WorldWideScience

Sample records for bight zooplankton responses

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

    OpenAIRE

    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 Wa...

  2. 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.

  3. 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. PMID:26637179

  4. Net phytoplankton and zooplankton in the New York Bight, January 1976 to February 1978, with comments on the effects of wind, Gulf Stream eddies, and slope water intrusions

    OpenAIRE

    Smith, Daniel E.; Jossi, Jack W.

    1984-01-01

    Results are given of monthly net phytoplankton and zooplankton sampling from a 10 m depth in shelf, slope, and Gulf Stream eddy water along a transect running southeastward from Ambrose Light, New York, in 1976, 1977, and early 1978. Plankton abundance and temperature at 10 m and sea surface salinity at each station are listed. The effects of atmospheric forcing and Gulf Stream eddies on plankton distribution and abundance arc discussed. The frequency of Gulf Stream eddy passage through the N...

  5. Zooplankton Responses In A Tropical System With Environmental Stress

    Directory of Open Access Journals (Sweden)

    Nelson Javier Aranguren Riaño

    2014-03-01

    Full Text Available Processes of environmental transformation that currently occur in the climatic change context generate changes in ecosystems and biological communities. ¿How populations respond to these stressors? ¿what effects could occur on taxonomic and ecological diversity? The taxonomic composition and structure of the zooplankton was analyzed with relationship to environmental changes in a tropical water reservoir located at 6º02`18``N and 73º29`16`` W. During four months, samples were taken weekly covering stations of low, medium, and high precipitation. A high degree of temporal variability was established, it associated with a short hydraulic retention time estimated at 8 days.  Nine species were collected, of which Keratella tropica tropica and Thermocyclops decipiens were the two most abundant and constant species. Found values of H’ diversity and S richness were considered low, corresponding to a little mature community associated with a fluctuating physical environment and supported by high variation coefficients of electrical conductivity and Sechhi disk transparency. Drastic variations on the system volume in short time lapses generate important changes in the physical expression of system with a direct effect on composition and structure of the zooplankton. In general, the response model of the zooplankton in the reservoir according to the statement by the intermediate disturbance hypothesis.  RESPUESTAS DEL ZOOPLANCTON EN UN SISTEMA TROPICAL CON ALTA TENSIÓN AMBIENTAL Los procesos de transformación ambiental que se dan en la actualidad, en un marco de cambio climático, generan modificaciones en los ecosistemas y comunidades biológicas, ¿Cómo responden las poblaciones a estos factores de tensión? ¿Qué efectos se darían sobre la diversidad taxonómica y ecológica? Se analizó la variación de la composición taxonómica y estructura del zooplancton en función de los cambios ambientales en un reservorio tropical ubicado a 6º

  6. Predicting zooplankton response to environmental changes in a temperate estuarine ecosystem

    OpenAIRE

    Marques, Sónia; Azeiteiro, Ulisses; Leandro, Sérgio; Queiroga, Henrique; Primo, Ana; Martinho, Filipe; Viegas, Ivan; Pardal, Miguel

    2008-01-01

    Abstract A novel strategy that allows to predict the responses of zooplanktonic species to environmental conditions in an estuarine temperate ecosystem (Mondego estuary) is presented. It uses 12 indicator species from the zooplanktonic Mondego database (102 species) that are common members of the different habitats, characterized by their specific hydrological conditions. Indicator-species analysis (ISA) was used to define and describe which species were typical of each of the five sampling ...

  7. [The role of zooplankton and micronektron in the cycling and remineralization of chemical materials in the Southern California Bight: Progress report, November 1985-June 1986

    International Nuclear Information System (INIS)

    A Progress Report on Grant FG05-85ER60340 has already been submitted to DOE, and is appended here. The appended report covers much of the work completed during the current contract period. Work on the just-completed May 1986 cruise samples is just beginning at the time of writing. Sediment traps deployed at two locations in Santa Monica Basin in October 1985 were recovered in February 1986. The traps have sequentially rotating cups set to collect material for 14 days each during the deployment period. We have finished radiochemical analyses on the sediment trap samples collected on the February 1986 Cruise. Pellet production rates for salps and euphausiids were reported earlier. The February cruise was principally a hydrographic and trap recovery cruise, and there was no time for pellet production rate experiments. Thus, all the February hauls are being analyzed to assess diel biomass estimates of selected size classes of zooplankton in the vicinity of the traps. 5 tabs

  8. 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 year-to-ye

  9. The Roles of Advection and In Situ Growth in Determining the Dynamics of Continental Shelf Zooplankton: High Frequency Measurements of Zooplankton Biomass Coupled with Measurements of Secondary Productivity in the Middle Atlantic Bight

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Sharon L.

    1999-03-26

    Evaluation of the role of continental margins in planetary carbon cycles can be approached in various ways, with the extremes being knowledge generated either by large-scale studies of a few basic characteristics of the carbon cycle of shelves worldwide (comparative approach) or by temporally intensive studies of a few sites selected to typify contrasting processes. Mechanisms of cross-shelf transfer, for example, are presently of great interest and within the US there are at least four differing continental shelf environments in which cross-shelf processes are driven by storms (southern Bering Sea, northeastern US), by jets and eddies (northern California coast), by freshwater runoff (Bering Sea, Gulf of Mexico), and by frontal meanders and filaments of the Gulf Stream (southeastern US). Because the type and magnitude of the physical forcing, and its variability on an annual scale, are fundamental to the response of the carbon cycle, investigation of each of these shelves would offer insight useful to predictive global understanding of the carbon cycle on continental shelves.

  10. 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.

  11. Chemical Response of the Toxic Dinoflagellate Karenia mikimotoi Against Grazing by Three Species of Zooplankton.

    Science.gov (United States)

    Dang, Lin-Xi; Li, Yue; Liu, Fei; Zhang, Yong; Yang, Wei-Dong; Li, Hong-Ye; Liu, Jie-Sheng

    2015-01-01

    We investigated the toxicity of Karenia mikimotoi toward three model grazers, the cladoceran Moina mongolica, the copepod Pseudodiaptomus annandalei, and the crustacean Artemia salina, and explored its chemical response upon zooplankton grazing. An induction experiment, where K. mikimotoi was exposed to grazers or waterborne cues from the mixed cultures revealed that K. mikimotoi might be toxic or nutritionally inadequate toward the three grazers. In general, direct exposure to the three grazers induced the production of hemolytic toxins and the synthesis of eicosapentaenoic acid (EPA). Both EPA and the hemolytic toxins from K. mikimotoi decreased the survival rate of the three grazers. In addition, the survival rates of M. mongolica, P. annandalei, and A. salina in the presence of induced K. mikimotoi that had previously been exposed to a certain grazer were lower than their counterparts caused by fresh K. mikimotoi, suggesting that exposure to some grazers might increase the toxicity of K. mikimotoi. The chemical response and associated increased resistance to further grazing suggested that K. mikimotoi could produce deterrents to protect against grazing by zooplankton and that the substances responsible might be hemolytic toxins and EPA. PMID:25523905

  12. Influence of spatial heterogeneity on the type of zooplankton functional response: A study based on field observations

    Science.gov (United States)

    Morozov, Andrew; Arashkevich, Elena; Reigstad, Marit; Falk-Petersen, Stig

    2008-10-01

    Mathematical models of plankton dynamics are sensitive to the choice of type of zooplankton functional response, i.e., to how the rate of intake of food varies with the food density. Conventionally, the conclusion on the actual type of functional response for a given zooplankton species is made based upon laboratory analysis on experimental feeding. In this paper, we show that such an approach can be too simplistic and misleading. Based on real ocean data obtained from three expeditions of R/V Jan Mayen in the Barents Sea in 2003-2005, we demonstrate that vertical heterogeneity in algal distribution as well as active vertical movement of herbivorous zooplankton can modify the type of trophic response completely. In particular, we found that the rate of average intake of algae by Calanus glacialis exhibits a Holling type III response, instead of Holling type I or II found previously in laboratory experiments. We argue that this conceptual discrepancy is due to the ability of the zooplankton to feed in layers with high algal density and to avoid depths with lower algal density. Since theoretical studies would predict enhancing in system stability in the case of Holling type III, our results may be of importance for understanding the main factors controlling plankton dynamics.

  13. 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 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.

  14. 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

  15. Zooplankton Responses to Low-Oxygen Condition upon a Shallow Oxygen Minimum Zone in the Upwelling Region off Chile

    Science.gov (United States)

    Hidalgo, P.; Escribano, R.

    2015-12-01

    A shallow oxygen minimum zone (OMZ) is a critical component in the coastal upwelling ecosystem off Chile. This OMZ causes oxygen-deficient water entering the photic layer and affecting plankton communities having low tolerance to hypoxia. Variable, and usually species-dependent, responses of zooplankton to hypoxia condition can be found. Most dominant species avoid hypoxia by restricting their vertical distribution, while others can temporarily enter and even spent part of their life cycle within the OMZ. Whatever the case, low-oxygen conditions appear to affect virtually all vital rates of zooplankton, such as mortality, fecundity, development and growth and metabolism, and early developmental stages seem more sensitive, with significant consequences for population and community dynamics. For most study cases, these effects are negative at individual and population levels. Observations and predictions upon increasing upwelling intensity over the last 20-30 years indicate a gradual shoaling of the OMZ, and so that an expected enhancement of these negative effects of hypoxia on the zooplankton community. Unknown processes of adaptation and community-structure adjustments are expected to take place with uncertain consequences for the food web of this highly productive eastern boundary current ecosystem.

  16. Distribution of planktonic cnidarians in response to South Atlantic Central Water intrusion in the South Brazilian Bight

    Science.gov (United States)

    Nogueira Júnior, Miodeli; Brandini, Frederico P.; Codina, Juan C. U.

    2014-10-01

    Five oceanographic cruises were made between November 2005 and June 2006, sampling a cross-shelf transect off the South Brazilian Bight (SBB; 26°46‧S) to follow the seasonal development of the South Atlantic Central Water (SACW) intrusion over the shelf and its influence on the assemblage of planktonic cnidarians. An onshore wind-driven bottom intrusion of the SACW was clearly perceptible, reaching the coast in January. From March onward, the SACW influence was gradually displaced seaward due to wind and tidal mixing. By late June the SACW influence was offshore and the inshore was dominated by low-salinity waters (20 mm in diameter) Solmaris corona were observed exclusively in cold waters, suggesting this medusa is a SACW indicator.

  17. Response patterns of phytoplankton growth to variations in resuspension in the German Bight revealed by daily MERIS data in 2003 and 2004

    Directory of Open Access Journals (Sweden)

    Jian Su

    2015-10-01

    Full Text Available Chlorophyll (chl a concentration in coastal seas exhibits variability on various spatial and temporal scales. Resuspension of particulate matter can somewhat limit algal growth, but can also enhance productivity because of the intrusion of nutrient-rich pore water from sediments or bottom water layers into the whole water column. This study investigates whether characteristic changes in net phytoplankton growth can be directly linked to resuspension events within the German Bight. Satellite-derived chl a were used to derive spatial patterns of net rates of chl a increase/decrease (NR in 2003 and 2004. Spatial correlations between NR and mean water column irradiance were analysed. High correlations in space and time were found in most areas of the German Bight (R2 > 0.4, suggesting a tight coupling between light availability and algal growth during spring. These correlations were reduced within a distinct zone in the transition between shallow coastal areas and deeper offshore waters. In summer and autumn, a mismatch was found between phytoplankton blooms (chl a > 6 mg m−3 and spring-tidal induced resuspension events as indicated by bottom velocity, suggesting that there is no phytoplankton resuspension during spring tides. It is instead proposed here that frequent and recurrent spring-tidal resuspension events enhance algal growth by supplying remineralized nutrients. This hypothesis is corroborated by a lag correlation analysis between resuspension events and in-situ measured nutrient concentrations. This study outlines seasonally different patterns in phytoplankton productivity in response to variations in resuspension, which can serve as a reference for modelling coastal ecosystem dynamics.

  18. Zooplankton Hydrodynamics

    DEFF Research Database (Denmark)

    Wadhwa, Navish

    , and offspring size for all pelagic marine life, from bacteria to whales. We also reviewed and developed theoretical arguments for the observed scaling laws and for the characteristic sizes at which transitions from one strategy to another take place. Based on our findings, we divided life in the ocean...... 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...... was not explained by the three point force model. We speculate that this is due to inertial effects in the flow, which seem to play an important role in the swimming of larger zooplankton. We also developed a simple model to mimic the dynamics of periodic swimming, which showed that non-linear drag terms are needed...

  19. North Atlantic summers have warmed more than winters since 1353, and the response of marine zooplankton

    Science.gov (United States)

    Kamenos, Nicholas A.

    2010-01-01

    Modeling and measurements show that Atlantic marine temperatures are rising; however, the low temporal resolution of models and restricted spatial resolution of measurements (i) mask regional details critical for determining the rate and extent of climate variability, and (ii) prevent robust determination of climatic impacts on marine ecosystems. To address both issues for the North East Atlantic, a fortnightly resolution marine climate record from 1353–2006 was constructed for shallow inshore waters and compared to changes in marine zooplankton abundance. For the first time summer marine temperatures are shown to have increased nearly twice as much as winter temperatures since 1353. Additional climatic instability began in 1700 characterized by ∼5–65 year climate oscillations that appear to be a recent phenomenon. Enhanced summer-specific warming reduced the abundance of the copepod Calanus finmarchicus, a key food item of cod, and led to significantly lower projected abundances by 2040 than at present. The faster increase of summer marine temperatures has implications for climate projections and affects abundance, and thus biomass, near the base of the marine food web with potentially significant feedback effects for marine food security. PMID:21148422

  20. Modelling the future biogeography of North Atlantic zooplankton communities in response to climate change

    KAUST Repository

    Villarino, E

    2015-07-02

    Advances in habitat and climate modelling allow us to reduce uncertainties of climate change impacts on species distribution. We evaluated the impacts of future climate change on community structure, diversity, distribution and phenology of 14 copepod species in the North Atlantic. We developed and validated habitat models for key zooplankton species using continuous plankton recorder (CPR) survey data collected at mid latitudes of the North Atlantic. Generalized additive models (GAMs) were applied to relate the occurrence of species to environmental variables. Models were projected to future (2080–2099) environmental conditions using coupled hydroclimatix–biogeochemical models under the Intergovernmental Panel on Climate Change (IPCC) A1B climate scenario, and compared to present (2001–2020) conditions. Our projections indicated that the copepod community is expected to respond substantially to climate change: a mean poleward latitudinal shift of 8.7 km per decade for the overall community with an important species range variation (–15 to 18 km per decade); the species seasonal peak is expected to occur 12–13 d earlier for Calanus finmarchicus and C. hyperboreus; and important changes in community structure are also expected (high species turnover of 43–79% south of the Oceanic Polar Front). The impacts of the change expected by the end of the century under IPCC global warming scenarios on copepods highlight poleward shifts, earlier seasonal peak and changes in biodiversity spatial patterns that might lead to alterations of the future North Atlantic pelagic ecosystem. Our model and projections are supported by a temporal validation undertaken using the North Atlantic climate regime shift that occurred in the 1980s: the habitat model built in the cold period (1970–1986) has been validated in the warm period (1987–2004).

  1. High evolutionary potential of marine zooplankton

    NARCIS (Netherlands)

    Peijnenburg, K.T.C.A.; Goetze, E.

    2013-01-01

    Open ocean zooplankton often have been viewed as slowly evolving species that have limited capacity to respond adaptively to changing ocean conditions. Hence, attention has focused on the ecological responses of zooplankton to current global change, including range shifts and changing phenology. Her

  2. UV radiation and freshwater zooplankton: damage, protection and recovery

    OpenAIRE

    Rautio, Milla; Tartarotti, Barbara

    2010-01-01

    While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiologi...

  3. Zooplankton and fisheries

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Zooplankton are considered as the chief index of utilization of aquatic biotope at the secondary trophic level. The intensity of zooplankton aggregation depends on their ability to counter dispersion, phytoplankton growth, grazing rates, predator...

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

    Science.gov (United States)

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

    2016-03-01

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

  5. Biological processes in the water column of the South Atlantic bight. Progress report, July 12--August 20, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhofer, G.A.; Dunstan, W.M.

    1977-02-01

    Preliminary results are reported from a study of the relationship between intrusions of phytoplankton, zooplankton, and particulate matter in the South Atlantic Bight off the coast of Georgia and Northeast Florida. The relationship between temperature, chlorophyll, and particle volume in bottom water from various locations was determined and the data were correlated with data on water mass movements. Samples were collected from a ship following a specified grid pattern.

  6. Responses of zooplankton in lufenuron-stressed experimental ditches in the presence or absence of uncontaminated refuges

    NARCIS (Netherlands)

    López-Mancisidor, P.; Brink, van den P.J.; Crum, S.J.H.; Maund, S.J.; Carbonell, G.; Brock, T.C.M.

    2008-01-01

    Outdoor experimental ditches were used to evaluate the influence of untreated refuges on the recovery of zooplankton communities following treatment with the fast-dissipating insecticide lufenuron. Each experimental ditch was divided into three sections of the same surface area. The treatments diffe

  7. Eutrophication-like response to climate warming: an analysis of Lago Maggiore (N. Italy zooplankton in contrasting years

    Directory of Open Access Journals (Sweden)

    Anna VISCONTI

    2008-08-01

    Full Text Available Global mean surface temperatures are increasing. All ecosystems are likely to be affected and there is much interest at present in predicting the effects. In freshwater environments, we expect to observe, among other things, effects similar to those observed under eutrophication, such as increases in zooplankton population density and biomass as a result of enhanced population growth rates. Lago Maggiore underwent rapid eutrophication during the 60s and 70s, with a return to oligotrophy during the 80s and the 90s. Thus, it provides a case study to test the hypothesized eutrophication-like effects of recent climate warming. More specifically, we compare zooplankton biomass and density during the exceptionally warm years of the recent oligotrophic phase with values during the non-warm years of oligotrophy, and during years of the mesotrophic phase. This permits an analysis of zooplankton biomass and density with respect to temperature increase compared with the effects of eutrophication. Zooplankton population density and biomass sharply increased in 2003, the warmest year of the last century, as a result of Cladocera, particularly Daphnia, attaining values typical of the mesotrophic phase. These values were exceptional compared to typical values and were strongly different from those attained during cooler years since re-oligotrophication. Mean annual values of zooplankton density and biomass recorded in 2003 were fully comparable to typical values during the mesotrophic period. This observation confirms the hypothesis of an overall eutrophication-like effect of climate warming. Seasonal trends, characterized by an earlier start of population growth, are consistent with the effects of an increase in water temperature, as observed in laboratory experiments on the reproductive and growth strategies of Daphnia.

  8. Transcriptome response to thermal stress in two key zooplankton species, Calanus finmarchicus and C. Glacialis

    DEFF Research Database (Denmark)

    Smolina, I.; Kollias, S.; Møller, Eva Friis;

    Copepods of the genus Calanus are key zooplankton species in subarctic and arctic marine food webs. As a response to ocean warming, a northward movement of warm-water Calanus species has been detected. A further northward shift of C. finmarchicus is predicted into arctic waters traditionally...... and C. glacialis from Greenland were subjected to heat stress (+5C and +10C) for 4 hours and 6 days. Total RNA was extracted from animals under the different experimental conditions and the transcriptome was sequenced on an Ion Torrent. Sequencing of transcriptome libraries ofC. finmarchicus and C....... glacialis resulted in 4,894,166 and 3,412,784 reads respectively. Difference in the thermal responses of the two species is linked to acclimatory potential to ocean warming and possible changes in the marine communities....

  9. Zooplankton body composition

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2013-01-01

    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...... 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 a...

  10. Microplastic ingestion by zooplankton.

    Science.gov (United States)

    Cole, Matthew; Lindeque, Pennie; Fileman, Elaine; Halsband, Claudia; Goodhead, Rhys; Moger, Julian; Galloway, Tamara S

    2013-06-18

    Small plastic detritus, termed "microplastics", are a widespread and ubiquitous contaminant of marine ecosystems across the globe. Ingestion of microplastics by marine biota, including mussels, worms, fish, and seabirds, has been widely reported, but despite their vital ecological role in marine food-webs, the impact of microplastics on zooplankton remains under-researched. Here, we show that microplastics are ingested by, and may impact upon, zooplankton. We used bioimaging techniques to document ingestion, egestion, and adherence of microplastics in a range of zooplankton common to the northeast Atlantic, and employed feeding rate studies to determine the impact of plastic detritus on algal ingestion rates in copepods. Using fluorescence and coherent anti-Stokes Raman scattering (CARS) microscopy we identified that thirteen zooplankton taxa had the capacity to ingest 1.7-30.6 μm polystyrene beads, with uptake varying by taxa, life-stage and bead-size. Post-ingestion, copepods egested faecal pellets laden with microplastics. We further observed microplastics adhered to the external carapace and appendages of exposed zooplankton. Exposure of the copepod Centropages typicus to natural assemblages of algae with and without microplastics showed that 7.3 μm microplastics (>4000 mL(-1)) significantly decreased algal feeding. Our findings imply that marine microplastic debris can negatively impact upon zooplankton function and health. PMID:23692270

  11. The complex influences of back-barrier deposition, substrate slope and underlying stratigraphy in barrier island response to sea-level rise: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, U.S.A.

    Science.gov (United States)

    Brenner, Owen T.; Moore, Laura J.; Murray, A. Brad

    2015-10-01

    To understand the relative importance of back barrier environment, substrate slope and underlying stratigraphy in determining barrier island response to RSLR (relative sea-level rise), we use a morphological-behavior model (GEOMBEST) to conduct a series of sensitivity experiments, based on late-Holocene hindcast simulations of an island in the U.S. mid-Atlantic Bight (Metompkin Island, VA) having both salt marsh and lagoonal back-barrier environments, and we draw comparisons between these results and future simulations (2000-2100 AD) of island response to RSLR. Sensitivity analyses indicate that, as a whole, the island is highly sensitive to factors that reduce overall sand availability (i.e., high sand-loss rates and substrates containing little sand). Results also indicate that for all predicted future RSLR scenarios tested, islands having high substrate sand proportions (if allowed to migrate freely) will likely remain subaerial for centuries because of sufficient substrate sand supply and elevation to assist in keeping islands above sea level. Simulation results also lead to basic insights regarding the interactions among substrate slope, back-barrier deposition and island migration rates. In contrast to previous studies, which suggest that changes in substrate slope directly affect the island migration trajectory, we find that-in the presence of back-barrier deposition-the connection between substrate slope and island behavior is modulated (i.e., variability in migration rates is dampened) by changes in back-barrier width. These interactions-which tend to produce changes in shoreface sand content-lead to a negative feedback when the back-barrier deposit contains less sand than the underlying layer, resulting in a stable back-barrier width. Alternatively, a positive feedback arises when the back-barrier deposit contains more sand than the underlying layer, resulting in either back-barrier disappearance or perpetual widening.

  12. Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part1: Wave climate variability and impacts on the longshore sediment transport

    NARCIS (Netherlands)

    Almar, R.; Kestenare, E.; Reyns, J.; Jouanno, J; Anthony, E.; Laibi, R.; Hemer, M.; Du Penhoat, Y.; Ranasinghe, R.W.M.R.J.

    2015-01-01

    The short, medium and long-term evolution of the sandy coastline of the Bight of Benin in the Gulf of Guinea, West Africa, has become a major regional focal point due to the rapid socio-economic development that is occurring in the region, including rapid urbanization and a sharp increase in harbor-

  13. Danger of zooplankton feeding

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Jiang, H.; Colin, S.P.

    2010-01-01

    Zooplankton feed in any of three ways: they generate a feeding current while hovering, cruise through the water or are ambush feeders. Each mode generates different hydrodynamic disturbances and hence exposes the grazers differently to mechanosensory predators. Ambush feeders sink slowly and ther...

  14. Effects of experimental eutrophization on zooplankton community

    Directory of Open Access Journals (Sweden)

    Ana Maria Alves de Medeiros

    2013-06-01

    Full Text Available AIMS: The present study evaluated the role that increased nutrient concentrations play on zooplankton community, by employing an experimental laboratory approach. METHODS: Experiments were conducted in the laboratory, where three trophic state conditions were simulated, namely, mesotrophic, eutrophic and hypereutrophic. Each treatment was replicated three times and individuals of Brachionus urceolaris (10 individuals, Hexarthra mira (5 (Rotifera, Latonopsis sp. (10, Moina minuta (10 (Cladocera and Thermocyclops sp. (5 (Copepoda were introduced to each replicate. On the first experiment day, and at 7-day intervals for a 14-day period (totaling three evaluations, all water content was collected from each container and filtered to determine the densities of each zooplankton species. Two-way MANOVA and one-way ANOVA designs were used to determine zooplankton density fluctuations among treatments and throughout the study period. Further, Generalized Linear Models (GLMs were employed to assess how environmental factors affected zooplankton numbers. Phytoplankton composition was also determined in the beginning and in the end of the experiment. RESULTS: B. urceolaris and copepod nauplii, which are typical of eutrophic environments, showed higher densities on the eutrophic and hypereutrophic treatments. Furthermore, cyanobacteria such as Aphanothece sp. and Merismopedia sp. were recorded on the eutrophic and hypereutrophic treatments, respectively. CONCLUSIONS: Similarly to what is frequently observed in the wild, the eutrophic treatment showed higher densities of particular zooplankton species which are known to temporarily benefit from an increase in trophic concentrations. Positive or negative responses from zooplankton dynamics (but also phytoplankton species, provide an important bioindicator framework. Furthermore, results of the present study outline the need for implementing recovery measures on aquatic environments subject to constant nutrient

  15. Dipole vortices in the Great Australian Bight

    DEFF Research Database (Denmark)

    Cresswell, George R.; Lund-Hansen, Lars C.; Nielsen, Morten Holtegaard

    2015-01-01

    Shipboard measurements from late 2006 made by the Danish Galathea 3 Expedition and satellite sea surface temperature images revealed a chain of cool and warm mushroom' dipole vortices that mixed warm, salty, oxygen-poor waters on and near the continental shelf of the Great Australian Bight (GAB...

  16. High Mortality of Red Sea Zooplankton under Ambient Solar Radiation

    OpenAIRE

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

  17. 云龙湖浮游动物对环境变化的响应%Response of Zooplankton in Yunlong Lake to Environmental Change

    Institute of Scientific and Technical Information of China (English)

    李勇; 胡红娟; 李朝; 潘立勇

    2015-01-01

    为了了解徐州市城市湖泊云龙湖浮游动物对水体环境变化的响应,于2012~2013年上、下半年对云龙湖浮游动物群落变化以及相应水体11种理化因子进行了监测分析,并通过冗余分析(RDA)探讨了浮游动物变化与环境因子之间的关系。监测结果表明,4次采样4个点位中共检测到39种微型浮游动物类群,点位间物种群落无明显差异,但年际间物种呈现下降趋势。 RDA分析显示云龙湖浮游动物群落变化主要受石油类,DO,SD,BOD5,TN和Chl-a影响,且石油类,DO,BOD5,及Chl-a可能是造成云龙湖浮游动物群落时间差异的主要原因。%In order to study the effect of water environmental factors on the zooplankton community structure in urban lake, the zooplankton community and water eleven Kinds physicochemical properties in Xuzhou Yunlong Lake were monitored biannually from 2012 to 2013. And, redundancy analysis (RDA)was used to discuss the relationship between zooplankton variation and environmental factors. 39 species of zooplankton were identified, and there was no obvious difference in the zooplankton community composition of each sampling site. But, the results of monitoring showed that the number of species in Yunlong Lake tended to reduce gradually from 2012 to 2013. RDA revealed that the variation of zooplankton community structure in Yunlong Lake were mainly influenced by environmental factors including Petroleum, DO, SD, BOD5, TN, and Chl-a. While, petroleum, DO, BOD5 and Chl-a might be the primary factors that caused temporal disparities of zooplankton community in Yunlong Lake.

  18. Statistical Mechanics of Zooplankton.

    Science.gov (United States)

    Hinow, Peter; Nihongi, Ai; Strickler, J Rudi

    2015-01-01

    Statistical mechanics provides the link between microscopic properties of many-particle systems and macroscopic properties such as pressure and temperature. Observations of similar "microscopic" quantities exist for the motion of zooplankton, as well as many species of other social animals. Herein, we propose to take average squared velocities as the definition of the "ecological temperature" of a population under different conditions on nutrients, light, oxygen and others. We test the usefulness of this definition on observations of the crustacean zooplankton Daphnia pulicaria. In one set of experiments, D. pulicaria is infested with the pathogen Vibrio cholerae, the causative agent of cholera. We find that infested D. pulicaria under light exposure have a significantly greater ecological temperature, which puts them at a greater risk of detection by visual predators. In a second set of experiments, we observe D. pulicaria in cold and warm water, and in darkness and under light exposure. Overall, our ecological temperature is a good discriminator of the crustacean's swimming behavior.

  19. Statistical Mechanics of Zooplankton.

    Directory of Open Access Journals (Sweden)

    Peter Hinow

    Full Text Available Statistical mechanics provides the link between microscopic properties of many-particle systems and macroscopic properties such as pressure and temperature. Observations of similar "microscopic" quantities exist for the motion of zooplankton, as well as many species of other social animals. Herein, we propose to take average squared velocities as the definition of the "ecological temperature" of a population under different conditions on nutrients, light, oxygen and others. We test the usefulness of this definition on observations of the crustacean zooplankton Daphnia pulicaria. In one set of experiments, D. pulicaria is infested with the pathogen Vibrio cholerae, the causative agent of cholera. We find that infested D. pulicaria under light exposure have a significantly greater ecological temperature, which puts them at a greater risk of detection by visual predators. In a second set of experiments, we observe D. pulicaria in cold and warm water, and in darkness and under light exposure. Overall, our ecological temperature is a good discriminator of the crustacean's swimming behavior.

  20. Modelling cyclonic eddies in the Delagoa Bight region

    Science.gov (United States)

    Cossa, O.; Pous, S.; Penven, P.; Capet, X.; Reason, C. J. C.

    2016-05-01

    The objective of this study is to document and shed light on the circulation around the Delagoa Bight region in the southern Mozambique Channel using a realistic modelling approach. A simulation including mesoscale forcings at the boundaries of our regional configuration succeeds in reproducing the general circulation in the region as well as the existence of a semi-permanent cyclonic eddy, whose existence is attested by in situ measurements in the Bight. Characterised by a persistent local minimum in SSH located around 26°S-34°E, this cyclonic eddy termed herein the Delagoa Bight lee eddy occurs about 25% of the time with no clear seasonal preference. Poleward moving cyclones, mostly generated further north, occur another 25% of the time in the Bight area. A tracking method applied to eddies generated in Delagoa Bight using model outputs as well as AVISO data confirms the model realism and provides additional statistics. The diameter of the eddy core varies between 61 and 147 km and the average life time exceeds 20 days. Additional model analyses reveal the systematic presence of negative vorticity in the Bight that can organise and form a Delagoa Bight lee eddy depending on the intensity of an intermittent southward flow along the shore and the spatial distribution of surrounding mesoscale features. In addition, the model solution shows other cyclonic eddies generated near Inhambane and eventually travelling through the Bight. Their generation and pathways appears to be linked with large Mozambique Channel rings.

  1. Zooplankton: its biochemistry and significance in aquaculture

    OpenAIRE

    Kibria, G; Nugegoda, D.; Fairclough, R.; Lam, P.; Bradly, A.

    1997-01-01

    Zooplankton are an important food source for many species of fish. They can provide an inexpensive alternative to other commercial feeds. Zooplankton have several advantages, among them a faster growth and greater feed efficiency for some species. The flavor and texture of fish are also improved with zooplankton as feed. Further research is needed on the chemical composition of zooplankton, the development of zooplankton-based dry diets and the effects of the replacement of fish meal with zoo...

  2. 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...

  3. Start feeding of salmonids with lake zooplankton

    OpenAIRE

    Holm, Jens Christian; Hansen, Tom; Møller, Dag

    1982-01-01

    Fry and small fingerlings of Atlantic salmon (Salmo salar) and rainbow trout (Salmo gairdneri) were fed with lake zooplankton in small fine-meshed cages. The zooplankton were pumped into cages. Growth rates and food selection are discussed.

  4. Zooplankton - Study methods, importance and significant observations

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.

    on zooplankton. By virtue of sheer abundance and intermediatary role between phytoplankton and fish, they are considered as the chief index of utilization of aquatic biotope at the secondary trophic level. The herbivorous zooplanktons is efficient grazers...

  5. Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part1: Wave climate variability and impacts on the longshore sediment transport

    Science.gov (United States)

    Almar, R.; Kestenare, E.; Reyns, J.; Jouanno, J.; Anthony, E. J.; Laibi, R.; Hemer, M.; Du Penhoat, Y.; Ranasinghe, R.

    2015-11-01

    The short, medium and long-term evolution of the sandy coastline of the Bight of Benin in the Gulf of Guinea, West Africa, has become a major regional focal point due to the rapid socio-economic development that is occurring in the region, including rapid urbanization and a sharp increase in harbor-based trade. Harbors have a significant impact on the present evolution of this coast, notably by affecting longshore sediment transport. However, little is known of the environmental drivers, notably the wave climate, that governs longshore sediment transport and the ensuing pattern of shoreline evolution of this coastal zone. This article aims to address this important knowledge gap by providing a general overview of coastal evolution in the Bight of Benin and the physical processes that control this evolution. Here, the 1979-2012 ERA-Interim hindcast is used to understand the temporal dynamics of longshore sediment transport. Oblique waves (annual average Hs=1.36 m, Tp=9.6 s, S-SW incidence) drive an eastward drift of approximately 500,000 m3/yr. The waves driving this large longshore transport can be separated into two components with distinct origins and behavior: wind waves generated locally in the Gulf of Guinea and swell waves generated in the southern hemisphere sub- (30-35°S), and extra-tropics (45-60°S). The analysis undertaken here shows that the contribution to the gross annual longshore transport from swell wave-driven longshore currents is an order of magnitude larger than the local wind wave-driven longshore currents. Swell waves are dominantly generated by westerlies in the 40-60°S zone and to a lesser extent by trade winds at 30-35°S. The longshore sediment drift decay (-5% over 1979-2012) is found to be linked with a decrease in the intensity of westerly winds associated with their southward shift, in addition to a strengthening of the trade winds, which reduces the eastward sediment transport potential. The equatorial fluctuation of the Inter

  6. 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...

  7. Turbulence and zooplankton production: insights from PROVESS

    DEFF Research Database (Denmark)

    Visser, Andre; Stips, A.

    2002-01-01

    Zooplankton are directly influenced by turbulence in both a passive and an active manner. Passively, zooplankton are at the mercy of turbulence in how it affects their vertical mixing, encounter rate, detection abilities and feeding current efficiency. Many zooplankton species, however, are...

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

    Directory of Open Access Journals (Sweden)

    Ali M Al-Aidaroos

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

  9. Zooplankton in the Arctic outflow

    Science.gov (United States)

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

    2009-04-01

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

  10. Studies on zooplankton of Lago Paione Superiore

    Directory of Open Access Journals (Sweden)

    Patrizia COMOLI

    1999-08-01

    Full Text Available We report here the results of a three year study on the zooplankton of Lago Paione Superiore, an acid sensitive lake above the tree line in the Italian Alps. The research was carried out within MOLAR, an EC-founded Project on “Measuring and Modeling the dynamic response of remote mountain lakes ecosystems to environmental change”. This study comes after a series of investigations on the effects of acidification, in which we documented the changes occurred with decreasing water pHs, by comparing the recent situation with that in the literature of the 40s, and reconstructed the beginning of anthropogenic disturbance through an analysis of the past cladocera assemblages archived in the lake sediments. A characteristic pattern in seasonal periodicity is a transition from a community dominated by small zooplankton (August to a community where the large particle-feeder Daphnia longispina dominates. This is a typical pattern observed in fishless, copepod-cladocera lakes. Regardless from which food is able to exploit, Daphnia population of Lago Paione Superiore is composed by well-fed organisms, visually rich in lipids, able to produce more than one generation/ year of parthenogenetic females at density levels which are rather high in an oligotrophic high mountain lake.

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

    Data.gov (United States)

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

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

    OpenAIRE

    Sónia Cotrim Marques; Anda Ikauniece; Catriona Clemmesen; Frederiz Azemar; Ilppo Vuorinen; Myron Peck; Patrick Meire; Ulf Bamstedt; Sami Souissi

    2014-01-01

    Several recent studies have revealed the impacts of the climate variability in the dynamic of zooplankton in different estuarine ecosystems, imposing a need for more and continued global studies. Presently, there is a growing appreciation in international collaborations to compare and contrast estuarine ecosystem response to climate variability across geographical gradients, including long-term changes in zooplankton. We performed a meta-analysis comprising field data from 7 location (Mondego...

  13. Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

    Science.gov (United States)

    Makinen, Carla; Moisan, Tiffany A. (Editor)

    2012-01-01

    As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

  14. Zooplankton research off Peru: A review

    Science.gov (United States)

    Ayón, Patricia; Criales-Hernandez, Maria I.; Schwamborn, Ralf; Hirche, Hans-Jürgen

    2008-10-01

    A review of zooplankton studies conducted in Peruvian marine waters is given. After a short history of the development of zooplankton research off Peru, we review zooplankton methodology, taxonomy, biodiversity, spatial distribution, seasonal and interannual variability, trophodynamics, secondary production, and modelling. We review studies on several micro-, meso-, macro-, and meroplankton groups, and give a species list from both published and unpublished reports. Three regional zooplankton groups have been identified: (1) a continental shelf group dominated by Acartia tonsa and Centropages brachiatus; (2) a continental slope group characterized by siphonophores, bivalves, foraminifera and radiolaria; (3) and a species-rich oceanic group. The highest zooplankton abundances and biomasses were often found between 4-6°S and 14-16°S, where continental shelves are narrow. Species composition changes with distance from the shore. Species composition and biomass also vary strongly on short time scales due to advection, peaks of larval production, trophic interactions, and community succession. The relation of zooplankton to climatic variability (ENSO and multi-decadal) and fish stocks is discussed in the context of ecological regime shifts. An intermediate upwelling hypothesis is proposed, based on the negative effects of low upwelling intensity in summer or extremely strong and enduring winter upwelling on zooplankton abundance off Peru. According to this hypothesis, intermediate upwelling creates an optimal environmental window for zooplankton communities. Finally, we highlight important knowledge gaps that warrant attention in future.

  15. Microscale nutrient patches produced by zooplankton

    OpenAIRE

    John T. LEHMAN; Scavia, Donald

    1982-01-01

    Both track autoradiography and grain-density autoradiography show that individual zooplankton create miniature patches of dissolved nutrients and that algae exploit those regions to absorb phosphate. The patches are short lived and can be dispersed artificially by small-scale turbulence. Our data support a simple model of encounters between algae and nutrient plumes produced by swimming zooplankton.

  16. 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.

  17. Zooplankton of the Zaporiz’ke Reservoir

    OpenAIRE

    T. V. Mykolaichuk

    2006-01-01

    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. Lake Ontario zooplankton in 2003 and 2008: community changes and vertical redistribution

    Science.gov (United States)

    Rudstam, Lars G.; Holeck, Kristen T.; Bowen, Kelly L.; Watkins, James M.; Weidel, Brian C.; Luckey, Frederick J.

    2014-01-01

    Lake-wide zooplankton surveys are critical for documenting and understanding food web responses to ecosystem change. Surveys in 2003 and 2008 during the binational intensive field year in Lake Ontario found that offshore epilimnetic crustacean zooplankton declined by a factor of 12 (density) and factor of 5 (biomass) in the summer with smaller declines in the fall. These declines coincided with an increase in abundance of Bythotrephes and are likely the result of direct predation by, or behavioral responses to this invasive invertebrate predator. Whole water column zooplankton density also declined from 2003 to 2008 in the summer and fall (factor of 4), but biomass only declined in the fall (factor of 2). The decline in biomass was less than the decline in density because the average size of individual zooplankton increased. This was due to changes in the zooplankton community composition from a cyclopoid/bosminid dominated community in 2003 to a calanoid dominated community in 2008. The increase in calanoid copepods was primarily due to the larger species Limnocalanus macrurus and Leptodiaptomus sicilis. These coldwater species were found in and below the thermocline associated with a deep chlorophyll layer. In 2008, most of the zooplankton biomass resided in or below the thermocline during the day. Increased importance of copepods in deeper, colder water may favor cisco and rainbow smelt over alewife because these species are better adapted to cold temperatures than Alewife.

  19. 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 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.

  20. Zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Madhu, N.V.

    ://www.ngdc.noaa.gov/mgg/topo/globe.html. Godhantaraman N. (1994) Species composition and abundance of tintinnids and copepods in the Pichavaram mangroves (South India); Ciencias Marinas 20 371?391. Goswami S. C. (1983) Coexistence and succession of copepod species in the Mandovi and Zuari estuaries...

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

    Science.gov (United States)

    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

  2. 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

  3. 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...

  4. Bacterial diversity associated with freshwater zooplankton

    DEFF Research Database (Denmark)

    Grossart, Hans-Peter; Dziallas, Claudia; Tang, Kam W.

    2009-01-01

    Bacterial community compositions (BCC) associated with the cladoceran Bosmina coregoni and the cyclopoid copepod Thermocyclops oithonoides in oligotrophic Lake Stechlin versus eutrophic Lake Dagow (northeastern Germany) were compared using molecular techniques. We also transplanted the zooplankton...

  5. Trait-based approaches to zooplankton communities

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... and ecosystem models is necessary to generate realistic predictions on the functioning of aquatic ecosystems but remains extremely challenging. We propose that the use of trait-based approaches is a promising way to reduce complexity while retaining realism in developing novel descriptions of zooplankton...... traits, such as body size and motility, transcend several functions and are major determinants of zooplankton ecological strategies. Future developments of trait-based approaches to zooplankton should assemble a comprehensive matrix of key traits for diverse groups and explore it for general patterns...

  6. Carbon export by vertically migrating zooplankton

    DEFF Research Database (Denmark)

    Hansen, Agnethe Nøhr; Visser, André W.

    2016-01-01

    of the active transport of carbon by different size fractions of the migrating zooplankton population as function of time and space. The approach is motivated by the difficulty in incorporating behavioral aspects of carbon transport into large scale carbon budgets of the world's oceans. The results show......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 characteristic...... that despite their lower abundance, large zooplankton (length circa 1–2 mm) migrate deeper and transport approximately twice as much carbon as do the smaller zooplankton (length circa 0.2–0.3 mm). In mid- latitudes (∼30°N to ∼45°N), where pronounced spring blooms are observed, up to 20% more carbon...

  7. Continental shelf processes affecting the oceanography of the South Atlantic Bight. Progress report, June 1, 1978--May 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, L P

    1979-03-01

    Progress is reported on the following research projects: nitrogen inputs to the South Atlantic Bight; eddy experiments for obtaining quasi-synoptic map of South Atlantic Bight; cruise experiment for observation of stranded intrusion in the South Atlantic Bight; geographic distribution of hydrographic data; and computer plotting and contouring of data. (HLW)

  8. A seafloor crater in the German Bight and its effects on the benthos

    Science.gov (United States)

    Thatje, S.; Gerdes, D.; Rachor, E.

