. In the Azores, the mesozooplankon is poorly studied, particularly in relation to these seafloor elevations. In this study, zooplankton communities in the Condor seamount area (Azores) were investigated during March, July and September 2010. Samples were taken during both day and night with a Bongo net of 200 µm mesh that towed obliquely within the first 100 m of the water column. Total abundance, biomass and chlorophyll a concentrations did not vary with sampling site or within the diel cycle but significant seasonal variation was observed. Moreover, zooplankton community composition showed the same strong seasonal pattern regardless of spatial or daily variability. Despite seasonal differences, the zooplankton community structure remained similar for the duration of this study. Seasonal variability better explained our results than mesoscale spatial variability. Spatial homogeneity is probably related with island proximity and local dynamics over Condor seamount. Zooplankton literature for the region is sparse, therefore a short review of the most important zooplankton studies from the Azores is also presented.

  8. Abundância do zooplâncton em diferentes zonas (pelágica e litorânea e horários (manhã e noite em dois lagos meândricos amazônicos - DOI: 10.4025/actascibiolsci.v25i2.2011 Abundance of zooplankton from different zones (pelagic and littoral and time periods (morning and night in two Amazonian meandering lakes - DOI: 10.4025/actascibiolsci.v25i2.2011

    Directory of Open Access Journals (Sweden)

    Erlei Cassiano Keppeler

    2003-04-01

    Full Text Available Durante 10 meses foi estudada a abundância do zooplâncton em dois lagos da Amazônia Sul-Ocidental, situados respectivamente nas coordenadas 10°02'36''S; 67°50'24''W (Lago Amapá e 9°27'21"S; 67°31'39"W (Lago Pirapora. Ambos os lagos caracterizam-se como de meandro abandonado. O objetivo desse estudo foi comparar as regiões pelágica e litorânea, com base na abundäncia da comunidade zooplanctönica, bem como observar diferenças da distribuição dessa comunidade na coluna da água no período da manhã e noite. As coletas foram realizadas com filtragem em rede de zooplâncton (55µm e posterior passagem em garrafa de Van Dorn de 5L. Coletou-se 4L na superfície e 5L nas camadas do meio e fundo, totalizando 14L de água para cada estação de coleta. Adicionalmente, foram medidos parâmetros físicos e químicos como transparência, temperatura, pH, oxigênio dissolvido, condutividade elétrica e turbidez. Anova (análise de variância e teste de Tukey foram usados. Não houve diferença estatística significativa nem para as regiões estudadas como também para os diferentes horários observados. Os resultados dos coeficientes de correlação de Pearson (p Moina spp. (representados por Moina minuta e Moina reticulata e Ceriodaphnia reticulata. Daphnia gessneri também apresentou correlação com ChaoboridaeThe abundance of zooplankton in two lakes of Southwest Amazonia was studied for 10 months in different regions and at different periods of the day. The lakes were Lago Amapá, located at 10°02'36''S, 67°50'24''W, and Lago Pirapora, at 9°27'21"S, 67°31'39". Both lakes are characterized as oxbow lakes. The aim of this study was to compare the pelagic and littoral regions, as well as to determine differences in the distribution of zooplankton in the water column in the morning and at night. Collections were made by filtering water through a 55µm zooplankton net into a 5L Van Dorn bottle, collecting 4L from the top and 5L from the

  9. Ecological factors affecting the distribution of zooplankton ...

    African Journals Online (AJOL)

    USER

    and ecological functioning of aquatic ecosystems, which must be taken into account ... zooplankton, which is its key position in the trophic chain, gives a fundamental role ..... suspended solids can block the filtering apparatus and impede their ...

  10. Diurnal variation of zooplankton off Versova (Bombay)

    Digital Repository Service at National Institute of Oceanography (India)

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

    Physicochemical parameters and diurnal variaion of zooplankton were studied off Versova on 17/18 February 1981. Salinity and dissolved oxygen showed limited variation during the period of study. Nutrient values followed the tidal rhythm and high...

  11. Trait-based approaches to zooplankton communities

    DEFF Research Database (Denmark)

    Lichtman, E.; Ohman, M.D.; Kiørboe, Thomas

    2013-01-01

    in ecosystem models. Characterizing zooplankton traits and trade-offs will also be helpful in understanding the selection pressures and diversity patterns that emerge in different ecosystems along major environmental gradients. Zooplankton traits can be characterized according to their function and type. Some......; develop novel predictive models that explicitly incorporate traits and associated trade-offs; and utilize these traits to explain and predict zooplankton community structure and dynamics under different environmental conditions, including global change scenarios......Zooplankton are major primary consumers and predators in most aquatic ecosystems. They exhibit tremendous diversity of traits, ecological strategies and, consequently, impacts on other trophic levels and the cycling of materials and energy. An adequate representation of this diversity in community...

  12. Response of zooplankton to physical changes in the environment: coastal upwelling along central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Nair, S.R.S.; Haridas, P.; Padmavati, G.

    .U. Haq and J.D. Milliman, (Eds.), Marine Geology and Oceanography ofArabian Sea and Coastal Pakistan. New York: Reinhold, pp. 339-350. PAFFENHOFER, G-A.; WESTER, B.T. and NICHO· LAS, W.O., 1984. Zooplankton abundance in rela- Journal of Coastal Research... Ocean. Proceedings of the Indian Academy of Sciences, 94, 129-137. SMITH, S.L., 1982. The northwest Indian Ocean dur ing the monsoons of 1979: distribution, abundance and feeding of zooplankton. Deep-Sea Research, 29, 1331-1353. SMITH, S.L.; BOYQ, C...

  13. Potential zooplankton preys (Copepoda and Appendicularia for Engraulis anchoita in relation to early larval and spawning distributions in the Patagonian frontal system (SW Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Mariela L. Spinelli

    2011-11-01

    Full Text Available We investigated the spatial distribution of the abundance, biomass and size of zooplankton (nauplii, calanoids, cyclopoids and appendicularians in relation to the distribution of first-feeding larvae and eggs of Engraulis anchoita across the frontal system of Peninsula Valdés. Twelve samples of zooplankton and ichthyoplankton were taken with small Bongo (67 μm and Pairovet (200 μm nets during the spring of 2004 along two transects. The total abundance of zooplankton and the chlorophyll a concentration were higher in homogeneous waters, while total biomasses were higher in stratified waters. Temperature was negatively correlated with biological variables and was the main factor affecting the zooplankton distribution. In both transects, abundance peaks of first-feeding larvae were detected at coastal stations along with the smallest fraction of zooplankton ( < 500 μm, while the largest fraction was dominant at the external stations, coinciding with the highest egg abundance. The physical structure of this front generates different levels of food availability for first-feeding larvae. Calanoids (southern transect and cyclopoids (northern transect are predominant followed by nauplii and appendicularians. The biomass of zooplankton preys contributes to the carbon transfer to the upper trophic levels and is probably important for the survival and growth of anchovy larvae in this frontal system.

  14. Zooplankton Distribution and Species Composition Along an Oxygen Gradient in Puget Sound, WA

    Science.gov (United States)

    Keister, J. E.; Essington, T.; Li, L.; Horne, J. K.; Sato, M.; Parker-Stetter, S. L.; Moriarty, P.

    2016-02-01

    Low dissolved oxygen (hypoxia) is one of the most pronounced, pervasive, and significant disturbances in marine ecosystems, yet our understanding of its effects is incomplete, particularly with respect to impacts on lower trophic levels. As part of a study of how hypoxia affects predator-prey relationships and energy flow through marine food webs, we are studying relationships between ocean chemistry and zooplankton in Puget Sound, Washington—a deep, seasonally hypoxic fjord in the Pacific Northwest that supports a productive and diverse pelagic community. From summer through fall in two years that differed in the timing and intensity of hypoxia, we conducted multi-frequency bioacoustic surveys, CTD casts, and depth-stratified zooplankton sampling to examine changes in distribution and species composition of animals in relation to oxygen concentrations. We exploited a natural gradient in oxygen along the axis of the fjord by sampling at moderately hypoxic and normoxic sites with otherwise similar hydrography and species composition to disentangle the effects of oxygen from changes in other environmental factors. Our results support the hypothesis that zooplankton species composition and vertical distributions are altered by hypoxia, but only when examined at the species and life-stage level. Relatively few taxa showed clear responses to hypoxia, and bioacoustic backscatter data (which was dominated by adult euphausiids and amphipods) indicated that those taxa were not affected by the levels of hypoxia we observed. Examination of net tow data revealed more subtle changes, including behavioral avoidance of low oxygen by some copepods and young euphausiid life stages. Overall, the high species diversity and relatively low susceptibility of many zooplankton to hypoxia in Puget Sound may confer ecosystem resilience to near-future projected changes in this region.

  15. Effects of natural banks of free-floating plants on zooplankton community in a shallow subtropical lake in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Vanessa Gazulha

    2011-08-01

    Full Text Available The aim of this study was to test the effects of natural free-floating plants on zooplankton distribution in a shallow subtropical lake. First, the hypothesis that free-floating plants have an effect on physico-chemicals, leading to a decrease on nutrient availability and influencing the phytoplankton biomass and zooplankton community was tested. Second, the hypothesis that free-floating plants act as a refuge for zooplankton was tested. Three microhabitats were selected: free-floating plants, littoral area and open water. Results demonstrated that the effects of different microhabitats on phytoplankton biomass and physico-chemicals were not significant, indicating a weak influence of the plants. Zooplankton densities were higher in free-floating plants and littoral area, although the effect of microhabitats was weak for most of the predominant genera. The absence of free-floating plant effects on phytoplankton and physico-chemicals showed that it was not a factor influencing the microcrustacean distribution in the microhabitats. Low differences in densities of zooplankton among microhabitats and low abundance of large-bodied cladocerans led to reject the hypothesis that free-floating plants act as a refuge for zooplankton.

  16. Comparisons between POC and zooplankton swimmer flux from sediment traps in the subarctic and subtropical North Pacific

    Science.gov (United States)

    Yokoi, Naoya; Abe, Yoshiyuki; Kitamura, Minoru; Honda, Makio C.; Yamaguchi, Atsushi

    2018-03-01

    Seasonal changes in zooplankton swimmer (ZS) abundance, biomass and community structure were evaluated based on samples collected by moored sediment traps at a depth of 200 m in the subarctic (SA) and subtropical (ST) western North Pacific. Based on these samples, we made comparisons on two topics: 1) latitudinal (subarctic vs. subtropical) changes in ZS abundance, biomass and community and 2) quantitative differences between the ZS and particle organic carbon (POC) fluxes based on data from moored or drifting sediment traps. The results showed that the ZS flux was greater in the SA (annual mean: 311 ind. m-2 day-1 or 258 mg C m-2 day-1) than in the ST (135 ind. m-2 day-1 or 38 mg C m-2 day-1). The peak ZS flux was observed from July-August in the SA and from April-May in the ST. The dominant taxa were Copepoda and Chaetognatha in the SA and Ostracoda and Mollusca in the ST. These latitudinal differences are likely related to the dominance of large-sized Copepoda in the SA, regional differences in the timing of the spring phytoplankton bloom, and the magnitude and size structure of primary producers. The percent composition of ZS to the total C flux (= ZS+POC flux) varied by region: 85-95% in the SA and 47-75% in the ST. These differences between the ZS composition and the total C flux are most likely caused by the dominance of large-sized Copepoda (Neocalanus spp. and Eucalanus bungii) in the SA.

  17. Synchronous dynamics of zooplankton competitors prevail in temperate lake ecosystems.

    Science.gov (United States)

    Vasseur, David A; Fox, Jeremy W; Gonzalez, Andrew; Adrian, Rita; Beisner, Beatrix E; Helmus, Matthew R; Johnson, Catherine; Kratina, Pavel; Kremer, Colin; de Mazancourt, Claire; Miller, Elizabeth; Nelson, William A; Paterson, Michael; Rusak, James A; Shurin, Jonathan B; Steiner, Christopher F

    2014-08-07

    Although competing species are expected to exhibit compensatory dynamics (negative temporal covariation), empirical work has demonstrated that competitive communities often exhibit synchronous dynamics (positive temporal covariation). This has led to the suggestion that environmental forcing dominates species dynamics; however, synchronous and compensatory dynamics may appear at different length scales and/or at different times, making it challenging to identify their relative importance. We compiled 58 long-term datasets of zooplankton abundance in north-temperate and sub-tropical lakes and used wavelet analysis to quantify general patterns in the times and scales at which synchronous/compensatory dynamics dominated zooplankton communities in different regions and across the entire dataset. Synchronous dynamics were far more prevalent at all scales and times and were ubiquitous at the annual scale. Although we found compensatory dynamics in approximately 14% of all combinations of time period/scale/lake, there were no consistent scales or time periods during which compensatory dynamics were apparent across different regions. Our results suggest that the processes driving compensatory dynamics may be local in their extent, while those generating synchronous dynamics operate at much larger scales. This highlights an important gap in our understanding of the interaction between environmental and biotic forces that structure communities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Impacts of zooplankton composition and algal enrichment on the accumulation of mercury in an experimental freshwater food web

    Energy Technology Data Exchange (ETDEWEB)

    Pickhardt, Paul C. [Department of Biological Sciences, Dartmouth College, Hanover, NH 03755 (United States)]. E-mail: paul.pickhardt@stonybrook.edu; Folt, Carol L. [Department of Biological Sciences, Dartmouth College, Hanover, NH 03755 (United States); Chen, Celia Y. [Department of Biological Sciences, Dartmouth College, Hanover, NH 03755 (United States); Klaue, Bjoern [Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Blum, Joel D. [Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)

    2005-03-01

    There is a well documented accumulation of mercury in fish to concentrations of concern for human consumption. Variation in fish Hg burden between lakes is often high and may result from differences in Hg transfer through lower levels of the food web where mercury is bioconcentrated to phytoplankton and transferred to herbivorous zooplankton. Prior research derived patterns of mercury accumulation in freshwater invertebrates from field collected animals. This study provides results from controlled mesocosm experiments comparing the effects of zooplankton composition, algal abundance, and the chemical speciation of mercury on the ability of zooplankton to accumulate mercury from phytoplankton and transfer that mercury to planktivores. Experiments were conducted in 550-L mesocosms across a gradient of algal densities manipulated by inorganic nutrient additions. Enriched, stable isotopes of organic (CH{sub 3} {sup 200}HgCl) and inorganic ({sup 201}HgCl{sub 2}) mercury were added to mesocosms and their concentrations measured in water, seston, and three common zooplankton species. After 2 weeks, monomethylmercury (MMHg) concentrations were two to three times lower in the two copepod species, Leptodiaptomus minutus and Mesocyclops edax than in the cladoceran, Daphnia mendotae. All three zooplankton species had higher MMHg concentrations in mesocosms with low versus high initial algal abundance. However, despite higher concentrations of inorganic mercury (Hg{sub I}) in seston from low nutrient mesocosms, there were no significant differences in the Hg{sub I} accumulated by zooplankton across nutrient treatments. Bioaccumulation factors for MMHg in the plankton were similar to those calculated for plankton in natural lakes and a four-compartment (aqueous, seston, macrozooplankton, and periphyton/sediments) mass balance model after 21 days accounted for {approx}18% of the CH{sub 3} {sup 200}Hg and {approx}33% of the {sup 201}Hg added. Results from our experiments

  19. Impacts of zooplankton composition and algal enrichment on the accumulation of mercury in an experimental freshwater food web

    International Nuclear Information System (INIS)

    Pickhardt, Paul C.; Folt, Carol L.; Chen, Celia Y.; Klaue, Bjoern; Blum, Joel D.

    2005-01-01

    There is a well documented accumulation of mercury in fish to concentrations of concern for human consumption. Variation in fish Hg burden between lakes is often high and may result from differences in Hg transfer through lower levels of the food web where mercury is bioconcentrated to phytoplankton and transferred to herbivorous zooplankton. Prior research derived patterns of mercury accumulation in freshwater invertebrates from field collected animals. This study provides results from controlled mesocosm experiments comparing the effects of zooplankton composition, algal abundance, and the chemical speciation of mercury on the ability of zooplankton to accumulate mercury from phytoplankton and transfer that mercury to planktivores. Experiments were conducted in 550-L mesocosms across a gradient of algal densities manipulated by inorganic nutrient additions. Enriched, stable isotopes of organic (CH 3 200 HgCl) and inorganic ( 201 HgCl 2 ) mercury were added to mesocosms and their concentrations measured in water, seston, and three common zooplankton species. After 2 weeks, monomethylmercury (MMHg) concentrations were two to three times lower in the two copepod species, Leptodiaptomus minutus and Mesocyclops edax than in the cladoceran, Daphnia mendotae. All three zooplankton species had higher MMHg concentrations in mesocosms with low versus high initial algal abundance. However, despite higher concentrations of inorganic mercury (Hg I ) in seston from low nutrient mesocosms, there were no significant differences in the Hg I accumulated by zooplankton across nutrient treatments. Bioaccumulation factors for MMHg in the plankton were similar to those calculated for plankton in natural lakes and a four-compartment (aqueous, seston, macrozooplankton, and periphyton/sediments) mass balance model after 21 days accounted for ∼18% of the CH 3 200 Hg and ∼33% of the 201 Hg added. Results from our experiments corroborate results from field studies and suggest the

  20. Biomass relations between phytoplankton and zooplankton in Goa waters

    Digital Repository Service at National Institute of Oceanography (India)

    Pant, A.; Matondkar, S.G.P.; Goswami, S.C.

    Biomass of phytoplankton and zooplankton, measured as particulate oxidizable carbon, shows that at shallowest stations (5 m) there is large excess of phytoplankton organic carbon over zooplankton carbon in all the samples There is no significant...

  1. Aging of microplastics promotes their ingestion by marine zooplankton.

    Science.gov (United States)

    Vroom, Renske J E; Koelmans, Albert A; Besseling, Ellen; Halsband, Claudia

    2017-12-01

    Microplastics (microplastics to test their impacts, while aging processes such as weathering and biofouling alter the characteristics of plastic particles in the marine environment. We investigated zooplankton ingestion of polystyrene beads (15 and 30 μm) and fragments (≤30 μm), and tested the hypothesis that microplastics previously exposed to marine conditions (aged) are ingested at higher rates than pristine microplastics. Polystyrene beads were aged by soaking in natural local seawater for three weeks. Three zooplankton taxa ingested microplastics, excluding the copepod Pseudocalanus spp., but the proportions of individuals ingesting plastic and the number of particles ingested were taxon and life stage specific and dependent on plastic size. All stages of Calanus finmarchicus ingested polystyrene fragments. Aged microbeads were preferred over pristine ones by females of Acartia longiremis as well as juvenile copepodites CV and adults of Calanus finmarchicus. The preference for aged microplastics may be attributed to the formation of a biofilm. Such a coating, made up of natural microbes, may contain similar prey as the copepods feed on in the water column and secrete chemical exudates that aid chemodetection and thus increase the attractiveness of the particles as food items. Much of the ingested plastic was, however, egested within a short time period (2-4 h) and the survival of adult Calanus females was not affected in an 11-day exposure. Negative effects of microplastics ingestion were thus limited. Our findings emphasize, however, that aging plays an important role in the transformation of microplastics at sea and ingestion by grazers, and should thus be considered in future microplastics ingestion studies and estimates of microplastics transfer into the marine food web. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Changes of species composition, formation of quantitative structure and peculiarities of development of proto- and meta zooplankton under the impact of ecological factors in Lake Drukshiai

    International Nuclear Information System (INIS)

    Mazheikaite, S.

    1997-01-01

    According to 1993-95 research data, water temperature was found to be the most significant factor influencing the structure of zooplankton as well as seasonal development changes. Because of great amount of heated water discharged from Ignalina NPP, determining an increase of the temperature in all water layers and disappearance of the thermal zone below 10 degrees of Centigrade in deep water layers in summer, the species diversity of zooplankton decreased more than twice if compared with 1979-86. Cold-steno thermal species were the first to disappear. At the same time, warm-requiring and eurithermal species predominated. Natural seasonal rise of temperature (till 26.5 degrees of Centigrade) stimulated the development of some groups of meta zooplankton (Cladocera and Copepod a). The abundance of most species of Rotator ia decreased when the water temperature was over 15 degrees of Centigrade. The heated water discharged from Ignalina NPP caused structural changes of meta zooplankton, decrease of its biomass, decrease of the amount and biomass of proto zooplankton in this area. Because of heated water impact, the highest mortality of proto zooplankton was observed in summer. One maximum of quantitative development was characteristic of seasonal dynamics of zooplankton in Lake Drukshiai, while in water basins with natural thermal regime there are 2 seasonal maxima. Dependence of proto zooplankton on phytoplankton nd on Copepod a as well as dependence of meta zooplankton on phytoplankton were investigated. Data on spatial distribution of zooplankton in Lake Drukshiai indicate the eutrophication process in the southwestern part of the lake (because of increase of biogen s concentration). (author)

  3. The effects of environmental parameters on zooplankton assemblages in tropical coastal estuary, South-west, Nigeria

    Directory of Open Access Journals (Sweden)

    Waidi O. Abdul

    2016-09-01

    Full Text Available The present study was carried out to examine the distribution and assemblage structure of zooplankton in relation to environmental parameters of tropical coastal estuarine ecosystem impounding Bight of Benin, Nigeria. The estuarine water samples were collected between January and December, 2014 from three sampling zones (Brushpark, Open water and Wetland then were fixed in 4% formalin. A total of twenty-eight (28 species belonging to four (4 groups were recorded in this study. These groups were rotifera, copepoda, cladocerans and ostracodas, and were all widely distributed in the three investigated zones. Higher richness, dominance and abundance indices were recorded in Zone I when compared to both Zones II and III. Cluster analysis showed five distinct species communities. The canonical correspondence analysis (CCA showed a distinct smattering positive and negative correlation on the distribution of zooplankton indicating that the relative abundance of any species was dependent on specific environmental variables.

  4. Analysis of southeast Australian zooplankton observations of 1938-42 using synoptic oceanographic conditions

    Science.gov (United States)

    Baird, Mark E.; Everett, Jason D.; Suthers, Iain M.

    2011-03-01

    The research vessel Warreen obtained 1742 planktonic samples along the continental shelf and slope of southeast Australia from 1938-42, representing the earliest spatially and temporally resolved zooplankton data from Australian marine waters. In this paper, Warreen observations along the southeast Australian seaboard from 28°S to 38°S are interpreted based on synoptic meteorological and oceanographic conditions and ocean climatologies. Meteorological conditions are based on the NOAA-CIRES 20th Century Reanalysis Project; oceanographic conditions use Warreen hydrological observations, and the ocean climatology is the CSIRO Atlas of Regional Seas. The Warreen observations were undertaken in waters on average 0.45 °C cooler than the climatological average, and included the longest duration El Niño of the 20th century. In northern New South Wales (NSW), week time-scale events dominate zooplankton response. In August 1940 an unusual winter upwelling event occurred in northern NSW driven by a stronger than average East Australian Current (EAC) and anomalous northerly winds that resulted in high salp and larvacean abundance. In January 1941 a strong upwelling event between 28° and 33°S resulted in a filament of upwelled water being advected south and alongshore, which was low in zooplankton biovolume. In southern NSW a seasonal cycle in physical and planktonic characteristics is observed. In January 1941 the poleward extension of the EAC was strong, advecting more tropical tunicate species southward. Zooplankton abundance and distribution on the continental shelf and slope are more dependent on weekly to monthly timescales on local oceanographic and meteorological conditions than continental-scale interannual trends. The interpretation of historical zooplankton observations of the waters off southeast Australia for the purpose of quantifying anthropogenic impacts will be improved with the use of regional hindcasts of synoptic ocean and atmospheric weather that can

  5. Zooplankton biomass and production in the North Sea during the Autumn Circulation experiment, October 1987–March 1988

    DEFF Research Database (Denmark)

    Hay, S.J.; Kiørboe, Thomas; Matthews, A.

    1991-01-01

    Distribution and abundance of zooplankton in the North Sea during the Autumn Circulation Experiment (October 1987–March 1988) were examined. From shipboard egg production incubations and the distributions of eggs, nauplii and females, the productivity of various copepod species was described. Aga...

  6. Current status of zooplankton in reservoir R-3 of the 'Mayak' production association

    Energy Technology Data Exchange (ETDEWEB)

    Osipova, O.; Pryakhin, E. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Ivanov, I. [FSUE Mayak PA (Russian Federation)

    2014-07-01

    One of the commonly used objects for the study of human influence on aquatic ecosystems is zooplankton. Zooplankton community is a sensitive component of biota in reservoir which can change their functional parameters and species composition in response to exposure to different factors. The role of zooplankton in the transformation of energy and in the biotic cycling of the substance is very important. The study of the responses of this element in the water ecosystem with anthropogenic influences, including radioactive contamination, is an important task. The object of the study was the zooplankton in the reservoir R-3, Chelyabinsk region, Russia. R-3 is located in the buffer zone of the 'Mayak' PA and is the storage for low-level radioactive waste. In addition to the high content of radionuclides (the average specific activity of {sup 90}Sr in water was 2.8 kBq/l, {sup 137}Cs - 0.7 kBq/l), this reservoir is characterized by high values of dichromate oxidizability and phosphate contamination. Previously, the study of the zooplankton of this reservoir was conducted in 1952, regular observations were not organized. Assessment of the current status of the community, more than half a century residing in the conditions of radioactive and chemical contamination, seems highly interesting. Sampling was carried out in 2011-2012 at three stations: in the upper, middle, and near the dam of the reservoir by the method of weighted average of samples with bathometer. Analysis of samples showed that the zooplankton community consists of the following major groups: rotifers and cladocerans and copepods crustaceans. In total in R-3 27 species of zooplankton, including 19 species of rotifers, 3 species of copepod and 3 species of cladocerans, as well as two species of ciliates were discovered. Zooplankton abundance in 2011 was 9±9 million individuals/m{sup 3} (given the mean and standard deviation), in 2012 - 26.0±0.9 million individuals/m{sup 3}. The main contribution

  7. Zooplankton biomass to chlorophyll ratios in relation to trophic status ...

    African Journals Online (AJOL)

    Rising eutrophication in South African reservoirs is of major concern, leading to the consideration of top-down biomanipulation as a management option – reducing zooplankton-eating fish to sustain zooplankton grazing pressure and thus restrict autotrophic plankton that proliferate with nutrient increases. The biomass ratio ...

  8. A new modelling approach for zooplankton behaviour

    Science.gov (United States)

    Keiyu, A. Y.; Yamazaki, H.; Strickler, J. R.

    We have developed a new simulation technique to model zooplankton behaviour. The approach utilizes neither the conventional artificial intelligence nor neural network methods. We have designed an adaptive behaviour network, which is similar to BEER [(1990) Intelligence as an adaptive behaviour: an experiment in computational neuroethology, Academic Press], based on observational studies of zooplankton behaviour. The proposed method is compared with non- "intelligent" models—random walk and correlated walk models—as well as observed behaviour in a laboratory tank. Although the network is simple, the model exhibits rich behavioural patterns similar to live copepods.

  9. Carbon export by vertically migrating zooplankton

    DEFF Research Database (Denmark)

    Hansen, Agnethe Nøhr; Visser, André W.

    2016-01-01

    Through diel vertical migration (DVM), zooplankton add an active transport to the otherwise passive sinking of detrital material that constitutes the biological pump. This active transport has proven difficult to quantify. We present a model that estimates both the temporal and depth characterist...... is transported than at either equatorial or boreal latitudes. We estimate that the amount of carbon transported below the mixed layer by migrating zooplankton in the North Atlantic Ocean constitutes 27% (16–30%) of the total export flux associated with the biological pump in that region...

  10. The concentration of 137Cs and stable Cs in zooplankton in the western North Pacific in relation to their taxonomic composition

    International Nuclear Information System (INIS)

    Kaeriyama, Hideki; Watabe, Teruhisa; Kusakabe, Masashi

    2008-01-01

    The objective of this study is to obtain information on the background level of 137 Cs in zooplankton in the waters close to Rokkasho-mura in Aomori Prefecture, Japan, where a large-scale project has been progressively promoted to establish the nuclear fuel cycle. Prior to the full-scale operation of the spent nuclear fuel reprocessing plant, zooplankton samples were collected in May and October 2005, June 2006, and June 2007 from the surface water (0-5 m depth). The samples were analyzed to determine the concentrations of 137 Cs and stable Cs in relation to taxonomic composition. The numerical abundance of the plankton varied from 253 to 1514 inds. m -3 . Taxonomic composition differed between the two sampling periods. Although copepods formed the most abundant taxonomic group during both seasons, gelatinous plankton (chaetognaths, siphonophores, appendicularians and doliolids) were more abundant in October 2005 than in June 2006 and June 2007. The concentration of 137 Cs in zooplankton varied from 11 to 24 mBq kg-WW -1 . At the same station, the 137 Cs concentration in zooplankton in October 2005 was almost twice as much as that in June 2006, although the concentration of 137 Cs in seawater did not show a difference. The concentration of stable Cs was measured for each taxonomic group: that in gelatinous zooplankton (chaetognaths) was higher than that in crustacean zooplankton (copepods, euphausiids and amphipods). These results suggest that the concentration of 137 Cs in zooplankton is affected by the occurrence of gelatinous zooplankton. (author)

  11. Effects of sandbar openings on the zooplankton community of coastal lagoons with different conservation status

    Directory of Open Access Journals (Sweden)

    Rayanne Barros Setubal

    Full Text Available AIM: Artificial sandbar openings are a common management practice in coastal lagoons but they can be a threat when negative effects to the quality of water and to the aquatic biota are observed. The current study compared sandbar opening effects in two coastal lagoons located close to each other, but differing on trophic status and on sandbar openings' background. METHODS:Limnological variables and zooplankton community were recorded monthly during one year before and one year after sandbar openings that occurred in the same month for both lagoons, giving 24 samples. We compared the effects of sandbar opening on response variables, according to the two types of system. RESULTS: The sandbar openings determined changes in some limnological features - depth and salinity - but such effects were different in the two types of system. The zooplankton structure displayed dramatic changes in the eutrophic and commonly opened lagoon. The occurrence and abundance of some species were closely related to changes in limnological variables. CONCLUSIONS: Our data indicated that zooplankton communities are more resistant to sandbar openings in coastal lagoons historically less disturbed. The direction and magnitude of changes promoted by sandbar openings might be specific to each lagoon, due to different backgrounds of disturbances that, in the long term, modify the water quality and the structure of zooplankton communities, and consequently, their resistance and resilience.

  12. Zooplankton grazing in a eutrophic lake: implications of diel vertical migration

    International Nuclear Information System (INIS)

    Lampert, W.; Taylor, B.E.

    1985-01-01

    During summer and fall, depth profiles of zooplankton community grazing were determined in situ during day and night in the Schoehsee, a small eutrophic lake. Labeled algae of two different sizes were mixed with the natural suspension of phytoplankton in a grazing chamber. A small blue-green alga (Synechococcus, 1 μm) was labeled with 32 P; a larger green alga (Scenedesmus, 4-15 μm) was labeled with 14 C. During summer, grazing in the upper 5 m was negligible during day but strong at night. Hence, algae grow relatively unimpeded by grazing during daytime but are harvested at night. Vertical and diel differences in grazing rates disappeared when the vertical migration ceased in fall. Selectivity of grazing was controlled by the zooplankton species composition. Eudiaptomus showed a strong preference for Scenedesmus. Daphnia showed a slight preference for Scenedesmus, but Ceriodaphnia preferred Synechococcus. Cyclopoid copepodites did not ingest the small blue-green. Because Daphnia and Eudiaptomus were dominant, grazing rates on larger cells were usually higher than grazing rates on the small cells. Negative electivity indices for scenedesmus occurred only when the biomass of large crustaceans was extremely low (near the surface, during day). Zooplankton biomass was the main factor controlling both vertical and seasonal variations in grazing. Highest grazing rates (65%/d) were measured during fall when zooplankton abundance was high. Because differential losses can produce substantial errors in the results, it was necessary to process the samples on the boat immediately after collection, without preservation

  13. Determine Age-structure of Gelatinous Zooplankton Using Optical Coherence Tomography

    Science.gov (United States)

    Bi, H.; Shahrestani, S.; He, Y.

    2016-02-01

    Gelatinous are delicate and transparent by nature, but are conspicuous in many ecosystems when in bloom. Their proliferations are a bothersome and costly nuisance and influencing important food webs and species interactions. More importantly, gelatinous zooplankton respond to climate change rapidly and understanding their upsurge needs information on their recruitment and population dynamics which in turn require their age-structure. However, ageing gelatinous zooplankton is often restricted by the fact that they shrink under unfavorable conditions. In the present study, we examine the potential of using optical coherence tomography (OCT) to age gelatinous zooplankton. OCT is a non-invasive imaging technique that uses light waves to examine 2D or 3D structure of target objects at a resolution of 3-5 µm. We were able to successfully capture both 3D and 2D images of sea nettle muscle fibers. Preliminary results on ctenophores will be discussed. Overall, this non-destructive sampling allows us to scan and capture images of mesoglea from jellyfish cultured in the lab, using the same individual repeatedly through time, documenting its growth which will provide precise measurements to construct an age key that will be applied to gelatinous zooplankton captured in the field. Coupled with information on abundance, we can start to quantify their recruitment timing and success rate.

  14. About the scientific names of paraphyletic taxa

    OpenAIRE

    TIMM, Tarmo

    2012-01-01

    The 'naturality' of monophyletic taxa in comparison with that of paraphyletic ones is discussed, with examples from Clitellata. Regular scientific names for paraphyletic taxa are inevitable in a workable biological classification.

  15. Migrant biomass and respiratory carbon flux by zooplankton and micronekton in the subtropical northeast Atlantic Ocean (Canary Islands)

    Science.gov (United States)

    Ariza, A.; Garijo, J. C.; Landeira, J. M.; Bordes, F.; Hernández-León, S.

    2015-05-01

    Diel Vertical Migration (DVM) in marine ecosystems is performed by zooplankton and micronekton, promoting a poorly accounted export of carbon to the deep ocean. Major efforts have been made to estimate carbon export due to gravitational flux and to a lesser extent, to migrant zooplankton. However, migratory flux by micronekton has been largely neglected in this context, due to its time-consuming and difficult sampling. In this paper, we evaluated gravitational and migratory flux due to the respiration of zooplankton and micronekton in the northeast subtropical Atlantic Ocean (Canary Islands). Migratory flux was addressed by calculating the biomass of migrating components and measuring the electron transfer system (ETS) activity in zooplankton and dominant species representing micronekton (Euphausia gibboides, Sergia splendens and Lobianchia dofleini). Our results showed similar biomass in both components. The main taxa contributing to DVM within zooplankton were juvenile euphausiids, whereas micronekton were mainly dominated by fish, followed by adult euphausiids and decapods. The contribution to respiratory flux of zooplankton (3.4 ± 1.9 mg C m-2 d-1) was similar to that of micronekton (2.9 ± 1.0 mg C m-2 d-1). In summary, respiratory flux accounted for 53% (range 23-71) of the gravitational flux measured at 150 m depth (11.9 ± 5.8 mg C m-2 d-1). However, based on larger migratory ranges and gut clearance rates, micronekton are expected to be the dominant component that contributes to carbon export in deeper waters. Micronekton estimates in this paper as well as those in existing literature, although variable due to regional differences and difficulties in calculating their biomass, suggest that carbon fluxes driven by this community are important for future models of the biological carbon pump.

  16. Mixture of commercial herbicides based on 2,4-D and glyphosate mixture can suppress the emergence of zooplankton from sediments.

    Science.gov (United States)

    Portinho, Jorge L; Nielsen, Daryl L; Daré, Luana; Henry, Raoul; Oliveira, Régis C; Branco, Ciro C Z

    2018-07-01

    It is generally assumed that zooplankton can recolonize lakes that have been exposed to pesticides, via their dormant egg banks. Hitherto, few studies have evaluated the relative importance of dormant egg bank recruitment in the re-establishment of zooplankton communities in the presence of pesticide. This study investigated the effects of commercial products Bratt ® (a.i. 2,4-D), Roundup ® (a.i. glyphosate) and their mixture on the emergence (abundance and taxon richness) of dormant zooplankton egg banks from natural lake sediment. Sediment samples were collected from the surface sediment (commercial products Bratt ® , Roundup ® and their mixture can suppress the emergence of rotifers, thereby influencing zooplankton recruitment potential in lakes impacted by the presence of these commercial herbicides. Our results stress the importance of the need for additional studies to assess the effects of pesticides on dormant egg banks. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Latitudinal environmental gradients and diel variability influence abundance and community structure of Chaetognatha in Red Sea coral reefs

    KAUST Repository

    Al-aidaroos, Ali M.

    2016-08-15

    The Red Sea has been recognized as a unique region to study the effects of ecohydrographic gradients at a basin-wide scale. Its gradient of temperature and salinity relates to the Indian Ocean monsoon and associated wind-driven transport of fertile and plankton-rich water in winter from the Gulf of Aden into the Red Sea. Subsequent evaporation and thermohaline circulation increase the salinity and decrease water temperatures toward the North. Compared with other ocean systems, however, relatively little is known about the zooplankton biodiversity of the Red Sea and how this relates to Red Sea latitudinal gradients. Among the most abundant zooplankton taxa are Chaetognatha, which play an important role as secondary consumers in most marine food webs. Since Chaetognatha are sensitive to changes in temperature and salinity, we surmised latitudinal changes in their biodiversity, community structure and diel variability along the coast of Saudi Arabia. Samples were collected at nine coral reefs spanning approximately 1500km, from the Gulf of Aqaba in the northern Red Sea to the Farasan Archipelago in the southern Red Sea. Thirteen Chaetognatha species belonging to two families (Sagittidae and Krohnittidae) were identified. Latitudinal environmental changes and availability of prey (i.e. Copepoda, Crustacea) altered Chaetognatha density and distribution. The cosmopolitan epiplanktonic Flaccisagitta enflata (38.1%) dominated the Chaetognatha community, and its abundance gradually decreased from South to North. Notable were two mesopelagic species (Decipisagitta decipiens and Caecosagitta macrocephala) in the near-reef surface mixed layers at some sites. This was related to wind-induced upwelling of deep water into the coral reefs providing evidence of trophic oceanic subsidies. Most Sagittidae occurred in higher abundances at night, whereas Krohnittidae were more present during the day. Chaetognatha with developing (stage II) or mature ovaries (stage III) were more active

  18. Article Review: Lessepsian migration of zooplankton through Suez Canal and its impact on ecological system

    Directory of Open Access Journals (Sweden)

    Howaida Y. Zakaria

    2015-01-01

    Full Text Available The marine environment of the East Mediterranean has been considerably impacted in modern times by two man-made changes: the creation of a waterway between the Indo-Pacific and the Mediterranean basins and the control of the Nile fresh-water outflow. The opening of the Suez Canal caused a migration generally from the Red Sea to the Mediterranean, and rarely in the opposite direction as the Red Sea is generally saltier and more nutrient-poor than the Atlantic, so the Red Sea species have advantages over Atlantic species in the salty and nutrient-poor eastern Mediterranean. Accordingly Red Sea species invaded the Mediterranean ecosystem and not vice versa; this phenomenon is known as the Lessepsian migration or erythrean invasion. The composition of zooplankton in the eastern Mediterranean has been shown to include a large proportion of Indo-Pacific and other circumtropical species which have successfully settled and proliferated in this environment. During the present study, an overview is provided on zooplankton migration through Suez Canal and its impact on the ecological system based on published literature. It is also meant with the hydrographic and zooplankton characteristics of the adjacent seas. It is clear that, except jellyfish Rhopilema nomadica, the negative impact of zooplankton Lessepsian migratory species in the Egyptian Mediterranean waters is not evident. Finally, it would be concluded that, a continuous monitoring programme will be needed to record the recent erythrean zooplankton species and follow up the distribution and abundance of those previously recorded as aliens to assess their impacts on the native biodiversity of the Mediterranean.

  19. Spatio-temporal variability of the North Sea cod recruitment in relation to temperature and zooplankton.

    Directory of Open Access Journals (Sweden)

    Delphine Nicolas

    Full Text Available The North Sea cod (Gadus morhua, L. stock has continuously declined over the past four decades linked with overfishing and climate change. Changes in stock structure due to overfishing have made the stock largely dependent on its recruitment success, which greatly relies on environmental conditions. Here we focus on the spatio-temporal variability of cod recruitment in an effort to detect changes during the critical early life stages. Using International Bottom Trawl Survey (IBTS data from 1974 to 2011, a major spatio-temporal change in the distribution of cod recruits was identified in the late 1990s, characterized by a pronounced decrease in the central and southeastern North Sea stock. Other minor spatial changes were also recorded in the mid-1980s and early 1990s. We tested whether the observed changes in recruits distribution could be related with direct (i.e. temperature and/or indirect (i.e. changes in the quantity and quality of zooplankton prey effects of climate variability. The analyses were based on spatially-resolved time series, i.e. sea surface temperature (SST from the Hadley Center and zooplankton records from the Continuous Plankton Recorder Survey. We showed that spring SST increase was the main driver for the most recent decrease in cod recruitment. The late 1990s were also characterized by relatively low total zooplankton biomass, particularly of energy-rich zooplankton such as the copepod Calanus finmarchicus, which have further contributed to the decline of North Sea cod recruitment. Long-term spatially-resolved observations were used to produce regional distribution models that could further be used to predict the abundance of North Sea cod recruits based on temperature and zooplankton food availability.

  20. Zooplankton communities in three adjacent softwater lobelia lakes of slightly differentiated morphology and trophic state

    Directory of Open Access Journals (Sweden)

    Kuczyńska-Kippen Natalia

    2017-12-01

    Full Text Available The paper presents the results of an investigation of physical-chemical features of water as well as rotifer and crustacean abundance and diversity measures, relating to the taxonomic richness and species diversity index, in three lobelia lakes differing in trophic status and morphometric features. The main purpose of this study was to establish the diversity of zooplankton communities in the open water area of lobelia lakes, including extracting species common for each lake and also to find environmental predictors which are responsible for the development of zooplankton communities. Despite the fact that the three studied lakes are of the same origin, located in the same vicinity and have generally similar environmental factors, zooplankton community structure revealed a great variation in reference to species diversity (only ca. 20% of the species were common for all lakes and particularly in inhabiting species. Obrowo Lake had the most diverse assemblages of both rotifers and crustaceans compared to Modre and Pomysko lakes. In the taxonomic structure species that are rare for the Polish fauna, such as e.g. Holopedium gibberum and Heterocope appendiculata, occurred. Even though the examined lobelia lakes are ecosystems that undergo varying human-induced impacts, they still remain taxonomically very variable aquatic ecosystems, containing rare species of very high ecological status. The observed symptoms of deterioration of water quality, reflected in the zooplankton biocoenotic features, showed that the best conditions were attributed to Obrowo Lake in comparison with the two remaining lakes – Modre and Pomysko. Total nitrogen and chlorophyll a concentration were decisive for the distribution of zooplankton species in Pomysko and Obrowo lakes, while in case of Modre lake water reactivity and conductivity were of higher impact.

  1. A Principal Component Analysis (PCA Approach to Seasonal and Zooplankton Diversity Relationships in Fishing Grounds of Mannar Gulf, India

    Directory of Open Access Journals (Sweden)

    Selvin J. PITCHAIKANI

    2017-06-01

    Full Text Available Principal component analysis (PCA is a technique used to emphasize variation and bring out strong patterns in a dataset. It is often used to make data easy to explore and visualize. The primary objective of the present study was to record information of zooplankton diversity in a systematic way and to study the variability and relationships among seasons prevailed in Gulf of Mannar. The PCA for the zooplankton seasonal diversity was investigated using the four seasonal datasets to understand the statistical significance among the four seasons. Two different principal components (PC were segregated in all the seasons homogeneously. PCA analyses revealed that Temora turbinata is an opportunistic species and zooplankton diversity was significantly different from season to season and principally, the zooplankton abundance and its dynamics in Gulf of Mannar is structured by seasonal current patterns. The factor loadings of zooplankton for different seasons in Tiruchendur coastal water (GOM is different compared with the Southwest coast of India; particularly, routine and opportunistic species were found within the positive and negative factors. The copepods Acrocalanus gracilis and Acartia erythrea were dominant in summer and Southwest monsoon due to the rainfall and freshwater discharge during the summer season; however, these species were replaced by Temora turbinata during Northeast monsoon season.

  2. Zooplankton diversity across three Red Sea reefs using pyrosequencing

    KAUST Repository

    Pearman, John K.

    2014-07-30

    Coral reefs are considered among the most diverse ecosystems on Earth, yet little is known about the diversity of plankton in the surrounding water column. Moreover, few studies have utilized genomic methods to investigate zooplankton diversity in any habitat. This study investigated the diversity of taxa by sampling 45 stations around three reef systems in the central/southern Red Sea. The diversity of metazoan plankton was investigated by targeting the 18S rRNA gene and clustering OTUs at 97% sequence similarity. A total of 754 and 854 metazoan OTUs were observed in the data set for the 1380F and 1389F primer sets respectively. The phylum Arthropoda dominated both primer sets accounting for ~60% of reads followed by Cnidaria (~20%). Only about 20% of OTUs were shared between all three reef systems and the relation between geographic distance and Jaccard Similarity measures was not significant. Cluster analysis showed that there was no distinct split between reefs and stations from different reefs clustered together both for metazoans as a whole and for the phyla Arthropoda, Cnidaria and Chordata separately. This suggests that distance may not be a determining factor in the taxonomic composition of stations.

