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Sample records for abundant zooplankton taxa

  1. List of Zooplankton Taxa in the Caspian Sea Waters of Iran

    Directory of Open Access Journals (Sweden)

    Siamak Bagheri

    2013-01-01

    Full Text Available A total of 61 zooplankton taxa were found in the southwestern Caspian Sea between 1996 and 2010. Thirteen of them were meroplankton taxa and forty-eight were holoplankton taxa. The occurrence of 14 freshwater taxa indicated the influence of the Anzali wetland and river inflows. The decrease in zooplankton taxa was detected since 1996-1997 and continued till 2010. Pleopis polyphemoides, the only one out of the nine recorded Cladocera species in 1996-1997, was found after 2001. Similarly, of the five Copepoda species recorded in 1996-1997, only one, Acartia tonsa, was found abundant during the 2001–2010 sampling period. It was striking that many species which were abundant in the Caspian Sea in 1996-1997 were not found after 2000. Many reasons could have contributed to the changes in the zooplankton composition of the southern Caspian Sea, notably the serious environmental degradation since the early 1990s. It is also possible that invasive species might play a role in wiping out some sensitive endemic species.

  2. spatial patterns of zooplankton distribution and abundance

    African Journals Online (AJOL)

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    production of fish species, invertebrates and availability of phytoplankton. Weekly monitoring for zooplankton abundance was conducted in .... chlorophyll-a pigment was extracted according to procedures recommended by ..... production of high density of bacteria and detrital matter which were effectively consumed by the ...

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

    African Journals Online (AJOL)

    The zooplankton of the River Kars was studied from May to October 2005 at five sampling stations. Thirty different zooplankton taxa were recorded, consisting of one copepod, four cladocera and twentyfive rotifers. The highest zooplankton densities were recorded in July and the lowest in October. Water temperature and ...

  4. Spatial patterns of zooplankton distribution and abundance in ...

    African Journals Online (AJOL)

    Spatial patterns and abundance of zooplankton in aquatic habitats are important determinants for production of fish species, invertebrates and availability of phytoplankton. Weekly monitoring for zooplankton abundance was conducted in Shirati Bay, Lake Victoria, to explore their spatial patterns in relation to phytoplankton, ...

  5. Seasonal variation of zooplankton abundance, composition and biomass in the Chabahar Bay, Oman Sea

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    Neda Fazeli

    2014-01-01

    Full Text Available Temporal and spatial variation of zooplankton abundance, composition and biomass were examined on the Chabahar Bay, Oman Sea. The Chabahar Bay, a subtropical and semi-enclosed bay, provides an ideal breeding ground for many fish and shellfish. Five stations were investigated along the Bay. This area is under the influence of the Indian Ocean seasonal monsoons. Zooplankton was collected with vertical plankton tows using 100 µm mesh nets. Copepods dominated the zooplankton community followed by larvacea, cladocera and chaetognatha. Fifteen taxa of zooplankton were identified. Oithona nana and Euterpina acutifrons were dominated in the whole year and Larvacea showed a bloom in Northeast Monsoon. A Two-way ANOVA indicated that there were differences in abundance and biomass between sampling periods and between stations were significant. The peak zooplankton abundance in NE Monsoon could be due to winter cooling, with entrainment of nutrients into the upper layer producing phytoplankton blooms. The decline of zooplankton abundance and biomass in South West Monsoon and post-monsoon could be explained by decrease in chlorophyll a concentrations. The present result showed the composition and distribution of zooplankton differed between the monsoon seasons, resulted from changes in hydrographic conditions.

  6. Changes in abundance and community structure of the zooplankton population during the 2008 mucilage event in the northeastern Marmara Sea

    OpenAIRE

    OKYAR, Melek İŞİNİBİLİR; ÜSTÜN, Funda; ORUN, Deniz Ayşe

    2015-01-01

    The composition and abundance of zooplankton and the corresponding environmental conditions were investigated during the 2008 mucilage event (April-December 2008) in the Marmara Sea. As a result, 46 zooplanktonic taxa were identified. Copepods and cladocerans were generally the most abundant groups. Mnemiopsis leidyi had a significant seasonality, and abundance was related to fluctuations in temperature and salinity. The most important species were Acartia clausi and Penilia avirostris, but t...

  7. Seasonal dynamics of zooplankton composition and abundance in ...

    African Journals Online (AJOL)

    Seasonal dynamics of zooplankton composition and abundance as influenced by physicochemical parameters of Thomas Dam were studied between January and October, 2016. Zooplankton and water samples for physicochemical parameters were collected and analyzed fortnightly between 8:00 – 10:00 am using ...

  8. 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...

  9. SUMMER ABUNDANCE AND ECOLOGY OF ZOOPLANKTON IN THE GULF STREAM.

    Science.gov (United States)

    Egan, W G; Conrad, J E

    1975-12-01

    We have described the results of laboratory analyses of 42 horizontal tows using a Clarke-Bumpus plankton sampler with a 100 µ emmesh net in the Gulf Stream. Classifications of 20 zooplankton taxa have been made for the 42 hauls. Calanoids dominate the hauls. It was found that the zooplankton population distribution and density varied considerably from haul to haul, but there was no consistent buildup or depletion of population with progress of the flow north in the Gulf Stream. These biological arguments reinforce previous conjectures that there is a geostrophically-balanced inflow of continental shelf and Labrador Sea water that gradually mixes with the Gulf Stream water mass. These inflows provide sources of zooplankton and phytoplankton to the Gulf Stream as it progresses northward. Also, an ecological analysis of the Gulf Stream indicates that the dry organic matter is over an order of magnitude below that which is theoretically possible.

  10. 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.

    During early southwest and northeast monsoon periods of 1967, zooplankton standing stocks and abundances were high all along the west coast of India. Swarms of zooplankton were common in the shelf areas resulting in a low diversity-high biomass...

  11. 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

  12. 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 ...

  13. Zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Madhu, N.V.

    A review on some important aspects of zooplankton community in the Mandovi and Zuari estuaries, Goa, India is presented. Both these estuaries have more or less similar zooplankton fauna with nearly 20 different taxonomic groups. Crustaceans...

  14. 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...

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

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    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.

  16. The composition, abundance and distribution of zooplankton of ...

    African Journals Online (AJOL)

    The zooplankton assemblage of River Niger at Onitsha stretch was investigated at five sampling stations from January 2008 to December 2009. Some physical and chemical parameters were studied. Among these are: transparency, total alkalinity, conductivity, total dissolved solid (TDS), total suspended solid (TSS), total ...

  17. 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

  18. 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...

  19. 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

  20. 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.

    are also due to Mr. S. Chakrabarthy and Mr. A. Chatterjee former and present country focal point respectively for Global Ballast Water Management Program in India. Logistic support provided by Dr. G. Joshi (BWMP) and Capt. Karkare (MPT) during the field... in the water quality parameters will directly affect the abundance and composition of zooplankton population. During the Port Biological Baseline Surveys of the Global Ballast Water Management Program (GloBallast), a GEF/UNDP/IMO initiative, we had...

  1. 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 ...

  2. Comparison of multifrequency acoustic and in situ measurements of zooplankton abundances in Knight Inlet, British Columbia

    Science.gov (United States)

    Trevorrow, Mark V.; Mackas, David L.; Benfield, Mark C.

    2005-06-01

    An investigation of midwater zooplankton aggregations in a coastal fjord was conducted in November 2002. This study focused on quantitative comparisons between a calibrated, three-frequency (38, 120, and 200 kHz) vessel-based echo-sounder, a multinet towed zooplankton sampler (BIONESS), and a high-resolution underwater camera (ZOOVIS). Daytime layers of euphausiids and amphipods near 70-90-m depth were observed in lower parts of the inlet, especially concentrated by tidal flows around a sill. Quantitative backscatter measurements of euphausiids and amphipods, combined with in situ size and abundance estimates, and using an assumed tilt-angle distribution, were in agreement with averaged fluid-cylinder scattering models produced by Stanton and Chu [ICES J. Mar. Sci. 57, 793-807, (2000)]. Acoustic measurements of physonect siphonophores in the upper inlet were found to have a strong 38-kHz scattering strength, in agreement with a damped bubble scattering model using a diameter of 0.4 mm. In relatively dense euphausiid layers, ZOOVIS abundance estimates were found to be a factor of 2 to 4 higher than the acoustic estimates, potentially due to deviations from assumed euphausiid orientation. Nocturnal near-surface euphausiid scattering exhibited a strong (15 dB) and rapid (seconds) sensitivity to vessel lights, interpreted as due to changing animal orientation. .

  3. Recovery dynamics of zooplankton following mouth-breaching in the ...

    African Journals Online (AJOL)

    Thirty-five taxa were identified, with the dominant copepod Pseudodiaptomus hessei accounting for 42% and 58% of the total abundance and biomass, respectively. Breaching resulted in a 98% loss of zooplankton biomass. While a ... Mouth state was primarily responsible for regulating zooplankton stock. However, the ...

  4. 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...

  5. 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

    To elucidate the possibilities of using zooplankton remains in the surface sediment to describe present-days community structure and population dynamics of zooplankton, fish abundance and temperature, we compared contemporary data sampled in the pelagial during summer with the sediment record fro...

  6. 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...

  7. Abundance of broad bacterial Taxa in the Sargasso Sea explained by environmental conditions but not water mass

    DEFF Research Database (Denmark)

    Sjöstedt, Johanna; Martiny, Jennifer Bellanca Hughes; Munk, Peter

    2014-01-01

    To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based...... of Synechococcus, Prochlorococcus, and picoalgae were determined by flow cytometry. Linear multiple-regression models determining the relative effects of eight environmental variables and of water mass explained 35 to 86% of the variation in abundance of the quantified taxa, even though only one to three variables...... the Sargasso Sea using only a few environmental parameters....

  8. 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...

  9. Impact of winter oceanographic conditions on zooplankton abundance in northern Adriatic with implications on Adriatic anchovy stock prognosis

    Science.gov (United States)

    Kraus, Romina; Supić, Nastjenjka; Lučić, Davor; Njire, Jakica

    2015-12-01

    Anchovy, Engraulis encrasicolus (L.), is commercially one of the most important Adriatic small pelagic fish. Despite the prevailing oligotrophication trend in the northern Adriatic (NA), the anchovy catch increased after 2000, coinciding with an increased number of the winter type A occurrences, when Po River waters are favoured to spread across the NA. Namely, winter type A is characterised by conditions resulting with Po River waters spreading across the NA along with salinity decrease. On the contrary, in winters of type B, salinity is high. We hypothesized in previous paper, based on correlation between circulation patterns and phytoplankton with anchovy catch, that excess feeding of anchovy in this winter pre-spawning period (February) can lead to increased amounts of the anchovy eggs two months later and subsequently to the total fish catch of the same year. In this paper, we investigate in more details and based on longer time series the relation between anchovy catch and winter circulation patterns of the NA. Additionally, we studied the association between anchovy catch and zooplankton, as anchovy is predominantly zooplanktivorous. We found that zooplankton abundances in winters of A type enhance and that ciliates play an important role in the NA anchovy food web and enrichment of the region with anchovy. Finally, the results of our investigation might in time represent the basics for a sustainable anchovy management in the Adriatic Sea as they enable the development of prediction models of the anchovy stock.

  10. Zooplankton Hydrodynamics

    DEFF Research Database (Denmark)

    Wadhwa, Navish

    Zooplankton are hugely abundant organisms found in all aquatic environments and form an important part of the marine ecosystems. Most zooplankton swim in order to find food and mates, and to avoid predators. In spite of its advantages, swimming comes with trade-offs, it costs energy and creates...... flow disturbances that may attract predators. The first part of this thesis attempts to quantify the trade-offs associated with the swimming behaviour of diverse zooplankton. We measured the swimming kinematics and flow fields around the 'jumping' copepod Acartia tonsa at various stages of its life...... cycle, and found qualitative differences in flow structures, energy expenditure, and swimming efficiency, between the early and later stages. The spatial decay rate of flow disturbances was faster in the later stages, suggesting that those may be less vulnerable to predation. Broadening the scope, we...

  11. A comparison of neustonic plastic and zooplankton abundance in southern California's coastal waters.

    Science.gov (United States)

    Moore, C J; Moore, S L; Weisberg, S B; Lattin, G L; Zellers, A F

    2002-10-01

    The density of neustonic plastic particles was compared to that of zooplankton in the coastal ocean near Long Beach, California. Two trawl surveys were conducted, one after an extended dry period when there was little land-based runoff, the second shortly after a storm when runoff was extensive. On each survey, neuston samples were collected at five sites along a transect parallel to shore using a manta trawl lined with 333 micro mesh. Average plastic density during the study was 8 pieces per cubic meter, though density after the storm was seven times that prior to the storm. The mass of plastics was also higher after the storm, though the storm effect on mass was less than it was for density, reflecting a smaller average size of plastic particles after the storm. The average mass of plastic was two and a half times greater than that of plankton, and even greater after the storm. The spatial pattern of the ratio also differed before and after a storm. Before the storm, greatest plastic to plankton ratios were observed at two stations closest to shore, whereas after the storm these had the lowest ratios.

  12. How do low-abundance taxa affect river biomonitoring? Exploring the response of different macroinvertebrate-based indices

    Directory of Open Access Journals (Sweden)

    Simone Guareschi

    2016-06-01

    Full Text Available The contribution of rare taxa to aquatic bioassessments remains a subject of debate, and generates contrasting positions among researchers. Very little is known about the effect of low-abundance taxa (LAT for calculating both single and multimetric macroinvertebrate-based indices, as well as the ecological status classification. In this study, we aimed to: i identify the aquatic macroinvertebrates that need special attention during index applications given their low abundance; ii analyse the effect of excluding LAT on single (IBMWP and IASPT and multimetric (STAR_ICMi biological indices; and iii investigate the influence of LAT on river ecological status assessments. To this end, two different river basins in SE Spain and N Italy with contrasting climatic conditions and river types were selected. Our results showed that almost all the taxa at the family level can act as low-abundance taxa. In particular, the LAT belonged mainly to orders Diptera, Trichoptera, Coleoptera, Gastropoda and Hemiptera. The IndVal analysis stressed Tabanidae, Cordulegasteridae and Hydroptilidae as the most characteristic low-abundance families in the Spanish data set, while Dryopidae and Athericidae were identified mostly in N Italy. Excluding LAT affected the studied index values and the resulting bioassessment classification, except for the IASPT index. Loss of the entire LAT pool reduced the ecological status for 78% of the samples for the IBMWP index. Changing took place in 41% of the samples when considering the STAR_ICM index. Relevant changes were detected even when considering loss of 50% of the LAT, especially with the IBMWP index. Similar values and patterns were obtained in each considered quality class and river type. Our results provide useful information about controversial taxa and stress the significance of LAT in river biomonitoring. Excluding LAT is discouraged, although different responses according to the considered index were detected. The IBMWP

  13. 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

  14. Effect of leaf type and pesticide exposure on abundance of bacterial taxa in mosquito larval habitats.

    Directory of Open Access Journals (Sweden)

    Ephantus J Muturi

    Full Text Available Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations of four pesticides with different modes of action on the target organisms; permethrin, malathion, atrazine and glyphosate. We tested the hypotheses that leaf species support different quantities of major taxonomic groups of bacteria and that exposure to pesticides at environmentally relevant concentrations alters bacterial abundance and community structure in mosquito larval habitats. We found support for both hypotheses suggesting that leaf litter identity and chemical contamination may alter the quality and quantity of mosquito food base (microbial communities in larval habitats. The effect of pesticides on microbial communities varied significantly among leaf types, suggesting that the impact of pesticides on natural microbial communities may be highly complex and difficult to predict. Collectively, these findings demonstrate the potential for detritus composition within mosquito larval habitats and exposure to pesticides to influence the quality of mosquito larval habitats.

  15. 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

  16. 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...

  17. Future marine zooplankton research - a perspective

    DEFF Research Database (Denmark)

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

    2001-01-01

    During the Second Marine Zooplankton Colloquium (MZC2) 3 issues were added to those developed 11 yr ago during the First Marine Zooplankton Colloquium (MZC1). First, we focused on hot spots, i.e., locations where zooplankton occur in higher than regular abundance and/or operate at higher rates, W...

  18. 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

  19. Deep-water zooplankton in the Mediterranean Sea: Results from a continuous, synchronous sampling over different regions using sediment traps

    Science.gov (United States)

    Danovaro, R.; Carugati, L.; Boldrin, A.; Calafat, A.; Canals, M.; Fabres, J.; Finlay, K.; Heussner, S.; Miserocchi, S.; Sanchez-Vidal, A.

    2017-08-01

    Information on the dynamics of deep-sea biota is extremely scant particularly for long-term time series on deep-sea zooplankton. Here, we present the results of a deep-sea zooplankton investigation over one annual cycle based on samples from sediment trap moorings in three sub-basins along the Mediterranean Sea. Deep-sea zooplankton assemblages were dominated by copepods, as in shallow waters, only in the Adriatic Sea (>60% of total abundance), but not in the deep Ionian Sea, where ostracods represented >80%, neither in the deep Alboran Sea, where polychaetes were >70%. We found that deep-sea zooplankton assemblages: i) are subjected to changes in their abundance and structure over time, ii) are characterized by different dominant taxa in different basins, and iii) display clear taxonomic segregation between shallow and near-bottom waters. Zooplankton biodiversity decreases with increasing water depth, but the equitability increases. We suggest here that variations of zooplankton abundance and assemblage structure are likely influenced by the trophic condition characterizing the basins. Our findings provide new insights on this largely unknown component of the deep ocean, and suggest that changes in the export of organic matter from the photic zone, such as those expected as a consequence of global change, can significantly influence zooplankton assemblages in the largest biome on Earth.

  20. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses

    Energy Technology Data Exchange (ETDEWEB)

    1990-02-07

    The goal of the Fall Removal Experiment 1987 was to determine the processes affecting the dependent and fate of low salinity coastal water and of biological material therein during fall when winds are mainly south-to westward. Five zooplankton taxa, Acartia tonsa, (A. tonsa) Paracalanus species (sp), Temora turbinata (T. turbinata), Oncaea sp, and Sagitta enflata were examined. Data on the distribution of all five taxa were presented, and distribution over time was also studied. The abundance of A. tonsa decreased tenfold over the 13 day sampling period, Paracalanus varied twofold and T. Turbinata showed little variability. The A. tonsa decrease was postulated to result from food abundance or predation, although the possible role of size distribution, water displacement and chlorophyll distribution will be examined in the future. A possible role of turbulence in zooplankton abundance is being examined. 8 refs., 5 figs.

  1. Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes.

    Science.gov (United States)

    Jones, Natalie T; Gilbert, Benjamin

    2016-03-01

    In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice-free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 h) and two temperatures (8 and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. Copepod hatchling abundances peaked at mid-latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid-latitudes (~56 °N) in the shorter photoperiod treatment. Our results demonstrate that hatching cues

  2. 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.

  3. Temporal Variability of Zooplankton (2000-2013) in the Levantine Sea: Significant Changes Associated to the 2005-2010 EMT-like Event?

    Science.gov (United States)

    Ouba, Anthony; Abboud-Abi Saab, Marie; Stemmann, Lars

    2016-01-01

    In this study, we investigated, for the first time, the potential impact of environmental changes on zooplankton abundance over a fourteen year period (2000-2013) at an offshore station in the Eastern Mediterranean Sea (the Levantine basin, offshore Lebanon). Samples were collected monthly and analyzed using the semi-automated system ZooScan. Salinity, temperature and phytoplankton abundance (nano and microphytoplankton) were also measured. Results show no significant temporal trend in sea surface temperature over the years. Between 2005-2010, salinity in the upper layer (0-80 m) of the Levantine basin increased (~0.3°C). During this 5 year period, total zooplankton abundance significantly increased. These modifications were concomitant to the activation of Aegean Sea as a source of dense water formation as part of the "Eastern Mediterranean Transient-like" event. The results of the present study suggested that zooplankton benefited from enhanced phytoplankton production during the mixing years of the event. Changes in the phenology of some taxa were observed accordingly with a predominantly advanced peak of zooplankton abundance. In conclusion, long-term changes in zooplankton abundance were related to the Levantine thermohaline circulation rather than sea surface warming. Sampling must be maintained to assess the impact of long-term climate change on zooplankton communities.

  4. Temporal Variability of Zooplankton (2000-2013 in the Levantine Sea: Significant Changes Associated to the 2005-2010 EMT-like Event?

    Directory of Open Access Journals (Sweden)

    Anthony Ouba

    Full Text Available In this study, we investigated, for the first time, the potential impact of environmental changes on zooplankton abundance over a fourteen year period (2000-2013 at an offshore station in the Eastern Mediterranean Sea (the Levantine basin, offshore Lebanon. Samples were collected monthly and analyzed using the semi-automated system ZooScan. Salinity, temperature and phytoplankton abundance (nano and microphytoplankton were also measured. Results show no significant temporal trend in sea surface temperature over the years. Between 2005-2010, salinity in the upper layer (0-80 m of the Levantine basin increased (~0.3°C. During this 5 year period, total zooplankton abundance significantly increased. These modifications were concomitant to the activation of Aegean Sea as a source of dense water formation as part of the "Eastern Mediterranean Transient-like" event. The results of the present study suggested that zooplankton benefited from enhanced phytoplankton production during the mixing years of the event. Changes in the phenology of some taxa were observed accordingly with a predominantly advanced peak of zooplankton abundance. In conclusion, long-term changes in zooplankton abundance were related to the Levantine thermohaline circulation rather than sea surface warming. Sampling must be maintained to assess the impact of long-term climate change on zooplankton communities.

  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. 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

  7. 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.

  8. 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...... predators such as seabirds and fish. The acoustic survey showed the highest density of polar cod Boreogadus saida in the upper 50 m on the western part of the Greenland Shelf. A particularly high biomass of both zooplankton and polar cod was found in the central part of the basin in association with a local...

  9. 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.

  10. 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 ...

  11. Clearance rates of jellyfish and their potential predation impact on zooplankton and fish larvae in a neritic ecosystem (Limfjorden, Denmark)

    DEFF Research Database (Denmark)

    Hansson, L. J.; Moeslund, O.; Kiørboe, Thomas

    2005-01-01

    comparatively low. These data were used to assess the impact of jellyfish predation upon zooplankton and fish larvae in Limfjorden, Denmark. Repeated sampling of zooplankton, fish larvae and medusae was undertaken during the first half of 2003. Nine taxa of hydromedusae and 4 taxa of scyphomedusae were...... identified. Abundance estimates were combined with estimated clearance rates of individual medusae to calculate potential jellyfish-induced mortality on prey in Limfjorden. Copepoda was used as a model prey group to estimate the collective predation impact by all medusae. Medusa species with unknown...... clearance potential were given assumed clearance rate values, but the collective predation potential by these species was evaluated to be small. Hydromedusae dominated numerically and had their highest potential clearance impact in spring, but overall jellyfish clearance potential on copepods was low during...

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

    African Journals Online (AJOL)

    Results show that the state of the lagoon is a hyper-eutrophic environment, characterized by high levels of chlorophyll-a and nitrogen. Pollution-tolerant zooplankton such as Brachionus was the dominant species in the lagoon. A total of 61 taxa were recorded, including 35 rotifers, 13 copepods, 5 ostracods, 6 protozoa and ...

  13. 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...

  14. 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

  15. Metagenomic insights into zooplankton-associated bacterial communities

    DEFF Research Database (Denmark)

    De Corte, Daniele; Srivastava, Abhishek; Koski, Marja

    2018-01-01

    ocean. The zooplankton-associated bacterial community is able to colonize the zooplankton's internal and external surfaces by using a large set of adhesion mechanisms and to metabolize complex organic compounds released or exuded by the zooplankton such as chitin, taurine and other complex molecules....... Moreover, the high number of genes involved in iron and phosphorus metabolisms in the zooplankton-associated microbiome suggests that this zooplankton-associated bacterial community mediates specific biogeochemical processes (through the proliferation of specific taxa) that are generally underrepresented......, we assessed the phylogenetic composition and metabolic potential of microbial communities associated with crustacean zooplankton species collected in the North Atlantic. Using Illumina sequencing of the 16S rRNA gene we found significant differences between the microbial communities associated...

  16. Avoidance of strobe lights by zooplankton

    Science.gov (United States)

    Hamel, Martin J.; Richards, Nathan S.; Brown, Michael L.; Chipps, Steven R.

    2010-01-01

    Underwater strobe lights can influence the behavior and distribution of fishes and are increasingly used as a technique to divert fish away from water intake structures on dams. However, few studies examine how strobe lights may affect organisms other than targeted species. To gain insight on strobe lighting effects on nontarget invertebrates, we investigated whether underwater strobe lights influence zooplankton distributions and abundance in Lake Oahe, South Dakota. Zooplankton were collected using vertical tows at 3 discrete distances from an underwater strobe light to quantify the influence of light intensity on zooplankton density. Samples were collected from 3 different depth ranges (0–10 m, 10–20 m and 20–30 m) at strobe light. Copepods represented 67.2% and Daphnia spp. represented 23.3% of all zooplankton sampled from 17 August to 15 September 2004. Night time zooplankton densities significantly decreased in surface waters when strobe lights were activated. Copepods exhibited the greatest avoidance patterns, while Daphnia avoidance varied throughout sampling depths. These results indicate that zooplankton display negative phototaxic behavior to strobe lights and that researchers must be cognizant of potential effects to the ecosystem such as altering predator–prey interactions or affecting zooplankton distribution and growth.

  17. Intra-annual seasonal variability of surface zooplankton distribution patterns along a 110°E transect of the Southern Ocean in the austral summer of 2011/12

    Science.gov (United States)

    Takahashi, Kunio T.; Hosie, Graham W.; Odate, Tsuneo

    2017-06-01

    Seasonal cycles can provide insight into the interactions between zooplankton and the environment. However, few intra-annual seasonal studies have been undertaken in the Southern Ocean. We investigated the composition, distribution, and abundance of micro- and meso-zooplankton along the 110°E meridian with three transects in December 2011, January and March 2012 using a Continuous Plankton Recorder. High zooplankton abundance was recorded in the Polar Frontal Zone (PFZ) and the Antarctic Zone (AZ) in both day and night at all transects with 179.0-300.9 ind. m-3. The small copepods Oithona similis, Ctenocalanus citer, and copepodites indet (copepod indeterminable) were dominant in the PFZ and AZ communities. Total zooplankton abundance was comparatively consistent among transects. Nighttime abundance levels remained high in the AZ in March with high abundance of copepodites indet. This seasonal fluctuation appeared to be influenced by recruitment of new populations. Most core species/taxa, except for O. similis, C. citer, and foraminiferans in the AZ area in early January, exhibited a diel decrease in abundance. A multi-ship intra-annual seasonal survey will help detect their various regional and/or seasonal distribution patterns, and the impacts of environmental change on Southern Ocean pelagic ecosystems.

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

    African Journals Online (AJOL)

    Zooplankton form an important trophic link between phytoplankton and fish in the aquatic food chain. Investigation was carried out on the zooplankton community of Ojirami, Reservoir, Nigeria, to document the composition, abundance and distribution and their interactions with the physico-chemical conditions. Surface water ...

  19. Seasonal features of zooplankton in Petrozavodskaya Bay of Lake Onega

    Directory of Open Access Journals (Sweden)

    Syarky Maria

    2014-11-01

    Full Text Available Phenological phases or seasons of the zooplankton were determined by the method of discriminatory analysis in Petrozavodsk bay of Lake Onega. On the basis of the data on the zooplankton abundance and the biomass of the main taxonomic groups, received from 1988 to 2010, four seasonal conditions of the community, their timing and duration were determined. On an average, summer period for zooplankton in Petrozavodskaya bay lasts 66 days, it is 24 days longer than in the central area of the lake. The relationship between zooplankton phenology and hydrodynamic and thermal conditions are considered

  20. 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

    zone. However, in most lakes the abundance of Ceriodaphnia was higher in the sediment than in the water, which may be attributed to the overall preference by this genus for the littoral habitat. Using contemporary data from 27 Danish lakes sampled fortnightly during summer for 10 years, we found...

  1. 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

  2. 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.

  3. Zooplankton distribution in the polluted environment around Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Abidi, S.A.H.

    Zooplankton distribution, abundance and composition with reference to polluted environments off Bombay was estimated. This study was taken up along three transects viz. Versova, Mahim and Thana covering eleven stations around Bombay during 1980...

  4. 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...

  5. zooplankton of the Sundays

    African Journals Online (AJOL)

    Euryhaline zooplankton of the Sundays estuary and notes on trophic relationships. T. Wooldridge and C. Bailey. Department of Zoology, University of Port Elizabeth, Port Elizabeth. ~lJNIViIi8tT~. ~BRARy'/. The euryhaline component of the zooplankton in the Sundays River estuary was sampled monthly at 10 stations from ...

  6. 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...