    1999-08-01

    In 1963 a deep crater was formed about 65 m below sea level in the western part of the German Bight, due to a gas eruption caused by drilling carried out from the platform 'Mr. Louie'. The study area is situated in a sandy to muddy bottom area inhabited by an Amphiura filiformis association (sensu Salzwedel et al. 1985). The crater, sometimes called 'Figge-Maar', functions as a sediment trap, concentrating particles and organisms from the water column, thus leading to extreme sedimentation rates of about 50 cm, on average, per year. Crater stations, compared with stations situated in the vicinity, show enrichments of juveniles. Echinoderms, especially the subsurface-dwelling heart urchin Echinocardium cordatum and ophiuroids are responsive to enrichment. Other species that are typical of the Amphiura filiformis association are shown to be unable to cope with the special conditions in the crater.

  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. 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.

  11. Zooplankton communities in the Krenceng Reservoair, Cilegon, Banten

    Directory of Open Access Journals (Sweden)

    Mufti P. Patria

    2005-11-01

    Full Text Available This research was carried out to know the structure of zooplankton communities and relations between the phytoplankton and zooplankton in the Krenceng Reservoair, Cilegon. The zooplankton abundance with used Sedwigck Rafter Counting Method, diversity and evenness were counted. Relations between zooplankton and the environmental factors as well as its relations to phytoplankton calculated with regression. The results showed that are 13 species of the zooplankton found which including in three classes with the highest abundance on Novembers 2002 and March 2003 of the Rotifera. The analysis of regression pointed out that the environmental factors such: pH, BOD5, nitrate, CO2 and abundance of phytoplankton influence the abundance zooplankton in November. While in March, the abundance of zooplankton is influenced by brigthtness, nitrate, orthophosphates and C organic. The abundance of phytoplankton influenced positively by the abundance of zooplankton.

  12. Southern California Bight 2003 Regional Monitoring Program: V. water quality

    Science.gov (United States)

    Nezlin, Nikolay P.; DiGiacomo, Paul M.; Weisberg, Stephen B.; Diehl, Dario W.; Warrick, Jonathan A.; Mengel, Michael J.; Jones, Burton H.; Reifel, Kristen M.; Johnson, Scott C.; Ohlmann, J. Carter; Washburn, Libe; Terrill, Eric J.

    2007-01-01

    More than $30 million is expended annually on environmental monitoring in the Southern California Bight (SCB), yet only 5% of the Bight is monitored on an ongoing basis. Therefore, environmental managers in the SCB decided to expand their monitoring program and, starting in 1994, decided to conduct periodic regional assessments of ecosystem condition and assess the overall health of the SCB. Sixty-five different organizations collaborated in 2003 to create the third SCB Regional Monitoring Program (Bight '03). Bight '03 was designed to be integrated regional monitoring program that encompasses regulatory, academic, and non-governmental agencies. Bight '03 had three components: Coastal Ecology, Shoreline Microbiology, and Water Quality. This report addresses the purpose, approach, findings, and recommendations from the Water Quality component, which focused on contamination-laden stormwater runoff, in particularly its variability in time and space as well as its short-term ecological impacts. Specifically, the Bight '03 Water Quality component had three primary goals, the first of which was to described the temporal evolution of stormwater plumes produced by the major southern California rivers. Specifically, the study was intended to determine how far offshore the plumes extended, how rapidly they advected, how long before the plumes dispersed and how these properties differed among storms and river systems. The second goal was to describe how the physical properties (e.g., turbidity, temperature, salinity) of the plume related to biogeochemical and ecological properties that are of more direct concern to the water quality management community. Accomplished primarily through ship-based sampling of water quality parameters, this second goal was to describe how far offshore, and for how ;long after the storm, elevated bacterial concentrations, toxicity, and nutrients could be detected. Similar to the fist goal, the study also addressed how these answers differed

  13. Bacteria dispersal by hitchhiking on zooplankton

    DEFF Research Database (Denmark)

    Grossart, Hans-Peter; Dziallas, Claudia; Leunert, Franziska;

    2010-01-01

    and nonpathogenic bacteria has shown that direct association with zooplankton has significant influences on the bacteria's physiology and ecology. We used stratified migration columns to study vertical dispersal of hitchhiking bacteria through migrating zooplankton across a density gradient that was otherwise...... impenetrable for bacteria in both upward and downward directions (conveyor-belt hypothesis). The strength of our experiments is to permit quantitative estimation of transport and release of associated bacteria: vertical migration of Daphnia magna yielded an average dispersal rate of 1.3 x 10(5) x cells x...... Daphnia(-1) x migration cycle(-1) for the lake bacterium Brevundimonas sp. Bidirectional vertical dispersal by migrating D. magna was also shown for two other bacterial species, albeit at lower rates. The prediction that diurnally migrating zooplankton acquire different attached bacterial communities from...

  14. Experimental whole-lake increase of dissolved organic carbon concentration produces unexpected increase in crustacean zooplankton density.

    Science.gov (United States)

    Kelly, Patrick T; Craig, Nicola; Solomon, Christopher T; Weidel, Brian C; Zwart, Jacob A; Jones, Stuart E

    2016-08-01

    The observed pattern of lake browning, or increased terrestrial dissolved organic carbon (DOC) concentration, across the northern hemisphere has amplified the importance of understanding how consumer productivity varies with DOC concentration. Results from comparative studies suggest these increased DOC concentrations may reduce crustacean zooplankton productivity due to reductions in resource quality and volume of suitable habitat. Although these spatial comparisons provide an expectation for the response of zooplankton productivity as DOC concentration increases, we still have an incomplete understanding of how zooplankton respond to temporal increases in DOC concentration within a single system. As such, we used a whole-lake manipulation, in which DOC concentration was increased from 8 to 11 mg L(-1) in one basin of a manipulated lake, to test the hypothesis that crustacean zooplankton production should subsequently decrease. In contrast to the spatially derived expectation of sharp DOC-mediated decline, we observed a small increase in zooplankton densities in response to our experimental increase in DOC concentration of the treatment basin. This was due to significant increases in gross primary production and resource quality (lower seston carbon-to-phosphorus ratio; C:P). These results demonstrate that temporal changes in lake characteristics due to increased DOC may impact zooplankton in ways that differ from those observed in spatial surveys. We also identified significant interannual variability across our study region, which highlights potential difficulty in detecting temporal responses of organism abundances to gradual environmental change (e.g., browning). PMID:26919470

  15. Experimental whole-lake increase of dissolved organic carbon concentration produces unexpected increase in crustacean zooplankton density

    Science.gov (United States)

    Kelly, Patrick T.; Craig, Nicola; Solomon, Christopher T.; Weidel, Brian C.; Zwart, Jacob A.; Jones, Stuart E.

    2016-01-01

    The observed pattern of lake browning, or increased terrestrial dissolved organic carbon (DOC) concentration, across the northern hemisphere has amplified the importance of understanding how consumer productivity varies with DOC concentration. Results from comparative studies suggest these increased DOC concentrations may reduce crustacean zooplankton productivity due to reductions in resource quality and volume of suitable habitat. Although these spatial comparisons provide an expectation for the response of zooplankton productivity as DOC concentration increases, we still have an incomplete understanding of how zooplankton respond to temporal increases in DOC concentration within a single system. As such, we used a whole-lake manipulation, in which DOC concentration was increased from 8 to 11 mg L−1 in one basin of a manipulated lake, to test the hypothesis that crustacean zooplankton production should subsequently decrease. In contrast to the spatially derived expectation of sharp DOC-mediated decline, we observed a small increase in zooplankton densities in response to our experimental increase in DOC concentration of the treatment basin. This was due to significant increases in gross primary production and resource quality (lower seston carbon-to-phosphorus ratio; C:P). These results demonstrate that temporal changes in lake characteristics due to increased DOC may impact zooplankton in ways that differ from those observed in spatial surveys. We also identified significant interannual variability across our study region, which highlights potential difficulty in detecting temporal responses of organism abundances to gradual environmental change (e.g., browning).

  16. 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...

  17. 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

  18. Southern California Bight Sea Level Response to Local Atmospheric Forcing

    OpenAIRE

    Fu, T C-Y; Flick, R E; D. R. Cayan; Talley, L D

    1988-01-01

    In terms of loss of life and property damage, storm induced coastal flooding has become the world's foremost natural hazard. As atmospheric weather systems pass over ocean areas, water level oscillations are induced both by the wind stress and the horizontal gradients in atmospheric pressure associated with such systems. Storm surge is by definition restricted to the storm induced oscillations of water level with periods ranging from a few minutes to a few days. This definition excludes the w...

  19. Zooplankton succession in fingerling production ponds

    Science.gov (United States)

    Many pond cultured species require a range of zooplankton species for consumption before they can be weaned onto manufactured feed. The widest variety of plankton species develops when empty ponds are filled and fertilized. Use of organic and inorganic fertilizers facilitates the development of ba...

  20. Is the zooplankton of the tropics different?

    Institute of Scientific and Technical Information of China (English)

    Henri J.Dumont

    2008-01-01

    @@ The zooplankton,defined a the assemblage of animals and animal-like creatures that lives in the water column of small to big waterbodies,has primarily been studied in the temperate zone,so most "received" concepts about it derive from the temperate,not the tropical belt of this planet.

  1. Fish-mediated trait compensation in zooplankton

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  2. Multibeam Mapping of the South Atlantic Bight: Georgia 2005, a Proposed MPA on the Continental Shelf

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Fisheries laboratory in Panama City, Florida coordinated an acoustic survey at the new proposed Marine Protected Areas in the South Atlantic Bight area...

  3. Habitat classification from multibeam. SEFIS Survey Areas in the South Atlantic Bight, 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a vector shapefile describing the geomorphology of 21 areas along the shelf edge off the South Atlantic Bight where NOAA South East Fisheries...

  4. Marine Ecosystems Analysis (MESA) Program, New York Bight Surficial Sediment Analyses

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Ecosystems Analysis (MESA) Program, New York Bight Study was funded by NOAA and the Bureau of Land Management (BLM). The Atlas was a historical...

  5. Biological processes in the water column of the South Atlantic bight

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhoefer, G.A.; Yoder, J.A.

    1980-01-31

    Progress is reported on research conducted during 1979 on the biological oceanography of the South Atlantic Bight. The presentation consists of a number of published articles and abstracts of oral presentations. (ACR)

  6. Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

    Institute of Scientific and Technical Information of China (English)

    GAO Xuelu; SONG Jinming; LI Xuegang

    2011-01-01

    Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003,including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e.abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.

  7. Temporal variations in lead concentrations and isotopic composition in the Southern California Bight

    Energy Technology Data Exchange (ETDEWEB)

    Sanudo-Wilhelmy, S.A.; Flegal, A.R. (Univ. of California, Santa Cruz, CA (United States))

    1994-08-01

    Lead concentrations in surface waters of the Southern California Bight appear to have decreased threefold (from >170 to <60 pM) since they were initially measured by Clair Patterson and his associates in the 1970s. The decrease parallels a threefold decline in anthropogenic inputs of industrial lead to the bight over the past two decades. Moreover, mass balance calculations indicate that the primary source of lead to the bight now is upwelling. This is evidenced by the isotopic compositions of surface waters in the bight, which are most characteristic of Asian industrial lead aerosols (0.4793 [le] [sup 206]Pb/[sup 208]Pb [le] 0.4833) deposited in oceanic waters of the North Pacific. While the decrease in surface water lead concentrations in the bight reflects the reduction in industrial lead emissions from the United States, the isotopic compositions of surface waters in the southern reach of the bight reflect a concurrent increase in industrial lead emissions from Mexico (0.4852 [le] [sup 206]Pb/[sup 208]Pb [le] 0.4877). The isotopic composition ([sup 208]Pb/[sup 207]Pb [approximately] 2.427) of elevated lead concentrations of surface waters in San Diego Bay indicate that lead is being remobilized from contaminated sediments within that bay.

  8. 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

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

    International Nuclear Information System (INIS)

    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 90Sr in water was 2.8 kBq/l, 137Cs - 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/m3 (given the mean and standard deviation), in 2012 - 26.0±0.9 million individuals/m3. The main contribution was that of rotifers: 88.5 % of the

  10. Zooplankton Distribution in Tropical Reservoirs, South China

    Science.gov (United States)

    Lin, Qiu-Qi; Duan, Shun-Shan; Hu, Ren; Han, Bo-Ping

    2003-11-01

    The zooplankton of 18 reservoirs of South China was investigated in 2000. 61 Rotifera species, 23 Cladoceras and 14 Copepodas were identified. The most frequent Rotifera genera were Keratella, Brachionus, Trichocerca, Diurella, Ascomorpha, Polyarthra, Ploesoma, Asplanchna, Pompholyx and Conochilus. Bosmina longirostris, Bosminopsis deitersi, Diaphanosoma birgei, D. brachyurum and Moina micrura were typical of Cladocera in the reservoirs. Phyllodiaptomus tunguidus, Neodiaptomus schmackeri and Mesocyclops leuckarti were the most frequent Copepoda and M. leuckarti dominated Copepoda in most reservoirs. High zooplankton species richness with low abundance was characteristic of the throughflowing reservoir, whereas low species richness with low abundance was found in the reservoir with the longest retention time. Relative high abundance and medium species diversity were the distinction of intermediate retention time reservoirs.

  11. Zooplankton composition and abundance in Mida Creek, Kenya

    OpenAIRE

    Osore, M.K.W.; Mwaluma, J.M.; FIERS, F; Daro, M.H.

    2004-01-01

    In order to determine the resident assemblages of zooplankton in Mida Creek, Kenya, a survey was conducted from May 1996 to Apr. 1997 for which we studied their seasonal composition, abundance, and distribution. Twenty-seven major zooplankton taxa were identified. The order Copepoda was the most abundant taxon dominated mainly by the genera Acartia, Paracalanus, Labidocera, Temora, Centropages, and Calanopia. Other common zooplankton taxa included the Medusae, Ctenophora, Brachyura larvae, an...

  12. Circulation in the Hudson Shelf Valley: MESA Physical Oceanographic Studies in New York Bight, 1

    Science.gov (United States)

    Mayer, Dennis A.; Han, Gregory C.; Hansen, Donald V.

    1982-11-01

    Over 900 days of current velocity data were obtained at mainly two locations in the inner and outer Hudson Shelf Valley (HSV). The large cross-axis depth gradients in the HSV, together with the strong winter cyclones and the baroclinic density distribution over the shelf, are primarily responsible for the major circulation features observed in the valley. CSTD data from 12 cruises and meteorological data from JFK International Airport and an environmental buoy were collected concurrently with the current meter data. Although the mean cross-shelf pressure gradient is generally seaward in the Middle Atlantic Bight, it is shoreward in the HSV below the level of the adjacent continental shelf (shelf horizon), thus imposing a bias toward upvalley flow. The average velocity below the surrounding shelf horizon in the HSV is upvalley or shoreward (west-northwestward ≈ 290° T) in the range of 2-5 cm/s. The circulation in the HSV is seasonal and individual events can drastically alter the mean picture. The several day average upvalley flow can sometimes approach 20 cm/s when intense winter cyclones pass over the bight and can sometimes also be directed downvalley depending upon the path of the winter cyclone. A topographically controlled barotropic flow commonly opposes the dominant (southeast-ward) wind direction even near the surface in the winter. In the context of circulation on the open shelf, upvalley (downvalley) flow events generated by winter cyclones are associated with reduced (enhanced) southwestward flow or flow reversals that are northeastward in the lower half of the water column at LTM, a typical mid/shelf site (Mayer et al., 1979). Current meter data suggest that whether or not reversals occur on the open shelf depends upon the interannual variability of the winter wind regime. Upvalley flow events are not confined only to the winter (unstratified) season but are stronger in the winter and can last for several days and longer. During the summer

  13. Evaluation of abiotic stresses of temperate estuaries by using resident zooplankton: A community vs. population approach

    Science.gov (United States)

    Paul, Sourav; Wooldridge, Tris; Perissinotto, Renzo

    2016-03-01

    By using permanently resident zooplankton, we assessed the ecological level (i.e. community and or population) that provides more in-depth indication of the stress related to salinity and temperature fluctuations in temperate estuaries. In the semi-arid warm temperate South Africa, the Gamtoos estuary experiences a full salinity gradient maintained by irregular but relatively frequent freshwater pulses, whereas the Kromme estuary is euhaline throughout its extent and receives only occasional freshwater inputs when the storage reservoir six km upstream overtops. Changes in the species evenness index of Pielou and the abundances of estuarine resident zooplankton species were modelled against salinity and temperature variations of respective estuaries. In the Gamtoos estuary, response of individual populations provided more in-depth information regarding zooplankton variability. However the most abundant resident zooplankton i.e. Acartia longipatella a copepod was not the best predictor of the salinity and temperature fluctuations. Conversely, the Kromme estuary study provided insights into the potential vulnerability of the resident estuarine zooplankton community to cold. Further, the population level study exposed responses of specific species against salinity changes. We discuss the pros and cons of designing ecological indicators of abiotic stress based on specific species, targeted to specific ecological level, and needs of considering the frequency and magnitude of fresh water inflow in an estuary. A suggestion is to use specific taxonomic group(s) (e.g. Copepods) to better understand the abiotic stress factors of specific set of estuaries (e.g. freshwater rich/starved) until a 'one size fits all' indicator is found for temperate estuaries.

  14. A Lagrangian Physical-Biological Model to Study Water Parcels Associated with Algal Blooms from Southern California Bight to Todos Santos Bay.

    Science.gov (United States)

    Vivas Téllez, I. E.; Rivas, D.

    2015-12-01

    Lagrangian ocean circulation and biological dynamics are numerically studied in Todos Santos Bay during the spring of 2007. This period is particularly interesting after an intense toxic algal bloom occurred in April 2007 in this area, which was associated with the wind-driven upwelling in the region. High resolution, numerical model simulations were carried out to study dynamical features along of the Southern California Bight (SCB), the coast of the northern Baja California (BC), and the interior of Todos Santos Bay (TSB). These simulations are used in a three-dimensional Lagrangian (particle tracking) analysis which provides information about the origin and distribution of the waters present in the Bay during the occurrence of the toxic bloom. After the selection of trajectories of particles showing coherent patterns, a Nitrate-Phytoplankton-Zooplankton-Detritus (NPZD) lower trophic model is implemented to study the influence of the environmental conditions that occur during the particle advection, solving the NPZD equations at every time-varying position of the advected particles. The model is also modified for phytoplankton growth as a function of the environmental temperature to somehow emulate the life cycle of Pseudo-nitzschia. The analysis of the trajectories shows that particles mainly come from two regions: from the north, in the southern portion of SCB and from regions west of the TSB. Knowing the regional circulation patterns and their phytoplankton dynamics can help to understand and even predict the origin and destination of the harmful algal blooms that occur in TSB and its surroundings.

  15. Seasonal and interannual variability of physical and biological dynamics at the shelfbreak front of the Middle Atlantic Bight: nutrient supply mechanisms

    Directory of Open Access Journals (Sweden)

    R. He

    2011-10-01

    Full Text Available A high-resolution, 3-dimensional coupled biophysical model is used to simulate ocean circulation and ecosystem variations at the shelfbreak front of the Middle Atlantic Bight (MAB. Favorable comparisons between satellite observations and model hindcast solutions from January 2004 to November 2007 indicate the model has intrinsic skills in resolving fundamental physical and biological dynamics at the MAB shelfbreak. Seasonal and interannual variability of ocean physical and biological states and their driving mechanisms are further analyzed. The domain-wide upper water column nutrient content is found to peak in late winter-early spring. Phytoplankton spring bloom starts 1–2 months later, followed by zooplankton bloom in early summer. Our analysis shows the variability of shelfbreak nutrient supply is controlled by local mixing that deepens the mixed layer and injects deep ocean nutrients into the upper water column and alongshore nutrient transport by the shelfbreak jet and associated currents. Nutrient vertical advection associated with the shelfbreak bottom boundary layer convergence is another significant contributor. Spring mean nutrient budget diagnostics along the Nantucket transect are compared between nutrient rich 2004 and nutrient poor 2007. Physical advection and diffusion play the major role in determining strong interannual variations in shelfbreak nutrient content. The biological (source minus sink term is very similar between these two years.

  16. Distribution of Zooplankton in the Jiaojiang Estuary and Its Response to Environment Factors in Spring and Autumn%椒江口春、秋季浮游动物分布特征及与主要环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    杜萍; 徐晓群; 刘晶晶; 曾江宁; 陈全震; 寿鹿; 廖一波; 周青松

    2011-01-01

    2009年明和10月对椒江口( 121.35°E~121.85°E,28.50°N~28.80°N)浮游动物进行调查,分析其群落结构、生物量和丰度的时空分布特征及与主要环境因子的关系.结果表明,该海域浮游动物有明显的季节变化,春季鉴定到14大类50种,卡玛拉水母(Malagazzia carolinae)为绝对优势种,秋季鉴定到14大类73种,优势种分别为百陶箭虫(Sagitta bedoti)、双生水母(Diphyes chamissonis)、亚强真哲水蚤(Eucalanus subcrassus)、微刺哲水蚤(Canthocalanus pauper)、中华胸刺水蚤(Centropages sinensis)和肥胖箭虫(Sagitta enflata);多样性指数为秋季(2.59)高于春季(1.82),生物量和丰度为春季(972.66mg/m3和1 743.54 ind/m3)远高于秋季(65.30 mg/m3和31.94 ind/m3).总生物量和丰度的空间分布由优势种决定,春季高值区出现在咸淡水交汇的出海口处;秋季有沿河口向外递增的趋势.典范对应分析(CCA)表明,营养盐、盐度和溶解氧为影响春秋季椒江口浮游动物分布的环境因子;浮游动物群落存在明显的季节和空间异质性;各物种适宜的生态环境不同.与类似河口的现状相比,椒江口的浮游动物种类丰富,可能与影响该河口的水团多样有关;与历史资料相比,椒江口4、10月份浮游动物的生物量、丰度及优势类群保持相对稳定.%To investigate the temporal and spatial distribution of community structure, biomass and abundance of zooplankton in the Jiaojiang Estuary and its response to environmental factors in different season, two cruises in the Jiaojiang Estuary were carried out in May and October 2009, respectively. Totally, 106 species were identified in all samples, belonging to 16 groups. Among them copepod was the dominant group, followed by pelagic larva and hydromedusae. Our results indicated that species composition presented significant seasonal variation. Totally, 50 species in 14 groups were identified in spring, and Malagazzia carolinae was

  17. Seasonal patterns of surface wind stress and heat flux over the Southern California Bight

    Science.gov (United States)

    Winant, Clinton D.; Dorman, Clive E.

    1997-03-01

    Patterns of wind stress and heat flux between the atmosphere and the ocean over the Southern California Bight are described based on observations from buoys and ships. During the winter, the wind stress is spatially homogeneous and temporally variable, with strong events corresponding to low-pressure systems sweeping through the area. During the summer, spatial patterns are more persistent, with large gradients. Inshore of a line running approximately between Point Conception and Ensenada, Mexico, winds are weak. Offshore wind speeds are comparable in magnitude to those found over the continental shelf north of Point Conception. The boundary is the location of maximum wind stress curl, and the spatial resolution afforded by California Cooperative Fisheries Investigation (CalCOFI) observations suggests maximum wind stress curls over 3 times larger than the values proposed by Nelson [1977]. Net heat flux estimates derived from the CalCOFI measurements are somewhat larger than the values proposed by Nelson and Husby [1983], due to differences in latent heat flux estimates. Possible mechanisms responsible for the spring-summer spatial structure in the wind and the relationship between these gradients and the properties of the underlying ocean are discussed.

  18. The role of density gradients on tidal asymmetries in the German Bight

    Science.gov (United States)

    Stanev, Emil V.; Al-Nadhairi, Rahma; Valle-Levinson, Arnoldo

    2015-01-01

    The dynamics of the German Bight associated with river plumes and fresh water intrusions from tidal flats have been studied with numerical simulations. The horizontal and vertical patterns of the M2, M4 and M6 tides revealed complex distortions along the bathymetric channels connecting the coast and the open sea. A major focus was on the surface-to-bottom change in tidal asymmetries, which provides a major control on draining the tidal flats around the Elbe and Weser River mouths. Comparisons between baroclinic and barotropic experiments demonstrated that the estuarine gravitational circulation is responsible for pronounced differences in surface and bottom asymmetries. These differences could be considered as a basic control mechanism for sediment dynamics. The most prominent area of tidal distortions, manifested by a delay of the tidal wave, was located between the estuarine turbidity maximum and the estuarine mouth north of Cuxhaven. This area was characterized by the strongest periodic convergence and divergence of the flow and by the largest salinity gradients. The enhancement of the gravitational circulation occurred during the transition between spring and neap tides. The large-scale dynamics and small-scale topographic features could impact the sediment distribution as there was a marked interplay in the channels between stratification and turbulence. Also an explanation has been given for the mechanisms supporting the existence of a mud area ( Schlickgebiet) south of Helgoland Island, associated with trapping suspended particular matter.

  19. Fine-scale spatial and temporal plankton distributions in the Southern California Bight: lessons from in situ microscopes and broadband echosounders

    Science.gov (United States)

    Briseno-Avena, Christian

    Phytoplankton and zooplankton are important components of marine ecosystems, and play a major role in the biological pump, affecting carbon transport in the global oceans. Their dynamic heterogeneous spatial and temporal distributions require special tools for observing them at the ecological scales relevant to the individual organisms. In this work, I used optic and acoustic methods to study plankton organisms at spatial scales of meters and temporal scales ranging from minutes to months. Using two in situ microscopes I described the fine-scale vertical distribution of phytoplankton and several zooplankton taxa in a coastal location in the Southern California Bight. Highly resolved spatial observations revealed cryptic maxima of fluorescent particles not observed with traditional fluorometers. Furthermore, this high sampling resolution revealed that water density, and not depth, regulated the vertical position, and interactions between observed phytoplankton and zooplankton distributions. Underwater acoustic echosounders can be powerful tools to observe in situ plankton distributions. Interpreting the acoustic echoes, however, requires highly calibrated instruments and ground-truthing experiments to identify the source of acoustic signals. This work presents the description of a novel combination of a broadband, high-frequency (1.5-2.5 MHz) echosounder and a stereoscopic camera --combined, these systems can localize the echo produced by an individual target while simultaneously providing visual identification of the target. This work has provided one of the first comparisons of in situ measured broadband target strength (BTS) and the expected signal using a physical model. The results of this experiment revealed unexpected, important differences between measured and modeled BTS. This system was also used to make in situ observations of individual fragile gelatinous organisms, marine snow particles and phytoplankton, providing evidence of their significant acoustic

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

    Science.gov (United States)

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

    2011-03-01

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

  1. Systematics and distribution of zooplankton in Lake Victoria basin, Kenya

    OpenAIRE

    Masai, D.M.; Omondi, R.; Owili, M.

    2006-01-01

    Zooplankton samples were collected, using a 60~km nansen net, from Lake Victoria (Kenya) and adjacent water bodies with emphasis being placed on the different habitats within the ecosystems. A total of 116 species were identified, 63 rotifers, 24 cladocerans and 29 copepods. A number of these were new records for the zooplankton fauna for the country.

  2. 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...

  3. 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 P-excre

  4. Census of Marine Zooplankton CmarZ Information

    NARCIS (Netherlands)

    A.C. Pierrot-Bults; A. Bucklin

    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, ge

  5. Harvesting and Processing Zooplankton for Use as Supplemental Fry Feed

    Science.gov (United States)

    We present the methods that we used to capture and dry large zooplankton from ponds to feed to channel catfish Ictalurus punctatus fry. Using a submersible pump and canister filter, we were able to capture about 1.0 kg (wet weight; 200 g in terms of dry weight) of zooplankton from well-fertilized po...

  6. Zooplanktonic diversity in the western Pacific

    OpenAIRE

    Mao Lin; Chunguang Wang; Yanguo Wang; Peng Xiang; Yu Wang; Guangshan Lian; Ruixiang Chen; Xiaoyin Chen; Youyin Ye; Yanyu Dai; Jinghong Lin; Zhenzu Xu; Jiaqi Huang; Donghui Guo

    2011-01-01

    The western Pacific region has been operating as a centre for the origin of marine biodiversity: the richest diversity of many marine taxa was found in these waters. Therefore, biodiversity research and con-servation efforts in this area are necessary in order to promote the integrative and international management of this resource. The present work is a compilation of numbers of all the families, genera and species of ma-jor taxa of zooplankton known in the western Pacific Ocean(106°–150°E, ...

  7. Zooplankton Methodology, Collection & identyification - A field manual

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    , zooplankton, benthos and other flora and fauna under the Project ? Measurement and Mapping of Marine Resources?. Although the mandate of the project has been diversified with changing times, the taxonomic identification continues to remain the thrust area... of water passed through the net. For this purpose, an instrument called flow meter is used. It should not be mistaken for current meter. The flow meter (Fig. 2) has a multi bladed propeller, which is rotated by the flow of water. There is a counter, which...

  8. Seasonal hypoxia regulates macrobenthic function and structure in the Mississippi Bight.

    Science.gov (United States)

    Rakocinski, Chet F; Menke, Daneen P

    2016-04-15

    Hypoxic conditions are escalating to the east of the Mississippi River within the Mississippi Bight. The objective of this study was to examine changes in macrobenthic function and structure relative to seasonal hypoxia over a 3.5year period at the 10m (Site 6) and 20m (Site 8) isobaths within the Mississippi Bight. Seasonal hypoxia acted as a regular periodic disturbance during the study period, although the magnitude and duration of hypoxia varied inter-annually. Macrobenthic metrics revealed seasonal hypoxia effects on secondary production potential and community maturity, which agrees with previous studies. In addition, metrics were notably higher at the 20m isobath during the latter half of the study period, following the Deepwater Horizon (DwH) oil spill. This study confirms hypoxia as a major driver affecting the function and structure of soft-bottom macrobenthos in the Mississippi Bight. PMID:26920427

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

    International Nuclear Information System (INIS)

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

  10. Spatio-temporal distribution of floating objects in the German Bight (North Sea)

    Science.gov (United States)

    Thiel, Martin; Hinojosa, Iván A.; Joschko, Tanja; Gutow, Lars

    2011-04-01

    Floating objects facilitate the dispersal of marine and terrestrial species but also represent a major environmental hazard in the case of anthropogenic plastic litter. They can be found throughout the world's oceans but information on their abundance and the spatio-temporal dynamics is scarce for many regions of the world. This information, however, is essential to evaluate the ecological role of floating objects. Herein, we report the results from a ship-based visual survey on the abundance and composition of flotsam in the German Bight (North Sea) during the years 2006 to 2008. The aim of this study was to identify potential sources of floating objects and to relate spatio-temporal density variations to environmental conditions. Three major flotsam categories were identified: buoyant seaweed (mainly fucoid brown algae), natural wood and anthropogenic debris. Densities of these floating objects in the German Bight were similar to those reported from other coastal regions of the world. Temporal variations in flotsam densities are probably the result of seasonal growth cycles of seaweeds and fluctuating river runoff (wood). Higher abundances were often found in areas where coastal fronts and eddies develop during calm weather conditions. Accordingly, flotsam densities were often higher in the inner German Bight than in areas farther offshore. Import of floating objects and retention times in the German Bight are influenced by wind force and direction. Our results indicate that a substantial amount of floating objects is of coastal origin or introduced into the German Bight from western source areas such as the British Channel. Rapid transport of floating objects through the German Bight is driven by strong westerly winds and likely facilitates dispersal of associated organisms and gene flow among distant populations.

  11. The recent arrival of the oceanic isopod Idotea metallica Bosc off Helgoland (German Bight, North Sea): an indication of a warming trend in the North Sea?

    Science.gov (United States)

    Franke, H.-D.; Gutow, L.; Janke, M.

    1998-09-01

    In 1988 a long-term study was started of the isopod fauna associated with surface drift material off Helgoland (German Bight, North Sea). In the summer of 1994 specimens of Idotea metallica Bosc were recorded for the first time. There is no evidence that this species has ever been present in the German Bight before. The samples contained males, both gravid and non-gravid females, and juveniles, indicating that the species reproduced successfully in the Helgoland region. Interbreeding of specimens from Helgoland and the western Mediterranean produced fertile off-spring. As a neustonic species, I. metallica shows a high natural capacity for dispersal. It thus seems unlikely that the arrival of the species in the North Sea resulted from an accidental introduction by man. We are probably witnessing an extension of the species’ geographical range by natural means of dispersal, as a response to recent changes in the ecological conditions of the German Bight. Temperature data measured by the Biologische Anstalt Helgoland since 1962 show that the last decade (except 1996) was characterized by unusually mild winters. Following the severe winter of 1996, I. metallica was again absent from the Helgoland region. After the subsequent mild winters (1997 and 1998), however, the species reappeared in the summer of 1998 with higher numbers than ever before. This suggests that the observed phenomena are closely connected with the recent temperature anomalies. I. metallica can be regarded as a potential immigrant to a warmer North Sea, and may be useful as a sensitive indicator of the predicted long-term warming trend.

  12. The dynamics of nutrient, toxic phytoplankton, nontoxic phytoplankton and zooplankton model

    Directory of Open Access Journals (Sweden)

    Hasnaa Fiesal Mohammed Hussien

    2016-02-01

    Full Text Available The objective of this paper is to study the dynamical behavior of an aquatic food web system. A mathematical model that includes nutrients, phytoplankton and zooplankton is proposed and analyzed. It is assumed that, the phytoplankton divided into two compartments namely toxic phytoplankton which produces a toxic substance as a defensive strategy against predation by zooplankton, and a nontoxic phytoplankton. All the feeding processes in this food web are formulating according to the Lotka-Volterra functional response. This model is represented mathematically by the set of nonlinear differential equations. The existence, uniqueness and boundedness of the solution of this model are investigated. The local and global stability conditions of all possible equilibrium points are established. The occurrence of local bifurcation and Hopf bifurcation are investigated. Finally, numerical simulation is used to study the global dynamics of this model.

  13. Diel vertical migration and spatial overlap between fish larvae and zooplankton in two tropical lakes, Brazil.

    Science.gov (United States)

    Picapedra, P H S; Lansac-Tôha, F A; Bialetzki, A

    2015-05-01

    The effect of fish larvae on the diel vertical migration of the zooplankton community was investigated in two tropical lakes, Finado Raimundo and Pintado lakes, Mato Grosso do Sul State, Brazil. Nocturnal and diurnal samplings were conducted in the limnetic region of each lake for 10 consecutive months from April 2008 to January 2009. The zooplankton community presented a wide range of responses to the predation pressure exerted by fish larvae in both environments, while fish larvae showed a typical pattern of normal diel vertical migration. Our results also demonstrated that the diel vertical migration is an important behaviour to avoid predation, since it reduces the spatial overlap between prey and potential predator, thus supporting the hypothesis that vertical migration is a defence mechanism against predation.

  14. Diseases and parasites of Baltic cod ( Gadus morhua ) from the Mecklenburg Bight to the Estonian coast

    DEFF Research Database (Denmark)

    Mellergaard, Stig; Lang, T.

    1999-01-01

    the Mecklenburg Bight in the southwest to the Estonian coast in the northeast of the Baltic Sea. Prevalences were highest in the western part, except for skeletal deformities, which were highest in the central part. The spatial distribution of pseudobranchial swellings, C. lingua and L. branchialis appeared...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  17. Summary of marine mammal and seabird surveys of the Southern California Bight area, 1975-1978. Volume III - investigators' reports. Part I - pinnipeds of the Southern California Bight. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bonnell, M.L.; Le Boeuf, B.J.; Pierson, M.O.; Dettman, D.H.; Farrens, G.D.

    1981-04-01

    This volume contains the findings of a three year study of the Pinnipedia of the Southern California Bight area. The distribution, abundance, movements, seasonality and reproductive status of the pinnipedia of the SBC area are discussed.

  18. 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 u

  19. Stratification of zooplankton in the northwestern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  20. Zooplankton composition in Dharamtar creek adjoining Bombay harbour

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  1. 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

  2. Flow disturbances generated by feeding and swimming zooplankton

    DEFF Research Database (Denmark)

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

    2014-01-01

    Interactions between planktonic organisms, such as detection of prey, predators, and mates, are often mediated by fluid signals. Consequently, many plankton predators perceive their prey from the fluid disturbances that it generates when it feeds and swims. Zooplankton should therefore seek...... 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...

  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. Rapid local adaptation mediates zooplankton community assembly in experimental mesocosms.

    Science.gov (United States)

    Pantel, Jelena H; Duvivier, Cathy; Meester, Luc De

    2015-10-01

    Adaptive evolution can occur over similar timescales as ecological processes such as community assembly, but its particular effects on community assembly and structure and their magnitude are poorly understood. In experimental evolution trials, Daphnia magna were exposed to varying environments (presence and absence of fish and artificial macrophytes) for 2 months. Then, in a common gardening experiment, we compared zooplankton community composition when either experimentally adapted or D. magna from the original population were present. Local adaptation of D. magna significantly altered zooplankton community composition, leading to a suppression of abundances for some zooplankton taxa and facilitation for others. The effect size of D. magna adaptation was similar to that of adding fish or macrophytes to mesocosms, two important drivers of zooplankton community structure. Our results suggest that substantial amounts of variation in community composition in natural systems may be unexplained if evolutionary dynamics are ignored. PMID:26251339

  5. Zooplankton ecology of the mangrove habitats of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

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

  6. 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.

    and that created by flowing through a cavitating element (orifice plates) on the microbes (zooplankton in sea water) is described. The experimental results are compared with modelling of cavitating conditions that includes cavity dynamics, turbulence generated...

  7. Next Generation Sequencing Reveals the Hidden Diversity of Zooplankton Assemblages

    OpenAIRE

    Lindeque, Penelope K.; Helen E Parry; Harmer, Rachel A.; Somerfield, Paul J.; Angus Atkinson

    2013-01-01

    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 ...

  8. Next Generation Sequencing Reveals the Hidden Diversity of Zooplankton Assemblages

    OpenAIRE

    Penelope K Lindeque; Parry, Helen E; Harmer, Rachel A.; Somerfield, Paul J; Atkinson, Angus

    2013-01-01

    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 c...

  9. On autumn zooplankton of Semipalatinsk test site water-bodies

    International Nuclear Information System (INIS)

    The autumn zooplankton in six water-bodies with mineralization diapason from 0.27 to 343.0 g/l was investigated. The species composition and number of structural characteristics were determined. The state of the zooplankton community by biodiversity and development indices is determined as normal. The observed increase of body dimensions in some species of Rotatoria and Microcrustacea requires the additional research. (author)

  10. Determinants of community structure of zooplankton in heavily polluted river ecosystems

    Science.gov (United States)

    Xiong, Wei; Li, Jie; Chen, Yiyong; Shan, Baoqing; Wang, Weimin; Zhan, Aibin

    2016-02-01

    River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants. However, it remains largely unknown how and to what extent many communities such as zooplankton are affected by these environmental stressors in river ecosystems. Here, we aim to determine major factors responsible for shaping community structure of zooplankton in heavily polluted river ecosystems. Specially, we use rotifers in the Haihe River Basin (HRB) in North China as a case study to test the hypothesis that species sorting (i.e. species are “filtered” by environmental factors and occur at environmental suitable sites) plays a key role in determining community structure at the basin level. Based on an analysis of 94 sites across the plain region of HRB, we found evidence that both local and regional factors could affect rotifer community structure. Interestingly, further analyses indicated that local factors played a more important role in determining community structure. Thus, our results support the species sorting hypothesis in highly polluted rivers, suggesting that local environmental constraints, such as environmental pollution caused by human activities, can be stronger than dispersal limitation caused by regional factors to shape local community structure of zooplankton at the basin level.

  11. Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages.

    Science.gov (United States)

    Dias, J D; Simões, N R; Bonecker, C C

    2012-02-01

    Fish farming in net cages causes changes in environmental conditions. We evaluated the resilience of zooplankton concerning this activity in Rosana Reservoir (Paranapanema River, PR-SP). Samples were taken near the net cages installed at distances upstream and downstream, before and after net cage installation. The resilience was estimated by the decrease in the groups' abundance after installing the net cages. The zooplankton community was represented by 106 species. The most abundant species were Synchaeta pectinata, S. oblonga, Conochilus coenobasis, Polyarthra dolichoptera and C. unicornis (Rotifera), Ceriodaphnia cornuta, Moina minuta, Bosmina hagmanni and C. silvestrii (Cladocera) and Notodiaptomus amazonicus (Copepoda). The resilience of microcrustaceans was affected in the growing points as this activity left the production environment for longer, delaying the natural ability of community responses. Microcrustaceans groups, mainly calanoid and cyclopoid copepods, had a different return rate. The net cage installation acted as a stress factor on the zooplankton community. Management strategies that cause fewer risks to the organisms and maximize energy flow may help in maintaining system stability. PMID:22437379

  12. The zooplankton community in the Greenland Sea: Composition and role in carbon turnover

    Science.gov (United States)

    Møller, Eva Friis; Nielsen, Torkel Gissel; Richardson, Katherine

    2006-01-01

    The micro- and mesozooplankton communities in surface waters of the Greenland Sea are described based on data from five cruises covering an annual cycle. Special emphasis is given to the summer period (June and August), prior to and after the descent of Calanus spp. Calanus spp. dominated the copepod community during the spring bloom and in the beginning of the summer. However, during the summer, there was a pronounced shift in the zooplankton composition in the euphotic zone. In contrast to what has been observed in other Arctic systems, smaller genera such as Pseudocalanus spp., O ncaea spp. and Oithona spp. became abundant and the total copepod biomass remained high after the Calanus spp. descended for hibernation. The peak protozooplankton biomass in the Greenland Sea (June) co-occurred with the peak in Calanus spp. Protozooplankton biomass then decreased during the summer. Growth of protozooplankton and grazing rates of the two dominating non- Calanus genera, Oithona and Pseudocalanus, were measured. For both copepod genera, protozooplankton constituted 40% or more of the diet, and maximum clearance was on prey items with an equivalent spherical diameter between 15 and 30 μm. The non- Calanus components of the zooplankton community were responsible for 70-99% of the total zooplankton grazing on phytoplankton during summer and were crucial for the recycling and respiration of primary production.

  13. Imazethapyr and imazapic, bispyribac-sodium and penoxsulam: Zooplankton and dissipation in subtropical rice paddy water

    Energy Technology Data Exchange (ETDEWEB)

    Reimche, Geovane B., E-mail: geovane_reimche@yahoo.com.br [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Machado, Sérgio L.O. [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Oliveira, Maria Angélica [Department of Biology, Federal University of Santa Maria, Santa Maria, RS (Brazil); Zanella, Renato; Dressler, Valderi Luiz; Flores, Erico M.M. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil); Gonçalves, Fábio F. [School of Chemistry and Food, Federal Foundation University of Rio Grande (FURG), 95500-000 Santo Antônio da Patrulha, RS (Brazil); Donato, Filipe F.; Nunes, Matheus A.G. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil)

    2015-05-01

    Herbicides are very effective at eliminating weed and are largely used in rice paddy around the world, playing a fundamental role in maximizing yield. Therefore, considering the flooded environment of rice paddies, it is necessary to understand the side effects on non-target species. Field experiment studies were carried out during two rice growing seasons in order to address how the commonly-used herbicides imazethapyr and imazapic, bispyribac-sodium and penoxsulam, used at recommended dosage, affect water quality and the non-target zooplankton community using outdoor rice field microcosm set-up. The shortest (4.9 days) and longest (12.2 days) herbicide half-life mean, estimated of the dissipation rate (k) is shown for imazethapyr and bispyribac-sodium, respectively. Some water quality parameters (pH, conductivity, hardness, BOD{sub 5}, boron, potassium, magnesium, phosphorus and chlorides) achieved slightly higher values at the herbicide treatment. Zooplankton community usually quickly recovered from the tested herbicide impact. Generally, herbicides led to an increase of cladocera, copepods and nauplius population, while rotifer population decreased, with recovery at the end of the experiment (88 days after herbicide treatment). - Highlights: • Selective herbicides in paddy rice fields, do not affect water quality. • Zooplankton communities show good response with herbicide dissipation. • The use of commercial herbicide mixture has strong effects on freshwater Rotifers.