  3. Assessment of power-plant effects on zooplankton in the near field

    International Nuclear Information System (INIS)

    Polgar, T.T.; Bongers, L.H.; Krainak, G.M.

    1976-01-01

    With the use of a simple entrainment model that takes into account tidal recirculation, mixing, and once-through kill rate, theoretical expressions are derived for ratios of densities of live organisms at the intake of a power plant to densities in the far field. Experimental data on the abundances of dead and live stages of Eurytemora affinis and Acartia tonsa are used to compare to model results. A study of the entrainment of zooplankton near the intake of the Morgantown power plant and a concurrent study of the distribution of zooplankton in the Potomac River provided the biological data. Physical information was derived from extensive hydrographic measurements. Comparing experimental data with model predictions showed that radical depletions occurred in the naupliar stages near the plant site which cannot be accounted for by cooling-system or delayed entrainment mortalities. These near-field changes are attributed to avoidance reactions and to mortalities in the vicinity of the plant

  4. Structure, seasonal dynamics and distribution of zooplankton in lake Drukshiai in 1994

    International Nuclear Information System (INIS)

    Mazheikaite, S.; Pashkauskas, R.

    1995-01-01

    Investigations on the zooplankton of Lake Drukshiai were carried out in 1994. There were registered 62 taxons of protozoa and 50 taxons of metazoa, and compared with the data of 1979 - 1986 the diversity of species composition decreased 2.1 times. Eurytermic and stenothermic thermophylic species prevailed in the plankton biocenosis. In protozooplankton dominated ciliates of subclasses teolotricha and spirotricha, in metazooplankton -planctonic crustacea (Copopeda and Cladocera). Rotifers (Rotaria) were abundant only in the shallow and heated water outlet area. Seasonal dynamics of protozooplankton indicated one maximum in spring and metazooplankton - in summer. High diferentiation in quantity and biomass of zooplankton in the lake revealed different level of eutrophication of some areas. (author). 7 refs., 5 figs

  5. The response of zooplankton communities to the 2016 extreme hydrological cycle in floodplain lakes connected to the Yangtze River in China.

    Science.gov (United States)

    Zhang, Kun; Xu, Mei; Wu, Qili; Lin, Zhi; Jiang, Fangyuan; Chen, Huan; Zhou, Zhongze

    2018-06-04

    The Huayanghe Lakes play an important role in the Yangtze floodplain in China and had extremely high water levels during the summer of 2016. Monitoring data was collected in an effort to understand the impact of this change on the crustacean zooplankton composition and abundance and the biomass variation in the Huayanghe Lakes between a regular hydrological cycle (RHC) and an extreme hydrological cycle (EHC). The crustacean zooplankton community composition, abundance, and biomass in the floodplain lakes were markedly affected by the water-level disturbance. The number of species was lower in the RHC, but the mean density and biomass decreased from 93.84 ± 13.29 ind./L and 6.11 ± 0.89 mg/L, respectively, in the RHC to 66.62 ± 10.88 ind./L and 1.22 ± 0.26 mg/L, respectively, in the EHC. Pearson correlations and redundancy analyses revealed the environmental factors with the most significant impact on the crustacean zooplankton community differed between the RHC and EHC cycles. Little previous information exists on the zooplankton in these lakes, and the present study provides data on the zooplankton composition, abundance, and biomass, both at baseline and in response to hydrological changes.

  6. Ecology of selected marine communities in Glacier Bay: Zooplankton, forage fish, seabirds and marine mammals

    Science.gov (United States)

    Robards, Martin D.; Drew, Gary S.; Piatt, John F.; Anson, Jennifer Marie; Abookire, Alisa A.; Bodkin, James L.; Hooge, Philip N.; Speckman, Suzann G.

    2003-01-01

    We studied oceanography (including primary production), secondary production, small schooling fish (SSF), and marine bird and mammal predators in Glacier Bay during 1999 and 2000. Results from these field efforts were combined with a review of current literature relating to the Glacier Bay environment. Since the conceptual model developed by Hale and Wright (1979) ‘changes and cycles’ continue to be the underlying theme of the Glacier Bay ecosystem. We found marked seasonality in many of the parameters that we investigated over the two years of research, and here we provide a comprehensive description of the distribution and relative abundance of a wide array of marine biota. Glacier Bay is a tidally mixed estuary that leads into basins, which stratify in summer, with the upper arms behaving as traditional estuaries. The Bay is characterized by renewal and mixing events throughout the year, and markedly higher primary production than in many neighboring southeast Alaska fjords (Hooge and Hooge, 2002). Zooplankton diversity and abundance within the upper 50 meters of the water column in Glacier Bay is similar to communities seen throughout the Gulf of Alaska. Zooplankton in the lower regions of Glacier Bay peak in abundance in late May or early June, as observed at Auke Bay and in the Gulf of Alaska. The key distinction between the lower Bay and other estuaries in the Gulf of Alaska is that a second smaller peak in densities occurs in August. The upper Bay behaved uniformly in temporal trends, peaking in July. Densities had begun to decline in August, but were still more than twice those observed in that region in May. The highest density of zooplankton observed was 17,870 organisms/m3 in Tarr Inlet during July. Trends in zooplankton community abundance and diversity within the lower Bay were distinct from upper-Glacier Bay trends. Whereas the lower Bay is strongly influenced by Gulf of Alaska processes, local processes are the strongest influence in the upper

  7. Acoustic insights into the zooplankton dynamics of the eastern Weddell Sea

    Science.gov (United States)

    Cisewski, Boris; Strass, Volker H.

    2016-05-01

    The success of any efforts to determine the effects of climate change on marine ecosystems depends on understanding in the first instance the natural variations, which contemporarily occur on the interannual and shorter time scales. Here we present results on the environmental controls of zooplankton distribution patterns and behaviour in the eastern Weddell Sea, Southern Ocean. Zooplankton abundance and vertical migration are derived from the mean volume backscattering strength (MVBS) and the vertical velocity measured by moored acoustic Doppler current profilers (ADCPs), which were deployed simultaneously at 64°S, 66.5°S and 69°S along the Greenwich Meridian from February, 2005, until March, 2008. While these time series span a period of full three years they resolve hourly changes. A highly persistent behavioural pattern found at all three mooring locations is the synchronous diel vertical migration (DVM) of two distinct groups of zooplankton that migrate between a deep residence depth during daytime and a shallow depth during nighttime. The DVM was closely coupled to the astronomical daylight cycles. However, while the DVM was symmetric around local noon, the annual modulation of the DVM was clearly asymmetric around winter solstice or summer solstice, respectively, at all three mooring sites. DVM at our observation sites persisted throughout winter, even at the highest latitude exposed to the polar night. Since the magnitude as well as the relative rate of change of illumination is minimal at this time, we propose that the ultimate causes of DVM separated from the light-mediated proximal cue that coordinates it. In all three years, a marked change in the migration behaviour occurred in late spring (late October/early November), when DVM ceased. The complete suspension of DVM after early November is possibly caused by the combination of two factors: (1) increased availability of food in the surface mixed layer provided by the phytoplankton spring bloom, and

  8. Studies on zooplankton from the Arabian sea off the south-central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sumitra-Vijayaraghavan; Selvakumar, R.A.; Rao, T.S.S.

    Zooplankton biomass, composition and biochemical constituents were studied. Estimated average zooplankton biomass was 8.76 ml/100 m super(3). Of the major components constituting the zooplankton biomass, copepods formed the dominant group. Protein...

  9. Zooplankton use of chemodetection to find and eat particles

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2004-01-01

    The ability of raptorial zooplankton to find large particles such as marine aggregates is crucial to their use of the particles as food and to the fate of the particles. Kiorboe & Thygesen (2001) developed a numerical approach to describe particle detection by chemosensory zooplankton. In this pa......The ability of raptorial zooplankton to find large particles such as marine aggregates is crucial to their use of the particles as food and to the fate of the particles. Kiorboe & Thygesen (2001) developed a numerical approach to describe particle detection by chemosensory zooplankton...

  10. Is Recovery of Large-Bodied Zooplankton after Nutrient Loading Reduction Hampered by Climate Warming? A Long-Term Study of Shallow Hypertrophic Lake Søbygaard, Denmark

    Directory of Open Access Journals (Sweden)

    María Florencia Gutierrez

    2016-08-01

    Full Text Available Nutrient fluctuations and climate warming can synergistically affect trophic dynamics in lakes, resulting in enhanced symptoms of eutrophication, thereby potentially counteracting restoration measures. We performed a long-term study (23 years of zooplankton in Danish Lake Søbygaard, which is in recovery after nutrient loading reduction, but now faces the effects of climate warming. We hypothesized that the recovery of large-bodied zooplankton after nutrient loading reduction would be hampered by climate warming through indirect effects on fish size structure. We found a shift in macrozooplankton from initial dominance of Daphnia spp. towards Bosmina spp. as well as a decline in the body size of copepods and an increase in the abundance of nauplii. These changes coincided with the increase in small sized fish as a result of rising water temperature. Despite a reduction in body size, the total biomass of cladocerans increased coinciding with a diminished fish catch per unit effort (CPUE, and likely then an overall reduction in the predation on zooplankton. A cascading effect to phytoplankton was evidenced by enhanced zooplankton:phytoplankton and cladoceran:phytoplankton ratios and a decrease in Chl-a:TP and Chl-a:TN ratios. Our results indicate that climate warming, through changes in the size structure of fish community, has major effects on zooplankton size structure. In Lake Søbygaard, the decline in zooplankton size did not prevent, but modulated, the positive cascading effect on phytoplankton through an expected diminished fish CPUE related to nutrient loading reduction.

  11. The synergetic effects of turbulence and turbidity on the zooplankton community structure in large, shallow Lake Taihu.

    Science.gov (United States)

    Zhou, Jian; Qin, Boqiang; Han, Xiaoxia

    2018-01-01

    Climate change is predicted to influence the heat budget of aquatic ecosystems and, in turn, affect the stability of the water column leading to increased turbulence coupled with enhanced turbidity. However, the synergetic effects of turbulence and turbidity on zooplankton community structure remain to be understood in large, shallow lakes. To determine the possible synergetic effects of these factors on zooplankton communities, a 15-day mesocosm experiment was carried out and tested under four turbulence and turbidity regimes namely control (ɛ = 0, 7.6 ± 4.2 NTU), low (ɛ = 6.01 × 10 -8  m 2  s -3 , 19.4 ± 8.6 NTU), medium (ɛ = 2.95 × 10 -5  m 2  s -3 , 55.2 ± 14.4 NTU), and high (ɛ = 2.39 × 10 -4  m 2  s -3 , 741.6 ± 105.2 NTU) conditions, which were comparable to the natural conditions in Lake Taihu. Results clearly showed the negative effects of turbulence and turbidity on zooplankton survival, which also differed among taxa. Specifically, increased turbulence and turbidity levels influenced the competition among zooplankton species, which resulted to the shift from being large body crustacean-dominated (copepods and cladocerans) to rotifer-dominated community after 3 days. The shift could be associated with the decrease in vulnerability of crustaceans in such environments. Our findings suggested that changes in the level of both turbidity and turbulence in natural aquatic systems would have significant repercussions on the zooplankton communities, which could contribute to the better understanding of community and food web dynamics in lake ecosystems exposed to natural mixing/disturbances.

  12. Latitudinal distribution of zooplankton communities in the Western Pacific along 160°E during summer 2014

    Science.gov (United States)

    Sun, Dong; Wang, Chunsheng

    2017-05-01

    A total of 51 mesozooplankton samples collected with a WP2 net from 0 to 200 m depth along 160°E (4°S-46°N) in the Western Pacific from June to July 2014 were analyzed. The latitudinal distribution of mesozooplankton community structure was analyzed. The average biomass and abundance in different provinces generally increased with latitude: the biomass of zooplankton ranged from 1.18 mg DW m- 3 (11°N) to 97.81 mg DW m- 3 (45°N), and the abundance of zooplankton ranged from 45.11 ind. m- 3 (3°S) to 439.84 ind. m- 3 (41°N). The community structure of zooplankton also showed a significant latitudinal variation. At lower latitudes, calanoid copepods were the most abundant group, while cyclopoid copepods were the most abundant group at higher latitudes. Multidimensional scaling analysis of community structure and other physical/chemical/biological characteristics supported five ecological provinces in the northwestern Pacific: the Western Pacific Warm Pool Province (WARM), the North Pacific Tropical Gyre (NPTG), the North Pacific Subtropical Gyre (NPST), the Kuroshio Current Province (KURO) and the Pacific Subarctic Gyres Province (PSAG). The Kuroshio Current Province can be regarded as a transitional zone between the subarctic and northern subtropical area, and this transitional zone corresponds much more closely to the ecocline concept, rather than the ecotone concept.

  13. Early Cretaceous greenhouse pumped higher taxa diversification in spiders.

    Science.gov (United States)

    Shao, Lili; Li, Shuqiang

    2018-05-24

    The Cretaceous experienced one of the most remarkable greenhouse periods in geological history. During this time, ecosystem reorganizations significantly impacted the diversification of many groups of organisms. The rise of angiosperms marked a major biome turnover. Notwithstanding, relatively little remains known about how the Cretaceous global ecosystem impacted the evolution of spiders, which constitute one of the most abundant groups of predators. Herein, we evaluate the transcriptomes of 91 taxa representing more than half of the spider families. We add 23 newly sequenced taxa to the existing database to obtain a robust phylogenomic assessment. Phylogenetic reconstructions using different datasets and methods obtain novel placements of some groups, especially in the Synspermiata and the group having a retrolateral tibial apophysis (RTA). Molecular analyses indicate an expansion of the RTA clade at the Early Cretaceous with a hunting predatory strategy shift. Fossil analyses show a 7-fold increase of diversification rate at the same period, but this likely owes to the first occurrences spider in amber deposits. Additional analyses of fossil abundance show an accumulation of spider lineages in the Early Cretaceous. We speculate that the establishment of a warm greenhouse climate pumped the diversification of spiders, in particular among webless forms tracking the abundance of insect prey. Our study offers a new pathway for future investigations of spider phylogeny and diversification. Copyright © 2018. Published by Elsevier Inc.

  14. The Interactive Effect of Multiple Stressors on Crustacean Zooplankton Communities in Montane Lakes

    Science.gov (United States)

    Brittain, Jeffrey T.; Strecker, Angela L.

    2018-02-01

    Nonnative fish introductions have altered thousands of naturally fishless montane lakes, resulting in cascading food web repercussions. Nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of freshwater ecosystems, which may affect the abundance and composition of planktonic communities. This study identified responses of zooplankton communities from two lakes (fish present versus absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance of acidification and eutrophication via nitrogen addition in mesocosms. Zooplankton communities from lakes with different food web structure (i.e., fish present or absent) responded differently to the singular effects of acid and nitrogen addition. For instance, zooplankton biomass decreased in the acid treatment of the fishless lake experiment, but increased in response to acid in the fish-present experiment. In contrast, the combination of acid and nitrogen often resulted in weak responses for both lake types, resulting in nonadditive effects, i.e., the net effect of the stressors was in the opposite direction than predicted, which is known as a reversal or "ecological surprise." This experiment demonstrates the difficulty in predicting the interactive effects of multiple stressors on aquatic communities, which may pose significant challenges for habitat restoration through fish removal.

  15. Fixed-nitrogen loss associated with sinking zooplankton carcasses in a coastal oxygen minimum zone (Golfo Dulce, Costa Rica)

    DEFF Research Database (Denmark)

    Stief, Peter; Lundgaard, Ann Sofie Birch; Morales Ramirez, Alvaro

    2017-01-01

    Oxygen minimum zones (OMZs) in the ocean are of key importance for pelagic fixed-nitrogen loss (N-loss) through microbial denitrification and anaerobic ammonium oxidation (anammox). Recent studies document that zooplankton is surprisingly abundant in and around OMZs and that the microbial community...... associated with carcasses of a large copepod species mediates denitrification. Here, we investigate the complex N-cycling associated with sinking zooplankton carcasses exposed to the steep O2 gradient in a coastal OMZ (Golfo Dulce, Costa Rica). 15N-stable-isotope enrichment experiments revealed...... that the carcasses of abundant copepods and ostracods provide anoxic microbial hotspots in the pelagic zone by hosting intense anaerobic N-cycle activities even in the presence of ambient O2. Carcass-associated anaerobic N-cycling was clearly dominated by dissimilatory nitrate reduction to ammonium (DNRA) at up...

  16. Ecological niches of open ocean phytoplankton taxa

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Vogt, Meike; Payne, Mark

    2015-01-01

    We characterize the realized ecological niches of 133 phytoplankton taxa in the open ocean based on observations from the MAREDAT initiative and a statistical species distribution model (MaxEnt). The models find that the physical conditions (mixed layer depth, temperature, light) govern large...... conditions in the open ocean. Our estimates of the realized niches roughly match the predictions of Reynolds' C-S-R model for the global ocean, namely that taxa classified as nutrient stress tolerant have niches at lower nutrient and higher irradiance conditions than light stress tolerant taxa. Yet...

  17. PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010: 2. Plankton community composition and abundance.

    Science.gov (United States)

    Petitpas, Christian M; Turner, Jefferson T; Deeds, Jonathan R; Keafer, Bruce A; McGillicuddy, Dennis J; Milligan, Peter J; Shue, Vangie; White, Kevin D; Anderson, Donald M

    2014-05-01

    As part of the Gulf of Maine Toxicity (GOMTOX) project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin levels in various plankton size fractions, and the community composition of potential grazers of A. fundyense in plankton size fractions during blooms of this toxic dinoflagellate in the coastal Gulf of Maine and on Georges Bank in spring and summer of 2007, 2008, and 2010. PSP toxins and A. fundyense cells were found throughout the sampled water column (down to 50 m) in the 20-64 μm size fractions. While PSP toxins were widespread throughout all size classes of the zooplankton grazing community, the majority of the toxin was measured in the 20-64 μm size fraction. A. fundyense cellular toxin content estimated from field samples was significantly higher in the coastal Gulf of Maine than on Georges Bank. Most samples containing PSP toxins in the present study had diverse assemblages of grazers. However, some samples clearly suggested PSP toxin accumulation in several different grazer taxa including tintinnids, heterotrophic dinoflagellates of the genus Protoperidinium , barnacle nauplii, the harpacticoid copepod Microsetella norvegica , the calanoid copepods Calanus finmarchicus and Pseudocalanus spp., the marine cladoceran Evadne nordmanni , and hydroids of the genus Clytia . Thus, a diverse assemblage of zooplankton grazers accumulated PSP toxins through food-web interactions. This raises the question of whether PSP toxins pose a potential human health risk not only from nearshore bivalve shellfish, but also potentially from fish and other upper-level consumers in zooplankton-based pelagic food webs.

  18. Effect of Organic Fertilizers on Zooplankton Production | Orji ...

    African Journals Online (AJOL)

    Effect of Organic Fertilizers on Zooplankton Production. ... Journal of Agriculture and Food Sciences ... The aquaria were thoroughly washed, filled with 20litres of bore-hole water, fertilized with the respective organic manures after 4 days fermentation and inoculated with zooplankton samples collected from an earthen fish ...

  19. Zooplankton as a compound mineralising and synthesizing system: Phosphorus excretion

    NARCIS (Netherlands)

    Gulati, R.D.; Martinez, C.P.; Siewertsen, K.

    1995-01-01

    Data on phosphate excretion rates of zooplankton are based on measurements using the pelagic crustacean zoo-plankton of Lake Vechten and laboratory-cultured Daphnia galeata. In case of Daphnia sp we measured the effects of feeding on P-rich algae and P-poor algae (Scenedesmus) as food on the

  20. Selective uptake of 55Fe from seawater by zooplankton

    International Nuclear Information System (INIS)

    Jennings, C.D.

    1978-01-01

    Iron-55 was measured in water and mixed zooplankton collected in the South Pacific Ocean. The ratios of the specific activity of 55 Fe (pCi/g Fe) between plankton and water from the same locations appear to be about 100, which suggests that zooplankton took up 55 Fe in preference to stable iron in the South Pacific Ocean

  1. Seasonal succession in zooplankton feeding traits reveals trophic trait coupling

    DEFF Research Database (Denmark)

    Kenitz, Kasia; Visser, Andre; Mariani, Patrizio

    2017-01-01

    non-motile cells flourishing in spring and motile community dominating during summer. The zooplankton community is dominated by active feeding-current feeders with peak biomass in the late spring declining during summer. The model reveals how zooplankton grazing reinforces protist plankton seasonal...

  2. Effects of UV-B irradiated algae on zooplankton grazing

    NARCIS (Netherlands)

    Lange, de H.J.; Lürling, M.F.L.L.W.

    2003-01-01

    We tested the effects of UV-B stressed algae on grazing rates of zooplankton. Four algal species ( Chlamydomonas reinhardtii, Cryptomonas sp., Scenedesmus obliquus and Microcystis aeruginosa) were used as food and fed to three zooplankton species ( Daphnia galeata, Bosmina longirostris and

  3. Zooplankton composition and community structure in Lake Tiga ...

    African Journals Online (AJOL)

    Zooplankton in Lake Tiga was identified and its community structure assessed between March 2009 and March 2011. A total of 54 species of zooplankton was recorded, comprising two species of Protozoa, 26 species of Rotifera, eight species of Copepoda, 11 species of Cladocera, four species of Ostracoda and three ...

  4. Monsoon regime in the Indian Ocean and zooplankton variability

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    and the estuaries in order to show how the monsoon exerts its influence on zooplankton from different types of environment. In the open ocean, the semi-annually reversing system of currents exert profound influence on the shifting of zooplankton populations and its...

  5. Biochemical composition of Antarctic zooplankton from the Indian Ocean sector

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Parulekar, A.H.

    Zooplankton samples were analysed for faunal composition, organic carbon, protein, carbohydrate and lipid content. Total zooplankton biomass (as displacement volume) varied from 0.032 to 0.500 ml.m sup(-3) (x = 0.23 + or - 0.14) in upper 200 m...

  6. Relationships among cyanobacteria, zooplankton and fish in sub-bloom conditions in the Sulejow Reservoir

    Directory of Open Access Journals (Sweden)

    Zbigniew Kaczkowski

    2017-01-01

    Full Text Available The occurrence of cyanobacteria is particularly characteristic of shallow eutrophic waters, and they often form massive ‘blooms’ that can affect aquatic invertebrates and fish. However, even a low abundance of cyanobacteria can be hazardous to aquatic organisms, due to the production of toxic metabolites. The aim of this study was to investigate the relationship between cyanobacteria and their toxicity (biological activity towards zooplankton and fish communities, when only low concentrations of cyanobacterial chlorophyll a (less than 20 μg L-1 are detected, i.e. in sub-bloom conditions. Measurements were performed in Sulejow Reservoir (Central Poland, a shallow, lowland, eutrophic reservoir, in which cyanobacterial blooms occur regularly. Fish were assessed using echo-sounding (distribution and by gillnetting (species composition. Simultaneously, zooplankton, cyanobacteria and physico-chemical characteristics were studied at 14 stations situated along hydroacoustic transects. Parameters that characterized the cyanobacteria (cyanobacterial chlorophyll a concentration, the number of 16S rRNA and the mcyA gene copies and microcystin (MC concentration were consistently correlated (based on a principal component analysis, and the highest values were found in the downstream region of the study area. This ‘cyano-complex’ was also positively correlated with oxygen concentration, pH and phosphate levels, but was negatively correlated with temperature and the concentrations of nitrates and nitrites. In Sulejow Reservoir in 2013 the biomass of large zooplankton filter feeders decreased along with increasing MC concentration and fish densities, while small filter feeders did not present such relationships with regards to fish densities. Fish abundance tended to decrease at stations with a lower abundance of cyanobacteria and with growing toxic genotype copies and MC concentration.

  7. Effects of a new molt-inducing insecticide, tebufenozide, on zooplankton communities in lake enclosures.

    Science.gov (United States)

    Kreutzweiser, D P; Thomas, D R

    1995-10-01

    : A potent ecdysone agonist, tebufenozide, has recently been developed as a molt-inducing insecticide to control defoliating lepidopterans. As part of continuing research efforts to assess the effectiveness and environmental safety of this material for insect pest management in Canadian forests, tebufenozide (RH-5992-2F) was applied to large lake enclosures and the effects on zooplankton communities were evaluated. There were significant treatment effects at all test concentrations (0.07-0.66 mg L(-1) tebufenozide). Concentration-dependent reductions in the abundance of cladocerans indicated that there were direct toxic effects of tebufenozide on this group of macrozooplankton. There were no indications of direct toxic effects on copepods. Significant increases in abundance of rotifers in treated enclosures at the three higher test concentrations were coincident with reductions in cladocerans and indicated secondary effects of the insecticide on the abundance of microzooplankton. There were no significant differences among treated and control enclosures in chlorophyll a concentrations, indicating that tebufenozide did not have direct effects on phytoplankton biomass, nor did the alterations in the zooplankton communities of treated enclosures have measurable secondary effects on phytoplankton biomass. Daytime dissolved oxygen concentrations were significantly higher in treated enclosures than in controls, indicating that the perturbation to biotic communities of some treated enclosures was sufficient to induce measurable changes in system-level functional attributes. Recovery of zooplankton communities in the enclosures occurred within 1-2 months at 0.07 and 0.13 mg l(-1) and by the following summer (12-13 months) at 0.33 and 0.66 mg l(-1).

  8. Grazing by Zooplankton on Diazotrophs in the Amazon River Plume and Western Tropical North Atlantic

    Science.gov (United States)

    Conroy, B.; Steinberg, D. K.; Song, B.; Foster, R.

    2016-02-01

    Organisms capable of fixing di-nitrogen (N2), known as diazotrophs, are important primary producers and a potentially significant source for new nitrogen entering the planktonic food web. However, limited evidence exists for zooplankton grazing on diazotrophs compared to other primary producers. In the western tropical North Atlantic Ocean (WTNA), the Amazon River plume creates a niche for symbiotic diatom-diazotroph associations (DDAs) which can form large blooms. In adjacent non-plume-influenced waters, the colonial cyanobacterium Trichodesmium is abundant. In order to reveal zooplankton-diazotroph grazing interactions and determine the fate of newly fixed nitrogen, gut contents of zooplankton captured in these two regions were compared based on quantitative PCR (qPCR) assay of nitrogenase genes (nifH), and their microbiomes compared using next generation sequencing (NGS) analysis of 16S rRNA genes. We sampled individual copepods from discrete depth intervals (0-25m and 25-50m) and in two size classes (0.5-1mm and 1-2mm) for analysis. A modified DNA extraction protocol was developed and 54 extracts were used as templates in nifH qPCR assays for the larger size fraction diazotrophs (>10µm): Trichodesmium, and Hemiaulus or Rhizosolenia (diatoms)-Richelia (diazotroph) associations. Copepod gut content nifH copies ranged from 1.6 to 13.6 copies individual-1 for the assay targeting the Hemiaulus-Richelia DDA and from 1.1 to 3.0 copies individual-1 for Trichodesmium. 16S NGS conducted on 35 extracts with an Ion Torrent PGM and mothur revealed that cyanobacteria sequences accounted for up to 20% of sequences per extract. Our results show that both DDAs and Trichodesmium are prey for zooplankton, and that new nitrogen moves through the food web via these grazing interactions. These interactions should be considered in future explorations of the global ocean nitrogen cycle.

  9. Zooplankton from Lake Magelungen, Central Sweden 1960-1963

    Energy Technology Data Exchange (ETDEWEB)

    Almquist, Elisabeth

    1970-11-15

    The investigation of the zooplankton of Lake Magelungen, Central Sweden, was carried out over a period of three years. The aim of the investigation was to illustrate the qualitative and quantitative composition of the zooplankton before the release of waste water from the Aagesta Heat and Power Station began. Vertical sampling series were collected once a month at three different stations in the lake. The highest volumes of zooplankton were obtained in the summer. The ciliates predominated when the conditions were unfavourable for other zooplankton, as in winter just below the ice. The rotifers dominated during and immediately after the spring circulation. With one exception the crustaceans reached their peak volume values in August or September. The composition of the zooplankton indicates that Lake Magelungen is highly eutrophic

  10. Zooplankton from Lake Magelungen, Central Sweden 1960-1963

    International Nuclear Information System (INIS)

    Almquist, Elisabeth

    1970-11-01

    The investigation of the zooplankton of Lake Magelungen, Central Sweden, was carried out over a period of three years. The aim of the investigation was to illustrate the qualitative and quantitative composition of the zooplankton before the release of waste water from the Aagesta Heat and Power Station began. Vertical sampling series were collected once a month at three different stations in the lake. The highest volumes of zooplankton were obtained in the summer. The ciliates predominated when the conditions were unfavourable for other zooplankton, as in winter just below the ice. The rotifers dominated during and immediately after the spring circulation. With one exception the crustaceans reached their peak volume values in August or September. The composition of the zooplankton indicates that Lake Magelungen is highly eutrophic

  11. In vitro propagation of endangered Dianthus taxa

    Directory of Open Access Journals (Sweden)

    Marković Marija

    2015-01-01

    Full Text Available The review of recent researches regarding the in vitro culture of 30 endangered Dianthus taxa is presented in this paper. Various in vitro protocols developed for selected rare and threatened Dianthus taxa are analysed in order to provide a useful synthesis of the data obtained with the main principles, techniques and recommendations for futher research and practice. The recapitulated data presented in this review can be used as a tool for the micropropagation of other endangered Dianthus taxa, enabling their propagation and obtaining a sufficient amount of plants for reintroduction. In addition, the obtained results represent the basis for ex situ conservation of the investigated taxa, especially for medium-term and long-term conservation (cryopreservation. [Projekat Ministarstva nauke Republike Srbije, br. 43007

  12. Regional zooplankton dispersal provides spatial insurance for ecosystem function.

    Science.gov (United States)

    Symons, Celia C; Arnott, Shelley E

    2013-05-01

    Changing environmental conditions are affecting diversity and ecosystem function globally. Theory suggests that dispersal from a regional species pool may buffer against changes in local community diversity and ecosystem function after a disturbance through the establishment of functionally redundant tolerant species. The spatial insurance provided by dispersal may decrease through time after environmental change as the local community monopolizes resources and reduces community invasibility. To test for evidence of the spatial insurance hypothesis and to determine the role dispersal timing plays in this response we conducted a field experiment using crustacean zooplankton communities in a subarctic region that is expected to be highly impacted by climate change - Churchill, Canada. Three experiments were conducted where nutrients, salt, and dispersal were manipulated. The three experiments differed in time-since-disturbance that the dispersers were added. We found that coarse measures of diversity (i.e. species richness, evenness, and Shannon-Weiner diversity) were generally resistant to large magnitude disturbances, and that dispersal had the most impact on diversity when dispersers were added shortly after disturbance. Ecosystem functioning (chl-a) was degraded in disturbed communities, but dispersal recovered ecosystem function to undisturbed levels. This spatial insurance for ecosystem function was mediated through changes in community composition and the relative abundance of functional groups. Results suggest that regional diversity and habitat connectivity will be important in the future to maintain ecosystem function by introducing functionally redundant species to promote compensatory dynamics. © 2012 Blackwell Publishing Ltd.

  13. Fine-Scale Distributions of Zooplankton in the Northern San Francisco Estuary

    Directory of Open Access Journals (Sweden)

    Wim Kimmerer

    2016-10-01

    Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss3art2 We studied zooplankton distributions in the upper San Francisco Estuary at nested scales of tens to thousands of meters. The purposes of the study were to assess how well the Interagency Ecological Program (IEP zooplankton monitoring represents abundance, and to investigate the variability of plankton on scales similar to those of foraging by fish. Samples were taken at three sites in the western Sacramento–San Joaquin Delta. We took 18 sets of six samples each with a plankton net along transects from near shore to center channel, and six sets of ten samples in the vicinity of a drifter either in mid-channel or near shore. Sampling took place in June–July 2014 during neap and spring tides, ebb and flood, day and night (transects only. Analysis focused on three common copepod species. Transect samples showed little consistent variation along transects, except that Pseudodiaptomus forbesi was less abundant nearshore than offshore by day at Big Break, the most landward site. The ratio of adults to adults + copepodites was strongly and positively related to turbidity by day but not by night, indicating demersal behavior. Drifter samples showed a minimum standard deviation of log10 sample counts of about 0.1, indicating that about two-thirds of replicate abundance values were within 80 % to 125% of the mean. A measure of difference between plankton samples at pairs of sample points was unrelated to distance between sample points for drifter samples, weakly related along transects for Limnoithona spp. stages, and strongly related for P. forbesi mainly because of the along-transect gradients at Big Break. The IEP sampling program is representative of plankton abundance except for demersal organisms, which can be ten-fold more abundant by night than by day. Small planktivorous fish could forage in patches of up to ~25% higher abundance than the mean.

  14. Seasonal dynamics of the copepod community in a tropical monsoonal estuary and the role of sex ratio in their abundance pattern

    Digital Repository Service at National Institute of Oceanography (India)

    Vineetha, G.; Madhu, N.V.; Kusum, K.K.; Sooria, P.M.

    structure of copepods in the tropical monsoonal estuarine system.The ecological scenario in the Cochin estuary revealed that irrespective of the season, higher zooplankton abundance occurred in the mesohaline zone (MSZ; salinity 5–18) of the estuary, despite...

  15. Zooplankton variability in the subtropical estuarine system of Paranaguá Bay, Brazil, in 2012 and 2013

    Science.gov (United States)

    Salvador, Bianca; Bersano, José Guilherme F.

    2017-12-01

    Spatial and temporal dynamics of zooplankton assemblages were studied in the Paranaguá Estuarine System (southern Brazil), including data from the summer (rainy) and winter (dry) periods of 2012 and 2013. Zooplankton and environmental data were collected at 37 stations along the estuary and examined by multivariate methods. The results indicated significantly distinct assemblages; differences in abundance were the major source of variability, mainly over the temporal scale. The highest abundances were observed during rainy periods, especially in 2012, when the mean density reached 16378 ind.m-3. Winter assemblages showed lower densities but higher species diversity, due to the more extensive intrusion of coastal waters. Of the 14 taxonomic groups recorded, Copepoda was the most abundant and diverse (92% of total abundance and 22 species identified). The coastal copepods Acartia lilljeborgi (44%) and Oithona hebes (26%) were the most important species in both abundance and frequency, followed by the estuarine Pseudodiaptomus acutus and the neritic Temora turbinata. The results indicated strong influences of environmental parameters on the community structure, especially in response to seasonal variations. The spatial distribution of species was probably determined mainly by their preferences and tolerances for specific salinity conditions. On the other hand, the abundances were strongly related to higher water temperature and precipitation rates, which can drive nutrient inputs and consequently food supply in the system, due to intense continental drainage.

  16. The impact of different hydrographic conditions and zooplankton communities on provisioning Little Auks along the West coast of Spitsbergen

    Science.gov (United States)

    Kwasniewski, Slawomir; Gluchowska, Marta; Jakubas, Dariusz; Wojczulanis-Jakubas, Katarzyna; Walkusz, Wojciech; Karnovsky, Nina; Blachowiak-Samolyk, Katarzyna; Cisek, Malgorzata; Stempniewicz, Lech

    2010-10-01

    Composition and abundance of zooplankton were studied simultaneously with feeding ecology of planktivorous Little Auks ( Alle alle) in two different sea shelf areas of West Spitsbergen, Norway, in summer 2007. Zooplankton was collected adjacent to bird colonies in Magdalenefjorden (influenced by Atlantic West Spitsbergen Current) and Hornsund (dominated by the Arctic Sørkapp Current). In spite of different hydrological situations, the abundance of prey preferred by Little Auks, Arctic Calanus glacialis copepodids stage V, among zooplankton was similar in both localities. However, there was much more of Atlantic Calanus finmarchicus on the shelf outside Magdalenefjorden compared to Hornsund, resulting in different abundance ratios of Arctic to Atlantic copepods in the two areas (1:14 and 1:1, respectively). Even greater differences between the two areas occurred in the ratio of C. glacialis CV to other zooplankters, amounting to 1:40 in Magdalenefjorden and 1:6 in Hornsund. In both Little Auk colonies food brought by parents to their chicks contained mainly C. glacialis CV, albeit the proportion of this copepod in meals was significantly higher in Hornsund. Meals delivered to Little Auk chicks in Hornsund had also higher zooplankton numbers, biomass and energy content. In Magdalenefjorden, on the other hand, a higher number of feedings and longer duration of foraging trips were recorded. These differences became more apparent with increasing energy requirements of the fast growing nestlings. This was probably a consequence of lower relative abundance of the Little Auks’ preferred prey in the sea adjacent to Magdalenefjorden colony. It seems that searching for the preferred food items, such as C. glacialis, among abundant but less favored C. finmarchicus, may require more time and energy demanding foraging behavior. As a consequence, foraging effort of the Little Auk parents from Magdalenefjorden was higher, and feeding efficiency lower, than those of birds from

  17. Maximum parsimony on subsets of taxa.

    Science.gov (United States)

    Fischer, Mareike; Thatte, Bhalchandra D

    2009-09-21

    In this paper we investigate mathematical questions concerning the reliability (reconstruction accuracy) of Fitch's maximum parsimony algorithm for reconstructing the ancestral state given a phylogenetic tree and a character. In particular, we consider the question whether the maximum parsimony method applied to a subset of taxa can reconstruct the ancestral state of the root more accurately than when applied to all taxa, and we give an example showing that this indeed is possible. A surprising feature of our example is that ignoring a taxon closer to the root improves the reliability of the method. On the other hand, in the case of the two-state symmetric substitution model, we answer affirmatively a conjecture of Li, Steel and Zhang which states that under a molecular clock the probability that the state at a single taxon is a correct guess of the ancestral state is a lower bound on the reconstruction accuracy of Fitch's method applied to all taxa.

  18. The zooplankton community of Lake Abo Zaabal, a newly-formed ...

    African Journals Online (AJOL)

    Cladocera were seldom recorded. Hexarthra, Brachionus and Rotaria were the dominant rotifer taxa. Several characteristics — including the community composition, the dominance of small ciliates and nauplii, the abundance of Cyanobacteria, and the absence of macrophytes — indicated that it is a severely eutrophic lake.

  19. Indicator taxa revisited: useful for conservation planning?

    DEFF Research Database (Denmark)

    Larsen, Frank Wugt; Bladt, Jesper; Rahbek, Carsten

    2009-01-01

    Aim:  Indicators for biodiversity are needed to facilitate the identification of complementary reserve networks for biodiversity conservation. One widely adopted approach is to use indicator taxa, i.e. a single taxon such as birds or butterflies, despite the ongoing debate regarding their usefuln......Aim:  Indicators for biodiversity are needed to facilitate the identification of complementary reserve networks for biodiversity conservation. One widely adopted approach is to use indicator taxa, i.e. a single taxon such as birds or butterflies, despite the ongoing debate regarding...

  20. Comparative larval growth and mortality of mesopelagic fishes and their predatory impact on zooplankton in the Kuroshio region

    Science.gov (United States)

    Sassa, Chiyuki; Takahashi, Motomitsu

    2018-01-01

    Larvae of mesopelagic fishes usually dominate in oceanic larval fish assemblages, but detailed investigations of their ecology are limited and thus preclude full assessment of the ecosystem structure and dynamics in oceanic waters. Here, we examined the growth and mortality of six taxa of numerically dominant mesopelagic fish larvae and their predatory impact on zooplankton in the Kuroshio region off southern Japan during late winter. The weight-specific growth coefficient (Gw) ranged from 0.077 (Sigmops gracilis) to 0.156 d-1 (Vinciguerria nimbaria), and the instantaneous daily mortality coefficient (M) from 0.067 (S. gracilis) to 0.143 d-1 (Myctophum asperum). The ratio Gw/M, an index of stage-specific survival of the larvae, was from 0.90 (Notoscopelus japonicus) to 1.24 (V. nimbaria), without a significant difference from a value of 1 in all species. Based on the reported relationship between Gw and ingestion rate of the larval fishes, the daily ration of each species was calculated to be 32-57% of body dry weight d-1. Mean and 95% confidence interval of food requirements of the six taxa of larvae was 1.41 ± 0.55 mg C m-2 d-1. Predatory impact of the mesopelagic fish larvae on the production rate of the available prey was estimated to be approximately 3.5-5.2%, implying that the larvae have a low level but consistent effect on zooplankton production in the oligotrophic Kuroshio region.

  1. Increased fitness of a key appendicularian zooplankton species under warmer, acidified seawater conditions.

    Directory of Open Access Journals (Sweden)

    Jean-Marie Bouquet

    Full Text Available Ocean warming and acidification (OA may alter the fitness of species in marine pelagic ecosystems through community effects or direct physiological impacts. We used the zooplanktonic appendicularian, Oikopleura dioica, to assess temperature and pH effects at mesocosm and microcosm scales. In mesocosms, both OA and warming positively impacted O. dioica abundance over successive generations. In microcosms, the positive impact of OA, was observed to result from increased fecundity. In contrast, increased pH, observed for example during phytoplankton blooms, reduced fecundity. Oocyte fertility and juvenile development were equivalent under all pH conditions, indicating that the positive effect of lower pH on O. dioica abundance was principally due to increased egg number. This effect was influenced by food quantity and quality, supporting possible improved digestion and assimilation at lowered pH. Higher temperature resulted in more rapid growth, faster maturation and earlier reproduction. Thus, increased temperature and reduced pH had significant positive impacts on O. dioica fitness through increased fecundity and shortened generation time, suggesting that predicted future ocean conditions may favour this zooplankton species.

  2. Tidal Influence on the Diel Vertical Migration Pattern of Zooplankton in a Tropical Monsoonal Estuary

    KAUST Repository

    Vineetha, G.

    2015-04-03

    Monsoonal estuaries, located along the coastline of the Indian subcontinent, differ from other estuaries by their time dependence on the salinity characteristics. Effective sustenance and retention of the mesozooplankton community in the estuarine habitats is often determined by their dominant behavioral patterns: diel vertical migration (DVM) and tidal vertical migration (TVM). The modes of these endogenous rhythms often vary among estuaries based on the river runoff and tidal characteristics. The present study is a pioneering attempt to depict the vertical migration pattern of zooplankton along a diel and tidal scale in a tropical, microtidal, monsoonal estuary. We observed that in spite of the prominent asymmetry in the magnitude of the river runoff between the seasons, most of the zooplankton groups exhibited strong DVM, with a clear increase in biomass and abundance in surface waters during night. The peak increase in biomass and abundance at night always synchronized with the slack periods in the tidal cycles, which differed from the general concepts of downward migration during ebb tide and upward migration during flood tide in estuarine systems. The weak currents during the slack period might have favored the effective vertical migration of the mesozooplankton community in this monsoonal estuarine system. © 2015 Society of Wetland Scientists

  3. Zooplankton data collected by ELTANIN in Southern Oceans from zooplankton net casts; 13 October 1963 to 06 June 1968 (NODC Accession 9500111)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts from ELTANIN in the Southern Oceans. Data were collected from 13 October 1963 to 06 June 1968 by National...

  4. Zooplankton species identities collected from zooplankton net casts in Indian Ocean from 17 February 1960 to 23 July 1962 (NODC Accession 9400059)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton species identities and other data were collected using zooplankton net casts in the Indian Ocean. Data were collected from 17 February 1960 to 23 July...

  5. Zooplankton ecology of the mangrove habitats of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    and fish larvae constituted bulk of zooplankton. Majority of these organisms were stragglers. The zooplankters showing better eco-physiological adaptations colonized in pools surroundEd. by thick mangroves vegetation...

  6. Dredging induced changes in zooplankton community and water ...

    African Journals Online (AJOL)

    user

    water characteristics and zooplankton community structure in Dal Lake. An assessment was done ... et al., 2007; Zhang et al., 2010). In aquatic ecosystems, .... generally high in fine grain sediment (Fisher et al., 1982;. Valiela, 1995). In post ...

  7. Understanding cyanobacteria-zooplankton interactions in a more eutrophic world

    NARCIS (Netherlands)

    Ger, K.A.; Hansson, L.; Lurling, M.F.L.L.W.

    2014-01-01

    1.We review and update recent observations of cyanobacteria–zooplankton interactions, identify theoretical and methodological limitations and evaluate approaches necessary for understanding the effects of increasing cyanobacterial blooms on plankton dynamics. 2.The emphasis on oversimplified studies

  8. impact of physicochemical factors on zooplankton species richness

    African Journals Online (AJOL)

    DR. AMINU

    This study revealed that physicochemical fluctuations was negative impact on the zooplankton species ... of convergence of wastewater streams, of which Jakara River carries ..... Discharge on Physicochemical Parameters and Some Heavy ...