  7. Gelatinous zooplankton in the Belgian part of the North Sea and the adjacent Schelde estuary: Spatio-temporal distribution patterns and population dynamics

    Science.gov (United States)

    Vansteenbrugge, Lies; Van Regenmortel, Tina; De Troch, Marleen; Vincx, Magda; Hostens, Kris

    2015-03-01

    Many ocean ecosystems are thought to be heading towards a dominance of gelatinous organisms. However, gelatinous zooplankton has been largely understudied and the absence of quantitative long-term data for the studied area impedes drawing conclusions on potential increasing densities. This study gives a comprehensive overview of the spatio-temporal distribution patterns of gelatinous zooplankton in terms of diversity and density in the Belgian part of the North Sea and the adjacent Schelde estuary, based on monthly and seasonal samples between March 2011 and February 2012. Three Scyphozoa, three Ctenophora and 27 Hydrozoa taxa were identified, including three non-indigenous species: Mnemiopsis leidyi, Nemopsis bachei and Lovenella assimilis. In general, one gelatinous zooplankton assemblage was found across locations and seasons. Average gelatinous zooplankton densities reached up to 18 ind·m-3 near the coast, gradually declining towards the open sea. In the brackish Schelde estuary, average densities remained below 3 ind·m-3. Highest gelatinous zooplankton densities were recorded in summer and autumn. Overall, hydromedusae were the most important group both in terms of diversity and density. The ctenophore Pleurobrachia pileus and the hydromedusa Clytia sp. were present in every season and at every location. Gelatinous zooplankton densities never outnumbered the non-gelatinous zooplankton densities recorded from the WP3 samples. The spatial and temporal distribution patterns seemed to be mainly driven by temperature (season) and salinity (location). Other environmental parameters including (larger) non-gelatinous zooplankton densities (as an important food source) were not retained in the most parsimonious DistLM model.In terms of population dynamics, Beroe sp. seemed to follow the three reproductive cycles of its prey P. pileus and the presence of M. leidyi, which were abundant in a broad size spectrum in summer and autumn. In general, gelatinous zooplankton

  8. 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...

  9. Identification and genome reconstruction of abundant distinct taxa in microbiomes from one thermophilic and three mesophilic production-scale biogas plants.

    Science.gov (United States)

    Stolze, Yvonne; Bremges, Andreas; Rumming, Madis; Henke, Christian; Maus, Irena; Pühler, Alfred; Sczyrba, Alexander; Schlüter, Andreas

    2016-01-01

    Biofuel production from conversion of biomass is indispensable in the portfolio of renewable energies. Complex microbial communities are involved in the anaerobic digestion process of plant material, agricultural residual products and food wastes. Analysis of the genetic potential and microbiology of communities degrading biomass to biofuels is considered to be the key to develop process optimisation strategies. Hence, due to the still incomplete taxonomic and functional characterisation of corresponding communities, new and unknown species are of special interest. Three mesophilic and one thermophilic production-scale biogas plants (BGPs) were taxonomically profiled using high-throughput 16S rRNA gene amplicon sequencing. All BGPs shared a core microbiome with the thermophilic BGP featuring the lowest diversity. However, the phyla Cloacimonetes and Spirochaetes were unique to BGPs 2 and 3, Fusobacteria were only found in BGP3 and members of the phylum Thermotogae were present only in the thermophilic BGP4. Taxonomic analyses revealed that these distinctive taxa mostly represent so far unknown species. The only exception is the dominant Thermotogae OTU featuring 16S rRNA gene sequence identity to Defluviitoga tunisiensis L3, a sequenced and characterised strain. To further investigate the genetic potential of the biogas communities, corresponding metagenomes were sequenced in a deepness of 347.5 Gbp in total. A combined assembly comprised 80.3 % of all reads and resulted in the prediction of 1.59 million genes on assembled contigs. Genome binning yielded genome bins comprising the prevalent distinctive phyla Cloacimonetes, Spirochaetes, Fusobacteria and Thermotogae. Comparative genome analyses between the most dominant Thermotogae bin and the very closely related Defluviitoga tunisiensis L3 genome originating from the same BGP revealed high genetic similarity. This finding confirmed applicability and reliability of the binning approach. The four highly covered

  10. Drake Passage-Antarctic Peninsula Ecosystem Research: Spring and Fall Zooplankton and Seabird Assemblages

    Science.gov (United States)

    Loeb, V. J.; Chereskin, T. K.; Santora, J. A.

    2016-02-01

    Acoustic Doppler Current Profiler (ADCP) records from multiple "L.M. Gould" supply transits of Drake Passage from 1999 to present demonstrate spatial and temporal (diel, seasonal, annual and longer term) variability in acoustics backscattering. Acoustics backscattering strength in the upper water column corresponds to zooplankton and nekton biomass that relates to seabird and mammal distribution and abundance. Recent results indicate that interannual variability in backscattering strength is correlated to climate indices. The interpretation of these ecological changes is severely limited because the sound scatterers previously had not been identified and linkages to upper trophic level predators are unknown. Net-tows, depth-referenced underwater videography and seabird/mammal visual surveys during spring 2014 and fall 2015 transits provided information on the taxonomic-size composition, distribution, aggregation and behavioral patterns of dominant ADCP backscattering organisms and relate these to higher level predator populations. The distribution and composition of zooplankton species and seabird assemblages conformed to four biogeographic regions. Areas of elevated secondary productivity coincided with increased ADCP target strength with highest concentrations off Patagonia and Antarctic Peninsula and secondary peaks around the Polar Front. Small sized zooplankton taxa dominated north of the Polar Front while larger taxa dominated to the south. Regionally important prey items likely are: copepods, amphipods, small euphausiids and fish (Patagonia); copepods, myctophids, shelled pteropods and squid (Polar Front); large euphausiids (Antarctic Peninsula). This study demonstrates that biological observations during "L.M. Gould" supply transits greatly augment the value of routinely collected ADCP and XBT data and provide basic information relevant to the impacts of climate change in this rapidly warming portion of the Southern Ocean

  11. 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 ...

  12. Material properties of zooplankton and nekton from the California current

    Science.gov (United States)

    Becker, Kaylyn

    This study measured the material properties of zooplankton, Pacific hake (Merluccius productus), Humboldt squid (Dosidicus gigas), and two species of myctophids (Symbolophorus californiensis and Diaphus theta) collected from the California Current ecosystem. The density contrast (g) was measured for euphausiids, decapods (Sergestes similis), amphipods (Primno macropa, Phronima sp., and Hyperiid spp.), siphonophore bracts, chaetognaths, larval fish, crab megalopae, larval squid, and medusae. Morphometric data (length, width, and height) were collected for these taxa. Density contrasts varied within and between zooplankton taxa. The mean and standard deviation for euphausiid density contrast were 1.059 +/- 0.009. Relationships between zooplankton density contrast and morphometric measurements, geographic location, and environmental conditions were investigated. Site had a significant effect on euphausiid density contrast. Density contrasts of euphausiids collected in the same geographic area approximately 4-10 days apart were significantly higher (p tentacle, braincase, eyes, pen, and beak. The density contrasts varied within and between fish taxa, as well as among squid body parts. Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast (h) was measured for Pacific hake flesh, myctophid flesh, Humboldt squid mantle, and Humboldt squid braincase. Sound speed varied within and between nekton taxa. The material properties reported in this study can be used to improve target strength estimates from acoustic scattering models which would increase the accuracy of biomass estimates from acoustic surveys for these zooplankton and nekton.

  13. 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 ...

  14. Composição, abundância e distribuição espacial do zooplâncton no complexo estuarino de Paranaguá durante o inverno de 1993 e o verão de 1994 Zooplankton composition, abundance and spatial distribution in the estuarine complex of Paranaguá during winter 1993 and summer 1994

    Directory of Open Access Journals (Sweden)

    Rubens M. Lopes

    1998-01-01

    copepod in oligohaline stretches with salinities below 15. Estuarine marine species such as Acartia tonsa, Oithona hebes and Oithona oswaldocruzi reached high densities in salinities ranging from 17 to 25. Other abundant estuarine marine species including Acartia lilljeborgi and Pseudodiaptomus acutus occurred in a broader salinity range. Marine euryhaline copepods were found in salinities as low as 15, but were usually more abundant in areas under the influence of coastal waters. Several marine stenohaline species associated with the warm waters of the Brazil Current were recorded in the euhaline areas. Other important zooplanktonic groups in this estuarine complex were tintinnids, appendicularians, cladocerans and meroplanktonic larvae of polychaetes and decapods. Density maxima (up to 82400 org.m-³ were found in the intermediate stretches - in salinities varying from 15 to 30 - corresponding approximately to the distributional pattern of phytoplankton biomass.

  15. 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

  16. 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

  17. Biotic and abiotic factors influencing zooplankton vertical distribution in Lake Huron

    Science.gov (United States)

    Nowicki, Carly J.; Bunnell, David B.; Armenio, Patricia M.; Warner, David M.; Vanderploeg, Henry A.; Cavaletto, Joann F.; Mayer, Christine M.; Adams, Jean V.

    2017-01-01

    The vertical distribution of zooplankton can have substantial influence on trophic structure in freshwater systems, particularly by determining spatial overlap for predator/prey dynamics and influencing energy transfer. The zooplankton community in some of the Laurentian Great Lakes has undergone changes in composition and declines in total biomass, especially after 2003. Mechanisms underlying these zooplankton changes remain poorly understood, in part, because few studies have described their vertical distributions during daytime and nighttime conditions or evaluated the extent to which predation, resources, or environmental conditions could explain their distribution patterns. Within multiple 24-h periods during July through October 2012 in Lake Huron, we conducted daytime and nighttime sampling of zooplankton, and measured food (chlorophyll-a), temperature, light (Secchi disk depth), and planktivory (biomass of Bythotrephes longimanus and Mysis diluviana). We used linear mixed models to determine whether the densities for 22 zooplankton taxa varied between day and night in the epi-, meta-, and hypolimnion. For eight taxa, higher epilimnetic densities were observed at night than during the day; general linear models revealed these patterns were best explained by Mysis diluviana (four taxa), Secchi disk depth (three taxa), epilimnetic water temperature (three taxa), chlorophyll (one taxon), and biomass of Bythotrephes longimanus (one taxon). By investigating the potential effects of both biotic and abiotic variables on the vertical distribution of crustacean zooplankton and rotifers, we provide descriptions of the Lake Huron zooplankton community and discuss how future changes in food web dynamics or climate change may alter zooplankton distribution in freshwater environments.

  18. 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

  19. 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.

  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. A checklist for the zooplankton of the Middle Xingu - an Amazon River system.

    Science.gov (United States)

    Brito, S A C; Camargo, M; Melo, N F A C; Estupiñan, R A

    2015-08-01

    A zooplankton checklist is presented for the Middle Xingu River, based on surveys conducted at four sites in the main channel and two fluvial lakes. A total of 175 taxa are listed, including 141 rotifers, 20 cladocerans, and five copepods. Rapids presented the greatest species richness, with up to 124 taxa, while Ilha Grande lake had 70 taxa, the lowest number. Non-planktonic benthic larvae were recorded frequently in the samples.

  2. 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.

  3. 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).

  4. 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.

  5. 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...

  6. Zooplankton - Study methods, importance and significant observations

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.

    The intent of this section is to review briefly current knowledge of the structure and dynamics of the zooplankton and its ecology. Zooplankton are mysids of animal organisms that drift with currents. In an aquatic ecosystem zooplankton form...

  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. 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

  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. PCR-Based Assessment of Freshwater Zooplankton Feeding on Edible and "Inedible" Prey In Situ.

    Science.gov (United States)

    Nejstgaard, J. C.; Belyaeva, M.; Van den Wyngaert, S.; Berger, S. A.; Grossart, H. P.; Kasprzak, P.

    2016-02-01

    Microbiota in pelagic ecosystems can affect zooplankton nutrition in several ways that are not readily assessable in situ, using classical approaches. In contrast to classical food web models identifying phytoplankton as the dominant food source for crustacean zooplankton, recent findings increasingly suggest that zooplankton may derive a significant part of the diet from a wide variety of taxa including ciliates, aquatic fungi, bacteria and small metazoan zooplankton (e.g. rotifers), in both marine and freshwaters. Direct quantification of soft-bodied and non-pigmented prey in zooplankton guts as well as symbionts and parasites on the prey and zooplankton itself has so far been impeded by the lack of appropriate methodology. We aim to establish molecular approaches to quantify these yet-understudied interactions in lake food webs. As a first step we have validated the qPCR detection method in laboratory experiments with cladoceran, calanoid and cyclopoid predators and algal prey species (Cryptomonas sp.). We plan to apply the method to study the dietary contribution of aquatic fungi - chytrids, which are parasites on inedible phytoplankton species, thus aiming to provide insights into the Mycoloop - energy transfer from inedible phytoplankton to zooplankton via fungal parasites. The quantitative PCR method, when validated for key zooplankton species and specific prey or parasite groups, has a potential for a broad range of applications in food web research.

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

    African Journals Online (AJOL)

    species abundance are affected by the flood coming, when the upstream station is different from the two other at the biological level. Conclusion: The zooplankton ... The Lake Hlan currently continues to be a reference ecosystem in ecological status evaluation in Benin republic, since its localization has low accessibility.

  14. 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 ...

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

    African Journals Online (AJOL)

    This study compares the meso-zooplankton composition within the channel on both flood and ebb tides, providing a preliminary understanding of the role of the Mfolozi channel in the migration and recruitment of organisms. Abundance was higher on ebb tides, while species richness was higher on flood tides. A total of 53 ...

  16. 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

  17. 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.

  18. DINAMIKA SPASIAL DAN TEMPORAL STRUKTUR KOMUNITAS ZOOPLANKTON DI TELUK JAKARTA

    Directory of Open Access Journals (Sweden)

    Masykhur Abdul Kadir

    2015-12-01

    Full Text Available Study of spatial and temporal dynamics of zooplankton community structure in the Jakarta Bay. The purpose are analyzing the abundance, distribution, diversity, and dominance index with indicators of water quality spatial and temporal waters of Jakarta Bay. The research was conducted from July-October 2013. Sampling was done four times (July, August, September, and October. The water quality was analysed by Laboratory Productivity and Water Environment at Department of Resources Management, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University. Zooplankton were analyzed using the method of enumeration (census SRC, in Micro Biology Laboratory Faculty. Based on the distribution patterns were its indicates that the landward dissolved oxygen (DO is increasingly high, especially in August, September, and October, and increase the abundance of zooplankton as much as 1.3106 Ind/m3. DO with a high spatial concentration value reaches the range of 6.2-14.5 mg/L in Muara Marunda (Station 10, and increase the abundance of zooplankton as much as 5.1106 Ind/m3, with a majority composition of crustacea. Results of classification was diversity moderate, stable uniformity, and high dominance index.

  19. 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.

  20. 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.

  1. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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

    water, even during periods where the predation pressure was presumably high (during the recruitment of 0+ fish fry). Zooplankton abundance in open water and among vegetation exhibited low values in July and peaked in August. Bosmina and Ceriodaphnia dominated the zooplankton community in the littoral...

  4. 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...

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

    Science.gov (United States)

    Neumann-Leitão, Sigrid; Melo, Pedro A M C; Schwamborn, Ralf; Diaz, Xiomara F G; Figueiredo, Lucas G P; Silva, Andrea P; Campelo, Renata P S; de Melo Júnior, Mauro; Melo, Nuno F A C; Costa, Alejandro E S F; Araújo, Moacyr; Veleda, Dóris R A; Moura, Rodrigo L; Thompson, Fabiano

    2018-01-01

    At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km 2 ) 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

  6. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Stable isotope and signature fatty acid analyses suggest reef manta rays feed on demersal zooplankton.

    Directory of Open Access Journals (Sweden)

    Lydie I E Couturier

    Full Text Available Assessing the trophic role and interaction of an animal is key to understanding its general ecology and dynamics. Conventional techniques used to elucidate diet, such as stomach content analysis, are not suitable for large threatened marine species. Non-lethal sampling combined with biochemical methods provides a practical alternative for investigating the feeding ecology of these species. Stable isotope and signature fatty acid analyses of muscle tissue were used for the first time to examine assimilated diet of the reef manta ray Manta alfredi, and were compared with different zooplankton functional groups (i.e. near-surface zooplankton collected during manta ray feeding events and non-feeding periods, epipelagic zooplankton, demersal zooplankton and several different zooplankton taxa. Stable isotope δ(15N values confirmed that the reef manta ray is a secondary consumer. This species had relatively high levels of docosahexaenoic acid (DHA indicating a flagellate-based food source in the diet, which likely reflects feeding on DHA-rich near-surface and epipelagic zooplankton. However, high levels of ω6 polyunsaturated fatty acids and slightly enriched δ(13C values in reef manta ray tissue suggest that they do not feed solely on pelagic zooplankton, but rather obtain part of their diet from another origin. The closest match was with demersal zooplankton, suggesting it is an important component of the reef manta ray diet. The ability to feed on demersal zooplankton is likely linked to the horizontal and vertical movement patterns of this giant planktivore. These new insights into the habitat use and feeding ecology of the reef manta ray will assist in the effective evaluation of its conservation needs.

  9. Stable Isotope and Signature Fatty Acid Analyses Suggest Reef Manta Rays Feed on Demersal Zooplankton

    Science.gov (United States)

    Couturier, Lydie I. E.; Rohner, Christoph A.; Richardson, Anthony J.; Marshall, Andrea D.; Jaine, Fabrice R. A.; Bennett, Michael B.; Townsend, Kathy A.; Weeks, Scarla J.; Nichols, Peter D.

    2013-01-01

    Assessing the trophic role and interaction of an animal is key to understanding its general ecology and dynamics. Conventional techniques used to elucidate diet, such as stomach content analysis, are not suitable for large threatened marine species. Non-lethal sampling combined with biochemical methods provides a practical alternative for investigating the feeding ecology of these species. Stable isotope and signature fatty acid analyses of muscle tissue were used for the first time to examine assimilated diet of the reef manta ray Manta alfredi, and were compared with different zooplankton functional groups (i.e. near-surface zooplankton collected during manta ray feeding events and non-feeding periods, epipelagic zooplankton, demersal zooplankton and several different zooplankton taxa). Stable isotope δ15N values confirmed that the reef manta ray is a secondary consumer. This species had relatively high levels of docosahexaenoic acid (DHA) indicating a flagellate-based food source in the diet, which likely reflects feeding on DHA-rich near-surface and epipelagic zooplankton. However, high levels of ω6 polyunsaturated fatty acids and slightly enriched δ13C values in reef manta ray tissue suggest that they do not feed solely on pelagic zooplankton, but rather obtain part of their diet from another origin. The closest match was with demersal zooplankton, suggesting it is an important component of the reef manta ray diet. The ability to feed on demersal zooplankton is likely linked to the horizontal and vertical movement patterns of this giant planktivore. These new insights into the habitat use and feeding ecology of the reef manta ray will assist in the effective evaluation of its conservation needs. PMID:24167562

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

    Directory of Open Access Journals (Sweden)

    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.

  11. prepare_taxa_charts

    Science.gov (United States)

    Lakhujani, Vijay; Badapanda, Chandan

    2017-06-01

    QIIME (Quantitative Insights Into Microbial Ecology) is one of the most popular open-source bioinformatics suite for performing metagenome, 16S rRNA amplicon and Internal Transcribed Spacer (ITS) data analysis. Although, it is very comprehensive and powerful tool, it lacks a method to provide publication ready taxonomic pie charts. The script plot_taxa_summary . py bundled with QIIME generate a html file and a folder containing taxonomic pie chart and legend as separate images. The images have randomly generated alphanumeric names. Therefore, it is difficult to associate the pie chart with the legend and the corresponding sample identifier. Even if the option to have the legend within the html file is selected while executing plot_taxa_summary . py , it is very tedious to crop a complete image (having both the pie chart and the legend) due to unequal image sizes. It requires a lot of time to manually prepare the pie charts for multiple samples for publication purpose. Moreover, there are chances of error while identifying the pie chart and legend pair due to random alphanumeric names of the images. To bypass all these bottlenecks and make this process efficient, we have developed a python based program, prepare_taxa_charts . py , to automate the renaming, cropping and merging of taxonomic pie chart and corresponding legend image into a single, good quality publication ready image. This program not only augments the functionality of plot_taxa_summary . py but is also very fast in terms of CPU time and user friendly.

  12. 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.

  13. 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.

    of zooplankton biomass were associated with high tide. Distribution of various groups of zooplankton indicated variability in their quantitative and qualitative representation. Most common groups like copepods, decapods and chaetognaths followed a pattern similar...

  14. Zooplankton community of Keibul Lamjao National Park (KLNP) Manipur, India in relation to the physico-chemical variables of the water

    Science.gov (United States)

    Sharma, Aribam Satishchandra; Gupta, Susmita; Singh, N. Rajmuhon

    2017-05-01

    Keibul Lamjao National Park (KLNP), a floating park in Loktak Lake, Manipur (India) was studied from Winter (WIN) to Post Monsoon (POM) for its zooplankton composition and some selected water parameters. The resultant data were subjected to multivariate techniques-Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). Analyses of water parameters with PCA revealed that the first PC axis (PC1) accounts for maximum variance in the seasonal data, explaining a variability of 91%. The PCA revealed that the seasonal variability in water parameters was due to the wet and dry cycle of seasons and the stations were distinguished on the basis of transparency and turbidity. Zooplankton abundance was dominated by copepods followed by cladocerans. Temporally, abundance of copepods reached a maximum during Post-monsoon (POM) (3 880 ind./L). Spatially, S6 was found to be most abundant of the other stations in zooplankton. Copepodites and nauplii larvae were the major components of zooplankton. The Rotifera were the least abundant among the three zooplankton groups. Brachionus formed the major component of Rotifera zooplankton at all the stations during the study period. In the Cladocera, Macrothrix was present during all the four seasons, while Pleuroxus, Oxyurella, Kurzia and, Diaphanosoma were rare. The CCA shows that maximal temporal variability in zooplankton abundance was explained by temperature and rainfall. ANOVA revealed no significant diff erence in mean zooplankton abundance among the seasons, but there was a statistically significant diff erence among the sites.

  15. 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.

  16. Zooplankton community of the Vitória Bay estuarine system (Southeastern Brazil: Characterization during a three-year study

    Directory of Open Access Journals (Sweden)

    José Mauro Sterza

    2006-09-01

    Full Text Available In order to characterize the zooplankton community at the Vitória Bay estuarine system (Southeastern Brazil, samples were collected in 10 sampling stations during a three-year study (1998-2000, every three months. A total of 64 taxa were identified.Copepoda contributed with the highest species number (49 in the community, especially with Acartia lilljeborgi,Acartia tonsa,Paracalanus parvus,P. quasimodo,Parvocalanus crassirostris,Temora turbinata,Oithona hebes,Oithona oculata and Euterpina acutifrons. Highest abundances occurred in the summer of 2000. Diversity indexes were higher at the estuary mouth. Zooplankton composition was characterized by coastal and estuarine species, their distribution being influenced mainly by the salinity variation in this estuarine system.Com o objetivo de caracterizar a comunidade zooplanctônica no sistema estuarino Baía de Vitória/Canal da Passagem, Vitória, E.S., foram coletadas amostras em dez pontos amostrais, trimestralmente durante três anos (1998-2000. Um total de 64 táxons foram identificados. Copepoda contribuiu com o maior número de espécies (49 na comunidade, destacando-se Acartia lilljeborgi,Acartia tonsa,Paracalanus parvus,Paracalanus quasimodo,Parvocalanus crassirostris,Temora turbinata,Oithona hebes,Oithona oculata e Euterpina acutifrons. A maior abundância ocorreu no verão do ano 2000. Os índices de diversidade foram maiores na entrada do estuário. A composição do zooplâncton se caracterizou por apresentar espécies estuarinas e costeiras, sendo a distribuição destas espécies influenciada principalmente pela variação dos valores de salinidade no estuário.

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

    Directory of Open Access Journals (Sweden)

    Elena Gorokhova

    Full Text Available 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

  18. 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

  19. 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.

  20. 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

    inclusion improves zooplankton growth models. We found that carbon percentage is continuous, but that species are not distributed homogenously along this axis. To assess variability of this trait in situ, we investigated the distribution of biomass across the range of carbon percentage for a zooplankton......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...... time series at station L4 off Plymouth, UK. This showed separate biomass peaks for gelatinous and crustacean taxa, however, carbon percentage varied 8-fold within the gelatinous group. Species with high carbon mass had lower carbon percentage, allowing separation of the counteracting effects...

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. Environmental changes and zooplankton temporal and spatial variation in a disturbed Brazilian coastal lagoon.

    Science.gov (United States)

    Branco, C W C; Kozlowsky-Suzuki, B; Esteves, F A

    2007-05-01

    The Imboassica lagoon, located in the Municipality of Macaé (RJ), is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.

  6. Environmental changes and zooplankton temporal and spatial variation in a disturbed brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    CWC. Branco

    Full Text Available The Imboassica lagoon, located in the Municipality of Macaé (RJ, is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.

  7. {sup 137}Cs concentration in zooplankton and its relation to taxonomic composition in the western North Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Kaeriyama, Hideki [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan)], E-mail: hideki_k@nirs.go.jp; Watabe, Teruhisa [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan); Kusakabe, Masashi [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan); Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2008-12-15

    To study the role of zooplankton in the transport of {sup 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 {sup 137}Cs in zooplankton varied from 11 to 24 mBq kg wet{sup -1} and were higher in October 2005 than in June 2006. The elevated abundance of gelatinous zooplankton probably led to higher concentration of {sup 137}Cs in zooplankton in October 2005. Annual export fluxes of {sup 137}Cs by ontogenetic vertical migrant copepods were estimated to be 0.8 and 0.6 mBq m{sup -2} year{sup -1} at 200 and 1000 m depths, respectively; this suggested that transport of {sup 137}Cs by zooplankton may be no trivial pathway.

  8. DNA Barcoding of Zooplankton in the Hampton Roads Area: A Biodiversity Assessment

    Science.gov (United States)

    Salcedo, A.; Rodríguez, Á. E.; Gibson, D. M.

    2016-02-01

    The study of zooplankton biodiversity and distribution is crucial to understand oceanic ecosystems and anticipate the effects of climate change. Previously, identification of zooplankton relied in morphological identification employed by expert taxonomists. DNA barcoding, a technique that uses the mitochondrial DNA (mtDNA) Cytochrome Oxidase 1 (CO1) gene is widely used for taxonomic identification. Thus, this molecular technique will be used to begin a detailed characterization of zooplankton diversity, abundance and community structure in the Hampton Roads Area (HRA). Stations 1 (Jones Creek) and 3 (lower Chesapeake Bay) were sampled in June 19, 2015. Stations 1, 2 (James River), and 3 were sampled in September 2015. Zooplankton samples were collected in triplicates with a 0.5m, 200 µm mesh net. Physical parameters (dissolved oxygen, salinity, temperature and, water transparency) were measured. Species identified as Opistonema oglinum (Atlantic Thread Herring) and Paracalanus parvus copepods were found at station 3; Anchoa mitchilli and Acartia tonsa copepods were found at stations 1 and 3. This study indicates that mtDNA-CO1 barcoding is suitable to identify zooplankton to the species level and helps validate DNA barcoding as a faster, more accurate taxonomic approach. The long term objective of this project is to provide a comprehensive assessment of zooplankton in the HRA and to generate a reference record for broad monitoring programs; vital for a better understanding and management of ecologically and commercially important species.

  9. 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.

  10. 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

  11. 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.

  12. 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.

    and internal waves may cause zooplankton abundance. Average biomass values in high sea surface temperature areas were higher (0.30 ml.m/3) than at the other stations (0.07 ml.m/3). Crustacean eggs, fish eggs and mysids clustered in pockets of abnormally high...

  13. 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.

    station (lat. 22 degrees 07'N and long. 67 degrees 03'E) and was due to swarm of gammarid amphipods and shoal of sergestid shrimp Acetes johni. Herbivores dominated the zooplankton community and copepods were most abundant (36.9 to 71.7%). The other...

  14. 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.

    tunicates which are able to feed on very small particles. It would seem that the Arabian Sea sustains a large biomass of mesopelagic fishes (about 100 million tonnes), mainly myctophids. They mostly live in the core of oxygen minimum layer and ascend...

  15. Mesozooplankton abundance and distribution in association with hydrography on Hanna Shoal, NE Chukchi Sea, during August 2012 and 2013

    Science.gov (United States)

    Ashjian, Carin J.; Campbell, Robert G.; Gelfman, Celia; Alatalo, Philip; Elliott, Stephen M.

    2017-10-01

    Hanna Shoal, in the northeastern Chukchi Sea, is potentially vulnerable to ecosystem disruption under ongoing climate change, however aspects of its ecology, particularly of its zooplankton, have been poorly understood. Mesozooplankton distribution, taxonomic composition, and abundance were described from across Hanna Shoal in August 2012 and 2013 as part of the multidisciplinary COMIDA Hanna Shoal Program. Zooplankton were collected using vertical tows of paired Bongo nets equipped with 150-μm and 500-μm mesh nets; samples from the 150-μm mesh nets were enumerated to identify and count taxa, copepod species, and copepod life stages. Haplotypes of the mitochondrial cytochrome c oxidase I (mtCOI) gene were used to differentiate Bering and Arctic haplotype groups of the copepod Calanus glacialis and to differentiate C. glacialis and its close congener C. marshallae. The meroplankton, particularly bivalve larvae and in 2012 echinoderm larvae, were an important component of the zooplankton and were of greater abundance on the eastern portion of the Shoal than elsewhere. Regions identified on the basis of different taxonomic compositions were associated with different water masses and current pathways. The northeast corner of the Shoal in particular was distinct from the remainder of the Shoal and from Barrow Canyon, with both different life stage compositions and unique Arctic haplotypes of the mtCOI gene for C. glacialis/marshallae, suggesting populations at those locations originated in the Arctic Ocean rather than the Bering Sea. Bering Sea Summer water, and intrinsic plankton, was observed in the southwest portion of the Shoal. Comparisons with historic and recent studies done near Hanna Shoal demonstrated that similar plankton compositions were present across a broad region of the Chukchi Sea and that abundances of the copepod C. glacialis appear to be increasing on the time scale of decades, potentially through increased input from the northern Bering Sea

  16. 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...

  17. 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.

  18. Preliminary census of zooplanktons and phytoplanktons community ...

    African Journals Online (AJOL)

    The zooplankton and phytoplankton community of Ajeko Stream, North Central Nigeria were assessed between October and December 2010. Prior to sampling, Temperature, Transparency, Dissolve Oxygen and pH were evaluated. Zooplankton and phytoplanktons were sampled using plankton net of 20μm diameter with a ...

  19. 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.

  20. 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.