  14. The zooplankton food web under East Antarctic pack ice - A stable isotope study

    Science.gov (United States)

    Jia, Zhongnan; Swadling, Kerrie M.; Meiners, Klaus M.; Kawaguchi, So; Virtue, Patti

    2016-09-01

    Understanding how sea ice serves zooplankton species during the food-limited season is crucial information to evaluate the potential responses of pelagic food webs to changes in sea-ice conditions in the Southern Ocean. Stable isotope analyses (13C/12C and 15N/14N) were used to compare the dietary preferences and trophic relationships of major zooplankton species under pack ice during two winter-spring transitions (2007 and 2012). During sampling, furcilia of Euphausia superba demonstrated dietary plasticity between years, herbivory when feeding on sea-ice biota, and with a more heterotrophic diet when feeding from both the sea ice and the water column. Carbon isotope signatures suggested that the pteropod Limacina helicina, small copepods Oithona spp., ostracods and amphipods relied heavily on sea-ice biota. Post larval E. superba and omnivorous krill Thysanoessa macrura consumed both water column and ice biota, but further investigations are needed to estimate the contribution from each source. Large copepods and chaetognaths overwintered on a water column-based diet. Our study suggests that warm and permeable sea ice is more likely to provide food for zooplankton species under the ice than the colder ice.

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

    Science.gov (United States)

    Hutchison, Evan R.; Neumeyer, Courtney H.; Gunderson, Matthew D.

    2016-01-01

    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 barrier to the entry

  16. Multibeam Mapping of the South Atlantic Bight: South Carolina 2005, a Proposed MPA on the Continental Shelf

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Fisheries laboratory in Panama City, Florida coordinated an acoustic survey at the new proposed Marine Protected Areas in the South Atlantic Bight area...

  17. Significant habitats and habitat complexes of the New York Bight watershed from 1971 to 1996 (NODC Accession 0071981)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report focuses on the identification and description of essential habitats of key species inhabiting the New York Bight watershed study area. The study area...

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

    Science.gov (United States)

    Paes, T A S V; Costa, I A S; Silva, A P C; Eskinazi-Sant'Anna, E M

    2016-06-01

    The aim of our study was to assess whether cyanotoxins (microcystins) can affect the composition of the zooplankton community, leading to domination of microzooplankton forms (protozoans and rotifers). Temporal variations in concentrations of microcystins and zooplankton biomass were analyzed in three eutrophic reservoirs in the semi-arid northeast region of Brazil. The concentration of microcystins in water proved to be correlated with the cyanobacterial biovolume, indicating the contributions from colonial forms such as Microcystis in the production of cyanotoxins. At the community level, the total biomass of zooplankton was not correlated with the concentration of microcystin (r2 = 0.00; P > 0.001), but in a population-level analysis, the biomass of rotifers and cladocerans showed a weak positive correlation. Cyclopoid copepods, which are considered to be relatively inefficient in ingesting cyanobacteria, were negatively correlated (r2 = - 0.01; P > 0.01) with the concentration of cyanotoxins. Surprisingly, the biomass of calanoid copepods was positively correlated with the microcystin concentration (r2 = 0.44; P > 0.001). The results indicate that allelopathic control mechanisms (negative effects of microcystin on zooplankton biomass) do not seem to substantially affect the composition of mesozooplankton, which showed a constant and high biomass compared to the microzooplankton (rotifers). These results may be important to better understand the trophic interactions between zooplankton and cyanobacteria and the potential effects of allelopathic compounds on zooplankton. PMID:26959954

  19. Variasi Geografik Kelimpahan Zooplankton di Perairan Terganggu, Kepulauan Seribu, Indonesia

    Directory of Open Access Journals (Sweden)

    Elok Faiqoh

    2015-10-01

    Full Text Available Zooplankton play a significant role in ecosystem as secondary producer. Climate change will potentially affect the abundance and global composition of zooplankton. This research aimed to study the geographical variation of zooplankton abundance relative to anthropogenic pressure. The research was conducted in April 2014 in area with presumably distinct anthropogenic level by its relative distance to the mainland of Jakarta. Samples were collected at Pramuka Island, Karang Beras Island, Kotok Island, and Sepa Island where subsequently lying to the nearest until furthest distance from mainland. Zooplankton samples were collected by towing the plankton net for 10 minutes for each site for three replicates. Abundance was obtained from Pramuka Island was 266698,214 ind/L, Karang Beras Island was 597363,1 ind/L, Kotok Island was 526447,8 ind/L and Sepa Island was 438225,3 ind/L. Overall, the closer to mainland, the richer nutrient and the more abundant zooplankton was conceived in the waters. Surprisingly, in Pramuka Island, the nearest island to mainland among other sites, had the lowest abundance of zooplankton although nutrient level was the richest among others.

  20. Towards an integrated view of benthic and pelagic processes in the southern North Sea (German Bight)

    Science.gov (United States)

    Friedrich, Jana; van Beusekom, Justus; Neumann, Andreas; Naderipour, Celine

    2015-04-01

    The North Sea can be classified as a semi-enclosed shelf on the western-European continent. Atlantic influences are mainly through the Fair Isle current Channel in the North, and through the Strait of Dover in the South. An anti-clockwise circulation prevails, driven by mainly semi-diurnal tides and winds. The German Bight is located in the south-eastern part of the North Sea, and is strongly influenced by continental rivers. The outflow from the rivers Scheldt, Maas and Rhine is carried towards the German Bight with the residual currents. The German rivers Ems, Weser and Elbe directly debouche into the German Bight. On the shallow shelf, the water column is completely mixed by tidal forces and wind, largely preventing downward flux of particles and instead fostering temporary deposition and resuspension, which influences benthic mineralization. Hence, complex interactions between pelagic and benthic processes occur. Previous budget calculations indicate that the nutrient inventory has to be processed several times to support observed primary production, and, depending on water depth; only 10-20% remineralisation occurs in sediments of the German Bight whereas about 50% of organic matter is remineralised in the sediments of the shallow Wadden Sea. In this presentation, we use in-situ and ex-situ field data on pelagic and benthic oxygen respiration and benthic nutrient fluxes to assess the intense mineralization activity in the German Bight, the partitioning of benthic and pelagic processes and the factors influencing organic matter mineralization. Measurements of pelagic oxygen respiration based on Winkler titration, in-situ benthic oxygen uptake measurements based on flux-chamber landers and ex-situ incubations of intact sediment cores revealed that benthic remineralisation rates are about an order of magnitude smaller than pelagic rates, in agreement with previous budget estimates. Both benthic and pelagic oxygen respiration show a strong seasonality; with higher

  1. Seasonal and interannual changes in zooplankton community in the coastal zone of the North-Eastern Black Sea.

    Science.gov (United States)

    Nikishina, A. B.; Arashkevich, E. G.; Louppova, N. E.; Soloviev, K. A.

    2009-04-01

    The phenological response of zooplankton community is a result of simultaneous effect of several factors: feeding conditions, predation abundance, periods of reproduction of common species and hydrodynamic regime. The Black sea ecosystem is one of the best studied in the world, otherwise there is still some illegibility about ecosystem functioning and especially about environmental factors influence on zooplankton dynamics. For the last twenty years pelagic system of the Black Sea has changed dramatically. The invasion of ctenophore Mnemiopsis leidyi in the middle of eighties caused significant decrease in zooplankton biomass. It also altered plankton structure and shifted periods of mass reproduction of the abundant species and biomass maximums. For instance, before the invasion of Mnemiopsis the maximum of zooplankton biomass was observed in autumn (data by A. Pasternak, 1983), and after that the maximum moved to the spring (data by V.S. Khoroshilov, 1999). The incursion of ctenophore Beroe ovata feeding on Mnemiopsis in the nineties has led to the enhancement of zooplankton community. Although the detailed analysis of seasonal zooplankton dynamics wasn't performed in the recent years. The object of our research was to study seasonal and interannual changes in zooplankton community in the coastal area of the North-Eastern Black Sea. Analysis of interannual, seasonal and spatial changes in zooplankton distribution, abundance and species composition along with age structure of dominant populations were performed based on investigations during 2005-2008 years in the North-Eastern Black Sea. Plankton samples were obtained monthly since June 2005 till December 2008. Plankton was collected at three stations at depths 25m, 50m and 500-1000m along the transect from the Blue Bay to the open sea. Sampling of gelatinous animals was conducted in parallel to the zooplankton sampling. Simultaneously with plankton sampling CTD data were obtained. The feeding conditions were

  2. Zooplankton structure and dynamics in two estuaries from the Atlantic coast in relation to multi-stressors exposure

    Science.gov (United States)

    Vieira, L. R.; Guilhermino, L.; Morgado, F.

    2015-12-01

    The aim of this research was to investigate the response of pelagic zooplankton to different levels of abiotic multi-stressors in the North Atlantic coast, taking advantage of the comparison of the communities of two adjacent estuaries with different levels of historical pollution (estuaries of Minho and Lima Rivers). The zooplankton community structure, composition and temporal variation were comparatively investigated for 15 months, using different net meshes. Several abiotic factors were measured in situ and water samples were simultaneously collected for determination of nutrients and chlorophyll a. The overall results revealed a diverse community represented by species that have been found in subtropical and temperate zones. Although the highest diversity was observed in the Lima estuary, supported by higher contributions of marine taxa, the total zooplankton biomass was found to be significantly higher in the Minho estuary. The salinity gradient differences between estuaries, associated to significant differences in water nutrients levels, were found to be the main forcing factors affecting micro and mesozooplankton. Considering the importance of the impacts resulting from abiotic variation on the basis of aquatic food webs, the present investigation represented a case-study, based in two contrasting estuaries, one strongly influenced by freshwater discharges (Minho estuary) and the other with higher salinity levels (Lima estuary), contributing to a better understanding of the effects of multi-stressors on pelagic zooplankton communities, providing useful information for studies related with climate change impacts, biogeography, conservation and providing data contributing to the improvement of pelagic fisheries management models.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-08-01

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

  4. MOCHA: A three dimensional climatology of salinity and temperature of the Middle Atlantic Bight

    Science.gov (United States)

    Fleming, N. E.; Wilkin, J. L.

    2013-05-01

    A 3-D climatology of the salinity and temperature of the Middle Atlantic Bight (MAB) is developed to provide a synthesis of observations and a tool for understanding the heat and freshwater budgets, and dynamics, of this area. 150 years of historical data are quality controlled and combined by weighted least squares to a 3-D grid encompassing the Middle Atlantic Bight and the Gulf of Maine, including Chesapeake Bay, Delaware Bay, and the Hudson River Estuary. Half degree grid spacing, along with weighted fitting in horizontal distance, vertical distance, time and bathymetry provide highly resolved maps for each month of the year that compare well to independent data sets. Features such as the MAB "Cold Pool", and the seasonal cycle of heating and cooling are clearly visible throughout the months.

  5. Coastal Ocean Observing System Elements for the Southern California Bight and Santa Monica

    OpenAIRE

    Gruber, Nicolas; Mcwilliams, James C.

    2004-01-01

    We propose to establish, maintain, and augment the sensors for UCLA's oceanographic mooring near the edge of the continental shelf in Santa Monica Bay; extensively sample the water quality within the surrounding region, and interpret the measurements in combination with satellite sensing and three-dimensional, fine-scale numerical simulations of the local region. This will be done in coordination with other proposed measurements in the Southern California Bight that collectively are establis...

  6. Coastal Ocean Observing System Elements for the Southern California Bight and Santa Monica Bay

    OpenAIRE

    Gruber, Nicolas; Mcwilliams, James C.

    2005-01-01

    We propose to establish, maintain, and augment the sensors for UCLA's oceanographic mooring near the edge of the continental shelf in Santa Monica Bay; extensively sample the water quality within the surrounding region; and interpret the measurements in combination with satellite sensing and three-dimensional, fine-scale numerical simulations of the local region. This will be done in coordination with other proposed measurements in the Southern California Bight that collectively are establish...

  7. Developing New Management Techniques for Sharks in the Drift Gillnet Fishery of the Southern California Bight

    OpenAIRE

    Graham, Jeffrey B.; Cartamil, Daniel P.

    2009-01-01

    The Southern California Bight (SCB) is a contiguous geographical region that extends from Point Conception, California to northern Baja California and west into the California Current. This region’s productive ecosystem supports various recreational and commercial fisheries, some of which target pelagic sharks. For example, the common thresher shark (Alopias vulpinus) comprises the largest commercial shark fishery in California waters (the California drift gillnet fishery, or CA-DGF. Mako sha...

  8. Contaminated sediments database for Long Island Sound and the New York Bight

    Science.gov (United States)

    Mecray, Ellen L.; Reid, Jamey M.; Hastings, Mary E.; Buchholtz ten Brink, Marilyn R.

    2003-01-01

    The Contaminated Sediments Database for Long Island Sound and the New York Bight provides a compilation of published and unpublished sediment texture and contaminant data. This report provides maps of several of the contaminants in the database as well as references and a section on using the data to assess the environmental status of these coastal areas. The database contains information collected between 1956-1997; providing an historical foundation for future contaminant studies in the region.

  9. Life history aspects of 19 rockfish species (Scorpaenidae: Sebastes) from the Southern California Bight

    OpenAIRE

    Love, Milton S.; Morris, Pamela; McCrae, Merritt; Collins, Robson

    1990-01-01

    The authors investigated various life history aspects of 19 rockfish species (Sebastes chlorostictus, S. constellatus, S. dalli, S. elongatus, S. ensifer, S. entomelas, S. flavidus, S. goodei, S. hopkinsi, S. levis, S. melanostomus, S. miniatus, S. ovalis, S. paucispinis, S. rosaceus, S. rosenblatti, S. rufus, s. saxicola, S. semicinctus) from the southern California Bight. These aspects included depth distribution, age-length relationships (of 7 species), length-weight relationships, size...

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

    Data.gov (United States)

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

  11. 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.

    Spatial and temporal variability in zooplankton production, composition and diversity in the coastal waters of Goa were studied. Zooplankton production was bimodal with primary peak during September-October and secondary peak during March...

  12. The Diel Vertical Distribution of Zooplankton in the Southeast Black Sea

    OpenAIRE

    ERKAN, Funda; GÜCÜ, Ali Cemal

    2000-01-01

    The diel changes in the vertical distribution of zooplankton in the southeast Black Sea were described in this study. The zooplankton were sampled using two different sampling methods throughout one day in October 1996 and July 1997 at the same station. The zooplankton counts, the length measurements and biomass estimates showed that the zooplankton in the southeast Black Sea is dominated by small organisms, among which Noctiluca scintillans is the dominant species. In the vertical distributi...

  13. Zooplankton abundance, biomass, and size structure in the coastal waters of the northeastern Mediterranean Sea

    OpenAIRE

    KURT, TUBA; POLAT, SEVİM

    2015-01-01

    Zooplankton was studied seasonally between 2009 and 2011 in İskenderun Bay in order to determine temporal variations in abundance, biomass, and size structure and their relationships with environmental factors. Zooplankton sampling was performed vertically using a WP-2 net (200-µm). A total of 30 zooplankton taxonomic groups were identified. Cladocera was the dominant group, and together with Copepoda and Appendicularia constituted approximately 90% of zooplankton. In respect to abundance and...

  14. Threshold foraging behaviour of basking sharks on zooplankton: life on an energetic knife-edge?

    OpenAIRE

    W.Sims, D.

    1999-01-01

    The minimum threshold foraging response of basking sharks has not been determined despite the widely held view that has been perpetuated in the literature for the past 45 years that this species cannot use low prey densities for net energy gain and so lives on an energetic 'knife-edge'. An early theoretical estimate suggested basking sharks would expend more energy collecting zooplankton at concentrations less than 1.36 g m-3 than could be obtained from it. This led to the claim that basking ...

  15. Distribution characteristics of zooplankton biomass in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    XU Zhaoli; CHAO Min; CHEN Yaqu

    2004-01-01

    On the basis of the data of oceanographic survey in the East China Sea in four seasons during 1997~2000 (23°30′~33°00′N,118°30′~ 128°E), the variation of total biomass and diet biomass of zooplankton and their spatial-temporal distribution and relationship with the fishing ground of Engraulisjaponicus are approached and analyzed. The results show that the average biomass is 65.32 mg/m3 in four seasons, autumn (86.18 mg/m3) being greater than summer (69.18 mg/m3) greater than s pring ( 55.67 mg/m3) greater than winter (50.33 mg/m3). The average value of diet zooplankton biomass is 40.9 mg/m3.The trends of horizontal distribution both in the total biomass and the diet biomass of zooplankton are similar. The high biomass region (250~500 mg/m3) is very limited, only accounting for 1% of the investigation area. Seasonal variation of the biomass is very remarkable in the west and north parts of East China Sea coastal waters ( 29°30′N, 125°E). The horizontal distribution of diet zooplankton depends on the abundance distribution of crustacean. The distribution of diet zooplankton is related to the fishing ground of Engraulis japonicus and the high-density area of young fish and larval. In spring, the central fishing ground of Engraulis japonicus (>100 kg/h) and the high-density area of young fish and larval (>100 individuals per net) are located at the same place of high-density (100~250 mg/m3)area of diet zooplankton in the middle-southern part of East China Sea or the edge of its waters.

  16. Distribution characteristics of zooplankton biomass in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    XU Zhaoli; CHAO Min; CHEN Yaqu

    2004-01-01

    On the basis of the data of oceanographic survey in the East China Sea in four seasons during 1997~2000 (23°30′~33°00′N,118°30′~ 128°E), the variation of total biomass and diet biomass of zooplankton and their spatial-temporal distribution and relationship with the fishing ground of Engraulis japonicus are approached and analyzed. The results show that the average biomass is 65.32 mg/m3 in four seasons, autumn (86.18 mg/m3) being greater than summer (69.18 mg/m3) greater than spring (55.67 mg/m3) greater than winter (50.33 mg/m3). The average value of diet zooplankton hiomass is 40.9 mg/m3.The trends of horizontal distribution both in the total biomass and the diet biomass of zooplankton are similar. The high biomass region (250~500 mg/m3) is very limited, only accounting for 1% of the investigation area. Seasonal variation of the biomass is very remarkable in the west and north parts of East China Sea coastal waters (29°30'N,125°E). The horizontal distribution of diet zooplankton depends on the abundance distribution of crustacean. The distribution of diet zooplankton is related to the fishing ground of Engraulis japonicus and the high-density area of young fish and larval. In spring, the central fishing ground of Engraulis japonicus (>100 kg/h) and the high-density area of young fish and larval (>100 individuals per net) are located at the same place of high-density (100~250 mg/m3)area of diet zooplankton in the middle-southern part of East China Sea or the edge of its waters.

  17. International research advances in marine zooplankton%国际海洋浮游动物研究进展

    Institute of Scientific and Technical Information of China (English)

    刘镇盛; 杜明敏; 章菁

    2013-01-01

      综述了国际上有关海洋浮游动物种群、群落结构、多样性及浮游动物对全球气候变化响应等方面研究进展。海洋浮游动物种类繁多,数量丰富,分布广泛,是海洋生态系统中最重要的生物类群。在海洋食物网中,浮游动物通过摄食浮游植物控制初级生产力,同时,又被更高营养阶层的动物(鱼、虾、鲸、海鸟等)捕食,充当次级生产者的角色,其群落结构、种群动态和物种多样性影响鱼类和其他海洋动物资源量,浮游动物是海洋食物网中关键环节。海洋生态系统动力学过程的关键环节是浮游生物的生物学和生态学过程,多项国际研究计划以生物多样性和年际变化趋势为研究重点并联系全球变化及响应,因此,浮游动物的研究已成为海洋生态研究的核心内容之一。国际上对浮游动物的研究主要集中在以下6个方向:(1)浮游动物生境、种群的分布和扩散动力学研究;(2)浮游动物的群落结构和多样性;(3)浮游动物的实验生态和现场受控生态研究;(4)浮游动物对全球气候变化的响应;(5)深海、南北极、低氧区等极端生境的浮游动物生态学研究;(6)浮游动物研究新技术和方法。%The recent advances in marine zooplankton research is reviews ,which includes research areas of marine zooplankton community structure and biodiversity and zooplankton's responses to global climate change .Marine zooplankton is rich in species numbers ,abundant and widely distributed ,and they play a vital role in marine eco-systems .In the marine food webs ,zooplankton controls primary production by grazing on phytoplankton .At the same time ,they are the prey of animals of higher trophic levels ,such as fish ,shrimp ,whales and seabirds ,acting as the role of secondary producers .The community structure ,population dynamics and species diversity of zoo-plankton

  18. 国际海洋浮游动物研究进展%International research advances in marine zooplankton

    Institute of Scientific and Technical Information of China (English)

    刘镇盛; 杜明敏; 章菁

    2013-01-01

      综述了国际上有关海洋浮游动物种群、群落结构、多样性及浮游动物对全球气候变化响应等方面研究进展。海洋浮游动物种类繁多,数量丰富,分布广泛,是海洋生态系统中最重要的生物类群。在海洋食物网中,浮游动物通过摄食浮游植物控制初级生产力,同时,又被更高营养阶层的动物(鱼、虾、鲸、海鸟等)捕食,充当次级生产者的角色,其群落结构、种群动态和物种多样性影响鱼类和其他海洋动物资源量,浮游动物是海洋食物网中关键环节。海洋生态系统动力学过程的关键环节是浮游生物的生物学和生态学过程,多项国际研究计划以生物多样性和年际变化趋势为研究重点并联系全球变化及响应,因此,浮游动物的研究已成为海洋生态研究的核心内容之一。国际上对浮游动物的研究主要集中在以下6个方向:(1)浮游动物生境、种群的分布和扩散动力学研究;(2)浮游动物的群落结构和多样性;(3)浮游动物的实验生态和现场受控生态研究;(4)浮游动物对全球气候变化的响应;(5)深海、南北极、低氧区等极端生境的浮游动物生态学研究;(6)浮游动物研究新技术和方法。%The recent advances in marine zooplankton research is reviews ,which includes research areas of marine zooplankton community structure and biodiversity and zooplankton's responses to global climate change .Marine zooplankton is rich in species numbers ,abundant and widely distributed ,and they play a vital role in marine eco-systems .In the marine food webs ,zooplankton controls primary production by grazing on phytoplankton .At the same time ,they are the prey of animals of higher trophic levels ,such as fish ,shrimp ,whales and seabirds ,acting as the role of secondary producers .The community structure ,population dynamics and species diversity of zoo-plankton

  19. VERMICOMPOST: QUALITY ORGANIC MANURE FOR ZOOPLANKTON PRODUCTION IN AQUACULTURE

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar

    2012-08-01

    Full Text Available Purpose of the present study was to evaluate the effect of vermicompost on water quality parameters of fish pond and zooplankton production. No significant effect on the physico-chemical properties of pond water were observed though the zooplankton population was better with significant difference in rotifers population (68.38% comparing with cow dung treated pond. Application of vermicompost as an organic manure in fish pond is not only better but also safe than the raw cow dung. This is excellent manure for nursery and rearing pond as it has a potential to produce good rotifers population.

  20. 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.

    Hazards", Spl. Vol. of IGC O.P. Varma, G.V. Rajamanickam & Eugene Wilson (eds.), Ind. Geol. Cong., 2010, pp. 199-207. 16 Metals in Coastal Zooplanktons - A Coastal Living Resource Hazard J.S. Paimpillil 1 , J. Thresiamma 2 , Rejomon George 2 & Vijay... too simplistic. The role of trace metals, such as iron or zinc in the growth of algae and zooplankton need to be looked into; after all, most land-based life forms, including humans, cannot survive without such metals in their diet. The most common...

  1. Coupling of wave and circulation models in coastal-ocean predicting systems: a case study for the German Bight

    Science.gov (United States)

    Staneva, Joanna; Wahle, Kathrin; Günther, Heinz; Stanev, Emil

    2016-06-01

    This study addresses the impact of coupling between wave and circulation models on the quality of coastal ocean predicting systems. This is exemplified for the German Bight and its coastal area known as the Wadden Sea. The latter is the area between the barrier islands and the coast. This topic reflects the increased interest in operational oceanography to reduce prediction errors of state estimates at coastal scales, which in many cases are due to unresolved non-linear feedback between strong currents and wind waves. In this study we present analysis of wave and hydrographic observations, as well as results of numerical simulations. A nested-grid modelling system is used to produce reliable nowcasts and short-term forecasts of ocean state variables, including waves and hydrodynamics. The database includes ADCP observations and continuous measurements from data stations. The individual and combined effects of wind, waves and tidal forcing are quantified. The performance of the forecast system is illustrated for the cases of several extreme events. The combined role of wave effects on coastal circulation and sea level are investigated by considering the wave-dependent stress and wave breaking parameterization. Also the response, which the circulation exerts on the waves, is tested for the coastal areas. The improved skill of the coupled forecasts compared to the non-coupled ones, in particular during extreme events, justifies the further enhancements of coastal operational systems by including wave effects in circulation models.

  2. The modulation of the seasonal cross-shelf sea level variation by the cold pool in the Middle Atlantic Bight

    Science.gov (United States)

    Sha, Jin; Jo, Young-Heon; Yan, Xiao-Hai; Liu, W. T.

    2015-11-01

    This study explores the influence of the cold pool in the Middle Atlantic Bight (MAB) to cross-shelf sea surface slope by fitting an annual harmonic to temperature and salinity profiles from 1993 to 2012 and compares to the 20 year averaged altimetry sea level anomaly (SLA). The consistency within the bottom temperature, thermal steric height, total steric height, and altimetry observation validates that the cold pool induces a depressed sea level in the middle shelf overlapping with the dominant surface seasonal cycles. Temporally, the cold pool pattern is most apparent in July and August as a result of magnitude competition between the thermal and haline steric height. In addition, Ensemble Empirical Mode Decomposition (EEMD) is employed to reconstruct the altimetry SLA and reveals the middle-shelf depression pattern from single year's SLA data. The locations of the SLA depression from 1993 to 2012 agree with the cold pool locations identified from in situ measurements, suggesting a promising application of altimetry SLA in the cold pool study. Conclusively, this study reveals the modulation of the cross-shelf sea level variation by the cold pool, and contributes to the understanding of the sea level response to water masses on the continental shelf.

  3. Short-term Variations of the Zooplankton Community Near the Straits of Messina (North-eastern Sicily): Relationships with the Hydrodynamic Regime

    Science.gov (United States)

    Zagami, G.; Badalamenti, F.; Guglielmo, L.; Manganaro, A.

    1996-05-01

    Zooplankton samples were collected near the Straits of Messina over two 24-h periods in May 1988 and January 1989. In this area, the complex system of currents which circulate through the Straits still affects both biotic and hydrological factors even near the shore. Copepoda, Cladocera, Chaetognatha and Appendicularia together with some meroplanktonic taxa make up the zooplankton assemblage collected during the two periods. The community structure changes greatly in terms of biomass and density during the 24-h cycle, and in terms of species composition between the two sampling months. The variability of biomass and density could be ascribed to the effect of the special current system in the area, whereas variations in species composition could be related to the seasonality demonstrated by the zooplankton community. These factors combined are responsible for the peculiar condition described in the paper.

  4. Virus-phytoplankton adhesion: a new WSSV transmission route to zooplankton

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pathogenicity of white spot syndrome virus (WSSV) to zooplankton species, rotifer Brachionus urceus (Linnaeus), copepod Acartia clausi (Giesbrecht) and mysid shrimp Neomysis awatschensis (Brandt), was estimated by immersion challenge and virus-phytoplankton adhesion route to investigate a potential new transmission route of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus-phytoplankton adhesion route, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus-phytoplankton adhesion route is a successful new transmission route of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

  5. Lake St. Clair zooplankton: Evidence for post-dreissena changes

    Science.gov (United States)

    David, K.A.; Davis, B.M.; Hunter, R.D.

    2009-01-01

    We surveyed the zooplankton of Lake St. Clair at 12 sites over ten dates from May to October 2000. Mean zooplankton density by site and date was 168.6 individuals/L, with Dreissena spp. veligers the most abundant taxon at 122.7 individuals/L. Rotifers, copepods, and cladocerans were far lower in mean abundance than in the early 1970s (rotifers, 20.9/L; copepods, 18.1/L; and cladocerans, 6.8/L). Species richness of zooplankton taxa in 2000 was 147, which was virtually unchanged from that of the first reported survey in 1894. Overall, the decline in abundance was greatest for rotifers (-90%) and about equal for cladocerans (-69%) and copepods (-66%). The decrease in abundance of Daphnia spp. was especially dramatic in Canadian waters. The decline in the southeastern region was significant for all three major groups of zooplankton, whereas in the northwestern region the decline was significant only for rotifers. From June to August 2000, Lake St. Clair open waters were numerically dominated by Dreissena spp. veligers, with a reduced abundance of rotifers and crustaceans compared to pre-Dreissena spp. surveys. Mean nutrient concentrations were not different from the 1970s, but Secchi depth (greater) and chlorophyll a concentration (lower) were. Disproportionate reduction in rotifer abundance is consistent with hypotheses implicating direct consumption by settled Dreissena spp. Reduction of crustaceans is likely due to more complex interactions including removal of nauplii as well as resource competition for phytoplankton.

  6. Distribution and abundance of zooplankton populations in Crater Lake, Oregon

    Science.gov (United States)

    Larson, G.L.; McIntire, C.D.; Buktenica, M.W.; Girdner, S.F.; Truitt, R.E.

    2007-01-01

    The zooplankton assemblages in Crater Lake exhibited consistency in species richness and general taxonomic composition, but varied in density and biomass during the period between 1988 and 2000. Collectively, the assemblages included 2 cladoceran taxa and 10 rotifer taxa (excluding rare taxa). Vertical habitat partitioning of the water column to a depth of 200 m was observed for most species with similar food habits and/or feeding mechanisms. No congeneric replacement was observed. The dominant species in the assemblages were variable, switching primarily between periods of dominance of Polyarthra-Keratella cochlearis and Daphnia. The unexpected occurrence and dominance of Asplanchna in 1991 and 1992 resulted in a major change in this typical temporal shift between Polyarthra-K. cochlearis and Daphnia. Following a collapse of the zooplankton biomass in 1993 that was probably caused by predation from Asplanchna, Kellicottia dominated the zooplankton assemblage biomass between 1994 and 1997. The decline in biomass of Kellicottia by 1998 coincided with a dramatic increase in Daphnia biomass. When Daphnia biomass declined by 2000, Keratella biomass increased again. Thus, by 1998 the assemblage returned to the typical shift between Keratella-Polyarthra and Daphnia. Although these observations provided considerable insight about the interannual variability of the zooplankton assemblages in Crater Lake, little was discovered about mechanisms behind the variability. When abundant, kokanee salmon may have played an important role in the disappearance of Daphnia in 1990 and 2000 either through predation, inducing diapause, or both. ?? 2007 Springer Science+Business Media B.V.

  7. Evaluation of Zooplankton in Hatchery Diets for Channel Catfish Fry

    Science.gov (United States)

    The efficacy of zooplankton as a supplemental hatchery diet for fry of channel catfish Ictalurus punctatus was evaluated. When a commercial diet is used as a reference, fry fed exclusively on zooplankton–either live or dried–performed poorly in their growth rate. However, when live or dried zooplan...

  8. An Updated Zooplankton Biodiversity of Turkish Inland Waters

    Directory of Open Access Journals (Sweden)

    M. Ruşen USTAOĞLU

    2015-12-01

    Full Text Available In this study, zooplankton biodiversity in Turkish inland waters is updated by literature review. In 2004, a total of 427 taxa belong to 229 rotifers, 92 cladocerans and 106 copepods have determined in a zooplankton checklist (Ustaoğlu 2004. Between 2004 and 2011, rotifer biodiversity raised from 229 to 341 taxa in the checklist (Ustaoğlu et al. 2012. By the increasing studies on the subject in recent years and as a consequence of reviewing 263 literature from the studies; 5 new genera (Ceratotrocha, Donneria, Octotrocha, Otostephanos, Stephanoceros and 76 taxa from rotifer fauna; 1 new genus (Kurzia and 11 taxa from cladoceran fauna; 13 new genera (Calacalanus, Mecynocera, Paracalanus, Lernaea, Oithona, Echinocamptus, Maraenobiotus, Leptocaris, Harpacticus, Heterolaophonte, Metis, Phyllognathopu, Kinnecaris and 35 taxa from copepod fauna have been added to the zooplankton fauna. As a result, the recent checklist of inland waters zooplankton of Turkey has 661 taxa which include 417 rotifers, 103 cladocerans and 141 copepods namely.

  9. Zooplankton and Karenia brevis in the Gulf of Mexico

    Science.gov (United States)

    Lester, Kristen M.; Heil, Cynthia A.; Neely, Merry B.; Spence, Danylle N.; Murasko, Susan; Hopkins, Thomas L.; Sutton, Tracey T.; Burghart, Scott E.; Bohrer, Richard N.; Remsen, Andrew W.; Vargo, Gabriel A.; Walsh, John J.

    2008-01-01

    Blooms of the toxic dinoflagellate Karenia brevis are common in the Gulf of Mexico, yet no in situ studies of zooplankton and K. brevis have been conducted there. Zooplankton abundance and taxonomic composition at non-bloom and K. brevis bloom stations within the Ecology of Harmful Algal Blooms (ECOHAB) study area were compared. At non-bloom stations, the most abundant species of zooplankton were Parvocalanus crassirostris, Oithona colcarva, and Paracalanus quasimodo at the 5-m isobath and P. quasimodo, O. colcarva, and Oikopleura dioica at the 25-m isobath. There was considerable overlap in dominance of zooplankton species between the 5 and 25-m isobaths, with nine species contributing to 90% of abundance at both isobaths. At stations within K. brevis blooms however, Acartia tonsa, Centropages velificatus, Temora turbinata, Evadne tergestina, O. colcarva, O. dioica, and P. crassirostris were dominant. Variations in abundance between non-bloom and bloom assemblages were evident, including the reduction in abundance of three key species within K. brevis blooms.

  10. Coprophagy in copepods and in a natural zooplankton community

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Kiørboe, Thomas

    5 % of the fecal pellet production in the upper 50 m was lost as flux below 50 m depth. Estimates of coprophagy rates showed, however, that the zooplankton community > 200 um could account for only a few percent of the fecal pellet loss. Thus, plankton organisms

  11. Narcotisation, fixation and preservation experiments with marine zooplankton

    NARCIS (Netherlands)

    Heyman, R.P.

    1981-01-01

    In this report narcotisation, fixation and preservation experiments with marine zooplankton are described. Narcotisation turns out to be useless for mixed plankton samples. M.S. 222 works well as narcotisation medium for organisms to be photographed. Fixation with 4% formalin proved to be a necessar

  12. 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.

    variations and ranged between 8.02 and 29.9% (x = 19.57 + or - 6.25). Values for carbohydrate content varied from 11.01 to 27.65% (x = 19.62 + or - 4.80). Higher accumulation of lipids in Antarctic zooplankton during phytoplankton blooms (austral summer...

  13. The ICES Working Group on Zooplankton Ecology: Accomplishments of the first 25 years

    Science.gov (United States)

    Wiebe, Peter H.; Harris, Roger; Gislason, Astthor; Margonski, Piotr; Skjoldal, Hein Rune; Benfield, Mark; Hay, Steve; O'Brien, Todd; Valdés, Luis

    2016-02-01

    The ICES Study Group on Zooplankton Ecology was created in 1991 to address issues of current and future concern within the field of zooplankton ecology. Within three years it became the ICES Working Group on Zooplankton Ecology (ICES WGZE) and this unique group in the world's oceanographic community has now been active for 25 years. This article reviews and synthesizes the products, and major accomplishments of the group. Achievements of the group, including the Zooplankton Methodology Manual, the Zooplankton Status Reports, and the International Zooplankton Symposia, have had an important impact on the wider field. Among the future issues that remain to be addressed by the group are the assessment of exploratory fisheries on zooplankton and micronekton species; further development of the zooplankton time-series; compilation and integration of allometric relationships for zooplankton species, and evaluation of new methodologies for the study of zooplankton distribution, abundance, physiology, and genetics. Marine science is an increasingly global undertaking and groups such as the ICES WGZE will continue to be essential to the advancement of understanding of zooplankton community structure and population dynamics in the world's oceans.

  14. Habitat heterogeneity determines climate impact on zooplankton community structure and dynamics.

    Directory of Open Access Journals (Sweden)

    Saskia A Otto

    Full Text Available Understanding and predicting species distribution in space and time and consequently community structure and dynamics is an important issue in ecology, and particularly in climate change research. A crucial factor determining the composition and dynamics of animal populations is habitat heterogeneity, i.e., the number of structural elements in a given locality. In the marine pelagic environment habitat heterogeneity is represented by the distribution of physical oceanographic parameters such as temperature, salinity and oxygen that are closely linked to atmospheric conditions. Little attention has been given, however, to the role of habitat heterogeneity in modulating the response of animal communities to external climate forcing. Here we investigate the long-term dynamics of Acartia spp., Temora longicornis, and Pseudocalanus acuspes, three dominant zooplankton species inhabiting different pelagic habitats in the Central Baltic Sea (CBS. We use the three copepods as indicator species for changes in the CBS zooplankton community and apply non-linear statistical modeling techniques to compare spatial population trends and to identify their drivers. We demonstrate that effects of climate variability and change depend strongly on species-specific habitat utilization, being more direct and pronounced at the upper water layer. We propose that the differential functional response to climate-related drivers in relation to strong habitat segregation is due to alterations of the species' environmental niches. We stress the importance of understanding how anticipated climate change will affect ecological niches and habitats in order to project spatio-temporal changes in species abundance and distribution.

  15. The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective

    DEFF Research Database (Denmark)

    Bramm, Mette Elisabeth; Lassen, Majbritt Kjeldahl; Liboriussen, Lone;

    2009-01-01

    in winter light conditions are needed in order to have a significant effect on the plankton community. The change in light occurring when such plankton communities move northwards in response to global warming will mostly be of modest importance for this lake type, at least for the rest of this century......1. Variations in the light regime can affect the availability and quality of food for zooplankton grazers as well as their exposure to fish predation. In northern lakes light is particularly low in winter and, with increasing warming, the northern limit of some present-day plankton communities may...... move further north and the plankton will thus receive less winter light. 2. We followed the changes in the biomass and community structure of zooplankton and phytoplankton in a clear and a turbid shallow lake during winter (November-March) in enclosures both with and without fish and with four...

  16. Size-based diel migration of zooplankton in mediterranean shallow lakes assessed from in situ experiments with artificial plants

    OpenAIRE

    Tavsanoglu, Ülkü Nihan; Brucet Balmaña, Sandra; Levi, Eti Ester; Bucak, Tuba; Bezirci, Gizem; Özen, Arda; Johansson, Liselotte S.; Jeppesen, Erik; Beklioglu, Meryem

    2015-01-01

    In warm lakes, fish aggregate within macrophytes, thereby weakening the role of these as a daytime refuge for zooplankton and altering the zooplankton size structure, predation pressure, and water clarity. To elucidate the role of macrophytes as a refuge for zooplankton and their effect on zooplankton size distribution, we established three sets of strandardized artificial plant beds in 11 lakes in Turkey with contrasting fish predation risk and turbidity. Zooplankton ...

  17. A seafloor crater in the German Bight and its effect on the benthos

    OpenAIRE

    Thatje, S.; Gerdes, Dieter; Rachor, Eike

    1999-01-01

    In 1963 a deep crater was formed about 65 m below sea level in the western part of the German Bight, due to a gas eruption caused by drilling carried out from the platform ŽMr. LouieŽ. The study area is situated in a sandy to muddy bottom area inhabited by an Amphiura-filiformis-association (sensu Salzwedel et al., 1985). The crater, sometimes called ŽFigge-MaarŽ, functions as a sediment-trap, concentrating particles and organisms from the water column, thus leading to extreme sedimentation r...

  18. The recovery of benthos following the impact of low oxygen content in the German Bight

    Science.gov (United States)

    Niermann, U.; Bauerfeind, E.; Hickel, W.; Westernhagen, H. V.

    The oxygen deficiency in the German Bight and in Danish waters 1981-1983 with ensuing benthos mortality was the reason for studying the development and re-establishment of the macrofauna in the following years. These years, from 1984-1987, exhibited more favourable oxygen conditions. The macrofauna of this region with its predominantly sandy substrate belongs to the Tellina fabula community. It is dominated by regular seasonal and ephemeral species such as Spio filicornis, Phoronis spec., Spiophanes bombyx and Lanice conchilega. In 1983, a year with exceptionally low oxygen content in bottom waters (Echinocardium cordatum and crustaceans have been observed since 1984 in larger numbers.

  19. A seafloor crater in the German Bight and its effects on the benthos

    OpenAIRE

    Thatje, S.; Gerdes, D.; Rachor, E.

    1999-01-01

    In 1963 a deep crater was formed about 65 m below sea level in the western part of the German Bight, due to a gas eruption caused by drilling carried out from the platform ’Mr. Louie'. The study area is situated in a sandy to muddy bottom area inhabited by an Amphiura filiformis association (sensu Salzwedel et al. 1985). The crater, sometimes called ’Figge-Maar', functions as a sediment trap, concentrating particles and organisms from the water column, thus leading to extreme sedimentation ra...

  20. Strongly-sheared wind-forced currents in the nearshore regions of the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt; Robertson, George L.

    2015-01-01

    Contrary to many previous reports, winds do drive currents along the shelf in the central portion of the Southern California Bight (SCB). Winds off Huntington Beach CA are the dominant forcing for currents over the nearshore region of the shelf (water depths less than 20 m). Winds control about 50–70% of the energy in nearshore alongshelf surface currents. The wind-driven current amplitudes are also anomalously high. For a relatively weak 1 dyne/cm2 wind stress, the alongshelf surface current amplitudes in this region can reach 80 cm/s or more. Mid-depth current amplitudes for the same wind stress are around 30–40 cm/s. These wind-driven surface current amplitudes are much larger than previously measured over other nearshore shelf regions, perhaps because this program is one of the few that measured currents within a meter of the surface. The near-bed cross-shelf currents over the nearshore region of the Huntington Beach shelf have an Ekman response to winds in that they upwell (downwell) for down (up) coast winds. This response disappears further offshore. Hence, there is upwelling in the SCB, but it does not occur across the entire shelf. Subthermocline water in the nearshore region that may contain nutrients and plankton move onshore when winds are southeastward, but subthermocline water over the shelf break is not transported to the beach. The currents over the outer shelf are not predominately controlled by winds, consistent with previous reports. Instead, they are mainly driven by cross-shelf pressure gradients that are independent of local wind stress.