  9. Zooplankton characteristics of the coastal ecosystem off Bombay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Ramaiah, Neelam

    spinicauda) dominated the copepod community. Four species of chaetognaths were found in the area with predominance of Sagitta bedoti. Among the penaeid larvae Metapenaeus offinis was the most common species. Population of omnivores dominated the zooplankton...

  10. Metals in coastal zooplanktons - A coastal living resource hazard

    Digital Repository Service at National Institute of Oceanography (India)

    Paimpillil, J.S.; Joseph, T.; Rejomon, G.; Gerson, V.J.

    are linked to bioaccumulation. The biological concentration factor and metal contents in zooplankton is appreciably varied for all the elements except for iron and zinc. The above findings clearly indicates the importance of bioavailability of metals...

  11. Dynamics of the zooplankton assemblage of Ojirami Reservoir, Edo ...

    African Journals Online (AJOL)

    Zooplankton form an important trophic link between phytoplankton and fish in ... with water temperature and water level; and positive with alkalinity, free CO2 and phosphate. The study revealed low pollution indicator species in the reservoir ...

  12. Diversity and seasonal variation of zooplankton of Lake Hlan ...

    African Journals Online (AJOL)

    SARAH

    2016-06-30

    Jun 30, 2016 ... The taxonomic composition and the species ... Keywords: Biodiversity; Community structure; Hydrological season; Zooplankton .... Table 1: Seasonal change in recorded environmental parameters ..... reproduction, growth and life duration (Fernandez de .... Spatial temporal patterns and relationships with.

  13. Zooplankton composition in Dharamtar creek adjoining Bombay harbour

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, L.R.; Nair, V.R.

    bedoti was the true inhabitant. In general zooplankton production indicated 1.5 fold increase towards the upper reaches of the creek where salinity variations were drastic. A more diversified faunal assemblage of oceanic and neritic species characterised...

  14. Zooplankton composition of the Kalpeni and Agatti atolls, Lakshadweep archiplago

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Haridas, P.; Madhupratap, M.

    Composition of zooplankton in the lagoons was quite different from that of the sea and to a large extent, was independent of oceanic influence While copepods were dominant in the sea, meroplankton, particularly brachyuran zoeae constituted...

  15. Procedures Involved in Radioecological Studies with Marine Zooplankton

    International Nuclear Information System (INIS)

    Fowler, S.W.; Small, L.F.

    1976-01-01

    Various procedures in marine radio ecological experiments with zooplankton are considered in the light of the possibility of establishing reference methods for marine radiobiological studies. Methods for collection, handling and maintenance prior to and during experiments are suggested for various types of zooplankton. The importance of physiological and physicochemical parameters are discussed in the context of the experimental design with the aim of achieving comparable results among workers involved in this field of research. (author)

  16. Can microcystins affect zooplankton structure community in tropical eutrophic reservoirs?

    Directory of Open Access Journals (Sweden)

    T. A. S. V. Paes

    Full Text Available Abstract The aim of our study was to assess whether cyanotoxins (microcystins can affect the composition of the zooplankton community, leading to domination of microzooplankton forms (protozoans and rotifers. Temporal variations in concentrations of microcystins and zooplankton biomass were analyzed in three eutrophic reservoirs in the semi-arid northeast region of Brazil. The concentration of microcystins in water proved to be correlated with the cyanobacterial biovolume, indicating the contributions from colonial forms such as Microcystis in the production of cyanotoxins. At the community level, the total biomass of zooplankton was not correlated with the concentration of microcystin (r2 = 0.00; P > 0.001, but in a population-level analysis, the biomass of rotifers and cladocerans showed a weak positive correlation. Cyclopoid copepods, which are considered to be relatively inefficient in ingesting cyanobacteria, were negatively correlated (r2 = – 0.01; P > 0.01 with the concentration of cyanotoxins. Surprisingly, the biomass of calanoid copepods was positively correlated with the microcystin concentration (r2 = 0.44; P > 0.001. The results indicate that allelopathic control mechanisms (negative effects of microcystin on zooplankton biomass do not seem to substantially affect the composition of mesozooplankton, which showed a constant and high biomass compared to the microzooplankton (rotifers. These results may be important to better understand the trophic interactions between zooplankton and cyanobacteria and the potential effects of allelopathic compounds on zooplankton.

  17. Effect of Spent Lubricating Oil on the Composition and Abundance ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... The Modified Berlese-Tullgren Funnel method was used for the extraction of soil arthropod fauna. ... Soil arthropod taxa and abundance were significantly lower (u(2) = 51, ...

  18. River discharge as a major driving force on spatial and temporal variations in zooplankton biomass and community structure in the Godavari estuary India.

    Science.gov (United States)

    Venkataramana, V; Sarma, V V S S; Matta Reddy, Alavala

    2017-08-28

    Variability in horizontal zooplankton biomass distribution was investigated over 13 months in the Godavari estuary, along with physical (river discharge, temperature, salinity), chemical (nutrients, particulate organic matter), biological (phytoplankton biomass), and geological (suspended matter) properties to examine the influencing factors on their spatial and temporal variabilities. The entire estuary was filled with freshwater during peak discharge period and salinity near zero, increased to ~ 34 psu during dry period with relatively high nutrient levels during former than the latter period. Due to low flushing time ( 500 mg L -1 ) during peak discharge period, picoplankton (cyanophyceae) contributed significantly to the phytoplankton biomass (Chl-a) whereas microplankton and nanoplankton (bacillariophyceae, and chlorophyceae) during moderate and mostly microplankton during dry period. Zooplankton biomass was the lowest during peak discharge period and increased during moderate followed by dry period. The zooplankton abundance was controlled by dead organic matter during peak discharge period, while both phytoplankton biomass and dead organic matter during moderate discharge and mostly phytoplankton biomass during dry period. This study suggests that significant modification of physico-chemical properties by river discharge led to changes in phytoplankton composition and dead organic matter concentrations that alters biomass, abundance, and composition of zooplankton in the Godavari estuary.

  19. Ecological patterns, diversity and core taxa of microbial communities in groundwater-fed rapid gravity filters

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    2016-01-01

    Here, we document microbial communities in rapid gravity filtration units, specifically serial rapid sand filters (RSFs), termed prefilters (PFs) and after- filters (AFs), fed with anoxic groundwaters low in organic carbon to prepare potable waters. A comprehensive 16S rRNA-based amplicon...... sequencing survey revealed a core RSF microbiome comprising few bacterial taxa (29–30 genera) dominated by Nitrospirae, Proteobacteria and Acidobacteria, with a strikingly high abundance (75–87±18%) across five examined waterworks in Denmark. Lineages within the Nitrospira genus consistently comprised...... the second most and most abundant fraction in PFs (27±23%) and AFs (45.2±23%), respectively, and were far more abundant than typical proteobacterial ammonium-oxidizing bacteria, suggesting a physiology beyond nitrite oxidation for Nitrospira. Within the core taxa, sequences closely related to types...

  20. Multilevel regularized regression for simultaneous taxa selection and network construction with metagenomic count data.

    Science.gov (United States)

    Liu, Zhenqiu; Sun, Fengzhu; Braun, Jonathan; McGovern, Dermot P B; Piantadosi, Steven

    2015-04-01

    Identifying disease associated taxa and constructing networks for bacteria interactions are two important tasks usually studied separately. In reality, differentiation of disease associated taxa and correlation among taxa may affect each other. One genus can be differentiated because it is highly correlated with another highly differentiated one. In addition, network structures may vary under different clinical conditions. Permutation tests are commonly used to detect differences between networks in distinct phenotypes, and they are time-consuming. In this manuscript, we propose a multilevel regularized regression method to simultaneously identify taxa and construct networks. We also extend the framework to allow construction of a common network and differentiated network together. An efficient algorithm with dual formulation is developed to deal with the large-scale n ≪ m problem with a large number of taxa (m) and a small number of samples (n) efficiently. The proposed method is regularized with a general Lp (p ∈ [0, 2]) penalty and models the effects of taxa abundance differentiation and correlation jointly. We demonstrate that it can identify both true and biologically significant genera and network structures. Software MLRR in MATLAB is available at http://biostatistics.csmc.edu/mlrr/. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. How well does the Continuous Plankton Recorder (CPR) sample zooplankton? A comparison with the Longhurst Hardy Plankton Recorder (LHPR) in the northeast Atlantic

    Science.gov (United States)

    Richardson, Anthony J.; John, Eurgain H.; Irigoien, Xabier; Harris, Roger P.; Hays, Graeme C.

    2004-09-01

    The Continuous Plankton Recorder (CPR) survey has collected data on basin-scale zooplankton abundance in the North Atlantic since the 1930s. These data have been used in many studies to elucidate seasonal patterns and long-term change in plankton populations, as well as more recently to validate ecosystem models. There has, however, been relatively little comparison of the data from the CPR with that from other samplers. In this study we compare zooplankton abundance estimated from the CPR in the northeast Atlantic with near-surface samples collected by a Longhurst-Hardy Plankton Recorder (LHPR) at Ocean Weather Station India (59°N, 19°W) between 1971 and 1975. Comparisons were made for six common copepods in the region: Acartia clausi, Calanus finmarchicus, Euchaeta norvegica, Metridia lucens, Oithona sp., and Pleuromamma robusta. Seasonal cycles based on CPR data were similar to those recorded by the LHPR. Differences in absolute abundances were apparent, however, with the CPR underestimating abundances by a factor of between 5 and 40, with the exception of A. clausi. Active avoidance by zooplankton is thought to be responsible. This avoidance is species specific, so that care must be taken describing communities, as the CPR emphasises those species that are preferentially caught, a problem common to many plankton samplers.

  2. Zooplankton data: Vertical distributions of zooplankton in the Norweigian and Greenland Seas during summer, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Lane, P.V.Z.; Smith, S.L.; Schwarting, E.M.

    1993-08-01

    Recent studies of zooplankton populations in the Greenland Sea have focused on processes at the Marginal Ice Zone (MIZ) and the areas immediately adjacent to it under the ice and in open water. These studies have shown a relatively short period of intense secondary productivity which is closely linked temporally and spatially to phytoplankton blooms occurring near the ice edge in spring and early summer. During the summer of 1989 we participated in a project focusing on benthic and water column processes in the basins of the Norwegian and Greenland Seas. This study allowed us to compare biological processes at the MIZ with those occurring in the open waters of the Greenland Sea, and to compare processes at both of these locations with those in the Norwegian Sea. The data presented in this report are the results of zooplankton net tows covering the upper 1000 meters of the water column over the Norwegian Sea basin and the Greenland Sea basin, and the upper 500 meters of open water adjacent to the MIZ in the Greenland Sea. Sampling was conducted between 12 and 29 July 1989.

  3. Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

    KAUST Repository

    Bagchi, Samik

    2014-10-19

    In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different solids retention time (SRT). Rank-abundance curves showed few dominant operational taxonomic units (OTUs) and a long tail of rare OTUs in all reactors. Results revealed that there was no detectable effect of SRT (2 vs. 10 days) on Shannon diversity index and OTU richness of both dominant and rare taxa. Nonmetric multidimensional scaling analysis showed that the total, dominant, and rare bacterial taxa were highly dynamic during the entire period of stable reactor performance. Also, the rare taxa were more dynamic than the dominant taxa despite expected low invasion rates because of the use of sterile synthetic media.

  4. 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.

  5. Climate-induced signatures in the zooplankton communities: a meta-analysis at a European scale.

    Directory of Open Access Journals (Sweden)

    Sónia Cotrim Marques

    2014-05-01

    Full Text Available Several recent studies have revealed the impacts of the climate variability in the dynamic of zooplankton in different estuarine ecosystems, imposing a need for more and continued global studies. Presently, there is a growing appreciation in international collaborations to compare and contrast estuarine ecosystem response to climate variability across geographical gradients, including long-term changes in zooplankton. We performed a meta-analysis comprising field data from 7 location (Mondego estuary-Portugal, Seine estuary- France, Sheldt estuary- Belgium, Kiel fjord - Germany, Gulf of Riga- Latvia, Gulf of Bothnia – Sweden and Finland Archipelagos. The use of climatic modes (e.g. NAO, ENSO has proven useful in investigating links between climatic variations and ecological patterns. Therefore, the main focus will be to test the influence of the NAO on abundance of organisms, key species, local environment and whether these relationships are generally positive, whether they are sensitive to methodological differences among studies, between taxonomic group and key species. The knowledge gained will contribute to quantitatively evaluate the multi-scale structure of climate and marine environment and to identify a set of environmental indicators to assess the estuarine ecosystem state and risks for ecological shifts.

  6. Diurnal variation in zooplankton in the Zuari Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Padmavati, G.; Goswami, S.C.; Vidya, P.S.

    Variations in zooplankton biomass and population density in relation to the prevailing hydrographical conditions were studied in Zuari Estuary, Goa. The physico-chemical parameters showed limited variations. Zooplankton biomass was relatively more...

  7. Diel variations in zooplankton and their biochemical composition from Vengurla to Ratnagiri, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; KrishnaKumari, L.; Shrivastava, Y.

    Diel variations in zooplankton biomass, common groups and proximate composition zooplankton at stations between Vengurla to Ratnagiri, along west coast of India were studied. Higher biomass values were obtained for the night samples (av = 80 ml/100...

  8. Effect of tide on the variability of zooplankton in the nearshore waters of Thal, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N; Nair, V.R.; Krishnakumari, L; Desai, B.N

    Quantitative and qualitative difference in zooplankton in relation to the tide were studied along 3 transects located off Thal, Maharashtra, India during Feb. 1980 to Jan. 1981. Variation in zooplankton biomass for the flood and ebb period were 2...

  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.

    Annual variations in the zooplankton biomass and composition during 1991-92 were studied from the inshore, mouth and upstream regions of the Burhabalanga Estuary located in the Orissa Coast (India). Zooplankton biomass was maximum at all...

  10. Production and associations of zooplankton in estuarine and nearshore waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    Zooplankton production in the Zuari and Mandovi estuaries indicated 2 peaks-one in November and another in March/April. In the nearshore waters very high value of zooplankton biomass was observed in April associated with Trichodesmium bloom. Mean...

  11. Interactions of phytoplankton, zooplankton and microorganisms

    Science.gov (United States)

    Pomeroy, L. R.; Paffenhöfer, G.-A.; Yoder, J. A.

    We present evidence that there are significant interactions between heterotrophic microorganisms, doliolids and Fritillaria within intrusions of nutrient-rich Gulf Stream water stranding on the continental shelf. During the summer of 1981 cold, nutrient-rich water from below the surface of the Gulf Stream was repeatedly intruded and stranded on the continental shelf off northeastern Florida. On August 6 old, stranded Gulf Stream water depleted of nitrate occupied the lower layer on the outer shelf. The upper water was continental shelf water, older but of undefined age. On August 6 free-living bacteria were >10 6ml -1 everywhere at all depths, an order of magnitude greater than normal bacterial numbers on the northeastern Florida continental shelf. Over 10 days the numbers of free bacteria doubled while bacteria attached to particles increased by a factor of four. The adenylate/chlorophyll ratio showed that phytoplankton dominated the lower layers of intruded water, while the surface water became increasingly dominated by heterotrophic microorganisms (bacteria and protozoa) over 10 days. There were significant, negative correlations between bacteria and doliolids and between bacteria and Fritillaria. Regions of maximum bacterial numbers did not coincide with locations of salp swarms. The increased numbers of bacteria at all depths in a highly stratified system in which most phytoplankton are in the lower layer suggests a diverse source of bacterial growth substrates, some of which involve zooplankton as intermediaries. Production of autotrophs is more than twice that of microheterotrophs on average, but because of their differential distribution, microheterotrophs are the dominant biomass in much of the surface water and may be significant in energy flux to metazoan consumers as well as competitors for mutually useable sources of nutrition.

  12. Feeding on dispersed vs. aggregated particles: The effect of zooplankton feeding behavior on vertical flux

    DEFF Research Database (Denmark)

    Koski, Marja; Boutorh, Julia; De La Rocha, Christina L.

    2017-01-01

    Zooplankton feeding activity is hypothesized to attenuate the downward flux of elements in the ocean. We investigated whether the zooplankton community composition could influence the flux attenuation, due to the differences of feeding modes (feeding on dispersed vs. aggregated particles) and of ......Zooplankton feeding activity is hypothesized to attenuate the downward flux of elements in the ocean. We investigated whether the zooplankton community composition could influence the flux attenuation, due to the differences of feeding modes (feeding on dispersed vs. aggregated particles...

  13. Numerical studies of the influence of food ingestion on phytoplankton and zooplankton biomasses

    OpenAIRE

    Lidia Dzierzbicka-G³owacka

    2002-01-01

    This paper presents the numerical simulations of the influence of food ingestion by a herbivorous copepod on phytoplankton and zooplankton biomasses (PZB) in the sea. The numerical studies were carried out using the phytoplankton-zooplankton-nutrient-detritus PhyZooNuDe biological upper layer model. This takes account both of fully developed primary production and regeneration mechanisms and of daily migration of zooplankton. In this model the zooplankton is treated not as a 'biomass' but as ...

  14. Magnetic Field Fluctuations Due to Diel Vertical Migrations of Zooplankton

    Science.gov (United States)

    Dean, C.; Soloviev, A.

    2016-12-01

    Dean et al. (2016) have indicated that at high zooplankton concentrations, diel vertical migrations (DVM) cause velocity fluctuations and a respective increase of the dissipation rate of turbulent kinetic energy (TKE). In this work, we used a 3D non-hydrostatic computational fluid dynamics model with Lagrangian particle injections (a proxy for migrating organisms) via a discrete phase model to simulate the effect of turbulence generation by DVM. We tested a range of organism concentrations from 1000 to 10,000 organisms/m3. The simulation at an extreme concentration of zooplankton showed an increase in dissipation rate of TKE by two to three orders of magnitude during DVM over background turbulence, 10-8 W kg-1. At lower concentrations (Frank, J. Wood, 2016: Biomixing due to diel vertical migrations of zooplankton. Ocean Modelling 98, 51-64.

  15. Effects of inorganic turbidity and reservoir floods on the feeding and population dynamics of Cladoceran zooplankton

    International Nuclear Information System (INIS)

    Shuman, J.R.

    1988-01-01

    Clearance rates of 32 P-labeled yeast cell tracer particles and gravimetric seston analysis were used to estimate in situ seston ingestion rates of Daphnia parvula and Bosmina along the seston gradient in Tuttle Creek Reservoir, near Manhattan, Kansas. An ingestion rate depression occurred for both species at the highest seston concentration. The smallest animals, Bosmina, had a lower incipient limiting concentration and exhibited a stronger ingestion rate depression. The fecundity and abundance of Daphnia parvula, grown in enclosures along the seston gradient prior to the ingestion rate measurements, were highest at the river inflow region. Reservoir Bosmina, however, were least abundant and had the lowest fecundity at the river inflow region. The abundance of Bosmina, calanoid copepods, and cyclopoid copepods were lower following large storm inflows in the late spring of 1983 and 1984, while the abundance of Diaphanosoma and Moina were similar. Both open reservoir and in situ enclosure populations of Daphnia pulex were reduced following the storm inflow, while only enclosure populations of Daphnia parvula were lower. Diaphanosoma and calanoid copepods dominated the zooplankton during sampling from spring through fall 1984, particularly in midsummer when temperatures were greater than 25 degree C. Daphnids dominated numerically during the fall baseflow period

  16. Differential growth responses of soil bacterial taxa to carbon substrates of varying chemical recalcitrance

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, K.C.; Karaoz, U.; Hanson, C.A.; Santee, C.A.; Bradford, M.A.; Treseder, K.K.; Wallenstein, M.D.; Brodie, E.L.

    2011-04-18

    Soils are immensely diverse microbial habitats with thousands of co-existing bacterial, archaeal, and fungal species. Across broad spatial scales, factors such as pH and soil moisture appear to determine the diversity and structure of soil bacterial communities. Within any one site however, bacterial taxon diversity is high and factors maintaining this diversity are poorly resolved. Candidate factors include organic substrate availability and chemical recalcitrance, and given that they appear to structure bacterial communities at the phylum level, we examine whether these factors might structure bacterial communities at finer levels of taxonomic resolution. Analyzing 16S rRNA gene composition of nucleotide analog-labeled DNA by PhyloChip microarrays, we compare relative growth rates on organic substrates of increasing chemical recalcitrance of >2,200 bacterial taxa across 43 divisions/phyla. Taxa that increase in relative abundance with labile organic substrates (i.e., glycine, sucrose) are numerous (>500), phylogenetically clustered, and occur predominantly in two phyla (Proteobacteria and Actinobacteria) including orders Actinomycetales, Enterobacteriales, Burkholderiales, Rhodocyclales, Alteromonadales, and Pseudomonadales. Taxa increasing in relative abundance with more chemically recalcitrant substrates (i.e., cellulose, lignin, or tannin-protein) are fewer (168) but more phylogenetically dispersed, occurring across eight phyla and including Clostridiales, Sphingomonadalaes, Desulfovibrionales. Just over 6% of detected taxa, including many Burkholderiales increase in relative abundance with both labile and chemically recalcitrant substrates. Estimates of median rRNA copy number per genome of responding taxa demonstrate that these patterns are broadly consistent with bacterial growth strategies. Taken together, these data suggest that changes in availability of intrinsically labile substrates may result in predictable shifts in soil bacterial composition.

  17. Flow disturbances generated by feeding and swimming zooplankton

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Jiang, Haisong; Goncalves, R. J.

    2014-01-01

    that zooplankton, in which feeding and swimming are separate processes, produce flow disturbances during swimming with a much faster spatial attenuation (velocity u varies with distance r as u ∝ r−3 to r−4) than that produced by zooplankton for which feeding and propulsion are the same process (u ∝ r−1 to r−2...... vortex rings, or by “breast-stroke swimming.” Both produce rapidly attenuating flows. The more “noisy” swimming of those that are constrained by a need to simultaneously feed is due to constantly beating flagella or appendages that are positioned either anteriorly or posteriorly on the (cell) body...

  18. An evaluation of the zooplankton community at the Sheboygan River Area of Concern and non-Area of Concern comparison sites in western Lake Michigan rivers and harbors in 2016

    Science.gov (United States)

    Olds, Hayley T.; Scudder Eikenberry, Barbara C.; Burns, Daniel J.; Bell, Amanda H.

    2017-12-22

    no significant difference between the zooplankton community composition and structure in the AOC and non-AOC sites. Zooplankton taxa richness in the AOC was rated as “not degraded” in 2016 because of significantly higher taxa richness values in samples collected from the Sheboygan River AOC, compared with the non-AOC sites as a group (that is, data pooled from both non-AOC sites). Zooplankton diversity in 2016, however, was characterized as “degraded” in the AOC on the basis of significantly lower (p<0.05) values in samples collected from the AOC compared with those collected from the non-AOC sites as a group. Annual variation in zooplankton community composition and structure at the Sheboygan River AOC was significantly different among all 3 years sampled, as indicated by an analysis of similarity test. Zooplankton richness was significantly higher in 2014 than in both 2012 and 2016, and diversity was significantly higher in 2012 than in both 2014 and 2016. Postremediation recovery can often be complicated by non-AOC-related stressors such as nutrients, invasive species, and extremes in flow, which could affect the recovery of zooplankton communities in the Sheboygan River AOC. The effect of the stressors on postremediation recovery underscores the importance of sampling multiple years when assessing the effectiveness of remediation activities. The results from this study will be used by the Wisconsin Department of Natural Resources and the U.S. Environmental Protection Agency to determine if restoration efforts have been effective in removing the plankton BUI and to monitor future conditions in the AOC.

  19. Variation in zooplankton prey distribution determines marine foraging distributions of breeding Cassin's Auklet

    Science.gov (United States)

    Bertram, Douglas F.; Mackas, David L.; Welch, David W.; Boyd, W. Sean; Ryder, John L.; Galbraith, Moira; Hedd, April; Morgan, Ken; O'Hara, Patrick D.

    2017-11-01

    To investigate the causal basis for patterns of seabird foraging distributions during breeding we integrated data from ship-board seabird and zooplankton surveys, aerial radio telemetry, and colony-based research programs. We examined the marine distributions of Cassin's Auklet (Ptychoramphus aleuticus) breeding on Triangle Island, in the Northeast Pacific off the coast of B.C., Canada using surveys conducted in 1999, 2000, and 2001. Concurrently, we sampled zooplankton at 16 stations along a cross shelf transect in the vicinity of Triangle Island. In 1999 and 2000, when populations of the preferred copepod prey Neocalanus cristatus were available at deep-water stations (1000-2000 m), the majority of the auklets were concentrated SW of the colony 40-75 km offshore and parallel to, but 35 -50 km beyond the shelf break in deep water (1200-2000 m). Birds did not fly farther out to sea to where prey was five times more abundant when N. cristatus could be found at lower abundance levels, closer to the colony. In 2001, N. cristatus were virtually absent at the deep-water stations, likely as a result of massive salp (family Salpidae) aggregations which may have consumed and displaced the seabirds' preferred prey. We demonstrate that while birds were still able to locate and provision chicks with N. cristatus in 2001, they had to forage farther away from the colony in order to do so. Our telemetry results are generally consistent with analyses of at-sea distributions of Cassin's Auklets derived from ship-board surveys (1990-2010) both of which have contributed to the design of the proposed Scott Islands marine National Wildlife Area, the first of its kind in Canada.

  20. Zooplankton associations and environmental factors in Ogunpa and Ona rivers, Nigeria

    Directory of Open Access Journals (Sweden)

    Gbemisola A. Akin-Oriola

    2003-06-01

    Full Text Available Zooplankton abundance, composition and environmental parameters were monitored in two tropical rivers over a twenty month period. The data was subjected to cluster, factor and correlation analysis to determine the grouping pattern of zooplankton and their relationship to environmental parameters. Environmental factors in Ogunpa and Ona rivers -included buffering capacity, trace metal ions, pH-temperature/ transparency- were primarily influenced by rainfall. The dominance of the Rotifera in both rivers was attributed to their short developmental rate and fish predation on larger zooplankton. Two groups of associations were identified in each river - a commonly occurring species group exhibiting strong homogenous correlation with environmental factors and a predominant group exhibiting weak correlation with environmental factors and whose abundance / composition may be defined by biotic factors.La abundancia, y composición del zooplancton, y parámetros ambientales fueron monitoreados en dos ríos tropicales durante un período de doce meses. Los datos fueron sometidos a análisis de agrupaciones, de factores y de correlación para determinar los patrones de agrupamiento del zooplancton y sus relaciones con parámetros ambientales. Los factores ambientales en los ríos Ogunpa y Ona, incluidos la capacidad tampón, iones metálicos traza, pH-temperatura/ transparencia, fueron influenciados principalmente por la lluvia. La dominancia de los Rotíferos en ambos ríos fue atribuida a su corta tasa de desarrollo y a la depredación del zooplancton grande por peces. Dos grupos de asociaciones fueron identificadas en cada río - la presencia de un grupo común de especies que exhiben una fuerte y homogénea correlación con factores ambientales y un grupo predominante que exhibe una débil correlación con factores ambientales y cuya abundancia / composición que podría estar definida por factores bióticos.

  1. A Functional Approach to Zooplankton Communities in Mountain Lakes Stocked With Non-Native Sportfish Under a Changing Climate

    Science.gov (United States)

    Redmond, Laura E.; Loewen, Charlie J. G.; Vinebrooke, Rolf D.

    2018-03-01

    Cumulative impacts of multiple stressors on freshwater biodiversity and ecosystem function likely increase with elevation, thereby possibly placing alpine communities at greatest risk. Here, consideration of species traits enables stressor effects on taxonomic composition to be translated into potential functional impacts. We analyzed data for 47 taxa across 137 mountain lakes and ponds spanning large latitudinal (491 km) and elevational (1,399 m) gradients in western Canada, to assess regional and local factors of the taxonomic composition and functional structure of zooplankton communities. Multivariate community analyses revealed that small body size, clonal reproduction via parthenogenesis, and lack of pigmentation were species traits associated with both introduced non-native sportfish and also environmental conditions reflecting a warmer and drier climate—namely higher water temperatures, shallower water depths, and more chemically concentrated water. Thus, historical introductions of sportfish appear to have potentially induced greater tolerance in zooplankton communities of future climatic warming, especially in previously fishless alpine lakes. Although alpine lake communities occupied a relatively small functional space (i.e., low functional diversity), they were contained within the broader regional functional structure. Therefore, our findings point to the importance of dispersal by lower montane species to the future functional stability of alpine communities.

  2. Import and export fluxes of macrozooplankton are taxa- and season-dependent at Jiuduansha marsh, Yangtze River estuary

    Science.gov (United States)

    Qin, Haiming; Sheng, Qiang; Chu, Tianjiang; Wang, Sikai; Wu, Jihua

    2015-09-01

    Macrozooplankton may play important roles in influencing nutrient exchange between salt marsh and nearby estuarine ecosystems through predator-prey interactions and their transport by tidal flows. In this study, macrozooplankton transport through year-round monthly sampling was investigated in a salt marsh creek of the Yangtze River estuary. Twenty-one orders of macrozooplankton were captured. Calanoida and Decapoda were dominant and numerically comprised 59.59% and 37.59% respectively of the total captured macrozooplankton throughout the year. Decapoda mainly occurred in April, May and June. In other months, the Calanoida contributed over 90% of the total individuals. The annual Ferrari index (I) for total individual number of macrozooplankton was 0.27, which generally supports the viewpoint that salt marshes are sources of zooplankton. The salt marsh was mainly a source for decapods and mysids, possibly because of larval release in their breeding seasons. The marsh was also a source for amphipods, probably because some benthic forms became transient planktonic forms during tidal water flushing. Copepods and fish larvae exhibited net import into the salt marsh, which may result from predation from salt marsh settlers or retention in the salt marsh. Monthly Ferrari index (I) estimations revealed that the role of the salt marsh as a sink or source of macrozooplankton was time-dependent, which is related to the life history of animals. This study showed that whether the salt marsh zooplankton act as energy importers or exporters is group/taxa-dependent and time-dependent.

  3. Zooplankton of the southwest coast of India: abundance, composition, temporal and spatial variability in 1987

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.; Ramaiah, Neelam; Achuthankutty, C.T.

    loop. Distinct coastal and offshore communities among copepods were discernible. Their distributions did not show much change among seasons indicating an ability to maintain their positions in the preferred niches. Niche-partitioning among congeners...

  4. Changes in the abundance and composition of zooplankton from the ports of Mumbai, India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.; Venkat, K.; Anil, A.C.

    in each of the earlier sampling occasions. The reports of 1940’s and 1960’s used ordinary surface tow net made of organdi cloth (Bal and Pradhan, 1952; Pillai, 1968). Data from the 1970’s indicates the use of Heron-Tranter (HT) net having a mouth... area of 0.25 m 2 with a TSK flow meter and a mesh size of 200 µm (Gajbhiye and Desai, 1981). In 1980’s, though the Heron-Tranter (HT) net was used but with a mesh size of 300 µm (Gajbhiye et al., 1984 a and b). In the present investigation we...

  5. Biochemical composition of zooplankton from the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Rao, T.S.S.; Matondkar, S.G.P.

    Protein was the dominant constituent in mixed zooplankton major planktonic groups and some common species collected from the Andaman Sea. Overall mean values, calculated as a percentage of dry weight, were 45,14 protein, 10.6 lipid, 4.2 carbohydrate...

  6. Zooplankton community structure and dynamics during the transition ...

    African Journals Online (AJOL)

    This study investigates the zooplankton community structure and dynamics of Kufena Rock Pool during the transition from dry season (March to April) to rainy season (May to June) in Zaria, Nigeria. Physicochemical parameters such as temperature, hydrogen ion concentration, electrical conductivity and total dissolved ...

  7. Meso-zooplankton movement through the newly constructed Mfolozi ...

    African Journals Online (AJOL)

    Results show that the beach spillway has facilitated recruitment into St Lucia from the ocean and the Mfolozi River. Further research is needed to ascertain what effect this recruitment has on long-term zooplankton community structure. Key words: iSimangaliso Wetland Park, relinkage, Mfolozi channel, ebb and flood tides, ...

  8. Aging of microplastics promotes their ingestion by marine zooplankton

    NARCIS (Netherlands)

    Vroom, Renske J.E.; Koelmans, Bart; Besseling, Ellen

    2017-01-01

    Microplastics (<5 mm) are ubiquitous in the marine environment and are ingested by zooplankton with possible negative effects on survival, feeding, and fecundity. The majority of laboratory studies has used new and pristine microplastics to test their impacts, while aging processes such as

  9. Studies on the distribution of gelatinous zooplankton in the ...

    African Journals Online (AJOL)

    spamer

    boundary to the system (Agenbag and Shannon 1988,. Largier and Boyd 2001), it is not considered to have a profound influence on the specific composition of regional zooplankton (Gibbons et al. 1995, Gibbons and Thibault-Botha 2002, but see Barange et al. 1992,. Emanuel et al. 1992). Indeed, it has been suggested.

  10. Effect of pig dung fertilizer on zooplankton production

    African Journals Online (AJOL)

    SARAH

    2014-12-29

    Dec 29, 2014 ... Key-words: pig dung, fertilization, zooplankton production. ... an already widespread practice in many Asian countries (fukusho, et al., ..... Elsevier Scientific Publishing Company,. New York ... Effect on Water Quality, pond productivity and. Growth of ... McQueen DJ, Johannes MRS, Post JR, Stewart TJ, Lean.

  11. Potential acidification impacts on zooplankton in CCS leakage scenarios

    International Nuclear Information System (INIS)

    Halsband, Claudia; Kurihara, Haruko

    2013-01-01

    Highlights: • Effects of CCS techniques and ocean acidification on zooplankton are under-studied. • Vulnerable zooplankton are meso-, bathypelagic and vertically migrating species. • Impacts include impaired calcification, reproduction, development and survival. • Need for modelling studies combining physico-chemical with ecological impacts. -- Abstract: Carbon capture and storage (CCS) technologies involve localized acidification of significant volumes of seawater, inhabited mainly by planktonic species. Knowledge on potential impacts of these techniques on the survival and physiology of zooplankton, and subsequent consequences for ecosystem health in targeted areas, is scarce. The recent literature has a focus on anthropogenic greenhouse gas emissions into the atmosphere, leading to enhanced absorption of CO 2 by the oceans and a lowered seawater pH, termed ocean acidification. These studies explore the effects of changes in seawater chemistry, as predicted by climate models for the end of this century, on marine biota. Early studies have used unrealistically severe CO 2 /pH values in this context, but are relevant for CCS leakage scenarios. Little studied meso- and bathypelagic species of the deep sea may be especially vulnerable, as well as vertically migrating zooplankton, which require significant residence times at great depths as part of their life cycle

  12. Pilot Study on Potential Impacts of Fisheries-Induced Changes in Zooplankton Mortality on Marine Biogeochemistry

    Science.gov (United States)

    Getzlaff, Julia; Oschlies, Andreas

    2017-11-01

    In this pilot study we link the yield of industrial fisheries to changes in the zooplankton mortality in an idealized way accounting for different target species (planktivorous fish—decreased zooplankton mortality; large predators—increased zooplankton mortality). This indirect approach is used in a global coupled biogeochemistry circulation model to estimate the range of the potential impact of industrial fisheries on marine biogeochemistry. The simulated globally integrated response on phytoplankton and primary production is in line with expectations—a high (low) zooplankton mortality results in a decrease (increase) of zooplankton and an increase (decrease) of phytoplankton. In contrast, the local response of zooplankton and phytoplankton depends on the region under consideration: In nutrient-limited regions, an increase (decrease) in zooplankton mortality leads to a decrease (increase) in both zooplankton and phytoplankton biomass. In contrast, in nutrient-replete regions, such as upwelling regions, we find an opposing response: an increase (decrease) of the zooplankton mortality leads to an increase (decrease) in both zooplankton and phytoplankton biomass. The results are further evaluated by relating the potential fisheries-induced changes in zooplankton mortality to those driven by CO2 emissions in a business-as-usual 21st century emission scenario. In our idealized case, the potential fisheries-induced impact can be of similar size as warming-induced changes in marine biogeochemistry.

  13. Zooplankton associated with the oxygen minimum zone system in the northern upwelling region of Chile during March 2000

    Science.gov (United States)

    Escribano, Ruben; Hidalgo, Pamela; Krautz, Cristina

    2009-07-01

    Zooplankton in the coastal upwelling region off northern Chile may play a significant biogeochemical role by promoting carbon flux into the subsurface OMZ (oxygen minimum zone). This work identifies the dominant zooplankton species inhabiting the area influenced by the OMZ in March 2000 off Iquique (20°S, northern Chile). Abundance and vertical distribution studies revealed 17 copepod and 9 euphausiid species distributed between the surface and 600 m at four stations sampled both by day and by night. Some abundant species remained in the well-oxygenated upper layer (30 m), with no evidence of diel vertical migration, apparently restricted by a shallow (40-60 m) oxycline. Other species, however, were found closely associated with the OMZ. The large-sized copepod Eucalanus inermis was found below the oxycline and performed diel vertical migrations into the OMZ, whereas the very abundant Euphausia mucronata performed extensive diel vertical migrations between the surface waters and the core of the OMZ (200 m), even crossing it. A complete assessment of copepods and euphausiids revealed that the whole sampled water column (0-600 m) is occupied by distinct species having well-defined habitats, some of them within the OMZ. Ontogenetic migrations were evident in Eucalanidae and E. mucronata. Estimates of species biomass showed a substantial (>75% of total zooplankton biomass) daily exchange of C between the photic layer and the OMZ. Both E. inermis and E. mucronata can actively exchange about 37.8 g C m -2 d -1 between the upper well-oxygenated (0-60 m) layer and the deeper (60-600 m) OMZ layer. This migrant biomass may contribute about 7.2 g C m -2 d -1 to the OMZ system through respiration, mortality, and production of fecal pellets within the OMZ. This movement of zooplankton in and out of the OMZ, mainly as a result of the migratory behavior of E. mucronata, suggests a very efficient mechanism for introducing large amounts of freshly produced carbon into the OMZ

  14. Ambiguous taxa: Effects on the characterization and interpretation of invertebrate assemblages

    Science.gov (United States)

    Cuffney, T.F.; Bilger, Michael D.; Haigler, A.M.

    2007-01-01

    Damaged and immature specimens often result in macroinvertebrate data that contain ambiguous parent-child pairs (i.e., abundances associated with multiple related levels of the taxonomic hierarchy such as Baetis pluto and the associated ambiguous parent Baetis sp.). The choice of method used to resolve ambiguous parent-child pairs may have a very large effect on the characterization of invertebrate assemblages and the interpretation of responses to environmental change because very large proportions of taxa richness (73-78%) and abundance (79-91%) can be associated with ambiguous parents. To address this issue, we examined 16 variations of 4 basic methods for resolving ambiguous taxa: RPKC (remove parent, keep child), MCWP (merge child with parent), RPMC (remove parent or merge child with parent depending on their abundances), and DPAC (distribute parents among children). The choice of method strongly affected assemblage structure, assemblage characteristics (e.g., metrics), and the ability to detect responses along environmental (urbanization) gradients. All methods except MCWP produced acceptable results when used consistently within a study. However, the assemblage characteristics (e.g., values of assemblage metrics) differed widely depending on the method used, and data should not be combined unless the methods used to resolve ambiguous taxa are well documented and are known to be comparable. The suitability of the methods was evaluated and compared on the basis of 13 criteria that considered conservation of taxa richness and abundance, consistency among samples, methods, and studies, and effects on the interpretation of the data. Methods RPMC and DPAC had the highest suitability scores regardless of whether ambiguous taxa were resolved for each sample separately or for a group of samples. Method MCWP gave consistently poor results. Methods MCWP and DPAC approximate the use of family-level identifications and operational taxonomic units (OTU), respectively. Our

  15. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne

    2017-09-14

    Sedimentation, nutrients and metal loading to coastal environments are increasing, associated with urbanization and global warming, hence there is a growing need to predict ecological responses to such change. Using a regression technique we predicted how maximum abundance of 20 macrobenthic taxa and 22 functional traits separately and interactively responded to these key stressors. The abundance of most taxa declined in response to sedimentation and metal loading while a unimodal response was often associated with nutrient loading. Optimum abundances for both taxa and traits occurred at relatively low stressor levels, highlighting the vulnerability of estuaries to increasing stressor loads. Individual taxa were more susceptible to stress than traits, suggesting that functional traits may be less sensitive for detecting changes in ecosystem health. Multiplicative effects were more common than additive interactions. The observed sensitivity of most taxa to increasing sedimentation and metal loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  16. Plankton communities and summertime declines in algal abundance associated with low dissolved oxygen in the Tualatin River, Oregon

    Science.gov (United States)

    Carpenter, Kurt D.; Rounds, Stewart A.

    2013-01-01

    . Meteorological, streamflow, turbidity, water temperature, and conductance conditions in the Tualatin River during the 2006–08 summer seasons were not atypical. Natural flow comprised the majority (70–80 percent) of flow each year during spring, but then reduced to 38–40 percent during midsummer when WWTF effluent—which contributed as much as 36 percent—and flow augmentation releases comprised a greater fraction of the flow. Summer 2008 was unusual, however, in the prolonged influence from the Wapato Lake agricultural area near Gaston in the upper part of the basin. The previous winter flooding and levee breach at Wapato Lake caused a much greater area of inundation. As a result, drainage from this area continued into July, much later than normal. A subsequent algal bloom in Wapato Lake then seeded the upper Tualatin River, and this drainage had a profound effect on the downstream plankton community. A large blue-green algae bloom developed—the largest in recent memory—prompting a public health advisory for recreational contact for about two weeks. Algal growths and surface blooms are a common feature of the Tualatin River. Most of the dominant algae have growth forms and morphologies that are well suited for planktonic life, employing spines and gas vacuoles to resist settling, forming colonies, and producing mucilage (or toxins) to resist zooplankton grazing. In 2006–08, 143 algal taxa were identified in 117 main-stem samples; diatoms and green algae were more diverse than blue-green, golden, and cryptophyte algae, although these later groups sometimes dominated the overall volumetric abundance (biovolume). The most frequently occurring taxa, occurring in 97–99 percent of samples, were flagellated cryptophytes Cryptomonas erosa and Rhodomonas minuta. Other important algal taxa included centric diatoms Stephanodiscus, Cyclotella, and Melosira species and colonial green algae Scenedesmus and Actinastrum. These taxa comprised the majority of the algal biovolume

  17. Estuarine and marine diets of out-migrating Chinook Salmon smolts in relation to local zooplankton populations, including harmful blooms

    Science.gov (United States)

    Chittenden, C. M.; Sweeting, R.; Neville, C. M.; Young, K.; Galbraith, M.; Carmack, E.; Vagle, S.; Dempsey, M.; Eert, J.; Beamish, R. J.

    2018-01-01

    Changes in food availability during the early marine phase of wild Chinook Salmon (O. tshawytscha) are being investigated as a cause of their recent declines in the Salish Sea. The marine survival of hatchery smolts, in particular, has been poor. This part of the Salish Sea Marine Survival Project examined the diet of young out-migrating Chinook Salmon for four consecutive years in the Cowichan River estuary and in Cowichan Bay, British Columbia, Canada. Local zooplankton communities were monitored during the final year of the study in the Cowichan River estuary, Cowichan Bay, and eastward to the Salish Sea to better understand the bottom-up processes that may be affecting Chinook Salmon survival. Rearing environment affected body size, diet, and distribution in the study area. Clipped smolts (hatchery-reared) were larger than the unclipped smolts (primarily naturally-reared), ate larger prey, spent very little time in the estuary, and disappeared from the bay earlier, likely due to emigration or mortality. Their larger body size may be a disadvantage for hatchery smolts if it necessitates their leaving the estuary prematurely to meet energy needs; the onset of piscivory began at a forklength of approximately 74 mm, which was less than the average forklength of the clipped fish in this study. The primary zooplankton bloom occurred during the last week of April/first week of May 2013, whereas the main release of hatchery-reared Chinook Salmon smolts occurs each year in mid-May-this timing mismatch may reduce their survival. Gut fullness was correlated with zooplankton biomass; however, both the clipped and unclipped smolts were not observed in the bay until the bloom of harmful Noctiluca was finished-20 days after the maximum recorded zooplankton abundance. Jellyfish medusa flourished in nearshore areas, becoming less prevalent towards the deeper waters of the Salish Sea. The sizable presence of Noctiluca and jellyfish in the zooplankton blooms may be repelling

  18. From the epipelagic zone to the abyss: Trophic structure at two seamounts in the subtropical and tropical Eastern Atlantic - Part I zooplankton and micronekton

    Science.gov (United States)

    Denda, Anneke; Stefanowitsch, Benjamin; Christiansen, Bernd

    2017-12-01

    Specific mechanisms, driving trophic interactions within the pelagic community may be highly variable in different seamount systems. This study investigated the trophic structure of zooplankton and micronekton above and around Ampère and Senghor, two shallow seamounts in the subtropical and tropical Eastern Atlantic, and over the adjacent abyssal plains. For the identification of food sources and trophic positions stable isotope ratios (δ13C and δ15N) were used. δ13C ranged from -24.7‰ to -15.0‰ and δ15N covered a total range of 0.9-15.9‰. Based on epipelagic particulate organic matter, zooplankton and micronekton usually occupied the 1st-3rd trophic level, including herbivorous, omnivorous and carnivorous taxa. δ13C and δ15N values were generally lower in zooplankton and micronekton of the subtropical waters as compared to the tropical region, due to the differing nutrient availability and phytoplankton communities. Correlations between δ13C and δ15N values of particulate organic matter, zooplankton, micronekton and benthopelagic fishes suggest a linear food chain based on a single energy source from primary production for Ampère Seamount, but no evidence was found for an autochthonus seamount production as compared to the open ocean reference site. Between Senghor Seamount and the open ocean δ13C signatures indicate that hydrodynamic effects at seamounts may modify the energy supply at times, but evidence for a seamount effect on the trophic structure of the pelagic communities was weak, which supports the assumption that seamount communities rely to a large extent on advected food sources.