  1. 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

  2. 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 ...

  3. Biodiversity of zooplankton communities in the Upper Paraná River floodplain: interannual variation from long-term studies

    Directory of Open Access Journals (Sweden)

    FA. Lansac-Tôha

    Full Text Available We investigated the effect of interannual variation of hydrosedimentological regime and connectivity on the zooplankton biodiversity in the Upper Paraná River floodplain. Zooplankton samplings were undertaken between 2000 and 2007, in different environments of the floodplain, including connected and isolated floodplain lakes, backwaters, rivers and channels. The zooplankton included 541 species. Rotifers showed the highest species richness and abundance. Among the zooplankton species, 71 represent new occurrence records for the floodplain. The species accumulation curve showed a continuous increase in gamma diversity, demonstrating the importance of long-term research for accurate knowledge of biodiversity in heterogeneous and dynamic ecosystems, such as the floodplains. Interannual beta diversity among studied years indicated a lesser alteration in community composition in 2001, when a long limnophase period was observed. In most of the environments, the highest species richness values were related to the greatest flooding amplitudes. Flooding amplitude, which is associated with connectivity, favors faunal exchange amongst the environments and between the pelagic and littoral zones. This explains the occurrence of both planktonic and non-planktonic species within the community. On the other hand, mean zooplankton abundance values were higher when a long isolation period occurred. Differences between the potamophase and limnophase amplitude associated with connectivity among the environments were the most important factors for the structure and dynamics of the zooplankton community in the Upper Paraná River floodplain.

  4. Biodiversity of zooplankton communities in the Upper Paraná River floodplain: interannual variation from long-term studies.

    Science.gov (United States)

    Lansac-Tôha, F A; Bonecker, C C; Velho, L F M; Simões, N R; Dias, J D; Alves, G M; Takahashi, E M

    2009-06-01

    We investigated the effect of interannual variation of hydrosedimentological regime and connectivity on the zooplankton biodiversity in the Upper Paraná River floodplain. Zooplankton samplings were undertaken between 2000 and 2007, in different environments of the floodplain, including connected and isolated floodplain lakes, backwaters, rivers and channels. The zooplankton included 541 species. Rotifers showed the highest species richness and abundance. Among the zooplankton species, 71 represent new occurrence records for the floodplain. The species accumulation curve showed a continuous increase in gamma diversity, demonstrating the importance of long-term research for accurate knowledge of biodiversity in heterogeneous and dynamic ecosystems, such as the floodplains. Interannual beta diversity among studied years indicated a lesser alteration in community composition in 2001, when a long limnophase period was observed. In most of the environments, the highest species richness values were related to the greatest flooding amplitudes. Flooding amplitude, which is associated with connectivity, favors faunal exchange amongst the environments and between the pelagic and littoral zones. This explains the occurrence of both planktonic and non-planktonic species within the community. On the other hand, mean zooplankton abundance values were higher when a long isolation period occurred. Differences between the potamophase and limnophase amplitude associated with connectivity among the environments were the most important factors for the structure and dynamics of the zooplankton community in the Upper Paraná River floodplain.

  5. Simulated eutrophication and browning alters zooplankton nutritional quality and determines juvenile fish growth and survival.

    Science.gov (United States)

    Taipale, Sami Johan; Kahilainen, Kimmo Kalevi; Holtgrieve, Gordon William; Peltomaa, Elina Talvikki

    2018-03-01

    The first few months of life is the most vulnerable period for fish and their optimal hatching time with zooplankton prey is favored by natural selection. Traditionally, however, prey abundance (i.e., zooplankton density) has been considered important, whereas prey nutritional composition has been largely neglected in natural settings. High-quality zooplankton, rich in both essential amino acids (EAAs) and fatty acids (FAs), are required as starting prey to initiate development and fast juvenile growth. Prey quality is dependent on environmental conditions, and, for example, eutrophication and browning are two major factors defining primary producer community structures that will directly determine the nutritional quality of the basal food sources (algae, bacteria, terrestrial matter) for zooplankton. We experimentally tested how eutrophication and browning affect the growth and survival of juvenile rainbow trout ( Oncorhynchus mykiss ) by changing the quality of basal resources. We fed the fish on herbivorous zooplankton ( Daphnia ) grown with foods of different nutritional quality (algae, bacteria, terrestrial matter), and used GC-MS, stable isotope labeling as well as bulk and compound-specific stable isotope analyses for detecting the effects of different diets on the nutritional status of fish. The content of EAAs and omega-3 (ω-3) polyunsaturated FAs (PUFAs) in basal foods and zooplankton decreased in both eutrophication and browning treatments. The decrease in ω-3 PUFA and especially docosahexaenoic acid (DHA) was reflected to fish juveniles, but they were able to compensate for low availability of EAAs in their food. Therefore, the reduced growth and survival of the juvenile fish was linked to the low availability of DHA. Fish showed very low ability to convert alpha-linolenic acid (ALA) to DHA. We conclude that eutrophication and browning decrease the availability of the originally phytoplankton-derived DHA for zooplankton and juvenile fish, suggesting

  6. 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.

  7. Latitudinal comparisons of equatorial Pacific zooplankton

    Science.gov (United States)

    Roman, M. R.; Dam, H. G.; Le Borgne, R.; Zhang, X.

    Zooplankton biomass and rates of ingestion, egestion and production in the equatorial Pacific Ocean along 140°W and 180° exhibit maximum values in the High-Nutrient Low-Chlorophyll (HNLC) zone associated with equatorial upwelling (5°S-5°N) as compared to the more oligotrophic regions to the north and south. Zooplankton biomass and rates are not usually highest on the equator, but increase "downstream" of the upwelling center as the zooplankton populations exhibit a delayed response to enhanced phytoplankton production. The vertical distribution of zooplankton biomass in the equatorial HNLC area tends to be concentrated in surface waters and is more uniform with depth in oligotrophic regions to the north and south of the equatorial upwelling zone. In general, the amount of mesozooplankton (>200 μm) carbon biomass is approximately 25% of estimated phytoplankton biomass and 30% of bacterial biomass in the HNLC area of the equatorial Pacific Ocean. Zooplankton grazing on phytoplankton is low in the equatorial Pacific Ocean, generally migrant zooplankton in the HNLC zone is a minor fraction of the gravitational flux (2% at 140°W, 4% at 180°) but increases in the more oligotrophic regions to the north and south where there is a deeper mixed layer and a greater relative proportion of diel migrant zooplankton.

  8. Zooplankton responses to increasing sea surface temperatures in the southeastern Australia global marine hotspot

    Science.gov (United States)

    Kelly, Paige; Clementson, Lesley; Davies, Claire; Corney, Stuart; Swadling, Kerrie

    2016-10-01

    Southeastern Australia is a 'hotspot' for oceanographic change. Here, rapidly increasing sea surface temperatures, rising at more than double the global trend, are largely associated with a southerly extension of the East Australian Current (EAC) and its eddy field. Maria Island, situated at the southern end of the EAC extension at 42°S, 148°E, has been used as a site to study temperature-driven biological trends in this region of accelerated change. Zooplankton have short life cycles (usually Australia are responding to increased temperatures through relocation, long-term increases in warm-water species and a shift towards a zooplankton community dominated by small copepods. The biological trends present evidence of extended EAC influence at Maria Island into autumn and winter months, which has allowed for the rapid establishment of warm-water species during these seasons, and has increased the similarity between Maria Island and the more northerly Port Hacking zooplankton community. Generalised Linear Models (GLM) suggest the high salinity and low nutrient properties of EAC-water to be the primary drivers of increasing abundances of warm-water species off southeastern Australia. Changes in both the species composition and size distribution of the Maria Island zooplankton community will have effects for pelagic fisheries. This study provides an indication of how zooplankton communities influenced by intensifying Western Boundary currents may respond to rapid environmental change.

  9. 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.

  10. 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

  11. 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...... a large abundance of copepods performing DVM (up during night and down during day). Migration behavior was expressed differently among the abundant groups with either a strong DVM (euphausiids), an absence of DVM (i.e., permanently deep; ostracods) or a marked DVM, driven by strong surface avoidance...

  12. 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...

  13. 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...

  14. Toxic effects of domestic sewage on zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

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

    The toxic effects of raw domestic sewage on different groups of zooplank-ton, was tested in the laboratory for evaluating acute toxicity. 24 hr., LC-50 values for larvae of stomatopods, gastropods and chaetognaths (2-7% concentration) indicated...

  15. 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.

  16. 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.

  17. Seasonal changes in zooplankton swimmer community collected by sediment trap moored in the western North Pacific Ocean

    Science.gov (United States)

    Yokoi, N.; Honda, M. C.; Matsuno, K.; Yamaguchi, A.

    2016-02-01

    For high-latitude oceanic region, life cycle of zooplankton is difficult to evaluate by ordinary ship-board observation. To overcome this problem, zooplankton monitoring on swimmer samples collected by sediment trap may be a powerful tool. In this study, we studied seasonal changes in zooplankton community based on the swimmer samples (>1 mm) collected by a sediment trap moored at 200 m depth at St. K2 (47°N, 160°E) in the western subarctic Pacific with one- to two-week intervals during July 2013 to May 2014. Zooplankton abundance and biomass showed clear seasonal pattern, and were higher during July-August. Cluster analysis (Bray-Curtis methods) separated samples into three groups. Occurrence of each group had clear seasonal pattern: i.e. group A characterized with high abundance with dominance of copepods Eucalanus bungii and Neocalanus plumchrus occurred during July to September, followed by group B with few abundance dominated by chaetognaths during October to December, then group C dominated by Neocalanus cristatus and Paraeuchaeta elongata during January to March. For dominant copepods, seasonal changes in population structure, lipid content and gonad developmental stage were observed. Thus, most males of E. bungii were C4 and C5 until February, while the composition of adults (C6M) suddenly increased and reached 80% at end of March. These drastic changes in copepod population structure are considered as a reflection of their arousal from diapause at that depth. Carnivorous P. elongata showed high abundance during March to July, and both egg-sac-carrying and spermatophore-attached adult females (C6F) were occurred during that period. These facts suggest that active reproduction of P. elongata was at that season. Results of this study suggest that seasonal monitoring on zooplankton swimmer collected by sediment trap is a powerful tool to evaluate life cycle of the oceanic zooplankton species.

  18. Comparison of acoustical and optical zooplankton measurements using an acoustic scattering model: A case study from the Arctic frontal zone

    Directory of Open Access Journals (Sweden)

    Szczucka Joanna

    2016-03-01

    Full Text Available High-frequency acoustic measurements supplemented by a modern optical method, Laser Optical Plankton Counter (LOPC, allowed us to perform a comparative analysis through the application of a mathematical model. We have studied the correspondence between measured and modelled echoes from zooplankton aggregations consisted mainly of two Calanus species. Data were collected from the upper 50 m water layer within the hydrographical frontal zone on the West Spitsbergen Shelf. The application of a “high-pass” model of sound scattering by fluid-like particles to the distribution of zooplankton sizes measured by LOPC resulted mostly in very good agreement between the measured (420 kHz BioSonics and modelled values, except for cases with very low zooplankton abundance or with occurrence of stronger scatterers (e.g. macrozooplankton, fish. An acoustic model validated for the elastic parameters of zooplankton confirmed that particles smaller than 1mmin diameter, although highly abundant, did not contribute significantly to the sound scattering process at a frequency of 420 kHz. The implementation of diverse complementary methods has great potential to obtain high spatial and temporal resolution in zooplankton distribution studies; however, their compatibility has to be tested first.

  19. 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...

  20. Monsoon regime in the Indian Ocean and zooplankton variability

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    The monsoonal effects on zooplankton lead to characteristic zoogeographic patterns in the open ocean and coastal waters. The evaluation of zooplankton variability in the Indian Ocean is presented in three sections: the open ocean, coastal waters...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.

    Empirical models based on regression analysis are derived using published values of phytoplankton and crustacean zooplankton biomass from Indian Ocean. Three regression models are derived. There is significant correlation between zooplankton...

  2. Grazing and excretion by zooplankton in the Peru upwelling system during April 1977

    Science.gov (United States)

    Dagg, M.; Cowles, T.; Whitledge, T.; Smith, S.; Howe, S.; Judkins, D.

    1980-01-01

    Rates of ingestion and excretion by adult females of the copepods Calanus chilensis, Eucalanus inermis, and Centropages brachiatus were measured in natural seawater during a cruise in the Peru upwelling system during April 1977. Simultaneously, zooplankton samples were collected for later determination of the abundance and distribution of these and other species. For these three organisms, feeding, and excretion rates of individuals are combined with information on the animal concentrations to estimate the grazing stress on the phytoplankton at each station, and to estimate the excretory nitrogen produced at each station. Comparison of grazing stresses with measured rates of primary production indicates that these large copepods were harvesting less than 5% of the daily phytoplankton production. Comparison of the nitrogen excretion rates with the amounts of excreted nitrogen in the water column indicates that less than 3% of the ambient excretory nitrogen was produced daily by these copepods. The importance of the abundant small zooplankton in the system is suggested.

  3. 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...

  4. 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...

  5. 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.

  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. Fish-mediated trait compensation in zooplankton

    DEFF Research Database (Denmark)

    Hylander, Samuel; Souza, M.S.; Balseiro, E.

    2012-01-01

    predation and UVR defences. 3. Zooplankton exposed to fish predator cues (no direct predation) reduced their pigmentation by c. 30% in 20 days. However, they were able to rapidly counteract negative UVR effects by increasing the activity of antioxidant defences such as glutathione S-transferase (GST). When...... pigmentation and antioxidant enzymes are flexible UVR defence systems, which can be induced when needed. Zooplankton may employ antioxidant defences when pigmentation is reduced to counteract predation risk and thereby rapidly respond to detrimental effects of UVR exposure, that is, they can compensate one......1. Environmental factors fluctuate spatially and temporally, and organisms that can alter phenotype in response to these changes may increase their fitness. Zooplankton are known to be able to induce body pigmentation in response to ultraviolet radiation (UVR) and to reduce the pigmentation when...

  8. 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 ...

  9. The zooplankton of Msikaba estuary | Wooldridge | African Zoology

    African Journals Online (AJOL)

    Stratification is well developed in Msikaba estuary and has a major influence on the distribution of the zooplankton. The oligohaline zooplankton component does not become well established, while marine zooplankton organisms penetrate relatively far up the estuary in the high salinity bottom waters. The euryhaline ...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Ramaiah, Neelam

    The nearshore waters of Bombay sustain a rich and diverse zooplankton fauna. Continuous observations for a period of 15 months indicated a variation from 0.4 to 19.9 mg C.m sup(3) (av. 4.3 mg C.m sup(-3)) in zooplankton biomass. The zooplankton...

  11. 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...

  12. Widely used marine seismic survey air gun operations negatively impact zooplankton.

    Science.gov (United States)

    McCauley, Robert D; Day, Ryan D; Swadling, Kerrie M; Fitzgibbon, Quinn P; Watson, Reg A; Semmens, Jayson M

    2017-06-22

    Zooplankton underpin the health and productivity of global marine ecosystems. Here we present evidence that suggests seismic surveys cause significant mortality to zooplankton populations. Seismic surveys are used extensively to explore for petroleum resources using intense, low-frequency, acoustic impulse signals. Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (~3-4 dB drop within 15-30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton. Impacts were observed out to the maximum 1.2 km range sampled, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage. There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.

  13. 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.

  14. THE ZOOPLANKTON COMMUNITY OF THE MHLATHUZE ...

    African Journals Online (AJOL)

    This study investigates the composition of the zooplankton community of the new estuary 20 years after its construction and compares it with historical data. Compared with the ... Salinity levels throughout the new estuary were close to that of seawater, except for a few occasions during particularly strong freshwater inflows.

  15. 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

  16. A compilation of quantitative functional traits for marine and freshwater crustacean zooplankton.

    Science.gov (United States)

    Hébert, Marie-Pier; Beisner, Beatrix E; Maranger, Roxane

    2016-04-01

    This data compilation synthesizes 8609 individual observations and ranges of 13 traits from 201 freshwater and 191 marine crustacean taxa belonging to either Copepoda or Cladocera, two important zooplankton groups across all major aquatic habitats. Most data were gathered from the literature, with the balance being provided by zooplankton ecologists. With the aim of more fully assessing zooplankton effects on elemental processes such as nitrogen (N), phosphorus (P) and carbon (C) stocks and fluxes in aquatic ecosystems, this data set provides information on the following traits: body size (length and mass), trophic group, elemental and biochemical corporal composition (N, P, C, lipid and protein content), respiration rates, N- and P-excretion rates, as well as stoichiometric ratios. Although relationships for zooplankton metabolism as a function of body mass or requirements have been explored in the past three decades, data have not been systematically compiled nor examined from an integrative and large-scale perspective across crustacean taxa and habitat types. While this contribution likely represents the most comprehensive assembly of traits for both marine and freshwater species, this data set is not exhaustive either. As a result, this compilation also identifies knowledge gaps: a fact that should encourage researchers to disclose information they may have to help complete such databases. This trait matrix is made available for the first time in this data paper; prior to its release, the data set has been analyzed in a meta-analysis published as a companion paper. This data set should prove extremely valuable for aquatic ecologists for trait-based characterization of plankton community structure as well as biogeochemical modeling. These data are also well-suited for deriving shortcut relationships that predict more difficult to measure trait values, most of which can be directly related to ecosystem properties (i.e., effect traits), from simpler traits (e

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Repeated flood disturbance enhances rotifer dominance and diversity in a zooplankton community of a small dammed mountain pond

    Directory of Open Access Journals (Sweden)

    Carmen Gabaldón

    2016-12-01

    Full Text Available The zooplankton community in a relatively small and mountain pond was studied during the spring growing season. To investigate which factors operate in the community structure, we explored several physical conditions, such as high inflows, and the biotic dynamics of the main zooplankton groups (i.e., rotifers, cladocerans and copepods.  Two extreme flood events occurred during the investigated period and caused dramatic changes in physical conditions and reduction of the planktonic community abundances. The short period between both high-flow events was enough for the recovery of microplankton, but not for the metazoan zooplankton. Our results are in agreement with the common situation in which high flood events commonly favour rotifers over crustaceans, likely due to rotifer species have great colonization ability and grow faster. However, we found that the dominance of rotifers over crustaceans in our system is evidenced by an extremely, unusual high ratio between their abundances.  We observed that, at the time of the great floods, crustacean abundances as well as rotifer populations notably decreased until near zero values. Although rotifer abundance began declining before high floods, the decrease was particularly notable when the great flood happened.  Our results evidenced that i dilution rate and temperature were the main drivers which are operating in the structure of the zooplankton community; and ii no negative biotic interactions were detected between large and small cladocerans and rotifers. Additionally, we found surprisingly that a repeated disturbance caused by high flood events does increase the species diversity of rotifers. Finally, our study also detected some cues which may indicate that diapausing egg bank is also playing an important role in the zooplankton community, favouring the dominance of rotifers; however, this phenomenon deserves further studies. 

  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. 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

  4. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhofer, G.A.

    1992-09-25

    This study sought to determine and understand the major processes governing the abundance, distribution, composition and eventual fate of zooplankton on the southeastern shelf of the US in relation to water circulation. Over much of the shelf circulation is dominated by the Gulf Stream and/or atmospheric forcing. Most of our studies concentrated on processes on the middle and outer shelf. On the latter, pronounced biological production occurs year-round at frequent intervals and is due to Gulf Stream eddies which move by at an average frequency of one every week. These eddies are rich in nutrients which, when upwelled into the euphoric zone, lead to pronounced primary production which then triggers zooplankton production.

  5. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhofer, G.A.

    1992-09-25

    This study sought to determine and understand the major processes governing the abundance, distribution, composition and eventual fate of zooplankton on the southeastern shelf of the US in relation to water circulation. Over much of the shelf circulation is dominated by the Gulf Stream and/or atmospheric forcing. Most of our studies concentrated on processes on the middle and outer shelf. On the latter, pronounced biological production occurs year-round at frequent intervals and is due to Gulf Stream eddies which move by at an average frequency of one every week. These eddies are rich in nutrients which, when upwelled into the euphoric zone, lead to pronounced primary production which then triggers zooplankton production.

  6. Composition and abundance of rotifera in Ikpoba river, Benin, Edo ...

    African Journals Online (AJOL)

    The present study investigated some selected physico-chemical parameters and the composition and abundance of rotifers in Ikpoba River from June to November 2009 to ascertain its ecological status due to the increasing anthropogenic activities on the river using rotifers. Water and zooplankton samples were collected ...

  7. Seasonal zooplankton dynamics in Lake Michigan: disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

    Science.gov (United States)

    Vanderploeg, Henry A.; Pothoven, Steven A.; Fahnenstiel, Gary L.; Cavaletto, Joann F.; Liebig, James R.; Stow, Craig Stow; Nalepa, Thomas F.; Madenjian, Charles P.; Bunnell, David B.

    2012-01-01

    We examined seasonal dynamics of zooplankton at an offshore station in Lake Michigan from 1994 to 2003 and 2007 to 2008. This period saw variable weather, declines in planktivorous fish abundance, the introduction and expansion of dreissenid mussels, and a slow decline in total phosphorus concentrations. After the major expansion of mussels into deep water (2007–2008), chlorophyll in spring declined sharply, Secchi depth increased markedly in all seasons, and planktivorous fish biomass declined to record-low levels. Overlaying these dramatic ecosystem-level changes, the zooplankton community exhibited complex seasonal dynamics between 1994–2003 and 2007–2008. Phenology of the zooplankton maximum was affected by onset of thermal stratification, but there was no other discernable effect due to temperature. Interannual variability in zooplankton biomass during 1994 and 2003 was strongly driven by planktivorous fish abundance, particularly age-0 and age-1 alewives. In 2007–2008, there were large decreases in Diacyclops thomasi and Daphnia mendotae possibly caused by food limitation as well as increased predation and indirect negative effects from increases in Bythotrephes longimanus abundance and in foraging efficiency associated with increased light penetration. The Bythotrephes increase was likely driven in part by decreased predation from yearling and older alewife. While there was a major decrease in epilimnetic–metalimnetic herbivorous cladocerans in 2007–2008, there was an increase in large omnivorous and predacious calanoid copepods, especially those in the hypolimnion. Thus, changes to the zooplankton community are the result of cascading, synergistic interactions, including a shift from vertebrate to invertebrate planktivory and mussel ecosystem impacts on light climate and chlorophyll.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Indicator taxa revisited: useful for conservation planning?

    DEFF Research Database (Denmark)

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

    2009-01-01

    their usefulness as indicators of broader biodiversity. Here we assess several aspects, such as influence of species number, of indicator taxa for three extensive data sets to improve our insight into the effectiveness of indicator taxa. Location:  Denmark, sub-Saharan Africa and Uganda. Methods:  First, we...... sets: sub-Saharan Africa (4,039 spp.), Denmark (847 spp.) and Uganda (2,822 spp.). Results:  We overall found that indicator taxa comprising a greater number of species tend to perform better than indicator taxa with fewer species (e.g. 488 mammal spp. outperform 210 snake spp.), although...

  13. Climate-related variability in abundance of mesozooplankton in the northern Gulf of Alaska 1998-2009

    Science.gov (United States)

    Sousa, Leandra; Coyle, Kenneth O.; Barry, Ronald P.; Weingartner, Thomas J.; Hopcroft, Russell R.

    2016-10-01

    Significant changes in fisheries resources have occurred in the Gulf of Alaska (GOA) in the mid 1970s, with an increase in groundfish and a decrease in crab and shrimp populations. Increased fishing pressure and such events suggest that the GOA is susceptible to climate variation; however the mechanistic links between ecosystem change and climate remain unclear. At-sea surveys were undertaken during the month of May from 1998 to 2009 to collect data on zooplankton abundance and water mass properties in the northern GOA. Significant changes in temperature, salinity and zooplankton abundance were identified during this period. The euphausiid Thysanoessa inermis and the copepod Calanus marshallae had increased abundances in years when there was a strong phytoplankton spring bloom preceded by anomalously cold winters. The euphausiid Euphausia pacifica and the copepods Pseudocalanus spp., Neocalanus plumchrus/flemingeri, and Oithona spp. were more resilient to relatively high mean water temperatures. High zooplankton abundances in years of substantial cross-shelf mixing suggest that iron and nutrient transport between the shelf and oceanic domains are essential for sustaining high zooplankton populations via phytoplankton blooms. The abundance of zooplankton in the northern GOA is highly influenced by advective processes and changes in temperature. Further understanding of biological and physical mechanisms that control the GOA ecosystem are of major importance to predict the response of zooplankton communities to environmental changes.

  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. Evidence of microplastics in samples of zooplankton from Portuguese coastal waters.

    Science.gov (United States)

    Frias, J P G L; Otero, V; Sobral, P

    2014-04-01

    Records of high concentrations of plastic and microplastic marine debris floating in the ocean have led to investigate the presence of microplastics in samples of zooplankton from Portuguese coastal waters. Zooplankton samples collected at four offshore sites, in surveys conducted between 2002 and 2008, with three different sampling methods, were used in this preliminary study. A total of 152 samples were processed and microplastics were identified in 93 of them, corresponding to 61% of the total. Costa Vicentina, followed by Lisboa, were the regions with higher microplastic concentrations (0.036 and 0.033 no. m⁻³) and abundances (0.07 and 0.06 cm³ m⁻³), respectively. Microplastic: zooplankton ratios were also higher in these two regions, which is probably related to the proximity of densely populated areas and inputs from the Tejo and Sado river estuaries. Microplastics polymers were identified using Micro Fourier Transformed Infrared Spectroscopy (μ-FTIR), as polyethylene (PE), polypropylene (PP) and polyacrylates (PA). The present work is the first report on the composition of microplastic particles collected with plankton nets in Portuguese coastal waters. Plankton surveys from regular monitoring campaigns conducted worldwide may be used to monitor plastic particles in the oceans and constitute an important and low cost tool to address marine litter within the scope of the Marine Strategy Framework Directive (2008/56/EC). Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Chlorophyll and zooplankton in microbasins along the Strait of Magellan - Beagle Channel passage

    Directory of Open Access Journals (Sweden)

    Madeleine Hamamé

    1999-12-01

    Full Text Available Distributions of chlorophyll and zooplankton were compared to temperature and salinity distributions along previously defined microbasins. Results were consistent for chlorophyll: 1.- Paso Ancho-Seno Magdalena showed a shallow chlorophyll maximum (ca. 5 mg m-3 at 0 - 20 m in a vertically homogeneous cold and brackish water column, 2.- Canal Magdalena-Canal Cockburn-Canal Brecknock had relatively lower chlorophyll concentrations (2-3 mg m-3 at 0-50 m, minor stratification of salinity and a surface lens of warmer water, 3.- Canal Ballenero-Brazo Noroeste had a subsurface layer of high chlorophyll concentration (> 4 mg m-3 in a vertically stratified water column of 2 salinity layers and 3 temperature layers, 4.- Canal Beagle presented a subsurface chlorophyll maximum (> 4 mg m-3 extending to the bottom, and vertically homogeneous salinity and temperature distribution. Chaetoceros spp.-dominated phytoplankton was a common feature in the entire area. Zooplankton distributions did not match the above mentioned subdivision of microbasins despite some trends along the passage. High relative abundance of invertebrate larvae in the zooplankton was associated with a matching response to the spring bloom and implies a strong bentho-pelagic coupling.

  17. The Influence of Individual Variability on Zooplankton Population Dynamics under Different Environmental Conditions

    Science.gov (United States)

    Bi, R.; Liu, H.

    2016-02-01

    Understanding how biological components respond to environmental changes could be insightful to predict ecosystem trajectories under different climate scenarios. Zooplankton are key components of marine ecosystems and changes in their dynamics could have major impact on ecosystem structure. We developed an individual-based model of a common coastal calanoid copepod Acartia tonsa to examine how environmental factors affect zooplankton population dynamics and explore the role of individual variability in sustaining population under various environmental conditions consisting of temperature, food concentration and salinity. Total abundance, egg production and proportion of survival were used to measure population success. Results suggested population benefits from high level of individual variability under extreme environmental conditions including unfavorable temperature, salinity, as well as low food concentration, and selection on fast-growers becomes stronger with increasing individual variability and increasing environmental stress. Multiple regression analysis showed that temperature, food concentration, salinity and individual variability have significant effects on survival of A. tonsa population. These results suggest that environmental factors have great influence on zooplankton population, and individual variability has important implications for population survivability under unfavorable conditions. Given that marine ecosystems are at risk from drastic environmental changes, understanding how individual variability sustains populations could increase our capability to predict population dynamics in a changing environment.

  18. Seasonal variation of the main zooplanktonic groups of the protected natural area estuary El Salado, Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    Navarro-Rodríguez, M.C.

    2015-01-01

    Full Text Available Estuarine systems are the most important aquatic natural resources of the nation from various perspectives; fisheries use them mainly through studies that allow the detection and evaluation of the areas of concentration of adults on reproduction phase and potentially exploitable species. This present paper analyzes the spatial and temporal variation of the abundance of zooplankton groups in the Estuary El Salado, Puerto Vallarta, Jalisco. Eight zooplanktonic trawls were conducted during diurnal periods from spring to winter 2001, trawls were superficial, lasting ten minutes, by using a standard “Zeppelin” net with a mesh size of 505 μm with a length of 1.50 m mouth width of 0.60 m which was equipped with a digital flow meter to calculate the volume of filtered water, abundance data were normalized to a volume of 1000 m3. The total catch was 101,968.4 organisms, represented in eleven groups, the brachyurans were the most important group in the order of abundance accounting for 44.5 %, followed by 24.1 % in chaetognaths, decapod with 6.78 %, euphausiids with 11.84 %, and less abundant copepods with 6.18 %, 3.37 % siphonophores small jellyfish, stomatopods 2.83 %, 0.22 % amphipods, cladocerans with 0.33 %, 0.08 % gastropods and finally rare organisms with 0.02 % (appendicular, polychaetes and cumaceans. Variations in both spatial and temporal abundance were influenced by tidal conditions as well as variations in temperature and salinity. All registered major zooplankton groups abundances were homogeneous in the four seasonal periods, however spring was characterized by low abundance, while for summer and winter, the highest values recorded were represented mainly by the Brachyura order, and those abundances were associated with two reproductive periods in both seasons.