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

    Directory of Open Access Journals (Sweden)

    Sónia Cotrim Marques

    2014-05-01

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

  2. Diel vertical migration and distribution of zooplankton in a tropical Brazilian reservoir

    Directory of Open Access Journals (Sweden)

    Ana M. A. da Silva

    2009-03-01

    Full Text Available Diel vertical migration of zooplankton is a strategy usually employed to reduce the risk of predation, and it can also be associated with the environmental day/night shifts, particularly of light and temperature. The aim of this study was to identify the diel patterns of zooplankton vertical migration and their relationship to the environmental variables in a shallow reservoir in northeastern Brazil. Water samples were taken at a single five-meter depth sampling station (Subsurface, 50% Io, 1% Io and Bottom at four-hour intervals over a period of 24 hours. Two Cladocera species (Moina minuta and Diaphanosoma spinulosum and one Copepoda species (Notodiaptomus cearensis showed similar patterns of nocturnal migration, staying at the bottom during the day and rising toward the surface in the afternoon and during the night. Brachionus falcatus and Hexarthra mira (Rotifera showed no patterns of vertical migration and their vertical distributions were relatively homogenous. Environmental variables were poorly correlated to the species distribution, suggesting that other mechanisms may be responsible of inducing vertical migration.

  3. 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.

  4. A seasonal comparison of zooplankton communities in the Kara Sea - With special emphasis on overwintering traits

    Science.gov (United States)

    Kosobokova, Ksenia Nikolaevna; Hirche, Hans-Juergen

    2016-06-01

    Siberian marginal seas cover large parts of the marine Arctic and host unique zooplankton communities. Detailed knowledge of their community structure and life history traits is a prerequisite to predict their response to ongoing and future climate and anthropogenic changes although winter data is extremely rare. Here data are presented from winter samples (February and April) in four biogeographic regions of the Kara Sea. Comparison of community composition and zooplankton abundance/biomass with data collected during summer showed lower diversity in winter, mainly due to the absence of freshwater species. In contrast to many other northern regions, seasonal biomass differences were relatively small. Year-round high biomass is maintained through a large share of small copepod species and constantly high share of the chaetognath Parasagitta elegans. An advanced state of gonad maturation and reproduction was observed in winter in herbivorous, omnivorous, and carnivorous species, e.g. the copepods Calanus glacialis, Drepanopus bungei, Limnocalanus macrurus, Oithona similis, Pseudocalanus major, Pseudocalanus minutus/acuspes, Paraeuchaeta glacialis, Microcalanus pygmaeus, and euphausiids, hydromedusae, and pteropods. Meroplanktonic larvae of nudibranchia, polychaeta and bivalvia were also registered. Close to the Yenisei mouth, abundance of eggs and larvae of various taxa exceeded older stages. Our data show that the brackish-water zone of the Kara Sea hosts specific communities with omnivorous species efficiently exploiting local resources during the winter and utilizing them for winter reproduction.

  5. 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

  6. Continental shelf processes affecting the oceanography of the South Atlantic Bight. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Pietrafesa, L.J.

    1978-03-01

    The objectives of the project were to determine the physical/dynamical processes controlling/affecting the distribution of phytoplankton nutrients on the continental shelf in the South Atlantic Bight. The initial objectives were to determine the short term, i.e., 2 to 10 day and longer term flux of nutrients onto the continental shelf. This is clearly related to the more general problem of combined physical and biogenic control of phytoplankton nutrients. During the period from June, 1975 to March, 1978 the study of the continental shelf processes affecting the oceanography of the South Atlantic Bight has been principally involved with a substantial, coordinated field effort. The success of the data acquisition phase of the program has now required an intensive data analysis phase which has been slowly increasing in effort. Emphasis is placed on the main phase of the field program, located in Onslow Bay, which has beel completed and the data are being analyzed. During the three-year period 20 cruises were made into the Carolina Capes area and samples were collected. A list is included of some 100 publications during the period.

  7. Geology and geochemistry of the Geyser Bight Geothermal Area, Umnak Island, Aleutian Islands, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Nye, C.J. (Alaska Univ., Fairbanks, AK (USA). Geophysical Inst. Alaska Dept. of Natural Resources, Fairbanks, AK (USA). Div. of Geological and Geophysical Surveys); Motyka, R.J. (Alaska Dept. of Natural Resources, Juneau, AK (USA). Div. of Geological and Geophysical Surveys); Turner, D.L. (Alaska Univ., Fairbanks, AK (USA). Geophysical Inst.); Liss, S.A. (Alaska Dept. of Natural Resources, Fairba

    1990-10-01

    The Geyser Bight geothermal area is located on Umnak Island in the central Aleutian Islands. It contains one of the hottest and most extensive areas of thermal springs and fumaroles in Alaska, and is only documented site in Alaska with geysers. The zone of hot springs and fumaroles lies at the head of Geyser Creek, 5 km up a broad, flat, alluvial valley from Geyser Bight. At present central Umnak is remote and undeveloped. This report describes results of a combined program of geologic mapping, K-Ar dating, detailed description of hot springs, petrology and geochemistry of volcanic and plutonic rock units, and chemistry of geothermal fluids. Our mapping documents the presence of plutonic rock much closer to the area of hotsprings and fumaroles than previously known, thus increasing the probability that plutonic rock may host the geothermal system. K-Ar dating of 23 samples provides a time framework for the eruptive history of volcanic rocks as well as a plutonic cooling age.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  9. Marine zooplanktonic diversity: a view from the South Atlantic

    OpenAIRE

    Boltovskoy, D.; Correa, N.; Boltovskoy, A.

    2002-01-01

    Approximately 7000 marine zooplanktonic species have been described so far for the World Ocean; in the South Atlantic the presence of 40% of these has been confirmed, and an additional 20-30% are expected to be recorded in the future. The overall number of described species is very low when compared with other communities, and yet it may not be too far from the final, complete inventory. Very ample geographic distributional ranges, compositional similarity between the major oceanic basins, an...

  10. Flow disturbances generated by feeding and swimming zooplankton.

    Science.gov (United States)

    Kiørboe, Thomas; Jiang, Houshuo; Gonçalves, Rodrigo Javier; Nielsen, Lasse Tor; Wadhwa, Navish

    2014-08-12

    Interactions between planktonic organisms, such as detection of prey, predators, and mates, are often mediated by fluid signals. Consequently, many plankton predators perceive their prey from the fluid disturbances that it generates when it feeds and swims. Zooplankton should therefore seek 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)). As a result, the spatial extension of the fluid disturbance produced by swimmers is an order of magnitude smaller than that produced by feeders at similar Reynolds numbers. The "quiet" propulsion of swimmers is achieved either through swimming erratically by short-lasting power strokes, generating viscous vortex rings, or by "breast-stroke swimming." Both produce rapidly attenuating flows. The more "noisy" swimming of those that are constrained by a need to simultaneously feed is due to constantly beating flagella or appendages that are positioned either anteriorly or posteriorly on the (cell) body. These patterns transcend differences in size and taxonomy and have thus evolved multiple times, suggesting a strong selective pressure to minimize predation risk. PMID:25071196

  11. Zooplankton fecal pellets link fossil fuel and phosphate deposits

    Science.gov (United States)

    Porter, K.G.; Robbins, E.I.

    1981-01-01

    Fossil zooplankton fecal pellets found in thinly bedded marine and lacustrine black shales associated with phosphate, oil, and coal deposits, link the deposition of organic matter and biologically associated minerals with planktonic ecosystems. The black shales were probably formed in the anoxic basins of coastal marine waters, inland seas, and rift valley lakes where high productivity was supported by runoff, upwelling, and outwelling. Copyright ?? 1981 AAAS.

  12. 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

  13. Zooplankton diversity across three Red Sea reefs using pyrosequencing

    OpenAIRE

    John K Pearman; Mohsen M El-Sherbiny; Lanzén, Anders; Al-Aidaroos, Ali M.; Irigoien, Xabier

    2014-01-01

    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 9...

  14. Zooplankton diversity across three Red Sea reefs using pyrosequencing

    OpenAIRE

    John Kenneth Pearman; Mohsen M El-Sherbiny; Anders eLanzén; Ali eAl-Aidaroos; Xabier eIrigoien

    2014-01-01

    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 utilised 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 9...

  15. Studies on the zooplankton of the deep subalpine Lake Garda.

    Directory of Open Access Journals (Sweden)

    Luigi NASELLI-FLORES

    1999-02-01

    Full Text Available The specific composition and seasonal dynamics of the zooplankton of Lake Garda have been studied through monthly surveys in two annual cycles (December 1994-November 1995 and January-December 1997. The assemblage is largely dominated by Copipodiaptomus steueri, a typical calanoid presently identified in deep (Garda, Iseo and shallow lakes of NE Italy and in the hinterland of the central Adriatic region (Dalmatia and Marche Region. Cladocerans and the smaller rotifers represent a significant component of the zooplankton from spring to autumn. A re-examination of the results obtained in previous studies does not seem to demonstrate substantial shifts in the composition of the dominant species. The only documentable and consolidated differences are constituted by the disappearance of Sida crystallina since the '50s and the appearance of new rotifers since the '70s and the '80s. It is stressed that, owing to the fragmentation of the available studies and the use of different methodologies, the qualitative and quantitative modifications of the zooplankton should be interpreted with special caution, requiring further in-depth and continuous monitoring for the meaning they could have as possible signs of modifications of the trophic structure of the lake. However, the results of the comparison of the different investigations do not seem to contrast with the substantial stability of the oligo-mesotrophic character of the lake formally documented since the '70s.

  16. Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency.

    Science.gov (United States)

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

    2016-01-01

    Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous zooplankton is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was zooplankton was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton. PMID:27510848

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

    Directory of Open Access Journals (Sweden)

    Nicoletta RICCARDI

    1999-02-01

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

  18. 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.

  19. Taxonomy, distribution, and ecology of crustacean zooplankton in trough waters of Ankara (Turkey)

    OpenAIRE

    BAŞAK, Elif; Aygen, Cem; KÜLKÖYLÜOĞLU, OKAN

    2014-01-01

    Troughs are one of the main components of villages in Turkey. They are constructed by converting springs or underground waters. Until now, there has been no extensive study investigating the composition and diversity of trough zooplankton species. In order to contribute knowledge on the zooplanktons in troughs, 142 troughs were randomly sampled from 17 districts in Ankara Province between 22 June and 3 July 2011. A total of 18 zooplanktons including 11 Copepoda and 7 Cladocera species were de...

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

    OpenAIRE

    Nishida Mutsumi; Hashiguchi Yasuyuki; Machida Ryuji J; Nishida Shuhei

    2009-01-01

    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 ...

  1. Aspects of the ecology of the crustacean zooplankton in the Sanyati Basin, Lake Kariba

    OpenAIRE

    Marshall, B.E.

    1980-01-01

    Investigations on the zooplankton in Lake Kariba were carried out as part of a broader programme investigating components of the sardine, Limnothrissa miodon, food chain and factors affecting their productivity. This report deals mainly with the crustacean zooplankton, Bosmina longirostris and Mesocyclops leuckarti, which are the most important species in the sardine's diet. Factors which influence the number and distribution of the zooplankton are discussed. The relationship between the zoop...

  2. Growth of Barents Sea capelin (Mallotus villosus) in relation to zooplankton abundance

    OpenAIRE

    Gjøsæter, Harald; Dalpadado, Padmini; Hassel, Arne

    2002-01-01

    Because capelin feed on zooplankton, the availability of the latter may be a limiting factor for capelin growth in at least some areas and at certain times. It was therefore hypothesized that a relationship exists between capelin growth and zooplankton biomass either in the same year or in the previous autumn. Capelin growth in a given year was more closely correlated with the estimate of zooplankton abundance in the previous autumn than with that in the present autumn. Growth of the youngest...

  3. Methane and zooplankton in the epilimnion of Lake Fukami-ike

    OpenAIRE

    Suda, Hiromi; FUNAHASHI, Junko; Yagi, Akihiko

    2004-01-01

    Accumulations of bubbled and dissolved methane concentrations in rpilimnion have been frequently observed in Lake Fukami-ike. Based on the idea that the feeding activities of living zooplankton contribute to the methane concentrations in the lake, we examined wheter investigate live zooplankton evolve methane as a consequence of their feeding activities. Dissolved methane concentrations were higher after 6 hours in the samples of zooplankton only. This result might be support the idea that th...

  4. Bacteria of the γ-Subclass Proteobacteria Associated with Zooplankton in Chesapeake Bay

    OpenAIRE

    Heidelberg, J. F.; Heidelberg, K. B.; Colwell, R R

    2002-01-01

    The seasonal abundance of γ-subclass Proteobacteria, Vibrio-Photobacterium, Vibrio cholerae-Vibrio mimicus, Vibrio cincinnatiensis, and Vibrio vulnificus in the Choptank River of Chesapeake Bay associated with zooplankton was monitored from April to December 1996. Large (>202-μm) and small (64- to 202-μm) size classes of zooplankton were collected, and the bacteria associated with each of the zooplankton size classes were enumerated by fluorescent oligonucleotide direct count. Large populatio...

  5. Zooplankton Seasonal Abundance and Vertical Distribution of Highly Alkaline Lake Burdur, Turkey

    OpenAIRE

    Gülle, Iskender; Turna, Ismail Ibrahim; Güçlü, Salim Serkan; Gülle, Pinar; Güçlü, Zekiye

    2010-01-01

    During the period from December 2003 to November 2004 a study has been held to examine the water quality and zooplankton of highly alkaline Lake Burdur. The lake showed thermal stratification between June and October. Six zooplankton taxa were determined, Hexarthra fennica, Brachionus plicatilis from Rotifera and Arctodiaptomus burduricus from Copepoda were the dominant species. Average zooplankton density was 399,074 ind.m-3 and they were 51% H. fennica, 9% B. plicatilis and 40% A. burdu...

  6. Structure and function of zooplankton colonization in twelve new experimental ponds

    OpenAIRE

    Jenkins, David Glenn

    1990-01-01

    This study examined the structural and functional development of zooplankton communities in 12 new experimental ponds for one year and tested four predictions derived from the Random Placement Hypothesis (Coleman 1981). Physico-chemistry, zooplankton colonization dynamics, zooplankton community structure and function were analyzed every two weeks from 5 February 1988 to 10 February 1989. Ponds varied in physico-chemistry at points in time but followed similar patter...

  7. Abundance and Distribution of Zooplankton in CoastalArea of Gokceada Island (Northern Aegean Sea)

    OpenAIRE

    Tarkan, Abmet Nuri

    2000-01-01

    Abstract This study was carried out in order to determine population of zooplankton in the coastal waters of Gokgeada. At the 10 stations of those depths ranging from 20 in to 30 in, the measurements of temperature, salinity and oxygen were made, and zooplankton samples were collected vertically and horizontally using plankton nets. In the neritic waters of the island, the effects of the Black Sea waters through Dardanelles were observed and zooplankton species of the Black Sea found. F...

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

    OpenAIRE

    Neda Fazeli; Ahmad Savari; Seyed Mohamad Bagher Nabavi; Rasool Zare

    2014-01-01

    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...

  9. Community structure of zooplankton in the main entrance of Bahia Magdalena, Mexico during 1996

    OpenAIRE

    Gómez Gutiérrez, Jaime; Palomares García, José Ricardo; Hernández Trujillo, Sergio; Carballido Carranza, Azucena

    2001-01-01

    The zooplankton community structure, including copepods, euphausiids, chaetognaths, and decapod larvae, was monitored during six circadian cycles using Bongo net (500 *m mesh net) samples from Bahía Magdalena, on the southwest coast of Baja California, México. Samples were obtained during three oceanographic surveys (March, July, and December 1996) to describe the changes in the zooplankton community structure throughout the main mouth of Bahía Magdalena. The zooplankton community structure s...

  10. Effects on zooplankton of a warmer ocean: Recent evidence from the Northeast Pacific

    Science.gov (United States)

    Mackas, David L.; Batten, Sonia; Trudel, Marc

    2007-10-01

    The consequences for pelagic communities of warming trends in mid and high latitude ocean regions could be substantial, but their magnitude and trajectory are not yet known. Environmental changes predicted by climate models (and beginning to be confirmed by observations) include warming and freshening of the upper ocean and reduction in the extent and duration of ice cover. One way to evaluate response scenarios is by comparing how “similar” zooplankton communities have differed among years and/or locations with differing temperature. The subarctic Pacific is a strong candidate for such comparisons, because the same mix of zooplankton species dominates over a wide range of temperature climatologies, and observations have spanned substantial temperature variability at interannual-to-decadal time scales. In this paper, we review and extend copepod abundance and phenology time series from net tow and Continuous Plankton Recorder surveys in the subarctic Northeast Pacific. The two strongest responses we have observed are latitudinal shifts in centers of abundance of many species (poleward under warm conditions), and changes in the life cycle timing of Neocalanus plumchrus in both oceanic and coastal regions (earlier by several weeks in warm years and at warmer locations). These zooplankton data, plus indices of higher trophic level responses such as reproduction, growth and survival of pelagic fish and seabirds, are all moderately-to-strongly intercorrelated (∣ r∣ = 0.25-0.8) with indices of local and basin-scale temperature anomalies. A principal components analysis of the normalized anomaly time series from 1979 to 2004 shows that a single “warm-and-low-productivity” vs. “cool-and-high-productivity” component axis accounts for over half of the variance/covariance. Prior to 1990, the scores for this component were negative (“cool” and “productive”) or near zero except positive in the El Niño years 1983 and 1987. The scores were strongly and

  11. ECOLOGICAL STUDIES ON ZOOPLANKTON OF THE WEST LAKE AND THE INFLOWS

    OpenAIRE

    Li, Gouguo; Wei, Chongde; Zhou, Hong; Pei, Hongping

    1999-01-01

    Zooplankton ecology of the West Lake and the streams that flow into the lake were investigated during January-December 1995. Protozoans were the predominant group among 252 species of zooplankton, accounting for 50.4% of the total number. Due to the seasonal variations in density and biomass of zooplankton, were studied. Changqiao stream recorded the highest density of zooplankton among seven sampling points, with an average of 10,710 inds./L. The lowest density found was Jinsha stream (886 i...

  12. 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.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.

    of the world's oceans. High zooplankton production was reported by Panikkar and Rao (1973) and Smith (1982) in Somali upwelling regions, mostly during the period of the southwest monsoon. Several reports are available on the zooplankton of the eastern Arabian..., West Coast of India. Indian Journal of Marine Sciences 25(3): 26S- 273. Panikkar, N.K. and Rao, T.S.S. 1973. Zooplankton investigations in Indian waters and the role of the Indian Ocean Biological Centre. Handbook to the International zooplankton...

  14. 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 < 0.001). Sound speed contrast (h) was measured for euphausiids and pelagic decapods (S. similis) and it varied between taxa. The mean and standard deviation for euphausiid sound speed were 1.019 +/- 0.009. Euphausiid mass was calculated from density measurements and volume, and a relationship between euphausiid mass and length was produced. We determined that euphausiid from volumes could be accurately estimated two dimensional measurements of animal body shape, and that biomass (or biovolume) could be accurately calculated from digital photographs of animals. Density contrast (g) was measured for zooplankton, pieces of hake flesh, myctophid flesh, and of the following Humboldt squid body parts: mantle, arms, 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

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

    Directory of Open Access Journals (Sweden)

    Letizia GARIBALDI

    2009-02-01

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

  16. NOAA TIFF Image - 10m Bathymetric Rugosity, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ship Nancy Foster - (2009), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 10x10 meter cell size representing the rugosity of several deep coral priority areas off the South Atlantic Bight,...

  17. NOAA TIFF Image - 10m Bathymetric Rugosity, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ron Brown - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 10x10 meter cell size representing the rugosity of several deep coral priority areas off the South Atlantic Bight,...

  18. NOAA TIFF Image - 30m Backscatter, South Atlantic Bight - Deep Coral Priority Areas - Navy Pathfinder - (2003), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the bathymetry of several deep coral priority areas off the South Atlantic Bight,...

  19. Temperature and salinity profile data collected by CTD in the Mid-Atlantic Bight from 2/4/1999 - 2/14/2000 (NODC Accession 0000063)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected using CTD casts in the Mid-Atlantic Bight from 04 February 1999 to 14 February 2000.

  20. NOAA TIFF Image - 10m Multibeam Bathymetry, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ship Nancy Foster - (2009), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 10x10 meter cell size representing the bathymetry of several deep coral priority areas off the South Atlantic Bight,...

  1. NOAA TIFF Image - 10m Multibeam Bathymetry, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ship Nancy Foster - (2007), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 10x10 meter cell size representing the bathymetry of several deep coral priority areas off the South Atlantic Bight,...

  2. NOAA TIFF Image - 30m Multibeam Bathymetry, South Atlantic Bight - Deep Coral Priority Areas - Navy Pathfinder - (2003), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the bathymetry of several deep coral priority areas off the South Atlantic Bight,...

  3. NOAA TIFF Image - 30m Rugosity, South Atlantic Bight - Deep Coral Priority Areas - Navy Pathfinder - (2003), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the bathymetry of several deep coral priority areas off the South Atlantic Bight,...

  4. A high resolution water level forecast for the German Bight

    Science.gov (United States)

    Niehüser, Sebastian; Dangendorf, Sönke; Arns, Arne; Jensen, Jürgen

    2016-04-01

    Many coastal regions worldwide are potentially endangered by storm surges which can cause disastrous damages and loss of life. Due to climate change induced sea level rise, an accumulation of such events is expected by the end of the 21th century. Therefore, advanced storm surge warnings are needed to be prepared when another storm surge hits the coast. In the shallow southeastern North Sea these storm surge warnings are nowadays routinely provided for selected tide gauge locations along a coastline through state-of-the-art forecast systems, which are based on a coupled system of empirical tidal predictions and numerical storm surge forecasts. Along the German North Sea coastline, the Federal Maritime and Hydrographic Agency in cooperation with the German Weather Service is responsible for the storm surge warnings. They provide accurate, high frequency and real-time water level forecasts for up to six days ahead at selected tide gauge sites via internet, telephone and broadcast. Since water levels along the German North Sea coastline are dominated by shallow water effects and a very complex bathymetric structure of the seabed, the pointwise forecast is not necessarily transferable to un-gauged areas between the tide gauges. Here we aim to close this existing gap and develop water level forecasts with a high spatial (continuously with a resolution of at least 1 kilometer) as well as a high temporal (at least 15-minute values) resolution along the entire German North Sea coastline. We introduce a new methodology for water level forecasts which combines empirical or statistical and numerical models. While the tidal forecast is performed by non-parametric interpolation techniques between un-gauged and gauged sites, storm surges are estimated on the basis of statistical/empirical storm surge formulas taken from a numerical model hindcast. The procedure will be implemented in the operational mode forced with numerical weather forecasts.

  5. Biological processes in the water column of the south Atlantic bight. Annual progress report, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhoefer, G.A.; Yoder, J.A.

    1980-01-31

    A study of Summer Intrusions, consisting of 7 weekly cruises between 28/sup 0/50' and 31/sup 0/00'N, was conducted from July 5 to August 17, 1979. Additional chlorophyll and nutrient samples were collected in the study area during the week of August 23. Our goal was to follow a newly intruded water mass for several seeks to determine rates and magnitudes of phyto- and zooplankton for development.

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

    Science.gov (United States)

    Hauss, H.; Christiansen, S.; Schütte, F.; Kiko, R.; Edvam Lima, M.; Rodrigues, E.; Karstensen, J.; Löscher, C. R.; Körtzinger, A.; Fiedler, B.

    2015-11-01

    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 thought to decline in the course of climate change. The recent discovery of mesoscale eddies that harbour a shallow suboxic (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. A marked reduction in acoustic target strength (derived from shipboard ADCP, 75kHz) within the shallow OMZ at nighttime was evident. Acoustic scatterers were avoiding the depth range between about 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 have been identified followed by zooplankton in response to the eddy OMZ: (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, Oncaea spp., eucalanoid copepods), (iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes), and iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey-predator encounter rates, rendering

  7. 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,...

  8. 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...

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

    Data.gov (United States)

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

  10. Crustacean zooplankton species richness in Chilean lakes and ponds (23°-51°S

    Directory of Open Access Journals (Sweden)

    Patricio De los Ríos-Escalante

    2013-07-01

    Full Text Available Chilean inland-water ecosystems are characterized by their low species-level biodiversity. This study analyses available data on surface area, maximum depth, conductivity, chlorophyll-α concentration, and zooplankton crustacean species number in lakes and ponds between 23° and 51°S. The study uses multiple regression analysis to identify the potential factors affecting the species number. The partial correlation analysis indicated a direct significant correlation between chlorophyll-α concentration and species number, whereas the multiple regression analysis indicated a direct significant response of species number to latitude and chlorophyll-α concentration. These results agree with findings from comparable ecosystems in Argentina and New Zealand.

  11. Interactions between piscivores, zooplanktivores and zooplankton in submerged macrophytes : Preliminary observations from enclosure and pond experiments

    DEFF Research Database (Denmark)

    Jacobsen, Lene; Perrow, M.R.; Landkildehus, F.;

    1997-01-01

    and the presence of zooplanktivores typically changed the habitat selection of cladoceran zooplankton. In the case of piscivore/zooplanktivore interactions, the risk of predation was enough to generate clear responses even where the losses to predation were low. However, only in the enclosure experiment...... suggest that this mechanism is plausible with the set of piscivores (pike Esox lucius and perch Perca fluviatilis) and the zooplanktivores (0+ roach Rutilus rutilus and perch) common in temperate Europe. The presence of piscivores typically changed the habitat use and the activity level of zooplanktivores...... of foraging within structured habitats) of the predator (both piscivore and zooplanktivore), absolute and relative densities of predator and prey and predator dietary choice....

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

    Science.gov (United States)

    Bunnell, D.B.; Davis, B.M.; 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

  13. Developing a Pilot Maritime Spatial Plan for the Pomeranian Bight and Arkona Basin

    DEFF Research Database (Denmark)

    Käppeler, Bettina; Toben, Susan; Chmura, Grazyna;

    2012-01-01

    in the Pomeranian Bight/Arkona Basin. The draft spatial plan is the result of a planning exercise which took place outside the formal planning processes as legally binding agreements already exist for the German EEZ and the territorial waters of Mecklenburg-­‐Vorpommern. Working with diverse stakeholders in Poland...... for each of the uses identified in the stocktake. For shipping for example, a key objective is to promote safe and clean shipping and port development and reduce the collision risk in dangerous goods transport. For energy, a key objective is to find suitable areas for offshore wind farms. Objectives were......, staff time, hardware, software, regular meetings, data accessibility and compatibility etc)....

  14. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    Energy Technology Data Exchange (ETDEWEB)

    Dorneles, Paulo Renato [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: dorneles@biof.ufrj.br; Lailson-Brito, Jose [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: lailson@uerj.br; Aguiar dos Santos, Roberta [Centro de Pesquisa e Gestao de Recursos Pesqueiros do Litoral Sudeste e Sul, IBAMA, 88301-700 Itajai, SC (Brazil)]. E-mail: gibteuthis@yahoo.com.br; Silva da Costa, Paulo Alberto [Laboratorio de Dinamica de Populacoes Marinhas, UNIRIO, 22290-240 Rio de Janeiro, RJ (Brazil)]. E-mail: pauloascosta@uol.com.br; Malm, Olaf [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: olaf@biof.ufrj.br; Azevedo, Alexandre Freitas [Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: azevedo.alex@uol.com.br; Machado Torres, Joao Paulo [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: jptorres@biof.ufrj.br

    2007-07-15

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in {mu}g/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 {mu}g/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods.

  15. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    International Nuclear Information System (INIS)

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in μg/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 μg/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods

  16. Brazilian sardine (Sardinella brasiliensis spawning in the southeast Brazilian Bight over the period 1976-1993

    Directory of Open Access Journals (Sweden)

    Yasunobu Matsuura

    1998-01-01

    Full Text Available Based on sampling over the period 1976-1993 in the southeast Brazilian Bight, the distribution of spawning of the Brazilian sardine (Sardinella brasi/iensis is described in relation to environmental conditions. The area of intense spawning occurs in the southern part of the bight where coastal upwelling was less /Tequent. Spawning intensity showed high interannllal variation and the egg abundance in the survey area ranged /Tom 99 billion eggs in the January 1988 cruise to 4669 billion eggs in the January 1981 cruise. Peak spawning takes place one hour after midnight and eggs hatch . out within 19 hours with a water temperature of 24 °e.Baseado nos dados coletados durante nove cruzeiros oceanográficos realizados na região sudeste, as áreas de desova da sardinha-verdadeira (Sardinella brasiliensis foram apresentadas c discutidas em relação às condições oceanográficas. As áreas de desova intensiva foram localizadas na parte sul da área de investigação, onde a ressurgência costeira foi menos freqüente. A intensidade de desova demonstrou uma variação anual relativamente grande. A produção total de ovos da sardinha- ­verdadeira variou de 99 bilhões de ovos durante o cruzeiro de janeiro de 1988 para 4669 bilhões de ovos em janeiro de 1981. O pico de desova ocorre na camada de mistura de superfície uma hora após a meia noite e os ovos eclodem em 19 horas com a temperatura de água 24 °e.

  17. Zooplankton data collected from NERPA in Arctic Ocean; 11 August 1936 to 06 October 1936 (NODC Accession 9800135)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Arctic Ocean from NERPA. Data were collected from 11 August 1936 to 06 October 1936 by Arctic and...

  18. Zooplankton data collected from THOMAS G. THOMPSON in Bering Sea; 01 April 1980 to 13 October 1981 (NODC Accession 9800133)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Bering Sea from THOMAS G. THOMPSON. Data were collected from 01 April 1980 to 13 October 1981 by...

  19. Zooplankton data collected from THOMAS G. THOMPSON in Arabian Sea; 19 August 1995 to 22 December 1995 (NODC Accession 9800200)

    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 19 August 1995 to 22 December 1995 by...

  20. Zooplankton data collected from THOMAS G. THOMPSON in Arabian Sea; 18 September 1994 to 27 December 1995 (NODC Accession 9800077)

    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 18 September 1994 to 27 December 1995...

  1. ZOOPLANKTON DIVERSITY AND ITS RELATIONSHIP WITH PHYSICO-CHEMICAL PARAMETERS IN MANI RESERVOIR OF WESTERN GHATS, INDIA

    OpenAIRE

    D. N. Veerendra; S. Thirumala; H. Manjunatha; H. B. Aravinda

    2012-01-01

    Studies on relationship between zooplankton abundance and water quality parameter in Mani reservoir were made between January 2008 and December 2008.in the urrent 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.

  2. Variability of spatial and temporal distribution of zooplankton communities at Matrouh beaches, south-eastern Mediterranean Sea, Egypt

    OpenAIRE

    Sawsan M. Aboul Ezz; Ahmed M.M. Heneash; Gharib, Samiha M.

    2014-01-01

    The objectives of this work are to determine the main environmental drivers of zooplankton variability in water of Matrouh beach, south-eastern Mediterranean Sea and to evaluate the differences in zooplankton abundance and population structure in relation to chemical and biological parameters. Samples were collected seasonally from summer 2009 to summer 2010 at 10 sampling beaches. The zooplankton community was characterized by its high variability, and lower diversity. Zooplankton variabilit...

  3. PHYTOPLANKTON AND ZOOPLANKTON SEASONAL DYNAMICS IN A SUBTROPICAL ESTUARY: IMPORTANCE OF CYANOBACTERIA

    Science.gov (United States)

    Murrell, Michael C. and Emile M. Lores. 2004. Phytoplankton and Zooplankton Seasonal Dynamics in a Subtropical Estuary: Importance of Cyanobacteria. J. Plankton Res. 26(3):371-382. (ERL,GB 1190). A seasonal study of phytoplankton and zooplankton was conducted from 1999-20...

  4. Cyanobacteria as a carbon source for zooplankton in eutrophic Lake Taihu, China, measured by

    NARCIS (Netherlands)

    de Kluijver, A.; Yu, J.L.; Houtekamer, M.; Middelburg, J.J.; Liu, Z.W.

    2012-01-01

    Using a combined stable-isotope and fatty-acid approach, we examined carbon-transfer routes from the cyanobacterium Microcystis to zooplankton in eutrophic Lake Taihu, China. Microcystis is generally considered poor food for zooplankton, and we hypothesized that most Microcystis carbon flows to zoop

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

    NARCIS (Netherlands)

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

    1996-01-01

    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 selec

  6. Effect of Main-stem Dams on Zooplankton Communities of the Missouri River (USA)

    Science.gov (United States)

    We examined the distribution and abundance of zooplankton from 146 sites on the Missouri River and found large shifts in the dominance of major taxa between management zones of this regulated river. Crustacean zooplankton were dominant in the inter-reservoir zone of the river, an...

  7. Assessment of Zooplankton Size Fractionation for Monitoring Fry and Fingerling Culture Ponds

    Science.gov (United States)

    Methodology was formulated for use in the rapid assessment of zooplankton in channel catfish ponds. Understanding zooplankton prey size is useful for effective pond management. Size fractionation using differential sieve sizes was an effective means of separating size classes in live material, whe...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Srivastava, Y.

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

  9. 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

    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...

  10. Cladoceran zooplankton abundance under clear and snow-covered ice

    Science.gov (United States)

    DeBates, T.J.; Chipps, S.R.; Ward, M.C.; Werlin, K.B.; Lorenzen, P.B.

    2003-01-01

    We described the distribution of cladoceran zooplankton under the ice in a natural, glacial lake. Local light availability apparently altered the spatial distribution of cladocerans. Light levels measured under snow-covered areas (0.178 lux) were an order of magnitude less than those measured at the same depth under clear ice (1.750 lux). Cladoceran density under snow-covered areas was significantly higher (Bosmina spp.=3.34/L; Daphnia spp.=0.61/L) than cladoceran abundance under clear ice (Bosmina spp.=0.91/L; Daphnia spp.=0.19/L).

  11. Fatty acid transformation in zooplankton: from seston to benthos

    DEFF Research Database (Denmark)

    Tiselius, Peter; Hansen, Benni Winding; Calliari, Danilo

    2012-01-01

    activity. To test this hypothesis, we sampled seston, zooplankton and sediment trap material for FA analysis during 5 campaigns spanning 4 seasons at a coastal site on the west coast of Sweden. Saturated (SAFAs) and monounsaturated (MUFAs) FAs dominated seston and trap material, while copepods contained 75...... to 90% polyunsaturated FAs (PUFAs). Sedimentation of bulk particulate organic carbon did not vary significantly with season (coefficient of variation, CV = 33%), while pigment (CV = 49%) and in particular faecal pellet fluxes (CV = 100%) were highly variable as a result of copepod feeding activity...

  12. Zooplankton data collected from zooplankton net casts from TOWNSEND CROMWELL in TOGA Area of Pacific Ocean; 09 February 1984 to 04 March 1992 (NODC Accession 9800046)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were taken on five cruises from 1984 through 1992 at Johnston Island, Hancock Seamounts, and Palmyra Island, the latter of which was concentrated...

  13. 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...

  14. 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

    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...

  15. Daily variation of zooplankton abundance and evenness in the Rosana reservoir, Brazil: biotic and abiotic inferences

    Directory of Open Access Journals (Sweden)

    Érica M. Takahashi

    2014-03-01

    Full Text Available The zooplankton community presents stochastic temporal fluctuation and heterogeneous spatial variation determined by the relationships among the organisms and environmental conditions. We predicted that the temporal and spatial zooplankton distribution is heterogeneous and discrete, respectively, and that the daily variation of most abundant species is related to environmental conditions, specifically the availability of resources. Zooplankton samples were collected daily at three sampling stations in a lateral arm of the Rosana Reservoir (SP/PR. The zooplankton did not present significant differences in abundance and evenness among sampling stations, but the temporal variation of these attributes was significant. Abiotic variables and algal resource availability have significantly explained the daily variation of the most abundant species (p<0.001, however, the species distribution makes inferences on biotic relationships between them. Thus, not only the food resource availability is influential on the abundance of principal zooplankton species, but rather a set of factors (abiotic variables and biotic relationships.

  16. 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.

  17. Zooplankton community analysis in the Changjiang River estuary by single-gene-targeted metagenomics

    Science.gov (United States)

    Cheng, Fangping; Wang, Minxiao; Li, Chaolun; Sun, Song

    2014-07-01

    DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similaritymetagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.

  18. Consistency and complementarity of different coastal ocean observations: A neural network-based analysis for the German Bight

    Science.gov (United States)

    Wahle, K.; Stanev, E. V.

    2011-05-01

    HF radar measurements in the German Bight and their consistency with other available observations were analyzed. First, an empirical orthogonal function (EOF) analysis of the radial component of the surface current measured by one radar was performed. Afterwards, Neural Networks (NNs) were trained to now- and forecast the first five EOFs from tide gauge measurements. The inverse problem, i.e., to forecast a sea level from these EOFs was also solved using NNs. For both problems, the influence of wind measurements on the nowcast/forecast accuracy was quantified. The forecast improves if HF radar data are used in combination with wind data. Analysis of the upscaling potential of HF radar measurements demonstrated that information from one radar station in the German Bight is representative of an area larger than the observational domain and could contribute to correcting information from biased observations or numerical models.

  19. 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 (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, Oncaea spp., eucalanoid copepods); (iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes); and (iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey-predator encounter rates, rendering zooplankton and micronekton more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 µmol O2 kg-1. This may result in a positive feedback on the OMZ oxygen consumption rates, since zooplankton and micronekton respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline.

  20. Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

    2012-04-01

    In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3-4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3-4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the

  1. Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

    2012-01-01

    In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3–4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3–4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the

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

    Science.gov (United States)

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

    2005-01-01

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

  3. Movement patterns, habitat preferences, and fisheries biology of the common thresher shark (Alopias vulpinus) in the Southern California Bight

    OpenAIRE

    Cartamil, Daniel Patrick

    2009-01-01

    The common thresher shark (Alopias vulpinus) is a pelagic species that constitutes the largest commercial shark fishery in California waters. Despite its commercial value, little is known of thresher shark biology, nor is there adequate data on which to base fishery management decisions. This dissertation entails four studies dealing with the biology and fisheries interactions of common thresher shark in the Southern California Bight (SCB). Chapter 1 examines the movement patterns of adult an...

  4. Interactive effects of temperature, ultraviolet radiation and food quality on zooplankton alkaline phosphatase activity.

    Science.gov (United States)

    Wolinski, Laura; Modenutti, Beatriz; Souza, Maria Sol; Balseiro, Esteban

    2016-06-01

    Ultraviolet Radiation (UVR) is a stressor for aquatic organisms affecting enzyme activities in planktonic populations because of the increase in reactive oxygen species. In addition, UVR exposure combined with other environmental factors (i.e. temperature and food quality) could have even higher detrimental effects. In this work, we aimed to determine the effect of UVR on somatic Alkaline Phosphatase Activity (APA) and Glutathione S-Transferase (GST) activity on the cladoceran Daphnia commutata under two different temperatures (10 °C and 20 °C) and under three food qualities (carbon:phosphorus ratios: 1150, 850 and 550). APA is a biomarker that is considered as a P deficiency indicator in zooplankton. Since recovery from UVR damage under dark conditions is an ATP depending reaction we also measured APA during recovery phases. We carried out a laboratory experiment combining different temperatures and food qualities with exposition to UVR followed by luminic and dark phases for recovery. In addition, we exposed organisms to H2O2, to establish if the response on APA to UVR was a consequence of the reactive oxygen species produced these short wavelengths. Our results showed that somatic APA was negatively affected by UVR exposure and this effect was enhanced under high temperature and low food quality. Consistently, GST activity was higher when exposed to UVR under both temperatures. The H2O2 experiments showed the same trend as UVR exposure, indicating that APA is affected mainly by oxidative stress than by direct effect of UVR on the enzyme. Finally, APA was affected in the dark phase of recovery confirming the P demands. These results enlighten the importance of food quality in the interacting effect of UVR and temperature, showing that C:P food ratio could determine the success or failure of zooplanktonic populations in a context of global change. PMID:26895537

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

    Science.gov (United States)

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

    2014-08-01

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

  6. Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency

    Science.gov (United States)

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

    2016-01-01

    Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous zooplankton is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton. PMID:27510848

  7. Zooplankton feeding on the nuisance flagellate Gonyostomum semen.

    Directory of Open Access Journals (Sweden)

    Karin S L Johansson

    Full Text Available The large bloom-forming flagellate Gonyostomum semen has been hypothesized to be inedible to naturally occurring zooplankton due to its large cell size and ejection of long slimy threads (trichocysts induced by physical stimulation. In a grazing experiment using radiolabelled algae and zooplankton collected from lakes with recurring blooms of G. semen and lakes that rarely experience blooms, we found that Eudiaptomus gracilis and Holopedium gibberum fed on G. semen at high rates, whereas Daphnia cristata and Ceriodaphnia spp. did not. Grazing rates of E. gracilis were similar between bloom-lakes and lakes with low biomass of G. semen, indicating that the ability to feed on G. semen was not a result of local adaptation. The high grazing rates of two of the taxa in our experiment imply that some of the nutrients and energy taken up by G. semen can be transferred directly to higher trophic levels, although the predominance of small cladocerans during blooms may limit the importance of G. semen as a food resource. Based on grazing rates and previous observations on abundances of E. gracilis and H. gibberum, we conclude that there is a potential for grazer control of G. semen and discuss why blooms of G. semen still occur.

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

    Science.gov (United States)

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

    1980-03-01

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

  9. The Role of Intense Storms on Backbarrier Morphodynamics: Examples From the New York/New Jersey Bight

    Science.gov (United States)

    Scileppi, E.; Donnelly, J. P.; Mahoney, M.

    2004-12-01

    Intense storms can significantly modify coastal landforms. Understanding the influence of these relatively rare, but potentially important, events on the evolution of coastal systems is important if we are to reliably forecast future changes. In the New York/New Jersey Bight the most intense storms are landfalling tropical cyclones that approach the region from the south. Since European settlement, four severe tropical cyclones, occurring in 1693, 1788, 1821, and 1893, have made landfall in the New York/New Jersey Bight. Each of these storms resulted in a rise in water level of over 2.5 meters above mean sea level (MSL) in New York City. Storm surges of this magnitude can overtop and breach barrier beaches creating inlets and depositing overwash deposits across the surface of backbarrier marshes. Severe winter storms, near miss, and minimal hurricanes impacting the region in the 20th century caused water levels to rise approximately 1.5-2 meters above MSL. Events of this magnitude likely caused erosion of the beach face, and limited overtopping and breaching restricted to areas with little or no dune development. Backbarrier sediments can preserve an archive of environmental changes. We collected a series of vibracores from four backbarrier marshes in the New York/New Jersey Bight. High-resolution grain-size and loss-on-ignition analyses were used to characterize the sediments and yield evidence of multiple storm-induced deposits. Heavy metal pollution horizons, pollen stratigraphic data, and C-14 ages were used to provide chronological control. In order to link the dynamics of the barriers with the sedimentary framework of the backbarrier estuary, we used ground-penetrating radar (GPR) to map the subsurface character of the barrier sediments. Our results indicate that intense tropical cyclones are very important in shaping the barrier and backbarrier environments in the New York/New Jersey Bight. Backbarrier and barrier sediments reveal records of overwash

  10. 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.