  19. Annual variation in neustonic micro- and meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean-Corsica).

    Science.gov (United States)

    Collignon, Amandine; Hecq, Jean-Henri; Galgani, François; Collard, France; Goffart, Anne

    2014-02-15

    The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size classes, small microplastics (0.2-2mm), large microplastics (2-5mm) and mesoplastics (5-10mm). 74% of the 38 samples contained plastic particles of varying composition: e.g. filaments, polystyrene, thin plastic films. An average concentration of 6.2 particles/100 m(2) was observed. The highest abundance values (69 particles/100 m(2)) observed occurred during periods of low offshore wind conditions. These values rose in the same order of magnitude as in previous studies in the North Western Mediterranean. The relationships between the abundance values of the size classes between zooplankton and plastic particles were then examined. The ratio for the intermediate size class (2-5mm) reached 2.73. This would suggest a potential confusion for predators regarding planktonic prey of this size class. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Intra and inter-annual structure of zooplankton communities in floodplain lakes: a long-term ecological research study

    Directory of Open Access Journals (Sweden)

    Nadson R. Simões

    2012-12-01

    Full Text Available Water flow management has significantly changed the natural dynamic of floods, which are responsible for the structure and dynamic of aquatic communities in river-floodplain systems. With the aim to elaborate a conceptual framework that describes the main ecological factors associated with zooplankton community structure in the Upper Paraná River, we investigated the mechanisms that regulate the communities structure and their response to inter-annual and hydro-sedimentological variations in the floodplain and the biological factors associated with species abundance in those communities. For this we conducted samplings every six months (potamophase in March and limnophase in September to characterize intra and inter-annual variations in community structure between 2000 and 2008. The intra-annual differences on the species richness, abundance, Shannon diversity index, and evenness, were conducted using Bayesian procedures to show probabilistic predictions of the data fit to main variation sources. Non-metric multi-dimensional scaling (NMDS, multi-response permutation procedure (MRPP, and indicator species analysis (IndVal were run to assess and characterize the seasonality of the community structure. During high water (potamophase, hydrologic connectivity favoured exchange and dispersal of species in some lakes, increasing local diversity; during low water (limnophase, higher local productivity favoured opportunistic taxa, increasing species dominance and decreasing local diversity. Food resources and density of small-size fish were biological factors associated with the seasonal dynamic of the zooplankton community; these factors were dependent on hydrosedimentological phase (potamophase or limnophase. Water levels and limnological modifications related to water flow management have promoted replacement and impoverishment of aquatic biota in affected lakes and have indicated the ecological importance of a natural dynamic flood, which displays

  1. Pyrosequencing detects human and animal pathogenic taxa in the grapevine endosphere.

    Science.gov (United States)

    Yousaf, Sohail; Bulgari, Daniela; Bergna, Alessandro; Pancher, Michael; Quaglino, Fabio; Casati, Paola; Campisano, Andrea

    2014-01-01

    Generally, plants are not considered as hosts for human and animal pathogens (HAP). The recent produce-associated outbreaks of food-borne diseases have drawn attention toward significant deficiencies in our understanding of the ecology of HAP, and their potential for interkingdom transfer. To examine the association of microorganisms classified as HAP with plants, we surveyed the presence and distribution of HAP bacterial taxa (henceforth HAPT, for brevity's sake) in the endosphere of grapevine (Vitis vinifera L.) both in the plant stems and leaves. An enrichment protocol was used on leaves to detect taxa with very low abundance in undisturbed tissues. We used pyrosequencing and phylogenetic analyses of the 16S rDNA gene. We identified several HAPT, and focused on four genera (Propionibacterium, Staphylococcus, Clostridium, and Burkholderia). The majority of the bacterial sequences in the genus Propionibacterium, from grapevine leaf and stem, were identified as P. acnes. Clostridia were detected in leaves and stems, but their number was much higher in leaves after enrichment. HAPT were indentified both in leaves and wood of grapevines. This depicts the ability of these taxa to be internalized within plant tissues and maintain their population levels in a variety of environments. Our analysis highlighted the presence of HAPT in the grapevine endosphere and unexpected occurrence of these bacterial taxa in this atypical environment.

  2. Molecular Quantification of Zooplankton Gut Content: The Case For qPCR

    Science.gov (United States)

    Frischer, M. E.; Walters, T. L.; Gibson, D. M.; Nejstgaard, J. C.; Troedsson, C.

    2016-02-01

    The ability to obtain information about feeding selectivity and rates in situ for zooplankton is vital for understanding the mechanisms structuring marine ecosystems. However, directly estimating feeding selection and rates of zooplankton, without bias, associated with culturing conditions has been notoriously difficult. A potential approach for addressing this problem is to target prey-specific DNA as a marker for prey ingestion and selection. In this study we report the development of a differential length amplification quantitative PCR (dla-qPCR) assay targeting the 18S rRNA gene to validate the use of a DNA-based approach to quantify consumption of specific plankton prey by the pelagic tunicate (doliolid) Dolioletta gegenbauri. Compared to copepods and other marine animals, the digestion of prey genomic DNA inside the gut of doliolids is low. This method minimizes potential underestimations, and therefore allows prey DNA to be used as an effective indicator of prey consumption. We also present an initial application of a qPCR-assay to estimate consumption of specific prey species on the southeastern continental shelf of the U.S., where doliolids stochastically bloom in response to upwelling events. Estimated feeding rates, based on qPCR, were in the same range as those estimated from clearance rates in laboratory feeding studies. In the field, consumption of specific prey, including the centric diatom Thalassiosira spp. was detected in the gut of wild caught D. gegenbauri at the levels consistent with their abundance in the water column at the time of collection. Thus, both experimental and field investigations support the hypothesis that a qPCR approach will be useful for the quantitative investigation of the in situ diet of D. gegenbauri without introduced bias' associated with cultivation.

  3. Crustacean zooplankton release copious amounts of dissolved organic matter as taurine in the ocean.

    Science.gov (United States)

    Clifford, Elisabeth L; Hansell, Dennis A; Varela, Marta M; Nieto-Cid, Mar; Herndl, Gerhard J; Sintes, Eva

    2017-11-01

    Taurine (Tau), an amino acid-like compound, is present in almost all marine metazoans including crustacean zooplankton. It plays an important physiological role in these organisms and is released into the ambient water throughout their life cycle. However, limited information is available on the release rates by marine organisms, the concentrations and turnover of Tau in the ocean. We determined dissolved free Tau concentrations throughout the water column and its release by abundant crustacean mesozooplankton at two open ocean sites (Gulf of Alaska and North Atlantic). At both locations, the concentrations of dissolved free Tau were in the low nM range (up to 15.7 nM) in epipelagic waters, declining sharply in the mesopelagic to about 0.2 nM and remaining fairly stable throughout the bathypelagic waters. Pacific amphipod-copepod assemblages exhibited lower dissolved free Tau release rates per unit biomass (0.8 ± 0.4 μmol g -1 C-biomass h -1 ) than Atlantic copepods (ranging between 1.3 ± 0.4 μmol g -1 C-biomass h -1 and 9.5 ± 2.1 μmol g -1 C-biomass h -1 ), in agreement with the well-documented inverse relationship between biomass-normalized excretion rates and body size. Our results indicate that crustacean zooplankton might contribute significantly to the dissolved organic matter flux in marine ecosystems via dissolved free Tau release. Based on the release rates and assuming steady state dissolved free Tau concentrations, turnover times of dissolved free Tau range from 0.05 d to 2.3 d in the upper water column and are therefore similar to those of dissolved free amino acids. This rapid turnover indicates that dissolved free Tau is efficiently consumed in oceanic waters, most likely by heterotrophic bacteria.

  4. Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency

    OpenAIRE

    Taipale, Sami J.; Galloway, Aaron W. E.; Aalto, Sanni L.; Kahilainen, Kimmo K.; Strandberg, Ursula; Kankaala, Paula

    2016-01-01

    Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terr...

  5. Next generation sequencing reveals the hidden diversity of zooplankton assemblages.

    Directory of Open Access Journals (Sweden)

    Penelope K Lindeque

    Full Text Available BACKGROUND: Zooplankton play an important role in our oceans, in biogeochemical cycling and providing a food source for commercially important fish larvae. However, difficulties in correctly identifying zooplankton hinder our understanding of their roles in marine ecosystem functioning, and can prevent detection of long term changes in their community structure. The advent of massively parallel next generation sequencing technology allows DNA sequence data to be recovered directly from whole community samples. Here we assess the ability of such sequencing to quantify richness and diversity of a mixed zooplankton assemblage from a productive time series site in the Western English Channel. METHODOLOGY/PRINCIPLE FINDINGS: Plankton net hauls (200 µm were taken at the Western Channel Observatory station L4 in September 2010 and January 2011. These samples were analysed by microscopy and metagenetic analysis of the 18S nuclear small subunit ribosomal RNA gene using the 454 pyrosequencing platform. Following quality control a total of 419,041 sequences were obtained for all samples. The sequences clustered into 205 operational taxonomic units using a 97% similarity cut-off. Allocation of taxonomy by comparison with the National Centre for Biotechnology Information database identified 135 OTUs to species level, 11 to genus level and 1 to order, <2.5% of sequences were classified as unknowns. By comparison a skilled microscopic analyst was able to routinely enumerate only 58 taxonomic groups. CONCLUSIONS: Metagenetics reveals a previously hidden taxonomic richness, especially for Copepoda and hard-to-identify meroplankton such as Bivalvia, Gastropoda and Polychaeta. It also reveals rare species and parasites. We conclude that Next Generation Sequencing of 18S amplicons is a powerful tool for elucidating the true diversity and species richness of zooplankton communities. While this approach allows for broad diversity assessments of plankton it may

  6. A stochastic analysis for a phytoplankton-zooplankton model

    International Nuclear Information System (INIS)

    Ge, G; Wang, H-L; Xu, J

    2008-01-01

    A simple phytoplankton-zooplankton nonlinear dynamical model was proposed to study the coexistence of all the species and a Hopf bifurcation was observed. In order to study the effect of environmental robustness on this system, we have stochastically perturbed the system with respect to white noise around its positive interior equilibrium. We have observed that the system remains stochastically stable around the positive equilibrium for same parametric values in the deterministic situation

  7. Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency.

    Science.gov (United States)

    Taipale, Sami J; Galloway, Aaron W E; Aalto, Sanni L; Kahilainen, Kimmo K; Strandberg, Ursula; Kankaala, Paula

    2016-08-11

    Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous zooplankton is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was <28% of the assimilated carbon. Taken collectively, the incorporation of terrestrial carbon into zooplankton was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton.

  8. Zooplankton community of Parnaíba River, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Ludmilla Cavalcanti Antunes Lucena

    2015-03-01

    Full Text Available Aim:The objective of the present work is to present a list of species of zooplankton (Rotifera, Cladocera and Copepoda from the Parnaíba River. Additionally, we provide comments on their distribution along the river, and between dry and wet seasons.MethodsZooplankton was collected with a plankton net (60 µm mesh and concentrated into a volume of 80 mL for further analysis, during the dry (October 2010 and wet (April 2011 seasons. Sampling was restricted to the marginal areas at depths between 80 and 150 cm.ResultsA total of 132 species was recorded among the three zooplankton groups studied. During the dry season a total of 82 species was registered and 102 species was registered for the wet season. Rotifera contributed with 66.7% of the species, followed by Cladocera (26.5% and Copepoda (6.8%.ConclusionsThe richness of species observed was high compared to other large rivers in Brazil. In the context of current policies for water management and river diversions in northeastern Brazil, the present study highlights the importance of this river system for biodiversity conservation.

  9. SEAPODYM-LTL: a parsimonious zooplankton dynamic biomass model

    Science.gov (United States)

    Conchon, Anna; Lehodey, Patrick; Gehlen, Marion; Titaud, Olivier; Senina, Inna; Séférian, Roland

    2017-04-01

    Mesozooplankton organisms are of critical importance for the understanding of early life history of most fish stocks, as well as the nutrient cycles in the ocean. Ongoing climate change and the need for improved approaches to the management of living marine resources has driven recent advances in zooplankton modelling. The classical modeling approach tends to describe the whole biogeochemical and plankton cycle with increasing complexity. We propose here a different and parsimonious zooplankton dynamic biomass model (SEAPODYM-LTL) that is cost efficient and can be advantageously coupled with primary production estimated either from satellite derived ocean color data or biogeochemical models. In addition, the adjoint code of the model is developed allowing a robust optimization approach for estimating the few parameters of the model. In this study, we run the first optimization experiments using a global database of climatological zooplankton biomass data and we make a comparative analysis to assess the importance of resolution and primary production inputs on model fit to observations. We also compare SEAPODYM-LTL outputs to those produced by a more complex biogeochemical model (PISCES) but sharing the same physical forcings.

  10. The characteristic of a zooplankton in the contaminated bottom stream of the Pripyat' river and backwaters

    International Nuclear Information System (INIS)

    Zarubaw, A.I.; Malatkow, D.V.

    1994-01-01

    The researches of zooplankton are conducted on two stations on the Pripyat' river, but also on two backwaters which are in the Chernobyl NPP contamination zone. The rotifera is dominant group of zooplankton. Their quantity is more than 10 samples/litter. An absolute and relative fertility of rotifera is determined. It is established an structural and functional reorganization of the rotifera dominant complexes occurs. Any influence of contamination on a zooplankton condition is not found out. 5 refs., 2 tabs., 2 figs

  11. Towards stressor-specific macroinvertebrate indices: Which traits and taxonomic groups are associated with vulnerable and tolerant taxa?

    Science.gov (United States)

    Berger, Elisabeth; Haase, Peter; Schäfer, Ralf B; Sundermann, Andrea

    2018-04-01

    Monitoring of macroinvertebrate communities is frequently used to define the ecological health status of rivers. Ideally, biomonitoring should also give an indication on the major stressors acting on the macroinvertebrate communities supporting the selection of appropriate management measures. However, most indices are affected by more than one stressor. Biological traits (e.g. size, generation time, reproduction) could potentially lead to more stressor-specific indices. However, such an approach has rarely been tested. In this study we classify 324 macroinvertebrate taxa as vulnerable (decreasing abundances) or tolerant (increasing abundances) along 21 environmental gradients (i.e. nutrients, major ions, oxygen and micropollutants) from 422 monitoring sites in Germany using Threshold Indicator Taxa Analysis (TITAN). Subsequently, we investigate which biological traits and taxonomic groups are associated with taxa classified as vulnerable or tolerant with regard to specific gradients. The response of most taxa towards different gradients was similar and especially high for correlated gradients. Traits associated with vulnerable taxa across most gradients included: larval aquatic life stages, isolated cemented eggs, reproductive cycle per year macrophytes, microphytes, silt or mud and a body size >2-4cm. Our results question whether stressor-specific indices based on macroinvertebrate assemblages can be achieved using single traits, because we observed that similar taxa responded to different gradients and also similar traits were associated with vulnerable and tolerant taxa across a variety of water quality gradients. Future studies should examine whether combinations of traits focusing on specific taxonomic groups achieve higher stressor specificity. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Metazoan meiofauna in deep-sea canyons and adjacent open slopes: A large-scale comparison with focus on the rare taxa

    Science.gov (United States)

    Bianchelli, S.; Gambi, C.; Zeppilli, D.; Danovaro, R.

    2010-03-01

    Metazoan meiofaunal abundance, total biomass, nematode size and the richness of taxa were investigated along bathymetric gradients (from the shelf break down to ca. 5000-m depth) in six submarine canyons and on five adjacent open slopes of three deep-sea regions. The investigated areas were distributed along >2500 km, on the Portuguese to the Catalan and South Adriatic margins. The Portuguese and Catalan margins displayed the highest abundances, biomass and richness of taxa, while the lowest values were observed in the Central Mediterranean Sea. The comparison between canyons and the nearby open slopes showed the lack of significant differences in terms of meiofaunal abundance and biomass at any sampling depth. In most canyons and on most slopes, meiofaunal variables did not display consistent bathymetric patterns. Conversely, we found that the different topographic features were apparently responsible for significant differences in the abundance and distribution of the rare meiofaunal taxa (i.e. taxa accounting for Priapulida, Holothuroidea, Ascidiacea and Cnidaria, were encountered exclusively on open slopes, while others (including the Tanaidacea and Echinodea larvae) were found exclusively in canyons sediments. Results reported here indicate that, at large spatial scales, differences in deep-sea meiofaunal abundance and biomass are not only controlled by the available food sources, but also by the region or habitat specific topographic features, which apparently play a key role in the distribution of rare benthic taxa.

  13. Nutrient regeneration by zooplankton during a red tide off Peru, with notes on biomass and species composition of zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.L.

    1978-01-01

    During March and April 1976, a red tide, dominated by the dinoflagallate Gymnodinium splendens Lebour, developed in the vicinity of 15/sup 0/O6'S and 76/sup 0/31'W off Peru. At the height of the bloom, the euphotic zone was 6 m deep and the chlorophyll a at the surface was 48 ..mu..g 1/sup -1/. A daily collection of zooplankton at 09.00 hrs showed large fluctuations of biomass, from 0.2 to 3.84 g dry weight m/sup -2/ in a water column of 120 m. Copepodids and nauplii dominated the collections. During a period of reduced wind, the adult copepods were a mixture of the species characteristic of the coastal upwelling system and the neritic species associated with more northerly, tropical waters. Nitrogen regeneration by the zooplankton varied with the development of the bloom, the type of zooplankton dominating the experiment, and biomass fluctuations, but never accounted for more than 25% of the nitrogen uptake by phytoplankton.

  14. Zooplankton and zoobenthos of the Mokra Sura river

    Directory of Open Access Journals (Sweden)

    V. Yakovenko

    2017-12-01

    Full Text Available Purpose. To study the spatial distribution of structural and functional indicators of zooplankton and zoobenthos during the period of maximum development of hydrobiocenosis in the contaminated and conditionally clean sites of the Mokra Sura river being under antropogenic pressure. Methodology. During the collection and subsequent laboratory processing of zooplankton and zoobenthos samples, we used the standard conventional hydrobiological methods. In order to rank the studied river sites, we used the combined index of the community state (CICS based on the structural-functional indicators of zoobenthos. Findings. The research results have shown that the species composition of zoobenthos and zooplankton of the Mokra Sura river included many saprobiontic species such as oligochaetes, chironomids and rotifers, which were developed significantly in some sites under the effect of eutrophication and silt accumulation in the presence of anthropogenic pollution. The above-mentioned processes cause inhibition of the life activity of such filter feeders as mollusks and crustaceans being the most powerful zooplanktonic and zoobenthic agents of self-cleaning. The highest numbers of zooplankton and zoobenthos development were recorded in front of the point of the emergency discharge of right-bank sewage water (stimulating effect of organic pollution while the lowest numbers were registered near the tire plant (combined effect of both chemical sewage pollution and silt accumulation. In the «Dnipro - Zaporizhzhia highway» site, low numbers of zooplankton development were the result of silt accumulation, whereas the zoobenthos biomass turned out to be the highest due to the intensive development of oligochaetes. Planktonic saprobiontic rotifers dominated in the site located in front of the sewage discharge whereas bdelloid rotifers dominated in the upstream sites of the river. The dominance of planktonic and benthic saprobiontic rotifers caused the highest

  15. Zooplankton community structure in the presence of low levels of cyanotoxins: a case study in a high altitude tropical reservoir (Valle de Bravo, Mexico

    Directory of Open Access Journals (Sweden)

    Michael A. Figueroa-Sanchez

    2014-02-01

    Full Text Available Valle de Bravo water reservoir in the State of Mexico is being intensively studied since it provides water to about 2,500,000 people living in Mexico City. Cyanobacterial blooms reduce the water quality in this reservoir and this poses health risks. We hypothesize that one of the reasons for these persistent blooms is the dominance of small sized zooplankton throughout the year. Zooplankton samples were collected monthly by filtering 50 L of water from the surface (10-20 cm using a 50 µm mesh and the samples were fixed in 4% formalin in the field. We measured temperature, pH, conductivity, Secchi disk transparency, dissolved oxygen, nitrates and phosphates. The microcystin levels were also quantified. The Secchi depth ranged from 0.86 to 9 m, nitrate levels were low (0.28 to 2.06 mg L-1, while phosphates were in the range of 1 to 14 mg L-1. The temperature varied from 14 to 25 °C. The zooplankton community was represented by 25 species of rotifers Keratella cochlearis had the highest density (840 ind L-1, followed by Polyarthra vulgaris (750 ind L-1. As compared to previous studies where the genus Brachionus was practically absent, we found four brachionid species. Among cladocerans, Bosmina longirostris was the dominant taxa reaching up to 100 ind L-1. Small sized zooplankton (<200 µm dominated throughout the year. The zooplankton biomass in the winter months (December to February was contributed by Daphnia laevis, copepodites and adult copepods. Unlike a decade ago when a dominance by cyanobacteria was recorded, in this study we found that the phytoplankton was dominated by diatoms and chlorophytes with an occasional presence of the cyanobacteria Anabaena spp. and Microcystis spp. The concentration of microcystins ranged from 0.5 to 0.7 µg L-1 and was within the parameters set by the WHO. Carlson’s Trophic State Index and Sladecek’s Brachionus/Trichocera ratio indicated that the reservoir was mesotrophic during the study period.

  16. Zooplankton data collected from zooplankton net casts from RESEARCHER I and other platforms in TOGA Area of Pacific Ocean; 16 March 1968 to 02 July 1970 (NODC Accession 9500141)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton species identities and other data were collected using zooplankton casts in the TOGA Area of Pacific Ocean from RESEARCHER I and other platforms. Data...

  17. Zooplankton data from zooplankton net casts and other instruments in the Delaware Bay and North Atlantic Ocean as part of the Ocean Continental Shelf (OCS - Mid Atlantic) project, 03 November 1976 - 18 November 1977 (NODC Accession 7800340)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts and other instruments in the Delaware Bay and North Atlantic Ocean from November 3, 1976 to November 18,...

  18. The effect of Kingston Harbour outflow on the zooplankton populations of Hellshire, south-east coast, Jamaica

    Science.gov (United States)

    Lindo, Mona K.

    1991-06-01

    Zooplankton sampling was conducted at 16 stations located at the mouth of Kingston Harbour and throughout the Hellshire area from November 1985 to March 1987. Parameters examined included total biomass, total numbers and numbers of numerically important zooplankton species. Maximum values were recorded west of the Harbour mouth (station 1) and these gradually decreased with distance from the Harbour especially at the 'offshore' stations, producing a gradient effect in this area. Mean biomass and abundance for the period sampled ranged from 14 g m -3 and 16 313 individuals m -3 at the western side of the Harbour mouth to 0·4 g m -3 and 172 individuals m -3 at Wreck Reef. Stations within the bays of Hellshire occasionally had values similar to those recorded at the mouth of Kingston Harbour and here there was less evidence of a gradual decline. Considerable monthly fluctuation occurred in these parameters but there was no discernible seasonal pattern. Copepods dominated the population at most stations and the sergestid Lucifer faxoni also proved an important member at the western Harbour mouth station.

  19. Planktivory in the changing Lake Huron zooplankton community: Bythotrephes consumption exceeds that of Mysis and fish

    Science.gov (United States)

    Bunnell, D.B.; Hunter, R. Douglas; Warner, D.M.; Chriscinske, M.A.; Roseman, E.F.

    2011-01-01

    Oligotrophic lakes are generally dominated by calanoid copepods because of their competitive advantage over cladocerans at low prey densities. Planktivory also can alter zooplankton community structure. We sought to understand the role of planktivory in driving recent changes to the zooplankton community of Lake Huron, a large oligotrophic lake on the border of Canada and the United States. We tested the hypothesis that excessive predation by fish (rainbow smelt Osmerus mordax, bloater Coregonus hoyi) and invertebrates (Mysis relicta, Bythotrephes longimanus) had driven observed declines in cladoceran and cyclopoid copepod biomass between 2002 and 2007. We used a field sampling and bioenergetics modelling approach to generate estimates of daily consumption by planktivores at two 91-m depth sites in northern Lake Huron, U.S.A., for each month, May-October 2007. Daily consumption was compared to daily zooplankton production. Bythotrephes was the dominant planktivore and estimated to have eaten 78% of all zooplankton consumed. Bythotrephes consumption exceeded total zooplankton production between July and October. Mysis consumed 19% of all the zooplankton consumed and exceeded zooplankton production in October. Consumption by fish was relatively unimportant - eating only 3% of all zooplankton consumed. Because Bythotrephes was so important, we explored other consumption estimation methods that predict lower Bythotrephes consumption. Under this scenario, Mysis was the most important planktivore, and Bythotrephes consumption exceeded zooplankton production only in August. Our results provide no support for the hypothesis that excessive fish consumption directly contributed to the decline of cladocerans and cyclopoid copepods in Lake Huron. Rather, they highlight the importance of invertebrate planktivores in structuring zooplankton communities, especially for those foods webs that have both Bythotrephes and Mysis. Together, these species occupy the epi-, meta- and

  20. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    Science.gov (United States)

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens, ranged from 0.1-0.25/d and were significantly higher on C vulgaris cultured in liquid fertilizer as compared to the other diets. The growth rates of M. macrocopa ranged from 0.1 to 0.38/d, and were highest with diets of C. vulgaris cultured in Bold medium and S. acutus cultured in fertilizer. Thus, regardless of the culture medium used, the growth rates of the evaluated zooplankton species were higher with Chlorella than with Scenedesmus. The peak population density was highest (2 800ind/mL) for A. fissa fed Chlorella that was cultured on

  1. Impact of chromium and aluminium pollution on the diversity of zooplankton: a case study in the Chimaliapan wetland (Ramsar site) (Lerma basin, Mexico).

    Science.gov (United States)

    García-García, Gerardo; Nandini, S; Sarma, S S S; Martínez-Jerónimo, Fernando; Jiménez-Contreras, Jorge

    2012-01-01

    Biological monitoring and the use of biotic indices are important in evaluating the health of aquatic systems. However, zooplankton are rarely included in biomonitoring protocols. We conducted a one-year study (March 2008-February 2009) at two sites from the Chimaliapan wetland, with concentrations of aluminium (Al) and chromium (Cr) above and within the permissible limits, respectively. Metals in the sediment and water were analyzed from three locations per site every two months. In addition to analyses of the abundance and diversity of rotifers, cladocerans and copepods, we sampled 11 physicochemical variables in the water and six from the sediments. The metal concentration in the polluted site (significantly above the permissible limits) ranged between 7266-8174 mg Kg(-1) of Al and 14.6-18.3 mg Kg(-1) of Cr. We found 92 species of rotifers, cladocerans and copepods. The Brillouin index for both sites ranged from 3.9-5.4, the Shannon-Wiener index from 4.2-5.5 while the Brachionus-Trichocerca ratio ranged between 1.0 and 1.7. The Wetland Zooplankton Index was significantly different among the sites; 2.63 at site 1 and 2.13 at site 2. The saprobic index was 3.2 for both sites. Data analyses using multifactorial techniques suggested that zooplankton can be used to evaluate the impact of the metals aforementioned, since these organisms are generally more sensitive than other groups and also have a high ecological relevance.

  2. Zooplankton standing and diversity in the Gulf of Kachchh with special reference to larvae of decapoda and pisces

    Digital Repository Service at National Institute of Oceanography (India)

    Paulinose, V.T.; Devi, C.B.L.; Nair, V.R.; Ramaiah, Neelam; Gajbhiye, S.N.

    Zooplankton characteristics of the Gulf of Kachchh including the major creek systems of Nakti, Kandla and Hansthal were studied for monsoon, postmonsoon and pre- monsoon periods. Zooplankton collections were made at 7 locations. The area was very...

  3. Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles

    DEFF Research Database (Denmark)

    Le Quéré, Corinne; Buitenhuis, Erik T.; Moriarty, Róisín

    2016-01-01

    zooplankton community, despite iron limitation of phytoplankton community growth rates. This result has implications for the representation of global biogeochemical cycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean....

  4. Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Gajbhiye, S.N; Krishnakumari, L; Desai, B.N

    Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra, India were studied at 9 stations during Feb. 1980 to Jan. 1981. The recorded variation in zooplankton biomass was 4.8-80.6 ml.(100 m super(3))/1 [av. 22.9 ml.(100 m...

  5. Biomass and composition of zooplankton in Auranga, Ambika, Purna and Mindola estuaries of south Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Gajbhiye, S.N.; JiyalalRam, M.J.; Desai, B.N.

    Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra, India were studied at 9 stations during Feb. 1980 to Jan. 1981. The recorded variation in zooplankton biomass was 4.8-80.6 ml.(100 m super(3))/1 [av. 22.9 ml.(100 m...

  6. Biomass and composition of zooplankton in and around Gulf of Kutch

    Digital Repository Service at National Institute of Oceanography (India)

    Govindan, K.; Kasinathan, R.; Desai, B.N.

    Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra, India were studied at 9 stations during Feb. 1980 to Jan. 1981. The recorded variation in zooplankton biomass was 4.8-80.6 ml.(100 m super(3))/1 [av. 22.9 ml.(100 m...

  7. Zooplankton standing stock, community structure and diversity in the northern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Srivastava, Y.

    The effects of large scale oil spill, which occurred during the Gulf War in 1991 on zooplankton standing stock, community structure and diversity in the northern Arabian Sea were studied. Surface (1-0 m) and vertical zooplankton hauls (200-0 m, 250...

  8. Distribution of toxic metals, Hg, Cd and Pb in zooplankton along the Indian coasts

    Digital Repository Service at National Institute of Oceanography (India)

    Sengupta, R.; Kureishy, T.W.

    Distribution of toxic metals such as Hg, Cd and Pb in zooplankton is assessed with a view to correlate it with the prevalent environmental conditions along the Indian coast. While Hg could not be detected in zooplankton the concentrations of Cd...

  9. Zooplankton standing stock and composition in coastal waters of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Temporal and spatial variability in standing stock and zooplankton composition at 5 stations along the Goa Coast, India during 1975-76 were studied. Standing stock values ranged from 22.81 to 53.65 mg C.m/3. Zooplankton community was diverse...

  10. Ecological patterns, diversity and core taxa of microbial communities in groundwater-fed rapid gravity filters

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    2016-01-01

    the second most and most abundant fraction in PFs (27±23%) and AFs (45.2±23%), respectively, and were far more abundant than typical proteobacterial ammonium-oxidizing bacteria, suggesting a physiology beyond nitrite oxidation for Nitrospira. Within the core taxa, sequences closely related to types...... with ability to oxidize ammonium, nitrite, iron, manganese and methane as primary growth substrate were identified and dominated in both PFs (73.6±6%) and AFs (61.4±21%), suggesting their functional importance. Surprisingly, operational taxonomic unit richness correlated strongly and positively with sampling...... location in the drinking water treatment plant (from PFs to AFs), and a weaker negative correlation held for evenness. Significant spatial heterogeneity in microbial community composition was detected in both PFs and AFs, and was higher in the AFs. This is the first comprehensive documentation of microbial...

  11. Zulma Ageitos de Castellanos: Publications and status of described taxa.

    Science.gov (United States)

    Signorelli, Javier H; Urteaga, Diego; Teso, Valeria

    2015-10-28

    Zulma Ageitos de Castellanos was an Argentinian malacologist working in the "Facultad de Ciencias Naturales y Museo" at La Plata University where she taught invertebrate zoology between 1947 and 1990. Her scientific publications are listed in chronological order. Described genus-group and species-group taxa are listed. Information about the type locality and type material, and taxonomic remarks are also provided. Finally, type material of all described taxa was requested and, when located, illustrated.

  12. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  13. Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy

    Directory of Open Access Journals (Sweden)

    Barbara Leoni

    2016-09-01

    Full Text Available Seasonal changes in trophic position and food sources of deep subalpine lake (Lake Iseo, Northern Italy zooplankton taxa were investigated during the year 2011. Furthermore, it's combined carbon and nitrogen Stable Isotope Analysis (SIA with size-specific analyses of both, the major predatory cladoceran (Leptodora kindtii, Focke and two potential preys (Daphnia longispina complex and Eubosmina longicornis. SIA studies have been extremely useful to track the energy flow through complex trophic network, however, if it is applied to analyze relation between two/few species may lead to misleading interpretations. In fact, integrating size-specificity allowed for understanding why L. kindtii nitrogen isotopic fingerprint fully overlapped with Daphnia, in spring. By investigating changes in L. kindtii's feeding basket, we found that in spring, L. kindtii mainly relied upon E. longicornis as prey, Daphnia being of too large body size for being captured by L. kindtii. Among preys encountered directly in front by a free-swimming Leptodora, only those able to fit into basket opening can be captured. As basket diameter increases with animal body length, size selection of prey depends on L. kindtii body length. As in other deep, subalpine lakes, E. longicornis was less 15N-enriched than Daphnia, most likely because of exploiting nitrogen fixing, cyanobacteria colonies, commonly detected in Lake Iseo with the onset of thermal stratification. Cyclopoid adults were at the top of zooplankton food chain and they could potentially be feeding on Daphnia. They, however, likely fed in a different habitat (>20 m deep water, as suggested by a rather than negligible carbon fractionation. The results overall suggest that size-specificity is crucial for addressing space and time changes in trophic links between organisms composing the two hierarchical levels within open water zooplankton community. 

  14. Potential acidification impacts on zooplankton in CCS leakage scenarios.

    Science.gov (United States)

    Halsband, Claudia; Kurihara, Haruko

    2013-08-30

    Carbon capture and storage (CCS) technologies involve localized acidification of significant volumes of seawater, inhabited mainly by planktonic species. Knowledge on potential impacts of these techniques on the survival and physiology of zooplankton, and subsequent consequences for ecosystem health in targeted areas, is scarce. The recent literature has a focus on anthropogenic greenhouse gas emissions into the atmosphere, leading to enhanced absorption of CO2 by the oceans and a lowered seawater pH, termed ocean acidification. These studies explore the effects of changes in seawater chemistry, as predicted by climate models for the end of this century, on marine biota. Early studies have used unrealistically severe CO2/pH values in this context, but are relevant for CCS leakage scenarios. Little studied meso- and bathypelagic species of the deep sea may be especially vulnerable, as well as vertically migrating zooplankton, which require significant residence times at great depths as part of their life cycle. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Effects of the ``Amoco Cadiz'' oil spill on zooplankton

    Science.gov (United States)

    Samain, J. F.; Moal, J.; Coum, A.; Le Coz, J. R.; Daniel, J. Y.

    1980-03-01

    A survey of zooplankton physiology on the northern coast of Brittany (France) was carried out over a one-year period by comparing two estuarine areas, one oil-polluted area (Aber Benoit) following the oil spill by the tanker “Amoco Cadiz” and one non-oil-polluted area (Rade de Brest). A new approach to an ecological survey was made by describing trophic relationships using analysis of digestive enzyme equipment (amylase and trypsin) of zooplankton organisms, mesoplankton populations and some selected species. These measurements allowed determination of (a) groups of populations with homogeneous trophic and faunistic characteristics and (b) groups of species with homogeneous trophic characteristics. The study of the appearance of these groups over a one-year period revealed the succession of populations and their adaptation to the environment on the basis of biochemical analysis. These phenomena observed in the compared areas showed marked differences in the most polluted areas during the productive spring period. Specific treatment of the data using unusual correlations between digestive enzymes is discussed in terms of the immediate effect on the whole population and on a copepod ( Anomalocera patersoni) living in the upper 10 cm.

  16. Transfer and accumulation of 106Ru from phytoplankton (Dunaliella bioculata) to zooplankton (Artemia salina)

    International Nuclear Information System (INIS)

    Izumo, Yoshiro; Takase, Akira

    1982-01-01

    106 Ru is one of the most abundant radionuclides to be released from the unclear-spent fuel reprocessing plant to oceans. This paper deals with transfer and accumulation of the radionuclide from phytoplankton (Dunaliella) to zooplankton (Artemia) in the graizing food chain of marine organisms. Each plankton was reared in the radioactive sea water A (filtrated and circulated through sandy mud, and the radioactive concentration decreased and atteined to constant after addition of 106 Ru), B (not filtrated and circulated, and the radioactive concentration decreased and atteined to constant) and C (not filtrated and circulated, the radioactive concentration decreased, but did not attein to constant), respectively, and investigated accumulations of 106 Ru. Then, accumulations of 106 Ru in Artemia by the ingestion of each diet (Dunaliella) contaminated with 106 Ru in each water, were investigated and compared with those from each water. Concentration factors of 106 Ru for the planktons reared in the radioactive sea waters were different among these waters. The difference can be attributable to that of physicochemical states of 106 Ru in the waters. It was found that 106 Ru would be accumulated by Artemia from the water A about 10 times higher than from the contaminated diet (Dunaliella) in this water, however from the contaminated diet (Dunaliella) in the water B about 2.2 times higher than from the last water. (author)

  17. Infestation of zooplankton with Triaenophorus and Proteocephalus procercoids (Cestoda in a deep oligotrophic lake

    Directory of Open Access Journals (Sweden)

    Peter Anegg

    2014-07-01

    Full Text Available In spring 2004, a massive infestation of the whitefish population in the Austrian Lake Achensee with Triaenophorus crassus was observed. Procercoids, the larval stage of parasitic cestodes, infest copepods as their first intermediate host. Therefore, in spring 2011, zooplankton samples were taken weekly at two sampling sites and depth ranges to determine the abundances of crustaceans as well as percentages of infected copepods and temporal occurrence of parasites. In addition, whitefish (Coregonus lavaretus stomach contents were analysed for food spectrum and parasite infestation. From the end of June to mid-August, procercoids of Triaenophorus spp. were detected in Cyclops abyssorum, the only first intermediate host for this parasite in Lake Achensee. Highest percentages of infected copepods were reached in mid-July (prevalence: 0.38%. Furthermore, an infestation of Proteocephalus sp. was observed in this copepod species, which occurred earlier until the end of the sampling period (prevalence: 1.34%. Besides C. abyssorum, also Eudiaptomus gracilis was occasionally infected with Proteocephalus (prevalence: 0.05%. The procercoids were found in both depth ranges, with no clear vertical infestation preference. More female C. abyssorum were Triaenophorus-infected than males, while the opposite was observed for Proteocephalus infection. The whitefish stomachs contained large numbers of Proteocephalus and Triaenophorus procercoids, coinciding with the occurrence of these parasites in the copepods.

  18. Multisensor sampling of pelagic ecosystem variables in a coastal environment to estimate zooplankton grazing impact

    Science.gov (United States)

    Sutton, Tracey; Hopkins, Thomas; Remsen, Andrew; Burghart, Scott

    2001-01-01

    Sampling was conducted on the west Florida continental shelf ecosystem modeling site to estimate zooplankton grazing impact on primary production. Samples were collected with the high-resolution sampler, a towed array bearing electronic and optical sensors operating in tandem with a paired net/bottle verification system. A close biological-physical coupling was observed, with three main plankton communities: 1. a high-density inshore community dominated by larvaceans coincident with a salinity gradient; 2. a low-density offshore community dominated by small calanoid copepods coincident with the warm mixed layer; and 3. a high-density offshore community dominated by small poecilostomatoid and cyclopoid copepods and ostracods coincident with cooler, sub-pycnocline oceanic water. Both high-density communities were associated with relatively turbid water. Applying available grazing rates from the literature to our abundance data, grazing pressure mirrored the above bio-physical pattern, with the offshore sub-pycnocline community contributing ˜65% of grazing pressure despite representing only 19% of the total volume of the transect. This suggests that grazing pressure is highly localized, emphasizing the importance of high-resolution sampling to better understand plankton dynamics. A comparison of our grazing rate estimates with primary production estimates suggests that mesozooplankton do not control the fate of phytoplankton over much of the area studied (<5% grazing of daily primary production), but "hot spots" (˜25-50% grazing) do occur which may have an effect on floral composition.

  19. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  20. Multiple marker abundance profiling

    DEFF Research Database (Denmark)

    Hooper, Cornelia M.; Stevens, Tim J.; Saukkonen, Anna

    2017-01-01

    proteins and the scoring accuracy of lower-abundance proteins in Arabidopsis. NPAS was combined with subcellular protein localization data, facilitating quantitative estimations of organelle abundance during routine experimental procedures. A suite of targeted proteomics markers for subcellular compartment...

  1. Two stressors and a community - Effects of hydrological disturbance and a toxicant on freshwater zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Stampfli, Nathalie C. [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau (Germany); Knillmann, Saskia [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Department of Ecosystem Analyses, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Liess, Matthias [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Noskov, Yury A. [Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze St. 11, 630091 Novosibirsk (Russian Federation); Schaefer, Ralf B. [Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau (Germany); Beketov, Mikhail A., E-mail: mikhail.beketov@ufz.de [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)

    2013-02-15

    Climate change models predict an increase in the frequency and intensity of extreme fluctuations in water level in aquatic habitats. Therefore, it is necessary to understand the combined effects of hydrological fluctuations and toxicants on aquatic biological communities. We investigated the individual and combined effects of the insecticide esfenvalerate and recurring fluctuations in water level on zooplankton communities in a system of 55 outdoor pond microcosms. The communities were exposed to esfenvalerate contamination as a single pulse (at 0.03, 0.3, or 3 {mu}g/L) and gradual removal of water and its subsequent replacement over three cycles and monitored until 84 days after contamination. The results showed that the sensitivities of the community and its constituent populations to the toxicant were increased by the hydrological stress. Specifically, for both the community structure and abundance of Daphnia spp. the lowest-observed-effect concentrations (LOEC) were 0.03 and 0.3 {mu}g/L for the series with fluctuating and constant water levels, respectively. Despite these differences in sensitivity, the interactive effects of the two stressors were found to be additive for both the community structure and the abundance of the most affected species. Presumably, it was not possible to detect synergism due to the strong individual effects of the water level fluctuations. Recovery times in the series exposed to the highest pesticide concentration were 64 and 55 days under fluctuating and constant water level regimes, respectively. Competition and water quality are suggested to be the major factors that underlie the observed effects of fluctuations in the water level. For the ecological risk assessment of toxicants, the present results suggest that (i) community sensitivity may vary substantially, depending on the environmental context, and (ii) this variability can be assessed experimentally to derive safety factors (coefficients used to avoid unexpected effects

  2. Effects of increased zooplankton biomass on phytoplankton and cyanotoxins: A tropical mesocosm study.

    Science.gov (United States)

    Dos Santos Severiano, Juliana; Dos Santos Almeida-Melo, Viviane Lúcia; Bittencourt-Oliveira, Maria do Carmo; Chia, Mathias Ahii; do Nascimento Moura, Ariadne

    2018-01-01

    Zooplankton are important biocontrol agents for algal blooms in temperate lakes, while their potential in tropical and subtropical environments is not well understood. The aim of the present study was to evaluate the influence of increased zooplankton biomass on phytoplankton community and cyanotoxins (microcystins and saxitoxin) content of a tropical reservoir (Ipojuca reservoir, Brazil) using in situ mesocosms. Mesocosms consisted of 50L transparent polyethylene bags suspended in the reservoir for twelve days. Phytoplankton populations were exposed to treatments having 1 (control), 2, 3 and 4 times the biomass of zooplankton found in the reservoir at the beginning of the experiment. Filamentous cyanobacteria such as Planktothrix agardhii and Cylindrospermopsis raciborskii were not negatively influenced by increasing zooplankton biomass. In contrast, the treatments with 3 and 4 times zooplankton biomass negatively affected the cyanobacteria Aphanocapsa sp., Chroococcus sp., Dolichospermum sp., Merismopedia tenuissima, Microcystis aeruginosa and Pseudanabaena sp.; the diatom Cyclotella meneghiniana; and the cryptophyte Cryptomonas sp. Total microcystin concentration both increased and decreased at different times depending on zooplankton treatment, while saxitoxin level was not significantly different between the treatments and control. The results of the present study suggest that zooplankton biomass can be manipulated to control the excessive proliferation of non-filamentous bloom forming cyanobacteria (e.g. M. aeruginosa) and their associated cyanotoxins. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Zooplankton responses to sandbar opening in a tropical eutrophic coastal lagoon

    Science.gov (United States)

    Santangelo, Jayme M.; de M. Rocha, Adriana; Bozelli, Reinaldo L.; Carneiro, Luciana S.; de A. Esteves, Francisco

    2007-02-01

    The effects of a disturbance by sandbar opening on the zooplankton community were evaluated through a long-term study in an eutrophic and oligohaline system, Imboassica Lagoon, Rio de Janeiro, Brazil. Zooplankton samples and limnological data were collected monthly from March 2000 to February 2003. Before the sandbar was opened in February 2001, the lagoon showed eutrophic conditions, with high mean nutrient concentrations and low salinity (total nitrogen - TN = 190.28 μM, chlorophyll a content - Chl. a = 104.60 μg/L and salinity = 0.87'). During this period, the zooplankton species present, such as the rotifers Brachionus calyciflorus and Brachionus havanaensis, were typical of freshwater to oligohaline and eutrophic environments. After the sandbar opening, the lagoon changed to a lower trophic status and increased salinity (TN = 55.11 μM, Chl. a = 27.56 μg/L and salinity = 19.64'). As a result, the zooplankton community came to consist largely of the rotifer Brachionus plicatilis, marine copepods and meroplanktonic larvae, mainly Gastropoda. Salinity was the main force structuring the zooplankton community after the sandbar opening. Two years after this episode, the prior zooplankton community had not reestablished itself, indicating a low resilience to this disturbance. The conditions developed prior to a sandbar opening can be crucial to the community responses in the face of this disturbance and for the capacity of the original zooplankton community to re-establish itself.