  19. Seabird distribution, abundance and diets in the eastern and central Aleutian Islands

    OpenAIRE

    Jahncke, J; Coyle, KO; Hunt, GL

    2005-01-01

    We examined the hypothesis that seabird distribution, abundance and diets differ among the eastern and central Aleutian Islands in response to distinct marine environments and energy pathways in each region. Research cruises were conducted in June 2001 and May-June 2002. We determined the distribution, abundance, diet and prey consumption of seabirds, and related these to zooplankton abundance and water masses that possess different physical properties. We found that distribution, abundance a...

  20. 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.

  1. Offshore Wind Farms in the North Sea: Is there an effect on the zooplankton community?

    Science.gov (United States)

    Auch, Dominik; Dudeck, Tim; Callies, Ulrich; Riethmüller, Rolf; Hufnagl, Marc; Eckhardt, André; Ove Möller, Klas; Haas, Bianca; Spreitzenbarth, Stefan; van Beusekom, Justus; Walter, Bettina; Temming, Axel; Möllmann, Christian; Floeter, Jens

    2016-04-01

    The climate conference in Paris 2015 has resulted in ambitious goals to mitigate the extent of global climate warming within this century. In Germany, the expansion of renewable energy sources is without any alternative to match the own aims of greenhouse gas reductions. Therefore, in the German EEZ of the North Sea around 10 offshore wind farms (OWFs) are already working and more are currently planned or already under construction. At this already substantial level of offshore wind energy production little is known about the effects of OWFs on the pelagic ecosystem. Earlier investigations have shown an increase of benthic organisms settling on hard substrates provided by the power plant foundations. However, the effects of offshore power plants on lower trophic level organisms within the water column are poorly understood. Thus, we investigated the abundance and distribution of zooplankton within and around OWFs. The analysis was based on optical data derived from a Video Plankton Recorder (VPR). The VPR was mounted on a TRIAXUS system including a suite of different sensors, hence allowing to combine zooplankton information with ambient hydrographic parameters. The combination of the VPR and the TRIAXUS system enabled us to analyse continuous zooplankton and hydrographic data with a high spatial resolution. In this study, we present results of transects through the OWFs Global Tech I, BARD Offshore 1, and Alpha Ventus. The analysis exhibits distinct pattern in the spatial distribution both of physical state variables and of plankton organisms within the vicinity of OWFs, especially of meroplankton, the larval phase of benthic organisms. Keywords: Offshore Wind Farms, Zooplankton, TRIAXUS, Video Plankton Recorder, Meroplankton Corresponding author: Dominik Auch, Institute for Hydrobiology and Fisheries Science, University of Hamburg, Olbersweg 24, 22767 Hamburg, Germany; auch.dominik@web.de

  2. 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.

  3. 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...

  4. Effect of pig dung fertilizer on zooplankton production

    African Journals Online (AJOL)

    SARAH

    2014-12-29

    Dec 29, 2014 ... Objectives: To test the effect of pig dung fertilizer on zooplankton production in research station on wetlands at the University of ... Conclusions and application of findings: The zooplankton production is realizable with pig dung. ..... McQueen DJ, Johannes MRS, Post JR, Stewart TJ, Lean. DRS, 1989.

  5. Census of Marine Zooplankton CmarZ Information

    NARCIS (Netherlands)

    Pierrot-Bults, A.C.; Bucklin, A.

    2005-01-01

    The Census of Marine Zooplankton (CMarZ) will work toward a taxonomically comprehensive assessment of biodiversity of animal plankton throughout the world ocean. The project goal is to produce accurate and complete information on zooplankton species diversity, biomass, biogeographic distribution,

  6. 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 ...

  7. Wet season spatial occurrence of phytoplankton and zooplankton in ...

    African Journals Online (AJOL)

    Science World Journal ... Investigation into the spatial occurrence of wet season phytoplankton and zooplankton in Lagos lagoon, Nigeria was carried out in October, 2008 in 12 stations. A total of ... The wet season spectrum of the lagoon was dominated by diatoms for the phytoplankton and copepods for the zooplankton.

  8. Wet Season Spatial Occurrence Of Phytoplankton and Zooplankton

    African Journals Online (AJOL)

    Administrator

    ABSTRACT. Investigation into the spatial occurrence of wet season phytoplankton and zooplankton in Lagos lagoon, Nigeria was carried out in October, 2008 in 12 stations. A total of 36 species of phytoplankton from 21 genera, 20 zooplankton species from 17 genera and 10 juvenile forms were recorded for the study.

  9. Response of Cyprinus carpio hatchlings artemia, mixed zooplankton ...

    African Journals Online (AJOL)

    Experiments were conducted on the response of Cyprinus carpio to Artemia nauplii, mixed zooplankton and Yeast (single cell protein). The fish was fed two quantities of each diet, 100 and 150 ml artemia; 50-100 ml and 150-200 ml zooplankton; and 185 -195 and 200-250 ml yeast. They were fed twice daily There was no ...

  10. Diel vertical migration of zooplankton in a hypertrophic shallow ...

    African Journals Online (AJOL)

    Diel vertical migration of zooplankton in a hypertrophic shallow temperate lake, Germany. Brook Lemma. Abstract. Zooplankton as important links in the food web of aquatic ecosystems have been studied extensively. In current literature their diel vertical migration (DVM) is a highly discussed issue. In this investigation DVM ...

  11. 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

  12. 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

  13. Summer and winter differences in zooplankton biomass, distribution ...

    African Journals Online (AJOL)

    Zooplankton biomass in each size class was significantly, negatively related to sea surface temperature and integrated nitrate, but positively related to surface chlorophyll a and dissolved oxygen. Zooplankton biomass was significantly related to bottom depth, with greatest total biomass located inshore (<50 m). Distribution ...

  14. impact of physicochemical factors on zooplankton species richness

    African Journals Online (AJOL)

    DR. AMINU

    25cm diameter was used in collecting grab samples of zooplanktons through vertical hauling. Physicochemical parameters such as ... vertical migration of zooplankton, which affects their diurnal rhythms (Verma and Agarwal, 2007). ... Bompai industrial estate, and the confluence drains the water into Wasai reservoir.

  15. 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 ...

  16. 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...

  17. Indigenous species barcode database improves the identification of zooplankton.

    Directory of Open Access Journals (Sweden)

    Jianghua Yang

    Full Text Available Incompleteness and inaccuracy of DNA barcode databases is considered an important hindrance to the use of metabarcoding in biodiversity analysis of zooplankton at the species-level. Species barcoding by Sanger sequencing is inefficient for organisms with small body sizes, such as zooplankton. Here mitochondrial cytochrome c oxidase I (COI fragment barcodes from 910 freshwater zooplankton specimens (87 morphospecies were recovered by a high-throughput sequencing platform, Ion Torrent PGM. Intraspecific divergence of most zooplanktons was < 5%, except Branchionus leydign (Rotifer, 14.3%, Trichocerca elongate (Rotifer, 11.5%, Lecane bulla (Rotifer, 15.9%, Synchaeta oblonga (Rotifer, 5.95% and Schmackeria forbesi (Copepod, 6.5%. Metabarcoding data of 28 environmental samples from Lake Tai were annotated by both an indigenous database and NCBI Genbank database. The indigenous database improved the taxonomic assignment of metabarcoding of zooplankton. Most zooplankton (81% with barcode sequences in the indigenous database were identified by metabarcoding monitoring. Furthermore, the frequency and distribution of zooplankton were also consistent between metabarcoding and morphology identification. Overall, the indigenous database improved the taxonomic assignment of zooplankton.

  18. Activity of abundant and rare bacteria in a coastal ocean.

    Science.gov (United States)

    Campbell, Barbara J; Yu, Liying; Heidelberg, John F; Kirchman, David L

    2011-08-02

    The surface layer of the oceans and other aquatic environments contains many bacteria that range in activity, from dormant cells to those with high rates of metabolism. However, little experimental evidence exists about the activity of specific bacterial taxa, especially rare ones. Here we explore the relationship between abundance and activity by documenting changes in abundance over time and by examining the ratio of 16S rRNA to rRNA genes (rDNA) of individual bacterial taxa. The V1-V2 region of 16S rRNA and rDNA was analyzed by tag pyrosequencing in a 3-y study of surface waters off the Delaware coast. Over half of the bacterial taxa actively cycled between abundant and rare, whereas about 12% always remained rare and potentially inactive. There was a significant correlation between the relative abundance of 16S rRNA and the relative abundance of 16S rDNA for most individual taxa. However, 16S rRNA:rDNA ratios were significantly higher in about 20% of the taxa when they were rare than when abundant. Relationships between 16S rRNA and rDNA frequencies were confirmed for five taxa by quantitative PCR. Our findings suggest that though abundance follows activity in the majority of the taxa, a significant portion of the rare community is active, with growth rates that decrease as abundance increases.

  19. 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

  20. Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder

    DEFF Research Database (Denmark)

    Möller, Klas O.; St. John, Michael; Temming, Axel

    2012-01-01

    distribution patterns of fragile marine snow aggregates and zooplankton in the Baltic Sea during late spring 2002. By using this non-invasive optical sampling technique we recorded a peak in copepod abundance (ca. 18 ind. l−1) associated with a pronounced thin layer (50 to 55 m) of marine snow (maximum...... sampling does not collect marine snow quantitatively and cannot resolve so-called thin layers in which this interaction occurs. Hence, field evidence for the importance of the marine snow−zooplankton link is scarce. Here we employed a Video Plankton Recorder (VPR) to quantify small-scale (metres) vertical...

  1. Regional zooplankton biodiversity provides limited buffering of pond ecosystems against climate change.

    Science.gov (United States)

    Thompson, Patrick L; Shurin, Jonathan B

    2012-01-01

    1. Climate change and other human-driven environmental perturbations are causing reductions in biodiversity and impacting the functioning of ecosystems on a global scale. Metacommunity theory suggests that ecosystem connectivity may reduce the magnitude of these impacts if the regional species pool contains functionally redundant species that differ in their environmental tolerances. Dispersal may increase the resistance of local ecosystems to environmental stress by providing regional species with traits adapted to novel conditions. 2. We tested this theory by subjecting freshwater zooplankton communities in mesocosms that were either connected to or isolated from the larger regional species pool to a factorial manipulation of experimental warming and increased salinity. 3. Compensation by regional taxa depended on the source of stress. Warming tolerant regional taxa partially compensated for reductions in heat sensitive local taxa but similar compensation did not occur under increased salinity. 4. Dispersal-mediated species invasions dampened the effects of warming on summer net ecosystem productivity. However, this buffering effect did not occur in the fall or for periphyton growth, the only other ecosystem function affected by the stress treatments. 5. The results indicate that regional biodiversity can provide insurance in a dynamic environment but that the buffering capacity is limited to some ecosystem processes and sources of stress. Maintaining regional biodiversity and habitat connectivity may therefore provide some limited insurance for local ecosystems in changing environments, but is unable to impart resistance against all sources of environmental stress. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

  2. 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.

  3. Circadian Clock Involvement in Zooplankton Diel Vertical Migration.

    Science.gov (United States)

    Häfker, N Sören; Meyer, Bettina; Last, Kim S; Pond, David W; Hüppe, Lukas; Teschke, Mathias

    2017-07-24

    Biological clocks are a ubiquitous ancient and adaptive mechanism enabling organisms to anticipate environmental cycles and to regulate behavioral and physiological processes accordingly [1]. Although terrestrial circadian clocks are well understood, knowledge of clocks in marine organisms is still very limited [2-5]. This is particularly true for abundant species displaying large-scale rhythms like diel vertical migration (DVM) that contribute significantly to shaping their respective ecosystems [6]. Here we describe exogenous cycles and endogenous rhythms associated with DVM of the ecologically important and highly abundant planktic copepod Calanus finmarchicus. In the laboratory, C. finmarchicus shows circadian rhythms of DVM, metabolism, and most core circadian clock genes (clock, period1, period2, timeless, cryptochrome2, and clockwork orange). Most of these genes also cycle in animals assessed in the wild, though expression is less rhythmic at depth (50-140 m) relative to shallow-caught animals (0-50 m). Further, peak expressions of clock genes generally occurred at either sunset or sunrise, coinciding with peak migration times. Including one of the first field investigations of clock genes in a marine species [5, 7], this study couples clock gene measurements with laboratory and field data on DVM. While the mechanistic connection remains elusive, our results imply a high degree of causality between clock gene expression and one of the planet's largest daily migrations of biomass. We thus suggest that circadian clocks increase zooplankton fitness by optimizing the temporal trade-off between feeding and predator avoidance, especially when environmental drivers are weak or absent [8]. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. 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

  5. Multi-taxa trait and functional responses to physical disturbance.

    Science.gov (United States)

    Pedley, Scott M; Dolman, Paul M

    2014-11-01

    Examining assemblage trait responses to environmental stressors extends our understanding beyond patterns of taxonomic diversity and composition, with results potentially transferable among bioregions. But the degree to which trait responses may be generalized across taxonomic groups remains incompletely understood. We compared trait responses among carabids, spiders and plants to an experimentally manipulated gradient of physical disturbance, replicated in open habitats within a forested landscape. Recolonization of recently disturbed habitats is expected to favour species with traits that promote greater dispersal ability, independent of taxa. We specifically predicted that physical disturbance would increase the representation of carabids with smaller body size, wings or wing dimorphism, spiders able to disperse aerially, and plants with therophyte life-history and wind-dispersed seed. We sampled 197 arthropod species (14,738 individuals) and 164 species of plant. The strength of association between each trait and the disturbance intensity was quantified by correlating matrices of species by traits, species abundance by sites and sites by environment, with significance assessed by comparison with a null model. Responses of biological traits varied among taxa but could be consistently interpreted in terms of dispersal ability. Trait shifts for carabid and plant assemblages were as predicted and correspond to those observed in other disturbance regimes. Assemblages after disturbance comprised smaller and winged carabids, and smaller plants with wind-dispersed seed, consistent with selection for species with better dispersal ability. In contrast, aerial dispersal did not appear important in spider recolonization, instead terrestrial dispersal ability was suggested by the increased abundance of larger-bodied and cursorial species. However, larger spider body size was also associated with an active-hunting strategy, also favoured in the post-disturbance environment

  6. 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

  7. Flow disturbances generated by feeding and swimming zooplankton

    DEFF Research Database (Denmark)

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

    2014-01-01

    to minimize the fluid disturbance that they produce. By means of particle image velocimetry, we describe the fluid disturbances produced by feeding and swimming in zooplankton with diverse propulsion mechanisms and ranging from 10-µm flagellates to greater than millimeter-sized copepods. We show...... 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...

  8. 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.

    in the organism's body and its mean concentration in the ambient water. All metal concentrations in water are reported in ug l -1 where as in zooplankton the values are reported in ug g -1 dry weight. RESULTS The copepods were the most dominant zooplankton... Visakhapatnam and off Chennai transect (Fig.l&2) The iron levels in zooplankton (50962 ppm) and in water (2.81 ppb) off Visakhapatnam were nearly twice when compared with the respective values at the coastal stations of other transects. These higher levels can...

  9. 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

  10. 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.

  11. Zooplankton species identities and other data collected from zooplankton net casts in the NE Atlantic Ocean from DISCOVERY; 12 November 1969 to 01 July 1988 (NODC Accession 9500097)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton species identities and other data were collected by DISCOVERY using zooplankton net casts in the Northeast Atlantic Ocean. Data were collected from 12...

  12. Zooplankton data collected from THOMAS G. THOMPSON in TOGA Area of Pacific Ocean from zooplankton net casts; 30 January 1992 to 21 October 1992 (NODC Accession 9700054)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in the TOGA Area of Pacific Ocean from THOMAS G. THOMPSON. Data were collected from 30 January 1992 to 21...

  13. 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.

  14. The influence of a severe reservoir drawdown on springtime zooplankton and larval fish assemblages in Red Willow Reservoir, Nebraska

    Science.gov (United States)

    DeBoer, Jason A.; Webber, Christa M.; Dixon, Taylor A.; Pope, Kevin L.

    2016-01-01

    Reservoirs can be dynamic systems, often prone to unpredictable and extreme water-level fluctuations, and can be environments where survival is difficult for zooplankton and larval fish. Although numerous studies have examined the effects of extreme reservoir drawdown on water quality, few have examined extreme drawdown on both abiotic and biotic characteristics. A fissure in the dam at Red Willow Reservoir in southwest Nebraska necessitated an extreme drawdown; the water level was lowered more than 6 m during a two-month period, reducing reservoir volume by 76%. During the subsequent low-water period (i.e., post-drawdown), spring sampling (April–June) showed dissolved oxygen concentration was lower, while turbidity and chlorophyll-a concentration were greater, relative to pre-drawdown conditions. Additionally, there was an overall increase in zooplankton density, although there were differences among taxa, and changes in mean size among taxa, relative to pre-drawdown conditions. Zooplankton assemblage composition had an average dissimilarity of 19.3% from pre-drawdown to post-drawdown. The ratio of zero to non-zero catches was greater post-drawdown for larval common carp and for all larval fishes combined, whereas we observed no difference for larval gizzard shad. Larval fish assemblage composition had an average dissimilarity of 39.7% from pre-drawdown to post-drawdown. Given the likelihood that other dams will need repair or replacement in the near future, it is imperative for effective reservoir management that we anticipate the likely abiotic and biotic responses of reservoir ecosystems as these management actions will continue to alter environmental conditions in reservoirs.

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

    NARCIS (Netherlands)

    Ger, K.A.; Hansson, L-A.; Lurling, M.

    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. The emphasis on oversimplified studies

  16. 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

  17. Effect of hydrodynamic cavitation on zooplankton: A tool for disinfection

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Anil, A.C.; Venkat, K.; Gaonkar, C.; Kolwalkar, J.; Khandeparker, L.; Desai, D.V.; Mahulkar, A.V.; Ranade, V.V.; Pandit, A.B.

    . Experimental results indicated that cavitation and/or turbulent fluid shear dominantly originating from cavitation are effective tools for sea water disinfection as more than 80% of the zooplankton present in the sea water were killed. It was also observed...

  18. 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...

  19. 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...

  20. 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 (pEnvironmental Protection Agency to determine if restoration efforts have been effective in removing the plankton BUI and to monitor future conditions in the AOC.

  1. 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......-scale patterns in phytoplankton biogeography over nutrient availability. Strongest differences in the realized niche centers were found between diatoms and coccolithophores. Diatoms (87 species) occur in habitats with significantly lower temperatures, light intensity and salinity, with deeper mixed layers...... 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...

  2. 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.

  3. Physical and biological control of protistan community composition, distribution and abundance in the seasonal ice zone of the Southern Ocean between 30 and 80°E

    Science.gov (United States)

    Davidson, Andrew T.; Scott, Fiona J.; Nash, Geraldine V.; Wright, Simon W.; Raymond, Ben

    2010-05-01

    Protists are critical components of the Antarctic marine ecosystem as they comprise most of the living carbon and are the base of the Antarctic food web. They are also key determinants of vertical carbon flux and mediate draw-down of atmospheric CO 2 by the ocean. The community composition, abundance and distribution of marine protists (phytoplankton and protozoa) was studied during the Baseline Research on Oceanography, Krill and the Environment-West (BROKE-West) survey, in the seasonal ice zone during the 2005-2006 austral summer between 30°E and 80°E. Light and electron microscopy were used to determine the protistan composition and abundance in samples obtained at 30 sites from surface waters and at 26 sites from the depth of the maximum in situ chlorophyll fluorescence (Chl max). Cluster analysis was used to identify 5 groups of sample sites at the surface and 5 at the Chl max that were of similar protist composition and abundance. The physical characteristics, taxonomic composition, indicator taxa, and taxonomic diversity were determined for each group. In the southwest, a bloom of colonial Phaeocystis antarctica dominated the protistan community composition and biomass amongst the receding ice, but this was replaced by the flagellate life stage/s of this haptophyte in waters to the north. In the southeast, a diatom bloom had the highest diversity of protist taxa observed during the survey and centric diatoms dominated the biomass. Outside these blooms, grazing by krill probably reduced the composition and abundance of large diatoms and autotrophic dinoflagellates in coastal to mid-inshore waters. Only in offshore waters did large diatoms and dinoflagellates increase in abundance and diversity, despite low concentrations of iron and silicate at many of these sites. This increase was probably due to reduced top-down control by krill and other large zooplankton. Large diatoms dominated in offshore waters, despite other coincident studies showing that the

  4. Predictors of elevational biodiversity gradients change from single taxa to the multi-taxa community level.

    Science.gov (United States)

    Peters, Marcell K; Hemp, Andreas; Appelhans, Tim; Behler, Christina; Classen, Alice; Detsch, Florian; Ensslin, Andreas; Ferger, Stefan W; Frederiksen, Sara B; Gebert, Friederike; Haas, Michael; Helbig-Bonitz, Maria; Hemp, Claudia; Kindeketa, William J; Mwangomo, Ephraim; Ngereza, Christine; Otte, Insa; Röder, Juliane; Rutten, Gemma; Schellenberger Costa, David; Tardanico, Joseph; Zancolli, Giulia; Deckert, Jürgen; Eardley, Connal D; Peters, Ralph S; Rödel, Mark-Oliver; Schleuning, Matthias; Ssymank, Axel; Kakengi, Victor; Zhang, Jie; Böhning-Gaese, Katrin; Brandl, Roland; Kalko, Elisabeth K V; Kleyer, Michael; Nauss, Thomas; Tschapka, Marco; Fischer, Markus; Steffan-Dewenter, Ingolf

    2016-12-22

    The factors determining gradients of biodiversity are a fundamental yet unresolved topic in ecology. While diversity gradients have been analysed for numerous single taxa, progress towards general explanatory models has been hampered by limitations in the phylogenetic coverage of past studies. By parallel sampling of 25 major plant and animal taxa along a 3.7 km elevational gradient on Mt. Kilimanjaro, we quantify cross-taxon consensus in diversity gradients and evaluate predictors of diversity from single taxa to a multi-taxa community level. While single taxa show complex distribution patterns and respond to different environmental factors, scaling up diversity to the community level leads to an unambiguous support for temperature as the main predictor of species richness in both plants and animals. Our findings illuminate the influence of taxonomic coverage for models of diversity gradients and point to the importance of temperature for diversification and species coexistence in plant and animal communities.

  5. The nutritional status of zooplankton in a tropical reservoir: effects of food quality and community structure

    Directory of Open Access Journals (Sweden)

    R. M. Pinto-Coelho

    Full Text Available The temporal variability of energetic reserves of zooplankton in the eutrophic Pampulha reservoir was investigated during two successive annual cycles. The effects of dominance of large filter-feeding cladocerans (Daphnia and the occurrence of massive blooms of the cyanobacteria Microcystis on the energetic reserves of zooplankton were tested. This study showed that phytoplankton composition has a greater effect on energetic reserves of zooplankton. Some associations between lipid levels and the specific composition of zooplankton were also found. This study also demonstrated that the elementary composition of phosphorus in zooplankton can be used as an estimator of the nutritional status of zooplankton.

  6. Estimating In Situ Zooplankton Non-Predation Mortality in an Oligo-Mesotrophic Lake from Sediment Trap Data: Caveats and Reality Check.

    Directory of Open Access Journals (Sweden)

    Olga P Dubovskaya

    Full Text Available Mortality is a main driver in zooplankton population biology but it is poorly constrained in models that describe zooplankton population dynamics, food web interactions and nutrient dynamics. Mortality due to non-predation factors is often ignored even though anecdotal evidence of non-predation mass mortality of zooplankton has been reported repeatedly. One way to estimate non-predation mortality rate is to measure the removal rate of carcasses, for which sinking is the primary removal mechanism especially in quiescent shallow water bodies.We used sediment traps to quantify in situ carcass sinking velocity and non-predation mortality rate on eight consecutive days in 2013 for the cladoceran Bosmina longirostris in the oligo-mesotrophic Lake Stechlin; the outcomes were compared against estimates derived from in vitro carcass sinking velocity measurements and an empirical model correcting in vitro sinking velocity for turbulence resuspension and microbial decomposition of carcasses. Our results show that the latter two approaches produced unrealistically high mortality rates of 0.58-1.04 d(-1, whereas the sediment trap approach, when used properly, yielded a mortality rate estimate of 0.015 d(-1, which is more consistent with concurrent population abundance data and comparable to physiological death rate from the literature.Zooplankton carcasses may be exposed to water column microbes for days before entering the benthos; therefore, non-predation mortality affects not only zooplankton population dynamics but also microbial and benthic food webs. This would be particularly important for carbon and nitrogen cycles in systems where recurring mid-summer decline of zooplankton population due to non-predation mortality is observed.

  7. 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.

  8. Zooplankton community dynamics in the N. Aegean front (E. Mediterranean in the winter spring period

    Directory of Open Access Journals (Sweden)

    I. SIOKOU

    2014-12-01

    Full Text Available Zooplankton community composition was studied in the North Aegean frontal area in the winter-spring period along a trophic gradient going from the less saline and cold modified Black Sea water to the high salinity and temperature waters of Levantine origin. Samples were collected at the upper 100 m of three stations positioned along this gradient by using three nets with different mesh sizes (45 μm, 200 μm and 500 μm. Τhe community composition (all sizes was differentiated along the gradient with smoother seasonal succession and higher diversity with increasing oligotrophy and salinity. The temporal variability of the community composition revealed significant changes in the January-April period as well as gradual decrease of diversity index values at the station positioned within the front.  The major characteristic at this station was the abrupt increment and dominance of Centropages typicus in April, especially within the layer occupied by the modified Black Sea water. Significant difference in the community composition between March and April was a common feature in the whole study area and for all zooplankton fractions, though not of the same strength. The inflow of the Black Sea water and the trophic gradient were found to be important factors for the observed temporal variability and its spatial differentiation, while changes in the phytoplankton and protozoa abundance and community composition could account for the seasonal succession in species dominance.

  9. Systematics and genetic structure of Ponderosae taxa (Pinaceae) inhabiting the mountain islands of the Southwest.

    Science.gov (United States)

    Rehfeldt, G E

    1999-05-01

    The systematics and genetic structure of taxa representing the Ponderosae subsection of genus Pinus were assessed for disjunct, isolated, and peripheral populations occupying the mountain islands of the Southwest. Wind-pollinated progenies of 290 trees were compared in common gardens according to ten variables reflecting allometric, needle, and phenologic characteristics of 2-yr-old trees. The tests also included populations of similar taxa from the Rocky Mountains to the north and the Sierra Madre to the south. Principal component and canonical discriminant analyses demonstrated that the taxa segregated into three distinct groups, one of which contained two subgroups. These groupings collectively accounted for all of the many and confusing taxonomic descriptions that exist for the Ponderosae of the southwest United States and northern Mexico. The results suggested that intertaxa hybrids or hybrid derivatives may have been segregating within the progenies of only three of the parental trees. Hybridization, therefore, appears to be infrequent and inconsequential to the interrelationships among taxa and to contemporary genetic structures of taxa. Univariate analyses showed that the three distinct groups displayed different genetic structures despite similarities in their geographic distributions. While genetic variation within populations of all groups was abundant, a group labeled "quinquefoliata" displayed little variation among populations; one labeled "engelmannii" had abundant interpopulation variation that was largely randomly distributed across the landscape; and in a group containing the subgroups called "scopulorum" and "taxon X," abundant interpopulation variability was arranged systematically along moderately steep clines. These disparate genetic structures showed no apparent effects of the isolated, disjunct, and peripheral conditions under which populations of these taxa exist.

  10. 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.

    comparison of average trace metal concentrations in zooplankton from the Bay of Bengal showed enrichment of Fe, Co, Ni, Cu, Zn, Cd, and Pb in coastal zooplankton may be related to metal absorption from primary producers, and differences in metal...

  11. Extracoelenteric zooplankton feeding is a key mechanism of nutrient acquisition for the scleractinian coral Galaxea fascicularis

    NARCIS (Netherlands)

    Wijgerde, T.H.M.; Diantari, R.; Lewaru, M.W.; Verreth, J.A.J.; Osinga, R.

    2011-01-01

    Internal and external feeding on zooplankton may provide scleractinian corals with important nutrients. However, the latter process has never been properly quantified. To quantify the dynamics of zooplankton capture, digestion and release for a scleractinian coral, we performed detailed video

  12. 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...

  13. 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...

  14. Zooplankton along the Tamil Nadu coast

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Saraswathy, M.

    Comorin area copepods and decapods were dominant. The dense swarm of the ostracod Cypridina dentata (34556/100 m3) off Tuticorin was a noteworthy feature. The fluctuations in numerical abundance and percentage composition of all the major planktonic groups...

  15. 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 ...