  11. Short-term variation in zooplankton community from Daya Bay with outbreaks of Penilia avirostris

    Directory of Open Access Journals (Sweden)

    Kaizhi Li

    2014-06-01

    Full Text Available The zooplankton community structure in bays fluctuates as a result of anthropogenic activities in such waters. We focused on the short-term variability of a zooplankton community and compared its differences at the outflow of a nuclear power plant (ONPP, in a marine cage-culture area (MCCA and in unpolluted waters (UW in the south-west part of Daya Bay from 28 April to 1 June 2001. Environmental factors and zooplankton abundance differed significantly among stations at ONPP, MCCA and UW: high temperatures and a high zooplankton abundance occurred at ONPP, while a high chlorophyll a concentration and a low zooplankton abundance prevailed in MCCA. Statistical analysis revealed that the zooplankton diversity and abundance could be reduced by the activity of the marine cage-culture in a short time. Penilia avirostris made up an important component of the zooplankton in the study area, its abundance ranging widely from 16 to 7267 indiv. m-3 from April to June and peaking at the ONPP outflow. The outbreak of P. avirostris probably resulted from the combined effects of favourable water temperature, food concentration and its parthenogenetic behaviour.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Development and validation of hydroacoustic monitoring concepts for the coastal German Bight (SE North Sea)

    Science.gov (United States)

    Mielck, Finn; Hass, H. Christian; Holler, Peter; Bartholomä, Alexander; Neumann, Andreas; Kröncke, Ingrid; Reimers, Hans-Christian; Capperucci, Ruggero

    2016-04-01

    The joint research project WIMO (Wissenschaftliche Monitoringkonzepte für die Deutsche Bucht/Scientific Monitoring Concepts for the German Bight, NE North Sea) aims at providing methods for detection and analysis of seabed habitats using modern remote sensing techniques. Our subproject focuses on hydroacoustic techniques in order to gain information about seafloor environments and sediment dynamics. In a timeframe of four years, several key areas in the German Bight were repeatedly observed using different hydroacoustic gear (i. e. sidescan sonars, single/multibeam echo sounders and sub-bottom profilers). In order to ground-truth the acoustic data, hundreds of grab samples and underwater videos were taken. With these techniques it is possible to distinguish between different seafloor habitats, which range from muddy to sandy seafloors (esp. near the barrier islands) to rugged or vegetated/populated reefs around Helgoland. The conducted monitoring program revealed seasonal changes regarding the abundance of the sand mason worm (Lanice conchilega) and the brittle star (Amphiora filiformis) as well as ongoing sedimentary processes driven by tidal currents and wind/storms. It was also possible to determine relationships between sediment characteristics and benthos in some key areas. An essential part of our project included a comparison between the datasets obtained with different hydroacoustic devices, configurations, and evaluation methods in the same study areas. The investigation reveals that there could be distinct differences in interpreting the data and hence in the determination of prevailing seafloor habitats, especially in very heterogeneous areas and at transition zones between the habitats. Therefore, it is recommended to employ more than one hydroacoustic system (preferably a singlebeam device combined with a wide-swath sonar system) synchronously during a survey in order to gain more reliable and detailed information about the seafloor environments. The

  14. Spatial and temporal patterns in oxygen and nutrient fluxes in sediment of German Bight (North Sea)

    Science.gov (United States)

    Neumann, Andreas; Friedrich, Jana; van Beusekom, Justus; Naderipour, Céline

    2016-04-01

    The German Bight in the southern North Sea is affected by intensive anthropogenic exploitation. Over a century of intensive use by shipping, fishery, and input by polluted rivers has pushed the coastal ecosystem far from its pristine state. The nutrient load reached a maximum in the early 1990s (Amann et al. 2012), and implementation of environmental protection policies substantially decreased the riverine nutrient load. While the riverine input of pollutants has constantly reduced since then, new forms of sea exploitation emerge. The most noticeable example is the installation of more than 600 wind turbines over the past few years in the German EEZ, and additionally 1,200 are already planned. The impact of these installations on hydrology and biogeochemical cycles is largely unclear. In a series of monitoring cruises we repeatedly sampled the sediment at a set of monitoring stations, which represent all typical habitats of the German Bight. We deployed benthic landers for in-situ chamber incubations and performed ex-situ whole-core incubations to investigate the benthic fluxes of oxygen and nutrients, and their spatial and temporal variability. Our first results indicate that benthic nutrient recycling is more intense during summer than during winter, which suggests that biological processes contribute substantially to the recycling of nutrients. The fluxes of reactive nitrogen appear lower than observations from 1992 (Lohse et al. 1993), when riverine N loads were at their maximum (Amann et al. 2012). The comparison of our recent measurements with observations from the past decades will enable us to assess the effect of decreasing nutrient discharge into the coastal North Sea. Our results will further set a baseline for elucidating the impact of the massive installation of wind turbines in the near future. This study contributes to the NOAH project (North Sea; Observation and Assessment of Habitats). References Amann T., A. Weiss, and J. Hartmann (2012): Carbon

  15. High Resolution Quaternary Seismic Stratigraphy of the New York Bight Continental Shelf

    Science.gov (United States)

    Schwab, William C.; Denny, J.F.; Foster, D.S.; Lotto, L.L.; Allison, M.A.; Uchupi, E.; Swift, B.A.; Danforth, W.W.; Thieler, E.R.; Butman, Bradford

    2003-01-01

    A principal focus for the U.S. Geological Survey (USGS) Coastal and Marine Geology Program (marine.usgs.gov) is regional reconnaissance mapping of inner-continental shelf areas, with initial emphasis on heavily used areas of the sea floor near major population centers. The objectives are to develop a detailed regional synthesis of the sea-floor geology in order to provide information for a wide range of management decisions and to form a basis for further investigations of marine geological processes. In 1995, the USGS, in cooperation with the U.S. Army Corps of Engineers (USACOE), New York District, began to generate reconnaissance maps of the continental shelf seaward of the New York - New Jersey metropolitan area. This mapping encompassed the New York Bight inner-continental shelf, one of the most heavily trafficked and exploited coastal regions in the United States. Contiguous areas of the Hudson Shelf Valley, the largest physiographic feature on this segment of the continental shelf, also were mapped as part of a USGS study of contaminated sediments (Buchholtz ten Brink and others, 1994; 1996). The goal of the reconnaissance mapping was to provide a regional synthesis of the sea-floor geology in the New York Bight area, including: (a) a description of sea-floor morphology; (b) a map of sea-floor sedimentary lithotypes; (c) the geometry and structure of the Cretaceous strata and Quaternary deposits; and (d) the geologic history of the region. Pursuing the course of this mapping effort, we obtained sidescan-sonar images of 100 % of the sea floor in the study area. Initial interpretations of these sidescan data were presented by Schwab and others, (1997a, 1997b, 2000a). High-resolution seismic-reflection profiles collected along each sidescan-sonar line used multiple acoustic sources (e.g., watergun, CHIRP, Geopulse). Multibeam swath-bathymetry data also were obtained for a portion of the study area (Butman and others, 1998;). In this report, we present a series

  16. 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.

  17. Horizontal distribution of Fukushima-derived radiocesium in zooplankton in the northwestern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    M. Kitamura

    2013-04-01

    Full Text Available The magnitude of the 9.0 Tohoku earthquake and the ensuing tsunami on 11 March 2011, inflicted heavy damage on the Fukushima Dai-ichi nuclear power plant (FNPP1. Fission products were emitted, falling over a broad range in the northern hemisphere, and water contaminated with radionuclides leaked into the ocean. In this study, we described the horizontal distribution of the Fukushima-derived radiocesium in zooplankton and in seawater in the western North Pacific Ocean (500–2100 km from the FNPP1 10 months after the accident. 134Cs and 137Cs were detected in zooplankton and seawater from all the stations. Because of its short half-lives, 134Cs detected in our samples could only be derived from the FNPP1 accident. The highest 137Cs activity in zooplankton was same order of magnitude as that one month after the accident, and average activity was one or two orders of magnitude higher than 137Cs activities observed before the accident around Japan. Horizontally, the radiocesium activity concentrations in zooplankton were high at around 25° N while those in surface seawater were high at around the transition area between the Kuroshio and the Oyashio Currents (36–40° N. We observed subsurface radiocesium maxima in density range of the North Pacific Subtropical Mode Water and occurrence of many diel vertical migratory zooplanktons. These suggested that the high activity concentrations in the subtropical zooplankton at around 25° N were connected to the subsurface radiocesium and active vertical migration of zooplankton. However, the high activity concentrations of radiocesium in subsurface seawater did not necessarily follow the higher radiocesium activity in zooplankton. Biological characteristics of zooplankton community possibly influenced how large was contamination of radiocesium in the community but it is still unknown what kind of biological factors were important.

  18. Trophic ecology and vertical patterns of carbon and nitrogen stable isotopes in zooplankton from oxygen minimum zone regions

    Science.gov (United States)

    Williams, Rebecca L.; Wakeham, Stuart; McKinney, Rick; Wishner, Karen F.

    2014-08-01

    The unique physical and biogeochemical characteristics of oxygen minimum zones (OMZs) influence plankton ecology, including zooplankton trophic webs. Using carbon and nitrogen stable isotopes, this study examined zooplankton trophic webs in the Eastern Tropical North Pacific (ETNP) OMZ. δ13C values were used to indicate zooplankton food sources, and δ15N values were used to indicate zooplankton trophic position and nitrogen cycle pathways. Vertically stratified MOCNESS net tows collected zooplankton from 0 to 1000 m at two stations along a north-south transect in the ETNP during 2007 and 2008, the Tehuantepec Bowl and the Costa Rica Dome. Zooplankton samples were separated into four size fractions for stable isotope analyses. Particulate organic matter (POM), assumed to represent a primary food source for zooplankton, was collected with McLane large volume in situ pumps. The isotopic composition and trophic ecology of the ETNP zooplankton community had distinct spatial and vertical patterns influenced by OMZ structure. The most pronounced vertical isotope gradients occurred near the upper and lower OMZ oxyclines. Material with lower δ13C values was apparently produced in the upper oxycline, possibly by chemoautotrophic microbes, and was subsequently consumed by zooplankton. Between-station differences in δ15N values suggested that different nitrogen cycle processes were dominant at the two locations, which influenced the isotopic characteristics of the zooplankton community. A strong depth gradient in zooplankton δ15N values in the lower oxycline suggested an increase in trophic cycling just below the core of the OMZ. Shallow POM (0-110 m) was likely the most important food source for mixed layer, upper oxycline, and OMZ core zooplankton, while deep POM was an important food source for most lower oxycline zooplankton (except for samples dominated by the seasonally migrating copepod Eucalanus inermis). There was no consistent isotopic progression among the four

  19. Assessment of concentration, bioaccumulation and sources of polycyclic aromatic hydrocarbons in zooplankton of Chabahar Bay.

    Science.gov (United States)

    Ziyaadini, Morteza; Mehdinia, Ali; Khaleghi, Leila; Nassiri, Mahmoud

    2016-06-15

    The amounts and sources of polycyclic aromatic hydrocarbons (PAHs) and their bioaccumulation factors (BAFs) in the zooplankton community of Chabahar Bay were investigated. The highest amounts of total PAHs (tPAHs) in the water and zooplankton samples were 62.2ngL(-1) and 1478.6ngg(-1) dry weights, in near the Shahid Beheshti Port and desalination, respectively. The greatest amount of BAF (51,780) was obtained in the entry of Bay, and it was related to the phenanthrene accumulation. Using molecular ratio, the results showed that the major input source of PAH compounds in zooplankton of Chabahar Bay was pyrolytic (fuel) source. PMID:26944700

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

    Directory of Open Access Journals (Sweden)

    Ana María Gagneten

    2002-09-01

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

  1. Dynamical Complexity of a Spatial Phytoplankton-Zooplankton Model with an Alternative Prey and Refuge Effect

    Directory of Open Access Journals (Sweden)

    Weiwei Zhang

    2013-01-01

    Full Text Available The spatiotemporal dynamics of a phytoplankton-zooplankton model with an alternative prey and refuge effect is investigated mathematically and numerically. The stability of the equilibrium point and the traveling wave solution of the phytoplankton-zooplankton model are described based on theoretical mathematical work, which provides the basis of the numerical simulation. The numerical analysis shows that refuges have a strong effect on the spatiotemporal dynamics of the model according to the pattern formation. These results may help us to understand prey-predator interactions in water ecosystems. They are also relevant to research into phytoplankton-zooplankton ecosystems.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  3. Effects of zooplankton herbivory on biomarker proxy records

    Science.gov (United States)

    Grice, Kliti; Klein Breteler, Wim C. M.; Schouten, Stefan; Grossi, Vincent; de Leeuw, Jan W.; Sinninghe Damsté, Jaap S.

    1998-12-01

    The stable carbon isotopic compositions of cholesterol, generally the most dominant sterol in the copepod Temora, bears the δ13C "signature" of its dietary precursor sterol when fed on Isochrysis galbana and Rhodomonas sp. The δ13C of cholesterol in the faecal pellets released from Temora longicornis fed on Rhodomonas sp. is identical to the δ13C of the sterols in the diet, indicating that no significant carbon isotopic fractionation effects occur when the copepod modifies eukaryotic precursor sterols to cholesterol. Furthermore, the ratio of long-chain alkenones and their stable carbon isotopic compositions in I. galbana were identical to those egested in faecal material. Thus Zooplankton herbivory does not invalidate the use of these alkenones as a proxy for sea surface temperature and pCO2.

  4. RNA-Based Assessment of Diversity and Composition of Active Archaeal Communities in the German Bight

    Directory of Open Access Journals (Sweden)

    Bernd Wemheuer

    2012-01-01

    Full Text Available Archaea play an important role in various biogeochemical cycles. They are known extremophiles inhabiting environments such as thermal springs or hydrothermal vents. Recent studies have revealed a significant abundance of Archaea in moderate environments, for example, temperate sea water. Nevertheless, the composition and ecosystem function of these marine archaeal communities is largely unknown. To assess diversity and composition of active archaeal communities in the German Bight, seven marine water samples were taken and studied by RNA-based analysis of ribosomal 16S rRNA. For this purpose, total RNA was extracted from the samples and converted to cDNA. Archaeal community structures were investigated by pyrosequencing-based analysis of 16S rRNA amplicons generated from cDNA. To our knowledge, this is the first study combining next-generation sequencing and metatranscriptomics to study archaeal communities in marine habitats. The pyrosequencing-derived dataset comprised 62,045 archaeal 16S rRNA sequences. We identified Halobacteria as the predominant archaeal group across all samples with increased abundance in algal blooms. Thermoplasmatales (Euryarchaeota and the Marine Group I (Thaumarchaeota were identified in minor abundances. It is indicated that archaeal community patterns were influenced by environmental conditions.

  5. On analysing sea level rise in the German Bight since 1844

    Directory of Open Access Journals (Sweden)

    T. Wahl

    2010-02-01

    Full Text Available In this paper, a methodology to analyse observed sea level rise (SLR in the German Bight, the shallow south-eastern part of the North Sea, is presented. The paper focuses on the description of the methods used to generate and analyse mean sea level (MSL time series. Parametric fitting approaches as well as non-parametric data adaptive filters, such as Singular System Analysis (SSA are applied. For padding non-stationary sea level time series, an advanced approach named Monte-Carlo autoregressive padding (MCAP is introduced. This approach allows the specification of uncertainties of the behaviour of smoothed time series near the boundaries. As an example, the paper includes the results from analysing the sea level records of the Cuxhaven tide gauge and the Heligoland tide gauge, both located in the south-eastern North Sea. For comparison, the results from analysing a worldwide sea level reconstruction are also presented. The results for the North Sea point to a weak negative acceleration of SLR since 1844 with a strong positive acceleration at the end of the 19th century, to a period of almost no SLR around the 1970s with subsequent positive acceleration and to high recent rates.

  6. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    Science.gov (United States)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  7. Invertebrate communities associated with hard bottom habitats in the South Atlantic Bight

    Science.gov (United States)

    Wenner, E. L.; Knott, D. M.; Van Dolah, R. F.; Burrell, V. G.

    1983-08-01

    Epibenthic invertebrates associated with nine hard bottom areas in the South Atlantic Bight between South Carolina and northern Florida were collected with dredge, trawl, suction and grab samplers to evaluate species composition, biomass, abundance, diversity, spatial distributions, and seasonality (winter and summer). Species composition changed noticeably with depth and season. Inner and outer shelf stations were least similar in species composition. Middle shelf areas were transitional and contained taxa characteristic of both inner and outer sites. Bryozoa (88 taxa), Cnidaria (85 taxa), Porifera (67 taxa), Annelida (261 taxa) and Mollusca (203 taxa) represented the richest taxonomic groups of the 1175 taxa collected. Both diversity (1175 total taxa) and biomass (1995 kg total) of invertebrates from hard bottom areas exceeded those reported in the literature for sand bottom communities. Sponges accounted for >60% of the total invertebrate biomass collected by dredge and trawl during both seasons. High diversity values were attributed primarily to habitat complexity and did not exhibit any discernible pattern with depth or latitude.

  8. Newly Digitized Historical Climate Data of the German Bight and the Southern Baltic Sea Coasts

    Science.gov (United States)

    Röhrbein, Dörte; Tinz, Birger; von Storch, Hans

    2015-04-01

    The detection of historical climate information plays an important role with regard to the discussion on climate change, particularly on storminess. The German Meteorological Service houses huge archives of historical handwritten journals of weather observations. A considerable number of original observation sheets from stations along the coast of the German Bight and the southern Baltic Sea exists which has been until recently almost unnoticed. These stations are called signal stations and are positioned close to the shore. However, for this region meteorological observation data of 128 stations exist from 1877 to 1999 and are partly digitized. In this study we show an analysis of firstly newly digitized wind and surface air pressure data of 15 stations from 1877 to 1939 and we also present a case study of the storm surge at the coast of the southern Baltic Sea in December 1913. The data are quality controlled by formal, climatological, temporal and consistency checks. It is shown that these historical climate data are usable in consistency and quality for further investigations on climate change, e.g. as input for regional and global reanalysis.

  9. 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 repr

  10. 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...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  12. 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...

  13. 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.

    Seasonal variability in the physico-chemical features, zooplankton standing stock (biomass) and faunal composition in the Mandovi-Zuari estuarine system of Goa, India, during January to December 1990 were studied. Hydrobiological characteristics...

  14. Microdistribution of zooplankton in the neustonic realm of the eastern Arabian Sea during southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

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

    During the southwest monsoon season of 1987, the zooplankton distributions in the neustonic realm (upper 50 cm) of the eastern Arabian Sea were studied and compared with those in the water column. The upper microlayer (upper 15 cm) had generally...

  15. 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,...

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

    Data.gov (United States)

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

  17. Studies on the associates and parasites of zooplankton from southwest and southeast coasts of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    Associates and parasites of zooplankton from southwest and southeast coasts of India were studied. Among the epizoic forms two species of ciliates infesting copepods were new records from Indian waters. Eight species of suctorians were found epizoic...

  18. Size-differential feeding in Pinna nobilis L. (Mollusca: Bivalvia): Exploitation of detritus, phytoplankton and zooplankton

    Science.gov (United States)

    Davenport, John; Ezgeta-Balić, Daria; Peharda, Melita; Skejić, Sanda; Ninčević-Gladan, Živana; Matijević, Slavica

    2011-04-01

    The endangered fan shell Pinna nobilis is a large bivalve mollusc (animals has implications for future trophic studies of this endangered species. This study also provides the first demonstration of predation on zooplankton by P. nobilis.

  19. 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...

  20. Diel vertical migration of zooplankton at the S1 biogeochemical mooring revealed from acoustic backscattering strength

    Science.gov (United States)

    Inoue, Ryuichiro; Kitamura, Minoru; Fujiki, Tetsuichi

    2016-02-01

    We examined the diel vertical migration of zooplankton by using the backscatter strength obtained from moored acoustic Doppler current profilers at mooring site S1 in the North Pacific subtropical gyre. There was seasonal variability in the vertical distribution and migration of the high-backscatter layers in that they became deeper than the euphotic zone (seasons. Seasonal changes in daylight hours also affected the timing of the diel migration. We found that lunar cycles affected vertical distributions of zooplankton near the surface by changing the light intensity. Physical events, such as mixed-layer deepening and restratification and the passage of a mesoscale eddy, also affected zooplankton behavior possibly by changing food environment in the euphotic zone. Since the comparison with net samples indicated that the backscatter likely represents the bulk biomass, the accuracy of biomass estimates based on net samples could be influenced by the high temporal variability of zooplankton distributions.

  1. 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...

  2. The past and the future of zooplankton diversity studies in China seas

    OpenAIRE

    Zhaoli Xu

    2011-01-01

    China has among the largest latitudinal ranges of any country on Earth. Environmental factors such as diverse climate, hydrology and topography jointly determine levels of marine environmental diversityand therefore patterns in zooplankton diversity in China seas. Studies of zooplankton diversity in China progressed through different stages from a main focus on species taxonomy, diversity of distribution pattern, to a focus on environment influences on the ecological group, and finally a focu...

  3. Zooplankton diversity and abundance of mangrove ecosystem of Kali estuary, Karwar, west coast of India

    OpenAIRE

    Kumar, V; S.V. Roopa; B.K. Gangadhar

    2013-01-01

    The present study conducted at the mangrove ecosystem of Kali estuary. Samples were collected from the three fixed stations for the period of thirteen months from January 2008 to January 2009 at regular monthly interval to identify and quantify the abundance, taxonomy and relative ratio of phytoplankton and zooplankton. In the present study of species diversity of zooplankton groups in the mangrove area, composed of twelve groups comprising fifty two species major share comes from the copepod...

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

    Science.gov (United States)

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

    2013-01-01

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

  5. Tidal and diel influence on zooplankton occurrence in the Mandovi estuary, Goa

    OpenAIRE

    Selvakumar, R.A.; Goswami, S.C.; Goswami, U.

    1986-01-01

    Distribution and abundance of zooplankton over the tidal cycle were studied in the Mandovi estuary, Goa, during August and December 1971 and May 1972. Tide induced salinity fluctuations were obvious with high values during spring tides. Salinity was low during August, apparently due to precipitation and land run off but increased subsequently. The mean biomass values for the day and night collections were 13.6 and 19.8 ml/100 m super(3) respectively. Occurrence of most of the zooplankton taxa...

  6. The Impact of Fish Predation and Cyanobacteria on Zooplankton Size Structure in 96 Subtropical Lakes

    OpenAIRE

    Jing Zhang; Ping Xie; Min Tao; Longgen Guo; Jun De Chen; Li Li; Xuezhen Zhang; Lu Zhang

    2013-01-01

    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 zooplan...

  7. Linking light and productivity in lakes to zooplankton biodiversity, biomass and resource use efficiency

    OpenAIRE

    2013-01-01

    Introduction: Lake productivity is determined by the amount of nutrients and light available. While phosphorus is the main limiting nutrient in freshwater systems light availability can be reduced by several factors, while the most important one in Scandinavian lakes is the amount of dissolved organic compounds (DOC). Primary productivity can affect zooplankton biomass and diversity by bottom-up driven mechanisms while zooplankton biomass and diversity can also be affected by fish via top-dow...

  8. Influence Of Wastewater On Zooplankton Community Of The Daugava River After Daugavpils Wastewater Treatment Plant Modernization

    OpenAIRE

    Deksne, Rasma

    2015-01-01

    During seasonal studies 2010 (May-October, once/ thrice a month), samples of zooplankton were collected at the Daugava River section from 10 km upstream to 10 km downstream from the Daugavpils treatment plant wastewater discharge into the Daugava River. Changes in the quantitative and qualitative characteristics, saprobity index and species diversity (Shannon-Wiener index) were employed for the analysis of zooplankton community structure in the Daugava River. The Daugava River is polluted by ...

  9. Effect of salinity and fish predation on zooplankton dynamics in Hooghly-Matla estuarine system, India

    OpenAIRE

    Roy, Ujjwal; Sarwardi, S.; N. C. Majee; Ray, Santanu

    2016-01-01

    The Hooghly-Matla estuarine complex is the unique estuarine system of the world. Nutrient from the litterfall enrich the adjacent estuary through tidal influence which in turn regulate the phytoplankton, zooplankton and fish population dynamics. Environmental factors regulate the biotic components of the system, among which salinity plays a leading role in the regulation of phytoplankton, zooplankton and fish dynamics of the estuary. In this article, a $PZF$ model is considered with Holling t...

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

    OpenAIRE

    Cisewski, Boris; Strass, Volker

    2016-01-01

    The success of any efforts to determine the effects of climate change on marine ecosystems depends on understanding in the first instance the natural variations, which contemporarily occur on the interannual and shorter time scales. Here we present results on the environmental controls of zooplankton distribution patterns and behaviour in the eastern Weddell Sea, Southern Ocean. Zooplankton abundance and vertical migration are derived from the mean volume backscattering strength (MVBS) and th...

  11. Zooplankton biomass dynamics in oligotrophic versus eutrophic conditions : a test of the PEG model

    OpenAIRE

    Straile, Dietmar

    2015-01-01

    1. The model of the International Society of Limnology (SIL) Plankton Ecology working group (hereafter the PEG model) is a verbal model describing the patterns and driving factors of seasonal phytoplankton and zooplankton succession in oligotrophic and eutrophic lakes (Sommer et al., 1986). Despite being a citation classic, tests of the PEG model with respect to differences in zooplankton biomass dynamics between oligotrophic and eutrophic lakes are lacking.2. Here, I use the long-term data f...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    taxa (Bosmina coregoni maritima, Acartia spp., Pseudocalanus spp., Temora longicornis, Synchaeta spp.) contributed >10% to the zooplankton community composition. The appearance of cladocerans was mainly correlated with the phenology of thermocline development in the spring. The cladoceran B. coregoni...... maritima was a dominant member of this community during the warmest periods, preferring the surface waters above the thermocline. Copepods exhibited distinct, ontogenetic and seasonal changes in their distribution. The rotifers (Synchaeta sp.) were the most abundant zooplankton in May. Based...

  13. Vertical variability of trophic positions of zooplankton in the deep ocean.

    OpenAIRE

    Bode, A.; Mompeán-de-la-Rosa, M.C. (María del Carmen); Álvarez-Ossorio-Costa, M.T. (María Teresa); Fernández de Puelles, M.L.; Echevarría, F.; González-Gordillo, J.I.; Hernández-León, S.; Irigoien, X.; Acuña, J. L.

    2015-01-01

    presentation and abstract Zooplankton plays a key role in oceanic ecosystems. However, the trophic ecology of organisms in deep layers of the ocean is poorly known. In this study we analyze the variability of trophic positions of zooplankton collected across three ocean basins in the epi-, meso and bathypelagic domains. Stable carbon and nitrogen isotopes were used as indicators of the sources of nutrients and positions within the food web. The enrichment in heavy nitrogen isotopes with de...

  14. Kelimpahan dan Struktur Komunitas Zooplankton di Perairan Pulau Samalona, Kota Makassar, Provinsi Sulawesi Selatan

    OpenAIRE

    Rukminasari, Nita; Thana, Daud; Ilham B., Muhammad

    2012-01-01

    Penelitian ini bertujuan untuk mengetahui kelimpahan dan struktur komunitas zooplankton di perairan Pulau Samalona, Makassar. Hasil penelitian ini diharapkan dapat memberi gambaran tentang kondisi kestabilan komunitas zooplankton di perairan Pulau Samalona saat ini. Penelitian ini dilakukan pada bulan Juni sampai dengan Agustus 2008 di perairan Pulau Samalona, Makassar. Pengambilan sampel dilakukan sebanyak 4 kali dengan interval waktu 2 minggu, berdasarkan fase bulan terang dan bulan gelap. ...

  15. Variations of zooplankton in the frontal area of the Alboran sea (Mediterranean sea) in winter 1997

    OpenAIRE

    Youssara, F; Gaudy, R

    2001-01-01

    Zooplankton from the upper 200 m of the Almeria-Oran frontal region, (east of the Alboran sea, western Mediterranean) was sampled during winter 1997, using two nets equipped with 200 and 80 mum mesh. Eight sites representative of the different hydrodynamic structures (Mediterranean water, geostrophic Atlantic jet, associated anticyclonic gyre) were investigated over 2 d, using two day- and two night-samples per site. Zooplankton biomass was correlated to chlorophyll abundance, with lowest val...

  16. Seasonal Distribution of Zooplankton in Mahanadi Estuary (Odisha), East Coast of India: A Taxonomical Approach

    OpenAIRE

    C. R. Panda; S. Srichandan; N. C. Rout

    2013-01-01

    Study of coastal and estuarine water is important as they act as a medium of exchange of materials between land and ocean. Mahanadi estuarine system forms the largest system of its kind in Odisha. Zooplankton, the secondary producers plays a vital role in the hydrobiology and food chain regulation. The zooplankton diversity of Mahanadi estuary (Odisha) was investigated during postmonsoon (December 2009), premonsoon (April 2010) and monsoon (July 2010). Important hydrographical parameter...

  17. 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....

  18. Nonlinear Analysis in a Nutrient-Algae-Zooplankton System with Sinking of Algae

    OpenAIRE

    Chuanjun Dai; Min Zhao

    2014-01-01

    A reaction-diffusion-advection model is proposed for the Zeya Reservoir to study interactions between algae and zooplankton, including the diffusive spread of algae and zooplankton and the sinking of algae. The model is investigated both with and without sinking. Conditions of Hopf and Turing bifurcation in the spatial domain are obtained, and conditions for differential-flow instability that gives rise to the formation of spatial patterns are derived. Using numerical simulation, the authors ...

  19. Importance of light, temperature, zooplankton and fish in predicting the nighttime vertical distribution of Mysis diluviana

    Science.gov (United States)

    Boscarino, B.T.; Rusdtam, L.G.; Eillenberger, J.L.; O'Gorman, R.

    2009-01-01

    The opossum shrimp Mysis diluviana (formerly M. relicta) performs large amplitude diel vertical migrations in Lake Ontario and its nighttime distribution is influenced by temperature, light and the distribution of its predators and prey. At one location in southeastern Lake Ontario, we measured the vertical distribution of mysids, mysid predators (i.e. planktivorous fishes) and mysid prey (i.e. zooplankton), in addition to light and temperature, on 8 occasions from May to September, 2004 and 2005. We use these data to test 3 different predictive models of mysid habitat selection, based on: (1) laboratory-derived responses of mysids to different light and temperature gradients in the absence of predator or prey cues; (2) growth rate of mysids, as estimated with a mysid bioenergetics model, given known prey densities and temperatures at different depths in the water column; (3) ratio of growth rates (g) and mortality risk (??) associated with the distribution of predatory fishes. The model based on light and temperature preferences was a better predictor of mysid vertical distribution than the models based on growth rate and g:?? on all 8 occasions. Although mysid temperature and light preferences probably evolved as mechanisms to reduce predation while increasing foraging intake, the response to temperature and light alone predicts mysid vertical distribution across seasons in Lake Ontario. ?? Inter-Research 2009.

  20. Zooplankton assemblages in montane lakes and ponds of Mount Rainier National Park, Washington State, USA

    Science.gov (United States)

    Larson, G.L.; Hoffman, R.; McIntire, C.D.; Lienkaemper, G.; Samora, B.

    2009-01-01

    Water quality and zooplankton samples were collected during the ice-free periods between 1988 and 2005 from 103 oligotrophic montane lakes and ponds located in low forest to alpine vegetation zones in Mount Rainier National Park, Washington State, USA. Collectively, 45 rotifer and 44 crustacean taxa were identified. Most of the numerically dominant taxa appeared to have wide niche breadths. The average number of taxa per lake decreased with elevation and generally increased as maximum lake depths increased (especially for rotifers). With one exception, fish presence/absence did not explain the taxonomic compositions of crustacean zooplankton assemblages. Many rotifer species were common members of zooplankton assemblages in montane lakes and ponds in western North America, whereas the crustacean taxa were common to some areas of the west, but not others. Constraints of the environmental variables did not appear to provide strong gradients to separate the distributions of most zooplankton species. This suggests that interspecific competitive interactions and stochastic processes regulate the taxonomic structures of the zooplankton assemblages at the landscape level. Crustacean species that had broad niche breadths were associated with different rotifer taxa across the environmental gradients. Studies of zooplankton assemblages need to address both crustacean and rotifer taxa, not one or the other.

  1. Terrestrial carbon is a resource, but not a subsidy, for lake zooplankton

    Science.gov (United States)

    Kelly, Patrick T.; Solomon, Christopher T.; Weidel, Brian C.; Jones, Stuart E.

    2014-01-01

    Inputs of terrestrial organic carbon (t-OC) into lakes are often considered a resource subsidy for aquatic consumer production. Although there is evidence that terrestrial carbon can be incorporated into the tissues of aquatic consumers, its ability to enhance consumer production has been debated. Our research aims to evaluate the net effect of t-OC input on zooplankton. We used a survey of zooplankton production and resource use in ten lakes along a naturally occurring gradient of t-OC concentration to address these questions. Total and group-specific zooplankton production was negatively related to t-OC. Residual variation in zooplankton production that was not explained by t-OC was negatively related to terrestrial resource use (allochthony) by zooplankton. These results challenge the designation of terrestrial carbon as a resource subsidy; rather, the negative effect of reduced light penetration on the amount of suitable habitat and the low resource quality of t-OC appear to diminish zooplankton production. Our findings suggest that ongoing continental-scale increases in t-OC concentrations of lakes will likely have negative impacts on the productivity of aquatic food webs.

  2. Feeding and production of zooplankton in the Catalan Sea (NW Mediterranean)

    Science.gov (United States)

    Saiz, Enric; Calbet, Albert; Atienza, Dacha; Alcaraz, Miquel

    2007-08-01

    Zooplankton are key components of the structure and functioning of marine planktonic food webs. They are the main link of planktonic primary production towards top pelagic consumer levels (fish), and play a relevant role on the nutrient recycling in the water column and on the export of particulate matter out of the photic zone. In this paper, we review the present knowledge on the feeding and production of zooplankton in the Catalan Sea (NW Mediterranean), with special emphasis on copepods. Feeding of zooplankton in the Catalan Sea appears typically food limited, with average daily rations on a yearly basis in the order of 48% body C d -1. Heterotrophic prey constitute a relevant fraction of their diet, as an alternative to the scarce phytoplankton in the area. From a structural point of view, the trophic impact and control of their prey populations are low on standing stocks but, at certain times, zooplankton can exert a meaningful effect on their prey production. Regarding zooplankton production, the available estimates of growth rates in the area are based on the egg production rate of copepods. Egg production rates appear to be limited, especially in summer. Tentative estimates of copepod production in the area are in the order of 20-40 mg C m -2 d -1. In conclusion, this review confirms that the oligotrophic character of the NW Mediterranean constrains the feeding activity and production of zooplankton.

  3. FORMATION OF BACTERIAL AND ZOOPLANKTON COMPONENT OF NATURAL FOOD BASE UNDER EFFECT OF TRADITIONAL ORGANIC FERTILIZERS

    Directory of Open Access Journals (Sweden)

    S. Krazhan

    2013-12-01

    Full Text Available Purpose. Characterization of bacteria and zooplankton in rearing ponds using traditional fertilizers: cattle manure and bird droppings in modern conditions for fish farming. Methodology. Material collection and processing were carried out according to conventional hydrochemical and hydrobiological methods. Findings. We consider forming of bacteria and zooplankton component of natural food base of Irkliiv herbivorous fish nursery rearing ponds under the influenced of traditional organic fertilizers such as bird droppings (0,12 t/ha and cattle manure (2,0 t/ha. Each pond was planted by ongrowing Nyvka carp larvae (40,0 thousand ind./ha with silver carp (1,0 thousand ind./ha and grass carp larvae (1,0 thousand ind./ha. Qualitative and quantitative development of bacteria and zooplankton in fish-breeding ponds was investigated. The results show that in the development of the studied invertebrate groups of zooplankton in production ponds had no significant differences, except for rotifers, which group prevailed by the biomass to 3,6 times in the pond with the introduction of humus. Originality. The parameters of bacteria and zooplankton by the application of traditional organic fertilizers at present fish farming are studied. Practical value. These quantitative indicators of bacteria and zooplankton of fish-rearing ponds with water supply from Kremenchug reservoir, the application of cattle manure and bird droppings could be offered as an optimum data at present fish production stage.

  4. Analysis of the upscaling problem - A case study for the barotropic dynamics in the North Sea and the German Bight

    Science.gov (United States)

    Schulz-Stellenfleth, J.; Stanev, E. V.

    2016-04-01

    The upscaling problem is investigated using the barotropic dynamics of the North Sea and the German Bight as an example. The impact of small scale perturbations of bathymetry, bottom roughness, wind forcing, and boundary forcing is quantified using a two-dimensional linear barotropic model for the entire North Sea with 5 km resolution. The model is solved in the spectral domain for the dominant M2 tide. Comparisons with results from a fully nonlinear 3D circulation model show that the main circulation features are well captured by the spectral model. The impact of different types of perturbations is estimated by inversion of the model using the perturbation covariance matrix as input. Case studies with white noise and fully correlated noise are presented. It is shown that the German Bight area stands out in its sensitivity with respect to small scale uncertainties of bathymetry. Small scale changes of bottom roughness have a particularly strong effect in the English Channel. Small scale wind perturbations have a significant local effect only in very shallow near coastal areas. It is shown that uncorrelated noise introduced along an open boundary around the German Bight only has a very local effect. Perturbations with long correlation length are shown to lead to significant far field effects along the east coast of England. It is demonstrated that this effect is related to the boundary conditions used for the North Sea model. In a next step a German Bight grid with 1 km resolution is nested into the North Sea grid and the spectral model is solved in a two way nested configuration. It is shown that there are some significant local and far field effects caused by the change of resolution in this coastal area. Finally, the potential impact of observations taken in coastal areas is investigated by evaluating the Kalman a posteriori distribution of analysis vectors based on different assumptions about model errors. The area of influence of a single tide gauge is

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

    Directory of Open Access Journals (Sweden)

    Rubens M. Lopes

    2007-09-01

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

  6. Numerical diagnostic of the circulation in the Santos Bight with COROAS hydrographic data

    Directory of Open Access Journals (Sweden)

    Mauro Cirano

    1996-01-01

    Full Text Available This work represents part of the analyses of the data generated during the first two mesoscale hydrographic cruises of COROAS Project: one during the Summer and the other during the Winter of 1993. The area surveyed during these cruises is the region of the South Brazil Bight (or Santos Bight limited at the coast by the cities of Ubatuba and Iguape, extending from the 50 m isobath to oceanic regions with depths greater than 2500 m. The main goal of this work consisted of the adaptation of the Princeton Ocean Model to the area of study, including realistic topography, observed thermohaline structure and open boundaries. Using this model, a set of diagnostic experiments was realized using density structures based on the COROAS hydrographic data. The baroclinic velocity fields obtained, as expected from preliminary analyses of the thermohaline structures, showed similar features for the Brazil Current in bOla seasonal cruises. The results show an intrusion of Tropical Water over the continental shelf in the region between Ubatuba and Santos, both during the Summer and the Winter cruises. The results also suggest the penetration of the South Atlantic Central Water, underneath the Tropical Water, to the external part of the continental shelf in both occasions.Este artigo representa parte das análises desenvolvidas com os dados hidrográficos coletados durante os dois primeiros cruzeiros do sub-projeto Hidrografia de Meso-escala (HM do Projeto COROAS: o primeiro no verão e o outro no inverno de 1993. A área amostrada nos dois cruzeiros é limitada na costa pelas cidades de Iguape e Ubatuba, estendendo-se da isóbata de 50 m até regiões oceânicas com mais de 2500 m de profundidade. O objetivo central deste trabalho resumiu-se na adaptação do Princeton Ocean Model para a região de estudo, incluindo batimetria real, os campos termohalinos observados e contornos abertos. Usando-se esse modelo, realizou-se um conjunto de experimentos diagn

  7. Chemical composition and cycling of dissolved organic matter in the Mid-Atlantic Bight

    Science.gov (United States)

    Aluwihare, Lihini I.; Repeta, Daniel J.; Chen, Robert F.

    This study focuses on the chemical characterization of high molecular-weight dissolved organic matter (HMW DOM) isolated from the Middle Atlantic Bight in April 1994 and March 1996. Using proton nuclear magnetic resonance spectroscopy ( 1HNMR) and monosaccharide analysis we compared both spatial and temporal variations in the chemical structure of HMW DOM across this region. Our analyses support the presence of at least two compositionally distinct components to HMW DOM. The major component is acyl polysaccharide (APS), a biopolymer rich in carbohydrates, acetate and lipid, accounting for between 50% and 80% of the total high molecular-weight dissolved organic carbon (HMW DOC) in surface samples. APS is most abundant in fully marine, surface-water samples, and is a product of autochthonous production. Organic matter with spectral properties characteristic of humic substances is the second major component of HMW DOM. Humic substances are most abundant (up to 49% of the total carbon) in samples collected from estuaries, near the coast, and in deep water, suggesting both marine and perhaps terrestrial sources. Radiocarbon analyses of neutral monosaccharides released by the hydrolysis of APS have similar and modern (average 71‰) Δ 14C values. Radiocarbon data support our suggestion that these sugars occur as part of a common macromolecule, with an origin via recent biosynthesis. Preliminary radiocarbon data for total neutral monosaccharides isolated from APS at 300 and 750 m show this fraction to be substantially enriched relative to total HMW DOC and DOC. The relatively enriched radiocarbon values of APS at depth suggest APS is rapidly transported into the deep ocean.

  8. Identification of storm surge events over the German Bight from atmospheric reanalysis and climate model data

    Science.gov (United States)

    Befort, D. J.; Fischer, M.; Leckebusch, G. C.; Ulbrich, U.; Ganske, A.; Rosenhagen, G.; Heinrich, H.

    2015-06-01

    A new procedure for the identification of storm surge situations for the German Bight is developed and applied to reanalysis and global climate model data. This method is based on the empirical approach for estimating storm surge heights using information about wind speed and wind direction. Here, we hypothesize that storm surge events are caused by high wind speeds from north-westerly direction in combination with a large-scale wind storm event affecting the North Sea region. The method is calibrated for ERA-40 data, using the data from the storm surge atlas for Cuxhaven. It is shown that using information of both wind speed and direction as well as large-scale wind storm events improves the identification of storm surge events. To estimate possible future changes of potential storm surge events, we apply the new identification approach to an ensemble of three transient climate change simulations performed with the ECHAM5/MPIOM model under A1B greenhouse gas scenario forcing. We find an increase in the total number of potential storm surge events of about 12 % [(2001-2100)-(1901-2000)], mainly based on changes of moderate events. Yearly numbers of storm surge relevant events show high interannual and decadal variability and only one of three simulations shows a statistical significant increase in the yearly number of potential storm surge events between 1900 and 2100. However, no changes in the maximum intensity and duration of all potential events is determined. Extreme value statistic analysis confirms no frequency change of the most severe events.