  4. Quantifying quagga mussel veliger abundance and distribution in Copper Basin Reservoir (California) using acoustic backscatter.

    Science.gov (United States)

    Anderson, Michael A; Taylor, William D

    2011-11-01

    Quagga mussels (Dreissena bugensis) have been linked to oligotrophication of lakes, alteration of aquatic food webs, and fouling of infrastructure associated with water supply and power generation, causing potentially billions of dollars in direct and indirect damages. Understanding their abundance and distribution is key in slowing their advance, assessing their potential impacts, and evaluating effectiveness of control strategies. Volume backscatter strength (Sv) measurements at 201- and 430-kHz were compared with quagga mussel veliger and zooplankton abundances determined from samples collected using a Wisconsin closing net from the Copper Basin Reservoir on the Colorado River Aqueduct. The plankton within the lower portion of the water column (>18 m depth) was strongly dominated by D-shaped quagga mussel veligers, comprising up to 95-99% of the community, and allowed direct empirical measurement of their mean backscattering cross-section. The upper 0-18 m of the water column contained a smaller relative proportion of veligers based upon net sampling. The difference in mean volume backscatter strength at these two frequencies was found to decrease with decreasing zooplankton abundance (r(2) = 0.94), allowing for correction of Sv due to the contribution of zooplankton and the determination of veliger abundance in the reservoir. Hydroacoustic measurements revealed veligers were often present at high abundances (up to 100-200 ind L(-1)) in a thin 1-2 m layer at the thermocline, with considerable patchiness in their distribution observed along a 700 m transect on the reservoir. Under suitable conditions, hydroacoustic measurements can rapidly provide detailed information on the abundance and distribution of quagga mussel veligers over large areas with high horizontal and vertical resolution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Metabarcoding Reveals Seasonal and Temperature-Dependent Succession of Zooplankton Communities in the Red Sea

    KAUST Repository

    Casas, Laura; Pearman, John K.; Irigoien, Xabier

    2017-01-01

    Very little is known about the composition and the annual cycle of zooplankton assemblages in the Red Sea, a confined water body characterized by a high biodiversity and endemism but at the same time one of the most understudied areas in the world in terms of marine biodiversity. This high diversity together with the lack of references for several of the groups poses a problem in obtaining basic information on zooplankton seasonal patterns. In the present work, we used high throughput sequencing to examine the temporal and spatial distribution of the zooplankton communities inhabiting the epipelagic zone in the central Red Sea. The analysis of zooplankton assemblages collected at two sites—coastal and offshore—twice a month at several depth strata by using MANTA, Bongo and WP2 nets provides baseline information of the seasonal patterns of the zooplankton community over 1 year. We show that the seasonal fluctuation of zooplankton communities living in the upper 100 m of the water column is driven mainly by the annual changes in seawater temperature. The 18S rRNA gene was used for metabarcoding of zooplankton assemblages revealing 630 metazoan OTUs (97% similarity) in five phyla, highlighting the richness of the Red Sea community. During colder months, communities were characterized by lower richness and higher biomass than communities found during the hot season. Throughout the year the zooplankton communities were dominated by the class Maxillopoda, mainly represented by copepods and class Hydrozoa. The rise in the water temperature favors the appearance of classes Malacostraca, Cephalopoda, Gastropoda, and Saggitoidea. The present study provides essential baseline information for future monitoring and improves our knowledge of the marine ecosystem in the Red Sea while reporting the main environmental variable structuring zooplankton assemblages in this region.

  6. Metabarcoding Reveals Seasonal and Temperature-Dependent Succession of Zooplankton Communities in the Red Sea

    KAUST Repository

    Casas, Laura

    2017-08-02

    Very little is known about the composition and the annual cycle of zooplankton assemblages in the Red Sea, a confined water body characterized by a high biodiversity and endemism but at the same time one of the most understudied areas in the world in terms of marine biodiversity. This high diversity together with the lack of references for several of the groups poses a problem in obtaining basic information on zooplankton seasonal patterns. In the present work, we used high throughput sequencing to examine the temporal and spatial distribution of the zooplankton communities inhabiting the epipelagic zone in the central Red Sea. The analysis of zooplankton assemblages collected at two sites—coastal and offshore—twice a month at several depth strata by using MANTA, Bongo and WP2 nets provides baseline information of the seasonal patterns of the zooplankton community over 1 year. We show that the seasonal fluctuation of zooplankton communities living in the upper 100 m of the water column is driven mainly by the annual changes in seawater temperature. The 18S rRNA gene was used for metabarcoding of zooplankton assemblages revealing 630 metazoan OTUs (97% similarity) in five phyla, highlighting the richness of the Red Sea community. During colder months, communities were characterized by lower richness and higher biomass than communities found during the hot season. Throughout the year the zooplankton communities were dominated by the class Maxillopoda, mainly represented by copepods and class Hydrozoa. The rise in the water temperature favors the appearance of classes Malacostraca, Cephalopoda, Gastropoda, and Saggitoidea. The present study provides essential baseline information for future monitoring and improves our knowledge of the marine ecosystem in the Red Sea while reporting the main environmental variable structuring zooplankton assemblages in this region.

  7. Metabarcoding Reveals Seasonal and Temperature-Dependent Succession of Zooplankton Communities in the Red Sea

    Directory of Open Access Journals (Sweden)

    Laura Casas

    2017-08-01

    Full Text Available Very little is known about the composition and the annual cycle of zooplankton assemblages in the Red Sea, a confined water body characterized by a high biodiversity and endemism but at the same time one of the most understudied areas in the world in terms of marine biodiversity. This high diversity together with the lack of references for several of the groups poses a problem in obtaining basic information on zooplankton seasonal patterns. In the present work, we used high throughput sequencing to examine the temporal and spatial distribution of the zooplankton communities inhabiting the epipelagic zone in the central Red Sea. The analysis of zooplankton assemblages collected at two sites—coastal and offshore—twice a month at several depth strata by using MANTA, Bongo and WP2 nets provides baseline information of the seasonal patterns of the zooplankton community over 1 year. We show that the seasonal fluctuation of zooplankton communities living in the upper 100 m of the water column is driven mainly by the annual changes in seawater temperature. The 18S rRNA gene was used for metabarcoding of zooplankton assemblages revealing 630 metazoan OTUs (97% similarity in five phyla, highlighting the richness of the Red Sea community. During colder months, communities were characterized by lower richness and higher biomass than communities found during the hot season. Throughout the year the zooplankton communities were dominated by the class Maxillopoda, mainly represented by copepods and class Hydrozoa. The rise in the water temperature favors the appearance of classes Malacostraca, Cephalopoda, Gastropoda, and Saggitoidea. The present study provides essential baseline information for future monitoring and improves our knowledge of the marine ecosystem in the Red Sea while reporting the main environmental variable structuring zooplankton assemblages in this region.

  8. Spatial structure of the zooplankton community in the coastal upwelling system off central-southern Chile in spring 2004 as assessed by automated image analysis

    Science.gov (United States)

    Manríquez, Karen; Escribano, Ruben; Riquelme-Bugueño, Ramiro

    2012-01-01

    Size spectra of the mesozooplankton community was studied under the influence of coastal upwelling during austral spring 2004 in the coastal upwelling zone off central-southern Chile. Size spectra were derived from the ZooImage analysis of digitalized zooplankton samples obtained from the upper 200 m during a survey carried out under active upwelling (November 2004). An upwelling filament extended up to 180 km offshore, and the upper boundary of the oxygen minimum zone (1 mL O 2 L -1) varied between 20 m (nearshore) and 300 m depth (oceanic). The community descriptors (slope of the size spectra, size class index, abundance of size classes) were derived from the size spectra. Stepwise multiple regression analysis found significant correlations between these descriptors and oceanographic variables (temperature, dissolved oxygen, chlorophyll-a, OMZ depth). These data suggest an upwelling-dependent zooplankton distribution characterized by aggregations in a mid-shelf zone, where the log-normalized size spectra become flatter due to an increased abundance of larger size classes (>3 mm). In contrast, the inshore and offshore zones were dominated by small (zone coincided with moderate levels of chlorophyll-a (ca. 1 μg L -1) and the OMZ depth near 200 m. These spatial patterns and slopes of the size spectra however, were subjected to a significant day vs. night effect mostly explained by the diel vertical migration of the euphausiid Euphausia mucronata. This migration can descend below 200 m during the daylight, causing the larger size classes to disappear from the size spectrum and resulting in a steeper slope. Time-dependent effects must, therefore, be considered when examining the spatial patterns of zooplankton in coastal upwelling zones.

  9. Incorporation of nitrogen from N2 fixation into amino acids of zooplankton

    DEFF Research Database (Denmark)

    Loick-Wilde, Natalie; Dutz, Jörg; Miltner, Anja

    2012-01-01

    quantified the direct incorporation of 15N tracer from N2-fixing N. spumigena (diazotroph nitrogen) and ammonium-utilizing R. salina into the amino acid nitrogen (AA-N) of zooplankton using complementary gas chromatography– combustion–isotope ratio mass spectrometry, gas chromatography–mass spectrometry...... consistently low in E. affinis when exposed to N. spumigena, suggesting that these animals were reluctant to feed on N. spumigena. Essential isoleucine received most of the diazotroph nitrogen in field zooplankton, while nonessential amino acids received most 15N tracer in E. affinis. N. spumigena was clearly...... an important amino acid nitrogen source for Baltic Sea zooplankton...

  10. Relation between 234Th scavenging and zooplankton biomass in Mediterranean surface waters

    International Nuclear Information System (INIS)

    Schmidt, S.; Reyss, J.L.; Buat-Menard, P.; Nival, P.; Baker, M.

    1992-01-01

    Dissolved and particulate 234 Th activities were determined and phyto-and zooplankton biomass were periodically measured 8 miles off Nice (Mediterranean Sea) during spring 1987. The results show a strong variability of 234 Th distribution on short time scales in northwestern Mediterranean surface waters. The good correlation observed the zooplankton biomass and the rate of 234 Th export to deep water in particulate form is agreement with the assumption that the residence time of particulate 234 Th in oceanic surface waters is controlled by zooplankton grazing. Moreover, our results indicate the importance of salps in particular as efficient removers of small suspended particles in surface waters

  11. ZOOPLANKTON FAUNA OF BİNGÖL FLOATING ISLANDS IN WINTER SEASON

    OpenAIRE

    Şen Özdemir, Nurgül; Caf, Fatma

    2015-01-01

    In this study was carried out winter season in 2011; zooplankton faunaof the Bingol Floating Islands. To­tally 18 zooplankton species were determinedas fol­lows; 14 Rotifera, 3 Cladocera and 1 Copepoda. It was determined thatthis zooplanktonic organisms consist­ed of 87.74 % Rotifera, 6.83 % Cladocera, and3.36 %  copepodit stages, 2.07 %  nauplii of copepoda. Rotif­era were thedominant group with regard to both spe­cies numbers, and individual numbers ofspecies. Cy­clops vicinus from Copepoda...

  12. Differences in root uptake of radiocaesium by 30 plant taxa

    Energy Technology Data Exchange (ETDEWEB)

    Broadley, M R; Willey, N J [University of the West of England, Bristol (United Kingdom). Faculty of Applied Sciences

    1998-12-31

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 {mu}g radiolabelled Cs g{sup -1} soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author).

  13. Differences in root uptake of radiocaesium by 30 plant taxa

    International Nuclear Information System (INIS)

    Broadley, M.R.; Willey, N.J.

    1997-01-01

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 μg radiolabelled Cs g -1 soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author)

  14. Differences in root uptake of radiocaesium by 30 plant taxa

    Energy Technology Data Exchange (ETDEWEB)

    Broadley, M.R.; Willey, N.J. [University of the West of England, Bristol (United Kingdom). Faculty of Applied Sciences

    1997-12-31

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 {mu}g radiolabelled Cs g{sup -1} soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author).

  15. A “Rosetta Stone” for metazoan zooplankton: DNA barcode analysis of species diversity of the Sargasso Sea (Northwest Atlantic Ocean)

    Science.gov (United States)

    Bucklin, Ann; Ortman, Brian D.; Jennings, Robert M.; Nigro, Lisa M.; Sweetman, Christopher J.; Copley, Nancy J.; Sutton, Tracey; Wiebe, Peter H.

    2010-12-01

    Species diversity of the metazoan holozooplankton assemblage of the Sargasso Sea, Northwest Atlantic Ocean, was examined through coordinated morphological taxonomic identification of species and DNA sequencing of a ˜650 base-pair region of mitochondrial cytochrome oxidase I (mtCOI) as a DNA barcode (i.e., short sequence for species recognition and discrimination). Zooplankton collections were made from the surface to 5,000 meters during April, 2006 on the R/V R.H. Brown. Samples were examined by a ship-board team of morphological taxonomists; DNA barcoding was carried out in both ship-board and land-based DNA sequencing laboratories. DNA barcodes were determined for a total of 297 individuals of 175 holozooplankton species in four phyla, including: Cnidaria (Hydromedusae, 4 species; Siphonophora, 47); Arthropoda (Amphipoda, 10; Copepoda, 34; Decapoda, 9; Euphausiacea, 10; Mysidacea, 1; Ostracoda, 27); and Mollusca (Cephalopoda, 8; Heteropoda, 6; Pteropoda, 15); and Chaetognatha (4). Thirty species of fish (Teleostei) were also barcoded. For all seven zooplankton groups for which sufficient data were available, Kimura-2-Parameter genetic distances were significantly lower between individuals of the same species (mean=0.0114; S.D. 0.0117) than between individuals of different species within the same group (mean=0.3166; S.D. 0.0378). This difference, known as the barcode gap, ensures that mtCOI sequences are reliable characters for species identification for the oceanic holozooplankton assemblage. In addition, DNA barcodes allow recognition of new or undescribed species, reveal cryptic species within known taxa, and inform phylogeographic and population genetic studies of geographic variation. The growing database of "gold standard" DNA barcodes serves as a Rosetta Stone for marine zooplankton, providing the key for decoding species diversity by linking species names, morphology, and DNA sequence variation. In light of the pivotal position of zooplankton in ocean

  16. Behavior is a major determinant of predation risk in zooplankton

    DEFF Research Database (Denmark)

    Almeda, Rodrigo; van Someren Gréve, Hans; Kiørboe, Thomas

    2017-01-01

    as prey for different predatory copepods. Copepods with “active” feeding behaviors (feeding-current and cruising feeders) showed significantly higher mortality from predation (~2–8 times) than similarly sized copepods with low motility feeding behavior (ambush feeders). Copepod males, which have a more...... active motile behavior than females (mate-seeking behavior), suffered a higher predation mortality than females in most of the experiments. However, the predation risk for mate-searching behavior in copepods varied depending on feeding behavior with ambush feeders consistently having the greatest......Zooplankton exhibit different small-scale motile behaviors related to feeding and mating activities. These different motile behaviors may result in different levels of predation risk, which may partially determine the structure of planktonic communities. Here, we experimentally determined predation...

  17. Elemental concentration of zooplankton and their particulate products

    International Nuclear Information System (INIS)

    Fowler, S.W.; Oregioni, B.

    1974-01-01

    Since zooplankton fecal pellets and molts are major vectors in the vertical transport of zinc in the sea, analyses have been made also for other trace metals in these particulate products. Euphausiids and pelagic shrimp were collected live off the Monaco coast by taking several short oblique tows with an Issacs-Kidd midwater trawl. Animals were placed in clean sea water, sorted according to species and immediately transported to the laboratory in plastic containers filled with filtered sea water taken at the collection site. Samples of microplankton, which serve as food for the macroplankton were also taken. Elemental concentrations in whole euphausiids and shrimp were measured. It was observed that molt analyses strongly support the contention that crustacean molts play an important role in the transport of metals and radionuclides in marine ecosystems. Molts can release metals to the water column or sediments upon decomposition or serve as a rich source of metals for organisms of other trophic levels which ingest them

  18. Identifying the plant-associated microbiome across aquatic and terrestrial environments: the effects of amplification method on taxa discovery

    Energy Technology Data Exchange (ETDEWEB)

    Jackrel, Sara L. [Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street Chicago IL 60637 USA; Owens, Sarah M. [Biosciences Division, Argonne National Laboratory, 9700 S. Cass Avenue Lemont IL 60439 USA; Gilbert, Jack A. [Biosciences Division, Argonne National Laboratory, 9700 S. Cass Avenue Lemont IL 60439 USA; The Microbiome Center, Department of Surgery, The University of Chicago, 5841 S Maryland Ave Chicago IL 60637 USA; Pfister, Catherine A. [Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street Chicago IL 60637 USA

    2017-01-25

    Plants in terrestrial and aquatic environments contain a diverse microbiome. Yet, the chloroplast and mitochondria organelles of the plant eukaryotic cell originate from free-living cyanobacteria and Rickettsiales. This represents a challenge for sequencing the plant microbiome with universal primers, as ~99% of 16S rRNA sequences may consist of chloroplast and mitochondrial sequences. Peptide nucleic acid clamps offer a potential solution by blocking amplification of host-associated sequences. We assessed the efficacy of chloroplast and mitochondria-blocking clamps against a range of microbial taxa from soil, freshwater and marine environments. While we found that the mitochondrial blocking clamps appear to be a robust method for assessing animal-associated microbiota, Proteobacterial 16S rRNA binds to the chloroplast-blocking clamp, resulting in a strong sequencing bias against this group. We attribute this bias to a conserved 14-bp sequence in the Proteobacteria that matches the 17-bp chloroplast-blocking clamp sequence. By scanning the Greengenes database, we provide a reference list of nearly 1500 taxa that contain this 14-bp sequence, including 48 families such as the Rhodobacteraceae, Phyllobacteriaceae, Rhizobiaceae, Kiloniellaceae and Caulobacteraceae. To determine where these taxa are found in nature, we mapped this taxa reference list against the Earth Microbiome Project database. These taxa are abundant in a variety of environments, particularly aquatic and semiaquatic freshwater and marine habitats. To facilitate informed decisions on effective use of organelle-blocking clamps, we provide a searchable database of microbial taxa in the Greengenes and Silva databases matching various n-mer oligonucleotides of each PNA sequence.

  19. Using real-time PCR and Bayesian analysis to distinguish susceptible tubificid taxa important in the transmission of Myxobolus cerebralis, the cause of salmonid whirling disease.

    Science.gov (United States)

    Fytilis, Nikolaos; Rizzo, Donna M; Lamb, Ryan D; Kerans, Billie L; Stevens, Lori

    2013-05-01

    Aquatic oligochaetes have long been appreciated for their value in assessing habitat quality because they are ubiquitous sediment-dwelling filter feeders. Many oligochaete taxa are also important in the transmission of fish diseases. Distinguishing resistant and susceptible taxa is important for managing fish disease, yet challenging in practice. Tubifex tubifex (Oligochaeta: Tubificidae) is the definitive host for the complex life-cycle parasite, Myxobolus cerebralis, the causative agent of salmonid whirling disease. We developed two hydrolysis probe-based qualitative real-time PCR (qPCR) multiplex assays that distinguish among tubificid taxa collected from the Madison River, Montana, USA. The first assay distinguishes T. tubifex from Rhyacodrilus spp.; while the second classifies T. tubifex identified by the first assay into two genetic lineages (I and III). Specificity and sensitivity were optimized for each assay; the two assays showed specificity of 94.3% and 98.6% for the target oligochaetes, respectively. DNA sequencing verified the results. The development of these assays allowed us to more fully describe tubificid community composition (the taxa and their abundance at a site) and estimate the relative abundances of host taxa. To relate tubificid relative abundance to fish disease risk, we determined M. cerebralis infection prevalence in samples identified as T. tubifex using similar molecular techniques. Given prior information (i.e., morphological identification of sexually mature worms), Bayesian analysis inferred that the first qPCR assay improved taxonomic identification. Bayesian inference of the relative abundance of T. tubifex, combined with infection assay results, identified sites with a high prevalence of infected T. tubifex. To our knowledge, this study represents both the first assessment of oligochaete community composition using a qPCR assay based on fluorescent probes and the first use of Bayesian analysis to fully characterize the dominant

  20. Effect of water irrigation volume on Capsicum frutescens growth and plankton abundance in aquaponics system

    Science.gov (United States)

    Andriani, Y.; Dhahiyat, Y.; Zahidah; Subhan, U.; Iskandar; Zidni, I.; Mawardiani, T.

    2018-03-01

    This study aimed to understand Capsicum frutescens growth and plankton abundance in aquaponics culture. A Completely Randomized Design (CRD) with six treatments in triplicates comprising of treatment A (positive control using organic liquid fertilizer), B (negative control without fertilizer), C (drip irrigation aquaponics with a water debit of 100 ml/day/plant), D (drip irrigation aquaponics with a water debit of 150 ml/day/plant), E (drip irrigation with a water debit of 200 ml/day/plant), and F (drip irrigation aquaponics with a water debit of 250 ml/day/plant) was applied. The water used in treatments C, D, E, and F contained comet fish feces as fertilizer. C. frutescens growth and plankton abundance were observed. Analysis was conducted using analysis of variance for plant productivity and descriptive analysis for plankton abundance and water quality. The results of this study showed that the highest plant growth was seen in plants receiving F treatment with 50 ml/day drip irrigation. However, no significant difference was found when compared to the positive control with organic artificial fertilizer. Eleven types of phytoplankton and six types of zooplankton were found, with Stanieria sp. as the most abundant phytoplankton and Brachionus sp. and Epistylis sp. as the most abundant zooplanktons.

  1. Biochemical studies on some zooplankton off the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Rao, T.S.S.; Matondkar, S.G.P.

    Proximate biochemical analyses on twelve zooplankton species showed that protein was the predominant biochemical component followed by lipid. Carbohydrate content was very low especially in species with high water content or calcareous shell...

  2. Elemental (C, H, N) composition of zooplankton from north Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Bhat, K.L.; Ansari, Z.A.; Parulekar, A.H.

    found to be much lower than the values presently used in routine conversion factors. Such factors are now essentially needed for accounting role of zooplankton in sediment trap collections in Arabian Sea region...

  3. Biomass and biochemical composition of zooplankton from northwest Bay of Bengal during January 1990

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Goswami, S.C.

    Biomass, proximate composition, organic carbon and calorie content of assorted zooplankton from the surface waters were studied. Day and night stations revealed significant difference in biomass (displacement volume, dry wt and organic carbon...

  4. A Biogeographic Assessment of the Stellwagen Bank National Marine Sanctuary - Kriged Predictive Map of Zooplankton Samples

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton communities have been well studied in the northeast Atlantic (Sherman et al., 1983) and on Georges Bank within the Gulf of Maine (Bigelow, 1927; Davis,...

  5. Cost of reproduction in selected species of zooplankton (rotifers and cladocerans)

    NARCIS (Netherlands)

    Sarma, S.S.S.; Nandini, S.; Gulati, R.D.

    2002-01-01

    Reproduction is an energetically costly biological process. Among the freshwater zooplankton, rotifers and cladocerans reproduce parthenogenetically and the cost of reproduction can be estimated using the life table data from demographic studies. Reduced probability of future survival or future

  6. Comparative account on zooplankton in polluted and unpolluted estuaries of Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, B.N.; Gajbhiye, S.N.; JiyalalRam, M.J.; Nair, V.R.

    An assessment of the zooplankton biomass and composition in Kolak Par, Damanganga and Auranga estuaries was made. Among these four rivers pollution is severe in the first two, moderate in Damanganga and good water quality prevailed in Auranga...

  7. Zooplankton studies in Visakhapatnam harbour and nearshore waters, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rathod, V.; Sarma, V.V.

    Distribution of zooplankton biomass in the waters studied showed remarkable variations. The faunal composition was very diverse and the number of species present was more especially during late pre- and post-monsoon seasons with conspicuous decrease...

  8. Biochemical composition and caloric potential of zooplankton from Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sreepada, R.A.; Rivonker, C.U.; Parulekar, A.H.

    Proximate composition and variations in protein, lipid, carbohydrate, ash and organic carbon in zooplankton from 42 stations in the Bay of Bengal are reported. Average percentages of moisture, protein, lipid, carbohydrate, ash and carbon were 85...

  9. Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

    Science.gov (United States)

    Messié, Monique; Chavez, Francisco P.

    2017-09-01

    A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

  10. A Biogeographic Assessment of the Stellwagen Bank National Marine Sanctuary - Kriged Probability Map of Zooplankton Samples

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton communities have been well studied in the northeast Atlantic (Sherman et al., 1983) and on Georges Bank within the Gulf of Maine (Bigelow, 1927; Davis,...

  11. Building essential biodiversity variables (EBVs) of species distribution and abundance at a global scale.

    Science.gov (United States)

    Kissling, W Daniel; Ahumada, Jorge A; Bowser, Anne; Fernandez, Miguel; Fernández, Néstor; García, Enrique Alonso; Guralnick, Robert P; Isaac, Nick J B; Kelling, Steve; Los, Wouter; McRae, Louise; Mihoub, Jean-Baptiste; Obst, Matthias; Santamaria, Monica; Skidmore, Andrew K; Williams, Kristen J; Agosti, Donat; Amariles, Daniel; Arvanitidis, Christos; Bastin, Lucy; De Leo, Francesca; Egloff, Willi; Elith, Jane; Hobern, Donald; Martin, David; Pereira, Henrique M; Pesole, Graziano; Peterseil, Johannes; Saarenmaa, Hannu; Schigel, Dmitry; Schmeller, Dirk S; Segata, Nicola; Turak, Eren; Uhlir, Paul F; Wee, Brian; Hardisty, Alex R

    2018-02-01

    Much biodiversity data is collected worldwide, but it remains challenging to assemble the scattered knowledge for assessing biodiversity status and trends. The concept of Essential Biodiversity Variables (EBVs) was introduced to structure biodiversity monitoring globally, and to harmonize and standardize biodiversity data from disparate sources to capture a minimum set of critical variables required to study, report and manage biodiversity change. Here, we assess the challenges of a 'Big Data' approach to building global EBV data products across taxa and spatiotemporal scales, focusing on species distribution and abundance. The majority of currently available data on species distributions derives from incidentally reported observations or from surveys where presence-only or presence-absence data are sampled repeatedly with standardized protocols. Most abundance data come from opportunistic population counts or from population time series using standardized protocols (e.g. repeated surveys of the same population from single or multiple sites). Enormous complexity exists in integrating these heterogeneous, multi-source data sets across space, time, taxa and different sampling methods. Integration of such data into global EBV data products requires correcting biases introduced by imperfect detection and varying sampling effort, dealing with different spatial resolution and extents, harmonizing measurement units from different data sources or sampling methods, applying statistical tools and models for spatial inter- or extrapolation, and quantifying sources of uncertainty and errors in data and models. To support the development of EBVs by the Group on Earth Observations Biodiversity Observation Network (GEO BON), we identify 11 key workflow steps that will operationalize the process of building EBV data products within and across research infrastructures worldwide. These workflow steps take multiple sequential activities into account, including identification and

  12. Mammal taxa constituting potential coevolved reservoirs of filoviruses

    DEFF Research Database (Denmark)

    Peterson, A.Townsend; Papes, Monica; Carroll, Darin S.

    2007-01-01

    -term coevolved reservoir of the filoviruses based on a coarse, regional classification of occurrences; here, we greatly refine the geographic data set for the mammalian taxa based on rich occurrence data sets and range interpolations from ecological niche models for each species involved. This improved detail...

  13. The effectiveness of surrogate taxa to conserve freshwater biodiversity

    Science.gov (United States)

    Stewart, David R.; Underwood, Zachary E.; Rahel, Frank J.; Walters, Annika W.

    2018-01-01

    Establishing protected areas has long been an effective conservation strategy, and is often based on more readily surveyed species. The potential of any freshwater taxa to be a surrogate of other aquatic groups has not been fully explored. We compiled occurrence data on 72 species of freshwater fish, amphibians, mussels, and aquatic reptiles for the Great Plains, Wyoming. We used hierarchical Bayesian multi-species mixture models and MaxEnt models to describe species distributions, and program Zonation to identify conservation priority areas for each aquatic group. The landscape-scale factors that best characterized aquatic species distributions differed among groups. There was low agreement and congruence among taxa-specific conservation priorities (<20%), meaning that no surrogate priority areas would include or protect the best habitats of other aquatic taxa. We found that common, wide-ranging aquatic species were included in taxa-specific priority areas, but rare freshwater species were not included. Thus, the development of conservation priorities based on a single freshwater aquatic group would not protect all species in the other aquatic groups.

  14. High congruence of isotope sewage signals in multiple marine taxa

    International Nuclear Information System (INIS)

    Connolly, Rod M.; Gorman, Daniel; Hindell, Jeremy S.; Kildea, Timothy N.; Schlacher, Thomas A.

    2013-01-01

    Highlights: • Sewage inputs are routinely mapped with stable isotopes ( 15 N) in organisms. • We tested whether choice of species influences spatial 15 N distributions. • Spatial gradients were consistent between algae, seagrasses, crabs, and fish. • A match of sewage-N signals in multiple marine taxa has not been reported before. • Spatially-coupled transfers in the food web produce the congruence of N imprints. -- Abstract: Assessments of sewage pollution routinely employ stable nitrogen isotope analysis (δ 15 N) in biota, but multiple taxa are rarely used. This single species focus leads to underreporting of whether derived spatial N patterns are consistent. Here we test the question of ‘reproducibility’, incorporating ‘taxonomic replication’ in the measurement of δ 15 N gradients in algae, seagrasses, crabs and fish with distance from a sewage outfall on the Adelaide coast (southern Australia). Isotopic sewage signals were equally strong in all taxa and declined at the same rate. This congruence amongst taxa has not been reported previously. It implies that sewage-N propagates to fish via a tight spatial coupling between production and consumption processes, resulting from limited animal movement that closely preserves the spatial pollution imprint. In situations such as this where consumers mirror pollution signals of primary producers, analyses of higher trophic levels will capture a broader ambit of ecological effects

  15. 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....

  16. Simulation Modeling of Zooplankton and Benthos in Reservoirs: Documentation and Development of Model Constructs.

    Science.gov (United States)

    1980-03-01

    additional food sources were available. 111. Porter (1973), who examined in situ the selective grazing of algae by a zooplankton community in Fuller Pond...large green algae increased. 112. Anabaena affinis and A. flos- aguae were rarely consumed by the zooplankton and were unaffected by increased grazing...grazing rates over the limited temperature range of 170 to 21*C. Nauwerck (1959), who conducted in situ experiments at Lake Erken, Sweden, with Daphnia

  17. FORMATION OF BACTERIAL AND ZOOPLANKTON COMPONENT OF NATURAL FOOD BASE UNDER EFFECT OF TRADITIONAL ORGANIC FERTILIZERS

    Directory of Open Access Journals (Sweden)

    S. Krazhan

    2013-12-01

    Full Text Available Purpose. Characterization of bacteria and zooplankton in rearing ponds using traditional fertilizers: cattle manure and bird droppings in modern conditions for fish farming. Methodology. Material collection and processing were carried out according to conventional hydrochemical and hydrobiological methods. Findings. We consider forming of bacteria and zooplankton component of natural food base of Irkliiv herbivorous fish nursery rearing ponds under the influenced of traditional organic fertilizers such as bird droppings (0,12 t/ha and cattle manure (2,0 t/ha. Each pond was planted by ongrowing Nyvka carp larvae (40,0 thousand ind./ha with silver carp (1,0 thousand ind./ha and grass carp larvae (1,0 thousand ind./ha. Qualitative and quantitative development of bacteria and zooplankton in fish-breeding ponds was investigated. The results show that in the development of the studied invertebrate groups of zooplankton in production ponds had no significant differences, except for rotifers, which group prevailed by the biomass to 3,6 times in the pond with the introduction of humus. Originality. The parameters of bacteria and zooplankton by the application of traditional organic fertilizers at present fish farming are studied. Practical value. These quantitative indicators of bacteria and zooplankton of fish-rearing ponds with water supply from Kremenchug reservoir, the application of cattle manure and bird droppings could be offered as an optimum data at present fish production stage.

  18. Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea.

    Science.gov (United States)

    Hung, Chin-Chang; Ko, Fung-Chi; Gong, Gwo-Ching; Chen, Kuo-Shu; Wu, Jian-Ming; Chiang, Hsin-Lun; Peng, Sen-Chueh; Santschi, Peter H

    2014-06-15

    The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500 ng m(-3) in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2-23 ng m(-3)) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. High frequency mesozooplankton monitoring: Can imaging systems and automated sample analysis help us describe and interpret changes in zooplankton community composition and size structure — An example from a coastal site

    Science.gov (United States)

    Romagnan, Jean Baptiste; Aldamman, Lama; Gasparini, Stéphane; Nival, Paul; Aubert, Anaïs; Jamet, Jean Louis; Stemmann, Lars

    2016-10-01

    The present work aims to show that high throughput imaging systems can be useful to estimate mesozooplankton community size and taxonomic descriptors that can be the base for consistent large scale monitoring of plankton communities. Such monitoring is required by the European Marine Strategy Framework Directive (MSFD) in order to ensure the Good Environmental Status (GES) of European coastal and offshore marine ecosystems. Time and cost-effective, automatic, techniques are of high interest in this context. An imaging-based protocol has been applied to a high frequency time series (every second day between April 2003 to April 2004 on average) of zooplankton obtained in a coastal site of the NW Mediterranean Sea, Villefranche Bay. One hundred eighty four mesozooplankton net collected samples were analysed with a Zooscan and an associated semi-automatic classification technique. The constitution of a learning set designed to maximize copepod identification with more than 10,000 objects enabled the automatic sorting of copepods with an accuracy of 91% (true positives) and a contamination of 14% (false positives). Twenty seven samples were then chosen from the total copepod time series for detailed visual sorting of copepods after automatic identification. This method enabled the description of the dynamics of two well-known copepod species, Centropages typicus and Temora stylifera, and 7 other taxonomically broader copepod groups, in terms of size, biovolume and abundance-size distributions (size spectra). Also, total copepod size spectra underwent significant changes during the sampling period. These changes could be partially related to changes in the copepod assemblage taxonomic composition and size distributions. This study shows that the use of high throughput imaging systems is of great interest to extract relevant coarse (i.e. total abundance, size structure) and detailed (i.e. selected species dynamics) descriptors of zooplankton dynamics. Innovative

  20. The effects of power plant passage on zooplankton mortalities: Eight years of study at the Donald C. Cook Nuclear Plant

    International Nuclear Information System (INIS)

    Evans, M.S.; Warren, G.J.; Page, D.I.

    1986-01-01

    Zooplankton mortalities resulting from passage through the Donald C. Cook Nuclear Plant (southeastern Lake Michigan) were studied over an 8-year (1975-1982) period. The power plant operated at a low ΔT ( 0 C) and discharge water temperatures did not exceed 35 0 C (except September 1978). While zooplankton mortalities were significantly greater in discharge than intake waters, differences were small, averaging <3%. There was no evidence of additional delayed effects on zooplankton mortality following plant passage. There was no relationship between zooplankton mortalities and temperature (ΔT, discharge water temperature). Mechanical stresses appeared to be the major cause of zooplankton mortality. The authors hypothesize that fish predation, rather than power plant operation, probably was the major source of zooplankton mortality in inshore waters during much of the year. (author)

  1. Effect of water chemistry on zooplanktonic and microbial communities across freshwater ecotones in different macrophyte-dominated shallow lakes

    Directory of Open Access Journals (Sweden)

    Tomasz Mieczan

    2015-12-01

    Full Text Available Complex interactions between zooplankton and microbial food webs are vital to the ecosystem ecology of shallow lakes. However, little is known about how horizontal changes in environmental conditions may influence microbial and metazoan communities in shallow lakes. The specific goals of the study were i to describe environmental variables responsible for the distribution of bacteria, flagellates, ciliates and crustaceans in an adjacent canal, ecotone and reservoir (littoral-pelagic zone in two different types of lakes (Ceratophyllum-dominated and Potamogeton-dominated lakes; ii to determine whether the contact zone waters differ in hydrochemical and biological terms from the waters of the canal and the open water zone; iii and to evaluate the influence of particular macro-habitats (canal, canal/reservoir, littoral and pelagic zone on the interactions between components of the planktonic food web. We studied four shallow, eutrophic lakes in Polesie Lubelskie (eastern Poland. The highest diversity and abundance of microorganisms and crustaceans were observed in the canal-reservoir contact zone, while the lowest values were noted in the pelagic zone. Hence, the contact zone in the investigated lakes could fulfil the function of an ecotone, distinguished by a significant increase in biodiversity, abundance, and species specificity of micro- and macroorganisms. Weak relations between food web components were found in the Ceratophyllum-dominated lakes, where environmental variables explained the bulk of the total variance in plankton abundance, whereas in the Potamogeton-dominated lakes, where environmental variables had a minor role in the total variance in plankton abundance, strong predator-prey relations were noted. Spatial structure of habitats proved to be another important factor for relationships between food web components, as our study indicated that habitat complexity can reduce negative correlations between food web components. Our study

  2. Diverse, rare microbial taxa responded to the Deepwater Horizon deep-sea hydrocarbon plume.

    Science.gov (United States)

    Kleindienst, Sara; Grim, Sharon; Sogin, Mitchell; Bracco, Annalisa; Crespo-Medina, Melitza; Joye, Samantha B

    2016-02-01

    The Deepwater Horizon (DWH) oil well blowout generated an enormous plume of dispersed hydrocarbons that substantially altered the Gulf of Mexico's deep-sea microbial community. A significant enrichment of distinct microbial populations was observed, yet, little is known about the abundance and richness of specific microbial ecotypes involved in gas, oil and dispersant biodegradation in the wake of oil spills. Here, we document a previously unrecognized diversity of closely related taxa affiliating with Cycloclasticus, Colwellia and Oceanospirillaceae and describe their spatio-temporal distribution in the Gulf's deepwater, in close proximity to the discharge site and at increasing distance from it, before, during and after the discharge. A highly sensitive, computational method (oligotyping) applied to a data set generated from 454-tag pyrosequencing of bacterial 16S ribosomal RNA gene V4-V6 regions, enabled the detection of population dynamics at the sub-operational taxonomic unit level (0.2% sequence similarity). The biogeochemical signature of the deep-sea samples was assessed via total cell counts, concentrations of short-chain alkanes (C1-C5), nutrients, (colored) dissolved organic and inorganic carbon, as well as methane oxidation rates. Statistical analysis elucidated environmental factors that shaped ecologically relevant dynamics of oligotypes, which likely represent distinct ecotypes. Major hydrocarbon degraders, adapted to the slow-diffusive natural hydrocarbon seepage in the Gulf of Mexico, appeared unable to cope with the conditions encountered during the DWH spill or were outcompeted. In contrast, diverse, rare taxa increased rapidly in abundance, underscoring the importance of specialized sub-populations and potential ecotypes during massive deep-sea oil discharges and perhaps other large-scale perturbations.

  3. Abundance and stratification of soil macroarthropods in a Caatinga Forest in Northeast Brazil

    Directory of Open Access Journals (Sweden)

    VFP Araújo

    Full Text Available In arid and semiarid environments, seasonality usually exerts a strong influence on the composition and dynamics of the soil community. The soil macroarthropods were studied in a Caatinga forest located in the Reserva Particular do Patrimônio Natural (RPPN Fazenda Almas, São José dos Cordeiros, Paraíba, Brazil. Samples were collected during the dry and rainy seasons following the method proposed by the Tropical Soil Biology and Fertility Program (TSBF, with minor modifications. At each station, 15 soil blocks (20 × 20 × 30 cm: 12 L were extracted and divided into three layers: A (0-10 cm, B (10-20 cm, and C (20-30 cm. In the rainy and dry seasons 1,306 ± 543(se and 458 ± 212 ind.m-2 macroarthropods were found, respectively, with 35 and 18 respective taxa recorded. The abundance of individuals and taxa were significantly higher in the rainy season. Isoptera (57.8% was the most abundant taxon, followed by Hymenoptera: Formicidae (17.2%, Coleoptera larvae (7.3%, and Araneae (3.5%. In the rainy season, abundance in layer A (576 ± 138 ind.m-2 was significantly higher than that of layer C (117 ± 64 ind.m-2, but was not different from layer B (613 ± 480 ind.m-2. There was also no difference between the layer B and C abundances. In the dry season, abundance in layer B (232 ± 120 ind.m-2 was not significantly different compared to layer A (182 ± 129 ind.m-2, but was significantly higher than abundance in layer C (44 ± 35 ind.m-2. During the rainy season, layer A (34 taxa was significantly richer in taxa than layers B (19 taxa and C (11 taxa. On the other hand, during the dry season the richness of layers A (12 taxa and B (12 taxa was equal, but significantly higher than that of layer C (6 taxa. Richness of taxa and abundance were positively correlated with soil organic matter and negatively correlated with soil temperature. The community of soil macroarthropods in the area of Caatinga studied has taxonomic and functional structures that are

  4. Abundance and stratification of soil macroarthropods in a Caatinga Forest in Northeast Brazil.

    Science.gov (United States)

    Araújo, V F P; Bandeira, A G; Vasconcellos, A

    2010-10-01

    In arid and semiarid environments, seasonality usually exerts a strong influence on the composition and dynamics of the soil community. The soil macroarthropods were studied in a Caatinga forest located in the Reserva Particular do Patrimônio Natural (RPPN) Fazenda Almas, São José dos Cordeiros, Paraíba, Brazil. Samples were collected during the dry and rainy seasons following the method proposed by the Tropical Soil Biology and Fertility Program (TSBF), with minor modifications. At each station, 15 soil blocks (20 × 20 × 30 cm: 12 L) were extracted and divided into three layers: A (0-10 cm), B (10-20 cm), and C (20-30 cm). In the rainy and dry seasons 1,306 ± 543(se) and 458 ± 212 ind.m-2 macroarthropods were found, respectively, with 35 and 18 respective taxa recorded. The abundance of individuals and taxa were significantly higher in the rainy season. Isoptera (57.8%) was the most abundant taxon, followed by Hymenoptera: Formicidae (17.2%), Coleoptera larvae (7.3%), and Araneae (3.5%). In the rainy season, abundance in layer A (576 ± 138 ind.m-2) was significantly higher than that of layer C (117 ± 64 ind.m-2), but was not different from layer B (613 ± 480 ind.m-2). There was also no difference between the layer B and C abundances. In the dry season, abundance in layer B (232 ± 120 ind.m-2) was not significantly different compared to layer A (182 ± 129 ind.m-2), but was significantly higher than abundance in layer C (44 ± 35 ind.m-2). During the rainy season, layer A (34 taxa) was significantly richer in taxa than layers B (19 taxa) and C (11 taxa). On the other hand, during the dry season the richness of layers A (12 taxa) and B (12 taxa) was equal, but significantly higher than that of layer C (6 taxa). Richness of taxa and abundance were positively correlated with soil organic matter and negatively correlated with soil temperature. The community of soil macroarthropods in the area of Caatinga studied has taxonomic and functional structures that

  5. Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance

    Science.gov (United States)

    Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H.; De La Torre, Pedro R.; Nornes, Stein M.; Singh, Hanumant; Sørensen, Asgeir J.; Daase, Malin; Johnsen, Geir

    2018-01-01

    Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms’ response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity. PMID:29326985

  6. Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance.

    Science.gov (United States)

    Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H; De La Torre, Pedro R; Nornes, Stein M; Singh, Hanumant; Sørensen, Asgeir J; Daase, Malin; Johnsen, Geir

    2018-01-01

    Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity.