  16. Structure and biodiversity of zooplankton communities in freshwater habitats of a Vereda Wetland Region, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Olívia Penatti Pinese

    2015-09-01

    Full Text Available Abstract Aims: Vereda wetlands are among the most important aquatic habitats in Brazilian savannah (Cerrado because of their association with river springs and its relevancy for biodiversity conservation. This study aimed to determine and compare the biodiversity of zooplankton in vereda lakes, differentiated by the presence or absence of aquatic macrophytes at an environmental reserve in Uberlândia, Minas Geais, Southeastern Brazil. Zooplanctonic abundance patterns and their relation with environmental parameters were also discussed and presented through multivariate statistics. Methods Twelve samples were taken at water surface, at 15-day intervals in 2006. It was observed a total richness of 75 species, including 12 genera, 29 species and one sub-species as new records for Minas Gerais State. Results Rotifers were the predominant group and Lecanidae was the most diverse family. Among cladocerans, Chydoridae showed the greatest richness and Bosminidae the highest abundance. Few adult copepods were sampled in this study, but nauplii were very frequent. Cyclopidae was the most common family among copepods and there was no record of Calanoida. Conclusions The difference in composition among the studied lakes was remarkable. The lake with macrophytes showed the greatest richness but the lowest density, and the opposite situation occurred in the other lake. This can be explained by the fact that aquatic macrophytes, as primary producers, exert a bottom-up effect on zooplankton community, sustaining a high local diversity in contrast with a low numeric abundance of these microorganisms. Therefore, this pattern may have been created by the surround heterogeneity and, at the same time, by the reduction of available minerals of the system caused by macrophyte matter fixation. Many studies on zooplankton need to be developed in palm swamp communities in order to better comprehend the biological diversity and the energy balance in different habitats for

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

    DEFF Research Database (Denmark)

    Kenitz, Kasia; Visser, Andre; Mariani, Patrizio

    2017-01-01

    The seasonal forcing of pelagic communities invokes a succession of the dominant phytoplankton and zooplankton species. Here, we characterize the seasonal succession of the plankton traits and their interactions using observations and model simulations of the plankton community in the western...... acquisition and photosynthesis, it also depends on grazing which couples feeding and motility traits across trophic guilds. Despite interannual variations in the species dominating the protist plankton community, the seasonal trait distribution reveals robust and repeatable seasonal patterns, changing between...... 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...

  18. 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.

  19. 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.

  20. 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.

    higher than those recorded even 'j during zooplankton swarms from the northern Indian Ocean (2.5 to 4.8 ml.m", MADHUPRA TAP et ai., 1980). Offshore biomass was low rel ative to upwelled regions but generally higher than noted in other non... of India. Temora turbinata and Acrocalanus sp. have been reported to form swarms during upwelling sea son (HARIDAS et 0/., 1980). The stndy also showed that most ofthese copepoda have either poor abundances or are absent in inshore waters during other...

  1. Feeding ecology of pelagic fish species in the Gulf of Riga (Baltic Sea): the importance of changes in the zooplankton community.

    Science.gov (United States)

    Lankov, A; Ojaveer, H; Simm, M; Põllupüü, M; Möllmann, C

    2010-12-01

    The feeding ecology of four pelagic fish species was studied in relation to their prey availability in the Gulf of Riga (Baltic Sea) during the summer 1999-2006. The zooplankton community was dominated by the cladoceran Bosmina longispina, rotifers Keratella cochlearis and K. quadrata and the copepod Eurytemora affinis, with the highest interannual variability in abundance recorded for B. longispina. The last influenced the diet of adult sprat Sprattus sprattus, juvenile smelt Osmerus eperlanus and three-spined stickleback Gasterosteus aculeatus as these were strongly selecting for B. longispina. The fish feeding activity did not match the abundance dynamics of their preferred prey, suggesting that fishes may switch to consume other prey in case the preferred diet was limited. A considerable dietary overlap indicated high potential competition between pelagic fish species. While herring Clupea harengus membras and G. aculeatus were relying on very different food, the diets of young O. eperlanus and G. aculeatus were very similar. Interannual variability in zooplankton composition and abundance significantly affected the diet composition of fishes, but those changes were insufficient to exert a consistent influence upon fish feeding activity and total amounts of zooplankton consumed. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

  2. Distribution and antimicrobial susceptibility of Vibrio species associated with zooplankton in coastal area of Korea.

    Science.gov (United States)

    Yang, Ji Hye; Mok, Jong Soo; Jung, Yeoun Joong; Lee, Ka Jeong; Kwon, Ji Young; Park, Kunbawui; Moon, Seong Yong; Kwon, Soon Jae; Ryu, A Ra; Lee, Tea Seek

    2017-12-15

    Vibrio parahaemolyticus and V. vulnificus are the most common pathogens causing seafood-borne illnesses in Korea. This study determines the abundance and antimicrobial resistance of pathogenic Vibrio species in seawater and zooplankton samples from the Geoje Island coast in Korea, which is an important area for coastal fisheries, the fishing industry, and tourism. The two Vibrio species were detected more in mesozooplankton samples than in seawater samples. V. parahaemolyticus isolates showed greater resistance than those of V. vulnificus for antimicrobials. Of V. parahaemolyticus isolates, 93.3% exhibited resistance to three or more antimicrobial agents. Conversely, more than 80% of V. vulnificus isolates showed susceptibility to all antimicrobials examined, with the exception of rifampicin. Our findings show that strong antimicrobial resistance of V. parahaemolyticus in the surveyed area was exposed to conventionally used antibiotics, therefore necessitating proper surveillance programs for the monitoring of antimicrobial resistance patterns in seawater bodies and aquatic animals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 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.

  4. New Oppioidea taxa from Madagascar (Acari: Oribatida

    Directory of Open Access Journals (Sweden)

    Mahunka, S.

    2012-07-01

    Full Text Available Within the framework of the continuous survey of the Madagascan Oribatida Fauna some newly surveyed Oppioidea (Acari: Oribatida species are discussed. Altogether 15 species are listed of the recently studied, identified and described taxa originating from several sites of the island (Malagasy Republic. Seven species of them are new to science and some other known only from few localities. One species represents also a new genus, Interbelba gen. nov. Three species, Berniniella bicarinata (Paoli, 1908, Quadroppia circumita (Hammer, 1961 and Discosuctobelba variosetosa (Hammer, 1961are recorded from Madagascar for the first time. With 22 figures.

  5. Microbial Taxa Distribution Is Associated with Ecological Trophic Cascades along an Elevation Gradient

    Science.gov (United States)

    Yao, Fei; Yang, Shan; Wang, Zhirui; Wang, Xue; Ye, Ji; Wang, Xugao; DeBruyn, Jennifer M.; Feng, Xue; Jiang, Yong; Li, Hui

    2017-01-01

    The elevational pattern of soil microbial diversity along mountain slopes has received considerable interest over the last decade. An increasing amount of taxonomic data on soil microbial community composition along elevation gradients have been collected, however the trophic patterns and environmental drivers of elevational changes remain largely unclear. Here, we examined the distribution patterns of major soil bacterial and fungal taxa along the northern slope of Changbai Mountain, Northeast China, at five typical vegetation types located between 740 and 2,691 m above sea level. Elevational patterns of the relative abundance of specific microbial taxa could be partially explained by the oligotrophic-copiotrophic theory. Specifically, two dark-coniferous forests, located at mid-elevation sites, were considered to be oligotrophic habitats, with relatively higher soil C/N ratio and NH4+-N concentrations. As expected, oligotrophic microbial taxa, belonging to the bacterial phyla Acidobacteria and Gemmatimonadetes, and fungal phylum Basidiomycota, were predominant in the two dark-coniferous forests, exhibiting a mid-elevation maximum pattern. In contrast, the broad leaf-Korean pine mixed forest located at the foot of the mountain, Betula ermanii-dominated forest located below the tree line, and alpine tundra at the highest elevation were considered more copiotrophic habitats, characterized by higher substrate-induced-respiration rates and NO3--N concentrations. Microbial taxa considered to be so called copiotrophic members, such as bacterial phyla Proteobacteria and Actinobacteria, and fungal phylum Ascomycota, were relatively abundant in these locations, resulting in a mid-elevation minimum pattern. At finer taxonomic levels, the two most abundant proteobacterial classes, alpha- and beta-Proteobacteria, along with Acidobacteria Gp1, 2, 3, 15, and the Basidiomycotal class of Tremellomycetes were classified with the copiotrophic group. Gamma- and delta

  6. Microbial Taxa Distribution Is Associated with Ecological Trophic Cascades along an Elevation Gradient

    Directory of Open Access Journals (Sweden)

    Fei Yao

    2017-10-01

    Full Text Available The elevational pattern of soil microbial diversity along mountain slopes has received considerable interest over the last decade. An increasing amount of taxonomic data on soil microbial community composition along elevation gradients have been collected, however the trophic patterns and environmental drivers of elevational changes remain largely unclear. Here, we examined the distribution patterns of major soil bacterial and fungal taxa along the northern slope of Changbai Mountain, Northeast China, at five typical vegetation types located between 740 and 2,691 m above sea level. Elevational patterns of the relative abundance of specific microbial taxa could be partially explained by the oligotrophic-copiotrophic theory. Specifically, two dark-coniferous forests, located at mid-elevation sites, were considered to be oligotrophic habitats, with relatively higher soil C/N ratio and NH4+-N concentrations. As expected, oligotrophic microbial taxa, belonging to the bacterial phyla Acidobacteria and Gemmatimonadetes, and fungal phylum Basidiomycota, were predominant in the two dark-coniferous forests, exhibiting a mid-elevation maximum pattern. In contrast, the broad leaf-Korean pine mixed forest located at the foot of the mountain, Betula ermanii-dominated forest located below the tree line, and alpine tundra at the highest elevation were considered more copiotrophic habitats, characterized by higher substrate-induced-respiration rates and NO3--N concentrations. Microbial taxa considered to be so called copiotrophic members, such as bacterial phyla Proteobacteria and Actinobacteria, and fungal phylum Ascomycota, were relatively abundant in these locations, resulting in a mid-elevation minimum pattern. At finer taxonomic levels, the two most abundant proteobacterial classes, alpha- and beta-Proteobacteria, along with Acidobacteria Gp1, 2, 3, 15, and the Basidiomycotal class of Tremellomycetes were classified with the copiotrophic group. Gamma- and

  7. Zooplankton and micronecton class identifications and abundances from CORIOLIS from 19670613 to 19670614 (NODC Accession 7100148)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NODC accession is an analog publication from the French Office de la Recherche Scientifique et Technique Outre-Mer (ORSTOM) Centre de Noumea, Rapport No. 22,...

  8. 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.

  9. 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.

  10. Restoration impact of an uncontrolled phosphogypsum dump site on the seasonal distribution of abiotic variables, phytoplankton and zooplankton along the near shore of the south-western Mediterranean coast.

    Science.gov (United States)

    Rekik, Amira; Maalej, Sami; Ayadi, Habib; Aleya, Lotfi

    2013-06-01

    'In connection with the Taparura Project, we studied the distribution of phytoplankton and zooplankton communities in relation to environmental variables at 18 stations sampled during four coastal cruises conducted between October 2009 and July 2010 on the north coast of Sfax (Tunisia, western Mediterranean Sea). The inshore location was largely dominated by diatoms (66 %) represented essentially by members of the genera Navicula, Grammatophora, and Licmophora. Dinophyceae were numerically the second largest group and showed an enhanced species richness. Cyanobacteriae developed in association with an important proliferation of colonial Trichodesmium erythraeum, contributing 39.4 % of total phytoplankton abundances. The results suggest that phytoplankters are generally adapted to specific environmental conditions. Copepods were the most abundant zooplankton group (82 %) of total zooplankton. A total of 21 copepod species were identified in all stations, with an overwhelming abundance of Oithona similis in autumn and summer, Euterpina acutifrons in winter, and Oncaea conifera in spring. The phosphogypsum restoration had been acutely necessary allowing dominant zooplankton species to exploit a wide range of food resources including phytoplankton and thus improving water quality.

  11. 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

  12. 26 Assessment of Zooplankton Community Structure of the Bahir ...

    African Journals Online (AJOL)

    Choice-Academy

    colometrically using Palintest analytical kit. Vertical plankton hauls were made at each of the sample stations using a 55µm net and immediately fixed in 4% formaldehyde solution. Observation and identification of zooplankton to species level was done with an. Olympus model microscope and classification was with the aid ...

  13. 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.

  14. Zooplankton Responses to Thin Layers: Integrating Behavior and Physiology

    Science.gov (United States)

    2004-09-30

    Zooplankton Responses to Thin Layers: Integrating Behavior and Physiology Stephen M. Bollens Department of Biology, and Romberg Tiburon Center...Department of Biology, and Romberg Tiburon Center for Environmental Studies,,San Francisco State University,,1600 Holloway Avenue,San Francisco,,CA,94132

  15. 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

  16. Impact of physicochemical factors on zooplankton species richness ...

    African Journals Online (AJOL)

    thermometer, pH meter, Secchi disk, DO meter and EC/TDS meter respectively. Monthly sampling was conducted between January, 2009 and December, 2010. Result showed reduced zooplankton species richness between 2009 and 2010 of 33 spp. and 21 spp. respectively. Likewise there was observed reduction in ...

  17. Local and regional factors influencing zooplankton communities in ...

    African Journals Online (AJOL)

    Associations between zooplankton community structure and abiotic (temperature, dissolved oxygen, turbidity, nutriments) and biotic factors (chlorophyll a and phytoplankton community) were examined, in Kasseb Reservoir, northern Tunisia. Samples were taken bimonthly from July to December 2002 at 3 sampling stations ...

  18. Global biodiversity patterns of marine phytoplankton and zooplankton

    NARCIS (Netherlands)

    Huisman, J.; Irigoien, X.; Harris, R.P.

    2004-01-01

    Although the oceans cover 70% of the Earth's surface, our knowledge of biodiversity patterns in marine phytoplankton and zooplankton is very limited compared to that of the biodiversity of plants and herbivores in the terrestrial world. Here, we present biodiversity data for marine plankton

  19. 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 ...

  20. spatial and temporal variation of zooplanktonic fauna composition ...

    African Journals Online (AJOL)

    DR. AMIN

    Zooplankton Samples were collected using plankton net by vertical haul. Samples were put .... Jakara River serves as the main drain for built up areas along the way. ... net by vertical haul. Samples were put into labeled. 100mL bottle (APHA, 2005). Some samples were preserved by dropping 4% Formalin for identification.

  1. Zooplankton and diatoms of temporary and permanent freshwater ...

    African Journals Online (AJOL)

    This paper provides a description of the zooplankton and epiphytic diatom communities of permanent and temporary freshwater pans in the Mpumalanga Highveld region of South Africa. Few studies have investigated the biota of pans in this area, which is seriously threatened by mining and agricultural development.

  2. Zooplankton variability in polluted and unpolluted waters off Bombay

    Digital Repository Service at National Institute of Oceanography (India)

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

    especially during the low tide with peaks in October/November and March/April. Mean zooplankton dry weight at the different stations were 8.7 mg/100 m3 (Thana), 5.8 mg/100 m3 (Versova), 4.04 mg/100 m3 (Harbour) and 3.84 mg/100 m3 (Mahim). Eventhough...

  3. Survey of Zooplanktons and Macro-Invertebrates of Gbedikere Lake ...

    African Journals Online (AJOL)

    Zooplankton and macro-invertebrates samples were collected weekly from three sampling stations at the Gbedikere Lake, Bassa Local Government Area, Kogi state, Nigeria from July to September 2008. Prior to sampling, Temperature of surface water, Secchi disc transparency, pH and dissolved oxygen concentration were ...

  4. Zooplankton composition in Dharamtar creek adjoining Bombay harbour

    Digital Repository Service at National Institute of Oceanography (India)

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

    turnover of 29 ton C.km/2. A major share of the zooplankton community was contributEd. by copepods (71.9%), decapods (11.4%) and chaetognaths (8.3%). Copepod diversity was maximum in October. Three species of chaetognaths were found in the area and Sagitta...

  5. 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

  6. The impact of environmental variability on Atlantic mackerel Scomber scombrus larval abundance to the west of the British Isles

    DEFF Research Database (Denmark)

    Pitois, Sophie G.; Jansen, Teunis; Pinnegar, John

    2015-01-01

    The value of the Continuous Plankton Recorder (CPR) fish larvae dataset, with its extensive spatiotemporal coverage, has been recently demonstrated with studies on long-term changes over decadal scales in the abundance and distribution of fish larvae in relation to physical and biological factors...... abundances of zooplankton and the larger phytoplankton groups, to a system characterized by higher temperature, lower salinities, lower abundances of zooplankton and larger phytoplankton and higher abundances of the small phytoplankton species. Analysis revealed a very weak positive correlation between...... the Second principal component and mackerel larvae yearly abundance, attributed to the North Atlantic Oscillation (NAO). The results presented here are in broad accord with recent investigations that link climatic variability and dynamics of mackerel reproduction. However, the growing body of literature...

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

    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 Sobygaard, 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...

  13. 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

  14. Predation Rates of Zooplankton by Fish Quantified with a Novel Acoustic and Optic System

    Science.gov (United States)

    Genin, A.; Lindemann, Y.; Roberts, P. L.; Jaffe, J. S.

    2016-02-01

    Zooplanktivory by fish is a major trophic link in most marine food webs. Quantifying the rates of that predation remains a major challenge which has rarely been measured in situ. Here we used a novel high-frequency sonar and camera system, called ZOOPS-O, to measure the rate of zooplankton feeding and prey selectivity by coral-reef fishes in the Red Sea. The system's high resolution camera was used as a "ground truth", relating the density of photographed zooplankters to that obtained with the sonar in different ranges of target strengths. Copepods were dominant (>75%). Two ZOOPS_O systems were deployed in the coral reef, one up-current and the other down-current of a site-attached group consisting of hundreds of fishes, dominated by the Reef Anthias (Pseuanthiass squamipinnis). Predation rate by the whole group was most intense with a removal rate of up to 250 zooplankters s-1 per cross section of 1 m2 along the space occupied by the group. Predation rates dependent mostly on ambient prey density, with no apparent effect of current speed. The feeding was highly selective for larger targets. The use of acoustics combined with optical imaging for target validation is a very effective, non-intrusive method for quantifying zooplankton predation in the sea. The high abundance of zooplanktivorous fish in the coral reef together with the fact that most of the prey originated in the off-shore waters, indicate that the trophic link created by the fish is a major pathway for the import of allochthonous nutrients to the reef community.

  15. 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.

  16. Testing Relationships between Energy and Vertebrate Abundance

    International Nuclear Information System (INIS)

    Carbone, C.; Pettorelli, N.

    2010-01-01

    Understanding what drives variation in the abundance of organisms is fundamental to evolutionary ecology and wildlife management. Yet despite its importance, there is still great uncertainty about the main factors influencing variation in vertebrate abundance across taxa. We believe valuable knowledge and increased predictive power could be gained by taking into account both the intrinsic factors of species and the extrinsic factors related to environmental surroundings in the commonly cited RQ model, which provides a simple conceptual framework valid at both the interspecific and the intraspecific scales. Approaches comparing studies undertaken at different spatial and taxonomic scales could be key to our ability to better predict abundance, and thanks to the increased availability of population size data, global geographic datasets, and improved comparative methods, there might be unprecedented opportunities to (1) gain a greater understanding of vertebrate abundance patterns and (2) test existing theories on free-ranging animals.

  17. 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

  18. 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.

  19. Live and frozen freshwater zooplankton as alternative startfeeding diets for Atlantic salmon in trays

    OpenAIRE

    Holm, Jens Christian

    1985-01-01

    Six groups of Atlantic salmon (Salmo salar) fry were starfed with frozen Daphnia longispina, standard start food type EWOS or water with natural content of live zooplankton drained from the littoral zone in a coastal lake. In last five days, those fed live zooplankton were given additional food in the form of frozen Daphnia. Dry-fed groups were the only ones to have an overall weight gain but had the lowest activity. Fry fed live zooplankton had the highest activity but t...

  20. Diel Vertical Dynamics of Gelatinous Zooplankton (Cnidaria, Ctenophora and Thaliacea in a Subtropical Stratified Ecosystem (South Brazilian Bight.

    Directory of Open Access Journals (Sweden)

    Miodeli Nogueira Júnior

    Full Text Available The diel vertical dynamics of gelatinous zooplankton in physically stratified conditions over the 100-m isobath (~110 km offshore in the South Brazilian Bight (26°45'S; 47°33'W and the relationship to hydrography and food availability were analyzed by sampling every six hours over two consecutive days. Zooplankton samples were taken in three depth strata, following the vertical structure of the water column, with cold waters between 17 and 13.1°C, influenced by the South Atlantic Central Water (SACW in the lower layer (>70 m; warm (>20°C Tropical Water in the upper 40 m; and an intermediate thermocline with a deep chlorophyll-a maximum layer (0.3-0.6 mg m-3. Two distinct general patterns were observed, emphasizing the role of (i physical and (ii biological processes: (i a strong influence of the vertical stratification, with most zooplankton absent or little abundant in the lower layer. The influence of the cold SACW on the bottom layer apparently restricted the vertical occupation of most species, which typically inhabit epipelagic warm waters. Even among migratory species, only a few (Aglaura hemistoma, Abylopsis tetragona eudoxids, Beroe sp., Thalia democratica, Salpa fusiformis crossed the thermocline and reached the bottom layer. (ii A general tendency of partial migrations, with variable intensity depending on the different species and developmental stages; populations tended to be more widely distributed through the water column during daylight, and to become more aggregated in the upper layer during the night, which can be explained based on the idea of the "hunger-satiation hypothesis", maximizing feeding and minimizing the chances of being predated.

  1. Diel Vertical Dynamics of Gelatinous Zooplankton (Cnidaria, Ctenophora and Thaliacea) in a Subtropical Stratified Ecosystem (South Brazilian Bight).

    Science.gov (United States)

    Nogueira Júnior, Miodeli; Brandini, Frederico Pereira; Codina, Juan Carlos Ugaz

    2015-01-01

    The diel vertical dynamics of gelatinous zooplankton in physically stratified conditions over the 100-m isobath (~110 km offshore) in the South Brazilian Bight (26°45'S; 47°33'W) and the relationship to hydrography and food availability were analyzed by sampling every six hours over two consecutive days. Zooplankton samples were taken in three depth strata, following the vertical structure of the water column, with cold waters between 17 and 13.1°C, influenced by the South Atlantic Central Water (SACW) in the lower layer (>70 m); warm (>20°C) Tropical Water in the upper 40 m; and an intermediate thermocline with a deep chlorophyll-a maximum layer (0.3-0.6 mg m-3). Two distinct general patterns were observed, emphasizing the role of (i) physical and (ii) biological processes: (i) a strong influence of the vertical stratification, with most zooplankton absent or little abundant in the lower layer. The influence of the cold SACW on the bottom layer apparently restricted the vertical occupation of most species, which typically inhabit epipelagic warm waters. Even among migratory species, only a few (Aglaura hemistoma, Abylopsis tetragona eudoxids, Beroe sp., Thalia democratica, Salpa fusiformis) crossed the thermocline and reached the bottom layer. (ii) A general tendency of partial migrations, with variable intensity depending on the different species and developmental stages; populations tended to be more widely distributed through the water column during daylight, and to become more aggregated in the upper layer during the night, which can be explained based on the idea of the "hunger-satiation hypothesis", maximizing feeding and minimizing the chances of being predated.

  2. Zooplankton diversity analysis through single-gene sequencing of a community sample

    Directory of Open Access Journals (Sweden)

    Nishida Mutsumi

    2009-09-01

    Full Text Available Abstract Background Oceans cover more than 70% of the earth's surface and are critical for the homeostasis of the environment. Among the components of the ocean ecosystem, zooplankton play vital roles in energy and matter transfer through the system. Despite their importance, understanding of zooplankton biodiversity is limited because of their fragile nature, small body size, and the large number of species from various taxonomic phyla. Here we present the results of single-gene zooplankton community analysis using a method that determines a large number of mitochondrial COI gene sequences from a bulk zooplankton sample. This approach will enable us to estimate the species richness of almost the entire zooplankton community. Results A sample was collected from a depth of 721 m to the surface in the western equatorial Pacific off Pohnpei Island, Micronesia, with a plankton net equipped with a 2-m2 mouth opening. A total of 1,336 mitochondrial COI gene sequences were determined from the cDNA library made from the sample. From the determined sequences, the occurrence of 189 species of zooplankton was estimated. BLASTN search results showed high degrees of similarity (>98% between the query and database for 10 species, including holozooplankton and merozooplankton. Conclusion In conjunction with the Census of Marine Zooplankton and Barcode of Life projects, single-gene zooplankton community analysis will be a powerful tool for estimating the species richness of zooplankton communities.

  3. 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.

  4. 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

  5. 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,...

  6. Zooplankton data collected from zooplankton net casts in TOGA Area - Atlantic and Indian Ocean by GAVESHANI and other platforms from 01 March 1963 to 31 March 1965 (NODC Accession 9400163)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected from GAVESHANI and other platforms using zooplankton net casts in the TOGA Area - Atlantic and Indian Ocean. Data were collected from...

  7. 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.

  8. 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

  9. 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 (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 liquid fertilizers, while B. rubens and M. macrocopa had peak abundances of 480 and 12ind/mL, respectively under similar conditions.

  10. 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 ovoviviparity or egg clutches in vegetation, food preference for dead animals or living microinvertebrates, substrate preference for 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.

  11. Zooplankton data collected from THOMAS G. THOMPSON in Arabian Sea; 01 January 1995 to 15 September 1995 (NODC Accession 9800072)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Arabian Sea from THOMAS G. THOMPSON. Data were collected from 01 January 1995 to 15 September 1995 by...

  12. 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...

  13. Diversity, abundance and community structure of benthic macro- and megafauna on the Beaufort shelf and slope.

    Science.gov (United States)

    Nephin, Jessica; Juniper, S Kim; Archambault, Philippe

    2014-01-01

    Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009-2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf (megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station) dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness (α diversity) and β diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and β diversity was explained by confounding factors: location (east-west), sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and β diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal β diversity across the depth gradient.

  14. 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.

  15. Distribution of zooplankton biomass and potential metabolic activities across the northern Benguela upwelling system

    Science.gov (United States)

    Fernández-Urruzola, I.; Osma, N.; Packard, T. T.; Gómez, M.; Postel, L.

    2014-11-01

    The distribution of zooplankton biomass and potential metabolic rates, in terms of electron transport system (ETS) and glutamate dehydrogenase (GDH), were analyzed along a cross-shelf transect in waters off Namibia. The highly variable dynamics of upwelling filaments promoted short-term fluctuations in the zooplankton biomass and metabolism. Maximum values were characteristically found over the shelf-break, where zooplankton biomass as dry mass (DM) reached peaks of 64.5 mg m- 3 within the upper 200 m in late August. Two weeks later, the zooplankton-DM decreased by more than a third (19 mg DM m- 3). Zooplankton potential respiration and NH4+ excretion averaged 234 μmol O2 m- 3 d- 1 and 169 μmol NH4+ m- 3 d- 1 in the Namibian shelf, respectively. High protein-specific ETS activities even in the low-chlorophyll waters outside the filament suggested a shift into greater omnivory seaward. In this light, zooplankton elemental and isotopic compositions were used to investigate the pelagic food web interactions. They evidenced spatial changes in the carbon resource for zooplankton as well as changes in the form of nitrogen that fueled the biological production in aging advected waters. Overall, both aspects of zooplankton metabolism impacted the primary productivity at a level less than 10% under all the different oceanographic conditions.

  16. A new sensitive tracer for the determination of zooplankton grazing activity

    NARCIS (Netherlands)

    Kwint, R.L J; Kramer, K.J M

    A new tracer compound is presented for determining zooplankton grazing activity. The gut content in zooplankton is measured as beta-dimethylsulphoniopropionate (DMSP), which can be measured even in individual copepods. Species specific DMSP/Chl-a ratios allow applications in, for example, prey

  17. 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 ...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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.

    in zooplankton collected from all stations. Bioassay tests were carried out for evaluating the acute toxicity of Cu and Ni on selected groups of zooplankton. Cu was more toxic than Ni. Among the different organisms tested Sagitta, Lucifer, Ctenophores and Medusae...

  3. Dynamics of suprabenthos-zooplankton communities around the Balearic Islands (western Mediterranean): Influence of environmental variables and effects on the biological cycle of Aristeus antennatus

    Science.gov (United States)

    Cartes, J. E.; Madurell, T.; Fanelli, E.; López-Jurado, J. L.

    Dynamics of suprabenthos and zooplankton were analyzed in two areas located in the NW (off Sóller harbour) and S (off Cabrera Archipelago) of Mallorca (Balearic Islands, western Mediterranean) at depths ranging between 135-780 m. Four stations situated respectively at 150 m (shelf-slope break), and at bathyal depths of 350, 650 and 750 m were sampled at bi-monthly intervals during six cruises performed between August 2003 and June 2004. Suprabenthos showed maximum biomass in both areas from late spring to summer (April to August), while minimum biomass was found in autumn (September-November). Though variable, temporal dynamics of zooplankton showed peaks of biomass in late winter and summer (February and June), while minimals occurred in autumn (August-September) and, at bathyal depths, in April. Suprabenthos (abundance; MDS analyses) showed a sample aggregation as a function of depth (3 groups corresponding to the shelf-slope break, upper slope — over 350 m; and the middle, deeper part of the slope — over 650-750 m), without any separation of hauls by season. By contrast, zooplankton samples were separated by season and not by depth. There was evidence of three seasonal groups corresponding to summer (June 2004-August 2003), autumn-winter (September and November 2003, February 2004), and spring (April 2004), being especially well established off Sóller. In general, suprabenthos was significantly correlated with the sediment variables (e.g. total organic matter content (% OM), potential REDOX), whereas zooplankton was almost exclusively dependent on Chl a at the surface, which suggests two different food sources for suprabenthos and zooplankton. The increase of suprabenthos abundance in April-June was paralleled by a sharp increase ( ca. 2.8 times) in the %OM on sediment during the same period, coupled ca. 1-2 months of delay with the peak of surface Chl a recorded in February-March (from satellite imagery data). Suprabenthos biomass was also correlated with

  4. Distribution, abundance and diversity of macrozoobenthos in Aiba ...

    African Journals Online (AJOL)

    African Journal of Aquatic Science ... Spatial and seasonal variation in macrozoobenthic composition, abundance and diversity in Aiba Reservoir were investigated bimonthy between June 2004 and April 2005 using a van ... Generally, larger numbers of taxa were recorded during the dry season than in the wet season.