  9. Identification of storm surge events over the German Bight from atmospheric reanalysis and climate model data

    Directory of Open Access Journals (Sweden)

    D. J. Befort

    2015-06-01

    Full Text Available A new procedure for the identification of storm surge situations for the German Bight is developed and applied to reanalysis and global climate model data. This method is based on the empirical approach for estimating storm surge heights using information about wind speed and wind direction. Here, we hypothesize that storm surge events are caused by high wind speeds from north-westerly direction in combination with a large-scale wind storm event affecting the North Sea region. The method is calibrated for ERA-40 data, using the data from the storm surge atlas for Cuxhaven. It is shown that using information of both wind speed and direction as well as large-scale wind storm events improves the identification of storm surge events. To estimate possible future changes of potential storm surge events, we apply the new identification approach to an ensemble of three transient climate change simulations performed with the ECHAM5/MPIOM model under A1B greenhouse gas scenario forcing. We find an increase in the total number of potential storm surge events of about 12 % [(2001–2100–(1901–2000], mainly based on changes of moderate events. Yearly numbers of storm surge relevant events show high interannual and decadal variability and only one of three simulations shows a statistical significant increase in the yearly number of potential storm surge events between 1900 and 2100. However, no changes in the maximum intensity and duration of all potential events is determined. Extreme value statistic analysis confirms no frequency change of the most severe events.

  10. Environmental context determines community sensitivity of freshwater zooplankton to a pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Stampfli, Nathalie C., E-mail: nathalie.stampfli@ufz.de [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau (Germany); Knillmann, Saskia; Liess, Matthias; Beketov, Mikhail A. [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)

    2011-07-15

    The environment is currently changing worldwide, and ecosystems are being exposed to multiple anthropogenic pressures. Understanding and consideration of such environmental conditions is required in ecological risk assessment of toxicants, but it remains basically limited. In the present study, we aimed to determine how and to what extent alterations in the abiotic and biotic environmental conditions can alter the sensitivity of a community to an insecticide, as well as its recovery after contamination. We conducted an outdoor microcosm experiment in which zooplankton communities were exposed to the insecticide esfenvalerate (0.03, 0.3, and 3 {mu}g/L) under different regimes of solar radiation and community density, which represented different levels of food availability and competition. We focused on the sensitivity of the entire community and analysed it using multivariate statistical methods, such as principal response curves and redundancy analysis. The results showed that community sensitivity varied markedly between the treatments. In the experimental series with the lowest availability of food and strongest competition significant effects of the insecticide were found at the concentration of 0.03 {mu}g/L. In contrast, in the series with relatively higher food availability and weak competition such effects were detected at 3 {mu}g/L only. However, we did not find significant differences in the community recovery rates between the experimental treatments. These findings indicate that environmental context is more important for ecotoxicological evaluation than assumed previously.

  11. Lagrangian model of zooplankton dispersion: numerical schemes comparisons and parameter sensitivity tests

    Institute of Scientific and Technical Information of China (English)

    QIU Zhongfeng; Andrea M. DOGLIOLI; HE Yijun; Francois CARLOTTI

    2011-01-01

    This paper presents two comparisons or tests for a Lagrangian model of zooplankton dispersion: numerical schemes and time steps. Firstly, we compared three numerical schemes using idealized circulations. Results show that the precisions of the advanced Adams-Bashfold-Moulton (ABM) method and the Runge-Kutta (RK) method were in the same order and both were much higher than that of the Euler method. Furthermore, the advanced ABM method is more efficient than the RK method in computational memory requirements and time consumption. We therefore chose the advanced ABM method as the Lagrangian particle-tracking algorithm. Secondly, we performed a sensitivity test for time steps, using outputs of the hydrodynamic model, Symphonie. Results show that the time step choices depend on the fluid response time that is related to the spatial resolution of velocity fields. The method introduced by Oliveira et al. in 2002 is suitable for choosing time steps of Lagrangian particle-tracking models, at least when only considering advection.

  12. Environmental context determines community sensitivity of freshwater zooplankton to a pesticide

    International Nuclear Information System (INIS)

    The environment is currently changing worldwide, and ecosystems are being exposed to multiple anthropogenic pressures. Understanding and consideration of such environmental conditions is required in ecological risk assessment of toxicants, but it remains basically limited. In the present study, we aimed to determine how and to what extent alterations in the abiotic and biotic environmental conditions can alter the sensitivity of a community to an insecticide, as well as its recovery after contamination. We conducted an outdoor microcosm experiment in which zooplankton communities were exposed to the insecticide esfenvalerate (0.03, 0.3, and 3 μg/L) under different regimes of solar radiation and community density, which represented different levels of food availability and competition. We focused on the sensitivity of the entire community and analysed it using multivariate statistical methods, such as principal response curves and redundancy analysis. The results showed that community sensitivity varied markedly between the treatments. In the experimental series with the lowest availability of food and strongest competition significant effects of the insecticide were found at the concentration of 0.03 μg/L. In contrast, in the series with relatively higher food availability and weak competition such effects were detected at 3 μg/L only. However, we did not find significant differences in the community recovery rates between the experimental treatments. These findings indicate that environmental context is more important for ecotoxicological evaluation than assumed previously.

  13. The diel zooplankton motion at 1000 and 300 m depth

    Science.gov (United States)

    Ochoa, J.; Badan, A.; Candela, J.; Sheinbaum, J.

    2007-05-01

    A well known feature of a large fraction of the zooplankton in the 300 m near-surface layer is the daily vertical migration cycle, which is phase locked with the light cycle. Less documented is the similar cycle in deeper layers away from significant light. Here we show, based on direct measurements, the mean vertical velocity cycle for layers 170 m thick, one centered at 1000 m and another, for reference, at 300 m depth, in the central Gulf of Mexico. Averages over 473 days are computed timing each cycle with the sunrise and sunset. Both cycles are highly symmetrical odd functions where, in the deeper layer, the downward/upward migration is delayed/advanced relative to the upper layer by about 1 h 40 min. In the upper layer, the peak speeds are close to 40 mm/s, with corresponding vertical displacements about 250 m, and in the deeper layer the peak speeds are 10 mm/s with vertical displacements of approximately 120 m. In the upper layer, the peak downward motion occurs minutes before sunrise, wheras in the lower layer, the peak downward velocity occurs 1.5 hours after the sunrise. The peak upward velocities are found 1.5 hours before sunset in the deeper layer and just minutes after sunset in the upper layer. Therefore, the nightly permanence towards shallower water lasts longer, for about 3.5 hours, in the deeper layers than closer to surface.

  14. Zooplankton of Lake Orta after liming: an eleven years study

    Directory of Open Access Journals (Sweden)

    Andrea PASTERIS

    2001-02-01

    Full Text Available Lake Orta (N. Italy was severely polluted from 1927 by an effluent from a rayon factory, which discharged great amounts of ammonium nitrogen and copper into the lake. In the mid nineteen fifties, some plating factories also started dumping chromium and aluminum. As a result of ammonium oxidation, the lake became very acid and the concentration of metals in the waters reached very high values. Phytoplankton, zooplankton and fish disappeared suddenly from the lake which was by 1930 classified as “sterile”. Later on, about the fifties, a small population of Cyclops abyssorum re-colonised the lake together with some rotifers, in particular Hexarthra fennica. In mid eighties following the introduction of anti-pollution legislation, ammonium loads were greatly reduced and Daphnia obtusa was recorded. The lake waters however were still very acid, prompting the proposal of the Istituto Italiano di Idrobiologia to lime the lake with calcium carbonate to neutralise the excess acidity and reconstruct the alkaline reserve. This was done successfully from May 1989 to June 1990. pH values began to rise and in the same time the metal concentrations decreased, so that at present the lake waters are almost “normal”. In the meantime, due to the increased pH values, D. obtusa was replaced by D. longispina and, as toxic metal concentrations became lower, Megacyclops viridis, Bosmina longirostris, Diaphanosoma brachyurum, Keratella quadrata, Asplanchna priodonta. and other Brachionidae species appeared. Diaptomidae are still absent, except for some specimens of Arctodiaptomus wierzejskii.

  15. Zooplankton diversity across three Red Sea reefs using pyrosequencing

    Directory of Open Access Journals (Sweden)

    John Kenneth Pearman

    2014-07-01

    Full Text Available 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 utilised 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.

  16. 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.

  17. The Spatial Structure of Zooplankton Communities of Pedu Reservoir,Malaysia%The Spatial Structure of Zooplankton Communities of Pedu Reservoir, Malaysia

    Institute of Scientific and Technical Information of China (English)

    Amir Shah Ruddin Md Shah; Johan Ismail; Diana Latief; Wan Maznah Wan Omar

    2012-01-01

    A total of 22 species of zooplankton were identified from 8 sampling stations located in the limnetic zone of Pedu reservoir.The zooplankton community was dominated by rotifers (11 species),followed by cladocerans (9species) and copepods (2 species).Four species of zooplankton comprised of 3 rotifers,Brachionus quadridentata,Brachionus caudatus and Keratella cochlearis and one cladoceran,Ceriodaphnia cornuta were present at all sampling stations.Species richness was highest at Station 2 (17 species) followed by Station 4 and Station 8 (14 species),Station 5 (15 species),Station 7 (11 species),Station 6 (10 species),Station 3 (9 species) and Station 1 (7 species).With an exception of water transparency,all other water quality parameters such as temperature,dissolved oxygen,conductivity,pH and total dissolved solids were not significant when compared between sampling stations.The study found that station 5 which was located in a calm strait,protected from strong wave and wind was a suitable area for zooplankton growth and establishment.Factors supporting the findings included highest water transparency (3.4 m),rich in species numbers (15 species),high diversity index (0.950) and evenness index (0.808).

  18. The geochemical role of phyto- and zooplankton in the extraction of chemical elements from water

    Science.gov (United States)

    Chebotina, M. J.; Polyakov, E. V.; Guseva, V. P.; Khlebnikov, N. A.; Surikov, V. T.

    2011-08-01

    This paper provides for the first time comparative assessment of the contents of 70 chemical elements occurring in the aquatic environment in water, phytoplankton, and zooplankton. The assessment was made using modern highly sensitive methods. The studies were performed at Beloyarskoe Reservoir, a manmade freshwater lake situated in the Middle Urals that has been studied in detail. The chemical elements were ranked in groups differing in the accumulation coefficient (AC) values for the phyto- and zooplankton. The comparison revealed that for the vast majority of chemical elements, the AC values were higher in zooplankton (53, or 76%) than in phytoplankton (17, or 24%). The average AC values for zooplankton (˜740 000) exceeded that for phytoplankton (˜68 000) by more than 10 times. It was found that some elements had very high AC values in zooplankton compared to phytoplankton. For instance for Nb, the ratio ACzoo/ACphyto was 1 200 000; for B, Ta, Sn, Lu, U, 300 000-500 000; for Sb and Y, 100 000-130 000; for La and Nd, 80 000-85 000; for Mo, Cd, Pr, Gd, Dy, Sc, Se, Bi, 20 000-30 000; and for Pd, Hf, Sm, Sb, Er, As, 10 000-20 000. It is concluded that zooplankton is sometimes more suitable for the biogeochemical indication of the pollution of natural water bodies, because the AC values for most elements are much higher in zooplankton than in phytoplankton and the total plankton. Considering the high assimilability of microelements and radionuclides, the plankton may serve not only as an indication but also as the mean of regulated purification of waterbodies from these elements.

  19. 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.

  20. Seasonal Distribution of Zooplankton in Mahanadi Estuary (Odisha, East Coast of India: A Taxonomical Approach

    Directory of Open Access Journals (Sweden)

    C. R. Panda

    2013-01-01

    Full Text Available Study of coastal and estuarine water is important as they act as a medium of exchange of materials between land and ocean. Mahanadi estuarine system forms the largest system of its kind in Odisha. Zooplankton, the secondary producers plays a vital role in the hydrobiology and food chain regulation. The zooplankton diversity of Mahanadi estuary (Odisha was investigated during postmonsoon (December 2009, premonsoon (April 2010 and monsoon (July 2010. Important hydrographical parameters such as water temperature, salinity, pH and dissolved oxygen, NO2 (nitrite, NO3 (nitrate, NH4 (ammonia, TN (total nitrogen, PO4 (phosphate, TP (total phosphorous and SiO4 (silicate were measured during the present study along with the study of the qualitative and quantitative aspects of zooplankton. Zooplankton population dominated by copepod at all the stations in all the seasons except during low tide of premonsoon season where caridean larvae were dominant. In total, 86 species of zooplankton, mostly belonging to Crustacea, Chaetognatha, Mollusca, Polychaeta, Cnidaria, Ctenophora, Protozoa, Larvacea among the holoplankton and 16 different types of larval forms were encountered. The population density ranged from 52 to 885 org. m-3 with highest density during high tide of post-monsoon i.e., 885 org. m-3. The copepods like Subeucalanus mucronatus, Subeucalanus subcrassus, Sapphirina maculosa, Sapphirina auronitens are recorded for the first time from marine and estuarine ecosystem of Odisha. Presence of 16 different crustacean dominated larval forms signifies the conduciveness of estuary during the whole period for breeding and spawning of shell fishes in the estuary. During the present study, zooplankton population density was positively related with zooplankton biomass.

  1. German Bight residual current variability on a daily basis: principal components of multi-decadal barotropic simulations

    Science.gov (United States)

    Callies, Ulrich; Gaslikova, Lidia; Kapitza, Hartmut; Scharfe, Mirco

    2016-08-01

    Time variability of Eulerian residual currents in the German Bight (North Sea) is studied drawing on existing multi-decadal 2D barotropic simulations (1.6 km resolution) for the period Jan. 1958-Aug. 2015. Residual currents are calculated as 25 h means of velocity fields stored every hour. Principal component analysis (PCA) reveals that daily variations of these residual currents can be reasonably well represented in terms of only 2-3 degrees of freedom, partly linked to wind directions. The daily data refine monthly data already used in the past. Unlike existing classifications based on subjective assessment, numerical principal components (PCs) provide measures of strength and can directly be incorporated into more comprehensive statistical data analyses. Daily resolution in particular fits the time schedule of data sampled at the German Bight long-term monitoring station at Helgoland Roads. An example demonstrates the use of PCs and corresponding empirical orthogonal functions (EOFs) for the interpretation of short-term variations of these local observations. On the other hand, monthly averaging of the daily PCs enables to link up with previous studies on longer timescales.

  2. Anthropogenic nutrient sources rival natural sources on small scales in the coastal waters of the Southern California Bight

    KAUST Repository

    Howard, Meredith D. A.

    2014-01-26

    Anthropogenic nutrients have been shown to provide significant sources of nitrogen (N) that have been linked to increased primary production and harmful algal blooms worldwide. There is a general perception that in upwelling regions, the flux of anthropogenic nutrient inputs is small relative to upwelling flux, and therefore anthropogenic inputs have relatively little effect on the productivity of coastal waters. To test the hypothesis that natural sources (e.g., upwelling) greatly exceed anthropogenic nutrient sources to the Southern California Bight (SCB), this study compared the source contributions of N from four major nutrient sources: (1) upwelling, (2) treated wastewater effluent discharged to ocean outfalls, (3) riverine runoff, and (4) atmospheric deposition. This comparison was made using large regional data sets combined with modeling on both regional and local scales. At the regional bight-wide spatial scale, upwelling was the largest source of N by an order of magnitude to effluent and two orders of magnitude to riverine runoff. However, at smaller spatial scales, more relevant to algal bloom development, natural and anthropogenic contributions were equivalent. In particular, wastewater effluent and upwelling contributed the same quantity of N in several subregions of the SCB. These findings contradict the currently held perception that in upwelling-dominated regions anthropogenic nutrient inputs are negligible, and suggest that anthropogenic nutrients, mainly wastewater effluent, can provide a significant source of nitrogen for nearshore productivity in Southern California coastal waters.

  3. The role of Callionymus lyra (L.) and C. reticulatus in the life cycle of Lernaeocera lusci in Belgian coastal waters (Southern Bight of the North Sea)

    NARCIS (Netherlands)

    Van Damme, P.A.; Maertens, D.; Arrumm, A.; Hamerlynck, O.; Ollevier, F.

    1993-01-01

    A survey of the dragonet Callionymus lyra and the reticulated dragonet C. reticulatus from Belgian coastal waters (Southern Bight of the North Sea) in June 1991 revealed 34% of dragonets infected with 1–7 Lernaeocera lusci. This same parasite infected 9% of the reticulated dragonets (mean intensity

  4. Effect of nutrient availability on the uptake of PCB congener 2,2',6,6'-tetrachlorobiphenyl by a diatom (Stephanodiscus minutulus) and transfer to a zooplankton (Daphnia pulicaria).

    Science.gov (United States)

    Lynn, Scott G; Price, David J; Birge, Wesley J; Kilham, Susan S

    2007-06-01

    The objective of this study was to examine the importance of nutrient status of a diatom (Stephanodiscus minutulus) to the uptake of PCB congener #54 (2,2',6,6'-tetrachlorobiphenyl) and the subsequent transfer of PCB to a pelagic grazing zooplankton (Daphnia pulicaria). The algae, which were grown under different nutrient treatments, were then fed to a zooplankton to examine the subsequent food chain transfer of PCB. Algal cultures were grown for at least 2 weeks in a steady state condition in (1) non-limiting, (2) low-Si, (3) low-N or (4) low-P media. Steady state algal cultures were dosed with 0.2 microg L(-1) PCB and were sampled for PCB uptake after 24h. D. pulicaria were allowed to graze on these same cultures for 48 h before being analyzed for PCB body burdens. Low-Si (68% or 0.135 microg L(-1) of PCB) and low-P cultures (62%) had significantly higher percentage uptake of total PCB than the non-limiting (55%) or low-N (52%) treatments. When these values were divided by biochemical or elemental parameters, PCB per lipids (microg microg(-1)) had one of the lowest coefficients of variation (CV) across the four treatments, indicating their importance in PCB uptake. When equal biovolumes of the four different treatment cultures were fed to zooplankton, both the low-N (13.9 ng PCB mg wet weight(-1)) and the low-P (9.6 ng PCB mg wet weight(-1)) grazing D. pulicaria had significantly higher PCB per wet weight than the low-Si (5.6 ng PCB mg wet weight(-1)) and non-limited (2.6 ng PCB mg wet weight(-1)) grazing D. pulicaria. There were no significant differences between algal nutrient treatments in PCB per wet weight of zooplankton grazing on clean algal food in PCB contaminated media. This study indicates that uptake of PCB by phytoplankton can be significantly altered by nutrient availability which subsequently affects transfer to zooplankton, potentially through such responses as grazing rate and lipid assimilation.

  5. Seasonal dynamics and grazing rate of zooplankton in Yueqing Bay,China

    Institute of Scientific and Technical Information of China (English)

    LIU Zhensheng; WANG Chunsheng; ZHANG Zhinan; CAI Yuming; ZHANG Dongsheng

    2006-01-01

    The species composition,biomass,abundance,and species diversity of zooplankton were determined for samples collected from August 2002 to May 2003 from 14 stations in Yueqing Bay,China.Phytoplankton growth rate and microzooplankton grazing rate were obtained by using the dilution method developed by Landry and Hassett.The spatial and temporal variations of zooplankton and its relationship with environmental factors were also analyzed.The results showed that the zooplankton in the Yueqing Bay could be divided into four ecotypes,namely coastal low saline species,estuary brackish water species,offshore warm water species,and eurytopic species.A total of 75 species of zooplankton belonging to 56 genera and 17 groups of pelagic larva were identified in the Yueqing Bay.The coastal low saline species was the dominant ecotype in the study area,and the dominant species were Labidocera euchaeta,Acartia pacifica,Acrocalanus gibber,Pseudeuphausia sinica,and Sagitta bedoti among others.There was considerable seasonal variation in zooplankton biomass and abundance in the surveyed areas.The peak biomass appeared in August,descending in November and in May,and the lowest biomass appeared in February.Similarly,the highest abundance of zooplankton was observed in August,with the abundance descending in the following months:May,November,and February.There were similar horizontal distribution patterns for the biomass and the abundance of zooplankton.They both increased from the upper to the lower bay in February and May,but decreased from the upper to the lower bay in August.Biomass and abundance were evenly distributed in the Yueqing Bay in November.Moreover,there was marked seasonal variation in the species diversity of zooplankton,which conformed to the abundance of zooplankton.Results of the dilution experiments indicated that there was grazing pressure of microzooplankton on phytoplankton in the Yueqing Bay throughout the year though the rate of microzooplankton grazing on

  6. Body growth and reproduction of individuals of the sciaenid fish Stellifer rastrifer in a shallow tropical bight: A cautionary tale for assumptions regarding population parameters

    Science.gov (United States)

    Pombo, Maíra; Denadai, Márcia Regina; Turra, Alexander

    2013-05-01

    Knowledge of population parameters and the ability to predict their responses to environmental changes are useful tools to aid in the appropriate management and conservation of natural resources. Samples of the sciaenid fish Stellifer rastrifer were taken from August 2003 through October 2004 in shallow areas of Caraguatatuba Bight, southeastern Brazil. The results showed a consistent presence of length-frequency classes throughout the year and low values of the gonadosomatic index of this species, indicating that the area is not used for spawning or residence of adults, but rather shelters individuals in late stages of development. The results may serve as a caveat for assessments of transitional areas such as the present one, the nursery function of which is neglected compared to estuaries and mangroves. The danger of mismanaging these areas by not considering their peculiarities is emphasized by using these data as a study case for the development of some broadly used population-parameter analyses. The individuals' body growth parameters from the von Bertalanffy model were estimated based on the most common approaches, and the best values obtained from traditional quantification methods of selection were very prone to bias. The low gonadosomatic index (GSI) estimated during the period was an important factor in stimulating us to select more reliable parameters of body growth (L∞ = 20.9, K = 0.37 and Z = 2.81), which were estimated based on assuming the existence of spatial segregation by size. The data obtained suggest that the estimated mortality rate included a high rate of migration of older individuals to deeper areas, where we assume that they completed their development.

  7. Zooplankton biomass estimated from digitalized images in Antarctic waters: A calibration exercise

    Science.gov (United States)

    HernáNdez-León, Santiago; Montero, Irene

    2006-05-01

    The direct measurement of zooplankton biomass following the different analytical procedures normally requires the destruction of the samples. The use of conversion factors to estimate biomass from nondestructive methods is still a challenge. The widespread use of image analyzers and optical counters in biological oceanography provides a useful tool to measure the abundance and size spectrum of zooplanktonic organisms in real or quasi-real time. Both methodologies measure the equivalent spherical diameter and/or the body area of organisms. In order to estimate biomass from the highly valuable information generated by the size spectrum of the sample, we measured the relationship between individual body area and individual biomass of the most common species and groups of zooplankton in Antarctic waters. The slope of the regression for each different species and groups of taxa was not significantly different from that obtained by pooling all taxa, thus providing a general relationship for the entire size spectrum of zooplankton. The biomass estimated from the body area spectrum of samples obtained around the Antarctic Peninsula agreed with other measurements of biomass in the region. The proposed conversion factor could provide for rapid estimates of biomass of net-collected zooplankton from imaging devices or optical plankton counters.

  8. Diurnal Changes of Zooplankton Community Reduction Rate at Lake Outlets and Related Environmental Factors

    Science.gov (United States)

    Czerniawski, Robert; Sługocki, Łukasz

    2016-01-01

    The reduced zooplankton abundance at the outlet sections of lakes depends on the occurrence of preying fry. Therefore, light conditions can play a major role in the drift of zooplankton along river outlets. The aim of this study was to determine the influence of diurnal light conditions on the decline of zooplankton densities at lake outlets. Photosynthetically active radiation (PAR) levels were measured to determine their effect on the rate of reduced zooplankton abundance. Cladocerans and copepods showed a significantly greater reduction in abundance than rotifers and nauplii. A significant positive relationship was observed between the PAR levels and the reduced abundance of Asplanchna sp., small cladocerans, large cladocerans and Copepoda at the lake outlets. Among the rotifers, small pelagic rotifers drifted the farthest at all hours of the day. Large crustaceans, especially the large cladocerans and copepodites and adult copepods, had the lowest chance of dispersing over a wide area. Our results indicate that light conditions play an important role in the reduction of zooplankton abundance at lake outlets and have an indirect influence on the downstream food web. PMID:27392017

  9. Zooplankton diversity and distribution in a deep and anoxic Mediterranean coastal lake

    Directory of Open Access Journals (Sweden)

    G. KEHAYIAS

    2013-04-01

    Full Text Available The variation of the smaller size fraction of zooplankton was investigated during a two-year period in a brackish deep and anoxic coastal lake of western Greece (Aitoliko, along with the specific environmental characteristics of this ecosystem. The zooplanktonic community comprised a relatively small number of taxa and it was dominated by brackish-water calanoid copepods (Paracartia latisetosa, Calanipeda aquaedulcis and in certain periods by rotifers and tintinnids. The zooplankton abundance showed an increase in the warmer period starting from late spring and reached maximum values in July. In the well oxygenated surface layer, temperature was the most important parameter influencing the seasonal cycles of all groups. In contrast, the oxygen depletion a few meters under the surface affected the vertical distribution of most of the zooplankton groups, which were found restricted in the surface layer especially from spring until autumn. Only the meroplanktonic larvae of polychaetes presented increased proportions in the deeper layers. Salinity has not significantly influenced the zooplanktonic assemblages. The results point out the degraded status of the Aitoliko basin where the hypoxic/anoxic layers resulted to a high portion of dead organic material identified as copepod carcasses, and underlines the necessity of monitoring of this ecosystem.

  10. The relation between distribution of zooplankton and salinity in the Changjiang Estuary

    Institute of Scientific and Technical Information of China (English)

    GAO Qian; XU Zhaoli; ZHUANG Ping

    2008-01-01

    Seasonal netzplankton samples from stations in the Changjiang (Yangtze River) Estuary were collected from May,2004 to February,2005.The dominant species and their contribution to the total zooplankton abundance were determined.Moreover,the relationship between the salinity and abundance was studied with stepwise linear regression.During the whole year,the salinity was positively correlated with the abundance,while the temperature,negatively.Linear regression analysis showed also a high positive correlation with salinity for total abundance in August and November,while in February and May,no obvious relations were found.The most abundant community was composed of neritic and brackish-water species.The North Passage (NP) (salinity<5) was greatly diluted by freshwater while the North Branch (NB) was brackish water with salinity range of 12-28.Consequently,clear decline in abundance of zooplankton was along the estuarine haloclines from the maximum in the area of high salinity to the minimum in the limnetic zone.Total zooplankton abundance and biomass were lower in NP than the NB in all seasons.In short,the salinity influenced the abundance of each species of zooplankton,and ultimately determined the total abundance of zooplankton.Furthermore,a winter peak in the abundance existed,which might be caused by the flourishing of Sinocalanus sinensis,a widely distributed species in the Changjiang Estuary.

  11. Vertical distribution of zooplankton in the epipelagic zone off Sharm El-Sheikh, Red Sea, Egypt

    Directory of Open Access Journals (Sweden)

    Mahnoud Hassan Hanafi

    2012-06-01

    Full Text Available The purpose of the present study was to track the seasonal vertical distribution of zooplankton abundance in the epipelagic zone off Sharm El-Sheikh, Red Sea. Zooplankton samples were collected seasonally within the depth ranges of 0-25, 25-50, 50-75, 75-100 m at a single station off Sharm El-Sheikh City. The present study is a trial to expand knowledge about the structure as well as the vertical distribution of the epipelagic zooplankton community in the Gulf of Aqaba in general and in its southern part in particular. The results indicate the occurrence of 52 copepod species and several species of other planktonic groups in the study area; the zooplankton standing crop fluctuated between 1124 and 4952 organisms m-3. Copepods appeared to be the predominant component, forming an average of 86.5% of the total zooplankton count, and with other groups demonstrated a markedly different seasonal vertical distribution. Twelve bathypelagic copepod species were reported during the present study, and five species were new to the area, having migrated northwards from the main basin of the Red Sea.

  12. Water quality and zooplankton in tanks with larvae of Brycon Orbignyanus (Valenciennes, 1949).

    Science.gov (United States)

    Sipaúba-Tavares, L H; Alvarez, E J da S; Braga, F M de S

    2008-02-01

    Due to the importance of water variables conditions and available food in the development and survival of fish larvae, the current research evaluates the effects of two different food treatments (ration + zooplankton and only zooplankton) and water quality in tanks with Brycon orbignyanus larvae. Total water transparency (45 cm) has been mainly associated with short residence time, continuous water flow and shallowness. Dissolved oxygen ranged between 1.32 and 7.00 mg.L(-1) in tanks with ration + zooplankton and between 1.82 and 7.60 mg.L(-1) in tanks with only zooplankton treatments. Nutrients were directly affected by the addition of ration in water, with the exception of nitrite. Ten Rotifera species were found represented by high densities, ranging between 8.7 x 10(5) and 1.3 x 10(6) org.m(-3), throughout the experimental period (January to March/1996). Cladocera had the lowest density in the four tanks under analysis and ranged between 4.7 x 10(4) and 2.1 x 10(5) org.m(-3) for the six species. Diaphanosoma birgei has been classified as the most frequent species. Since ration + zooplankton produced better larvae yield, this treatment is recommended for Brycon orbignyanus larvae.

  13. Terrestrially derived dissolved organic matter in the chesapeake bay and the middle atlantic bight

    Science.gov (United States)

    Mitra, Siddhartha; Bianchi, Thomas S.; Guo, Laodong; Santschi, Peter H.

    2000-10-01

    Concentrations of lignin-phenols were analyzed in high molecular weight dissolved organic matter (0.2 μm > HMW DOM > 1 kDa) isolated from surface waters of the Chesapeake Bay (C. Bay), and surface and bottom waters of the Middle Atlantic Bight (MAB). The abundance of lignin-phenols in HMW DOM was higher in the C. Bay (0.128 ± 0.06 μg L -1) compared to MAB surface waters (0.016 ± 0.004 μg L -1) and MAB bottom waters (0.005 ± 0.003 μg L -1). On an organic carbon-normalized basis, lignin-phenol abundances in the HMW DOM (i.e., Λ 6), were significantly higher ( p vanillin (Ad/Al) V in HMW DOM, indicative of lignin decay, ranged from 0.611 to 1.37 in C. Bay, 0.534 to 2.62 in MAB surface waters, and 0.435 to 1.96 in MAB bottom water. Ratios of S/V and (Ad/Al) V showed no significant differences between each environment, providing no evidence of any compositionally distinct input of terrestrial organic matter into each environment. When considering depth profiles of suspended particulate matter in the MAB, with C:N ratios, and bulk radiocarbon ages and stable carbon isotopic values in HMW DOM isolated from these areas, two scenarios present themselves regarding the sources and transport of terrestrially derived HMW DOM in the MAB. Scenario #1 assumes that a low amount of refractory terrestrial organic matter and old DOC are uniformly distributed in the oceans, both in surface and bottom waters, and that primary production in surface waters increases DOC with low lignin and younger DOC which degrades easily. In this case, many of the trends in age and biomarker composition likely reflect general patterns of Atlantic Ocean surface and bottom water circulation in the area of the MAB. Scenario 2 assumes terrestrial organic matter in bottom waters of the MAB may have originated from weathered shelf and slope sediments in nearshore areas via a combination of mechanisms (e.g., diffusion, recent resuspension events, and/or desorption of DOM from riverine POM buried deep

  14. Atlantic surfclam connectivity within the Middle Atlantic Bight: Mechanisms underlying variation in larval transport and settlement

    Science.gov (United States)

    Zhang, Xinzhong; Munroe, Daphne; Haidvogel, Dale; Powell, Eric N.

    2016-05-01

    Larval transport and settlement have been shown in various studies to be essential in determining population abundance and connectivity for benthic invertebrates. This transport is influenced by both the physical environment and biological behavior. The Atlantic surfclam, Spisula solidissima, is a commercially important benthic invertebrate fishery species along the U.S northeastern coast. In this study, a physical circulation model is coupled to a surfclam larval model to investigate the dynamics of larval transport and settlement within the Middle Atlantic Bight (MAB) shelf in 2006. The main physical mechanisms causing variability in larval transport and settlement are also examined. Model results show that surfclam larvae released from July to early October experience relatively larger settlement rates, due to higher average temperatures experienced by larvae. Larval along-shore transport exhibits a mean down-coast pattern following the coastal current from the northeast to the southwest, with most high-frequency (period of 2-10 days) variations caused by fluctuations in the along-shore surface wind stress, and with seasonal variations speculated to be driven mainly by changes in the across-shelf density gradient. Larval across-shelf movement is highly correlated with the along-shore surface wind stress mediated by coastal upwelling and downwelling episodes, but the correlation is further dependent on the vertical distribution of the larvae, particularly their position relative to the thermocline. Most surfclam larvae released from the Middle Atlantic shelf stay below the thermocline and experience a net onshore transport during the summer-stratified season when upwelling-favorable wind forcing dominates. A proposed critical value of water temperature at the thermocline successfully regulates the observed patterns of vertical distribution of surfclam larvae and their across-shelf movement off the New Jersey and South Virginia shelves; that is, when the water

  15. Characterizing Wave- and Current-Induced Bottom Shear Stress: U.S. Middle Atlantic Bight

    Science.gov (United States)

    Dalyander, S.; Butman, B.

    2011-12-01

    The combined action of waves and currents at the seabed creates bottom shear stress, impacting local geology, habitat, and anthropogenic use. In this study, a methodology is developed to characterize the magnitude of benthic disturbance based on spatially and seasonally-resolved statistics (mean, standard deviation, 95th percentile) of wave-current bottom shear stress. The frequency of stress forcing is used to distinguish regions dominated by storms (return interval longer than 33 hours) from those dominated by the tides (periods shorter than 33 hours). In addition, the relative magnitude of the contribution to stress from waves, tides, and storm-driven currents is investigated by comparing wave stress, tidal current stress, and stress from the residual current (currents with tides removed), as well as through cross-correlation of wave and current stress. The methodology is applied to numerical model time-series data for the Middle Atlantic Bight (MAB) off the U.S. East Coast for April 2010 to April 2011; currents are provided from the Integrated Ocean Observing System (IOOS) operational hydrodynamic forecast Experimental System for Predicting Shelf and Slope Optics (ESPreSSO) and waves are provided from a Simulating WAves Nearshore (SWAN) hindcast developed for this project. Spatial resolution of the model is about 5 km and time-series wave and current data are at 1 and 2-hours respectively. Regions of the MAB delineated by stress characteristics include a tidally-dominated shallow region with relative high stress southeast of Massachusetts over Nantucket Shoals; a coastal band extending offshore to about 30 m water depth dominated by waves; a region dominated by waves and wind-driven currents offshore of the Outer Banks of North Carolina; and a low stress region southeast of Long Island, approximately coincident with an area of fine-grained sediments called the "Mud Patch". Comparison of the stress distribution with surface sediment texture data shows that

  16. 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 influen

  17. 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...

  18. Zooplankton data collected from SWIMMER/DIVER in Coastal Waters of Hawaii;01 June 1994 to 31 December 1995 (NODC Accession 9800174)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Coastal Waters of Hawaii from SWIMMER / DIVER. Data were collected from 01 June 1994 to 31 December...

  19. 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...

  20. DNA Barcoding of Metazoan Zooplankton Copepods from South Korea

    Science.gov (United States)

    Ryu, Shi Hyun; Kim, Sang Ki; Lee, Jin Hee; Lim, Young Jin; Lee, Jimin; Jun, Jumin; Kwak, Myounghai; Lee, Young-Sup; Hwang, Jae-Sam; Venmathi Maran, Balu Alagar; Chang, Cheon Young; Kim, Il-Hoi; Hwang, Ui Wook

    2016-01-01

    Copepods, small aquatic crustaceans, are the most abundant metazoan zooplankton and outnumber every other group of multicellular animals on earth. In spite of ecological and biological importance in aquatic environment, their morphological plasticity, originated from their various lifestyles and their incomparable capacity to adapt to a variety of environments, has made the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of cryptic or sibling species based on DNA sequence data. We examined sequence variation of a partial mitochondrial cytochrome C oxidase I gene (COI) from 133 copepod individuals collected from the Korean Peninsula, in order to identify and discriminate 94 copepod species covering six copepod orders of Calanoida, Cyclopoida, Harpacticoida, Monstrilloida, Poecilostomatoida and Siphonostomatoida. The results showed that there exists a clear gap with ca. 20 fold difference between the averages of within-specific sequence divergence (2.42%) and that of between-specific sequence divergence (42.79%) in COI, suggesting the plausible utility of this gene in delimitating copepod species. The results showed, with the COI barcoding data among 94 copepod species, that a copepod species could be distinguished from the others very clearly, only with four exceptions as followings: Mesocyclops dissimilis–Mesocyclops pehpeiensis (0.26% K2P distance in percent) and Oithona davisae–Oithona similis (1.1%) in Cyclopoida, Ostrincola japonica–Pseudomyicola spinosus (1.5%) in Poecilostomatoida, and Hatschekia japonica–Caligus quadratus (5.2%) in Siphonostomatoida. Thus, it strongly indicated that COI may be a useful tool in identifying various copepod species and make an initial progress toward the construction of a comprehensive DNA barcode database for copepods inhabiting the Korean Peninsula. PMID:27383475

  1. Effects of the proximal factors on the diel vertical migration of zooplankton in a plateau meso-eutrophic Lake Erhai, China

    OpenAIRE

    Cuilin Hu; Shengrui Wang; Longgen Guo; Ping Xie

    2014-01-01

    To study the proximal factors inducing diel vertical migration (DVM) in large and small zooplankton species in a plateau lake in China, we investigated the DVM of crustacean zooplankton in lake Erhai bimonthly from November 2009 to September 2010. We hypothesized that the factors affecting DVM behaviour in different-sized zooplankton were different. A linear regression was used to assess the relationships between environmental variables and the vertical distribution of zooplankton. All crusta...

  2. 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.

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

    Institute of Scientific and Technical Information of China (English)

    杨宇峰; 王肇鼎; 潘明祥; 焦念志

    2002-01-01

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

  4. Variability of spatial and temporal distribution of zooplankton communities at Matrouh beaches, south-eastern Mediterranean Sea, Egypt

    Directory of Open Access Journals (Sweden)

    Sawsan M. Aboul Ezz

    2014-01-01

    Full Text Available The objectives of this work are to determine the main environmental drivers of zooplankton variability in water of Matrouh beach, south-eastern Mediterranean Sea and to evaluate the differences in zooplankton abundance and population structure in relation to chemical and biological parameters. Samples were collected seasonally from summer 2009 to summer 2010 at 10 sampling beaches. The zooplankton community was characterized by its high variability, and lower diversity. Zooplankton variability primarily responded to seasonal changes in water temperature and variation in salinity. In total, 49 zooplankton species were quantified; most of them were protozoans (22 species and copepods (14 species. The average zooplankton abundance was 36.0 × 103 ind. m−3, where copepods were dominant, making up 72.4% of the total population. Protozoa formed the second group, comprising 11.7%. Differences in species diversity were analysed in a zooplankton community, where the dominance of a single species was frequent. The Shannon–Wiener Diversity Index classified Matrouh water as being between moderately polluted and polluted, whereas the WQI demonstrated that it was between good and excellent. It can be concluded that, the index based on WQI is currently more suitable than the zooplankton species index for assessing the quality of water of Matrouh beaches.

  5. Temperature and other data collected using visual observations and other instruments in the Mid-Atlantic Bight and other Seas from GYRE from 01 August 1985 to 26 May 1990 (NODC Accession 9300074)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and other data were collected using visual observations, bottle casts, and other instruments from GYRE and other platforms in the Mid-Atlantic Bight and...

  6. Physical, taxonomic code, and other data from current meter and other instruments in New York Bight from DOLPHIN and other platforms; 14 March 1971 to 03 August 1975 (NODC Accession 7601385)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, taxonomic code, and other data were collected using current meter and other instruments from DOLPHIN and other platforms in New York Bight. Data were...

  7. Physical trajectory profile data from glider ru23 deployed by Rutgers, the State University of New Jersey in the Mid-Atlantic Bight from 2012-10-25 to 2012-11-05 (NCEI Accession 0145723)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Slocum glider ru23 was deployed prior to the movement of Hurrican Sandy into the Mid-Atlantic Bight and was deployed to sample the sub-surface waters during the...

  8. HYDROCARBONS - TOTAL RESOLVED, CAS (CHEMICAL ABSTRACTS SERVICE) PARAMETER CODES and PCB, and other data from UNKNOWN in the New York Bight on 1901-01-01 (NODC Accession 8600271)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This submission contains the master data set assembled in a study called "Contaminant Body Burdens, Variability and Monitoring Implications for the New York Bight"....

  9. Current, temperature, backscatter, and other data from bottom instrument packages deployed from the RV Oceanus and other platforms in support of sediment transport observation in the Middle Atlantic Bight from 11 December 1975 to 30 October 1980 (NODC Accession 0066005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A series of studies to assess environmental hazards to petroleum development in the Middle Atlantic Bight. Long-term observations of currents and near-bottom...

  10. Diel variation and trophic structure in coral-reef zooplankton of Peninsular Malaysia

    OpenAIRE

    Nakajima, Ryota; Toda, Tatsuki; Yoshida, Teruaki; Othman, Bin Haji Ross

    2006-01-01

    Biomass in zooplankton (>100μm) and particulate organic matter (POM) (0.7-100μm) was investigated every 3 hours for two days at the fringing reef of Redang and Tioman Island, the east coast of Peninsular Malaysia. The zooplankton was size-fractionated into three fractions (100-200μm, 200-335μm, and >335μm) and POM was divided into two size-fractions (0.7-35 and 35-100μm). The POM (0.7-100μm) accounted for more than 95% of the total biomass (POM+zooplankton) in the water column. The largest si...

  11. Size and species diversity of zooplankton communities in fluctuating Mediterranean salt marshes

    Science.gov (United States)

    Brucet, Sandra; Boix, Dani; López-Flores, Rocío; Badosa, Anna; Quintana, Xavier D.

    2006-04-01

    Differences in size and species diversity were analysed in a zooplankton community of a Mediterranean salt marsh (Empordà wetlands, NE Iberian Peninsula), where the dominance of a single species was frequent. In the permanent salt marsh, species diversity and size diversity had similar patterns along zooplankton succession. In the temporary salt marsh species diversity was high after flooding and diminished once water inputs ceased. As species diversity declined size diversity increased. Eventually, one species of calanoid dominated the zooplankton community. The high size diversity in situations of calanoid dominance was possibly due to the co-occurrence of different developmental stages, each of which have different diets. Size diversity would thus indicate trophic niche segregation among different sizes. The combined use of species and size diversity values allows the identification of the successional phases.

  12. 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.

  13. Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter.