  7. Mapas de taxas epidemiológicas: uma abordagem Bayesiana

    Directory of Open Access Journals (Sweden)

    Assunção Renato Martins

    1998-01-01

    Full Text Available Neste artigo, apresentamos métodos estatísticos desenvolvidos recentemente para a análise de mapas de taxas de morbidade quando as unidades geográficas possuem pequenas populações de risco. Eles adotam a abordagem Bayesiana e utilizam métodos computacionais intensivos para estimação do risco de cada área. O objetivo dos métodos é separar a variabilidade das taxas devida às diferenças entre as regiões do risco subjacente daquela devida à pura flutuação aleatória. As estimativas de risco possuem um erro quadrático médio total menor que as estimativas usuais. Aplicamos esses novos métodos para estimar o risco de mortalidade infantil nos municípios de Minas Gerais em 1994.

  8. Agaricus section Xanthodermatei: a phylogenetic reconstruction with commentary on taxa.

    Science.gov (United States)

    Kerrigan, Richard W; Callac, Philippe; Guinberteau, Jacques; Challen, Michael P; Parra, Luis A

    2005-01-01

    Agaricus section Xanthodermatei comprises a group of species allied to A. xanthodermus and generally characterized by basidiomata having phenolic odors, transiently yellowing discolorations in some parts of the basidiome, Schaeffer's reaction negative, and mild to substantial toxicity. The section has a global distribution, while most included species have distributions restricted to regions of single continents. Using specimens and cultures from Europe, North America, and Hawaii, we analyzed DNA sequences from the ITS1+2 region of the nuclear rDNA to identify and characterize phylogenetically distinct entities and to construct a hypothesis of relationships, both among members of the section and with representative taxa from other sections of the genus. 61 sequences from affiliated taxa, plus 20 from six (or seven) other sections of Agaricus, and one Micropsalliota sequence, were evaluated under distance, maximum parsimony and maximum likelihood methods. We recognized 21 discrete entities in Xanthodermatei, including 14 established species and 7 new ones, three of which are described elsewhere. Four species from California, New Mexico, and France deserve further study before they are described. Type studies of American taxa are particularly emphasized, and a lectotype is designated for A. californicus. Section Xanthodermatei formed a single clade in most analyses, indicating that the traditional sectional characters noted above are good unifying characters that appear to have arisen only once within Agaricus. Deep divisions within the sequence-derived structure of the section could be interpreted as subsections in Xanthodermatei; however, various considerations led us to refrain from proposing new supraspecific taxa. The nearest neighbors of section Xanthodermatei are putatively in section Duploannulati.

  9. Previdência e Taxa de Juros no Brasil

    Directory of Open Access Journals (Sweden)

    Brian Bolarinwa Ogundairo

    Full Text Available O presente trabalho relaciona a alta taxa de juros real brasileira com o elevado gasto em previdência sob um regime de repartição. Para tanto, utilizamos uma versão padrão do modelo de gerações sobrepostas, com um regime de previdência misto (isto é, parte capitalização e parte repartição. O modelo é calibrado para a economia brasileira no período 2000-2014. Considera-se um estado estacionário inicial de modo a reproduzir a taxa de juros real média nesse período, sob um regime totalmente do tipo repartição. Simula-se então uma mudança para replicar os gastos em previdência do Chile, um país com um sistema majoritariamente do tipo capitalização. Em nossa especificação preferida, o modelo prevê uma queda de 1 ponto percentual na taxa de juros real (ao ano de longo prazo. Isso corresponde a 18% do diferencial médio de juros entre Brasil e Chile no período 2000-2014.

  10. Leaf structural adaptations of two Limonium miller (Plumbaginales, Plumbaginaceae taxa

    Directory of Open Access Journals (Sweden)

    Zorić Lana N.

    2013-01-01

    Full Text Available Limonium gmelinii (Willd. O. Kuntze 1891 subsp. hungaricum (Klokov Soó is Pannonian endemic subspecies that inhabits continental halobiomes, while Limonium anfractum (Salmon Salmon 1924 is one of the indicators of halophyte vegetation of marine rocks and its distribution is restricted to the southern parts of Mediterranean Sea coast. In this work, micromorphological and anatomical characters of leaves of these two Limonium taxa were analyzed, in order to examine their adaptations to specific environmental conditions on saline habitats. The results showed that both taxa exhibited strong xeromorphic adaptations that reflected in flat cell walls of epidermal cells, thick cuticle, high palisade/spongy tissue ratio, high index of palisade cells, the presence of sclereid idioblasts in leaf mesophyll and mechanical tissue by phloem and xylem. Both taxa are crynohalophytes and have salt glands on adaxial and abaxial epidermis for excretion of surplus salt. Relatively high dimensions of mesophyll cells, absence of non-glandular hairs and unprotected stomata slightly increased above the level of epidermal cells, are also adaptations to increased salinity. [Projekat Ministarstva nauke Republike Srbije, br. 173002

  11. Metal stress in zooplankton diapause production: post-hatching response.

    Science.gov (United States)

    Aránguiz-Acuña, Adriana; Pérez-Portilla, Pablo

    2017-04-01

    Aquatic organisms commonly respond to harsh conditions by forming diapausing stages, which enable populations to survive adverse periods forming egg banks. Production of diapausing eggs is frequently observed in monogonont rotifers, previously changing from asexual to partial sexual reproduction (mixis). In despite that zooplankton are frequently used in ecotoxicological assessment because of their sensitivity to various toxicants and their important role in the ecosystems, toxicity evaluations often consider the directly exposed population produced by parthenogenetic reproduction, exclusively. We assessed experimentally effects of exposure to metals on mixis delay and fitness of hatchlings of the rotifer Brachionus plicatilis obtained from a brackish water lagoon with high metal content, especially copper. We show that sub-lethal concentrations of copper affected traits related to sexual reproduction and diapausing egg production in the rotifer. Copper addition did not delay the start of mixis, suggesting that rapid initiation of mixis is promoted in risky environments, according to the hypothesis of mixis as an escape strategy. Higher investment in mixis was obtained when individuals were exposed to metal. Addition of copper negatively affected the hatching success of diapausing eggs and performance of hatchlings. Nevertheless, these effects were greater for individuals formed in non-metal conditions, suggesting an adaptive advantage of populations from natural sediments exposed to copper. These results highlight the ecological and evolutionary consequences of the presence of metals in freshwater environments by modulating diapause adaptive efficacy and the selective process in egg banks.

  12. Characterization of intermittency in zooplankton behaviour in turbulence.

    Science.gov (United States)

    Michalec, François-Gaël; Schmitt, François G; Souissi, Sami; Holzner, Markus

    2015-10-01

    We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of zooplankton patches in energetic environments.

  13. Ecological characterization and molecular differentiation of Culex pipiens complex taxa and Culex torrentium in eastern Austria.

    Science.gov (United States)

    Zittra, Carina; Flechl, Eva; Kothmayer, Michael; Vitecek, Simon; Rossiter, Heidemarie; Zechmeister, Thomas; Fuehrer, Hans-Peter

    2016-04-11

    Culex pipiens complex taxa differ in behaviour, ecophysiology and epidemiologic importance. Despite their epidemiologic significance, information on genetic diversity, occurrence and seasonal and spatial distribution patterns of the Cx. pipiens complex is still insufficient. Assessment of seasonal and spatial distribution patterns of Culex pipiens forms and their congener Cx. torrentium is crucial for the understanding of their vector-pathogen dynamics. Female mosquitoes were trapped from April-October 2014 twice a month for a 24-h time period with BG-sentinel traps at 24 sampling sites in eastern Austria, using carbon dioxide as attractant. Ecological forms of Cx. pipiens s.l. and their hybrids were differentiated using the CQ11 locus, and Cx. pipiens forms and their congener Cx. torrentium using the ACE-2 gene. Differential exploitation of ecological niches by Cx. pipiens forms and Cx. torrentium was analysed using likelihood ratio tests. Possible effects of environmental parameters on these taxa were tested using PERMANOVA based on distance matrices and, if significant, were modelled in nMDS ordination space to estimate non-linear relationships. For this study, 1476 Culex spp. were sampled. Culex pipiens f. pipiens representing 87.33 % of the total catch was most abundant, followed by hybrids of both forms (5.62 %), Cx. torrentium (3.79 %) and Cx. pipiens f. molestus (3.25 %). Differences in proportional abundances were found between land cover classes. Ecological parameters affecting seasonal and spatial distribution of these taxa in eastern Austria are precipitation duration, air temperature, sunlight and the interaction term of precipitation amount and the Danube water level, which can be interpreted as a proxy for breeding habitat availability. The Cx. pipiens complex of eastern Austria comprises both ecologically different forms, the mainly ornithophilic form pipiens and the mainly mammalophilic and anthropophilic form molestus. Heterogeneous agricultural

  14. Numerical studies of the influence of food ingestion on phytoplankton and zooplankton biomasses

    Directory of Open Access Journals (Sweden)

    Lidia Dzierzbicka-G³owacka

    2002-03-01

    Full Text Available This paper presents the numerical simulations of the influence of food ingestion by a herbivorous copepod on phytoplankton and zooplankton biomasses (PZB in the sea. The numerical studies were carried out using the phytoplankton-zooplankton-nutrient-detritus PhyZooNuDe biological upper layer model. This takes account both of fully developed primary production and regeneration mechanisms and of daily migration of zooplankton. In this model the zooplankton is treated not as a 'biomass' but as organisms having definite patterns of growth, reproduction and mortality. Assuming also that {Zoop} is composed ofi cohorts of copepods with weights Wi and numbers Zi, then {Zoop} = WiZi. The PhyZooNuDe model consists of three coupled, partial second-order differential equations of the diffusion type for phytoplankton, zooplankton and nutrients, and one ordinary first-order differential equation for the benthic detritus pool, together with initial and boundary conditions. The calculations were made during 90 days (April, May and June for the study area P1 (Gdansk Deep in an area 0z<=20 m with a vertical space step of 0.1 m and a time step of 300 s. The simulation given here demonstrated the importance of food ingestion by zooplankton in that it can alter the nature of the interactions of plants and herbivores. The analysis of these numerical studies indicate that the maximal ingestion rate and the half-saturation constant for grazing strongly affect the magnitude of the spring bloom and the cyanobacterial bloom, and also the total zooplankton biomass.

  15. ABUNDANCE AND ISOTOPIC COMPOSITION OF PLANKTONIC MICROCRUSTACEANS IN A CENTRAL AMAZON FLOODPLAIN LAKE: IMPLICATIONS FOR THE TROPHIC DYNAMICS OF THE PLANKTON COMMUNITY

    Directory of Open Access Journals (Sweden)

    Pedro Caraballo

    2016-01-01

    Full Text Available During the hydrological year from December 2007 to November 2008, monthly samplings in the pelagic, littoral and macrophytes zones were conducted in the Lago Catalão, a floodplain lake receiving a mixture of water from Negro and Solimões Rivers, in front of Manaus city. Taxonomic composition and their relative abundance of the planktonic microcrustaceans community was studied. Natural abundances of carbon (C and nitrogen (N stable isotopes were measured to indicate energy sources. Cladocerans were the most abundant, with a relative abundance of 60%, followed by the calanoid and cyclopoid copepods with relative abundances of 29% and 11%, respectively. Diaphanosoma spp. was the dominant cladoceran group during all the sampling periods. Cladocerans were also represented by Moina spp., Ceriodaphnia spp. and Daphnia gessneri. Three genera of calanoid copepods were found: Notodiaptomus spp, Rhacodiaptomus spp., and Argyrodiaptomus spp. The genus Mesocyclops spp. was identified among the cyclopoid copepods. Zooplankton δ13C values indicated that the aquatic macrophyte zone was distinct, with a mean of -27.31‰, which was more enriched than zooplankton in the pelagic and littoral zones, where they had mean δ13C values of -33.11 and -34.66‰, respectively. Overall, analysis of stable isotopes showed that regardless of the pathways, the initial source of carbon for the zooplankton was phytoplankton, with a minimal participation of heterotrophic bacteria.

  16. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa fed Chlorella vulgaris and Scenedesmus acutus cultured on different media

    Directory of Open Access Journals (Sweden)

    Jesús Morales-Ventura

    2012-09-01

    , ranged from 0.1-0.25/d and were significantly higher on C. vulgaris cultured in liquid fertilizer as compared to the other diets. The growth rates of M. macrocopa ranged from 0.1 to 0.38/d, and were highest with diets of C. vulgaris cultured in Bold medium and S. acutus cultured in fertilizer. Thus, regardless of the culture medium used, the growth rates of the evaluated zooplankton species were higher with Chlorella than with Scenedesmus. The peak population density was highest (2 800ind/mL for A. fissa fed Chlorella that was cultured on liquid fertilizers, while B. rubens and M. macrocopa had peak abundances of 480 and 12ind/mL, respectively under similar conditions.

  17. OXYGEN ABUNDANCES IN CEPHEIDS

    International Nuclear Information System (INIS)

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.; Kovtyukh, V. V.

    2013-01-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  18. Zooplankton and associated data from CTD casts from 05 May 1997 to 04 March 1998 as part of the Columbia River Land-Margin Ecosystem Research (NODC Accession 0000384)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton densities, zooplankton species identities, chlorophyll, transmissivity, and temperature data were collected from the ROBERT GORDON SPROUL, WECOMA, and...

  19. Structural-functional organization of the littoral zooplankton communities of the Kremenchutskiy reservoir

    Directory of Open Access Journals (Sweden)

    Z. Burian

    2018-03-01

    Full Text Available Purpose. To find out the present state of the structural and functional organization of the littoral zooplankton communities of the upper Kremenchuk reservoir in the area of ​​the Kaniv Nature Reserve. Methodology. The material was collected in the summer time of 2016 at six stations of the littoral zone of the upper Kremenchug reservoir. The collection and analysis were carried out using generally accepted methods. The objects of the research were representatives of three main groups of zooplankton (rotifers, cladocerans, copepods, as well as ostracods and larvae of bivalve molluscs. Statistical data processing was done in MS Excel 2013. Findings. The results of the study represent the present state and organisation of littoral zooplankton. The species richness of the littoral zooplankton of the upper Kremenchug reservoir was presented by 48 species. There are 20 species of monogonont rotifers, 18 cladocerans species and copepods – 10. The representatives of the rotifer-cladoceran complex dominated in the taxonomic composition that can be explained by the preservation of the river regime and the rheophilic conditions in this part of the reservoir. The analysis showed that according to the ecological spectrum of zooplankton groups, the representatives of the pelagic group dominated – 47.92%. As for the feeding type, the largest share was represented by the non-predatory group – 64.58%. After analyzing of the quantitative indices (density and biomass of zooplankton, it was found that they were lower than average for overgrown biotopes (112580 ± 129914 ind./m³ і 1.83 ± 2.07 g/m³ and low for open water (26160 ± 19161 ind./m³ і 0,82 ± 0,86 g/m³. Originality. The present state of structural and functional organization of the littoral zooplankton communities of the upper Kremenchug reservoir has been revealed. Practical significance. The conducted studies give the information about the structural and functional organization of the

  20. Local and regional factors influencing zooplankton communities in ...

    African Journals Online (AJOL)

    2010-02-19

    Feb 19, 2010 ... important grazer of algae during periods of high zooplank- ton abundance. This is .... arctic tundra pond microcrustacean communities. Can. J. Fish. Aquat. Sci. ... Guides to the Identification of the Micro- invertebrates of the ...

  1. Eclipse effects on field crops and marine zooplankton: the 29 March 2006 total solar eclipse

    Directory of Open Access Journals (Sweden)

    G. Economou

    2008-08-01

    Full Text Available Some effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on plant life and productivity, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in photosynthetic rates, by more than a factor of 5 in some cases, was observed, and the minimum values of photosynthetic rates ranged between 3.13 and 10.13 μmol CO2 m−2 s−1. The drop in solar irradiance and the increase in mesophyll CO2-concentration during the eclipse did not induce stomatal closure thus not blocking CO2 uptake by plants. Light effects on the photochemical phase of photosynthesis may be responsible for the observed depression in photosynthetic rates. Field studies addressing the migratory responses of marine zooplankton (micro-zooplankton (ciliates, and meso-zooplankton due to the rapid changes in underwater light intensity were also performed. The light intensity attenuation was simulated with the use of accurate underwater radiative transfer modeling techniques. Ciliates, responded to the rapid decrease in light intensity during the eclipse adopting night-time behaviour. From the meso-zooplankton assemblage, various vertical migratory behaviours were adopted by different species.

  2. Eclipse effects on field crops and marine zooplankton: the 29 March 2006 total solar eclipse

    Science.gov (United States)

    Economou, G.; Christou, E. D.; Giannakourou, A.; Gerasopoulos, E.; Georgopoulos, D.; Kotoulas, V.; Lyra, D.; Tsakalis, N.; Tzortziou, M.; Vahamidis, P.; Papathanassiou, E.; Karamanos, A.

    2008-08-01

    Some effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on plant life and productivity, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in photosynthetic rates, by more than a factor of 5 in some cases, was observed, and the minimum values of photosynthetic rates ranged between 3.13 and 10.13 μmol CO2 m-2 s-1. The drop in solar irradiance and the increase in mesophyll CO2-concentration during the eclipse did not induce stomatal closure thus not blocking CO2 uptake by plants. Light effects on the photochemical phase of photosynthesis may be responsible for the observed depression in photosynthetic rates. Field studies addressing the migratory responses of marine zooplankton (micro-zooplankton (ciliates), and meso-zooplankton) due to the rapid changes in underwater light intensity were also performed. The light intensity attenuation was simulated with the use of accurate underwater radiative transfer modeling techniques. Ciliates, responded to the rapid decrease in light intensity during the eclipse adopting night-time behaviour. From the meso-zooplankton assemblage, various vertical migratory behaviours were adopted by different species.

  3. Dynamics of zooplankton community of Lake Tarasmozero in long-term anthropogenic pollution

    Directory of Open Access Journals (Sweden)

    Kuchko Yaroslav Alexandrovich

    2014-11-01

    Full Text Available In the article the results of zooplankton studies in Lake Tarasmozero (Lizhma river basin are presented. Wastes from the trout-breeding complex "Kedrozero" have been collected in this pond since 1992. The obtained data showed that from 1989 to 2012 a number of changes in zooplankton community take place and it is the evidence of the gradual increase in the trophic status of the reservoir. The average biomass of zooplankton increased from 500 to 1000 mg/m3. According to the trophic index (Myaemets, 1979, Tarasmozero is replaced into the category of mesotrophic water reservoirs (0.5 - 1.0. Saprobity index raised from 0.95 to 1.42. In the composition of the zooplankton there noted such species, as Polyarthra luminosa, Filinia longiseta, Trichocerca insignis, Daphnia longispina, Cyclops kolensis, which serve as indicators of increased trophic level in the conditions of moderate latitudes. After the trout farm started off, Bcrus/Brot indicator considerably decreased indicating to increasing role of rotifers in the formation of the total biomass of the zooplankton. Currently, the dominant species include D. longispina, Bosmina longirostris, Mesocyclops leuckarti, Asplanchna priodonta. In spite of the fact that the current changes are not catastrophic, it is reasonable to monitor regularly the initial links of the trophic chain of the reservoir ecosystem

  4. Chemical cocktails in aquatic systems: Pesticide effects on the response and recovery of >20 animal taxa

    International Nuclear Information System (INIS)

    Hua, Jessica; Relyea, Rick

    2014-01-01

    Natural systems are often exposed to individual insecticides or combinations of multiple insecticides. Using an additive and substitutive design, we examined how populations and communities containing >20 animal taxa are affected by four insecticides applied individually and as a mixture for 18 wks in aquatic mesocosms. The four insecticides had distinct lethal effects on the response and recovery of cladocerans, copepods, amphipods, isopods, and amphibians but not snails. The lethal effect on cladocerans and copepods induced trophic cascades that facilitated algal blooms and abiotic changes (higher pH and dissolved oxygen, but lower light transmission). Exposure to endosulfan resulted in a lag effect reducing cladocerans and spring-breeding amphibian abundance. The reduction in spring-breeding amphibian abundance led to cascading indirect effects on summer-breeding amphibians. Finally, the mixture treatment had lethal effects throughout the community that led to long-term effects on amphibian mass and unique indirect consequences on phytoplankton and abiotic variables. - Highlights: • Insecticides had unique direct and indirect effects on response and recovery. • Due to lag effects, endosulfan was more toxic than expected based on 4d tests. • Variation in oviposition phenology led to positive effects on amphibians. • Lethal direct effects of mixtures were pervasive and led to unique indirect effects. - Insecticides applied individually and in a mixture have complex direct and indirect consequences on aquatic system response and recovery

  5. Zooplankton data collected from SWIMMER/DIVER in Coastal Waters of Hawaii; 07 February 1995 to 15 March 1995 (NODC Accession 9800149)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Coastal Waters of Hawaii from SWIMMER / DIVER. Data were collected from 07 February 1995 to 15 March...

  6. Temporal and spatial distribution of microcrustacean zooplankton in relation to turbidity and other environmental factors in a large tropical lake (L. Tana, Ethiopia)

    NARCIS (Netherlands)

    Dejen, E.; Vijverberg, J.; Nagelkerke, L.A.J.; Sibbing, F.A.

    2004-01-01

    The spatial and seasonal distribution of microcrustacean zooplankton of Lake Tana (Ethiopia) was monthly studied for 2 years. Concurrently, various environmental parameters were measured and related to zooplankton distribution. Canonical Correspondence Analysis (CCA) was used to estimate the

  7. Zooplankton, chemical, and other data collected from THOMAS G. THOMPSON in Arabian Sea; 09 January 1995 to 07 April 1995 (NODC Accession 9800109)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, chemical, and other data were collected using zooplankton net casts in Arabian Sea from THOMAS G. THOMPSON. Data were collected from 09 January 1995 to...

  8. Zooplankton data collected from unidentified platforms in Coastal Waters of Washington / Oregon; 22 May 1979 to 06 August 1980 (NODC Accession 9800143)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net and bottle casts in Coastal Waters of Washington / Oregon from unidentified platforms from Canada. Data were...

  9. Community level patterns in diverse systems: A case study of litter fauna in a Mexican pine-oak forest using higher taxa surrogates and re-sampling methods

    Science.gov (United States)

    Moreno, Claudia E.; Guevara, Roger; Sánchez-Rojas, Gerardo; Téllez, Dianeis; Verdú, José R.

    2008-01-01

    Environmental assessment at the community level in highly diverse ecosystems is limited by taxonomic constraints and statistical methods requiring true replicates. Our objective was to show how diverse systems can be studied at the community level using higher taxa as biodiversity surrogates, and re-sampling methods to allow comparisons. To illustrate this we compared the abundance, richness, evenness and diversity of the litter fauna in a pine-oak forest in central Mexico among seasons, sites and collecting methods. We also assessed changes in the abundance of trophic guilds and evaluated the relationships between community parameters and litter attributes. With the direct search method we observed differences in the rate of taxa accumulation between sites. Bootstrap analysis showed that abundance varied significantly between seasons and sampling methods, but not between sites. In contrast, diversity and evenness were significantly higher at the managed than at the non-managed site. Tree regression models show that abundance varied mainly between seasons, whereas taxa richness was affected by litter attributes (composition and moisture content). The abundance of trophic guilds varied among methods and seasons, but overall we found that parasitoids, predators and detrivores decreased under management. Therefore, although our results suggest that management has positive effects on the richness and diversity of litter fauna, the analysis of trophic guilds revealed a contrasting story. Our results indicate that functional groups and re-sampling methods may be used as tools for describing community patterns in highly diverse systems. Also, the higher taxa surrogacy could be seen as a preliminary approach when it is not possible to identify the specimens at a low taxonomic level in a reasonable period of time and in a context of limited financial resources, but further studies are needed to test whether the results are specific to a system or whether they are general

  10. Teoria da estrutura a termo das taxas de juros

    OpenAIRE

    Cox,John C.; Ingersoll Jr.,Jonathan E.; Ross,Stephen A.

    2007-01-01

    Este estudo usa um modelo intertemporal de equilíbrio geral de precificação de ativos para estudar a estrutura a termo das taxas de juros. Nesse modelo, expectativas, aversão ao risco, alternativas de investimento e preferências quanto ao momento do consumo atuam na determinação dos preços. Muitos fatores tradicionalmente mencionados como influentes sobre a estrutura a termo são, assim, incluídos de uma maneira plenamente condizente com o comportamento maximizador e as expectativas racionais....

  11. Measuring Stratigraphic Congruence Across Trees, Higher Taxa, and Time.

    Science.gov (United States)

    O'Connor, Anne; Wills, Matthew A

    2016-09-01

    The congruence between the order of cladistic branching and the first appearance dates of fossil lineages can be quantified using a variety of indices. Good matching is a prerequisite for the accurate time calibration of trees, while the distribution of congruence indices across large samples of cladograms has underpinned claims about temporal and taxonomic patterns of completeness in the fossil record. The most widely used stratigraphic congruence indices are the stratigraphic consistency index (SCI), the modified Manhattan stratigraphic measure (MSM*), and the gap excess ratio (GER) (plus its derivatives; the topological GER and the modified GER). Many factors are believed to variously bias these indices, with several empirical and simulation studies addressing some subset of the putative interactions. This study combines both approaches to quantify the effects (on all five indices) of eight variables reasoned to constrain the distribution of possible values (the number of taxa, tree balance, tree resolution, range of first occurrence (FO) dates, center of gravity of FO dates, the variability of FO dates, percentage of extant taxa, and percentage of taxa with no fossil record). Our empirical data set comprised 647 published animal and plant cladograms spanning the entire Phanerozoic, and for these data we also modeled the effects of mean age of FOs (as a proxy for clade age), the taxonomic rank of the clade, and the higher taxonomic group to which it belonged. The center of gravity of FO dates had not been investigated hitherto, and this was found to correlate most strongly with some measures of stratigraphic congruence in our empirical study (top-heavy clades had better congruence). The modified GER was the index least susceptible to bias. We found significant differences across higher taxa for all indices; arthropods had lower congruence and tetrapods higher congruence. Stratigraphic congruence-however measured-also varied throughout the Phanerozoic, reflecting

  12. Biomass, organic carbon and calorific content of zooplankton from the Arabian Sea off Central West coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Nair, V.R.

    Organic carbon content and calorific values of zooplankton varied from 18.35 to 32.49% (av. 27.8%) and from 2.56 to 4.71 k cal. g-1 dry wt (av. 3.99) respectively. Areawise off Gujarat sustained higher standing stock of zooplankton (77.18 mg m-3...

  13. Inter- and intra-specific diurnal habitat selection of zooplankton during the spring bloom observed by Video Plankton Recorder

    DEFF Research Database (Denmark)

    Sainmont, Julie; Gislason, Astthor; Heuschele, Jan

    2014-01-01

    Recorder (VPR), a tool that allows mapping of vertical zooplankton distributions with a far greater spatial resolution than conventional zooplankton nets. The study took place over a full day–night cycle in Disko Bay, Greenland, during the peak of the phytoplankton spring bloom. The sampling revealed...

  14. Vertical oceanic transport of alpha-radioactive nuclides by zooplankton fecal pellets

    International Nuclear Information System (INIS)

    Higgo, J.J.W.; Cherry, R.D.; Heyraud, M.; Fowler, S.W.; Beasley, T.M.

    1980-01-01

    This paper gives the results of research to explain the role played by marine plankton metabolism in the vertical oceanic transport of the alpha-emitting nuclides. The common Mediterranean euphausiid, Meganyctiphanes norvegica, was selected as the typical zooplanktonic species that is the focus of this work. Measurements of 239 240 Pu, 238 U, 232 Th, and 210 Po are reported in whole euphausiids and in euphausiid fecal pellets and molts. The resulting data are inserted into a simple model that describes the flux of an element through a zooplanktonic animal. Concentrations of the nuclides concerned are high in fecal pellets, at levels which are typical of geological rather than biological material. It is suggested that zooplanktonic fecal pellets play a significant role in the vertical oceanic transport of plutonium, thorium, and polonium

  15. Metal and proton toxicity to lake zooplankton: A chemical speciation based modelling approach

    International Nuclear Information System (INIS)

    Stockdale, Anthony; Tipping, Edward; Lofts, Stephen; Fott, Jan; Garmo, Øyvind A.; Hruska, Jakub; Keller, Bill; Löfgren, Stefan; Maberly, Stephen C.; Majer, Vladimir; Nierzwicki-Bauer, Sandra A.; Persson, Gunnar; Schartau, Ann-Kristin; Thackeray, Stephen J.

    2014-01-01

    The WHAM-F TOX model quantifies the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (F TOX ), a linear combination of the products of organism-bound cation and a toxic potency coefficient for each cation. We describe the application of the model to predict an observable ecological field variable, species richness of pelagic lake crustacean zooplankton, studied with respect to either acidification or the impacts of metals from smelters. The fitted results give toxic potencies increasing in the order H + TOX to relate combined toxic effects of protons and metal cations towards lake crustacean zooplankton. • The fitted results give toxic potencies increasing in the order H + TOX model has been applied to field data for pelagic lake crustacean zooplankton. The fitted results give metal toxic potencies increasing in the order H + < Al < Cu < Zn < Ni

  16. Orion A helium abundance

    International Nuclear Information System (INIS)

    Tsivilev, A.P.; Ershov, A.A.; Smirnov, G.T.; Sorochenko, R.L.

    1986-01-01

    The 22.4-GHz (H,He)66-alpha and 36.5-GHz (H,He)56-alpha radio recombination lines have been observed at several Jaffe-Pankonin positions in the central part of the Orion A source. The measured relative abundance of ionized helium increases with distance, averaging 11.6 percent at peripheral points. The observed behavior is interpreted by a blister-type model nebula, which implies that Orion A has a true He abundance of 12 percent, is moving with a radial velocity of 5 km/sec, and is expanding. 18 references

  17. Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter.

    Science.gov (United States)

    Last, Kim S; Hobbs, Laura; Berge, Jørgen; Brierley, Andrew S; Cottier, Finlo

    2016-01-25

    In extreme high-latitude marine environments that are without solar illumination in winter, light-mediated patterns of biological migration have historically been considered non-existent [1]. However, diel vertical migration (DVM) of zooplankton has been shown to occur even during the darkest part of the polar night, when illumination levels are exceptionally low [2, 3]. This paradox is, as yet, unexplained. Here, we present evidence of an unexpected uniform behavior across the entire Arctic, in fjord, shelf, slope and open sea, where vertical migrations of zooplankton are driven by lunar illumination. A shift from solar-day (24-hr period) to lunar-day (24.8-hr period) vertical migration takes place in winter when the moon rises above the horizon. Further, mass sinking of zooplankton from the surface waters and accumulation at a depth of ∼50 m occurs every 29.5 days in winter, coincident with the periods of full moon. Moonlight may enable predation of zooplankton by carnivorous zooplankters, fish, and birds now known to feed during the polar night [4]. Although primary production is almost nil at this time, lunar vertical migration (LVM) may facilitate monthly pulses of carbon remineralization, as they occur continuously in illuminated mesopelagic systems [5], due to community respiration of carnivorous and detritivorous zooplankton. The extent of LVM during the winter suggests that the behavior is highly conserved and adaptive and therefore needs to be considered as "baseline" zooplankton activity in a changing Arctic ocean [6-9]. VIDEO ABSTRACT. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Grazing experiments and model simulations of the role of zooplankton in Phaeocystis food webs

    Science.gov (United States)

    Verity, P. G.

    2000-08-01

    A combined empirical and modelling study was conducted to further examine the potential importance of grazing by zooplankton in pelagic food webs in which Phaeocystis is a significant or dominant component. Laboratory experiments were designed to measure ingestion of Phaeocystis and other potential prey items which co-occur with Phaeocystis. Grazers included copepods and ciliates, and prey included Phaeocystis colonies and solitary cells, diatoms, ciliates, bacteria, and detritus. These data were expressed in the model currency of nitrogen units, and fit to hyperbolic tangent equations which included minimum prey thresholds. These equations and literature data were used to constrain a food web model whose purpose was to investigate trophic interactions rather than to mimic actual events. Nevertheless, the model output was similar to the general pattern and magnitude of development of Phaeocystis-diatom communities in some environments where they occur, e.g. north Norwegian waters. The model included three forms of nitrogen, three phytoplankton groups, bacteria, two zooplankton groups, and detritus, with detailed flows between compartments. An important component of the model was inclusion of variable prey preferences for zooplankton. The experiments and model simulations suggest several salient conclusions. Phaeocystis globosa colonies were eaten by a medium-sized copepod species, but ingestion appeared to be strongly dependent upon a proper size match between grazer and prey. If not, colonies were eaten little if at all. Phaeocystis solitary cells were ingested rapidly by ciliate microzooplankton, in agreement with prior literature observations. In contrast, detritus was eaten comparatively slowly by both ciliates and copepods. Both types of zooplankton exhibited apparent minimum prey thresholds below which grazing did not occur or was inconsequential. Model simulations implied that transitions between life cycle stages of Phaeocystis may potentially be important

  19. Bioenergetics modeling of the annual consumption of zooplankton by pelagic fish feeding in the Northeast Atlantic

    DEFF Research Database (Denmark)

    Bachiller, Eneko; Utne, Kjell Rong; Jansen, Teunis

    2018-01-01

    The present study uses bioenergetics modeling to estimate the annual consumption of the main zooplankton groups by some of the most commercially important planktivorous fish stocks in the Northeast Atlantic, namely Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesi......The present study uses bioenergetics modeling to estimate the annual consumption of the main zooplankton groups by some of the most commercially important planktivorous fish stocks in the Northeast Atlantic, namely Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting...

  20. Stellar Oxygen Abundances

    Science.gov (United States)

    King, Jeremy

    1994-04-01

    This dissertation addresses several issues concerning stellar oxygen abundances. The 7774 {\\AA} O I triplet equivalent widths of Abia & Rebolo [1989, AJ, 347, 186] for metal-poor dwarfs are found to be systematically too high. I also argue that current effective temperatures used in halo star abundance studies may be ~150 K too low. New color-Teff relations are derived for metal-poor stars. Using the revised Teff values and improved equivalent widths for the 7774A O I triplet, the mean [O/Fe] ratio for a handful of halo stars is found to be +0.52 with no dependence on Teff or [Fe/H]. Possible cosmological implications of the hotter Teff scale are discussed along with additional evidence supporting the need for a higher temperature scale for metal-poor stars. Our Teff scale leads to a Spite Li plateau value of N(Li)=2.28 +/- 0.09. A conservative minimal primordial value of N(Li)=2.35 is inferred. If errors in the observations and models are considered, consistency with standard models of Big Bang nucleosynthesis is still achieved with this larger Li abundance. The revised Teff scale raises the observed B/Be ratio of HD 140283 from 10 to 12, making its value more comfortably consistent with the production of the observed B and Be by ordinary spallation. Our Teff values are found to be in good agreement with values predicted from both the Victoria and Yale isochrone color-Teff relations. Thus, it appears likely that no changes in globular cluster ages would result. Next, we examine the location of the break in the [O/Fe] versus [Fe/H] plane in a quantitative fashion. Analysis of a relatively homogeneous data set does not favor any unique break point in the range -1.7 /= -3), in agreement with the new results for halo dwarfs. We find that the gap in the observed [O/H] distribution, noted by Wheeler et al. [1989, ARAA, 27, 279], persists despite the addition of more O data and may betray the occurrence of a hiatus in star formation between the end of halo formation and

  1. Effect of internal tides in the distribution and abundance of microzooplankton in Todos Santos Bay (Ensenada, B.C.)

    Science.gov (United States)

    Valencia, A.; Ibañez Tejero, L.; Ladah, L. B.; Sanchez Velasco, L.; Barton, E. D.

    2016-02-01

    Microzooplankton trophically connects phytoplankton and zooplanktonic adults. Their distribution and abundance can be directly related to the inherent physical processes in the marine environment. In coastal waters, the distribution and transport of zooplankton, including microzooplankton, can be influenced by high frequency effects such as internal tides. To date, most of the work on planktonic organisms and their interaction with the internal tide has been focused on a few species, such as barnacles, bryozoans and crabs. The aim of this study was to determine the effect of internal tide on the vertical distribution and abundance of microzooplankton, with an emphasis on copepod nauplii, during the evolution of the internal tide in a summer period of strong thermal stratification. Samples were obtained by vertical plankton net (150 micron mesh) hauls at three depth strata (surface, mid-water and bottom in 25 m depth), independently, with a sampling frequency of every hour. The internal tide was detected by rapid changes in temperature and currents observed with thermistor chains and a bottom-mounted upward looking ADCP. Preliminary results shows a strong mode-1 baroclinic tidal signal. The highest abundance of copepod nauplii and microzooplankton biomass occurred at depth, associated with a strong tidal current. The abundance of copepod nauplii and the abundance of microzooplankton biomass in the surface and intermediate strata showed strong vertical displacements between both strata. Data suggest the vertical distribution of microzooplankton can be dependent on the internal tide.

  2. Rapid evolution of tolerance to road salt in zooplankton.

    Science.gov (United States)

    Coldsnow, Kayla D; Mattes, Brian M; Hintz, William D; Relyea, Rick A

    2017-03-01

    Organisms around the globe are experiencing novel environments created by human activities. One such disturbance of growing concern is the salinization of freshwater habitats from the application of road deicing salts, which creates salinity levels not experienced within the recent evolutionary history of most freshwater organisms. Moreover, salinization can induce trophic cascades and alter the structure of freshwater communities, but knowledge is still scarce about the ability of freshwater organisms to adapt to elevated salinity. We examined if a common zooplankton of freshwater lakes (Daphnia pulex) could evolve a tolerance to the most commonly used road deicing salt (sodium chloride, NaCl). Using a mesocosm experiment, we exposed freshwater communities containing Daphnia to five levels of NaCl (15, 100, 200, 500, and 1000 mg Cl -  L -1 ). After 2.5 months, we collected Daphnia from each mesocosm and raised them in the lab for three generations under low salt conditions (15 mg Cl -  L -1 ). We then conducted a time-to-death experiment with varying concentrations of NaCl (30, 1300, 1500, 1700, 1900 mg Cl -  L -1 ) to test for evolved tolerance. All Daphnia populations exhibited high survival when subsequently exposed to the lowest salt concentration (30 mg Cl -  L -1 ). At the intermediate concentration (1300 mg Cl -  L -1 ), however, populations previously exposed to elevated concentrations (i.e.100-1000 mg Cl -  L -1 ) had higher survival than populations previously exposed to natural background levels (15 mg Cl -  L -1 ). All populations survived poorly when subsequently exposed to the highest concentrations (1500, 1700, and 1900 mg Cl -  L -1 ). Our results show that the evolution of tolerance to moderate levels of salt can occur within 2.5 months, or 5-10 generations, in Daphnia. Given the importance of Daphnia in freshwater food webs, such evolved tolerance might allow Daphnia to buffer food webs from the impacts of freshwater

  3. Seed Germination of selected Taxa from Kachchh Desert, India

    Directory of Open Access Journals (Sweden)

    Vinay Madhukar RAOLE

    2010-06-01

    Full Text Available The district of Kachchh contains many culturally important plants. However, their conservation status is little known due to direct and indirect human activities. This study was undertaken with the aim of contributing to the conservation of the native species of these semi-arid regions through germination trials under laboratory conditions. Mature fruits of ten selected species were collected randomly from the known habitats to obtain viable seeds. These seeds were pre-treated with growth regulators singly or in combination after acid scarification or without scarification. Seeds were found to be dormant due to presence of thick seed coat or due to low level of endogenous hormonal level. Most of these seeds required different storage period to mature. Only seeds of Capparis cartilaginea germinated without treatment while the other species required treatments. Addition of growth regulators has enhanced seed germination in few taxa singly and in some plant cases in combination.

  4. Geographical range and local abundance of tree species in China.

    Directory of Open Access Journals (Sweden)

    Haibao Ren

    Full Text Available Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1 whether locally abundant species tend to be geographically widespread; 2 whether species are more abundant towards their range-centers; and 3 how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20-25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km(2, and >90% of 651 species had ranges >10(5 km(2. There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species' abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges.

  5. Fossil preservation and the stratigraphic ranges of taxa

    Science.gov (United States)

    Foote, M.; Raup, D. M.

    1996-01-01

    The incompleteness of the fossil record hinders the inference of evolutionary rates and patterns. Here, we derive relationships among true taxonomic durations, preservation probability, and observed taxonomic ranges. We use these relationships to estimate original distributions of taxonomic durations, preservation probability, and completeness (proportion of taxa preserved), given only the observed ranges. No data on occurrences within the ranges of taxa are required. When preservation is random and the original distribution of durations is exponential, the inference of durations, preservability, and completeness is exact. However, reasonable approximations are possible given non-exponential duration distributions and temporal and taxonomic variation in preservability. Thus, the approaches we describe have great potential in studies of taphonomy, evolutionary rates and patterns, and genealogy. Analyses of Upper Cambrian-Lower Ordovician trilobite species, Paleozoic crinoid genera, Jurassic bivalve species, and Cenozoic mammal species yield the following results: (1) The preservation probability inferred from stratigraphic ranges alone agrees with that inferred from the analysis of stratigraphic gaps when data on the latter are available. (2) Whereas median durations based on simple tabulations of observed ranges are biased by stratigraphic resolution, our estimates of median duration, extinction rate, and completeness are not biased.(3) The shorter geologic ranges of mammalian species relative to those of bivalves cannot be attributed to a difference in preservation potential. However, we cannot rule out the contribution of taxonomic practice to this difference. (4) In the groups studied, completeness (proportion of species [trilobites, bivalves, mammals] or genera [crinoids] preserved) ranges from 60% to 90%. The higher estimates of completeness at smaller geographic scales support previous suggestions that the incompleteness of the fossil record reflects loss of

  6. Ammonia abundances in comets

    Science.gov (United States)

    Wyckoff, S.; Tegler, S.; Engel, L.

    The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

  7. Characterizing Specimens of Kudzu and Related Taxa with RAPD's

    Science.gov (United States)

    D.K. Jewett; C.J. Jiang; K.O. Britton; J.H. Sun; J. Tang

    2003-01-01

    Kudzu [Pueraria montana (Lour.) Merr. var. lobata (Willd.) Maesen and Almeidal is a perennial, semi-woody, climbing legume in the tribe Phaseoleae Benth., subtribe Glycininae Benth. (Maesen 1985, Maesen and Almeida 1988, Ward 1998). It is native to China, where an abundance of natural enemies (Pemberton 1988) and its cultivation...

  8. Compilation of solar abundance data

    International Nuclear Information System (INIS)

    Hauge, Oe.; Engvold, O.

    1977-01-01

    Interest in the previous compilations of solar abundance data by the same authors (ITA--31 and ITA--39) has led to this third, revised edition. Solar abundance data of 67 elements are tabulated and in addition upper limits for the abundances of 5 elements are listed. References are made to 167 papers. A recommended abundance value is given for each element. (JIW)

  9. Abundances in galaxies

    International Nuclear Information System (INIS)

    Pagel, B.E.J.

    1991-01-01

    Standard (or mildly inhomogeneous) Big Bang nucleosynthesis theory is well confirmed by abundance measurements of light elements up to 7 Li and the resulting upper limit to the number of neutrino families confirmed in accelerator experiments. Extreme inhomogeneous models with a closure density in form of baryons seem to be ruled out and there is no evidence for a cosmic 'floor' to 9 Be or heavier elements predicted in some versions of those models. Galaxies show a correlation between luminous mass and abundance of carbon and heavier elements, usually attributed to escape of hot gas from shallow potential wells. Uncertainties include the role of dark matter and biparametric behaviour of ellipticals. Spirals have radial gradients which may arise from a variety of causes. In our own Galaxy one can distinguish three stellar populations - disk, halo and bulge - characterised by differing metallicity distribution functions. Differential abundance effects are found among different elements in stars as a function of metallicity and presumably age, notably in the ratio of oxygen and α-particle elements to iron. These may eventually be exploitable to set a time scale for the formation of the halo, bulge and disk. (orig.)

  10. Disentangling the counteracting effects of water content and carbon mass on zooplankton growth

    DEFF Research Database (Denmark)

    Mcconville, Kristian; Atkinson, Angus; Fileman, Elaine S.

    2017-01-01

    Zooplankton vary widely in carbon percentage (carbon mass as a percentage of wet mass), but are often described as either gelatinous or non-gelatinous. Here we update datasets of carbon percentage and growth rate to investigate whether carbon percentage is a continuous trait, and whether its incl...

  11. Zooplankton resting egg banks in permanent and temporary tropical aquatic systems

    Directory of Open Access Journals (Sweden)

    Luciana Rabelo Araújo

    Full Text Available AIM: We evaluated zooplankton resting egg banks and active communities in five coastal lagoons and in five temporary pools, aiming to compare the active and the dormant communities in such environments. As they differ in hydroperiod, we expected that pools present richer resting egg banks in comparison to those found in lagoons. METHODS: Zooplankton community was sampled twice in 2006 (lagoons and in 2010 (pools and resting egg banks were sampled once in December 2007 (lagoons and in May 2010 (pools. Resting eggs were isolated from the sediment by applying the sugar flotation method. RESULTS: In opposition to our expectation, species richness in the resting egg banks of pools did not differ from those of lagoons. Additionally, no difference was found between the active and the dormant zooplankton communities in each water body for both temporary and permanent environments. However, similarity between active and dormant communities was greater in permanent environments than it was in temporary environments. CONCLUSIONS: It seems that the diapause strategy observed in certain tropical zooplankton populations cannot be predicted based on the awareness of the environment type (permanent or temporary, since hatching cues may be species-specific.