  5. On the dependence of speciation rates on species abundance and ...

    Indian Academy of Sciences (India)

    Unknown

    abundance largely determines the rate of generation of intraspecific endogenous genetic variation, the result obtained suggests that the latter rate is not a limiting factor for speciation. Furthermore, the observed approximate constancy of speciation rates in different taxa cannot be accounted for by assuming a neutral or ...

  6. 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.

  7. 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

  8. Symbiont acquisition as neoseme: origin of species and higher taxa

    Science.gov (United States)

    Bermudes, D.; Margulis, L.

    1987-01-01

    We examine the hypothesis that, in the origin of species and higher taxa of eukaryotes, symbiont acquisition followed by partner integration has been equivalent to neoseme appearance leading to speciation. The formation of stable symbiotic associations involves partner-surface recognition, behavioral and metabolic interaction, and, in some cases, gene product (RNA, protein) and genic (RNA, DNA) integration. This analysis is applied here to examples of neosemes that define specific taxa and to neosemes in plants, fungi, and animals that involve the appearance of new types of tissue. If this hypothesis is correct--if the origin of major genetic variation leading to speciation and even higher taxa may occur through symbiont acquisition and integration--then the analysis of "origins of species and higher taxa" becomes analogous to the study of microbial community ecology.

  9. 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.

  10. Under the Scope: Bringing Zooplankton Research into the K-12 Classroom

    Science.gov (United States)

    Cohen, J.; Petrone, C.; Wickline, A.

    2016-02-01

    Despite their small size, zooplankton are dynamic and engaging animals when viewed by researchers, teachers, and students alike. Recognizing this, we are working with K-12 teachers to develop web-based resources for using zooplankton in the classroom. This outreach effort is part of a Delaware Sea Grant-funded research project studying seasonal dynamics of zooplankton in Delaware Bay. The research team, in collaboration with a marine education specialist, initially created a website (www.underthescope.udel.edu) containing: background information on zooplankton and the research project, a magnification tool, an identification tool, and education modules that facilitate directed use of the website content and tools. Local teachers (elementary through high school) were then hosted for a workshop to engage in zooplankton sampling using methods employed in the research project, including zooplankton tows and semi-autonomous identification using a ZooScan imaging system. Teachers then explored the website, evaluating its design, content, and usability for their particular grade level. Specific suggestions from the evaluation were incorporated into the website, with additional implementation planned over the next year. This teacher- researcher partnership was successful in developing the digital resource itself, in building excitement and capacity among a cohort of teachers, and in establishing relationships among teachers and researchers to facilitate adding new dimensions to the collaboration. The latter will include zooplankton sampling by school groups, researcher optical scanning of samples with ZooScan, and subsequent student analysis and reporting on their data.

  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. 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.

  13. 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.

  14. Prediction of abundance of arthropods according to climate change scenario RCP 4.5 and 8.5 in South Korea

    Directory of Open Access Journals (Sweden)

    Cheol Min Lee

    2016-06-01

    Full Text Available Abundance and diversity of arthropods were projected according to climate warming in South Korea. The taxa highly linked with temperature were selected for the projection. The values of abundance and richness were estimated using the mean values of abundance and richness in each temperature range. Temperature changes were based on the RCP (Representative Concentration Pathway 4.5 and RCP 8.5, and the abundance and richness during two periods (2011 -2015, 2056 -2065 were projected. From these projected results, change of other common taxa (> 1% occurrence were qualitatively predicted (i.e., decrease or increase. The projections showed that 45 of a total of 73 taxa will increase, 6 will change a little and 24 will decrease: the number of taxa that were expected to increase was two times more than the number of taxa that were expected to decrease. However, the overall abundance and diversity of arthropods were expected to decline as the temperature rises.

  15. Simulation Modeling of Zooplankton and Benthos in Reservoirs: Documentation and Development of Model Constructs.

    Science.gov (United States)

    1980-03-01

    large green algae increased. 112. Anabaena affinis and A. flos- aguae were rarely consumed by the zooplankton and were unaffected by increased grazing...in grazing rate is virtually nonexistent, other evidence (primarily for 97 Ix 40 . 0 0 0 ’-0 m 0.- 0 a 0 E- o r 4C ~Q o0 0 R0.0 0 0 0 0 00C co bo N0...zooplankton feed on particles of 100 pm or less. Little quantitative data exist on the feeding of predatory zooplankton and virtually nothing suitable for

  16. 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...

  17. Identifying the microbial taxa that consistently respond to soil warming across time and space.

    Science.gov (United States)

    Oliverio, Angela M; Bradford, Mark A; Fierer, Noah

    2017-05-01

    Soil microbial communities are the key drivers of many terrestrial biogeochemical processes. However, we currently lack a generalizable understanding of how these soil communities will change in response to predicted increases in global temperatures and which microbial lineages will be most impacted. Here, using high-throughput marker gene sequencing of soils collected from 18 sites throughout North America included in a 100-day laboratory incubation experiment, we identified a core group of abundant and nearly ubiquitous soil microbes that shift in relative abundance with elevated soil temperatures. We then validated and narrowed our list of temperature-sensitive microbes by comparing the results from this laboratory experiment with data compiled from 210 soils representing multiple, independent global field studies sampled across spatial gradients with a wide range in mean annual temperatures. Our results reveal predictable and consistent responses to temperature for a core group of 189 ubiquitous soil bacterial and archaeal taxa, with these taxa exhibiting similar temperature responses across a broad range of soil types. These microbial 'bioindicators' are useful for understanding how soil microbial communities respond to warming and to discriminate between the direct and indirect effects of soil warming on microbial communities. Those taxa that were found to be sensitive to temperature represented a wide range of lineages and the direction of the temperature responses were not predictable from phylogeny alone, indicating that temperature responses are difficult to predict from simply describing soil microbial communities at broad taxonomic or phylogenetic levels of resolution. Together, these results lay the foundation for a more predictive understanding of how soil microbial communities respond to soil warming and how warming may ultimately lead to changes in soil biogeochemical processes. © 2016 John Wiley & Sons Ltd.

  18. Composition, abundance, distribution and seasonality of ...

    African Journals Online (AJOL)

    Site 1, closest to the mouth, typically supported the highest diversity of zooplankton. Patterns in zooplankton density and diversity resulted from the combined influence of salinity, temperature and fresh water inflow. Keywords: Copepoda, freshwater inflow, mesohaline, Mysidacea African Journal of Aquatic Science 2013, ...

  19. 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

  20. Distribution and abundance of fish larvae in the northern Ionian Sea (Eastern Mediterranean)

    Science.gov (United States)

    Granata, Antonia; Cubeta, Annaluce; Minutoli, Roberta; Bergamasco, Alessandro; Guglielmo, Letterio

    2011-09-01

    The purpose of this paper was to study the spatial distribution, abundance and composition of fish larvae in the northern Ionian Sea. Samples were collected to the 600 m depth with an electronic multinet BIONESS during the "INTERREG Italia-Grecia" oceanographic cruise carried out in March 2000 off the Apulian Italian coast. A total of 46 species of teleost early stages were collected, belonging to 38 genera and 22 families. Over 52% of the larvae identified were mesopelagic species, almost 27% were demersal and about 21% pelagic. A total of 307 myctophids, 69 clupeids and 61 gadid post-larvae dominated the community. Benthosema glaciale (mean 6.1 mm SL) was the most abundant species (21.6%), the most frequent in the samples (28.8%), and dominant in the whole study area (mean 1.4 ind/100 m3). Particular attention was given to the horizontal and vertical distribution and abundance of the three dominant post-larval species: Benthosema glaciale, Sprattus sprattus sprattus and Notoscopelus elongatus. The Pearson coefficient ( R = 0.734) showed a high correlation between total zooplankton and fish larval assemblages in terms of spatial distribution abundance values. Regarding the vertical distribution of fish larvae, Sorensen's index ( S = 0.69) showed that fish larvae and total zooplankton abundance peaks co-occurred along the water column.

  1. 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

    mortality associated with (1) feeding activity (ambush feeders vs. feeding-current vs. cruising feeders) and (2) mate-finding behavior (males vs. females). The copepods Oithona nana, O. davisae (ambush feeders), Temora longicornis (feeding-current feeder), and Centropages hamatus (cruising feeder) were used...... 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...

  2. Diversity, abundance and community structure of benthic macro- and megafauna on the Beaufort shelf and slope.

    Directory of Open Access Journals (Sweden)

    Jessica Nephin

    Full Text Available Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009-2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf (< 100 m where they tended to be sparse and the slope where they were relatively abundant. The macrofauna principally comprised polychaetes with nephtyid polychaetes dominant on the shelf and maldanid polychaetes (up to 92% in relative abundance/station dominant on the slope. The megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness (α diversity and β diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and β diversity was explained by confounding factors: location (east-west, sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and β diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal β diversity across the depth gradient.

  3. 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

  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.

    samples were also analysed for methyl mercury, copper, zinc, iron, manganese, cadmium, lead and nickel. The sediment in Minamata Bay still contained high mercury concentrations. The mercury levels in zooplankton suggested that the Minamata Bay where...

  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. 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,...

  7. Production of certain hydrolytic enzymes by psychrophilic bacteria from the Antarctic krill, zooplankton and seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.

    . Presence of different enzymes was examined from about 500 of these strains. Bacterial numbers were the highest in the krill gut samples; moderate on zooplankton surfaces and low in water and the ice samples. Pseudomonas, Vibrio, Chromobacterium, Aeromonas...

  8. 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...

  9. Zooplankton biomass and composition in the western Bay of Bengal during late sw monsoon

    Digital Repository Service at National Institute of Oceanography (India)

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

    Copepoda formed the predominant group except in the southern region where a swarm of pelagic tunicates reduced their contribution to only 19% of the total zooplankton count. Decapod larvae occurred in fairly large numbers all along the coastal...

  10. Preliminary studies on the association between zooplankton and the stramenopilan fungi, Aplanochytrids

    Digital Repository Service at National Institute of Oceanography (India)

    Damare, V.S.; Damare, S.R.; Ramanujam, P.; Meena, R.M.; Raghukumar, S.

    : [1] using fluorescently-labeled prey approach and [2] using internal transcribed spacerbased molecular probe and in situ hybridization approach. The aplanochytrid cells were detected in the guts as well as fecal pellets of the zooplankton, thus...

  11. 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.

  12. 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.

    and in the marine food chain is also attempted. The results have shown high concentrations of Cd and Pb in zooplankton collected from the East Coast as compared to the West Coast. Some inferences have been drawn...

  13. 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...

  14. 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.

    Zooplankton samples collected from north Arabian Sea during March 1992 were analysed for elemental (C,H,N) composition. Estimated carbon, hydrogen and nitrogen concentrations displayed variations among different groups but their ratios were nearly...

  15. Zooplankton of the lagoons of the Laccadives: diel patterns and emergence

    Digital Repository Service at National Institute of Oceanography (India)

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

    of epibenthic forms are much higher than those observed in traps. Densities of emerging plankton varied geographically. Most of the zooplankton organisms which contribute to the lagoon fauna are resident in the lagoons and rarely occurred in the surrounding sea....

  16. 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.

    and Acartia pacifica in the night collections are the first record from the Zuari Estuary. Variations in the incidence of the common zooplankton groups and their species over the diel and tidal cycles are discussed...

  17. 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.

    in the representation of common groups of zooplankton for the flood and ebb periods was distinct. Copepods and decapods sustained higher population during the ebb period. Group like chaetognaths and molluscs were caught in appreciable numbers during the flood period...

  18. 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

    Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global...... 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....

  19. 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....

  20. A powerful microbiome-based association test and a microbial taxa discovery framework for comprehensive association mapping.

    Science.gov (United States)

    Koh, Hyunwook; Blaser, Martin J; Li, Huilin

    2017-04-24

    The role of the microbiota in human health and disease has been increasingly studied, gathering momentum through the use of high-throughput technologies. Further identification of the roles of specific microbes is necessary to better understand the mechanisms involved in diseases related to microbiome perturbations. Here, we introduce a new microbiome-based group association testing method, optimal microbiome-based association test (OMiAT). OMiAT is a data-driven testing method which takes an optimal test throughout different tests from the sum of powered score tests (SPU) and microbiome regression-based kernel association test (MiRKAT). We illustrate that OMiAT efficiently discovers significant association signals arising from varying microbial abundances and different relative contributions from microbial abundance and phylogenetic information. We also propose a way to apply it to fine-mapping of diverse upper-level taxa at different taxonomic ranks (e.g., phylum, class, order, family, and genus), as well as the entire microbial community, within a newly introduced microbial taxa discovery framework, microbiome comprehensive association mapping (MiCAM). Our extensive simulations demonstrate that OMiAT is highly robust and powerful compared with other existing methods, while correctly controlling type I error rates. Our real data analyses also confirm that MiCAM is especially efficient for the assessment of upper-level taxa by integrating OMiAT as a group analytic method. OMiAT is attractive in practice due to the high complexity of microbiome data and the unknown true nature of the state. MiCAM also provides a hierarchical association map for numerous microbial taxa and can also be used as a guideline for further investigation on the roles of discovered taxa in human health and disease.

  1. 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)

  2. 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).

  3. Zooplankton-based assessment of the trophic state of a tropical forest river in Nigeria

    Directory of Open Access Journals (Sweden)

    Imoobe T.O.T.

    2009-01-01

    Full Text Available In this study, we explore the usefulness of zooplankton as a tool for assessing the trophic status of a Nigerian forest river. The river was sampled monthly and investigated for water physico-chemistry and zooplankton community structure using basic statistical measurement of diversity indices to characterize the zooplankton fauna. The trophic sta­tus of the river evaluated from its physico-chemical parameters indicates that the river is oligotrophic. The zooplankton composition was typical of a tropical freshwater river, with a total of 40 species, made up of 16 rotifers, 12 cladocerans, and 12 copepods and their developing stages in the following order of dominance: Rotifera > Cladocera > Cyclopoida > Calanoida. There were strong correlations between the lake's trophic status and its zooplankton communities. The zoo­plankton community was dominated by numerous species of rotifers and crustaceans, which are typical of oligotrophic to mesotrophic systems, such species including Conochilus dossuarius and Synchaeta longipes. However, the most dominant zooplankton species in West African freshwater ecosystems, viz., Keratella tropica, Keratella quadrata, Brachionus angularis, Trichocerca pusilla, Filinia longiseta, Pompholyx sulcata, and Proales sp., and others that are indicator species of high trophic levels, were not recorded in the river. The river is very clear and can be used for all manner of recreational activities.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Hydrodynamic control of mesozooplankton abundance and biomass in northern Svalbard waters (79-81°N)

    Science.gov (United States)

    Blachowiak-Samolyk, Katarzyna; Søreide, Janne E.; Kwasniewski, Slawek; Sundfjord, Arild; Hop, Haakon; Falk-Petersen, Stig; Nøst Hegseth, Else

    2008-10-01

    The spatial variation in mesozooplankton biomass, abundance and species composition in relation to oceanography was studied in different climatic regimes (warm Atlantic vs. cold Arctic) in northern Svalbard waters. Relationships between the zooplankton community and various environmental factors (salinity, temperature, sampling depth, bottom depth, sea-ice concentrations, algal biomass and bloom stage) were established using multivariate statistics. Our study demonstrated that variability in the physical environment around Svalbard had measurable effect on the pelagic ecosystem. Differences in bottom depth and temperature-salinity best explained more than 40% of the horizontal variability in mesozooplankton biomass (DM m -2) after adjusting for seasonal variability. Salinity and temperature also explained much (21% and 15%, respectively) of the variability in mesozooplankton vertical distribution (ind. m -3) in August. Algal bloom stage, chlorophyll- a biomass, and depth stratum accounted for additional 17% of the overall variability structuring vertical zooplankton distribution. Three main zooplankton communities were identified, including Atlantic species Fritillaria borealis, Oithona atlantica, Calanus finmarchicus, Themisto abyssorum and Aglantha digitale; Arctic species Calanus glacialis, Gammarus wilkitzkii, Mertensia ovum and Sagitta elegans; and deeper-water inhabitants Paraeuchaeta spp., Spinocalanus spp., Aetideopsis minor, Mormonilla minor, Scolecithricella minor, Gaetanus ( Gaidius) tenuispinus, Ostracoda, Scaphocalanus brevicornis and Triconia borealis. Zooplankton biomasses in Atlantic- and Arctic-dominated water masses were similar, but biological "hot-spots" were associated with Arctic communities.

  9. 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

  10. 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.

  11. Mammal taxa constituting potential coevolved reservoirs of filoviruses

    DEFF Research Database (Denmark)

    Peterson, A.Townsend; Papes, Monica; Carroll, Darin S.

    2007-01-01

    The virus family Filoviridae includes 2 genera, the Marburg viruses and the Ebola viruses. The ecology of the filoviruses is poorly known, and indeed their host relationships remain completely unknown. An earlier effort prioritized mammalian taxa as to their possible status as the long-term coevo...

  12. Florae Malesianae Precursores. XI. New taxa in Canarium

    NARCIS (Netherlands)

    Leenhouts, P.W.

    1955-01-01

    English diagnoses of the following new taxa will before long be published in Flora Malesiana, I, 5²; with the exception of C. pseudosumatranum, the Latin diagnoses are exclusively based on the typecollection. The abbreviations used are as follows: BS = Bureau of Science, Manila BW = Boswezen, Dutch

  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. 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.

  15. 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

  16. Efeito das variáveis abióticas e do fitoplâncton sobre a comunidade zooplanctônica em um reservatório do Nordeste brasileiro Abiotic variables and phytoplankton effects on zooplanktonic community from a reservoir in northeast Brazil

    Directory of Open Access Journals (Sweden)

    Ênio W. Dantas

    2009-06-01

    Full Text Available O zooplâncton do reservatório de Mundaú, Pernambuco, nordeste do Brasil foi estudado quanto a variabilidade temporal (entre os horários e períodos seco chuvoso e espacial (nas regiões pelágica e litorânea em diferentes profundidades correlacionando-as com as variáveis ambientais e com o fitoplâncton. Vinte e três táxons infragenéricos e cinco subgenéricos de zooplâncton foram encontrados. De forma geral, Rotifera foi o grupo dominante em todo o estudo. O fitoplâncton foi dominado pelas cianobactérias. No período seco, as variáveis físicas certamente controlaram o desenvolvimento do zooplâncton, favorecendo o estabelecimento de elevadas densidades algais. No período chuvoso, a correlação do zooplâncton com os níveis de nutrientes do sistema na região pelágica provavelmente conduziu a uma competição de recursos entre o fitoplâncton e o zooplâncton, controlando as densidades algais.Zooplankton from Mundaú reservoir, State of Pernambuco, northeast Brazil was studied concerning temporal (hours and seasonal period and spatial (pelagic and coastal regions in different depths variabilities, correlating them to the environmental variables and the phytoplankton. Twenty-three infrageneric and five subgeneric zooplankton taxa were observed. On the whole, Rotifera was the dominant group during this study, especially influenced by the oxygen concentrations. Phytoplankton was dominated by Cyanobacteria. On the dry period, physical variables certainly controlled the zooplankton's development, allowing elevated algal densities. On the rainy period, zooplankton correlation with the system's nutrients levels on pelagic region probably conduced to a resources competition between phytoplankton and zooplankton, controlling algal densities.

  17. OXYGEN ABUNDANCES IN CEPHEIDS

    Energy Technology Data Exchange (ETDEWEB)

    Luck, R. E.; Andrievsky, S. M. [Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215 (United States); Korotin, S. N.; Kovtyukh, V. V., E-mail: luck@fafnir.astr.cwru.edu, E-mail: serkor@skyline.od.ua, E-mail: val@deneb1.odessa.ua, E-mail: scan@deneb1.odessa.ua [Department of Astronomy and Astronomical Observatory, Odessa National University, Isaac Newton Institute of Chile, Odessa Branch, Shevchenko Park, 65014 Odessa (Ukraine)

    2013-07-01

    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. 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.

  19. Small zooplankton sensing their environment: feeding, mating, and predator avoidance

    Science.gov (United States)

    Nihongi, Ai

    2004-03-01

    Since zooplankton play a significant role at the base of the food web in aquatic environments, it is important to understand their feeding behaviors, mating behaviors, and predator avoidance. First, I will present the water flow regime of Daphnia. Using a high-speed video, I filmed how water with algae particles enters and leaves Daphnia, how the water flows within Daphnia and how the appendages of Daphnia work to produce the water flow. Second, I will discuss mate-searching behaviors of freshwater calanoid copepods and Daphnia. Male and female zooplankters have to encounter each other for successful mating in 3D environment. I have observed the behaviors of freshwater calanoid copepods from Lake Michigan. As a result, they showed different behaviors from other species studied. Likewise, I have observed differences in mate-searching behaviors of D. pulex and D. magna. Last, I will show the results of predator-prey interactions in D. pulex with kairomone, a chemical cue, from predatory fish using 3-D near infrared optical system. As experimental conditions, we used the following treatments: (a) no light/ no kairomone, (b) no light/ kairomone, (c) light/ no kairomone, and (d) light/ kairomone. While it appears that light and kairomone have an interactive effect on the swimming behaviors of Daphnia, light seems to be the most influential factor. The observed frequent spinning movements of D. pulex in a darkened tank with a predatory fish, fathead minnow (Pimephales promelas), were successful predator avoidance maneuvers.

  20. Diversity-dependent evolutionary rates in early Palaeozoic zooplankton.

    Science.gov (United States)

    Foote, Michael; Cooper, Roger A; Crampton, James S; Sadler, Peter M

    2018-02-28

    The extent to which biological diversity affects rates of diversification is central to understanding macroevolutionary dynamics, yet no consensus has emerged on the importance of diversity-dependence of evolutionary rates. Here, we analyse the species-level fossil record of early Palaeozoic graptoloids, documented with high temporal resolution, to test directly whether rates of diversification were influenced by levels of standing diversity within this major clade of marine zooplankton. To circumvent the statistical regression-to-the-mean artefact, whereby higher- and lower-than-average values of diversity tend to be followed by negative and positive diversification rates, we construct a non-parametric, empirically scaled, diversity-independent null model by randomizing the observed diversification rates with respect to time. Comparing observed correlations between diversity and diversification rate to those expected from this diversity-independent model, we find evidence for negative diversity-dependence, accounting for up to 12% of the variance in diversification rate, with maximal correlation at a temporal lag of approximately 1 Myr. Diversity-dependence persists throughout the Ordovician and Silurian, despite a major increase in the strength and frequency of extinction and speciation pulses in the Silurian. By contrast to some previous work, we find that diversity-dependence affects rates of speciation and extinction nearly equally on average, although subtle differences emerge when we compare the Ordovician and Silurian. © 2018 The Author(s).

  1. Dead zone or oasis in the open ocean? Zooplankton distribution and migration in low-oxygen modewater eddies

    Science.gov (United States)

    Hauss, Helena; Christiansen, Svenja; Schütte, Florian; Kiko, Rainer; Edvam Lima, Miryam; Rodrigues, Elizandro; Karstensen, Johannes; Löscher, Carolin R.; Körtzinger, Arne; Fiedler, Björn

    2016-04-01

    The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300-600 m depth. Here, oxygen concentrations rarely fall below 40 µmol O2 kg-1, but are expected to decline under future projections of global warming. The recent discovery of mesoscale eddies that harbour a shallow suboxic (ocean deoxygenation. In spring 2014, a detailed survey of a suboxic anticyclonic modewater eddy (ACME) was carried out near the Cape Verde Ocean Observatory (CVOO), combining acoustic and optical profiling methods with stratified multinet hauls and hydrography. The multinet data revealed that the eddy was characterized by an approximately 1.5-fold increase in total area-integrated zooplankton abundance. At nighttime, when a large proportion of acoustic scatterers is ascending into the upper 150 m, a drastic reduction in mean volume backscattering (Sv) at 75 kHz (shipboard acoustic Doppler current profiler, ADCP) within the shallow OMZ of the eddy was evident compared to the nighttime distribution outside the eddy. Acoustic scatterers avoided the depth range between approximately 85 to 120 m, where oxygen concentrations were lower than approximately 20 µmol O2 kg-1, indicating habitat compression to the oxygenated surface layer. This observation is confirmed by time series observations of a moored ADCP (upward looking, 300 kHz) during an ACME transit at the CVOO mooring in 2010. Nevertheless, part of the diurnal vertical migration (DVM) from the surface layer to the mesopelagic continued through the shallow OMZ. Based upon vertically stratified multinet hauls, Underwater Vision Profiler (UVP5) and ADCP data, four strategies followed by zooplankton in response to in response to the eddy OMZ have been identified: (i) shallow OMZ avoidance and compression at the surface (e.g. most calanoid copepods, euphausiids); (ii) migration to the shallow OMZ core during daytime, but paying O2 debt at the surface at nighttime (e.g. siphonophores

  2. Distance decay relationships in foliar fungal endophytes are driven by rare taxa.

    Science.gov (United States)

    Oono, Ryoko; Rasmussen, Anna; Lefèvre, Emilie

    2017-07-01

    Foliar fungal endophytes represent a diverse and species-rich plant microbiome. Their biogeography provides essential clues to their cryptic relationship with hosts and the environment in which they disperse. We present species composition, diversity, and dispersal patterns of endophytic fungi associated with needles of Pinus taeda trees across regional scales in the absence of strong environmental gradients as well as within individual trees. An empirical designation of rare and abundant taxa enlightens us on the structure of endophyte communities. We report multiple distance-decay patterns consistent with effects of dispersal limitation, largely driven by community changes in rare taxa, those taxonomic units that made up less than 0.31% of reads per sample on average. Distance-decay rates and community structure also depended on specific classes of fungi and were predominantly influenced by rare members of Dothideomycetes. Communities separated by urban areas also revealed stronger effects of distance on community similarity, confirming that host density and diversity plays an important role in symbiont biogeography, which may ultimately lead to a mosaic of functional diversity as well as rare species diversity across landscapes. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. 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...

  4. Changes in zooplankton community, and seston and zooplankton fatty acid profiles at the freshwater/saltwater interface of the Chowan River, North Carolina

    Directory of Open Access Journals (Sweden)

    Deborah A. Lichti

    2017-08-01

    Full Text Available The variability in zooplankton fatty acid composition may be an indicator of larval fish habitat quality as fatty acids are linked to fish larval growth and survival. We sampled an anadromous fish nursery, the Chowan River, during spring of 2013 in order to determine how the seston fatty acid composition varied in comparison with the zooplankton community composition and fatty acid composition during the period of anadromous larval fish residency. The seston fatty acid profiles showed no distinct pattern in relation to sampling time or location. The mesozooplankton community composition varied spatially and the fatty acid profiles were typical of freshwater species in April. The Chowan River experienced a saltwater intrusion event during May, which resulted in brackish water species dominating the zooplankton community and the fatty acid profile showed an increase in polyunsaturated fatty acids (PUFA, in particular eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. The saltwater intrusion event was followed by an influx of freshwater due to high precipitation levels in June. The zooplankton community composition once again became dominated by freshwater species and the fatty acid profiles shifted to reflect this change; however, EPA levels remained high, particularly in the lower river. We found correlations between the seston, microzooplankton and mesozooplankton fatty acid compositions. Salinity was the main factor correlated to the observed pattern in species composition, and fatty acid changes in the mesozooplankton. These data suggest that anadromous fish nursery habitat likely experiences considerable spatial variability in fatty acid profiles of zooplankton prey and that are correlated to seston community composition and hydrodynamic changes. Our results also suggest that sufficient prey density as well as a diverse fatty acid composition is present in the Chowan River to support larval fish production.

  5. 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

    of haul taken. Secondary production values were slightly higher for the vertical (av. 26.17 mg C m/2 d/1) than for the surface samples (av. 24.5 mg C m/2 d/1). Highest (47.83 mg C m/2 d/1) and lowest (14.97 mg C m/2 d/1) values were obtained at 20 and 5 m...

  6. 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

  7. 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.

  8. Factors that drive zooplankton diversity in Neo-Tropical Savannah shallow lakes

    Directory of Open Access Journals (Sweden)

    Claudia Padovesi-Fonseca

    2017-11-01

    Full Text Available Abstract Zooplankton is an important community in aquatic ecosystems due to its linkage between primary producers and secondary consumers also playing a key role in cycling of organic materials. Aim: Therefore, our objective was to evaluate the effects of physicochemical variables of the water on the diversity of zooplankton community in seven tropical shallow lakes of Brazilian savannah. Methods Zooplankton samples were taken using a bucket and filtered 200 L by a 64 µm-mesh-plankton-net, and preserved for subsequent identification. Water temperature, dissolved oxygen, pH, electrical conductivity, turbidity, chlorophyll-a, ammonium, nitrate, nitrite, total phosphorus, and soluble reactive phosphorus were measured. Results The turbidity (decreases the temperature, luminosity and the system productivity and ammonium (increases the toxicity values were the major factors responsible for structuring the zooplankton community. On the other hand, also nitrogen and phosphorus (increase the productivity are limiting in savannah lentic systems for the zooplankton. The higher α diversity was positively associated with aquatic macrophytes (increase of niches and refuge, whereas lakes with geographic proximity increase the similarity in species composition, decreasing the β diversity. Conclusions We conclude that the deterministic processes (niche theory, due to species have different ecological requirements, are different responses to environmental gradients and increase the diversity in heterogenic lentic systems.

  9. 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.

  10. 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...

  11. Zooplankton data collected from BUREVESTNIK and other platforms in White Sea; 28 October 1952 to 12 February 1958 (NODC Accession 9900004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in White Sea from BUREVESTNIK and other platforms. Data were collected from 28 October 1952 to 12...