    Science.gov (United States)

    Last, Kim S; Hobbs, Laura; Berge, Jørgen; Brierley, Andrew S; Cottier, Finlo

    2016-01-25

    In extreme high-latitude marine environments that are without solar illumination in winter, light-mediated patterns of biological migration have historically been considered non-existent [1]. However, diel vertical migration (DVM) of zooplankton has been shown to occur even during the darkest part of the polar night, when illumination levels are exceptionally low [2, 3]. This paradox is, as yet, unexplained. Here, we present evidence of an unexpected uniform behavior across the entire Arctic, in fjord, shelf, slope and open sea, where vertical migrations of zooplankton are driven by lunar illumination. A shift from solar-day (24-hr period) to lunar-day (24.8-hr period) vertical migration takes place in winter when the moon rises above the horizon. Further, mass sinking of zooplankton from the surface waters and accumulation at a depth of ∼50 m occurs every 29.5 days in winter, coincident with the periods of full moon. Moonlight may enable predation of zooplankton by carnivorous zooplankters, fish, and birds now known to feed during the polar night [4]. Although primary production is almost nil at this time, lunar vertical migration (LVM) may facilitate monthly pulses of carbon remineralization, as they occur continuously in illuminated mesopelagic systems [5], due to community respiration of carnivorous and detritivorous zooplankton. The extent of LVM during the winter suggests that the behavior is highly conserved and adaptive and therefore needs to be considered as "baseline" zooplankton activity in a changing Arctic ocean [6-9]. VIDEO ABSTRACT. PMID:26774785

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

    Science.gov (United States)

    Le Quéré, Corinne; Buitenhuis, Erik T.; Moriarty, Róisín; Alvain, Séverine; Aumont, Olivier; Bopp, Laurent; Chollet, Sophie; Enright, Clare; Franklin, Daniel J.; Geider, Richard J.; Harrison, Sandy P.; Hirst, Andrew G.; Larsen, Stuart; Legendre, Louis; Platt, Trevor; Prentice, I. Colin; Rivkin, Richard B.; Sailley, Sévrine; Sathyendranath, Shubha; Stephens, Nick; Vogt, Meike; Vallina, Sergio M.

    2016-07-01

    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 biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs): six types of phytoplankton, three types of zooplankton, and heterotrophic procaryotes. We improved the representation of zooplankton dynamics in our model through (a) the explicit inclusion of large, slow-growing macrozooplankton (e.g. krill), and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean high-nutrient low-chlorophyll (HNLC) region during summer. When model simulations do not include macrozooplankton grazing explicitly, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when there is no iron deposition from dust. When model simulations include a slow-growing macrozooplankton and trophic cascades among three zooplankton types, the high-chlorophyll summer bias in the Southern Ocean HNLC region largely disappears. Our model results suggest that the observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean 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.

  15. Trace metal concentrations in zooplankton from the eastern Arabian Sea and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; Balachandran, K.K.; Nair, M.; Joseph, T.; DineshKumar, P.K.; Achuthankutty, C.T.; Nair, K.K.C.; Pillai, N.G.K.

    from the data of the Bay of Bengal that coastal stations off Visakhapatnam transect recorded higher average val- ues for Ni in seawater and zooplankton (0.097 ppb and 49 ppm) followed by off Madras transect (0.08 ppb and 44 ppm). Simi- larly, from... from the Kerala coast. Average Cd values in seawater and in surface zooplankton of the coastal stations off Visakhapatnam (0.047 ppb and 41 ppm) and off Madras (0.041 ppb and 29 ppm) showed higher val- ues than offshore samples in the respective...

  16. Zooplankton diversity and abundance of mangrove ecosystem of Kali estuary, Karwar, west coast of India

    Directory of Open Access Journals (Sweden)

    V. Kumar

    2013-09-01

    Full Text Available The present study conducted at the mangrove ecosystem of Kali estuary. Samples were collected from the three fixed stations for the period of thirteen months from January 2008 to January 2009 at regular monthly interval to identify and quantify the abundance, taxonomy and relative ratio of phytoplankton and zooplankton. In the present study of species diversity of zooplankton groups in the mangrove area, composed of twelve groups comprising fifty two species major share comes from the copepods which comprises about seventeen species. Protozoa taxa comprised by five species, coelenterata and cladocera by two species each, ctenophore comprised by single species whereas the larval forms comprised by fourteen species.

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

    Directory of Open Access Journals (Sweden)

    Fasil Degefu

    2014-11-01

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

  18. Zooplankton from OTEC sites in the Gulf of Mexico and the Caribbean

    Energy Technology Data Exchange (ETDEWEB)

    Commins, M.L.; Horne, A.J.

    1979-06-01

    The spatial and temporal variations in the abundance of major classes of zooplankton were measured using standard methods, between June and October 1978, at two OTEC sites in the Gulf of Mexico and in the Caribbean near Puerto Rico. The usual oceanic patterns were found with highest numbers near the surface, especially at night, and lowest numbers at 800 to 1000 m. Absolute numbers varied considerably from site to site. As expected, copepods (usually divided between calanoids and cyclopoids) dominated the zooplankton at all sites.

  19. Species diversity and community structure of zooplankton in the Zhubi Atoll, Nansha Islands, South China Sea

    OpenAIRE

    Jianqiang Yin; Liangmin Huang; Kaizhi Li; Lanlan Xiong

    2011-01-01

    Coral reefs contain the highest biodiversity ecosystem on Earth. In order to improve our understanding of the biodiversity and zooplankton communities, zooplankton was sampled using vertical trawls with 169 μm and 505 μm planktonic nets at 10 stations (5 within lagoon and 5 on reef flat) and one continuous observatory station from the 5th to the 15th of May, 2004 in the Zhubi Atoll of the Nansha Islands. A total of 96 species and 17 groups of planktonic larvae were identified, among which the...

  20. Ecological evaluation of proposed reference sites in the New York Bight, Great South Bay, and Ambrose Light, New York

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, W.W.; Barrows, E.S.; Word, J.Q. [Battelle Marine Research Lab., Sequim, WA (United States)

    1996-10-01

    The current reference site used in evaluations of dredged material proposed for open water disposal in the New York Bight is the Mud Dump Reference Site. The sediment at this reference site is predominantly sand. The US Army Corps of Engineers New York District is considering designation of a new reference site that (1) includes a fine-grained component, believed to be necessary for adequate amphipod survival in laboratory tests, (2) better reflects the physical characteristics of the fine-grained sediment dredged from the New York/New Jersey Harbor and (3) is further removed from the Mud Dump Site than the current Mud Dump Reference Site. The Battelle Marine Science Laboratory was requested to characterize sediment collected from seven candidate reference sites during two study phases. This report presents the results of physical, chemical, and toxicological characterizations of sediment from these sites in comparisons with those of the original Mud Dump Reference Site.

  1. Influences of temperature and nutrients on Synechococcus abundance and biomass in the southern Mid-Atlantic Bight

    Science.gov (United States)

    Moisan, Tiffany A.; Blattner, Kristen L.; Makinen, Carla P.

    2010-07-01

    Synechococci are small (prokaryotes that play a significant ecological role in microbial food webs and are important contributors to carbon and nitrogen biogeochemical cycles. Under funding from NOAA and NASA, we developed a time series observatory to understand the seasonal variability of Synechococcus and other phytoplankton. Our goal is to understand the distribution and relative contribution of Synechococcus to the carbon cycle and how they relate to nutrients and temperature. Synechococcus in the southern Mid-Atlantic Bight exhibited a clear seasonal abundance pattern in both inshore and offshore waters—peaking in abundance (11×10 4 cells ml -1) during warm periods of summer. Synechococci were numerically important during periods of stratification when waters were warm and macronutrients were low. Using a simple algorithm to convert cellular volume to cellular carbon using image analysis, we estimated that Synechococcus cellular carbon ranged from 0.1 to 1.5 pg C per cell and was most significant compared to total particulate carbon in the summer peaking at ˜25% of the total carbon available. No direct correlations were found between Synechococcus abundance and nitrate, nitrite, ammonium, phosphate, and silicate. However, inshore Synechococcus abundance peaked at 10 4 cells ml -1 when nitrogen concentrations were lowest. Our results suggest that Synechococcus is adapted to warm temperatures and are capable of demonstrating rapid growth during summer when macronutrients are limiting. The ability of Synechococcus to take advantage of high summer temperatures, low nutrient concentrations and low light levels allows them to maintain a picoplankton community during periods of low detritus and nanophytoplankton is nutrient limited. Temperature-dependence is important in altering the size spectrum of the phytoplankton community and affects the carbon cycle on the Mid Atlantic Bight.

  2. Carbon and nitrogen stable isotope characteristics of particulate organic matter and zooplankton in Liuxihe Reservoir%流溪河水库颗粒有机物及浮游动物碳、氮稳定同位素特征

    Institute of Scientific and Technical Information of China (English)

    宁加佳; 刘辉; 古滨河; 刘正文

    2012-01-01

    zooplankton and hence to higher trophic levels, along several direct and indirect pathways. Because the isotope ratios of consumers reflect those of their diet, the δ13C and δ15N of zooplankton will be affected when isotopic composition of POM changes over time. In order to understand the factors influencing the seasonal variations incarbon and nitrogen stable isotopes of POM and zooplankton and to assess relationship between POM and zooplankton, especially the relative importance of autochthonous and allochthonous materials to zooplankton, δ13C and δ15N of POM and zooplankton were analyzed in Liuxihe Reservoir from May to December in 2008. As the results of relatively stable solar energy inputs and low trophic state, the seasonal amplitudes of δ13CPOM and δ15NPOM in Liuxihe Reservoir were small, displaying seasonal variations of 5. 1‰ and 2. 2‰ due to the monsoon climate and summer storms. δ13CPOM was high in May and July and then decreased dramatically. Precipitation had significant positive correlation with δ13CPOM, but there were no significant correlations between δ13CPOM and TN, TP and Chl a. Rainfall brought abundant allochthonous organic matters into the reservoir, resulting in high δ13CPOM in the wet period (May to July). The low δ13CPOM in the dry period (October and December) was likely attributed to the low growth rate of phytoplankton in these cold months. Conversely, there was a seasonal increase in δ15NP0M in general. Precipitation, TN, TP and Chl a have insignificant correlations with δ15NP0M. We speculated that external loadings, primary productivity and nitrogen fixation by cyanobacteria were likely responsible for the seasonal variation in δ15 NPOM in Liuxihe Reservoir. The variations of zooplankton δ13C and δ15N signatures were similar to POM, and there was a significant positive correlation between δ13C in zooplankton and δ13C in POM as well as between δ15N in zooplankton and δ15N in POM, which indicated that zooplankton used POM

  3. Validation of Open-Sea CRYOSAT-2 Data in SAR Mode in the German Bight

    Science.gov (United States)

    Dinardo, Salvatore; Benveniste, Jérôme; Fenoglio-Marc, Luciana; Scharroo, Remko

    This work aims to generate and validate the altimetric geophysical parameters measured by the CryoSat-2 in SAR Mode in the temporal interval 2011-2012 in the area of the German Bight at distance to coast larger than 10 Kilometers (open-sea). Instantaneous sea surface height (SSH), significant wave height (SWH) and wind speed at 10 meter from sea surface (U10), measured by CryoSat-2, are compared to in-situ measurements at platforms, buoys and tide gauges and to results from an operational circulation model run by the German Federal Maritime and Hydrographic Agency (BSH). The in-situ data were made available by the Wasser- und Schifffahrtsverwaltung des Bundes (WSV). These stations are part of a network of tide gauges and offshore platforms equipped with continuously operation Global Navigation Satellite System (GNSS) receivers. Since the coordinates of the zero point of the tide gauge are computed in the International Terrestrial Reference Frame (ITRF) the absolute comparison between sea level from tide gauge and altimetry is possible. The relevant in-situ data are sea level, wave and wind data. The CryoSat-2 Data have been Delay-Doppler processed as from the FBR (Full Bit Rate) Level 1A to Level 1B and subsequently re-tracked using the SAMOSA's SAR Echo Model (full solution) and a curve-fitting scheme based on Levenberg-Marquard Least Square Minimization Algorithm. Sea surface height, significant wave height and wind speed at 20 Hz and 1 Hz have been derived. The Delay-Doppler processing (L1B) and the re-tracking processing (L2) has been carried out by the EOP-SER Altimetry Team at ESA/ESRIN. Pseudo pulse-limited (PLRM) data derived from CryoSat-2 in SAR mode and provided via the RADS database are compared with the same parameters derived from the CryoSat-2 SAR Data to estimate possible biases and trends between SAR mode and LRM mode and tune-up the SAR re-tracking scheme. Special attention will be paid to spot trends between SAR and PLRM with respect the orbital

  4. Isolation by sugar flotation has no direct effect on the hatching success of zooplankton resting eggs

    Directory of Open Access Journals (Sweden)

    Dunja Lukic

    2016-03-01

    Full Text Available Zooplankton in temporary waters produces resting stages to survive recurrent dry periods. Branchiopod crustaceans (i.e., cladocerans, large branchiopods overcome these periods in the form of resting eggs buried in the sediment. Examining the diversity in the resting egg banks allows for a more accurate estimation of biodiversity of aquatic ecosystems than looking only at the active communities. The isolation of resting eggs from the sediment may be achieved by the sugar flotation method, which usually results in higher density and diversity than untreated samples (i.e., incubated in the sediment. We tested the effect of sugar isolation and centrifugation on the hatching success of resting eggs already isolated from sediment in order to reveal any direct effects on hatching success. We used four different branchiopod species, Daphnia magna, Moina brachiata, Branchinecta orientalis, and Triops cancriformis. Although we hypothesised that osmotic stress caused by sugar and centrifuging influence the hatching success either positively (e.g., faster activation as a response to osmotic changes or negatively (destroyed by centrifugation, we found no significant difference either in the timing or rate of hatching between centrifuged and non-centrifuged eggs. Once the eggs are exposed to light and/or oxygen availability by being removed from the sediment, the centrifugation process does not have any additional effect on their hatching. Regardless of treatment, we found a significant difference in the hatching timing in the two major groups, with large branchiopods hatching earlier than cladocerans. We found that the sugar flotation method itself does not influence the hatching fraction of branchiopod resting eggs (implying no adverse effect on their viability and its success in enhancing hatching can be attributed to its efficiency in removing eggs from the sediment.

  5. Zooplankton Linkages between Rivers and Great Lakes: Case Study from the St. Louis River

    Science.gov (United States)

    In this case study, we characterized the spatial and seasonal distribution and abundance of zooplankton within the hydrologically complex drowned river mouth of the St. Louis River, the second largest tributary to Lake Superior and an important fish nursery. We hypothesize that z...

  6. The role of subtropical zooplankton as grazers of phytoplankton under different predation levels

    NARCIS (Netherlands)

    Lacerot, G.; Kruk, C.; Lurling, M.; Scheffer, M.

    2013-01-01

    1.Large zooplankton such as Daphnia play a fundamental role as consumers of phytoplankton in temperate lakes. These organisms are scarce in subtropical lakes where smaller cladocerans or copepods take this niche. However, such smaller grazers appear to be less able to exert an effective top-down con

  7. Isotopic fractionation and trophic position of zooplankton species in the Upper Paraná River floodplain.

    Science.gov (United States)

    Santana, A R A; Benedito, E; Ducatti, C; Lansac-Tôha, F A

    2011-02-01

    This study aimed to evaluate the isotopic fractionation and trophic position of three zooplankton species (Notodiaptomus amazonicus, Moina minuta and Bosmina hagmanni) in the Upper Paraná River floodplain. We predict that phytoplankton is the main food resource used by these species. Three zooplankton samples and three phytoplankton samples were taken from each sampling site, with three to four samples collected for each species. The number of individuals for samples varied according to the body size: from 100 to 130 individuals for Notodiaptomus amazonicus; 150 to 200 for Moina minuta; and from 250 to 300 for Bosmina hagmanni. The isotopic values for δ13C and δ15N were determined using mass spectrophotometer. The isotopic fractionation of 13C was performed according to the relationship Δ = δ13C zooplankton - δ13C phytoplankton. To determine the possible trophic position of these species, we used the expression TL = (δ15N zooplankton - δ15N phytoplankton)/Δ+ 1. The species showed high variation in isotopic fractionation and in trophic position in the different environments. We verified that the species use other food resources in addition to phytoplankton. The elucidation and understanding of the trophic position of the organisms based on stable isotopic analysis offers complementary information to traditional techniques. This analysis helps explain the flow of matter and energy in the food chain of floodplain aquatic environments as well as trace the trophic relationships involved in the ecological roles and strategies of distinct species. PMID:21437401

  8. The role of subtropical zooplankton as grazers of phytoplankton under different predation levels

    NARCIS (Netherlands)

    Lacerot, G.; Kruk, C.; Lürling, M.; Scheffer, M.

    2013-01-01

    1. Large zooplankton such as Daphnia play a fundamental role as consumers of phytoplankton in temperate lakes. These organisms are scarce in subtropical lakes where smaller cladocerans or copepods take this niche. However, such smaller grazers appear to be less able to exert an effective top–down co

  9. Correlations between zooplankton assemblages and environmental factors in the downtown rivers of Shanghai, China

    Science.gov (United States)

    Yu, Na; Li, Erchao; Feng, Dexiang; Xiao, Baicai; Wei, Chaoqun; Zhang, Meiling; Chen, Liqiao

    2014-11-01

    Most urban rivers play an important role in urban flood control and drainage in China, but pollution is fast becoming an issue of greater importance in water management. In this study, 63 zooplankton species were recorded in four downtown rivers in Shanghai between November 2007 and October 2008. Of these, 44 species belonged to the Rotifera, 13 to Cladocera, and six to Copepoda. The three most frequently occurring zooplankton ( Brachionus calyciflorus, Microcyclops leuckarti, and Asplanchna priodonta) accounted for 80.00%, 76.84%, and 53.68%, respectively. Rotifera were found to be dominant, comprising 86.26% of total zooplankton, while cladoceran and copepod abundance amounted to 5.08% and 8.67%, respectively. Water temperature, salinity, electrical conductivity, and total nitrogen were of the greatest significance in the occurrence of zooplankton. Two species ( Schmackeria forbesi and Lepadella ovalis) were notably more sensitive to environmental factors such as salinity and electrical conductivity than other species. The population size and community were inversely correlated with the increasing nutrient levels of the four rivers, suggesting that the water quality of the four rivers had been gradually recovering from a severe eutrophic state and that water conditions of the rivers had been gradually improved.

  10. First study on the zooplankton of the Kerid (Kerið Crater Lake, Iceland

    Directory of Open Access Journals (Sweden)

    Vesela Evtimova

    2014-04-01

    Full Text Available We studied the qualitative composition of zooplankton of the Kerid Crater Lake. We found 10 taxa from which five rotifers and two lower crustaceans. Three of the recorded species are new to the freshwater fauna of Iceland: the rotifer species Keratella cf. americana Carlin, 1943 and Colurella sulcata (Stenroos, 1898, and the crustacean harpacticoid Bryocamptus (Bryocamptus minutus (Claus, 1863.

  11. Patchy zooplankton grazing and high energy conversion efficiency: ecological implications of sandeel behavior and strategy

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Christensen, Asbjørn; Rindorf, Anna

    2013-01-01

    of prey. Here we studied zooplankton consumption and energy conversion efficiency of lesser sandeel (Ammodytes marinus) in the central North Sea, using stomach data, length and weight-at-age data, bioenergetics, and hydrodynamic modeling. The results suggested: (i) Lesser sandeel in the Dogger area depend...... sandeel densities and growth rates per area than larger habitats...

  12. Vertical distribution of zooplankton: density dependence and evidence for an ideal free distribution with costs

    Directory of Open Access Journals (Sweden)

    Lampert Winfried

    2005-04-01

    Full Text Available Abstract Background In lakes with a deep-water algal maximum, herbivorous zooplankton are faced with a trade-off between high temperature but low food availability in the surface layers and low temperature but sufficient food in deep layers. It has been suggested that zooplankton (Daphnia faced with this trade-off distribute vertically according to an "Ideal Free Distribution (IFD with Costs". An experiment has been designed to test the density (competition dependence of the vertical distribution as this is a basic assumption of IFD theory. Results Experiments were performed in large, indoor mesocosms (Plankton Towers with a temperature gradient of 10°C and a deep-water algal maximum established below the thermocline. As expected, Daphnia aggregated at the interface between the two different habitats when their density was low. The distribution spread asymmetrically towards the algal maximum when the density increased until 80 % of the population dwelled in the cool, food-rich layers at high densities. Small individuals stayed higher in the water column than large ones, which conformed with the model for unequal competitors. Conclusion The Daphnia distribution mimics the predictions of an IFD with costs model. This concept is useful for the analysis of zooplankton distributions under a large suite of environmental conditions shaping habitat suitability. Fish predation causing diel vertical migrations can be incorporated as additional costs. This is important as the vertical location of grazing zooplankton in a lake affects phytoplankton production and species composition, i.e. ecosystem function.

  13. Zooplankton standing stock assessment and fishery resources in the indian seas

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Sarupria, J.S.; Bhargava, R.M.S.

    .6 ml m sup(-3) (av. = 0.156 plus or minus 0.218 ml m sup(-3)) and 0.02 to 0.37 ml m sup(-3) (av. = 0.12 plus or minus 0.079 ml m sup(-3)) respectively. The general pattern of zooplankton distribution showed an increasing trend towards north...

  14. Trace metal dynamics in zooplankton from the Bay of Bengal during summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; DineshKumar, P.K.; Nair, M.; Muraleedharan, K.R.

    Trace metal (Fe, Co, Ni, Cu, Zn, Cd, and Pb) concentrations in zooplankton from the mixed layer were investigated at 8 coastal and 20 offshore stations in the western Bay of Bengal during the summer monsoon of 2003. The ecotoxicological importance...

  15. Epizoic acoelomorph flatworms impair zooplankton feeding by the scleractinian coral Galaxea fascicularis

    NARCIS (Netherlands)

    Wijgerde, T.H.M.; Schots, P.; Onselen, van E.; Karruppannan, E.W.; Verreth, J.A.J.; Osinga, R.

    2013-01-01

    Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of heterotrophic feeding. To quantify the effect of epizoic flatworms on zooplankton

  16. Zooplankton of the Black Sea and the Eastern Mediterranean: Similarities and dissimilarities

    Directory of Open Access Journals (Sweden)

    A.V. KOVALEV

    2012-12-01

    Full Text Available A synthesis of data on abundance and biomass of zooplankton in the Eastern Mediterranean (EMED and the Black Sea shows major differences in the composition and structure of pelagic communities in the two basins. Few Mediterranean planktonic animals have invaded and acclimatised in the Black Sea. The great bulk of Black Sea species is represented by coastal inhabitants that spread throughout the whole basin. This process has been called “neritization” of the Black Sea fauna. Peculiarities in zooplankton assemblages of the Black Sea have been further strengthened over the last few decades due to increasing eutrophication and the massive invasion of the ctenophore Mnemiopsis leidyi. The relative contribution of copepods, cladocerans, chaetognaths, and appendicularians to total zooplankton biomass has notably decreased , whereas gelatinous groups (mainly represented by Mnemiopsis and Aurelia aurita contributed up to 99% of total wet weight in 1995 in the Black Sea.The basic features of planktonic fauna in the Black Sea are mainly due do the geo-morphological characters of the basin and the limited exchanges with the EMED, that are confined to the surface-subsurface layers in the Dardanelles and Bosphorus Straits. However, the dramatic changes that recently occurred in the structure of zooplankton assemblages seem to have been caused by heavy anthropogenic impact on the pelagic system.

  17. Zooplankton feeding ecology and the experimental acidification of Little Rock Lake

    International Nuclear Information System (INIS)

    There is considerable variety in both the selective behavior of suspension feeders and the quality of food available to them. The author reviews this variability and incorporate it in a simple model of particle selection that quantifies the consequences of selective feeding under various feeding conditions. To evaluate the concept that selective feeding enhances fitness, the author tests the hypothesis than an herbivorous zooplankton selects food items that best support its reproduction. Investigations of zooplankton herbivory in experimentally acidified Little Rock Lake indicate that acidification from pH 6.2 to pH 5.2 has not directly impaired feeding rates, while effects on selective feeding behavior are evident. Assessment of the effects of lake acidification on large predatory zooplankton indicate that Chaoborus spp. and water mite populations remain as yet unaffected, while Epischura lacustris and Leptodora kindtii have both declined in the acidified basin. Methodological tests show that preservation of labelled zooplankton by rapid freezing on dry ice minimizes loss of 14C and 32P. 14C retention approximates 100%, while 32P retention is more variable

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Annual cycle of zooplankton abundance and species composition in Izmit Bay (the northeastern Marmara Sea)

    Science.gov (United States)

    Isinibilir, Melek; Kideys, Ahmet E.; Tarkan, Ahmet N.; Yilmaz, I. Noyan

    2008-07-01

    The monthly abundance, biomass and taxonomic composition of zooplankton of Izmit Bay (the northeastern Marmara Sea) were studied from October 2001 to September 2002. Most species within the zooplankton community displayed a clear pattern of succession throughout the year. Generally copepods and cladocerans were the most abundant groups, while the contribution of meroplankton increased at inner-most stations and dominated the zooplankton. Both species number ( S) and diversity ( H') were positively influenced by the increase in salinity of upper layers ( r = 0.30 and r = 0.31, p < 0.001, respectively), while chlorophyll a was negatively affected ( r = -0.36, p < 0.001). Even though Noctiluca scintillans had a significant seasonality ( F11,120 = 8.45, p < 0.001, ANOVA), abundance was not related to fluctuations in temperature and only chlorophyll a was adversely correlated ( r = -0.35, p < 0.001). In general, there are some minor differences in zooplankton assemblages of upper and lower layers. A comparison of the species composition and abundance of Izmit Bay with other Black Sea bays reveals a high similarity between them.

  1. 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.

    the major component (greater than 80%) of zooplankton throughout the year. Of the proximate principals, protein formed the major component. Overall mean values, calculated as percentages of dry weight were 16.65 protein, 4.33 carbohydrate, 2.51 lipid and 23...

  2. 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.

    the traditional fishing grounds of Kerala Coast. Average biomass values ranged from 45-95 ml 100/m sup(-3). Increase in zooplankton at night was discernible at most of the stations and the highest biomass noticed was 131 ml 100/m sup(-3). Copepods formed the most...

  3. Zooplankton, fish communities and the role of planktivory in nine Ethiopian lakes

    NARCIS (Netherlands)

    Vijverberg, J.; Dejen, E.; Getahun, A.; Nagelkerke, L.A.J.

    2014-01-01

    Fish and zooplankton populations of nine Ethiopian freshwater lakes were quantitatively sampled along a North–South gradient. Differences in altitude and latitude resulted in a temperature gradient from North to South. We tested three hypotheses: (1) the degree of zooplanktivory decreases with water

  4. Tracking seasonal changes in North Sea zooplankton trophic dynamics using stable isotopes

    NARCIS (Netherlands)

    Kürten, B.; Painting, S.J.; Struck, U.; Polunin, N.V.C.; Middelburg, J.J.

    2013-01-01

    Trophodynamics of meso-zooplankton in the North Sea (NS) were assessed at a site in the southern NS, and at a shallow and a deep site in the central NS. Offshore and neritic species from different ecological niches, including Calanus spp., Temora spp. and Sagitta spp., were collected during seven cr

  5. Predation on the Invasive Copepod, Pseudodiaptomus forbesi, and Native Zooplankton in the Lower Columbia River: An Experimental Approach to Quantify Differences in Prey-Specific Feeding Rates.

    Directory of Open Access Journals (Sweden)

    Jesse B Adams

    Full Text Available Invasive planktonic crustaceans have become a prominent feature of aquatic communities worldwide, yet their effects on food webs are not well known. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now dominates the late-summer zooplankton community, but its use by native aquatic predators is unknown. We investigated whether three species of planktivorous fishes (chinook salmon, three-spined stickleback, and northern pikeminnow and one species of mysid exhibited higher feeding rates on native copepods and cladocerans relative to P. forbesi by conducting `single-prey' feeding experiments and, additionally, examined selectivity for prey types with `two-prey' feeding experiments. In single-prey experiments individual predator species showed no difference in feeding rates on native cyclopoid copepods (Cyclopidae spp. relative to invasive P. forbesi, though wild-collected predators exhibited higher feeding rates on cyclopoids when considered in aggregate. In two-prey experiments, chinook salmon and northern pikeminnow both strongly selected native cladocerans (Daphnia retrocurva over P. forbesi, and moreover, northern pikeminnow selected native Cyclopidae spp. over P. forbesi. On the other hand, in two-prey experiments, chinook salmon, three-spined stickleback and mysids were non- selective with respect to feeding on native cyclopoid copepods versus P. forbesi. Our results indicate that all four native predators in the Columbia River Estuary can consume the invasive copepod, P. forbesi, but that some predators select for native zooplankton over P. forbesi, most likely due to one (or both of two possible underlying casual mechanisms: 1 differential taxon-specific prey motility and escape responses (calanoids > cyclopoids > daphnids or 2 the invasive status of the zooplankton prey resulting in naivety, and thus lower feeding rates, of native predators feeding on invasive prey.

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

    Science.gov (United States)

    Okogwu, Okechukwu I

    2010-03-01

    Ehoma Lake is among the important breeding sites of the major fishes in the Mid-Cross River, Nigeria. The juveniles of these fishes are solely dependent on zooplankton, which has not been studied previously. I studied monthly the lake's physico-chemical variables and zooplankton composition in three stations (littoral, sub-littoral and pelagic) from March 2005 to August 2006. Sixty-seven zooplankton species (42 rotifers, 19 cladocerans and 6 copepods) were identified. Daphnia obtusa Kurz, Keratella valga Ehrenberg, Keratella ticinensis Callerrio, Keratella hiemalis Carlin, Brachionus dimidiatus Bryce and Lecane candida Hauer and Murray are new records for Nigeria The dominant zooplankters were Diaphanosoma excisum Kurz and Moina micrura Kurz. There was an inverse relationship between species richness and abundance. Richness was highest in the dry season while peak zooplankton abundance was recorded in the rainy season. Zooplankton abundance and species richness decreased progressively from the littoral to the pelagic station while the Shannon-Weaver diversity index varied from 0.68 to 1.28 without a clear seasonal trend. There is a succession pattern: rotifers that are dominant in the dry season are replaced by cladocerans in the rainy season. This succession was greatly influenced by seasonal flooding of the lake. As no previous information on the zooplankton of the lake is available, this study provides baseline data on the lake's zooplankton. PMID:20411715

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

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

  8. Delineation of estuarine fronts in the German Bight using airborne laser-induced water Raman backscatter and fluorescence of water column constituents

    Science.gov (United States)

    Hoge, F. E.; Swift, R. N.

    1982-01-01

    The acquisition and application of airborne laser induced emission spectra from German Bight water during the 1979 MARSEN experiment is detailed for the synoptic location of estuarine fronts. The NASA Airborne Oceanographic Lidar (AOL) was operated in the fluorosensing mode. A nitrogen laser transmitter at 337.1 nm was used to stimulate the water column to obtain Gelbstoff or organic material fluorescence spectra together with water Raman backscatter. Maps showing the location and relative strength of estuarine fronts are presented. The distribution of the fronts indicates that mixing within the German Bight takes place across a relatively large area. Reasonable agreement between the patterns observed by the AOL and published results are obtained. The limitations and constraints of this technique are indicated and improvements to the AOL fluorosensor are discussed with respect to future ocean mapping applications.

  9. The Lake Ontario zooplankton community before (1987-1991) and after (2001-2005) invasion-induced ecosystem change

    Science.gov (United States)

    Stewart, T.J.; Johannsson, O.E.; Holeck, K.; Sprules, W.G.; O'Gorman, R.

    2010-01-01

    We assessed changes in Lake Ontario zooplankton biomass, production, and community composition before (1987–1991) and after (2001–2005) invasion-induced ecosystem changes. The ecosystem changes were associated with establishment of invasive dreissenid mussels and invasive predatory cladocerans (Bythotrephes and Cercopagis). Whole-lake total epilimnetic plus metalimnetic zooplankton production declined by approximately half from 42.45 (g dry wt∙m−2∙ year−1) during 1987–1991 to 21.91 (g dry wt∙m−2∙ year−1) in 2003 and averaged 21.01 (g dry wt∙m−2∙ year−1) during 2001–2005. Analysis of two independent data sets indicates that the mean biomass and biomass proportion of cyclopoid copepods declined while the same measures increased for the invasive predatory cladocerans. Changes in means and proportions of all other zooplankton groups were not consistent between the data sets. Cyclopoid copepod biomass and production declined by factors ranging from 3.6 to 5.7. Invasive predatory cladoceran biomass averaged from 5.0% to 8.0% of the total zooplankton biomass. The zooplankton community was otherwise resilient to the invasion-induced disruption as zooplankton species richness and diversity were unaffected. Zooplankton production was likely reduced by declines in primary productivity but may have declined further due to increased predation by alewives and invasive predatory cladocerans. Shifts in zooplankton community structure were consistent with increased predation pressure on cyclopoid copepods by alewives and invasive predatory cladocerans. Predicted declines in the proportion of small cladocerans were not evident. This study represents the first direct comparison of changes in Lake Ontario zooplankton production before and after the invasion-induced disruption and will be important to food web-scale investigations of invasion effects.

  10. Feeding ecology of mesopelagic zooplankton of the subtropical and subarctic North Pacific Ocean determined with fatty acid biomarkers

    Science.gov (United States)

    Wilson, S. E.; Steinberg, D. K.; Chu, F.-L. E.; Bishop, J. K. B.

    2010-10-01

    Mesopelagic zooplankton may meet their nutritional and metabolic requirements in a number of ways including consumption of sinking particles, carnivory, and vertical migration. How these feeding modes change with depth or location, however, is poorly known. We analyzed fatty acid (FA) profiles to characterize zooplankton diet and large particle (>51 μm) composition in the mesopelagic zone (base of euphotic zone -1000 m) at two contrasting time-series sites in the subarctic (station K2) and subtropical (station ALOHA) Pacific Ocean. Total FA concentration was 15.5 times higher in zooplankton tissue at K2, largely due to FA storage by seasonal vertical migrators such as Neocalanus and Eucalanus. FA biomarkers specific to herbivory implied a higher plant-derived food source at mesotrophic K2 than at oligotrophic ALOHA. Zooplankton FA biomarkers specific to dinoflagellates and diatoms indicated that diatoms, and to a lesser extent, dinoflagellates were important food sources at K2. At ALOHA, dinoflagellate FAs were more prominent. Bacteria-specific FA biomarkers in zooplankton tissue were used as an indicator of particle feeding, and peaks were recorded at depths where known particle feeders were present at ALOHA (e.g., ostracods at 100-300 m). In contrast, depth profiles of bacterial FA were relatively constant with depth at K2. Diatom, dinoflagellate, and bacterial biomarkers were found in similar proportions in both zooplankton and particles with depth at both locations, providing additional evidence that mesopelagic zooplankton consume sinking particles. Carnivory indices were higher and increased significantly with depth at ALOHA, and exhibited distinct peaks at K2, representing an increase in dependence on other zooplankton for food in deep waters. Our results indicate that feeding ecology changes with depth as well as by location. These changes in zooplankton feeding ecology from the surface through the mesopelagic zone, and between contrasting environments

  11. A global analysis of zooplankton in natural and artificial fresh waters

    Directory of Open Access Journals (Sweden)

    Faye L. Merrix-Jones

    2013-02-01

    Full Text Available Water-body size and location influence zooplankton diversity in freshwaters, but less is known about systematic variations in zooplankton community composition between natural and artificial waters on different continents. We used meta-analysis to assess how zooplankton in artificial water bodies across different biomes might differ from natural water bodies of similar size. Among 79 lakes, ponds and reservoirs (11 artificial and 68 natural, proximity to other water bodies apparently increased species richness in all lake types, probably reflecting dispersal. However, richness did not differ systematically between natural and artificial water bodies of comparable size. In contrast, community composition differed between artificial and natural waters after accounting for depth, productivity, longitude and conductivity, with models explaining up to 50% of the overall variance at genus level. Leptodiaptomus, Chydorus, Cyclops, Acanthocyclops, Skistodiaptomus, Epischura, Limnocalanus, Senecella, Heterocope, Arctodiaptomus and Aglaodiaptomus all occurred more frequently in natural waters, whilst Thermocyclops, Moina and Epischura occurred more frequently in artificial lakes. Rank-occurrence data revealed that Ceriodaphnia, Orthocyclops, Holopedium and Eucyclops were equitably distributed across water bodies of contrasting sizes, depths and climates. Other genera occurred under more specific conditions, typically where they had strong associations with natural lakes (e.g. Limnocalanus, Senecella, Heterocope, Arctodiaptomus and Aglaodiaptomus. These results are among the first to illustrate systematic differences in zooplankton composition between natural and artificial lakes at a global scale. Potential explanations require further evidence, but might include provision for niche specialists in natural lakes versus reduced heterogeneity, management or disturbance effects in artificial lakes; and effects of lake age, stability and habitat naturalness in

  12. Zooplankton distribution and behaviour in the Southern Ocean from surveys with a towed Optical Plankton Counter

    Science.gov (United States)

    Pollard, R. T.; Bathmann, U.; Dubischar, C.; Read, J. F.; Lucas, M.

    Spatial distributions of zooplankton with lengths between about 500 μm and 8 mm are described from surveys in the vicinity of the Antarctic Polar Front in austral summer 1995/6 using an Optical Plankton Counter mounted on a towed profiling SeaSoar. The distributions, split into several logarithmically spaced size classes, are compared and related to the physical environment south of the Polar Front in the Antarctic Zone and within the Polar Frontal Zone. They also are compared with phytoplankton distributions determined from surface chlorophyll data. Both phytoplankton and zooplankton carbon densities are low in the Antarctic Zone (2-3 g C m -2), but rise to larger values in the Polar Frontal Zone (5-7 g C m -2 for zooplankton and a maximum of 6 g C m -2 at fronts for phytoplankton). Calibration of OPC derived zooplankton biovolume to carbon was achieved by comparison with dry weights from multinet samples deployed in conjunction with CTD casts. The net data showed that over 98% of zooplankton counts were copepods. Diel behaviour also was examined. Only larger copepods (over 2 mm long) displayed significant diel migration, and then only 10-20% of the standing stock; the majority remained deeper than about 100 m and their distribution patterns suggest that they may be retained aside from the main frontal jets by ageostrophic circulations associated with the front. Copepods shorter than 2 mm rose from depth over the month-long survey to become concentrated in the surface layer (the top 70-100 m). The largest copepods that could be resolved, with lengths of about 4-8 mm (possibly Rhincalanus gigas), displayed unexpected behaviour in tending to migrate to the top 0-10 m by day, descending to 40-50 m each night.

  13. Zooplankton diversity and physico-chemical conditions in three perennial ponds of Virudhunagar district, Tamilnadu.

    Science.gov (United States)

    Rajagopal, T; Thangamani, A; Sevarkodiyone, S P; Sekar, M; Archunan, G

    2010-05-01

    Plankton diversity and physico-chemical parameters are an important criterion for evaluating the suitability of water for irrigation and drinking purposes. In this study we tried to assess the zooplankton species richness, diversity and evenness and to predict the state of three perennial ponds according to physico-chemical parameters. A total of 47 taxa were recorded: 24 rotifers, 9 copepods, 8 cladocerans, 4 ostracods and 2 protozoans. More number of zooplankton species were recorded in Chinnapperkovil pond (47 species) followed by Nallanchettipatti (39 species) and Kadabamkulam pond (24 species). Among the rotifers, Branchionus sp. is abundant. Diaphanosoma sp. predominant among the cladocerans. Among copepods, numerical superiority was found in the case of Mesocyclopes sp. Cypris sp. repeated abundance among ostracoda. Present study revealed that zooplankton species richness (R1 and R2) was comparatively higher (R1: 4.39; R2: 2.13) in Chinnapperkovil pond. The species diversity was higher in the Chinnapperkovil pond (H': 2.53; N1: 15.05; N2: 15.75) as compared to other ponds. The water samples were analyzed for temperature, pH, electrical conductivity alkalinity salinity, phosphate, hardness, dissolved oxygen and biological oxygen demand. Higher value of physico-chemical parameters and zooplankton diversity were recorded in Chinnapperkovil pond as compared to other ponds. The zooplankton population shows positive significant correlation with physico-chemical parameters like, temperature, alkalinity phosphate, hardness and biological oxygen demand, whereas negatively correlated with rainfall and salinity. The study revealed that the presence of certain species like, Monostyla sp., Keratella sp., Lapadella sp., Leydigia sp., Moinodaphnia sp., Diaptomus sp., Diaphanosoma sp., Mesocyclopes sp., Cypris sp. and Brachionus sp. is considered to be biological indicator for eutrophication.

  14. 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.

  15. Tidal exchange of zooplankton between Lough Hyne and the adjacent coast

    Science.gov (United States)

    Rawlinson, K. A.; Davenport, J.; Barnes, D. K. A.

    2005-01-01

    Plankton samples collected in November 2002, February, May and August 2003 were used to examine seasonal variation in tidal exchange of zooplankton biomass, abundance and species composition between Lough Hyne Marine Nature Reserve and the adjacent Atlantic coast. Micro- to mesozooplankton were collected by pump over 24-h sampling periods during spring and neap tides from the narrow channel connecting the semi-enclosed water body to the Atlantic. Sample biomass (dry weight) and total zooplankton abundance peaked in the summer and were lowest in winter, showing a positive relationship with temperature. Zooplankton biomass, total abundance and numbers of holo- and meroplankton revealed import during some diel cycles and export in others. However, the tidal import of these planktonic components was generally dominant, especially during May. The greatest import of numbers of holoplankters and meroplanktonic larvae occurred during May and August, respectively. There was no significant variation in sample biomass between periods of light and dark, but some variation in zooplankton abundance could be explained by this diel periodicity. Significant differences in sample assemblage composition between flood and ebb tide samples were always observed, except during winter neap tides. There was a net import of the copepods Temora longicornis and Oithona helgolandica and the larval stages of Mytilus edulis during spring and summer. Proceraea cornuta and Capitellid trochophores were imported during winter, and a hydrozoan of the genus Obelia during the spring spring tides. Seasonal export from the lough was shown by Pseudopolydora pulchra larvae (autumn and spring), Serpulid trochophores (autumn) and veligers of the bivalve Anomia ephippium (summer). It is suggested that the direction of tidal exchange of meroplanktonic taxa is related to the distribution of the adult populations. Copepod naupliar stages dominated the assemblages except during May spring tides when the copepod

  16. Zooplankton from a polluted river, Mula (India, with record of Brachionus rubens (Ehrenberg, 1838 epizoic on Moina macrocopa (Straus, 1820

    Directory of Open Access Journals (Sweden)

    Vanjare, A.I.

    2010-06-01

    Full Text Available Rotifera and Cladocera are free living zooplankton elements known to dominate freshwater habitats. Few rotifersare known to be parasitic and epizoic living in association with other organisms. Zooplankton from the polluted river Mula, Pune,Maharashtra was sampled from January to November 2009. Eighteen rotifers and ten cladocerans were recorded during the study.Samples revealed rotifer Brachionus rubens (Ehrenberg, 1838 epizoic on cladoceran Moina macrocopa (Straus, 1820, theoccurrence of which coincided with lower dissolved oxygen (DO content. The rotifers Asplanchnopus multiceps (Schrank,1793, Lacinularia elliptica (Shephard, 1897 and the cladoceran Kurzia longirostris (Daday, 1898 are new records to Maharashtrastate. The present study was an attempt to monitor a polluted habitat for zooplankton fauna. Detailed studies onorganically polluted eutrophic habitats could add new insights into zooplankton diversity and behaviour.

  17. 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.