  12. Concentration and toxicity of some metals in zooplankton from nearshore waters of Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Nair, V.R.; Narvekar, P.V.; Desai, B.N.

    Zooplankton samples collected from 4 stations located in the nearshore waters of Bombay were analysed for Cu, Co, Mn, Ni and Cd. Concentrations of Co, Mn and Ni were more in copepods and gelatinous organisms than in mysids and decapods. High...

  13. A coupled oscillator model describes normal and strange zooplankton swimming behaviour

    NARCIS (Netherlands)

    Ringelberg, J.; Lingeman, R.

    2003-01-01

    "Normal" swimming in marine and freshwater zooplankton is often intermittent with active upward and more passive downward displacements. In the freshwater cladoceran Daphnia, the pattern is sometimes regular enough to demonstrate the presence of a rhythm. Abnormal swimming patterns were also

  14. Organic carbon content of zooplankton from the nearshore waters of Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Gajbhiye, S.N.; Sayed, F.Y.

    Organic carbon content of zooplankton in the Versova Creek and Thana Creek (polluted areas), off Versova and off Mahim, Bombay, India (relatively unpolluted areas) varied respectively from 21.4-30, 13.2-38.4, 21.6-30 and 25.8-39.6% dry weight...

  15. Patchy zooplankton grazing and high energy conversion efficiency: ecological implications of sandeel behavior and strategy

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Christensen, Asbjørn; Rindorf, Anna

    2013-01-01

    of prey. Here we studied zooplankton consumption and energy conversion efficiency of lesser sandeel (Ammodytes marinus) in the central North Sea, using stomach data, length and weight-at-age data, bioenergetics, and hydrodynamic modeling. The results suggested: (i) Lesser sandeel in the Dogger area depend...... sandeel densities and growth rates per area than larger habitats...

  16. Emergent Macrophytes Support Zooplankton in a Shallow Tropical Lake: A Basis for Wetland Conservation

    Science.gov (United States)

    Gebrehiwot, Mesfin; Kifle, Demeke; Triest, Ludwig

    2017-12-01

    Understanding the biodiversity value of littoral zones of lakes is a priority for aquatic biodiversity conservation. However, less emphasis has been given to the littoral part of tropical African lakes, with many of the previous researches focusing only on the open water side. The aim of the present study was, therefore, to investigate the impact of the littoral zone of a shallow freshwater tropical lake (Ziway, Ethiopia), dominated by two emergent macrophytes, on zooplankton community structure. We hypothesized that the wetland vegetation serves as a preferred microhabitat for zooplankton communities. A lake with substantial coverage of emergent macrophytes was monitored monthly from January to August, 2016. The monitoring included the measurements of physical, chemical, and biological parameters. Sampling sites were selected to represent areas of the macrophyte vegetation ( Typha latifolia and Phragmites australis) and the open water part of the lake. Sites with macrophyte vegetation were found to be the home of more dense and diverse zooplankton community. However, during the period of high vegetation loss, the density of crustacean zooplankton showed significant reduction within the patches of macrophytes. From biodiversity conservation perspective, it was concluded that the preservation of such small areas of macrophytes covering the littoral zone of lakes could be as important as protecting the whole lake. However, the rapid degradation of wetland vegetation by human activities is a real threat to the lake ecosystem. In the not-too-far future, it could displace and evict riparian vegetation and the biota it supports.

  17. Zooplankton in littoral waters of a tropical lake: a revisited biodiversity

    Directory of Open Access Journals (Sweden)

    PM. Maia-Barbosa

    Full Text Available The present study was carried out in Lake Dom Helvécio, in the state of Minas Gerais, with two main objectives: to demonstrate the contribution of the littoral zone, in order to better characterize zooplankton fauna; and to assess the distribution of zooplankton species in different habitats, i.e., the littoral zone with and without aquatic vegetation. The samples were collected in February and July 2006, throughout the littoral zone of the lake, in areas with and without aquatic vegetation. We identified a total of 188 species, of which 130 are new records for Lake Dom Helvécio. One hundred and eighty-four species were identified in the littoral zone with aquatic vegetation, and 117 in the zone with no vegetation. The higher zooplankton richness in areas of the littoral zone with aquatic vegetation can be related to the greater environmental heterogeneity. Compared to previous studies on the littoral zones of lakes along the middle River Doce, the present study expended greater sampling effort, and identified many more species. In relation to biological conservation, this study demonstrated the importance of the littoral zone for better characterization and conservation of the zooplankton fauna, especially when it is colonized by aquatic vegetation. Underestimating the richness of species may provide inaccurate data on the biota, as well as on the ecological conditions in an environment.

  18. Trace metal dynamics in zooplankton from the Bay of Bengal during summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; DineshKumar, P.K.; Nair, M.; Muraleedharan, K.R.

    Trace metal (Fe, Co, Ni, Cu, Zn, Cd, and Pb) concentrations in zooplankton from the mixed layer were investigated at 8 coastal and 20 offshore stations in the western Bay of Bengal during the summer monsoon of 2003. The ecotoxicological importance...

  19. Biochemical composition and calorific value of zooplankton from northern part of Central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nandakumar, K.; Bhat, K.L.; Wagh, A.B.

    Average biomass value of zooplankton obtained was 22.69 ml 100 m-3. Average percentages of lipid, carbohydrate, protein and carbon were 6.3, 6.0, 23.6 and 34.62 respectively. Calorific values ranged between 6217 and 24708 J.g-1 dry wt (8082...

  20. Zooplankton from the shelf watrs off the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Peter, G.

    Zooplankton in the shelf waters of India from Dabhol to Tuticorin was studied during the 17th cruise of R.V. Gaveshani in March 1977. Biomass values were relatively high in the central zone between Mangalore and Alleppey. In the region between...

  1. Zooplankton community structure in the Yellow Sea and East China Sea in autumn

    Directory of Open Access Journals (Sweden)

    Hongju Chen

    2015-12-01

    Full Text Available Abstract Study on zooplankton spatial distribution is essential for understanding food web dynamics in marine ecosystems and fishery management. Here we elucidated the composition and distribution of large mesozooplankton on the continental shelf of the Yellow Sea and East China Sea, and explored the zooplankton community structure in these water masses. Sixty vertical hauls (bottom or 200 m in deep water to surface using a ring net (diameter 0.8 m, 505-μm mesh were exploited in November 2007. The biogeographic patterns of zooplankton communities were investigated using multivariate analysis methods; copepod biodiversity was analyzed using univariate indices. Copepods and protozoans were dominate in the communities. Based on the species composition, we divided the study areas into six station groups. Significant differences in zooplankton assemblages were detected between the Yellow Sea and East China Sea. Species richness was higher in East China Sea groups than those in Yellow Sea, whereas taxonomic distinctness was higher in Yellow Sea than in East China Sea. There was a clear relationship between the species composition and water mass group.

  2. Validity of zooplankton biomass estimates and energy equivalent in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.; Parulekar, A.H.

    , as deduced from the data on biochemical composition and energy content, it is evident that zooplankton of the Indian Ocean contains on an average 2.7% organic carbon, rather than the widely quoted value of 6.5%. The biomass production in terms of organic...

  3. Trace metal concentrations in zooplankton from the eastern Arabian Sea and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; Balachandran, K.K.; Nair, M.; Joseph, T.; DineshKumar, P.K.; Achuthankutty, C.T.; Nair, K.K.C.; Pillai, N.G.K.

    Trace metal contents in zooplankton samples were estimated as a part of the Marine Research-Living Resource program at 24 stations in the Bay of Bengal (November, 2002) and 29 stations in the Arabian Sea (September-October, 2003) during the Cruises...

  4. Heavy metals and zooplankton with special reference to Minamata (Japan) mercury pollution - A case study

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Hirota, R.

    content was 0.01 to 0.25 mu g g/1 (dry). Among the various groups of zooplankton studied chaetognaths, bivalve, and crustaceans showed higher rate of bioaccumulation. The distribution of other heavy metals was not abnormal and the values were below...

  5. Zooplankton composition and diversity at different location along Kalpakkam coastal sites

    International Nuclear Information System (INIS)

    Das, Subhashree; Ponnusamy, K.; Verma, Amrata; Munilkumar, S.; Rajaram, S.; Lakra, W.S.; Pal, Asim K.; Sreedevi, K.R.

    2015-01-01

    Zooplanktons are the base of aquatic food web which constitutes the most vital biological component in an aquatic ecosystem. They form an important link in the food chain from primary to tertiary level leading to the production of fishery and are known to serve as a food for larger organisms such as bivalves, crustaceans and fish. The present study was aimed to assess the composition and diversity among the different species of zooplankton in Kalpakkam coastal sites within 30 kms around Madras Atomic Power Station. Samples were collected using plankton net (mesh size 63 μm, mouth area 20 inch dia) from stations which were fixed using the GPS coordinates. The results of the present studies showed maximum zoo planktonic diversity in station N15 i.e. 15 km away from MAPS (Madras Atomic Power Station), as compared to the other selected sampling stations. Regarding composition of zooplankton at different sites along the MAPS, it was found Copepods dominated among the zooplankton forming up to 60% of total species composition which indicate that copepod species are likely to be good indicators of water-mass influence and changes. (author)

  6. Mercury, cadmium and lead in different tissues of fishes and in zooplankton from the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Kureishy, T.W.; Sanzgiri, S.; George, M.D.; Braganca, A.

    Several fishes, representing different trophic levels, and some zooplankton samples were analysed for Hg, Cd and Pb There is a wide variation in the concentrations of these elements Hg is quite low in practically all the tissues Cd and Pb show...

  7. Zooplankton incidence in abnormally high sea surface temperature in the Eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Zooplankton in an abnormally high sea surface temperature (33.1 to 33.8 degrees C) and alternate bands of slick formation were studied in the Eastern Arabian Sea during 26 and 29 April 1981. The phenomenon which may be due to intense diurnal heating...

  8. Standing stock and biochemical composition of zooplankton in the northeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Achuthankutty, C.T.

    function as a reserve food in tropical zooplankton. Lipid, carbohydrate, ash, carbon and calorific content did not show much variation. Standing crop was estimated as 352.13 mgC.m super(2) for the upper 50m column of the coastal region, 716.82 mgC.M super(2...

  9. The role of zooplankton in the feeding ecology of fish fry from some ...

    African Journals Online (AJOL)

    cyclopoid cope pods were the dominant food item of fry < 20 mm S.L., with the ... seas estuarine systems where the diet of fry has been intensively studied (e.g. ..... consumers in oceanic waters but in estuaries benthic herbivores and detritivores ... rine systems is via the zooplankton food chain (Blaber 1979;. Wooldridge ...

  10. Biochemical composition of zooplankton of Bombay High (oil platform) area in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat; Wagh

    the major component (greater than 80%) of zooplankton throughout the year. Of the proximate principals, protein formed the major component. Overall mean values, calculated as percentages of dry weight were 16.65 protein, 4.33 carbohydrate, 2.51 lipid and 23.43...

  11. Mercury concentration variability in the zooplankton of the southern Baltic coastal zone

    Science.gov (United States)

    Bełdowska, Magdalena; Mudrak-Cegiołka, Stella

    2017-12-01

    Being a toxic element, mercury is introduced to the human organism through the consumption of fish and seafood, which in turn often feed on zooplankton. The bioaccumulation of Hg by zooplankton is an important factor influencing the magnitude of the mercury load introduced with food into the predator organism. Therefore the present article attempts to identify the processes and factors influencing Hg concentration in the zooplankton of the coastal zone, an area where marine organisms - an attractive food source for humans - thrive. This is particularly important in areas where climate changes influence the species composition and quantity of plankton. The studies were carried out on three test sites in the coastal zone of the southern Baltic Sea in the period from December 2011 to May 2013. The obtained results show that the shorting of the winter season is conducive to Hg increase in zooplankton and, consequently, in the trophic chain. High mercury concentrations were measured in genus Synchaeta and Keratella when Mesodinium rubrum were predominant in phytoplankton, while other sources of this metal in the plankton fauna were epilithon, epiphton and microbenthos. This is of particular importance when it comes to sheltered bays and estuaries with low water dynamics.

  12. Zooplankton standing stock and diversity along an oceanic track in the western Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.

    Zooplankton samples were collected from 13 stations situated in the oceanic realm between latitudes 8 degrees 49 minutes N and 19 degrees 48 minutes S in January-February, 1981. Standing stock varied between 1.6 and 10.4 ml/100 m@u3...

  13. Size-dependent responses of zooplankton to submerged macrophyte restoration in a subtropical shallow lake

    Science.gov (United States)

    Zeng, Lei; He, Feng; Zhang, Yi; Liu, Biyun; Dai, Zhigang; Zhou, Qiaohong; Wu, Zhenbin

    2018-03-01

    To explore the size-dependent responses of zooplankton to submerged macrophyte restoration, we collected macrophyte, zooplankton and water quality samples seasonally from a subtropical shallow lake from 2010 to 2012. Special attention was given to changes in rotifers and crustaceans (cladocerans and copepods). The rotifers were grouped into three size classes (400 μm) to explore their size-related responses to macrophyte restoration. The results showed that during the restoration, the annual mean biomass and macrophyte coverage increased significantly from 0 to 637 g/m2 and 0 to 27%, respectively. In response, the density and biomass of crustaceans and the crustacean-to-rotifer ratio increased significantly, while the rotifer density decreased significantly. Moreover, rotifers showed significant sizedependent responses to macrophyte restoration. Specially, rotifers sized zooplankton tended to boom, while that of small rotifers was inhibited during macrophyte restoration. Redundancy analysis (RDA) revealed positive correlations between macrophytes and crustaceans, rotifers and COD or Chl- a, but negative correlations between macrophytes and COD or Chl- a, and between crustaceans and Chl- a. Moreover, the results indicate that increased predation on phytoplankton by large-sized zooplankton might be an important mechanism for macrophyte restoration during development of aquatic ecosystems, and that this mechanism played a very important role in promoting the formation of a clear-water state in subtropical shallow lakes.

  14. Rapid sewage pollution assessment by means of the coverage of epilithic taxa in a coastal area in the SW Atlantic.

    Science.gov (United States)

    Becherucci, M E; Jaubet, M L; Saracho Bottero, M A; Llanos, E N; Elías, R; Garaffo, G V

    2018-07-01

    The sewage pollution impact over coastal environment represents one of the main reasons explaining the deterioration of marine coastal ecosystems around the globe. This paper aims to detect promptly a putative sewage pollution impact in a Southwestern Atlantic coastal area of Argentina as well as to identify a straightforward way for monitoring, based on the relative abundance coverage of the intertidal epilithic taxa. Four sampling sites were distributed at increased distances from the sewage outfall where the cover of individual epilithic species was visually estimated. The surrounded outfall area (i.e. outfall site) resulted polluted with high percentages of organic matter in sediment and Enterococcus concentration in seawater. The structure of the community showed a remarkable difference between the polluted site (outfall site) and the unpolluted sites. The polychaete Boccardia proboscidea dominated the outfall site with variable abundances of the green algae Ulva sp. during the period of study, decreasing the diversity of the community, while the mussel Brachidontes rodriguezii and variable abundances of several algae species dominated the unpolluted sites. The monitoring of the benthic community represents an effective, non-destructive, relative inexpensive and rapid method to assess the health of the coastal environment in the study area. The large abundance of B. proboscidea along with the absence of B. rodriguezii individuals at coastal ecosystem with certain gradient of pollution. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. The temporal dynamics of zooplankton communities of different types of water bodies within Ichniansky National Park

    Directory of Open Access Journals (Sweden)

    Z. V. Burian

    2017-05-01

    Full Text Available In recent decades, the influence of anthropogenic impact on aquatic ecosystems has increased. This has led to a restructuring of aquatic ecosystems and affected the structural and functional organization of groups of aquatic organisms, causing qualitative and quantitative changes. Particular attention is drawn to the different types of water bodies of protected areas like IchnyanskyNational Park, which is located in Ichnyansky district of Chernihiv region. This park is a newly created one, so the reduction in intensity of anthropogenic pressure can be traced within its waters. Zooplankton plays an important role in the functioning of trophic networks because it transfers energy from producers and primary consumers to young fish and planktonophagous fish. Therefore, three main groups of zooplankton were chosen as the object of study: rotifers (class Eurotatoria, cladocerans (class Branchiopoda, order Cladocera, different age stages of copepods (class Copepoda, and also ostracods (Class Ostracoda. The zooplankton used as research material was collected in the daytime in spring (April, summer (late July – early August and autumn (late September – early October in the years 2015–2016 from ten experimental stations. During this period 81 species of zooplankton were recorded within heterogeneous reservoirs of IchnianskyNational Park. Monogonont rotifers (subclass Monogononta included 35 species (43% of all species and bdelloid rotifers (subclass Bdelloidea, cladocerns, comprised 28 species (35%, and copepods included 18 species (22%. The faunal range of zooplankton over different years and seasons was characterized by the predominance of the rotator complex in spring, rotator-cladocerans and cladocerans in summer, and of the cladocerans complex in autumn. This was due to the formation during spring and summer of favourable conditions in the waters for filter feeders, which consist generally of rotifers and cladocerans. In autumn the water

  16. Feeding ecology of mesopelagic zooplankton of the subtropical and subarctic North Pacific Ocean determined with fatty acid biomarkers

    Science.gov (United States)

    Wilson, S. E.; Steinberg, D. K.; Chu, F.-L. E.; Bishop, J. K. B.

    2010-10-01

    Mesopelagic zooplankton may meet their nutritional and metabolic requirements in a number of ways including consumption of sinking particles, carnivory, and vertical migration. How these feeding modes change with depth or location, however, is poorly known. We analyzed fatty acid (FA) profiles to characterize zooplankton diet and large particle (>51 μm) composition in the mesopelagic zone (base of euphotic zone -1000 m) at two contrasting time-series sites in the subarctic (station K2) and subtropical (station ALOHA) Pacific Ocean. Total FA concentration was 15.5 times higher in zooplankton tissue at K2, largely due to FA storage by seasonal vertical migrators such as Neocalanus and Eucalanus. FA biomarkers specific to herbivory implied a higher plant-derived food source at mesotrophic K2 than at oligotrophic ALOHA. Zooplankton FA biomarkers specific to dinoflagellates and diatoms indicated that diatoms, and to a lesser extent, dinoflagellates were important food sources at K2. At ALOHA, dinoflagellate FAs were more prominent. Bacteria-specific FA biomarkers in zooplankton tissue were used as an indicator of particle feeding, and peaks were recorded at depths where known particle feeders were present at ALOHA (e.g., ostracods at 100-300 m). In contrast, depth profiles of bacterial FA were relatively constant with depth at K2. Diatom, dinoflagellate, and bacterial biomarkers were found in similar proportions in both zooplankton and particles with depth at both locations, providing additional evidence that mesopelagic zooplankton consume sinking particles. Carnivory indices were higher and increased significantly with depth at ALOHA, and exhibited distinct peaks at K2, representing an increase in dependence on other zooplankton for food in deep waters. Our results indicate that feeding ecology changes with depth as well as by location. These changes in zooplankton feeding ecology from the surface through the mesopelagic zone, and between contrasting environments

  17. Coincident Mass Occurrence of Gelatinous Zooplankton in Northern Norway

    Directory of Open Access Journals (Sweden)

    Tor Knutsen

    2018-05-01

    Full Text Available In autumn 2015, several sources reported observations of large amounts of gelatinous material in a large north Norwegian fjord system, either caught when trawling for other organisms or fouling fishing gear. The responsible organism was identified as a physonect siphonophore, Nanomia cara, while a ctenophore, Beroe cucumis, and a hydromedusa, Modeeria rotunda, were also registered in high abundances on a couple of occasions. To document the phenomena, we have compiled a variety of data from concurrent fisheries surveys and local fishermen, including physical samples, trawl catch, and acoustic data, photo and video evidence, and environmental data. Because of the gas-filled pneumatophore, characteristic for these types of siphonophores, acoustics provided detailed and unique insight to the horizontal and vertical distribution and potential abundances (~0.2–20 colonies·m−3 of N. cara with the highest concentrations observed in the near bottom region at ~320 m depth in the study area. This suggests that these animals were retained and accumulated in the deep basins of the fjord system possibly blooming here because of favorable environmental conditions and potentially higher prey availability compared to the shallower shelf areas to the north. Few cues as to the origin and onset of the bloom were found, but it may have originated from locally resident siphonophores. The characteristics of the deep-water masses in the fjord basins were different compared to the deep water outside the fjord system, suggesting no recent deep-water import to the fjords. However, water-masses containing siphonophores (not necessarily very abundant, may have been additionally introduced to the fjords at intermediate depths, with the animals subsequently trapped in the deeper fjord basins. The simultaneous observations of abundant siphonophores, hydromedusae, and ctenophores in the Lyngen-Kvænangen fjord system are intriguing, but difficult to provide a unified

  18. Supporting biodiversity by prescribed burning in grasslands - A multi-taxa approach.

    Science.gov (United States)

    Valkó, Orsolya; Deák, Balázs; Magura, Tibor; Török, Péter; Kelemen, András; Tóth, Katalin; Horváth, Roland; Nagy, Dávid D; Debnár, Zsuzsanna; Zsigrai, György; Kapocsi, István; Tóthmérész, Béla

    2016-12-01

    There are contrasting opinions on the use of prescribed burning management in European grasslands. On the one hand, prescribed burning can be effectively used for the management of open landscapes, controlling dominant species, reducing accumulated litter or decreasing wildfire risk. On the other hand burning can have a detrimental impact on grassland biodiversity by supporting competitor grasses and by threatening several rare and endangered species, especially arthropods. We studied the effects of prescribed burning in alkaline grasslands of high conservation interest. Our aim was to test whether dormant-season prescribed burning can be an alternative conservation measure in these grasslands. We selected six sites in East-Hungary: in three sites, a prescribed fire was applied in November 2011, while three sites remained unburnt. We studied the effects of burning on soil characteristics, plant biomass and on the composition of vegetation and arthropod assemblages (isopods, spiders, ground beetles and rove beetles). Soil pH, organic matter, potassium and phosphorous did not change, but soluble salt content increased significantly in the burnt sites. Prescribed burning had several positive effects from the nature conservation viewpoint. Shannon diversity and the number of flowering shoots were higher, and the cover of the dominant grass Festuca pseudovina was lower in the burnt sites. Graminoid biomass was lower, while total, green and forb biomass were higher in the burnt plots compared to the control. The key finding of our study was that prescribed burning did not decrease the abundance and diversity of arthropod taxa. Species-level analyses showed that out of the most abundant invertebrate species, 10 were not affected, 1 was negatively and 1 was positively affected by burning. Moreover, our results suggest that prescribed burning leaving unburnt patches can be a viable management tool in open landscapes, because it supports plant diversity and does not threaten

  19. Nonbreeding-Season Drivers of Population Dynamics in Seasonal Migrants: Conservation Parallels Across Taxa

    Directory of Open Access Journals (Sweden)

    Anna M. Calvert

    2009-12-01

    Full Text Available For seasonal migrants, logistical constraints have often limited conservation efforts to improving survival and reproduction during the breeding season only. Yet, mounting empirical evidence suggests that events occurring throughout the migratory life cycle can critically alter the demography of many migrant species. Herein, we build upon recent syntheses of avian migration research to review the role of non-breeding seasons in determining the population dynamics and fitness of diverse migratory taxa, including salmonid fishes, marine mammals, ungulates, sea turtles, butterflies, and numerous bird groups. We discuss several similarities across these varied migrants: (i non-breeding survivorship tends to be a strong driver of population growth; (ii non-breeding events can affect fitness in subsequent seasons through seasonal interactions at individual- and population-levels; (iii broad-scale climatic influences often alter non-breeding resources and migration timing, and may amplify population impacts through covariation among seasonal vital rates; and (iv changes to both stationary and migratory non-breeding habitats can have important consequences for abundance and population trends. Finally, we draw on these patterns to recommend that future conservation research for seasonal migrants will benefit from: (1 more explicit recognition of the important parallels among taxonomically diverse migratory animals; (2 an expanded research perspective focused on quantification of all seasonal vital rates and their interactions; and (3 the development of detailed population projection models that account for complexity and uncertainty in migrant population dynamics.

  20. Abundance, distribution, diversity and zoogeography of epipelagic copepods off the Egyptian Coast (Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Howaida Y. Zakaria

    2016-12-01

    Full Text Available The abundance, distribution and diversity of epipelagic copepods were studied along the Egyptian Mediterranean Coast during April, August, 2008, February, 2009 and 2010. The geographical distribution and ecological affinities of the recorded species are presented in order to follow up the migrant species that recently entered in the study area. Copepoda was the most dominant zooplankton group, representing 74.14% of the total zooplankton counts. The annual averages of copepod abundance in the coastal, shelf and offshore zones were 699.3, 609.7 and 555.7 ind.m−3, respectively. Spring was the most productive and diversified season. 118 copepod species were identified in the study area; among them twelve species are recorded in the Mediterranean Sea for the first time and 41 species are new records in the Egyptian Mediterranean waters. The community was dominated by Oithona nana, Calocalanus pavo, Nannocalanus minor, Clausocalanus arcuicornis and Paracalanus parvus. The study area could be considered as a crossroad for migration process from Atlantic Ocean in the west and Indian Ocean via Red Sea and Suez Canal from the south. In addition, the maritime activities in the Mediterranean Sea may have contributed into the change of copepod diversity in the study area where some species could have come to the Egyptian Coast from other water systems via ballast water.

  1. Anomalous behavior of tellurium abundances

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B L

    1984-01-01

    The cosmic abundance of Te is larger than for any element with atomic number greater than 40, but it is one of the least abundant elements in the earth's lithosphere and it is one of the five elements never reported in sea water. On the other hand, it is the fourth most abundant element in the human body (after Fe, Zn and Rb), and is unusually abundant in human food. It is shown that the high abundance in human food combined with the low abundance in soil requires that it be picked up by plant roots very much more efficiently than any other trace element.

  2. Primary controls on species richness in higher taxa.

    Science.gov (United States)

    Rabosky, Daniel L

    2010-12-01

    The disparity in species richness across the tree of life is one of the most striking and pervasive features of biological diversity. Some groups are exceptionally diverse, whereas many other groups are species poor. Differences in diversity among groups are frequently assumed to result from primary control by differential rates of net diversification. However, a major alternative explanation is that ecological and other factors exert primary control on clade diversity, such that apparent variation in net diversification rates is a secondary consequence of ecological limits on clade growth. Here, I consider a likelihood framework for distinguishing between these competing hypotheses. I incorporate hierarchical modeling to explicitly relax assumptions about the constancy of diversification rates across clades, and I propose several statistics for a posteriori evaluation of model adequacy. I apply the framework to a recent dated phylogeny of ants. My results reject the hypothesis that net diversification rates exert primary control on species richness in this group and demonstrate that clade diversity is better explained by total time-integrated speciation. These results further suggest that it may not possible to estimate meaningful speciation and extinction rates from higher-level phylogenies of extant taxa only.

  3. Concentrations of 137Cs and trace elements in zooplankton, and their vertical distributions off Rokkasho, Japan

    International Nuclear Information System (INIS)

    Kaeriyama, Hideki; Ishii, Toshiaki; Watabe, Teruhisa; Kusakabe, Masashi

    2007-01-01

    Zooplankton samples were collected at about 50 m depth with a large ring net (160-cm mouth diameter, 0.5-mm mesh) in May, June, October 2005 and June 2006 off Rokkasho, Japan where a nuclear fuel reprocessing plant will be in full-scale operation in the near future. Plankters in each sample were separated based on their species. Eight samples were used for the determination of 137 Cs concentration and the other 21 samples were used for the determination of its stable isotope, Cs along with some other trace elements. All the samples were characterized by five dominant species, i.e. euphausiids, chaetognaths, copepods; Neocalanus spp., amphipods; Themisto spp. and Cyphocaris sp. Plankton samples were also taken at three to five discrete depths between the surface and ≤ 1,000 m in depth during daytime and nighttime for analysis of vertical distribution patterns of biomass, and for assessment of daily vertical migration activity. Integrated net zooplankton biomass at nighttime ranged from 0.85 to 8.74 g-DW m -2 in the 0-150 m layer without any appreciable day-night differences in the vertical distribution; below the layer, it decreased significantly. Only in spring, appreciable day-night differences in the vertical distribution were observed at the shallowest station. Concentrations of Cs and Co did not show significant difference among the five species. However, higher concentrations of Sr were observed in two amphipods. It is likely that amphipods had a different biological process in Sr metabolism from others. The concentration of 137 Cs in zooplankton was usually very low and sometimes under the detection limit. In the present study, the highest concentration of 137 Cs in zooplankton was 24 mBq kg-WW -1 , corresponding to the concentration factor (CF) of 14, if the value of 1.7 mBq L -1 was given to the 137 Cs concentration in seawater. The water-column inventory of 137 Cs in a zooplankton community is calculated to be 0.29 to 1.95 mBq m -2 , based on the data on

  4. Restoring lakes by using artificial plant beds: habitat selection of zooplankton in a clear and a turbid shallow lake

    DEFF Research Database (Denmark)

    Schou, Majbritt Overgård; Risholt, Casper; Lauridsen, Torben L.

    2009-01-01

    1. Return of large-bodied zooplankton populations is of key importance for creating a shift from a turbid to a clear-water state in shallow lakes after a nutrient loading reduction. In temperate lakes, recovery is promoted by submerged macrophytes which function as a daytime refuge for large...... zooplankton. However, recovery of macrophytes is often delayed and use of artificial plant beds (APB) has been suggested as a tool to enhance zooplankton refuges, thereby reinforcing the shift to a clear-water state and, eventually, colonisation of natural plants. 2. To further evaluate the potential of APB...... in lake restoration, we followed the day–night habitat choices of zooplankton throughout summer in a clear and a turbid lake. Observations were made in the pelagic and littoral zones and in APB in the littoral representing three different plant densities (coverage 0%, 40% and 80%). 3. In the clear lake...

  5. Blooms of phytoplankton along the west coast of India associated with nutrient enrichment and the response of zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Devassy, V.P.; Madhupratap, M.

    and dinoflagellates are also common Spectacular bloom formations of Trichodesmium is a regular phenomenon during the later part of the NE monsoon season At times, these blooms cover hundreds of kilometres Very often successions of phyto- and zooplankton communities...

  6. Abundance, Excess, Waste

    Directory of Open Access Journals (Sweden)

    Rox De Luca

    2016-02-01

    Her recent work focuses on the concepts of abundance, excess and waste. These concerns translate directly into vibrant and colourful garlands that she constructs from discarded plastics collected on Bondi Beach where she lives. The process of collecting is fastidious, as is the process of sorting and grading the plastics by colour and size. This initial gathering and sorting process is followed by threading the components onto strings of wire. When completed, these assemblages stand in stark contrast to the ease of disposability associated with the materials that arrive on the shoreline as evidence of our collective human neglect and destruction of the environment around us. The contrast is heightened by the fact that the constructed garlands embody the paradoxical beauty of our plastic waste byproducts, while also evoking the ways by which those byproducts similarly accumulate in randomly assorted patterns across the oceans and beaches of the planet.

  7. Effects of physical forcing on COastal ZOoplankton community structure: study of the unusual case of a MEDiterranean ecosystem under strong tidal influence (Project COZOMED-MERMEX)

    Science.gov (United States)

    Pagano, Marc

    2017-04-01

    Groupe COZOMED: R. Arfi (1), A. Atoui (2), H. Ayadi (6), B. Bejaoui (1), N. Bhairy (1), N. Barraj (2), M. Belhassen (2), S. Benismail (2), M.Y Benkacem (2), J. Blanchot (1), M. Cankovic(5), F. Carlotti (1), C. Chevalier (1), I Ciglenecki-Jusic (5), D. Couet (1), N. Daly Yahia (3), L. Dammak (2), J.-L. Devenon (1), Z. Drira (6), A. Hamza (2), S. Kmia (6), N. Makhlouf (3), M. Mahfoudi (2), M. Moncef (4), M. Pagano (1), C. Sammari (2), H. Smeti (2), A. Zouari (2) The COZOMED-MERMEX project aims at understanding how hydrodynamic forcing (currents, tides, winds) combine with anthropogenic forcing and climate to affect the variability of coastal Mediterranean zooplankton communities under contrasting tidal influence. This study includes (i) a zero state of knowledge via a literature review of existing data and (ii) a case study on the system Boughrara lagoon - Gulf of Gabes. This ecosystem gives major services for Tunisia (about 65% of national fish production) but is weakened by its situation in a heavily anthropized area and under influence of urban, industrial and agricultural inputs. Besides this region is subject to specific climate forcing (Sahelian winds, scorching heat, intense evaporation, flooding) which possible changes will be considered. The expected issues are (i) to improve our knowledge of hydrodynamic forcing on zooplankton and ultimately on the functioning of coastal Mediterranean ecosystems impacted by anthropogenic and climatic effects and (ii) to elaborate management tools to help preserving good ecological status of these ecosystems: hydrodynamic circulation model, mapping of isochrones of residence times, mapping of the areas of highest zooplankton abundances (swarms), and sensitive areas, etc. This project strengthens existing scientific collaborations within the MERMEX program (The MerMex Group, 2011) and in the frame of an international joint laboratory (COSYS-Med) created in 2014. A first field mulidisciplinary campaign was performed in October

  8. Effects of acidification and cadmium pollution on the populations and habitats of limnetic zooplankton; Effekter av forsuring og kadmium-forurensning paa populasjoner og samfunn av limnisk zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Schartau, A K.L. [Norsk Inst. for Naturforskning, Trondheim (Norway)

    1996-01-01

    The conference paper deals with executed field tests on the adding of cadmium alone or combined with acidification of an enclosed space under different nutrient and predatory conditions. The addition of cadmium changed the biomass and the composition of the phytoplankton. In combination with the added nutrient salts, the biomass of special algae increased in the Cd loaded spaces, and the addition of acid changed the effect of Cd concentration by increased production of the same. The effect of a given Cd concentration on the zooplankton varied in a wide range of environmental conditions. 22 refs., 1 tab.

  9. Abundance of anemone fishes in North Bay Island and mass culture of live food organisms for their larval rearing

    Directory of Open Access Journals (Sweden)

    Rajaram Rajendran

    2014-12-01

    Full Text Available Understanding the transect survey for abundance of anemone fishes and other living organisms is important to asses reef associated fish diversity in North Bay island. The percentage distribution of 10 different substratum from the disturbed, semi-disturbed and undisturbed areas was recorded during the survey in North Bay islands during November 2009 to April 2010. The survey observations reveal that the fishes were the dominant groups followed by mollusks, lobsters and octopus. There are 5 different anemone fishes were collected during the transect survey and their distribution is more in undisturbed area. We are standardizing the different mass culture techniques for production of phytoplankton and zooplankton for the nutritional source for the anemone fish larvae. Monitoring the water quality parameters and culture the phytoplankton and zooplankton used in different culture media with 2 adjustment studies like with and without salinity adjustment. The results of this experiment indicate that zooplankton was rich in protein and fat content and it will be used as high nutritional source for feeding fish larvae.

  10. Emergent and floating-leaved macrophytes as refuge for zooplankton in a eutrophic temperate lake without submerged vegetation

    DEFF Research Database (Denmark)

    Cazzanelli, Matteo; Perlt, Trine Warming; Christoffersen, Kirsten Seestern

    2008-01-01

    Several studies have shown that submerged macrophytes provide a refuge for zooplankton against fish predation, whereas the role of emergent and floating-leaved species, which are often dominant in eutrophic turbid lakes, is far less investigated. Zooplankton density in open water and amongst....... As a consequence, especially in turbid lakes, the ecological role of these functional types of vegetation, and not merely that of submerged macrophyte species, should be taken into consideration....

  11. Normalization and microbial differential abundance strategies depend upon data characteristics.

    Science.gov (United States)

    Weiss, Sophie; Xu, Zhenjiang Zech; Peddada, Shyamal; Amir, Amnon; Bittinger, Kyle; Gonzalez, Antonio; Lozupone, Catherine; Zaneveld, Jesse R; Vázquez-Baeza, Yoshiki; Birmingham, Amanda; Hyde, Embriette R; Knight, Rob

    2017-03-03

    Data from 16S ribosomal RNA (rRNA) amplicon sequencing present challenges to ecological and statistical interpretation. In particular, library sizes often vary over several ranges of magnitude, and the data contains many zeros. Although we are typically interested in comparing relative abundance of taxa in the ecosystem of two or more groups, we can only measure the taxon relative abundance in specimens obtained from the ecosystems. Because the comparison of taxon relative abundance in the specimen is not equivalent to the comparison of taxon relative abundance in the ecosystems, this presents a special challenge. Second, because the relative abundance of taxa in the specimen (as well as in the ecosystem) sum to 1, these are compositional data. Because the compositional data are constrained by the simplex (sum to 1) and are not unconstrained in the Euclidean space, many standard methods of analysis are not applicable. Here, we evaluate how these challenges impact the performance of existing normalization methods and differential abundance analyses. Effects on normalization: Most normalization methods enable successful clustering of samples according to biological origin when the groups differ substantially in their overall microbial composition. Rarefying more clearly clusters samples according to biological origin than other normalization techniques do for ordination metrics based on presence or absence. Alternate normalization measures are potentially vulnerable to artifacts due to library size. Effects on differential abundance testing: We build on a previous work to evaluate seven proposed statistical methods using rarefied as well as raw data. Our simulation studies suggest that the false discovery rates of many differential abundance-testing methods are not increased by rarefying itself, although of course rarefying results in a loss of sensitivity due to elimination of a portion of available data. For groups with large (~10×) differences in the average

  12. Critical Taxonomic Appraisal of Some Taxa of Pedicularis from Indian Himalayas Belonging to Section Siphonanthae

    Directory of Open Access Journals (Sweden)

    Arti Garg

    2009-06-01

    Full Text Available The existing confusion on the taxonomic status of five taxa of Pedicularis viz. P. punctata Decne, P. siphonantha D. Don, P. hookeriana Wall. ex Benth., P. megalantha D. Don and P. hoffmeisteri Kl. ex Kl. & Garcke is resolved on the basis of critical morphological study. These taxa belong to section Siphonanthae, subgenus Longirostres. Pennell’s view of segregating these taxa into distinct species is defended and upheld.

  13. Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

    International Nuclear Information System (INIS)

    Campbell, C.E.; Knoechel, R.; Copeman, D.

    1998-01-01

    An 11-year study of the zooplankton community in Cat Arm Hydroelectric Reservoir in Newfoundland was conducted to assess long-term zooplankton community dynamics in a subarctic system. Zooplankton biomass and species compositions were monitored from 1983 to 1993. The monitoring program documented the trophic evolution of the Cat Arm system as it changed from a shallow lake with short water retention time to a deep reservoir with a much lower flushing rate. Zooplankton biomass increased approximately 19-fold in the oligotrophic hydroelectric reservoir following impoundment in 1984, relative to biomass in the preexisting lake. During the first three years of impoundment, there were no increases in either phytoplankton biomass or primary productivity. Natality of the dominant cladoceran (Daphnia catawba) did not increase. Summer water retention time increased from pre-impoundment levels of 4 days in 1983 to 338 days in 1993. The study showed that zooplankton biomass was greatly correlated with water retention time, and showed no major correlation with phytoplankton biomass, primary productivity, nutrient concentrations, pH, colour, or epilimnetic temperature. It was concluded that changes in the zooplankton community in the hydroelectric reservoir were a result of decreases in losses due to washout. 41 refs., 2 tabs., 6 figs

  14. Nematode-associated microbial taxa do not correlate with host phylogeny, geographic region or feeding morphology in marine sediment habitats.

    Science.gov (United States)

    Schuelke, Taruna; Pereira, Tiago José; Hardy, Sarah M; Bik, Holly M

    2018-04-01

    Studies of host-associated microbes are critical for advancing our understanding of ecology and evolution across diverse taxa and ecosystems. Nematode worms are ubiquitous across most habitats on earth, yet little is known about host-associated microbial assemblages within the phylum. Free-living nematodes are globally abundant and diverse in marine sediments, with species exhibiting distinct buccal cavity (mouth) morphologies that are thought to play an important role in feeding ecology and life history strategies. Here, we investigated patterns in marine nematode microbiomes, by characterizing host-associated microbial taxa in 281 worms isolated from a range of habitat types (deep-sea, shallow water, methane seeps, Lophelia coral mounds, kelp holdfasts) across three distinct geographic regions (Arctic, Southern California and Gulf of Mexico). Microbiome profiles were generated from single worms spanning 33 distinct morphological genera, using a two-gene metabarcoding approach to amplify the V4 region of the 16S ribosomal RNA (rRNA) gene targeting bacteria/archaea and the V1-V2 region of the 18S rRNA gene targeting microbial eukaryotes. Contrary to our expectations, nematode microbiome profiles demonstrated no distinct patterns either globally (across depths and ocean basins) or locally (within site); prokaryotic and eukaryotic microbial assemblages did not correlate with nematode feeding morphology, host phylogeny or morphological identity, ocean region or marine habitat type. However, fine-scale analysis of nematode microbiomes revealed a variety of novel ecological interactions, including putative parasites and symbionts, and potential associations with bacterial/archaeal taxa involved in nitrogen and methane cycling. Our results suggest that in marine habitats, free-living nematodes may utilize diverse and generalist foraging strategies that are not correlated with host genotype or feeding morphology. Furthermore, some abiotic factors such as geographic region

  15. Contrasting patterns of changes in abundance following a bleaching event between juvenile and adult scleractinian corals

    Science.gov (United States)

    Álvarez-Noriega, Mariana; Baird, Andrew H.; Bridge, Tom C. L.; Dornelas, Maria; Fontoura, Luisa; Pizarro, Oscar; Precoda, Kristin; Torres-Pulliza, Damaris; Woods, Rachael M.; Zawada, Kyle; Madin, Joshua S.

    2018-06-01

    Coral bleaching events have caused extensive mortality on reefs around the world. Juvenile corals are generally less affected by bleaching than their conspecific adults and therefore have the potential to buffer population declines and seed recovery. Here, we use juvenile and adult abundance data at 20 sites encircling Lizard Island, Great Barrier Reef, before and after the 2016 bleaching event to quantify: (1) correlates of changes in juvenile abundance following a bleaching event; (2) differences in susceptibility to extreme thermal stress between juveniles and adults. Declines in juvenile abundance were lower at sites closer to the 20-m-depth contour and higher for Acropora and Pocillopora juveniles than for other taxa. Juveniles of Acropora and Goniastrea were less susceptible to bleaching than adults, but the opposite was true for Pocillopora spp. and taxa in the family Merulinidae. Our results indicate that the potential of the juvenile life stage to act as a buffer during bleaching events is taxon-dependent.

  16. Phytoplankton response to winter warming modified by large-bodied zooplankton: an experimental microcosm study

    Directory of Open Access Journals (Sweden)

    Hu He

    2015-03-01

    Full Text Available While several field investigations have demonstrated significant effects of cool season (winter or spring warming on phytoplankton development, the role played by large-bodied zooplankton grazers for the responses of phytoplankton to winter warming is ambiguous. We conducted an outdoor experiment to compare the effect of winter warming (heating by 3°C in combination with presence and absence of Daphnia grazing (D. similis on phytoplankton standing crops and community structure under eutrophic conditions. When Daphnia were absent, warming was associated with significant increases in phytoplankton biomass and cyanobacterial dominance. In contrast, when Daphnia were present, warming effects on phytoplankton dynamics were offset by warming-enhanced grazing, resulting in no significant change in biomass or taxonomic dominance. These results emphasize that large-bodied zooplankton like Daphnia spp. may play an important role in modulating the interactions between climate warming and phytoplankton dynamics in nutrient rich lake ecosystems.

  17. Distance-decay and taxa-area relationships for bacteria, archaea and methanogenic archaea in a tropical lake sediment.

    Directory of Open Access Journals (Sweden)

    Davi Pedroni Barreto

    Full Text Available The study of of the distribution of microorganisms through space (and time allows evaluation of biogeographic patterns, like the species-area index (z. Due to their high dispersal ability, high reproduction rates and low rates of extinction microorganisms tend to be widely distributed, and they are thought to be virtually cosmopolitan and selected primarily by environmental factors. Recent studies have shown that, despite these characteristics, microorganisms may behave like larger organisms and exhibit geographical distribution. In this study, we searched patterns of spatial diversity distribution of bacteria and archaea in a contiguous environment. We collected 26 samples of a lake sediment, distributed in a nested grid, with distances between samples ranging from 0.01 m to 1000 m. The samples were analyzed using T-RFLP (Terminal restriction fragment length polymorphism targeting mcrA (coding for a subunit of methyl-coenzyme M reductase and the genes of Archaeal and Bacterial 16S rRNA. From the qualitative and quantitative results (relative abundance of operational taxonomic units we calculated the similarity index for each pair to evaluate the taxa-area and distance decay relationship slopes by linear regression. All results were significant, with mcrA genes showing the highest slope, followed by Archaeal and Bacterial 16S rRNA genes. We showed that the microorganisms of a methanogenic community, that is active in a contiguous environment, display spatial distribution and a taxa-area relationship.