  12. 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

  13. Zooplankton studies with special reference to krill Euphausia superba Dana from fishing area 58 of Indian Ocean sector in Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rathod, V.

    % of zooplankton catch. Swarms of krill and salps were observed during the study period (austral summer), which were the prime cause for high standing stock of zooplankton. The prevailing physicochemical parameters with rich food supply were important factors...

  14. 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...

  15. Multi-taxa approach shows consistent shifts in arthropod functional traits along grassland land-use intensity gradient.

    Science.gov (United States)

    Simons, Nadja K; Weisser, Wolfgang W; Gossner, Martin M

    2016-03-01

    Intensification of land use reduces biodiversity but may also shift the trait composition of communities. Understanding how land use affects single traits and community trait composition, helps to understand why some species are more affected by land use than others. Trait-based analyses are common for plants, but rare for arthropods. We collected literature-based traits for nearly 1000 insect and spider species to test how land- use intensity (including mowing, fertilization, and grazing) across 124 grasslands in three regions of Germany affects community-weighted mean traits across taxa and in single taxa. We additionally measured morphometric traits for more than 150 Heteroptera species and tested whether the weighted mean morphometric traits change with increasing land-use intensity. Community average body size decreased and community average dispersal ability increased from low to high land-use intensity. Furthermore, the relative abundance of herbivores and of specialists among herbivores decreased and the relative abundance of species using the herb layer increased with increasing land-use intensity. Community-weighted means of the morphometric traits in Heteroptera also changed from low to high land-use intensity toward longer and thinner shapes as well as longer appendices (legs, wings, and antenna). While changes in traits with increasing mowing and fertilization intensity were consistent with the combined land-use intensity, community average traits did often not change or with opposite direction under increasing grazing intensity. We conclude that high land-use intensity acts as an environmental filter selecting for on average smaller, more mobile, and less specialized species across taxa. Although trait collection across multiple arthropod taxa is laborious and needs clear trait definitions, it is essential for understanding the functional consequences of biodiversity loss due to land-use intensification.

  16. 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.

    August, 1983. In most of the samples, the dominant groups in the order of their numerical abundance were copepods, chaetognaths, foraminifera, ostracods and decapods. The study has revealed a pronounced diurnal vertical migration in almost all areas...

  17. Extinction, diversity and survivorship of taxa in the fossil record

    OpenAIRE

    Newman, M. E. J.; Sibani, Paolo

    1998-01-01

    Using data drawn from large-scale databases, a number of interesting trends in the fossil record have been observed in recent years. These include the average decline in extinction rates throughout the Phanerozoic, the average increase in standing diversity, correlations between rates of origination and extinction, and simple laws governing the form of survivorship curves and the distribution of the lifetimes of taxa. In this paper we derive a number of mathematical relationships between thes...

  18. 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.

  19. 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

  20. Are troglobitic taxa troglobiomorphic? A test using phylogenetic inference

    Directory of Open Access Journals (Sweden)

    Laure Desutter-Grandcolas

    1997-01-01

    Full Text Available Obligate cave dwelling organisms are frequently characterised by a peculiar morphological syndrome, named troglomorphosis or troglobiomorphosis. This hypothesis, which deals with the evolutionary influence of the subterranean environment on cave organisms is far from being universally accepted. Yet it has been adopted by many authors and is often included in the definitions of the current classification of cave taxa. In this paper I present a test of the troglobiomorphosis hypothesis, using the case study of the cricket clade Amphiacustae (Orthoptera, Grylloidea, Phalangopsidae. Such a test preliminarily requires that observations of the habitat of the taxa (achieved on present-day populations are clearly separated from hypotheses on the evolutionary transformations of cave taxa (troglobiomorphosis hypothesis s. str.. The evolutionary hypotheses on troglobite morphology are tested using phylogenetic inference, that is by parsimoniously mapping the states of several morphological characters (eye size, body colour, relative hindleg size onto the cladogram of the Amphiacustae. According to these phylogenetic analyses, the troglobiomorphosis hypothesis is corroborated by the patterns reconstructed for eye size and body coloration characters, but is refuted by the patterns built for hindleg size.

  1. Response of zooplankton to nutrient enrichment and fish in shallow lakes: a pan-European mesocosm experiment

    NARCIS (Netherlands)

    Vakkilainen, K.; Kairesalo, T.; Hietala, J.; Balayla, D.; Bécares, E.; van de Bund, W.; Van Donk, E.; Fernández-Aláez, M.; Gyllström, M.; Hansson, L-A.; Rosa Miracle, M.; Moss, B.; Romo, S.; Rueda, J.; Stephen, D.

    2004-01-01

    1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 1999 by carrying out parallel mesocosm experiments in six lakes across Europe. 2. Zooplankton community structure, biomass and responses to nutrient and fish manipulation showed geographical and

  2. 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...

  3. 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

  4. The effect of zooplankton on the dynamics and molecular composition ofcarbohydrates during an experimental algal bloom

    DEFF Research Database (Denmark)

    Kragh, J. T.; Søndergaard, M.; Borch, N. H.

    2006-01-01

    The accumulation and degradation of carbohydrates (aldoses) were investigated during diatom blooms in two mesocosms. The effects of macrozooplankton were explored by addition of zooplankton to one mesocosm (+Z). Aldoses accumulated at a steady rate of 4.9 µM C d-1 from day 9 in the mesocosm without...... zooplankton (-Z), while zooplankton induced an increased rate to 10.3 µM C d-1. The surplus of 14 µM dissolved combined carbohydrates (DCCHO) in the +Z mesocosm after 22 days was caused by higher concentrations of arabinose, galactose and rhamnose. The increase was 50, 25 and 25% respectively in the +Z...... the fraction of dissolved organic carbon (DOC) explained by aldoses decreased in the -Z mesocosm while it increased with the presence of grazers. In the +Z mesocosm, two new peaks appeared on the chromatograms and contributed about 4% to the total area of aldoses. It is hypothesised that these two peaks...

  5. Major and trace elements in zooplankton from the Northern Gulf of California during summer.

    Science.gov (United States)

    Rentería-Cano, Margarita Elena; Sánchez-Velasco, Laura; Shumilin, Evgueni; Lavín, Miguel F; Gómez-Gutiérrez, Jaime

    2011-09-01

    We report the distribution of major and trace element concentrations in epipelagic zooplankton collected in the Northern Gulf of California in August 2003. The Bray-Curtis index defined three element assemblages in zooplankton: (1) major metals, which included only two elements, Na (3.6-17.0%) and Ca (1.0-4.8%). Na had its highest concentrations in the shallow tidally mixed Upper Gulf, where high salinity, temperature, and zooplankton biomass (dominated by copepods) prevailed. Ca showed its highest concentrations south of Ballenas Channel, characterized by tidal mixing and convergence-induced upwelling, indicated by low sea-surface temperature, salinity, and zooplankton biomass; (2) Six biological essential elements, like Fe (80-9,100 mg kg(-1)) and Zn (20-2,570 mg kg(-1)), were detected in high concentrations in zooplankton collected near Guaymas Basin, which had high surface temperature and chlorophyll a concentrations. (3) Metals of terrigenous origin, such as Sc (0.01-1.4 mg kg(-1)) and Th (0.03-2.3 mg kg(-1)), and redox-sensitive metals, like Co (3-23.8 mg kg(-1)); this was the assemblage with the largest number of elements (15). Both types of elements of assemblage 3 had maximum concentrations in the cyclonic eddy that dominates the summer circulation in the Northern region. We concluded that sediment resuspension by tidal mixing in the Upper Gulf, upwelling south of Ballenas Channel, and the cyclonic eddy were key oceanographic features that affected the element concentrations of epipelagic zooplankton in the Northern Gulf of California. Oceanographic mechanisms such as these may contribute to element incorporation in marine organisms in other seas.

  6. Seasonal response of zooplankton to monsoonal reversals in the Arabian Sea

    Science.gov (United States)

    Smith, Sharon; Roman, Michael; Prusova, Irina; Wishner, Karen; Gowing, Marcia; Codispoti, L. A.; Barber, Richard; Marra, John; Flagg, Charles

    The US JGOFS Arabian Sea Process Study was designed to provide a seasonally and spatially resolved carbon budget for a basin exhibiting some of the highest and lowest concentrations of plant biomass in the world's ocean. During the US JGOFS Process Study in the Arabian Sea (September 1994-January 1996), the absolute maximum in biomass of epipelagic zooplankton in the entire study was observed during the Southwest Monsoon season inshore of the Findlater Jet in the area of upwelling. The greatest contrast between high and low biomass in the study area also was observed during the Southwest Monsoon, as was the strongest onshore-offshore gradient in biomass. Lowest biomass throughout the study was observed at the most offshore station (S15), outside the direct influence of the monsoon forcing. The greatest day/night contrasts in biomass were observed nearshore in all seasons, with nighttime biomass exceeding daytime in the Northeast Monsoon season, but daytime exceeding nighttime in the Southwest Monsoon season. The diel vertical migration patterns in general reversed between the monsoons at all stations in the southern part of the study area. Virtually, no diel vertical migration of zooplankton took place in any season at the station with strong, persistent subsurface suboxic conditions (N7), suggesting that these conditions suppress migration. Based on the distribution of biomass, we hypothesize that inshore of the Findlater Jet, zooplankton grazing on phytoplankton is the dominant pathway of carbon transformation during both monsoon seasons, whereas offshore the zooplankton feed primarily on microplankton or are carnivorous, conditions that result in reduction of the carbon flux mediated by the zooplankton. Predation by mesopelagic fish, primarily myctophids, may equal daily growth of zooplankton inshore of the Findlater Jet during all seasons. This suggests that the food web inshore of the Findlater Jet is well integrated, may have evolved during past periods of

  7. Impacts of invasive plants on resident animals across ecosystems, taxa, and feeding types: a global assessment.

    Science.gov (United States)

    Schirmel, Jens; Bundschuh, Mirco; Entling, Martin H; Kowarik, Ingo; Buchholz, Sascha

    2016-02-01

    As drivers of global change, biological invasions have fundamental ecological consequences. However, it remains unclear how invasive plant effects on resident animals vary across ecosystems, animal classes, and functional groups. We performed a comprehensive meta-analysis covering 198 field and laboratory studies reporting a total of 3624 observations of invasive plant effects on animals. Invasive plants had reducing (56%) or neutral (44%) effects on animal abundance, diversity, fitness, and ecosystem function across different ecosystems, animal classes, and feeding types while we could not find any increasing effect. Most importantly, we found that invasive plants reduced overall animal abundance, diversity and fitness. However, this significant overall effect was contingent on ecosystems, taxa, and feeding types of animals. Decreasing effects of invasive plants were most evident in riparian ecosystems, possibly because frequent disturbance facilitates more intense plant invasions compared to other ecosystem types. In accordance with their immediate reliance on plants for food, invasive plant effects were strongest on herbivores. Regarding taxonomic groups, birds and insects were most strongly affected. In insects, this may be explained by their high frequency of herbivory, while birds demonstrate that invasive plant effects can also cascade up to secondary consumers. Since data on impacts of invasive plants are rather limited for many animal groups in most ecosystems, we argue for overcoming gaps in knowledge and for a more differentiated discussion on effects of invasive plant on native fauna. © 2015 John Wiley & Sons Ltd.

  8. 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

  9. Three-dimensional Magnetic Resonance Imaging of fossils across taxa

    Directory of Open Access Journals (Sweden)

    D. Mietchen

    2008-01-01

    Full Text Available The frequency of life forms in the fossil record is largely determined by the extent to which they were mineralised at the time of their death. In addition to mineral structures, many fossils nonetheless contain detectable amounts of residual water or organic molecules, the analysis of which has become an integral part of current palaeontological research. The methods available for this sort of investigations, though, typically require dissolution or ionisation of the fossil sample or parts thereof, which is an issue with rare taxa and outstanding materials like pathological or type specimens. In such cases, non-destructive techniques could provide a valuable methodological alternative. While Computed Tomography has long been used to study palaeontological specimens, a number of complementary approaches have recently gained ground. These include Magnetic Resonance Imaging (MRI which had previously been employed to obtain three-dimensional images of pathological belemnites non-invasively on the basis of intrinsic contrast. The present study was undertaken to investigate whether 1H MRI can likewise provide anatomical information about non-pathological belemnites and specimens of other fossil taxa. To this end, three-dimensional MR image series were acquired from intact non-pathological invertebrate, vertebrate and plant fossils. At routine voxel resolutions in the range of several dozens to some hundreds of micrometers, these images reveal a host of anatomical details and thus highlight the potential of MR techniques to effectively complement existing methodological approaches for palaeontological investigations in a wide range of taxa. As for the origin of the MR signal, relaxation and diffusion measurements as well as 1H and 13C MR spectra acquired from a belemnite suggest intracrystalline water or hydroxyl groups, rather than organic residues.

  10. 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.

  11. Variability of essential oil content of Mentha L. taxa

    Directory of Open Access Journals (Sweden)

    Jarmila Neugebauerová

    2012-01-01

    Full Text Available Species of genus Mentha L. can be described like herbs with many possibilities to use in industry and pharmacology. The most important product is essential oil. For commercially cultivating of species Mentha L. is variability of essential oil content very important characteristic. Variability of essential oil yield of twelve different taxa were monitored for four years. Essential oils were obtained via hydro-distillation and expressed as ml/kg. The highest variability of essential oil content during monitored period showed sample Pulegium vulgare and the lowest variability of essential oil content showed Mentha spicata.

  12. New colporate pollen taxa from Neyveli lignite, South India

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; Misra, B.K. (Birbal Sahni Institute of Palaeobotany, Lucknow (India))

    1991-02-19

    Four new pollen genera: {ital Bacuspinulopollenites} {ital Cuddaloripollis}, {ital Scrobiculatricolporites}, {ital Tamilipollenites} and seven new species from the subsurface lignite samples of the Mine III area of the Neyveli Lignite Field are described. {ital Tricolporopilites} (Kar and Saxena) Kar 1985 is amended and three new species {ital T. uniformis}, {ital T. differentialis} and {ital T. tectatus} are assigned to it. These colporate angiospermous pollen taxa provide additional information on the palynofloral composition of the main lignite seam encountered in three boreholes. 19 refs., 5 figs.

  13. Distribution, Abundance and Assemblages

    African Journals Online (AJOL)

    E-mail: luis.silva@cd.ieo.es. Cephalopod Species in Mozambican Waters Caught in the. “Mozambique 0307” Survey: Distribution, Abundance and. Assemblages. Luis Silva1, Eduardo Balguerías2, Paula Santana Afonso3, Ignacio Sobrino1, Juan Gil1 and. Candelaria Burgos1. 1Instituto Español de Oceanografía Unidad de ...

  14. 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

  15. 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.

  16. Laticiferous taxa as a source of energy and hydrocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Marimuthu, S.; Subramanian, R.B.; Kothari, I.L.; Inamdar, J.A. (Sardar Patel Univ., Gujarat (India))

    Twenty-nine laticiferous taxa of Apocynaceae, Asclepiadaceae, and Sapotaceae were screened for suitability as alternative sources of renewable energy, rubber, and phytochemicals and to select the most promising ones for large-scale cultivation. Of these, Allamanda violacea (14.9% protein, 13.8% polyphenol, 8.6% oil, 3.2% hydrocarbon), Catharanthus roseus (15.4% protein, 10.4% polyphenol, 11.5% oil, 1.9% hydrocarbon), and Holarrhena antidysenterica (14.2% protein, 16.4% polyphenol, 5,4% oil, 4.8% hydrocarbon) of Apocynaceae; Asclepias curassavica (19.3% protein, 6.5% polyphenol, 3.9% oil, 2.0% hydrocarbon), Calotropis gigantea (18.5% protein, 6.8% polyphenol, 7.0% oil, 2.8% hydrocarbon) of Asclepiadaceae; Mimusops elengi (11.3% protein, 9.7% polyphenol, 7.2% oil, 4.0% hydrocarbon) of Sapotaceae show promising potential for future petrochemical plantations; of all these taxa, Holarrhena antidysenterica yielded an unusually high percentage (4.8%) of hydrocarbon fraction followed by Mimusops elengi (4.0%). NMR spectra confirmed the presence of cis-polyisoprene in all species studied except Nerium indicum (white-flowered var.). These data indicate that the majority of the species under investigation may be considered for large-scale cultivation as an alternative source of rubber, intermediate energy, and other phytochemicals.

  17. Mnemiopsis leidyi (Ctenophora) in Narragansett Bay, 1975-1979: Abundance, size composition and estimation of grazing

    Science.gov (United States)

    Deason, Ellen E.

    1982-08-01

    Surveys of the distribution, abundance and size of the ctenophore Mnemiopsis leidyi were carried out in Narragansett Bay, R.I. over a 5-year period, 1975-1979. Yearly variations were observed in time of initiation of the ctenophore increase and maximum abundance. Biomass maxima ranged from 0·2 to 3 g dry weight m -3 at Station 2 in lower Narragansett Bay while maximum abundance varied from 20 to 100 animals m -3. Ctenophores less than 1 cm in length generally composed up to 50% of the biomass and 95% of the numerical abundance during the peak of the M. leidyi pulse. During the 1978 maxima and the declining stages of the pulse each year, 100% of the population was composed of small animals. M. leidyi populations increased earlier, reached greater maximum abundances, and were more highly dominated by small animals in the upper bay than toward the mouth of the bay. The averageclearance rate of M. leidyi larvae feeding on A. tonsa at 22°C was 0·36 l mg -1 dry weight day -1, with apparent selection for nauplii relative to copepodites. Predation and excretion rates applied to ctenophore biomass estimated for Narragansett Bay indicated that M. leidyi excretion is minor but predation removed a bay-wide mean of 20% of the zooplankton standing stock daily during August of 1975 and 1976. Variation in M. leidyi predation at Station 2 was inversely related to mean zooplankton biomass during August and September, which increased 4-fold during the 5-year period.

  18. Regional differences in seasonal timing of rainfall discriminate between genetically distinct East African giraffe taxa.

    Directory of Open Access Journals (Sweden)

    Henri A Thomassen

    Full Text Available Masai (Giraffa tippelskirchi, Reticulated (G. reticulata and Rothschild's (G. camelopardalis giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1 isolation-by-distance; 2 physical barriers to dispersal; 3 general habitat differences resulting in habitat segregation; or 4 regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically

  19. Regional differences in seasonal timing of rainfall discriminate between genetically distinct East African giraffe taxa.

    Science.gov (United States)

    Thomassen, Henri A; Freedman, Adam H; Brown, David M; Buermann, Wolfgang; Jacobs, David K

    2013-01-01

    Masai (Giraffa tippelskirchi), Reticulated (G. reticulata) and Rothschild's (G. camelopardalis) giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1) isolation-by-distance; 2) physical barriers to dispersal; 3) general habitat differences resulting in habitat segregation; or 4) regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically dictated

  20. 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......, annual consumption of the different zooplankton groups by pelagic fish is estimated. The present study estimates higher consumption estimates than previous studies for the three species and suggests that fish might have a greater impact on the zooplankton community as foragers. This way, NEA mackerel...... of 53–85 M tonnes of copepods, 20–32 M tonnes of krill, 8–42 M tonnes of appendicularians and 0.2–1.2 M tonnes of fish, depending on the year. For NSS herring and NEA mackerel the main prey groups are calanoids and appendicularians, showing a peak in consumption during June and June–July, respectively...

  1. Dredged Material Evaluations: Review of Zooplankton Toxicity Test Methods for Marine Water Quality Evaluations

    Science.gov (United States)

    2016-09-01

    reduce interactive effects between food and contaminants of concern. PUBLISHED RESEARCH USING ALTERNATIVE ZOOPLANKTON: While a few standard test...accumulation of contaminants of concern into biological tissue (bioaccumulation tests) after sediment settles at the placement site. Technical...EMBRYOS: The American Society for Testing and Materials International (ASTM) has produced standardized toxicity tests for echinoderm (ASTM E1563-98

  2. The role of zooplankton in the feeding ecology of fish fry from some ...

    African Journals Online (AJOL)

    The role of zooplankton in the feeding ecology of fish fry from some southern African estuaries. A.K. Whitfield. Institute for Freshwater Studies, Rhodes University, Grahamstown. The stomach contents of more than 1000 fish fry ( < 30 mm. S.L.), comprising 11 species, were examined from the. ' Mhlanga and Swartvlei ...

  3. The interaction between cyanobacteria and zooplankton in a more eutrophic world

    NARCIS (Netherlands)

    Ger, Kemal Ali; Urrutia-Cordero, Pablo; Frost, Paul C.; Hansson, Lars Anders; Sarnelle, Orlando; Wilson, Alan E.; Lurling, Miguel

    2016-01-01

    As blooms of cyanobacteria expand and intensify in freshwater systems globally, there is increasing interest in their ecological effects. In addition to being public health hazards, cyanobacteria have long been considered a poor quality food for key zooplankton grazers that link phytoplankton to

  4. The interaction between cyanobacteria and zooplankton in a more eutrophic world

    NARCIS (Netherlands)

    Ger, K. A.; Urrutia-Cordero, P.; Frost, P. C.; Hansson, L. A.; Sarnelle, O.; Wilson, A. E.; Lurling, M.

    2016-01-01

    As blooms of cyanobacteria expand and intensify in freshwater systems globally, there is increasing interest in their ecological effects. In addition to being public health hazards, cyanobacteria have long been considered a poor quality food for key zooplankton grazers that link phytoplankton to

  5. Phytoplankton and zooplankton of some paddy-cum-prawn culture fields in and around Cochin

    Digital Repository Service at National Institute of Oceanography (India)

    Gopalakrishnan, T.C.; Devi, C.B.L.; Aravindakshan, P.N.; Nair, K.K.C.; Balasubramanian, T.; Kutty, M.K.

    and total absence of zooplankton in many samples at the station close to the effluent discharge site of a fertilizer factory in area 2 however suggests adverse effect of extreme concentrations of nutrients (N02, 539.0; N03, 312.5; PO4, 2195.0 and NH4, 3980...

  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. effect of lead on zooplankton dynamics in challawa river, kano state

    African Journals Online (AJOL)

    DR. AMINU

    2008-12-01

    Dec 1, 2008 ... ABSTRACT. Lead concentration was determined with the aid of Atomic Absorption Spectrophotometer while zooplankton were collected with the aid of plankton net and analysed microscopically to assess their diversity and density in the Challawa River at four selected sites on fortnight basis between.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. Biochemical composition of zooplankton of Bombay High (oil platform) area in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, K.L.; Wagh, A.B.

    Variations in the biochemical constituents and calorific values of zooplankton from an off-shore oil processing platform were estimated. Mean value of biomass was 0.35 ml.m/3 with relatively higher values during post-monsoon period. Copepods formed...

  14. 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.

    fraction was the major constituent in the proximate analyses. A average carbon content for the zooplankton in this area was 28.46%. C:N ratio varied from 3.87-10.24. Caloric value ranged from 2.117 to 3.317 kcal/g dry wt. Using the dry weight and mean value...

  15. 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

    .62, 4.95, 1.54, 0.43, 4.4 and 4.16 respectively on wet weight basis. A good correlation of caloric potential with protein and lipid indicated to a certain extent that protein and lipid act as metabolic reserves of the zooplankton in the area...

  16. 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...

  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.

    Trace metal contents in zooplankton samples were estimated as a part of Marine Research-Living Resource Programme (MRLR) programme at 24 stations to establish the importance of these metals in the Bay of Bengal. The average concentration of Fe, Co...

  18. 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

  19. 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.

  20. 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...

  1. 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.

    @@/day. The intensely polluted estuaries are characterised by wide fluctuations in zooplankton biomass during the ebb and flood periods. The flood conditions sustained 1.8 to 4.4 times higher biomass than the ebb conditions. Mean rates of secondary...

  2. 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

  3. Temporal changes in radiocesium contamination derived from the Fukushima Dai-ichi Nuclear Power Plant accident in oceanic zooplankton in the western North Pacific.

    Science.gov (United States)

    Kitamura, Minoru; Honda, Makio C; Hamajima, Yasunori; Kumamoto, Yuichiro; Aoyama, Michio; Kawakami, Hajime; Aono, Tatsuo; Fukuda, Miho; Mino, Yoshihisa

    2017-06-01

    We investigated temporal changes of the contamination of oceanic zooplankton with radiocesium ( 134 Cs and 137 Cs) derived from the Fukushima Dai-ichi Nuclear Power Plant accident one month to three years after the accident at subarctic and subtropical stations (1900 and 900-1000 km from the plant, respectively) in the western North Pacific. The maximum activity concentrations of 137 Cs in zooplankton were two orders of magnitude higher than the pre-accident level. In the first four months after the accident, the activity concentrations of radiocesium in subtropical zooplankton decreased rapidly, but no similar change was observed at the subarctic station. The radiocesium derived from atmospheric deposition rapidly decreased as a result of seawater mixing. Thus, most of the subtropical zooplankton (with short lifespans) that had taken up radiocesium just after the accident were probably replaced by newly hatched zooplankton within four months of the accident, whereas subarctic zooplankton (with long lifespans) that were highly contaminated with radiocesium were still alive four months after the accident. By the end of the study, 137 Cs activity concentrations in subtropical zooplankton were still high, whereas the activity concentrations in subarctic zooplankton had decreased to nearly the pre-accident level. The former concentrations were probably influenced by a secondary supply of radiocesium via advection of subtropical mode water that was highly contaminated with Fukushima-derived radiocesium. Unexpectedly, at the subarctic station, the radiocesium activity concentrations in surface zooplankton were lower than those in subsurface zooplankton, whereas the opposite relationship was observed in surface and subsurface seawater. Because carnivores predominated in the subsurface zooplankton community, we hypothesize that the higher radiocesium activity concentrations in subsurface zooplankton were influenced by bioaccumulation. We conclude that radiocesium activity

  4. 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.

  5. Assessment of Longitudinal Gradients in Nematode Communities in the Deep Northern Gulf of Mexico and Concordance with Benthic Taxa

    Directory of Open Access Journals (Sweden)

    Jyotsna Sharma

    2012-01-01

    Full Text Available Meiobenthic nematode assemblages were examined at 16 stations along two transects on the eastern and western boundaries of the deep northern Gulf of Mexico (dNGOM at depths of 212–3000 m. The highest abundance (297 individuals 10 cm−2 and number of genera (71 occurred at stations near the Mississippi River delta. Number of genera decreased with increasing depth, and showed differences in community composition between the east and west regions. The dominant family, Comesomatidae, was represented by Sabatieria that was present at most shallow stations but absent at greater water depths. A significant difference in nematode feeding morphology was observed between depth groups but not between the two transects at different longitudes. Patterns of nematode community structure are congruent with harpacticoid copepods. Overall, the higher abundance and diversity of nematodes in the north-central Gulf of Mexico is consistent with findings of other benthic taxa and reflects organic material loading from the Mississippi River driving deep sea communities in the Gulf. The east-west gradient in composition of nematode communities suggests that nematode assemblages have well-defined distribution patterns similar to other meiobenthic taxa in the GOM but they are not aligned in the bathymetric zones observed in macrofauna, megafauna and demersal fishes.

  6. Global patterns of marine mammal, seabird, and sea turtle bycatch reveal taxa-specific and cumulative megafauna hotspots.

    Science.gov (United States)

    Lewison, Rebecca L; Crowder, Larry B; Wallace, Bryan P; Moore, Jeffrey E; Cox, Tara; Zydelis, Ramunas; McDonald, Sara; DiMatteo, Andrew; Dunn, Daniel C; Kot, Connie Y; Bjorkland, Rhema; Kelez, Shaleyla; Soykan, Candan; Stewart, Kelly R; Sims, Michelle; Boustany, Andre; Read, Andrew J; Halpin, Patrick; Nichols, W J; Safina, Carl

    2014-04-08

    Recent research on ocean health has found large predator abundance to be a key element of ocean condition. Fisheries can impact large predator abundance directly through targeted capture and indirectly through incidental capture of nontarget species or bycatch. However, measures of the global nature of bycatch are lacking for air-breathing megafauna. We fill this knowledge gap and present a synoptic global assessment of the distribution and intensity of bycatch of seabirds, marine mammals, and sea turtles based on empirical data from the three most commonly used types of fishing gears worldwide. We identify taxa-specific hotspots of bycatch intensity and find evidence of cumulative impacts across fishing fleets and gears. This global map of bycatch illustrates where data are particularly scarce--in coastal and small-scale fisheries and ocean regions that support developed industrial fisheries and millions of small-scale fishers--and identifies fishing areas where, given the evidence of cumulative hotspots across gear and taxa, traditional species or gear-specific bycatch management and mitigation efforts may be necessary but not sufficient. Given the global distribution of bycatch and the mitigation success achieved by some fleets, the reduction of air-breathing megafauna bycatch is both an urgent and achievable conservation priority.

  7. Zooplankton biomass and indices of feeding and metabolism in island-generated eddies around Gran Canaria

    Science.gov (United States)

    Hernández-León, S.; Almeida, C.; Gómez, M.; Torres, S.; Montero, I.; Portillo-Hahnefeld, A.

    2001-08-01

    Zooplankton biomass and indices of grazing (gut fluorescence), respiration (electron transfer system, ETS), ammonia excretion (glutamate dehydrogenase, GDH) and growth (aspartate transcarbamylase, ATC) were studied around the island of Gran Canaria (Canary Islands) during the so-called "late winter bloom". Four size classes (100-200, 200-500, 500-1000 and >1000 μm) were studied to assess the contribution of each size fraction to the mesoscale plankton distribution around the island. Cyclonic and anticyclonic eddies were observed downstream the island transporting and entraining water rich in chlorophyll. Zooplankton biomass showed a high variability around the island but it was dramatically lower in the core of the cyclonic eddy induced by the island, probably due to the divergent effect produced by the physical structure. A filament of relatively cold-water was also found reaching the island from the upwelling area off northwest Africa. High zooplankton biomass was observed in association with the filament water and in the vicinity of the anticyclonic eddy shed by the island. Specific gut content showed higher values in the boundaries of the cyclonic structures, while ETS and GDH activities where higher windward of the island, in both the cyclonic and anticyclonic eddies depending on the size fraction considered. With the restrictions of using those indices, control of primary production by grazing was 11-22% and up to 41% of the calculated ingestion from the indices of metabolism and growth could be supported by nonpigmented food. Calculated excretion rates could support about 8% of primary production. The low impact of zooplankton on autotrophic production, the low values of the index of growth and the distribution of biomass in relation to the presence of eddies downstream of Gran Canaria suggest that accumulation was the causative mechanism for the presence of high zooplankton biomass leeward of the island.

  8. Bridging the gap between marine biogeochemical and fisheries sciences; configuring the zooplankton link

    Science.gov (United States)

    Mitra, Aditee; Castellani, Claudia; Gentleman, Wendy C.; Jónasdóttir, Sigrún H.; Flynn, Kevin J.; Bode, Antonio; Halsband, Claudia; Kuhn, Penelope; Licandro, Priscilla; Agersted, Mette D.; Calbet, Albert; Lindeque, Penelope K.; Koppelmann, Rolf; Møller, Eva F.; Gislason, Astthor; Nielsen, Torkel Gissel; St. John, Michael

    2014-12-01

    Exploring climate and anthropogenic impacts on marine ecosystems requires an understanding of how trophic components interact. However, integrative end-to-end ecosystem studies (experimental and/or modelling) are rare. Experimental investigations often concentrate on a particular group or individual species within a trophic level, while tropho-dynamic field studies typically employ either a bottom-up approach concentrating on the phytoplankton community or a top-down approach concentrating on the fish community. Likewise the emphasis within modelling studies is usually placed upon phytoplankton-dominated biogeochemistry or on aspects of fisheries regulation. In consequence the roles of zooplankton communities (protists and metazoans) linking phytoplankton and fish communities are typically under-represented if not (especially in fisheries models) ignored. Where represented in ecosystem models, zooplankton are usually incorporated in an extremely simplistic fashion, using empirical descriptions merging various interacting physiological functions governing zooplankton growth and development, and thence ignoring physiological feedback mechanisms. Here we demonstrate, within a modelled plankton food-web system, how trophic dynamics are sensitive to small changes in parameter values describing zooplankton vital rates and thus the importance of using appropriate zooplankton descriptors. Through a comprehensive review, we reveal the mismatch between empirical understanding and modelling activities identifying important issues that warrant further experimental and modelling investigation. These include: food selectivity, kinetics of prey consumption and interactions with assimilation and growth, form of voided material, mortality rates at different age-stages relative to prior nutrient history. In particular there is a need for dynamic data series in which predator and prey of known nutrient history are studied interacting under varied pH and temperature regimes.

  9. Rapid removal of plutonium from the oceanic surface layer by zooplankton faecal pellets

    International Nuclear Information System (INIS)

    Higgo, J.J.W.; Cherry, R.D.; Heyraud, M.; Fowler, S.W.

    1977-01-01

    In view of the possibility that increasing quantities of Pu may in due course be introduced into the marine environment, it is important to have a detailed knowledge of its oceanic behaviour. It has been suggested that algae and perhaps the phytoplanktonic mass may have an important role in determining the chemical and physical forms of Pu predominant in the ocean. The role of the zooplanktonic mass has not been investigated in detail, but it is known that for several elements zooplankton metabolism may be an important biological factor in the removal of elements from the surface layers of the ocean. The particular importance of zooplankton faecal pellets in this process has been stressed, and it has been found that M. norvegica is rich in the naturally-occurring α-emitter 210 Po when compared with whole organism levels. A study is here described for Pu, and it is reported that M. norvegica faecal pellets are relatively rich in Pu. It is suggested that zooplankton faecal pellet deposition might be an important vector in the vertical oceanic transport of this element. Experimental details are given and results are shown in tabular form. The implications of the high concentrations of Pu in faecal pellets are described, and rough estimates are made for the removal time of Pu from the upper mixed ocean layers by zooplankton pellets alone; the result is 3.6 years. It is suggested that faecal pellets may have a significant role in the removal of Pu from the surface layers of the sea. (U.K.)

  10. For creating an expert system of Lake Onega: optimization of monitoring the state of the ecosystem on zooplankton indicators

    Directory of Open Access Journals (Sweden)

    Kalinkina Nataliya Mikhailovna

    2017-03-01

    Full Text Available In Lake Onega zooplankton is considered as a convenient and reliable indicator of the state of the lake ecosystem. As a formal basis for the consolidation of the accumulated information on the biota of Lake Onega, it is proposed to create an expert system using zooplankton as a prototype of an intelligent computer environment on all biotic components. In this context, it is proposed to review the organization of monitoring the state of zooplankton to increase the number of samples taken and to expand the geography of sampling as well as to simplify and computerize the sample analysis.

  11. New light on names and naming of dark taxa

    Directory of Open Access Journals (Sweden)

    Martin Ryberg

    2018-02-01

    Full Text Available A growing proportion of fungal species and lineages are known only from sequence data and cannot be linked to any physical specimen or resolved taxonomic name. Such fungi are often referred to as “dark taxa” or “dark matter fungi”. As they lack a taxonomic identity in the form of a name, they are regularly ignored in many important contexts, for example in legalisation and species counts. It is therefore very urgent to find a system to also deal with these fungi. Here, issues relating to the taxonomy and nomenclature of dark taxa are discussed and a number of questions that the mycological community needs to consider before deciding on what system/s to implement are highlighted.

  12. Distribution of isoflavonoids in non-leguminous taxa - an update.

    Science.gov (United States)

    Mackova, Zuzana; Koblovska, Radka; Lapcik, Oldrich

    2006-05-01

    Common emphasis of the fact that isoflavonoids are characteristic metabolites of leguminous plants sometimes leads to overlooking that the presence of isoflavonoids has been reported in several dozen other families. The spectrum of isoflavonoid producing taxa includes the representatives of four classes of multicellular plants, namely the Bryopsida, the Pinopsida, the Magnoliopsida and the Liliopsida. A review, recently published by Reynaud et al. [Reynaud, J., Guilet D., Terreux R., Lussignol M., Walchshofer N., 2005. Isoflavonoids in non-leguminous families: an update. Nat. Prod. Rep. 22, 504-515], provided listing of 164 isoflavonoids altogether reported in 31 non-leguminous angiosperm families. In this contribution we complement the abovementioned inventory bringing the references on further 17 isoflavonoid producing families and on additional 49 isoflavonoids reported to occur in non-leguminous plants.

  13. 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.

  14. 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

  15. 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 <300m to the sewage outfall discharge allowed the success of this classical monitoring method in a temperate marine-coastal ecosystem with certain gradient of pollution. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. 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.

  17. 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.

    Incidents of blooms of phytoplankton, discolourations of coastal estuarine waters and swarms of zooplankton are regular features along the west coast of India These are generally concomitant with changes in the chemical properties of coastal waters...

  18. 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

  19. 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

  20. 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.

  1. Root isoflavonoids and hairy root transformation influence key bacterial taxa in the soybean rhizosphere.

    Science.gov (United States)

    White, Laura J; Ge, Xijin; Brözel, Volker S; Subramanian, Senthil

    2017-04-01

    Rhizodeposits play a key role in shaping rhizosphere microbial communities. In soybean, isoflavonoids are a key rhizodeposit component that aid in plant defense and enable symbiotic associations with rhizobia. However, it is uncertain if and how they influence rhizosphere microbial communities. Isoflavonoid biosynthesis was silenced via RNA interference of isoflavone synthase in soybean hairy root composite plants. Rhizosphere soil fractions tightly associated with roots were isolated, and PCR amplicons from 16S rRNA gene variable regions V1-V3 and V3-V5 from these fractions were sequenced using 454. The resulting data was resolved using MOTHUR and vegan to identify bacterial taxa and evaluate changes in rhizosphere bacterial communities. The soybean rhizosphere was enriched in Proteobacteria and Bacteroidetes, and had relatively lower levels of Actinobacteria and Acidobacteria compared with bulk soil. Isoflavonoids had a small effect on bacterial community structure, and in particular on the abundance of Xanthomonads and Comamonads. The effect of hairy root transformation on rhizosphere bacterial communities was largely similar to untransformed plant roots with approximately 74% of the bacterial families displaying similar colonization underscoring the suitability of this technique to evaluate the influence of plant roots on rhizosphere bacterial communities. However, hairy root transformation had notable influence on Sphingomonads and Acidobacteria. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. 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.

  3. Controlling Harmful Cyanobacteria: Taxa-Specific Responses of Cyanobacteria to Grazing by Large-Bodied Daphnia in a Biomanipulation Scenario.

    Directory of Open Access Journals (Sweden)

    Pablo Urrutia-Cordero

    Full Text Available Lake restoration practices based on reducing fish predation and promoting the dominance of large-bodied Daphnia grazers (i.e., biomanipulation have been the focus of much debate due to inconsistent success in suppressing harmful cyanobacterial blooms. While most studies have explored effects of large-bodied Daphnia on cyanobacterial growth at the community level and/or on few dominant species, predictions of such restoration practices demand further understanding on taxa-specific responses in diverse cyanobacterial communities. In order to address these questions, we conducted three grazing experiments during summer in a eutrophic lake where the natural phytoplankton community was exposed to an increasing gradient in biomass of the large-bodied Daphnia magna. This allowed evaluating taxa-specific responses of cyanobacteria to Daphnia grazing throughout the growing season in a desired biomanipulation scenario with limited fish predation. Total cyanobacterial and phytoplankton biomasses responded negatively to Daphnia grazing both in early and late summer, regardless of different cyanobacterial densities. Large-bodied Daphnia were capable of suppressing the abundance of Aphanizomenon, Dolichospermum, Microcystis and Planktothrix bloom-forming cyanobacteria. However, the growth of the filamentous Dolichospermum crassum was positively affected by grazing during a period when this cyanobacterium dominated the community. The eutrophic lake was subjected to biomanipulation since 2005 and nineteen years of lake monitoring data (1996-2014 revealed that reducing fish predation increased the mean abundance (50% and body-size (20% of Daphnia, as well as suppressed the total amount of nutrients and the growth of the dominant cyanobacterial taxa, Microcystis and Planktothrix. Altogether our results suggest that lake restoration practices solely based on grazer control by large-bodied Daphnia can be effective, but may not be sufficient to control the

  4. Temporal variability of vertical migration of zooplankton at deep-sea floor in the Amundsen Sea, Antarctica

    Science.gov (United States)

    Sul La, Hyoung; Ha, Ho Kyung; Kang, Chan Young; Wåhlin, Anna; Park, Jisoo; Lee, SangHoon; Shin, Hyoung Chul

    2014-05-01

    Vertical migration of zooplankton is ubiquitous behavior in marine plankton community. Observations on diel, seasonal, and interannual variation of zooplankton behavior can support the knowledge for understanding of marine ecosystems. However, daily and seasonal rhythms are little observed in the deep-sea with seasonally ice-covered water. We described the pattern of diel vertical distribution (DVM) above deep-sea floor in a seasonally ice-covered Amundsen Sea. Times series of acoustic backscatter was observed using a bottom-moored, upward-looking Acoustic Doppler current profiler (ADCP) in the depth of 250-550 m. Multi-frequency acoustic backscatter data (38 and 120 kHz, EK60) were collected to identify the composition of DVM between fish and zooplankton using a dB differencing technique. The seasonal vertical distribution of zooplankton was clearly governed by the seasonal phase of surface solar radiation (SSR) and sea ice condition (SIC), while water temperature did not affect on the DVM variation. The main depths of zooplankton were primarily distributed near 250 m with high SSR and low SIC period and found near bottom in the lowermost layers (>400 m) with low SSR and high SIC between mid-April and mid-November. The temporal variation of main depths of zooplankton was significantly correlated with both SSR and SIC (r = 0.87 and -0.70, respectively, pbiological pump.

  5. 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

  6. Comparing mechanisms of host manipulation across host and parasite taxa

    Science.gov (United States)

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  7. 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

  8. Distribution of Abundant and Active Planktonic Ciliates in Coastal and Slope Waters Off New England

    Directory of Open Access Journals (Sweden)

    Sarah J. Tucker

    2017-11-01

    Full Text Available Despite their important role of linking microbial and classic marine food webs, data on biogeographical patterns of microbial eukaryotic grazers are limited, and even fewer studies have used molecular tools to assess active (i.e., those expressing genes community members. Marine ciliate diversity is believed to be greatest at the chlorophyll maximum, where there is an abundance of autotrophic prey, and is often assumed to decline with depth. Here, we assess the abundant (DNA and active (RNA marine ciliate communities throughout the water column at two stations off the New England coast (Northwest Atlantic—a coastal station 43 km from shore (40 m depth and a slope station 135 km off shore (1,000 m. We analyze ciliate communities using a DNA fingerprinting technique, Denaturing Gradient Gel Electrophoresis (DGGE, which captures patterns of abundant community members. We compare estimates of ciliate communities from SSU-rDNA (abundant and SSU-rRNA (active and find complex patterns throughout the water column, including many active lineages below the photic zone. Our analyses reveal (1 a number of widely-distributed taxa that are both abundant and active; (2 considerable heterogeneity in patterns of presence/absence of taxa in offshore samples taken 50 m apart throughout the water column; and (3 three distinct ciliate assemblages based on position from shore and depth. Analysis of active (RNA taxa uncovers biodiversity hidden to traditional DNA-based approaches (e.g., clone library, rDNA amplicon studies.

  9. 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.

  10. Dynamical analysis of a toxin-producing phytoplankton-zooplankton model with refuge.

    Science.gov (United States)

    Li, Juan; Song, Yongzhong; Wan, Hui

    2017-04-01

    To study the impacts of toxin produced by phytoplankton and refuges provided for phytoplankton on phytoplankton-zooplankton interactions in lakes, we establish a simple phytoplankton-zooplankton system with Holling type II response function. The existence and stability of positive equilibria are discussed. Bifurcation analyses are given by using normal form theory which reveals reasonably the mechanisms and nonlinear dynamics of the effects of toxin and refuges, including Hopf bifurcation, Bogdanov-Takens bifurcation of co-dimension 2 and 3. Numerical simulations are carried out to intuitively support our analytical results and help to explain the observed biological behaviors. Our findings finally show that both phytoplankton refuge and toxin have a significant impact on the occurring and terminating of algal blooms in freshwater lakes.

  11. Microplastics Alter the Properties and Sinking Rates of Zooplankton Faecal Pellets.

    Science.gov (United States)

    Cole, Matthew; Lindeque, Penelope K; Fileman, Elaine; Clark, James; Lewis, Ceri; Halsband, Claudia; Galloway, Tamara S

    2016-03-15

    Plastic debris is a widespread contaminant, prevalent in aquatic ecosystems across the globe. Zooplankton readily ingest microscopic plastic (microplastic, microplastics on faecal pellet properties are currently unknown. Here we test the hypotheses that (1) faecal pellets are a vector for transport of microplastics, (2) polystyrene microplastics can alter the properties and sinking rates of zooplankton egests and, (3) faecal pellets can facilitate the transfer of plastics to coprophagous biota. Following exposure to 20.6 μm polystyrene microplastics (1000 microplastics mL(-1)) and natural prey (∼1650 algae mL(-1)) the copepod Calanus helgolandicus egested faecal pellets with significantly (P microplastics, encapsulated within egests of the copepod Centropages typicus, could be transferred to C. helgolandicus via coprophagy. Our results support the proposal that sinking faecal matter represents a mechanism by which floating plastics can be vertically transported away from surface waters.

  12. Bridging the gap between marine biogeochemical and fisheries sciences; configuring the zooplankton link

    DEFF Research Database (Denmark)

    Mitra, Aditee; Castellani, Claudia; Gentleman, Wendy

    2014-01-01

    plankton food-web system, how trophic dynamics are sensitive to small changes in parameter values describing zooplankton vital rates and thus the importance of using appropriate zooplankton descriptors. Through a comprehensive review, we reveal the mismatch between empirical understanding and modelling...... activities identifying important issues that warrant further experimental and modelling investigation. These include: food selectivity, kinetics of prey consumption and interactions with assimilation and growth, form of voided material, mortality rates at different age-stages relative to prior nutrient......Exploring climate and anthropogenic impacts on marine ecosystems requires an understanding of how trophic components interact. However, integrative end-to-end ecosystem studies (experimental and/or modelling) are rare. Experimental investigations often concentrate on a particular group...

  13. Rotenone Decreases Hatching Success in Brine Shrimp Embryos by Blocking Development: Implications for Zooplankton Egg Banks.

    Directory of Open Access Journals (Sweden)

    Joseph A Covi

    Full Text Available While many zooplankton species recover quickly after the treatment of water resources with the piscicide, rotenone, some fail to reach pretreatment population density or, in rare cases, do not reappear at all. The variable impact of rotenone on zooplankton populations could stem from differences in the capacity of species to switch entirely to anaerobic catabolic pathways in the presence of rotenone, which blocks mitochondrial electron transport. Alternatively, variable responses among species could originate from differences in permeability of dormant life-stages to lipophilic chemicals like rotenone. The purpose of the present study was to determine the effects of rotenone on development, emergence and hatching of zooplankton embryos that lack both the anaerobic capacity to develop in the presence of rotenone and a permeability barrier to prevent the entry of rotenone during dormancy. Post-diapause embryos of the brine shrimp, Artemia franciscana, were employed as a model system, because they are permeable to lipophilic compounds when dechorionated and require aerobic conditions to support development. Early development in this species is also well characterized in the literature. Brine shrimp embryos were exposed to rotenone while development was either slowed by chilling or suspended by anoxia. Development, emergence and hatching were then observed in rotenone-free artificial seawater. The data presented demonstrate that rotenone freely diffuses across the embryonic cuticle in a matter of hours, and prevents development and emergence after brief exposures to ecologically relevant concentrations (0.025-0.5 mg L-1 of the piscicide. Neither the removal of rotenone from the environment, nor the removal of embryonic water with a hypertonic solution, are sufficient to reverse this block on development and emergence. These data indicate that rotenone could impair recruitment from egg banks for species of zooplankton that lack both an embryonic

  14. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    OpenAIRE

    KOZLOWSKY-SUZUKI, B.; BOZELLI, R. L.

    2002-01-01

    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. B...

  15. 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

  16. Towards developing a general framework for modelling vertical migration in zooplankton.

    Science.gov (United States)

    Morozov, Andrew Yu; Kuzenkov, Oleg A

    2016-09-21

    Diel vertical migration (DVM) of zooplankton is a widespread phenomenon in both oceans and lakes, and is generally considered to be the largest synchronized movement of biomass on Earth. Most existing mathematical models of DVM are based on the assumption that animals maximize a certain criterion such as the expected reproductive value, the venturous revenue, the ratio of energy gain/mortality or some predator avoidance function when choosing their instantaneous depth. The major shortcoming of this general point of view is that the predicted DVM may be strongly affected by a subjective choice of a particular optimization criterion. Here we argue that the optimal strategy of DVM can be unambiguously obtained as an outcome of selection in the underlying equations of genotype/traits frequency dynamics. Using this general paradigm, we explore the optimal strategy for the migration across different depths by zooplankton grazers throughout the day. To illustrate our ideas we consider four generic DVM models, each making different assumptions on the population dynamics of zooplankton, and demonstrate that in each model we need to maximize a particular functional to find the optimal strategy. Surprisingly, patterns of DVM obtained for different models greatly differ in terms of their parameters dependence. We then show that the infinite dimensional trait space of different zooplankton trajectories can be projected onto a low dimensional space of generalized parameters and the genotype evolution dynamics can be easily followed using this low-dimensional space. Using this space of generalized parameters we explore the influence of mutagenesis on evolution of DVM, and we show that strong mutagenesis allows the coexistence of an infinitely large number of strategies whereas for weak mutagenesis the selection results in the extinction of most strategies, with the surviving strategies all staying close to the optimal strategy in the corresponding mutagenesis-free system

  17. 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.

  18. 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

  19. 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.

  20. 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...

  1. 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...

  2. Do the long-term changes in zooplankton biomass indicate changes in fish stock?

    Czech Academy of Sciences Publication Activity Database

    Hrbáček, Jaroslav; Brandl, Zdeněk; Straškraba, M.

    2003-01-01

    Roč. 504, - (2003), s. 203-213 ISSN 0018-8158. [Reservoir Limnology and Water Quality /4./. České Budějovice, 12.08.2002-16.08.2002] R&D Projects: GA ČR GA206/01/1113 Institutional research plan: CEZ:AV0Z6017912 Keywords : zooplankton biomass * long term changes * seasonal cycles Subject RIV: EG - Zoology Impact factor: 0.720, year: 2003

  3. 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...

  4. Production and zooplankton community structure in the lagoon and surrounding sea at Kavaratti atoll (Lakshadweep)

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    .6 degrees C, 35.7 x 10/3, ml.l/1 and 0.8, 1.5 and 3.6 mu g-at.l/1 respectively. Fluctuations in the secondary production were greater in the surrounding sea (19.9 to 44.8 mgC.m/2.d/1) than at lagoon (6.6 to 15.7 mgC.m/2 d/1). Zooplankton community structure...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.

    ). On the Dlher hand, fairly large databases are available on the distribution of many epipelagic (upper 200 m) zooplankton groups and species, and those on calanoid copepods were reviewed recently (Madhupratap and Haridas, 1986). The present paper gives..., oxygen and chlorophyll a (Chla). .. Samples from MCN were preserved in buffered 4% formaldehyde seawater solution. The total numbers of organisms belonging to various groups were counted. Aliquots of samples between 0 and 200 m and the entire sample below...

  6. Herbivore regulation of plant abundance in aquatic ecosystems.

    Science.gov (United States)

    Wood, Kevin A; O'Hare, Matthew T; McDonald, Claire; Searle, Kate R; Daunt, Francis; Stillman, Richard A

    2017-05-01

    Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant-herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore-plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with

  7. 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.

  8. 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

  9. Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows.

    Science.gov (United States)

    Adhikari, Deepak; Gemmell, Brad J; Hallberg, Michael P; Longmire, Ellen K; Buskey, Edward J

    2015-11-01

    We describe an automated, volumetric particle image velocimetry (PIV) and tracking method that measures time-resolved, 3D zooplankton trajectories and surrounding volumetric fluid velocity fields simultaneously and non-intrusively. The method is demonstrated for groups of copepods flowing past a wall-mounted cylinder. We show that copepods execute escape responses when subjected to a strain rate threshold upstream of a cylinder, but the same threshold range elicits no escape responses in the turbulent wake downstream. The method was also used to document the instantaneous slip velocity of zooplankton and the resulting differences in trajectory between zooplankton and non-inertial fluid particles in the unsteady wake flow, showing the method's capability to quantify drift for both passive and motile organisms in turbulent environments. Applications of the method extend to any group of organisms interacting with the surrounding fluid environment, where organism location, larger-scale eddies and smaller-scale fluid deformation rates can all be tracked and analyzed. © 2015. Published by The Company of Biologists Ltd.

  10. Zooplankton biodiversity and community structure vary along spatiotemporal environmental gradients in restored peridunal ponds

    Directory of Open Access Journals (Sweden)

    Maria Anton-Pardo

    2015-11-01

    Full Text Available Zooplankton assemblages in neighboring ponds can show important spatial and temporal heterogeneity. Disentangling the influence of regional versus local factors, and of deterministic versus stochastic processes has been recently highlighted in the context of the metacommunity theory. In this study, we determined patterns of temporal and spatial variation in zooplankton diversity along one hydrological year in restored ponds of different hydroperiod and age. The following hypotheses regarding the assembling of species over time were tested: i dispersal is not limited in our study system due to its small area and high exposure to dispersal vectors; ii community dissimilarity among ponds increases with restoration age due to an increase in environmental heterogeneity and stronger niche-based assemblages;and iii similarity increases with decreasing hydroperiod because hydroperiod is a strong selective force filtering out organisms with long life cycles. Our results confirmed dispersal as a homogenizing force and local factors as gaining importance with time of restoration. However, short hydroperiod ponds were highly dissimilar, maybe due to the environmental differences among these ponds, or to high stochasticity followed by priority effects under a weak selection pressure. By adding a temporal dimension to the study of zooplankton structuring, we could identify the first months after flooding as being crucial for species richness, especially in short hydroperiod ponds; and we detected differences in seasonal species richness related to hydroperiod and pond age.

  11. 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.

  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. 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.

  14. Sustaining salmonid populations: A caring understanding of naturalness of taxa

    Science.gov (United States)

    Nielsen, Jennifer L.; Regier, Henry A.; Knudsen, E. Eric

    2004-01-01

    Species of the family of Salmonidae occur naturally in Northern Hemisphere waters that remain clear and cool to cold in summer. For purposes of reproduction, salmonids generally behaviorally respond to the currents of streams and lakes in recently glaciated areas. For feeding and maturation, many larger species migrate into existing systems of large lakes, seas, and oceans. The subfamilies include Salmoninae, Coregoninae, and Thymallinae. In many locales and regions of the hemisphere, numerous species of these subfamilies evolved and self-organized into species flocks or taxocenes of bewildering complexity. For example, any individual species may play different or unique ecological roles in different taxocenes. The northern Pacific and Atlantic Ocean ecosystems, with their seas and tributaries, each contained a metacomplex of such taxocenes that, in their natural state some centuries ago, resembled each other but differed in many ways. Humans have valued all species of this family for subsistence, ceremonial, naturalist, gustatory, angling, and commercial reasons for centuries. Modern progressive humans (MPHs), whose industrial and commercial enterprises have gradually spread over this hemisphere in recent time, now affect aquatic ecosystems at all scales from local to global. These human effects mingle in complex ways that together induce uniquely natural salmonid taxocenes to disintegrate with the loss of species, including those groups least tolerant to human manipulations, but extending more recently to those taxa more adapted to anthropogenic change. As we leave the modern era, dominated by MPHs, will we find ways to live sustainably with salmonid taxocenes that still exhibit self-organizational integrity, or will only individual, isolated populations of salmonid species, derived from those most tolerant of MPHs, survive? To achieve future sustainability of salmonids, we suggest implementation of a search for intuitive knowledge based on faith in the wisdom of

  15. Understanding selection for long necks in different taxa.

    Science.gov (United States)

    Wilkinson, David M; Ruxton, Graeme D

    2012-08-01

    There has been recent discussion about the evolutionary pressures underlying the long necks of extant giraffes and extinct sauropod dinosaurs. Here we summarise these debates and place them in a wider taxonomic context. We consider the evolution of long necks across a wide range of (both living and extinct) taxa and ask whether there has been a common selective factor or whether each case has a separate explanation. We conclude that in most cases long necks can be explained in terms of foraging requirements, and that alternative explanations in terms of sexual selection, thermoregulation and predation pressure are not as well supported. Specifically, in giraffe, tortoises, and perhaps sauropods there is likely to have been selection for high browsing. It the last case there may also have been selection for reaching otherwise inaccessible aquatic plants or for increasing the energetic efficiency of low browsing. For camels, wading birds and ratites, original selection was likely for increased leg length, with correlated selection for a longer neck to allow feeding and drinking at or near substrate level. For fish-eating long-necked birds and plesiosaurs a small head at the end of a long neck allows fast acceleration of the mouth to allow capture of elusive prey. A swan's long neck allows access to benthic vegetation, for vultures the long neck allows reaching deep into a carcass. Geese may be an unusual case where anti-predator vigilance is important, but so may be energetically efficient low browsing. The one group for which we feel unable to draw firm conclusions are the pterosaurs, this is in keeping with the current uncertainty about the biology of this group. Despite foraging emerging as a dominant theme in selection for long necks, for almost every taxonomic group we have identified useful empirical work that would increase understanding of the selective costs and benefits of a long neck. © 2011 The Authors. Biological Reviews © 2011 Cambridge Philosophical

  16. 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

  17. 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.

  18. Interactions between benthic predators and zooplanktonic prey are affected by turbulent waves.

    Science.gov (United States)

    Robinson, H E; Finelli, C M; Koehl, M A R

    2013-11-01

    Predators capture prey in complex and variable environments. In the ocean, bottom-dwelling (benthic) organisms are subjected to water currents, waves, and turbulent eddies. For benthic predators that feed on small animals carried in the water (zooplankton), flow not only delivers prey, but can also shape predator-prey interactions. Benthic passive suspension feeders collect prey delivered by movement of ambient water onto capture-surfaces, whereas motile benthic predators, such as burrow-dwelling fish, dart out to catch passing zooplankton. How does the flow of ambient water affect these contrasting modes of predation by benthic zooplanktivores? We studied the effects of turbulent, wavy flow on the encounter, capture, and retention of motile zooplanktonic prey (copepods, Acartia spp.) by passive benthic suspension feeders (sea anemones, Anthopleura elegantissima). Predator-prey interactions were video-recorded in a wave-generating flume under two regimes of oscillating flow with different peak wave velocities and levels of turbulent kinetic energy ("weak" and "strong" waves). Rates of encounter (number of prey passing through a sea anemone's capture zone per time), capture (prey contacting and sticking to tentacles per time), and retention (prey retained on tentacles, without struggling free or washing off, per time) were measured at both strengths of waves. Strong waves enhanced encounter rates both for dead copepods and for actively swimming copepods, but there was so much variability in the behavior of the live prey that the effect of wave strength on encounter rates was not significant. Trapping efficiency (number of prey retained per number encountered) was the same in both flow regimes because, although fewer prey executed maneuvers to escape capture in strong waves, more of the captured prey was washed off the predators' tentacles. Although peak water velocities and turbulence of waves did not affect feeding rates of passive suspension-feeding sea anemones

  19. 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.

  20. 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.