  18. Incorporating breeding abundance into spatial assignments on continuous surfaces.

    Science.gov (United States)

    Rushing, Clark S; Marra, Peter P; Studds, Colin E

    2017-06-01

    Determining the geographic connections between breeding and nonbreeding populations, termed migratory connectivity, is critical to advancing our understanding of the ecology and conservation of migratory species. Assignment models based on stable isotopes historically have been an important tool for studying migratory connectivity of small-bodied species, but the low resolution of these assignments has generated interest into combining isotopes with other sources in information. Abundance is one of the most appealing data sources to include in isotope-based assignments, but there are currently no statistical methods or guidelines for optimizing the contribution of stable isotopes and abundance for inferring migratory connectivity. Using known-origin stable-hydrogen isotope samples of six Neotropical migratory bird species, we rigorously assessed the performance of assignment models that differentially weight the contribution of the isotope and abundance data. For two species with adequate sample sizes, we used Pareto optimality to determine the set of models that simultaneously minimized both assignment error rate and assignment area. We then assessed the ability of the top models from these two species to improve assignments of the remaining four species compared to assignments based on isotopes alone. We show that the increased precision of models that include abundance is often offset by a large increase in assignment error. However, models that optimally weigh the abundance data relative to the isotope data can result in higher precision and, in some cases, lower error than models based on isotopes alone. The top models, however, depended on the distribution of relative breeding abundance, with patchier distributions requiring stronger downweighting of abundance, and we present general guidelines for future studies. These results confirm that breeding abundance can be an important source of information for studies investigating broad-scale movements of

  19. Influence of a carp invasion on the zooplankton community in Laguna Medina, a Mediterranean shallow lake

    OpenAIRE

    Norbert, Florian; López-Luque, raquel; Ospina-Álvarez, Natalia; Hufnagel, Levente; Green, Andy J.

    2016-01-01

    The common carp (Cyprinus carpio) is a highly invasive species and an ecological engineer. It has been repeatedly shown to increase nutrient concentrations and phytoplankton biomass while destroying submerged macrophytes, although there are few studies from the Mediterranean region. We studied its impact on the zooplankton community in Laguna de Medina lake, a shallow lake in Jerez de la Frontera, south-west Spain. Carp were removed with rotenone in 2007 but returned in 2010-2011. ...

  20. Carbon partitioning in the food web of a high mountain lake: from bacteria to zooplankton

    Directory of Open Access Journals (Sweden)

    Alessandra PUGNETTI

    1999-08-01

    Full Text Available The organisms of the microbial loop in Lake Paione Superiore (LPS, a high mountain lake in the Italian Alpine region, were studied together with phytoplankton and zooplankton for three successive years. The biomass of bacteria, HNF (heterotrophic nanoflagellates, ciliates and phytoplankton, as mean carbon concentration in the three years, was 30 and 37 μg C l-1 near the surface (SUR and the bottom (BOT respectively. Under the ice-cover the mean biomass carbon decreased especially at the BOT, whereas at SUR the decrease was less evident due to the maintenance of higher phytoplankton biomass (mixotrophic flagellates. In LPS ~50% of the carbon was confined in bacteria, 20% in protozoa and 30% in phytoplankton. The ratio Autotrophs/Heterotrophs was lower than 1 (mean: 0,97 at SUR and 0,58 at BOT thus indicating a system with a predominance of the heterotrophs. This might be the result of light inhibition of algal growth coupled to a production of dissolved carbon, utilized by bacteria. During late summer the peak of Daphnia longispina, the main component of the zooplankton of LPS, increased the carbon content in the lake to a total of 158 and 300 μg C l-1 in 1997 and 1998 respectively. At the late summer peaks, zooplankton represented from 78 to 89% of the total carbon of the pelagic communities. Furthermore, the presence of Daphnia could be responsible for a decrease in the biomass carbon of a variety of organisms (algae, protozoa and bacteria. It may be possible that this is an instance of zooplankton grazing on algae, protozoa and also bacteria, as Daphnia has very broad niches and may eat pico-, nanoplankton and small ciliates. In the oligotrophic LPS, a diet which also includes protozoa could give Daphnia a further chance of survival, as ciliates are an important source of fatty acids and sterols.

  1. Spatial variations in zooplankton diversity in waters contaminated with composite effluents

    Directory of Open Access Journals (Sweden)

    Asitava CHATTERJEE

    2007-08-01

    Full Text Available Zooplankton species are cosmopolitan in their clean freshwater habitat and are also found in industrial and municipal wastewaters. The present study records for the first time the aspects of zooplankton diversity in relation to physico-chemical environment of five selected sites of the East Calcutta wetlands, a Ramsar site of Kolkata city, India, heavily contaminated by industrial and municipal wastewaters. The study revealed the occurrence of 22 species of zooplankton, among these 3 species of Cladocera, 2 species of Copepoda, 15 species of Rotifera, and 2 species of Ostracoda were recorded. The copepod Mesocyclops leuckarti was found in all the five sites, rotifers Asplanchna brightwelli, Brachionus angularis, B. calyciflorus and Cladocera Ceriodaphnia cornuta were found in four sites; Moina micrura and Diaphanosoma sarsi were found at three sites. Site wise variation in dominance, diversity, evenness and richness were calculated. Site 1, a fish-pond that stabilized composite wastewater, showed the maximum species richness having 17 species, while Site 2, SWF wastewater carrying canal, showed only 4 species. The calculated Jack 1 values of Sites 1 to 5 were 21.78, 3.77, 18.63, 12.5 and 16.95 respectively. Shannon-Wiener species diversity index (H/ values were almost similar for all the three relatively less polluted sites viz, Site 1 (1.959, Site 4 (2.010, Site 5 (2.047. However, at highly polluted sites viz., 2 and 3, H/ value of 1.336 and 0.984 respectively, were calculated. Simpson’s Dominance index (Dsimp value was highest at Site 3 (0.618 indicating maximum dominance, whereas at Site 5 dominance was lowest (0.1680 and diversity was highest. We discuss the role of zooplankton in the amelioration of wastewater.

  2. Changes in fish production effectivity in eutrophic fishponds of zooplankton structure

    Czech Academy of Sciences Publication Activity Database

    Potužák, J.; Hůda, J.; Pechar, Libor

    2007-01-01

    Roč. 15, - (2007), s. 201-210 ISSN 0967-6120 R&D Projects: GA MŽP(CZ) SM/640/18/03; GA MŽP(CZ) SL/1/6/04 Institutional research plan: CEZ:AV0Z60870520 Keywords : fishponds * zooplankton * eutrophication * fish management * primary production Subject RIV: GL - Fishing Impact factor: 0.828, year: 2007

  3. Effect of removal of free-floating macrophytes on zooplankton habitat in shallow wetland

    OpenAIRE

    Choi Jong-Yun; Jeong Kwang-Seuk; La Geung-Hwan; Joo Gea-Jae

    2014-01-01

    Submerged macrophytes improve the structural heterogeneity of microhabitats in aquatic ecosystems, often providing an important habitat for zooplankton. However, excessive development of free-floating macrophytes on the water surface can reduce the biomass of submerged macrophytes and result in a relatively simple habitat structure. We hypothesized that controlling the development of free-floating macrophytes would result in a more complex habitat structure by promoting the development of sub...

  4. Null models for study Rotifers and Crustaceans Zooplankton species richness in Chilean Patagonian lakes

    OpenAIRE

    Escalante, Patricio de los Ríos

    2016-01-01

    Abstract Aims The Patagonian lakes are characterized by their oligotrophy that is the cause of low species number in their zooplankton assemblage. The aim of the present study is to analyze the crustacean and rotifers species number pattern in Patagonian lakes among a latitudinal gradient (40-51 °S). Results The results revealed that there are direct significant correlations between total species with rotifer species, and chlorophyll concentration with crustacean species number, and an inve...

  5. Zooplankton standing stock assessment and fishery resources in the indian seas

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Sarupria, J.S.; Bhargava, R.M.S.

    of Bengal, Lakshadweep (Laccadive) Sea and Andaman Sea. The zooplankton biomass values fluctuated between 0.1 to 12 ml m sup(-3) (av. = 0.664 plus or minus 1.36 ml m sup(-3)), 0.1 to 8.0 ml m sup(-3) (av. = 0.355 plus or minus 0.761 ml m sup(-3)), 0.1 to 1...

  6. Zooplankton biomass and potential fishery resources of the EEZ of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    , Lakshadweep (Laccadive) and Andaman and Nicobar seas. Zooplankton biomass values ranged from 0.02 to 20.0 ml m sup(-3) (av. = 0.82 ml m sup(-3)); 0.01 to 5.3 ml m sup(-3) (av. = 0.22 ml m sup(-3)); 0.01 to 1.6 ml m sup(-3) (av. = 0.82 ml m sup(-3) and 0.2 to 0...

  7. Zooplankton nutrition study under conditions close to natural with the use of radioactive phosphorus

    OpenAIRE

    Pavlovskaya, T; Zesenko, A

    1984-01-01

    Lack of a sensitive method for in situ study of the nutrition quantitative characteristics (and food balance in particular) for zooplankton populations in low-productivity regions was the reason for developing one. For the basis of such a method the authors selected the property of radioactive phosphorus isotopes of fast and effective embedding into all plankton components. The method described above allowed not only to quantitatively determine the consumption and transportation of a substanc...

  8. Metal and proton toxicity to lake zooplankton: A chemical speciation based modelling approach

    Czech Academy of Sciences Publication Activity Database

    Stockdale, A.; Tipping, E.; Lofts, S.; Fott, J.; Garmo, Ø.; Hruška, Jakub; Keller, B.; Löfgren, S.; Maberlyh, S.; Majer, V.; Nierzwicki-Bauer, S. A.; Persson, G.; Schartau, A.; Thackeray, S. J.; Valois, A.; Vrba, Jaroslav; Walseng, B.; Yan, N.

    2014-01-01

    Roč. 186, MAR (2014), s. 115-125 ISSN 0269-7491 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA ČR GA206/07/1200 Institutional support: RVO:67179843 ; RVO:60077344 Keywords : chemical speciation * bioavailability * recovery * crustacean zooplankton * lakes Subject RIV: EH - Ecology, Behaviour Impact factor: 4.143, year: 2014

  9. Twilight of Abundance

    Science.gov (United States)

    Archibald, David

    2014-03-01

    Baby boomers enjoyed the most benign period in human history: fifty years of relative peace, cheap energy, plentiful grain supply, and a warming climate due to the highest solar activity for 8,000 years. The party is over - prepare for the twilight of abundance. David Archibald reveals the grim future the world faces on its current trajectory: massive fuel shortages, the bloodiest warfare in human history, a global starvation crisis, and a rapidly cooling planet. Archibald combines pioneering science with keen economic knowledge to predict the global disasters that could destroy civilization as we know it - disasters that are waiting just around the corner. But there's good news, too: We can have a good future if we prepare for it. Advanced, civilized countries can have a permanently high standard of living if they choose to invest in the technologies that will get them there. Archibald, a climate scientist as well as an inventor and a financial specialist, explains which scientific breakthroughs can save civilization in the coming crisis - if we can cut through the special interest opposition to these innovations and allow free markets to flourish.

  10. DNA barcode data accurately assign higher spider taxa

    Directory of Open Access Journals (Sweden)

    Jonathan A. Coddington

    2016-07-01

    Full Text Available The use of unique DNA sequences as a method for taxonomic identification is no longer fundamentally controversial, even though debate continues on the best markers, methods, and technology to use. Although both existing databanks such as GenBank and BOLD, as well as reference taxonomies, are imperfect, in best case scenarios “barcodes” (whether single or multiple, organelle or nuclear, loci clearly are an increasingly fast and inexpensive method of identification, especially as compared to manual identification of unknowns by increasingly rare expert taxonomists. Because most species on Earth are undescribed, a complete reference database at the species level is impractical in the near term. The question therefore arises whether unidentified species can, using DNA barcodes, be accurately assigned to more inclusive groups such as genera and families—taxonomic ranks of putatively monophyletic groups for which the global inventory is more complete and stable. We used a carefully chosen test library of CO1 sequences from 49 families, 313 genera, and 816 species of spiders to assess the accuracy of genus and family-level assignment. We used BLAST queries of each sequence against the entire library and got the top ten hits. The percent sequence identity was reported from these hits (PIdent, range 75–100%. Accurate assignment of higher taxa (PIdent above which errors totaled less than 5% occurred for genera at PIdent values >95 and families at PIdent values ≥ 91, suggesting these as heuristic thresholds for accurate generic and familial identifications in spiders. Accuracy of identification increases with numbers of species/genus and genera/family in the library; above five genera per family and fifteen species per genus all higher taxon assignments were correct. We propose that using percent sequence identity between conventional barcode sequences may be a feasible and reasonably accurate method to identify animals to family/genus. However

  11. Estimation of the toxicity of pollutants to marine phytoplanktonic and zooplanktonic organisms

    International Nuclear Information System (INIS)

    1989-01-01

    One of the basic components of the action plans sponsored by UNEP in the framework of the Regional Seas Programme is the assessment of the state of the marine environment and of its resources, and of the sources and trends of the pollution, and the impact of pollution on human health, marine ecosystems, and amenities. In order to ensure that the data obtained through this assessment can be compared on a world-wide basis and thus contribute to the Global Environment Monitoring System (GEMS) of UNEP, a set of Reference Methods and Guidelines for marine pollution studies are being developed as part of a programme of comprehensive technical support which includes the provision of expert advice, reference methods and materials, training and data quality assurance. This reference method describes procedures for estimating the toxicity of pollutants to marine phytoplankton and zooplankton. Procedures are given for estimating the media effective concentrations (EC50) of toxicants to phytoplankton, and the minimum algistatic concentration (MAC-5). For zooplankton, procedures are given for determining median lethal concentrations. Organisms are exposed to each of a range of concentrations of the test substance. For phytoplankton, the median effective concentration (EC50) is estimated in terms of the number of individuals surviving, the biomass of individuals surviving, or the chlorophyll content of the individuals surviving. For zooplankton, the media lethal concentration (LC50) is estimated by conventional log-probit analysis of the mortality data

  12. A simple and efficient total genomic DNA extraction method for individual zooplankton.

    Science.gov (United States)

    Fazhan, Hanafiah; Waiho, Khor; Shahreza, Md Sheriff

    2016-01-01

    Molecular approaches are widely applied in species identification and taxonomic studies of minute zooplankton. One of the most focused zooplankton nowadays is from Subclass Copepoda. Accurate species identification of all life stages of the generally small sized copepods through molecular analysis is important, especially in taxonomic and systematic assessment of harpacticoid copepod populations and to understand their dynamics within the marine community. However, total genomic DNA (TGDNA) extraction from individual harpacticoid copepods can be problematic due to their small size and epibenthic behavior. In this research, six TGDNA extraction methods done on individual harpacticoid copepods were compared. The first new simple, feasible, efficient and consistent TGDNA extraction method was designed and compared with the commercial kit and modified available TGDNA extraction methods. The newly described TGDNA extraction method, "Incubation in PCR buffer" method, yielded good and consistent results based on the high success rate of PCR amplification (82%) compared to other methods. Coupled with its relatively consistent and economical method the "Incubation in PCR buffer" method is highly recommended in the TGDNA extraction of other minute zooplankton species.

  13. Cyanobacteria dominance influences resource use efficiency and community turnover in phytoplankton and zooplankton communities.

    Science.gov (United States)

    Filstrup, Christopher T; Hillebrand, Helmut; Heathcote, Adam J; Harpole, W Stanley; Downing, John A

    2014-04-01

    Freshwater biodiversity loss potentially disrupts ecosystem services related to water quality and may negatively impact ecosystem functioning and temporal community turnover. We analysed a data set containing phytoplankton and zooplankton community data from 131 lakes through 9 years in an agricultural region to test predictions that plankton communities with low biodiversity are less efficient in their use of limiting resources and display greater community turnover (measured as community dissimilarity). Phytoplankton resource use efficiency (RUE = biomass per unit resource) was negatively related to phytoplankton evenness (measured as Pielou's evenness), whereas zooplankton RUE was positively related to phytoplankton evenness. Phytoplankton and zooplankton RUE were high and low, respectively, when Cyanobacteria, especially Microcystis sp., dominated. Phytoplankton communities displayed slower community turnover rates when dominated by few genera. Our findings, which counter findings of many terrestrial studies, suggest that Cyanobacteria dominance may play important roles in ecosystem functioning and community turnover in nutrient-enriched lakes. © 2014 John Wiley & Sons Ltd/CNRS.

  14. Imazethapyr and imazapic, bispyribac-sodium and penoxsulam: Zooplankton and dissipation in subtropical rice paddy water

    Energy Technology Data Exchange (ETDEWEB)

    Reimche, Geovane B., E-mail: geovane_reimche@yahoo.com.br [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Machado, Sérgio L.O. [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Oliveira, Maria Angélica [Department of Biology, Federal University of Santa Maria, Santa Maria, RS (Brazil); Zanella, Renato; Dressler, Valderi Luiz; Flores, Erico M.M. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil); Gonçalves, Fábio F. [School of Chemistry and Food, Federal Foundation University of Rio Grande (FURG), 95500-000 Santo Antônio da Patrulha, RS (Brazil); Donato, Filipe F.; Nunes, Matheus A.G. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil)

    2015-05-01

    Herbicides are very effective at eliminating weed and are largely used in rice paddy around the world, playing a fundamental role in maximizing yield. Therefore, considering the flooded environment of rice paddies, it is necessary to understand the side effects on non-target species. Field experiment studies were carried out during two rice growing seasons in order to address how the commonly-used herbicides imazethapyr and imazapic, bispyribac-sodium and penoxsulam, used at recommended dosage, affect water quality and the non-target zooplankton community using outdoor rice field microcosm set-up. The shortest (4.9 days) and longest (12.2 days) herbicide half-life mean, estimated of the dissipation rate (k) is shown for imazethapyr and bispyribac-sodium, respectively. Some water quality parameters (pH, conductivity, hardness, BOD{sub 5}, boron, potassium, magnesium, phosphorus and chlorides) achieved slightly higher values at the herbicide treatment. Zooplankton community usually quickly recovered from the tested herbicide impact. Generally, herbicides led to an increase of cladocera, copepods and nauplius population, while rotifer population decreased, with recovery at the end of the experiment (88 days after herbicide treatment). - Highlights: • Selective herbicides in paddy rice fields, do not affect water quality. • Zooplankton communities show good response with herbicide dissipation. • The use of commercial herbicide mixture has strong effects on freshwater Rotifers.

  15. Modeled sensitivity of Lake Michigan productivity and zooplankton to changing nutrient concentrations and quagga mussels

    Science.gov (United States)

    Pilcher, Darren J.; McKinley, Galen A.; Kralj, James; Bootsma, Harvey A.; Reavie, Euan D.

    2017-08-01

    The recent decline in Lake Michigan productivity is often attributed to filter feeding by invasive quagga mussels, but some studies also implicate reductions in lakewide nutrient concentrations. We use a 3-D coupled hydrodynamic-biogeochemical model to evaluate the effect of changing nutrient concentrations and quagga mussel filtering on phytoplankton production and phytoplankton and zooplankton biomass. Sensitivity experiments are used to assess the net effect of each change separately and in unison. Quagga mussels are found to have the greatest impact during periods of isothermal mixing, while nutrients have the greatest impact during thermal stratification. Quagga mussels also act to enhance spatial heterogeneity, particularly between nearshore-offshore regions. This effect produces a reversal in the gradient of nearshore-offshore productivity: from relatively greater nearshore productivity in the prequagga lake to relatively lesser nearshore productivity after quaggas. The combined impact of both processes drives substantial reductions in phytoplankton and zooplankton biomass, as well as significant modifications to the seasonality of surface water pCO2, particularly in nearshore regions where mussel grazing continues year-round. These results support growing concern that considerable losses of phytoplankton and zooplankton will yield concurrent losses at higher trophic levels. Comparisons to observed productivity suggest that both quagga mussel filtration and lower lakewide total phosphorus are necessary to accurately simulate recent changes in primary productivity in Lake Michigan.

  16. [Phytoplankton and zooplankton of the industrial reservoir R-9 (Lake Karachay)].

    Science.gov (United States)

    Priakhin, E A; Triapitsina, G A; Atamaniuk, N I; Osipov, D I; Stukalov, P M; Ivanov, I A; Popova, I Ia; Akleev, A V

    2012-01-01

    Planktonic communities of the Reservoir-9 (Lake Karachay, storage reservoir of liquid medium-level radioactive waste of the Mayak Production Association) are exposed to the severe radioactive forcing (in 2010 the total beta-activity of the water was 1.8 x 10(7) Bq/L, total alpha-activity was 1.1 x 10(4) Bq/L), aswell as to the chemical contamination (level of nitrates in water 4.1 g/L). The calculated values of the absorbed dose rate were 130 Gy/day for phytoplankton and 4.0 Gy/day for zooplankton. Extremely low species diversity, the overwhelming dominance of one species (phytoplankton is close to a monoculture of ubiquitous cyanobacteria Geitlerinema amphibium, zooplankton--to a monoculture of rotifers Hexarthrafennica), wide fluctuations in numbers of algae, a low number of zooplankton were the most substantial characteristics of the plankton communities in Lake Karachay. So, plankton communities status is a sign of environmental retrogress in this ecosystem.

  17. Effect of planktivores, zooplankton, and macrobenthos on material flow in a small lake

    International Nuclear Information System (INIS)

    Starkel, W.M.

    1985-01-01

    Planktivores, zooplankton grazers, and macrobenthos were studied to determine how changes in animal community structure may alter the flow of material in Dunham Pond, CT. Chaoborus and chironomid larvae were studied to determine how they affect the flux of matter across the sediment/water interface. This was done by incubating undisturbed cores in situ and relating changes in water chemistry to larval density. The log-transformed flux rates of iron, manganese, and phosphorus were linearly related to larval biomass. Functional groups may be successfully used to predict rates of material flow. Changes in the mass of macroinvertebrates affect the flux rates of redox-active substances across the sediment/water interface. The use of population densities and feeding characteristics to estimate trophic transfer in Dunham Pond indicate that (1) visual planktivory by larval perch may result in overutilization of prey, (2) ambush planktivory by univoltine Chaoborus appears to under utilize prey, and (3) zooplankton grazing tracks net primary productivity, regardless of zooplankton community structure. Animal groups cycle 30-100% of the phosphorus required for 14 C productivity in Dunham Pond

  18. Water Browning Influences the Behavioral Effects of Ultraviolet Radiation on Zooplankton

    Directory of Open Access Journals (Sweden)

    Raoul Wolf

    2018-03-01

    Full Text Available In the last decades, limnic water bodies in the Northern hemisphere have experienced a noticeable browning, i.e., increasing levels of dissolved organic matter (DOM. While the effects on primary producers is usually considered negative (light attenuation, zooplankton is thought to benefit from increased DOM, which absorbs harmful ultraviolet radiation (UVR. However, behavioral alterations due to browning in zooplankton have not yet been studied. We investigated the effects of a DOM gradient, alone and in combination with UVR, on the swimming behavior of Daphnia magna. Making use of a computer-controlled imaging system, we repeatedly filmed individuals over 6 h and analyzed the video material to unravel effects on exploration behavior and other motility patterns. The results show that increasing DOM buffers the detrimental effects of UVR on swimming behavior. This is likely due to attenuation of UVR by DOM. Interestingly, DOM also raised the overall swimming activity independent of UVR exposure. Our findings highlight the importance of DOM in freshwater systems, not only because of its physico-chemical properties, but also due to its higher-level effects on zooplankton communities.

  19. Changes in Abundance of Oral Microbiota Associated with Oral Cancer

    Science.gov (United States)

    Schmidt, Brian L.; Kuczynski, Justin; Bhattacharya, Aditi; Huey, Bing; Corby, Patricia M.; Queiroz, Erica L. S.; Nightingale, Kira; Kerr, A. Ross; DeLacure, Mark D.; Veeramachaneni, Ratna; Olshen, Adam B.; Albertson, Donna G.

    2014-01-01

    Individual bacteria and shifts in the composition of the microbiome have been associated with human diseases including cancer. To investigate changes in the microbiome associated with oral cancers, we profiled cancers and anatomically matched contralateral normal tissue from the same patient by sequencing 16S rDNA hypervariable region amplicons. In cancer samples from both a discovery and a subsequent confirmation cohort, abundance of Firmicutes (especially Streptococcus) and Actinobacteria (especially Rothia) was significantly decreased relative to contralateral normal samples from the same patient. Significant decreases in abundance of these phyla were observed for pre-cancers, but not when comparing samples from contralateral sites (tongue and floor of mouth) from healthy individuals. Weighted UniFrac principal coordinates analysis based on 12 taxa separated most cancers from other samples with greatest separation of node positive cases. These studies begin to develop a framework for exploiting the oral microbiome for monitoring oral cancer development, progression and recurrence. PMID:24887397

  20. A conformação estrutural da taxa de juros

    OpenAIRE

    Reinert, José Nilson

    2010-01-01

    Trata da conformação da taxa de juros no longo prazo. Aborda o tema dentro da teoria marxista e apresenta o volume de reservas formadas ao longo dos ciclos econômicos como determinante principal da taxa de juros. Analisa dados da economia norte-americana, visando ilustrar as hopóteses apresentadas.

  1. Climate, vegetation, distribution of taxa and diversity: A synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Nazrul-Islam, A K.M. [Ecology Laboratory, Department of Botany, University of Dhaka, Dhaka (Bangladesh); Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

    2005-07-15

    An attempt has been made to investigate from a range of viewpoints the principle of the climatic control of plant distribution. The accumulated plant weight (w) is related to the incoming solar radiation (S) and is dependent on leaf area index, the incoming solar radiation and the efficiency of solar radiation to dry matter conversion. A review is presented and a model is discussed in order to stimulate interest and knowledge in this crucial and central theme of ecology. The aim is to develop a model based on eco-physiological principles to predict the major vegetational zones of the globe. Predictions were based on various plant responses, such as low temperature survival and evapo-transpiration. Taxonomic diversity declined in a poleward direction; for both the northern and southern hemispheres family diversity is greatest near the equator, declined markedly from latitude 30 deg. to 90 deg. Strong correlation between family diversity and absolute minimum temperature exists and a regression line suggests a decrease of 3.3 families per deg. C reductions in minimum temperature. Analysis of the islands ecology differing in areas at various altitudes of the present and past has been most productive in providing means of investigating dispersal and migration and vertical diversity. Experimental studies have been attempted in herbaceous vegetation at different latitudes (tundra and British Isles) by clearing the native species (Carex bigelowii, Eriphorum vaginatum) of the area and by introducing exotic species such as Lolium perenne. The cover of the exotic species subsequently declined and ultimately became extinct and was covered by the native species. In order to investigate the climatic control of the distribution of taxa it becomes necessary to split the life (life cycles) of a plant into a number of stages, each of which is a link in the chain of survival and each of which can dominate the control of distribution. When a stage of life cycle is broken then

  2. Climate, vegetation, distribution of taxa and diversity: A synthesis

    International Nuclear Information System (INIS)

    Nazrul-Islam, A.K.M.

    2005-07-01

    An attempt has been made to investigate from a range of viewpoints the principle of the climatic control of plant distribution. The accumulated plant weight (w) is related to the incoming solar radiation (S) and is dependent on leaf area index, the incoming solar radiation and the efficiency of solar radiation to dry matter conversion. A review is presented and a model is discussed in order to stimulate interest and knowledge in this crucial and central theme of ecology. The aim is to develop a model based on eco-physiological principles to predict the major vegetational zones of the globe. Predictions were based on various plant responses, such as low temperature survival and evapo-transpiration. Taxonomic diversity declined in a poleward direction; for both the northern and southern hemispheres family diversity is greatest near the equator, declined markedly from latitude 30 deg. to 90 deg. Strong correlation between family diversity and absolute minimum temperature exists and a regression line suggests a decrease of 3.3 families per deg. C reductions in minimum temperature. Analysis of the islands ecology differing in areas at various altitudes of the present and past has been most productive in providing means of investigating dispersal and migration and vertical diversity. Experimental studies have been attempted in herbaceous vegetation at different latitudes (tundra and British Isles) by clearing the native species (Carex bigelowii, Eriphorum vaginatum) of the area and by introducing exotic species such as Lolium perenne. The cover of the exotic species subsequently declined and ultimately became extinct and was covered by the native species. In order to investigate the climatic control of the distribution of taxa it becomes necessary to split the life (life cycles) of a plant into a number of stages, each of which is a link in the chain of survival and each of which can dominate the control of distribution. When a stage of life cycle is broken then

  3. Energy abundance and economic progress

    International Nuclear Information System (INIS)

    Schurr, S.H.

    1983-01-01

    A discussion is presented on the benefits of energy abundance and on the links between energy supply, economic growth and human welfare in the United States. It is argued that the restoration of energy abundance with dependable sources of supply should be a major national objective. (U.K.)

  4. Abundances in the Galactic bulge

    Energy Technology Data Exchange (ETDEWEB)

    Barbuy, B; Alves-Brito, A [Universidade de Sao Paulo, IAG, Rua do Matao 1226, Sao Paulo 05508-900 (Brazil); Ortolani, S; Zoccali, M [Dipartimento di Astronomia, Universita di Padova, Vicolo dell' Osservatorio 2, I-35122 Padova (Italy); Hill, V; Gomez, A [Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Melendez, J [Centro de AstrofIsica da Universidade de Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Asplund, M [Max Planck Institute for Astrophysics, Postfach 1317, 85741 Garching (Germany); Bica, E [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, CP 15051, Porto Alegre 91501-970 (Brazil); Renzini, A [Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Minniti, D [Department of Astronomy and Astrophysics, Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)], E-mail: barbuy@astro.iag.usp.br

    2008-12-15

    The metallicity distribution and abundance ratios of the Galactic bulge are reviewed. Issues raised by recent work of different groups, in particular the high metallicity end, the overabundance of {alpha}-elements in the bulge relative to the thick disc and the measurement of giants versus dwarfs, are discussed. Abundances in the old moderately metal-poor bulge globular clusters are described.

  5. In situ camera observations reveal major role of zooplankton in modulating marine snow formation during an upwelling-induced plankton bloom

    Science.gov (United States)

    Taucher, Jan; Stange, Paul; Algueró-Muñiz, María; Bach, Lennart T.; Nauendorf, Alice; Kolzenburg, Regina; Büdenbender, Jan; Riebesell, Ulf

    2018-05-01

    Particle aggregation and the consequent formation of marine snow alter important properties of biogenic particles (size, sinking rate, degradability), thus playing a key role in controlling the vertical flux of organic matter to the deep ocean. However, there are still large uncertainties about rates and mechanisms of particle aggregation, as well as the role of plankton community structure in modifying biomass transfer from small particles to large fast-sinking aggregates. Here we present data from a high-resolution underwater camera system that we used to observe particle size distributions and formation of marine snow (aggregates >0.5 mm) over the course of a 9-week in situ mesocosm experiment in the Eastern Subtropical North Atlantic. After an oligotrophic phase of almost 4 weeks, addition of nutrient-rich deep water (650 m) initiated the development of a pronounced diatom bloom and the subsequent formation of large marine snow aggregates in all 8 mesocosms. We observed a substantial time lag between the peaks of chlorophyll a and marine snow biovolume of 9-12 days, which is much longer than previously reported and indicates a marked temporal decoupling of phytoplankton growth and marine snow formation during our study. Despite this time lag, our observations revealed substantial transfer of biomass from small particle sizes (single phytoplankton cells and chains) to marine snow aggregates of up to 2.5 mm diameter (ESD), with most of the biovolume being contained in the 0.5-1 mm size range. Notably, the abundance and community composition of mesozooplankton had a substantial influence on the temporal development of particle size spectra and formation of marine snow aggregates: While higher copepod abundances were related to reduced aggregate formation and biomass transfer towards larger particle sizes, the presence of appendicularia and doliolids enhanced formation of large marine snow. Furthermore, we combined in situ particle size distributions with

  6. [Effects of large bio-manipulation fish pen on community structure of crustacean zooplankton in Meiliang Bay of Taihu Lake].

    Science.gov (United States)

    Ke, Zhi-Xin; Xie, Ping; Guo, Long-Gen; Xu, Jun; Zhou, Qiong

    2012-08-01

    In 2005, a large bio-manipulation pen with the stock of silver carp and bighead carp was built to control the cyanobacterial bloom in Meiliang Bay of Taihu Lake. This paper investigated the seasonal variation of the community structure of crustacean zooplankton and the water quality within and outside the pen. There were no significant differences in the environmental parameters and phytoplankton biomass within and outside the pen. The species composition and seasonal dynamics of crustacean zooplankton within and outside the pen were similar, but the biomass of crustacean zooplankton was greatly suppressed by silver carp and bighead carp. The total crustacean zooplankton biomass and cladocerans biomass were significantly lower in the pen (P < 0.05). In general, silver carp and bighead carp exerted more pressure on cladoceran species than on copepod species. A distinct seasonal succession of crustacean zooplankton was observed in the Bay. Many crustacean species were only dominated in given seasons. Large-sized crustacean (mainly Daphnia sp. and Cyclops vicnus) dominated in winter and spring, while small-sized species (mainly Bosmina sp., Ceriodaphnia cornuta, and Limnoithona sinensis) dominated in summer and autumn. Canonical correspondence analysis showed that water transparency, temperature, and phytoplankton biomass were the most important factors affecting the seasonal succession of the crustacean.

  7. Ichthyoplankton distribution and abundance off southeastern and southern Brazil

    Directory of Open Access Journals (Sweden)

    Débora Martins de Freitas

    2004-08-01

    Full Text Available This study describes the distribution of fish eggs and larvae along the southeastern and southern Brazilian coast. Plankton samples were collected at 85 stations using a Bongo net, and water salinity and temperature were profiled with a CTD. Results showed that fish eggs and larvae, and zooplankton biovolume were distributed in coastal waters with mean temperature of 23ºC and salinity between 33 and 34. The largest egg abundance occurred along Iguape (24º'S with a partial overlap with zooplankton biovolume and fish larvae were most abundant near shore close to Santos (24ºS. These protected coastal waters presented a surface layer with lower salinity and higher temperatures, while the bottom layer had cooler water. Ichthyoplankton abundance was low off Cabo Frio (22º'S, while a maximum in fish eggs occurred around Cabo Santa Marta Grande (28ºS.A abundância de ovos e larvas de peixes serve como um indicador do tamanho do estoque desovante, e a variabilidade nestes parâmetros está associada a flutuações no recrutamento de recursos pesqueiros. No sul e sudeste do Brasil a distribuição do ictioplâncton é influenciada pela dinâmica da Confluência Subtropical, pelo aporte de água doce e pela ação do vento na camada superficial do oceano. Este trabalho tem como objetivo descrever a distribuição de ovos e larvas de peixes ao longo da área compreendida entre Cabo Frio (22º'S e o Cabo de Santa Marta Grande (28ºS, entre 15/11 e 05/12/95. Em 85 estações foram coletadas amostras de plâncton com uma rede Bongo de 60cm de diâmetro e 330m m de malha, dotada de fluxômetro e arrastada obliquamente. Salinidade e temperatura foram obtidas em cada estação com um CTD. O maior número de ovos e larvas de peixes e biovolume de zooplâncton foram encontrados em áreas distintas na região costeira, em temperaturas entre 23 e 24ºC e salinidades entre 33 e 34. As larvas foram mais abundantes na costa de Santos; os

  8. COSPEDTree: COuplet Supertree by Equivalence Partitioning of Taxa Set and DAG Formation.

    Science.gov (United States)

    Bhattacharyya, Sourya; Mukherjee, Jayanta

    2015-01-01

    From a set of phylogenetic trees with overlapping taxa set, a supertree exhibits evolutionary relationships among all input taxa. The key is to resolve the contradictory relationships with respect to input trees, between individual taxa subsets. Formulation of this NP hard problem employs either local search heuristics to reduce tree search space, or resolves the conflicts with respect to fixed or varying size subtree level decompositions. Different approximation techniques produce supertrees with considerable performance variations. Moreover, the majority of the algorithms involve high computational complexity, thus not suitable for use on large biological data sets. Current study presents COSPEDTree, a novel method for supertree construction. The technique resolves source tree conflicts by analyzing couplet (taxa pair) relationships for each source trees. Subsequently, individual taxa pairs are resolved with a single relation. To prioritize the consensus relations among individual taxa pairs for resolving them, greedy scoring is employed to assign higher score values for the consensus relations among a taxa pair. Selected set of relations resolving individual taxa pairs is subsequently used to construct a directed acyclic graph (DAG). Vertices of DAG represents a taxa subset inferred from the same speciation event. Thus, COSPEDTree can generate non-binary supertrees as well. Depth first traversal on this DAG yields final supertree. According to the performance metrics on branch dissimilarities (such as FP, FN and RF), COSPEDTree produces mostly conservative, well resolved supertrees. Specifically, RF metrics are mostly lower compared to the reference approaches, and FP values are lower apart from only strictly conservative (or veto) approaches. COSPEDTree has worst case time and space complexities of cubic and quadratic order, respectively, better or comparable to the reference approaches. Such high performance and low computational costs enable COSPEDTree to be

  9. Zooplankton, temperature, salinity, and nutrients data from bottle and net casts in the Flores Sea from the SAMUDERA from 14 July 1976 to 26 July 1976 (NODC Accession 0000672)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, phytoplankton, nutrients, and other data were collected using bottles and nets from the SAMUDERA from 14 July 1976 to 26 July 1976 . Zooplankton data...

  10. Previsão da taxa de juros utilizando o modelo de Vasicek

    OpenAIRE

    Schoof, Hagen

    2011-01-01

    Este trabalho estuda a previsão da taxa de juros com foco em uma estratégia de investimento. Inicialmente é feita a parametrização da taxa de juros com o modelo de Vasicek para posterior aplicação do modelo autorregressivo tanto na taxa de juros quanto nos parâmetros do Vasicek. O instrumento financeiro escolhido para verificar a eficácia da metodologia proposta foi o constant matutity swap aplicado em alguns vértices. Os resultados variaram significativamente para os diferentes horizontes de...

  11. Recovery after local extinction: factors affecting re-establishment of alpine lake zooplankton.

    Science.gov (United States)

    Knapp, Roland A; Sarnelle, Orlando

    2008-12-01

    The introduction of fishes into naturally fishless mountain lakes often results in the extirpation of large-bodied zooplankton species. The ability to predict whether or not particular species will recover following fish removal is critically important for the design and implementation of lake restoration efforts but is currently not possible because of a lack of information on what factors affect recovery. The objective of this study was to identify the factors influencing recovery probability in two large-bodied zooplankton species following fish removal. We predicted that (1) Daphnia melanica would have a higher probability of recovery than Hesperodiaptomus shoshone due to differences in reproductive mode (D. melanica is parthenogenetic, H. shoshone is obligately sexual), (2) recovery probability would be a decreasing function of fish residence time due to the negative relationship between fish residence time and size of the egg bank, and (3) recovery probability would be an increasing function of lake depth as a consequence of a positive relationship between lake depth and egg bank size. To test these predictions, we sampled contemporary zooplankton populations and collected paleolimnological data from 44 naturally fishless lakes that were stocked with trout for varying lengths of time before reverting to a fishless condition. D. melanica had a significantly higher probability of recovery than did H. shoshone (0.82 vs. 0.54, respectively). The probability of recovery for H. shoshone was also significantly influenced by lake depth, fish residence time, and elevation, but only elevation influenced the probability of recovery in D. melanica. These results are consistent with between-species differences in reproductive mode combined with the much greater longevity of diapausing eggs in D. melanica than in H. shoshone. Our data also suggest that H. shoshone will often fail to recover in lakes with fish residence times exceeding 50 years.

  12. Real-time PCR and microscopy: Are the two methods measuring the same unit of arbuscular mycorrhizal fungal abundance?

    NARCIS (Netherlands)

    Gamper, H.A.; Young, J.P.W.; Jones, D.L.; Hodge, A.

    2008-01-01

    To enable quantification of mycelial abundance in mixed-species environments, eight new TaqMan® real-time PCR assays were developed for five arbuscular mycorrhizal fungal (AMF, Glomeromycota) taxa. The assays targeted genes encoding 18S rRNA or actin, and were tested on DNA from cloned gene

  13. Oxygen abundances in halo stars

    Science.gov (United States)

    Bessell, Michael S.; Sutherland, Ralph S.; Ruan, Kui

    1991-12-01

    The present study determines the oxygen abundance for a sample of metal-poor G dwarfs by analysis of OH lines between 3080 and 3200 A and the permitted high-excitation far-red O I triple. The oxygen abundances determined from the low-excitation OH lines are up to 0.55 dex lower than those measured from the high-excitation O I lines. The abundances for the far-red O I triplet lines agree with those rederived from Abia and Rebolo (1989), and the abundances from the OH lines in dwarfs and giants are in agreement with the rederived O abundances of Barbuy (1988) and others from the forbidden resonance O I line. Because the chi = 0.1.7 eV OH lines are formed in the same layers as the majority of Fe, Ti, and other neutral metal lines used for abundance analyses, it is argued that the OH lines and the forbidden O I line yield the true oxygen abundances relative to the metals.

  14. Is Recovery of Large-Bodied Zooplankton after Nutrient Loading Reduction Hampered by Climate Warming? A Long-Term Study of Shallow Hypertrophic Lake Sobygaard, Denmark

    DEFF Research Database (Denmark)

    Florencia Gutierrez, Maria; Devercelli, Melina; Brucet Balmana, Sandra

    2016-01-01

    biomass of cladocerans increased coinciding with a diminished fish catch per unit effort (CPUE), and likely then an overall reduction in the predation on zooplankton. A cascading effect to phytoplankton was evidenced by enhanced zooplankton: phytoplankton and cladoceran: phytoplankton ratios...... on phytoplankton through an expected diminished fish CPUE related to nutrient loading reduction....

  15. Zooplankton as an early warning system of persistent organic pollutants contamination in a deep lake (lake Iseo, Northern Italy

    Directory of Open Access Journals (Sweden)

    Silvia Quadroni

    2012-07-01

    Full Text Available The lake Iseo has been recently contaminated by DDT residues, originated from the melting of a glacier that released the pollutants accumulated in the past. Because of this recent input, DDT residues concentrations rose more quickly in zooplankton than in fish during 2009. In autumn 2010 the ratio drastically dropped to one–two for all the compounds indicating that the glacial DDT load should have been ceased. The situation was different for PCBs that were released to a much lower extent from glaciers. The PCB 138 ratio between zooplankton and fish was always around one–two in both years. As the zooplankton response to pollution changes resulted particularly prompt, our research highlights the importance of this component as an early warning bioindicator of hydrophobic pollutants.

  16. Analyzing the trophic link between the mesopelagic microbial loop and zooplankton from observed depth profiles of bacteria and protozoa

    Directory of Open Access Journals (Sweden)

    T. Tanaka

    2005-01-01

    Full Text Available It is widely recognized that organic carbon exported to the ocean aphotic layer is significantly consumed by heterotrophic organisms such as bacteria and zooplankton in the mesopelagic layer. However, very little is known for the trophic link between bacteria and zooplankton or the function of the microbial loop in this layer. In the northwestern Mediterranean, recent studies have shown that viruses, bacteria, heterotrophic nanoflagellates, and ciliates distribute down to 2000 m with group-specific depth-dependent decreases, and that bacterial production decreases with depth down to 1000 m. Here we show that such data can be analyzed using a simple steady-state food chain model to quantify the carbon flow from bacteria to zooplankton over the mesopelagic layer. The model indicates that bacterial mortality by viruses is similar to or 1.5 times greater than that by heterotrophic nanoflagellates, and that heterotrophic nanoflagellates transfer little of bacterial production to higher trophic levels.

  17. Interactions between piscivores, zooplanktivores and zooplankton in submerged macrophytes : Preliminary observations from enclosure and pond experiments

    DEFF Research Database (Denmark)

    Jacobsen, Lene; Perrow, M.R.; Landkildehus, F.

    1997-01-01

    behavioural changes of zooplanktivores has received little attention, even though this may be an important mechanism in enhancing the stability of submerged macrophytes in shallow lakes. Preliminary observations from an unreplicated large-scale field enclosure experiment and a replicated pond experiment...... and the presence of zooplanktivores typically changed the habitat selection of cladoceran zooplankton. In the case of piscivore/zooplanktivore interactions, the risk of predation was enough to generate clear responses even where the losses to predation were low. However, only in the enclosure experiment...

  18. L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, J.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bowen, M. [Normandeau Associates, Inc., New Ellenton, SC (United States)

    1992-03-01

    The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ``Balanced Biological Community`` (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake.

  19. L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

    International Nuclear Information System (INIS)

    Bowers, J.A.; Bowen, M.

    1992-03-01

    The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ''Balanced Biological Community'' (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake

  20. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    B. KOZLOWSKY-SUZUKI

    Full Text Available Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.