  18. Ecological factors affecting the distribution of the zooplankton community in the Tigris River at Baghdad region, Iraq

    OpenAIRE

    Shayma Abdulwahab; Adel M. Rabee

    2015-01-01

    Biodiversity of zooplankton in the Tigris River running in Baghdad City, central Iraq, was investigated. Fourteen physical and chemical parameters, were analyzed, these parameters include water and air temperature, pH, EC, turbidity, TDS, DO, BOD5, total hardness, Ca+2, Mg+2, chloride, nitrate and reactive phosphate. Most of these values were within of the Iraqi and international standard limits. In all, 106 taxonomy units of zooplankton were identified, including 65 taxa belonging to rotifer...

  19. The Uday river’s littoral zooplankton in the region of the national nature park «Pyriatynskiy»

    OpenAIRE

    V. N. Trokhymets; M. V. Sydorenko; A. V. Podobaylo

    2011-01-01

    The ecological-faunistic analysis of the littoral zooplankton of the middle part of the Uday River has been performed for the first time. The research was conducted to confirm a reason to create the National Nature Park «Pyriatynskiy» in this region. The species diversity of the littoral zooplankton obtained from six scientific stations on the Uday River was established. The specific features of the zooplankton’s distribution in biotopes in summer days were revealed. The comparative descripti...

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

    Science.gov (United States)

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

    2013-04-01

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

  1. 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...

  2. 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.

  3. 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, ppump.

  4. Comparative studies on zooplankton community between the sea surface microlayer and the subsurface microlayer in Daya Bay, China

    Institute of Scientific and Technical Information of China (English)

    YANG Yufeng

    2005-01-01

    Characteristics of the zooplankton community inhabiting the sea surface microlayer (SM) and the sub-surface microlayer (SSM) are compared at six sampling stations in Daya Bay, near Shenzhen City of China during 2 cruises in 1999. This is the first study on zooplankton community in the SM in China. Results show that protozoans and nauplii are the most dominant components, accounting for 80.71% (SM) and 89.15% (SSM) of the total zooplankton in the average abundance, respectively. The densities of copepods (adult + copepodid) are higher in the SSM than in the SM. The size-frequency distributions indicate that the frequency of micro-zooplankton (<0.2mm) is higher in the SM (0.8235, n =290) than in the SSM (0.6768, n = 306). Enrichment phenomenon of zooplankton is detected in the SM at the sampling stations excluding two stations near nuclear power plants (NPP). The enrichment factor is from 1. 516to 3. 364 with the average value of 2. 267. The SM zooplankton community structure revealed in the present study is quite different from previous investigations in the Bay. Typical sea water characteristics such as turbidity, biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and chlorophyll a (Chl-a) indicate that the water quality is poorer in the SM than in the SSM.

  5. Influence of season, location, and feeding strategy on bioaccumulation of halogenated organic contaminants in Arctic marine zooplankton.

    Science.gov (United States)

    Hallanger, Ingeborg G; Ruus, Anders; Herzke, Dorte; Warner, Nicholas A; Evenset, Anita; Heimstad, Eldbjørg S; Gabrielsen, Geir W; Borgå, Katrine

    2011-01-01

    The influence of season, location, feeding strategy, and trophic position on concentration, compositional pattern, and bioaccumulation factors (BAFs) of halogenated organic contaminants (HOCs; polychlorinated biphenyls, chlorinated pesticides, and brominated flame retardants) was investigated within an Arctic zooplankton food web. Water (dissolved fraction) and seven Arctic marine pelagic zooplankton species (including herbivores, omnivores, and predators) were sampled in May, July, and October 2007 at two stations in Kongsfjorden, Svalbard, Norway. The HOC concentrations in both water and zooplankton generally decreased from May to October. The HOC concentrations and patterns among zooplankton species were explained by their feeding strategies, roughly categorized as herbivores, omnivores, and predators, and not stable isotope-derived trophic position. Field-derived BAFs varied greatly, with higher BAFs in May compared with July and October. Furthermore, BAFs differed among the species according to their feeding strategies. The relationship between BAFs from the different seasons and K(OW) (octanol:water partitioning coefficient) showed comparable intercepts and different slopes between May and October, with all relationships diverging from the assumed 1:1 relationship between BAF and K(OW). Differences in HOC concentrations and BAFs from herbivores to predators showed that biomagnification occurred in zooplankton. The results suggest that concentrations and patterns of HOCs in zooplankton species are influenced not only by equilibrium partitioning with water but also by feeding strategy. PMID:20853452

  6. Arsenic concentrations in some coexisting marine organisms from Newfoundland and Labrador. [Shrimp, Zooplankton, Fish

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, V.S.

    1976-06-01

    Inorganic arsenic concentrations in sea water and mud, and total arsenic concentrations, in bodies of shrimp, zooplankton, and fish from northern Newfoundland and southern Labrador were measured. There was a positive relationship between concentration and carapace length in Pandalus borealis and P. montagui and a negative relationship in Eualus macilentus. There was no relationship between concentrations in shrimp eggs and carapace length. Arsenic concentrations in zooplankton and fish muscle were relatively low compared with the shrimp species; amphipods contained more arsenic than copepods or euphausiids, and American plaice (Hippoglossoides platessoides) more than redfish (Sebastes marinus), turbot (Reinhardtius hippoglossoides), and Atlantic cod (Gadus morhua). There was no evidence of increasing arsenic concentrations through successively higher levels of the food chain.

  7. The Zooplankton Fauna of Kemer Dam Lake (Aydın-Turkey

    Directory of Open Access Journals (Sweden)

    Aslı TUNA

    2016-08-01

    Full Text Available In the present study the zooplankton fauna of Kemer Dam Lake (Aydın was investigated during December 2004 and November 2005. Total 24 taxa (14 taxa from rotifers, 8 taxa from cladocerans, and 2 taxa from copepods were identified in Kemer Dam Lake. Ascomorpha ovalis, Asplanchna priodonta, Collotheca pelagica, Hexarthra fennica, Keratella cochlearis, Keratella quadrata, Lecane luna, Lecane lunaris, Notholca squamula, Plationus patulus, Polyarthra dolichoptera, Polyarthra vulgaris, Synchaeta oblonga, Trichocerca similis from the rotifer species; Alona quadrangularis, Bosmina longirostris, Ceriodaphnia quadrangula, Coronatella rectangula, Daphnia cucullata, Diaphanosoma lacustris, Disparalona rostrata, Moina micrura from the Cladocera species; and Acanthodiaptomus denticornis, Cyclops abyssorum from the Copepoda species are new records for Kemer Dam lake. The average total zooplankton abundance ranged between 8706 - 124869 ind/m3 (December and April, respectively.

  8. 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

    and widely overlapping size ranges prevented a detailed analysis of the fine scale vertical distribution and the horizontal variability of abundance for distinct species. These results are used to discuss the limitations of the OPC for rapid and continuous surveying of spatial distribution and abundance......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...... in order to identify main species in the in situ size frequency distributions obtained by the submersible version of the OPC. Differences in the particle concentration between shallow and deep water layers were clearly resolved by the submersible OPC, but the high diversity of the zooplankton community...

  9. Method for the in situ study of pollutant effects on natural zooplankton communities

    International Nuclear Information System (INIS)

    A new method was developed and tested for the in situ study of pollutant effects on zooplankton communities in large lakes which does not suffer the limitations of large enclosures. In each of five experiments conducted in northern Green Bay, Lake Michigan, two to four samples of lower epilimnion water for each of four levels of added pollutant (Cd) plus controls were incubated in situ in opaque, polyethylene carboys (2 to 5 gallon size) for 4 to 15 days. In each experiment 2 to 4 additional samples, which were not incubated, were also taken. This new method appears to overcome some of the limitations imposed by the use of large, transparent bags or open-top tubes in large lakes for studies of pollutant effects on zooplankton, at least for short- to intermediate-term effects

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

    Science.gov (United States)

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

    2011-12-01

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

  11. Zooplankton diversity and its variation in the Northern Yellow Sea in the autumn and winter of 1959, 1982 and 2009%北黄海秋、冬季浮游动物多样性及年间变化

    Institute of Scientific and Technical Information of China (English)

    杨青; 王真良; 樊景凤; 邵魁双; 李宏俊

    2012-01-01

    classifications were analyzed using CLUSTER analysis and the SIMPROF test (Primer 6.0 software). Three zooplankton communities were distinguished as: the NYS High Salinity Water Community, the NYS Mixed Water Community and the NYS Coastal Water Community.In the autumn and winter of 2009 , the warm water species Doliolum denticulatum and Sagitta enjlata were observed in the NYS. The average abundance of D. denticulatum was 81. 00 ind/m3 and 0. 06 ind/m3 in autumn and winter, respectively. The frequency of occurrence was 57. 1% in autumn and 7. 1% in winter. The average abundance of S. enjlata was 0. 24 ind/m3 and 0. 37 ind/m3 in autumn and winter, respectively. The frequency of occurrence was 14. 3% in autumn and 50.0% in winter. Notably, in autumn of 2009, D. denticulatum became one of the dominant zooplankton species in the NYS. In the same season during 1959, the northward distribution limit of these warm water species did not reach the NYS. The northward expansion of these warm water species might reveal the reinforcement of the Yellow Sea Warm Current (YSWC ) from the impacts of climate change. Calanus sinicus and S. crassa were the main warm-temperate species and dominated the zooplankton in both seasons measured. In autumn and winter of 2009 , the abundance of both C. sinicus and S. crassa was higher than those in the same period of 1959. In autumn, the average abundance of C. sinicus in 2009 was 3.7 times that in 1959 and 5.4 times that in 1982. The maximum abundance of C. sinicus in 2009 was 3. 5 times that in 1959 and 1. 7 times that in 1982. The abundance of the main warm-temperate species has increased significantly in the NYS over the past 50 years. We hypothesize that climate change is responsible for the northward expansion of warm water species ( D. denticulatum and S. enflata) and the increase in abundance of the main warm-temperate species ( C. sinicus and S. crassa) in the NYS. The response model of zooplankton to climate change in the NYS (warm-temperate sea

  12. The combined influence of two agricultural contaminants on natural communities of phytoplankton and zooplankton.

    Science.gov (United States)

    Baker, Leanne F; Mudge, Joseph F; Thompson, Dean G; Houlahan, Jeff E; Kidd, Karen A

    2016-07-01

    Concentrations of glyphosate observed in the environment are generally lower than those found to exert toxicity on aquatic organisms in the laboratory. Toxicity is often tested in the absence of other expected co-occurring contaminants. By examining changes in the phytoplankton and zooplankton communities of shallow, partitioned wetlands over a 5 month period, we assessed the potential for direct and indirect effects of the glyphosate-based herbicide, Roundup WeatherMax(©) applied at the maximum label rate, both in isolation and in a mixture with nutrients (from fertilizers). The co-application of herbicide and nutrients resulted in an immediate but transient decline in dietary quality of phytoplankton (8.3 % decline in edible carbon content/L) and zooplankton community similarity (27 % decline in similarity and loss of three taxa), whereas these effects were not evident in wetlands treated only with the herbicide. Thus, even at a worst-case exposure, this herbicide in isolation, did not produce the acutely toxic effects on plankton communities suggested by laboratory or mesocosm studies. Indirect effects of the herbicide-nutrient mixture were evident in mid-summer, when glyphosate residues were no longer detectable in surface water. Zooplankton abundance tripled, and zooplankton taxa richness increased by an average of four taxa in the herbicide and nutrient treated wetlands. The lack of significant toxicity of Roundup WeatherMax alone, as well as the observation of delayed interactive or indirect effects of the mixture of herbicide and nutrients attest to the value of manipulative field experiments as part of a comprehensive, tiered approach to risk assessments in ecotoxicology. PMID:27112456

  13. 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

  14. Hydroxide stabilization as a new tool for ballast disinfection: efficacy of treatment on zooplankton

    Science.gov (United States)

    Moffitt, Christine M.; Watten, Barnaby J.; Barenburg, Amber; Henquinet, Jeffrey

    2016-01-01

    Effective and economical tools are needed for treating ship ballast to meet new regulatory requirements designed to reduce the introduction of invasive aquatic species from ship traffic. We tested the efficacy of hydroxide stabilization as a ballast disinfection tool in replicated, sequential field trials on board the M/V Ranger III in waters of Lake Superior. Ballast water was introduced into each of four identical 1,320 L stainless steel tanks during a simulated ballasting operation. Two tanks were treated with NaOH to elevate the pH to 11.7 and the remaining two tanks were held as controls without pH alteration. After retention on board for 14–18 h, CO2-rich gas recovered from one of two diesel propulsion engines was sparged into tanks treated with NaOH for 2 h to force conversion of NaOH ultimately to sodium bicarbonate, thereby lowering pH to about 7.1. Prior to gas sparging, the engine exhaust was treated by a unique catalytic converter/wet scrubber process train to remove unwanted combustion byproducts and to provide cooling. The contents of each tank were then drained and filtered through 35-µm mesh plankton nets to collect all zooplankton. The composition and relative survival of zooplankton in each tank were evaluated by microscopy. Zooplankton populations were dominated by rotifers, but copepods and cladocerans were also observed. Hydroxide stabilization was 100% effective in killing all zooplankton present at the start of the tests. Our results suggest hydroxide stabilization has potential to be an effective and practical tool to disinfect ship ballast. Further, using CO2 released from the ship engine reduces emissions and the neutralized by product, sodium bicarbonate, can have beneficial impacts on the aquatic environment.

  15. Zooplankton variability and larval striped bass foraging: Evaluating potential match/mismatch regulation

    Science.gov (United States)

    Chick, J.H.; Van Den Avyle, M.J.

    1999-01-01

    We quantified temporal and spatial variability of zooplankton in three potential nursery sites (river, transition zone, lake) for larval striped bass (Morone saxatilis) in Lake Marion, South Carolina, during April and May 1993-1995. In two of three years, microzooplankton (rotifers and copepod nauplii) density was significantly greater in the lake site than in the river or transition zone. Macrozooplankton (>200 ??m) composition varied among the three sites in all years with adult copepods and cladocerans dominant at the lake, and juvenile Corbicula fluminea dominant at the river and transition zone. Laboratory feeding experiments, simulating both among-site (site treatments) and within-site (density treatments) variability, were conducted in 1995 to quantify the effects of the observed zooplankton variability on foraging success of larval striped bass. A greater proportion of larvae fed in the lake than in the river or transition-zone treatments across all density treatments: mean (x), 10x and 100x. Larvae also ingested significantly more dry mass of prey in the lake treatment in both the mean and 10x density treatments. Field zooplankton and laboratory feeding data suggest that both spatial and temporal variability of zooplankton influence larval striped bass foraging. Prey density levels that supported successful foraging in our feeding experiments occurred in the lake during late April and May in 1994 and 1995 but were never observed in the river or transition zone. Because the rivers flowing into Lake Marion are regulated, it may be possible to devise flow management schemes that facilitate larval transport to the lake and thereby increase the proportion of larvae matched to suitable prey resources.

  16. Influence of zooplankton stoichiometry on nutrient sedimentation in a lake system

    OpenAIRE

    Darchambeau, François; Thys, I.; Leporcq, B.; Hoffmann, L.; Descy, J.-P.

    2005-01-01

    We explored rates and stoichiometry (C: N: P ratios) of sinking particles in a temperate reservoir during a 2-yr period. Plankton was sampled weekly, and a sediment trap placed below the metalimnion collected sinking particles. There were no significant relationships between the stoichiometry of entrapped material and seston or zooplankton stoichiometry. However the differences in the entrapped C: P and N: P ratios between consecutive trap samplings were negatively correlated with the time va...

  17. 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.

  18. The role of zooplankton in the pelagic-benthic coupling of the Southern Ocean

    OpenAIRE

    Schnack-Schiel, Sigrid B.; Isla, Enrique

    2005-01-01

    [EN] Zooplankton contributes in different ways to pelagic-benthic coupling: Their faecal material is a major route of energy flow and the vertical migrations of many species as well as the production of pelagic larvae by benthic organisms represent different paths to link the two subsystems. Antarctic particle fluxes have been shown to be highly variable in size and composition within a given region and even at the same site from year to year. There are also differences throughout the water c...

  19. 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...

  20. Epizoic acoelomorph flatworms impair zooplankton feeding by the scleractinian coral Galaxea fascicularis

    OpenAIRE

    Wijgerde, T.H.M.; Schots, P.; Onselen, van, E.; Karruppannan, E.W.; Verreth, J.A.J.; Osinga, R.

    2013-01-01

    Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of heterotrophic feeding. To quantify the effect of epizoic flatworms on zooplankton feeding, we conducted video analyses of single polyps of Galaxea fascicularis (Linnaeus 1767) grazing on Artemia nauplii in the presence and absence of symbiotic flatworms. 18S DNA analysis reveale...

  1. Epizoic acoelomorph flatworms impair zooplankton feeding by the scleractinian coral Galaxea fascicularis

    OpenAIRE

    Tim Wijgerde; Pauke Schots; Eline Van Onselen; Max Janse; Eric Karruppannan; Johan A.J. Verreth; Ronald Osinga

    2012-01-01

    Summary Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of heterotrophic feeding. To quantify the effect of epizoic flatworms on zooplankton feeding, we conducted video analyses of single polyps of Galaxea fascicularis (Linnaeus 1767) grazing on Artemia nauplii in the presence and absence of symbiotic flatworms. 18S DNA analysis...

  2. 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.

  3. Zooplankton community occurrence in an area influenced by uranium mine, Caldas, MG, Brazil

    International Nuclear Information System (INIS)

    The Ore Treatment Unit (UTM), situated on the Pocos de Caldas - MG Plateau, is Brazil's first venture in uranium ore mining and chemical treatment and it belongs to Brazilian Nuclear Industries today. At UTM, radioactive effluents are generated due to the mine's acid drainage processes (MAD). Thus, due to the lack of scientific information with emphasis on Zooplankton Communities in areas impacted by uranium mine and MAD, the current study aimed to evaluate parameters such as electrical conductivity, pH, total phosphorus, total nitrogen, sulfate, fluoride, uranium, thorium, manganese, zinc and aluminum, as well as richness and density of the zooplankton organism's, all in samples from the Pit Mine. The electrical conductivity values observed were elevated (1976 to 2760 μS cm-1), while the pH values remained acidic (3.6 to 4.1). In respect to the SO4-2, elevated concentrations were observed (366.6 - 1832.0 mg L-1), as well as for F- (33.4 to 75.1 mg L-1). The U presented highest and lowest concentrations in Oct/08 and July/09, that is, 4.25 mg L-1 and 0.12 mg L-1, respectively. The Th concentrations remained constant (0.10 - 0.30 mg L-1). In respect to the Zooplankton Community low species richness and density were observed throughout the whole period. The low richness and density values of the zooplankton species can be related to the adverse environmental conditions, which are unfavorable to the development of this community: elevated values of electrical conductivity and acidic pH, both associated to the chemical composition of the effluent in natura. (author)

  4. Ingestion by Japanese Eel Anguilla japonica Larvae on Various Minute Zooplanktons

    OpenAIRE

    Wullur, Stenly; Yoshimatsu, Takao; Tanaka, Hideki; Ohtani, Masataka; Sakakura, Yoshitaka; Kim, Hee-Jin; Hagiwara, Atsushi

    2013-01-01

    We observed the feeding incidence of Japanese eel Anguilla japonica larvae of 6, 7, 8 and 14 days after hatching (DAH) using various minute zooplanktons such as rotifer (Proales similis, Synchaeta sp., Keratella sp., Brachionus rotundiformis, B. angularis) and nauplii of copepod Paracyclopina nana, and compared those results to slurry type diets (i.e., shark eggs for control) to evaluate the usability of these planktons as primary food source for the mass culture of eel larvae. Feeding incid...

  5. 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. PMID

  6. Trophic structure of zooplankton in the Fram Strait in spring and autumn 2003

    Science.gov (United States)

    Blachowiak-Samolyk, Katarzyna; Kwasniewski, Slawek; Dmoch, Katarzyna; Hop, Haakon; Falk-Petersen, Stig

    2007-11-01

    The trophic structure of zooplankton was investigated in Fram Strait (north western Svalbard) in spring and autumn of 2003. Depth-stratified zooplankton samples were collected at 12 stations on the shelf (˜200 m), across the shelf-slope (˜500 m) and over deep water (>750 m), using a Multiple Plankton Sampler equipped with 0.180-mm mesh size nets. Higher zooplankton abundance and estimated biomass were found in the shelf area. Abundance and biomass were two times higher in August, when sea-surface temperature was higher than in May. Herbivores dominated numerically in May, and omnivores in August, suggesting a seasonal sequence of domination by different trophic groups. Cirripedia nauplii and Fritillaria borealis prevailed in spring, whereas copepod nauplii and Calanus finmarchicus were numerically the most important herbivores in autumn. Small copepods, Oithona similis and Triconia borealis, were the most numerous omnivorous species in both seasons, but their abundances increased in autumn. Chaetognatha (mainly Eukrohnia hamata) accounted for the highest abundance and biomass among predatory taxa at all deep-water stations and during both seasons. Regarding vertical distribution, herbivores dominated numerically in the surface layer (0-20 m), and omnivores were concentrated somewhat deeper (20-50 m) during both seasons. Maximum abundance of predators was found in the surface layer (0-20 m) in spring, and generally in the 20-50 m layer in autumn. This paper presents the first comprehensive summary of the zooplankton trophic structure in the Fram Strait area. Our goals are to improve understanding of energy transfer through this ecosystem, and of potential climate-induced changes in Arctic marine food webs.

  7. Crustacean zooplankton species richness in Chilean lakes and ponds (23°-51°S)

    OpenAIRE

    Patricio De los Ríos-Escalante

    2013-01-01

    Chilean inland-water ecosystems are characterized by their low species-level biodiversity. This study analyses available data on surface area, maximum depth, conductivity, chlorophyll-α concentration, and zooplankton crustacean species number in lakes and ponds between 23° and 51°S. The study uses multiple regression analysis to identify the potential factors affecting the species number. The partial correlation analysis indicated a direct significant correlation between chlorophyll-α concent...

  8. 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.

    M/μL using the Southern Hybridization Kit (Bangalore Genei, India), following the manufacturer’s instructions. Streptavidin conjugated to alkaline phosphatase (ALP) (Sigma) was used as conjugate and 5-Bromo-4-chloro-3-indolyl phosphate/nitro blue... Technologies, Germany) as per the protocol of the manufacturer. Apart from the 29 isolates, 2 aplanochytrid isolates (S1961 and S19615) obtained from oceanic zooplankton and 9 more isolates obtained from detritus and sediments of mangrove regions (Chorao...

  9. Gelatinous zooplankton biomass in the global oceans: geographic variation and environmental drivers

    OpenAIRE

    Lucas, Cathy H.; Jones, Daniel O. B.; Hollyhead, Catherine J.; Condon, Robert H.; Duarte, Carlos M.; Graham, William M.; Robinson, Kelly L.; Pitt, Kylie A.; Schildhauer, Mark; Regetz, Jim

    2014-01-01

    Aim: Scientific debate regarding the future trends, and subsequent ecological, biogeochemical and societal impacts, of gelatinous zooplankton (GZ) in a changing ocean is hampered by lack of a global baseline and an understanding of the causes of biogeographic patterns. We address this by using a new global database of GZ records to test hypotheses relating to environmental drivers of biogeographic variation in the multidecadal baseline of epipelagic GZ biomass in the world's oceans. Lo...

  10. Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987--1990

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J.

    1990-01-01

    The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO{sub 2}, CH{sub 4}, and N{sub 2}O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. 14 figs., 3 tabs.

  11. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    Science.gov (United States)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  12. Coupling of wave and circulation models in coastal-ocean predicting systems: a case study for the German Bight

    Directory of Open Access Journals (Sweden)

    J. Staneva

    2015-12-01

    Full Text Available This study addresses the impact of coupling between wind wave and circulation models on the quality of coastal ocean predicting systems. This is exemplified for the German Bight and its coastal area known as the Wadden Sea. The latter is the area between the barrier islands and the coast. This topic reflects the increased interest in operational oceanography to reduce prediction errors of state estimates at coastal scales, which in many cases are due to unresolved nonlinear feedback between strong tidal currents and wind-waves. In this study we present analysis of wave and hydrographic observations, as well as results of numerical simulations. A nested-grid modelling system is used to producing reliable nowcasts and short-term forecasts of ocean state variables, including wind waves and hydrodynamics. The data base includes ADCP observations and continuous measurements from data stations. The individual and collective role of wind, waves and tidal forcing are quantified. The performance of the forecast system is illustrated for the cases of several extreme events. Effects of ocean waves on coastal circulation and sea level are investigated by considering the wave-dependent stress and wave breaking parameterization. Also the effects which the circulation exerts on the wind waves are tested for the coastal areas using different parameterizations. The improved skill of the coupled forecasts compared to the non-coupled ones, in particular during extreme events, justifies the further enhancements of coastal operational systems by including wind wave models.

  13. Influence of El Niño Wind Stress Anomalies on South Brazil Bight Ocean Volume Transports

    Directory of Open Access Journals (Sweden)

    Luiz Paulo de Freitas Assad

    2015-01-01

    Full Text Available The knowledge of wind stress variability could represent an important contribution to understand the variability over upper layer ocean volume transports. The South Brazilian Bight (SBB circulation had been studied by numerous researchers who predominantly attempted to estimate its meridional volume transport. The main objective and contribution of this study is to identify and quantify possible interannual variability in the ocean volume transport in the SBB induced by the sea surface wind stress field. A low resolution ocean global circulation model was implemented to investigate the volume transport variability. The results obtained indicate the occurrence of interannual variability in meridional ocean volume transports along three different zonal sections. These results also indicate the influence of a wind driven large-scale atmospheric process that alters locally the SBB and near-offshore region wind stress field and consequently causes interannual variability in the upper layer ocean volume transports. A strengthening of the southward flow in 25°S and 30°S was observed. The deep layer ocean volume transport in the three monitored sections indicates a potential dominance of other remote ocean processes. A small time lag between the integrated meridional volume transports changes in each monitored zonal section was observed.

  14. Zooplankton variation in relation to hydrology in an enclosed hypoxic bay (Amvrakikos Gulf, Greece

    Directory of Open Access Journals (Sweden)

    G. KEHAYIAS

    2014-09-01

    Full Text Available This study investigated the temporal and spatial variation of the zooplankton community of a hypoxic coastal embayment (Amvrakikos Gulf, western Greece in relation to hydrological characteristics during an annual cycle. The main hydrological feature was the prolonged water stratification, which determined hypoxic conditions in the deeper layers that became anoxic close to the bottom in September, while vertical mixing occurred for a very short period (October-November. The total zooplankton abundance fluctuated between 44.6 and 159.7 ind l-1. Fourteen groups were recorded, among which copepods dominated accounting on average for 86.4 %. Most of the groups presented higher abundance values in winter and spring when increased chlorophyll-α concentrations were found. Oxygen depletion affects the vertical distribution of most zooplankton groups and the vertical habitat partitioning between copepod orders and their ontogenetic stages. Several taxa were recorded even in the deep, anoxic layers, but only the polychaete larvae increased in abundance with depth. Calanoids, appendicularians and bivalve larvae presented eastward decrease of abundance in the deepest layers following the same pattern of oxygen decrease. Notwithstanding hypoxic conditions in its deepest layers, Amvrakikos Gulf was accounted for a mesotrophic ecosystem, with the nutrient concentration being lower than in the past. Several biotic elements indicate that the gulf is in a transitional phase towards a better quality state and these results reinforce the need for consistent monitoring of this ecosystem.

  15. 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.

  16. The vertical distribution of zooplankton in the eastern Gulf of Mexico

    Science.gov (United States)

    Hopkins, Thomas L.

    1982-09-01

    The zooplankton community in the eastern Gulf of Mexico was investigated to determine the quantity and taxonomic composition of forage available to higher trophic levels and to provide a data base for future trophodynamic modelling. Standing stock (1.2 g m -2, dw) in the upper 1000 m is in the range for oligotrophic low-latitude boundary currents but is greater than in central gyre areas. Abundance decreases exponentially with depth, over half the biomass occuring in the upper 200 m. Diel variations are apparent, the greatest differences in biomass occuring in the upper 50 m and at 300 to 350 m. Copepods were dominant, contributing over 80% of the number and half the net-caught biomass. The zooplankton community is diverse, 21 genera individually exceeding 1% of the biomass in the 0 to 100-m layer. Grazers (herbivores, detritivores, omnivores) were 66% of the 0 to 1000-m standing stock and carnivores 34%, their biomass in the epipelagic zone above the base of the thermocline (150 m) at night increasing 46 and 57%, respectively. Zooplankton biomass available as forage for higher trophic levels is most concentrated in the upper 50 m, whereas, paradoxically, the zooplanktivorous micronekton, the myctophid fishes in particular, are centered deeper, primarily between 50 and 150 m.

  17. A multivariate approach to environmental-zooplankton relationships in Maldonado Bay (Uruguay

    Directory of Open Access Journals (Sweden)

    Ana Milstein

    1986-01-01

    Full Text Available Environment-zooplankton relationships were analysed in Maldonado Bay (Uruguay, an estuarine area between the River Plate and the Atlantic Ocean. This was done through Principal Component Analysis. Most of the environment variability is accounted for, primarily, by the outflow of the River Plate and the inflow of coastal waters which change through the annual cycle, and in the second place by surface water conditions. On the other hand, most of the zooplankton variability is accounted for by 17 taxa abundant in April and February and by one dominant species present only from May to August. A second source of zooplanktonic variability is due to species which occurred in fall only The main observed variabili ty occurred on an annual scale. On it, variations on smaller scales overlap: from one day to another, between Maldonado Bay and the adjacent waters of the River Plate. The main factors involved were different at each scale. The Bay is relatively isolated from adjacent waters, but the degree of isolation varies throughout the year. The influence of coastal water is greater and occurs first outside the Bay. Biological processes may develop under different conditions in the Bay and in the adjacent waters of the River Plate.

  18. 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.

  19. Predator evasion in zooplankton is suppressed by polyunsaturated fatty acid limitation.

    Science.gov (United States)

    Brzeziński, Tomasz; von Elert, Eric

    2015-11-01

    Herbivorous zooplankton avoid size-selective predation by vertical migration to a deep, cold water refuge. Adaptation to low temperatures in planktonic poikilotherms depends on essential dietary lipids; the availability of these lipids often limits growth and reproduction of zooplankton. We hypothesized that limitation by essential lipids may affect habitat preferences and predator avoidance behavior in planktonic poikilotherms. We used a liposome supplementation technique to enrich the green alga Scenedesmus obliquus and the cyanobacterium Synecchococcus elongatus with the essential lipids, cholesterol and eicosapentaenoic acid (EPA), and an indoor system with a stratified water-column (plankton organ) to test whether the absence of these selected dietary lipids constrains predator avoidance (habitat preferences) in four species of the key-stone pelagic freshwater grazer Daphnia. We found that the capability of avoiding fish predation through habitat shift to the deeper and colder environment was suppressed in Daphnia unless the diet was supplemented with EPA; however, the availability of cholesterol did not affect habitat preferences of the tested taxa. Thus, their ability to access a predator-free refuge and the outcome of predator-prey interactions depends upon food quality (i.e. the availability of an essential fatty acid). Our results suggest that biochemical food quality limitation, a bottom-up factor, may affect the top-down control of herbivorous zooplankton. PMID:26232092

  20. Biotic Spectrum of Chando Lake in Context of Ecological Status and Zooplankton Diversity

    Directory of Open Access Journals (Sweden)

    Anuradha Shukla

    2012-11-01

    Full Text Available Covering an area of approximate 650 ha, Chando Lake is located in South East of Basti, (U.P.. No precise study regarding its hydrobiology has been conducted. Hence, present study has been undertaken to observe its ecological status and zooplankton diversity from June 2010 to May 2012. The early mean flow in this lake relied on rains and the mean annual rain fall was recorded to be 1094 cm with in 51 average rainy days. The average value of the temperature was recorded to be 28.46°C, pH 7.38, transparency 58.52 cm, DO 6024 mg/L, free CO2 3.70 mg/L, TDS 1 52.20 mg/L, total hardness 153.69 mg/L , total alkalinity 272.44 mg/L , Nitrate 7.11 mg/L, phosphate 0.83 mg/L and chloride 34.63 mg/L. In the present study 23 species of zooplankton were noticed out of which six species belong to cladocerans, six species of copepods, four species of protozoans and seven species of rotiferans. The study of zooplankton species diversity and abundance with respect to biotic factors may assist in future planning for the management of intensive fish culture in this vast lake.

  1. Population attenuation in zooplankton communities during transoceanic transfer in ballast water.

    Science.gov (United States)

    Ghabooli, Sara; Zhan, Aibin; Paolucci, Esteban; Hernandez, Marco R; Briski, Elizabeta; Cristescu, Melania E; MacIsaac, Hugh J

    2016-09-01

    Successful biological invasion requires introduction of a viable population of a nonindigenous species (NIS). Rarely have ecologists assessed changes in populations while entrained in invasion pathways. Here, we investigate how zooplankton communities resident in ballast water change during transoceanic voyages. We used next-generation sequencing technology to sequence a nuclear small subunit ribosomal DNA fragment of zooplankton from ballast water during initial, middle, and final segments as a vessel transited between Canada and Brazil. Operational taxonomic unit (OTU) diversity decreased as voyage duration increased, indicating loss of community-based genetic diversity and development of bottlenecks for zooplankton taxa prior to discharge of ballast water. On average, we observed 47, 26, and 24 OTUs in initial, middle, and final samples, respectively. Moreover, a comparison of genetic diversity within taxa indicated likely attenuation of OTUs in final relative to initial samples. Abundance of the most common taxa (copepods) declined in all final relative to initial samples. Some taxa (e.g., Copepoda) were represented by a high number of OTUs throughout the voyage, and thus had a high level of intraspecific genetic variation. It is not clear whether genotypes that were most successful in surviving transit in ballast water will be the most successful upon introduction to novel environments. This study highlights that population bottlenecks may be common prior to introduction of NIS to new ecosystems. PMID:27648234

  2. 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). PMID:24461782

  3. Pelagic and sympagic contribution of organic matter to zooplankton and vertical export in the Barents Sea marginal ice zone

    Science.gov (United States)

    Tamelander, Tobias; Reigstad, Marit; Hop, Haakon; Carroll, Michael L.; Wassmann, Paul

    2008-10-01

    The structure and function of the marine food web strongly regulate the cycling of organic matter derived from primary production by phytoplankton and ice algae in Arctic shelf seas. Improved knowledge of trophic relationships and export of organic matter from the surface layer is needed to better understand how the Arctic marine ecosystem may respond to climate-related changes in distribution of sea ice, water masses, and associated primary production regimes. Pelagic and sympagic inputs of organic matter to dominant meso- and macrozooplankton species and vertical export were investigated in the northern Barents Sea by means of stable carbon and nitrogen isotopes (δ 13C and δ 15N). Samples were collected during spring and summer (2003-2005) from a total of 13 stations with different ice conditions, abundances of ice algae, and phytoplankton bloom phases. δ 13C signatures were different in organic matter of phytoplankton (mean -24.3‰) and ice algal origin (mean -20.0‰). Stable carbon isotope compositions showed that most of the energy assimilated by zooplankton originated from pelagic primary production, but at times ice algae also contributed to zooplankton diets. Trophic level (TL) estimates of copepods ( Calanus glacialis and Calanus hyperboreus) and krill ( Thysanoessa inermis and Thysanoessa longicaudata), calculated based on δ 15N values, varied among stations from 1.3 to 2.7 and from 1.5 to 3.1, for respective taxa. TL in C. glacialis was significantly and inversely related to the depth-integrated phytoplankton chlorophyll a concentration. A similar trend, although weaker, also was observed for the other species. This relationship indicates that copepods graze primarily on the abundant autotrophic biomass during the peak bloom phase. At stations with lower chlorophyll a concentration, the TL of Calanus spp. was 1.0 higher, indicating omnivory outside the peak bloom phase in response to changed food availability. The majority of organic matter

  4. Initial size structure of natural phytoplankton communities determines the response to Daphnia diel vertical migration

    OpenAIRE

    Maarten Boersma; Florian Haupt; Maria Stockenreiter; Herwig Stibor

    2012-01-01

    Diel vertical migration (DVM) is a common behavior of many pelagic herbivorous zooplankton species in response to predation pressure. It is characterized by a twice daily habitat shift of the zooplankton species: staying in the epilimnion only during night time and migrating down in the crack of dawn in deeper water layers, staying there during the day time. This causes a discontinuous grazing regime and previous studies have shown that the direction and strength of phytoplankton community re...

  5. Effects of the proximal factors on the diel vertical migration of zooplankton in a plateau meso-eutrophic Lake Erhai, China

    Directory of Open Access Journals (Sweden)

    Cuilin Hu

    2014-03-01

    Full Text Available To study the proximal factors inducing diel vertical migration (DVM in large and small zooplankton species in a plateau lake in China, we investigated the DVM of crustacean zooplankton in lake Erhai bimonthly from November 2009 to September 2010. We hypothesized that the factors affecting DVM behaviour in different-sized zooplankton were different. A linear regression was used to assess the relationships between environmental variables and the vertical distribution of zooplankton. All crustacean zooplankton exhibited normal DVM patterns (down during the day, up at night across sampling months. The weighted mean depth (WMD of all zooplankton did not show a significant correlation with the WMD of the dominant phytoplankton and chlorophyll-a. However, a negative relationship was observed between the distribution of zooplankton and water temperature in January, March, and July 2010, but the relationship was relatively weak (R2 between 0.1 and 0.4. The vertical distribution of zooplankton was primarily affected by water transparency (P0.05, whereas the factors inducing DVM behaviour differed between large and small zooplankton. Predation avoidance and phototactic behaviour may be the dominant factors influencing DVM of large species, whereas only phototaxis contributed to the migratory behaviour of small species.

  6. Determination of the rate and efficiency of nitrogen transfer from phytoplankton to zooplankton using nitrogen-15 as a tracer. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harris, V M

    1976-02-23

    The rate of assimilated nitrogen transfer from phytoplankton to zooplankton was measured under field conditions for natural mixed zooplankton populations using a nitrogen-15 tracer technique. The variability in rates, which ranged from 0.261 to 1.792 gram-atoms of phytoplankton nitrogen/gram-atoms of zooplankton nitrogen/24 hours, are thought to reflect a variability in the age frequency distribution of the zooplankton population. The data were used to calculate assimilation efficiencies which were found to range from 25.4 to 66.1 percent. The efficiency of 66.1 percent was taken to be the most accurate measurement for reasons discussed in the text.

  7. Biomixing due to diel vertical migrations of zooplankton: Comparison of computational fluid dynamics model with observations

    Science.gov (United States)

    Dean, Cayla; Soloviev, Alexander; Hirons, Amy; Frank, Tamara; Wood, Jon

    2016-02-01

    Recent studies (Dewar et al., 2006; Wilhelmus and Dabiri, 2014) suggest that diel vertical migrations (DVM) of zooplankton (or other migrating organisms) may have an impact on ocean mixing, though details are not completely clear. Zooplankton that undergo DVM can have an impact on oil transport through the water column, and oil and dispersants can have a negative or even lethal effect on the organisms. Kunze et al. (2006) reported an increase of dissipation rate of turbulent kinetic energy, ε, by four to five orders of magnitude during DVM of zooplankton over background turbulence in Saanich Inlet, British Columbia, Canada. However, the effect was not observed in the same area by Rousseau et al. (2010) and was later reassessed by Kunze (2011). In our work, an 11-month data set obtained in the Straits of Florida with a bottom-mounted acoustic Doppler current profiler revealed strong sound scattering layers undergoing DVM. We used a 3-D 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 based on measurements by Greenlaw (1979) and Mackie and Mills (1983) in Saanich Inlet. At a concentration close to the upper limit, the simulation showed an increase in ε by two to three orders of magnitude during DVM over background turbulence, 10-9 W kg-1. At a concentration of 1000 organisms/m3, almost no turbulence above the background level was produced in the model. These results suggest that the Kunze et al. (2006) observations could have been performed at a larger concentration of migrating zooplankton than those reported by Rousseau et al. (2010). No exact zooplankton concentrations data were provided in either work. The difference between observations and the model can, in part, be explained by the fact that Kunze et al. (2006) measured

  8. Meso- and macro-zooplankton community structure of the Amundsen Sea Polynya, Antarctica (Summer 2010–2011

    Directory of Open Access Journals (Sweden)

    Stephanie E. Wilson

    2015-01-01

    Full Text Available Abstract The Amundsen Sea Polynya (ASP has, on average, the highest productivity per unit area in Antarctic waters. To investigate community structure and the role that zooplankton may play in utilizing this productivity, animals were collected at six stations inside and outside the ASP using paired “day-night” tows with a 1 m2 MOCNESS. Stations were selected according to productivity based on satellite imagery, distance from the ice edge, and depth of the water column. Depths sampled were stratified from the surface to ∼ 50–100 m above the seafloor. Macrozooplankton were also collected at four stations located in different parts of the ASP using a 2 m2 Metro Net for krill surface trawls (0–120 m. The most abundant groups of zooplankton were copepods, ostracods, and euphausiids. Zooplankton biovolume (0.001 to 1.22 ml m-3 and abundance (0.21 to 97.5 individuals m-3 varied throughout all depth levels, with a midsurface maximum trend at ∼ 60–100 m. A segregation of increasing zooplankton trophic position with depth was observed in the MOCNESS tows. In general, zooplankton abundance was low above the mixed layer depth, a result attributed to a thick layer of the unpalatable colonial haptophyte, Phaeocystis antarctica. Abundances of the ice krill, Euphausia crystallarophias, however, were highest near the edge of the ice sheet within the ASP and larvae:adult ratios correlated with temperature above a depth of 60 m. Total zooplankton abundance correlated positively with chlorophyll a above 150 m, but negative correlations observed for biovolume vs. the proportion of P. antarctica in the phytoplankton estimated from pigment ratios (19’hexanoyloxyfucoxanthin:fucoxanthin again pointed to avoidance of P. antarctica. Quantifying zooplankton community structure, abundance, and biovolume (biomass in this highly productive polynya helps shed light on how carbon may be transferred to higher trophic levels and to depth in a region undergoing

  9. Community structure of zooplankton in the main entrance of Bahía Magdalena, México during 1996.

    Science.gov (United States)

    Gómez-Gutiérrez, J; Palomares-García, R; Hernández-Trujillo, S; Carballido-Carranza, A

    2001-06-01

    The zooplankton community structure, including copepods, euphausiids, chaetognaths, and decapod larvae, was monitored during six circadian cycles using Bongo net (500 microns mesh net) samples from Bahía Magdalena, on the southwest coast of Baja California, México. Samples were obtained during three oceanographic surveys (March, July, and December 1996) to describe the changes in the zooplankton community structure throughout the main mouth of Bahía Magdalena. The zooplankton community structure showed strong changes with a close relation to environmental conditions. During March, a well-mixed water column with low temperature and salinity indicated an influence of the California Current water and local upwelling processes. During July, temperature increased and a wide salinity range was recorded. The stratification of the water column was intense during summer, enhancing the thermocline. The highest temperatures and salinity were recorded in December, related to the presence of the Costa Rica Coastal Current (CRCC). The thermocline deepened as water temperature increased. A typical temperate community structure with low specific richness dominated by Calanus pacificus, Nyctiphanes simplex, and Acartia clausi and high zooplankton biomass (average 9.3 and 5.5 ml 1000 m-3 respectively) during March and July shifted to a more complex tropical community structure with a low zooplankton biomass in December (average 0.37 ml 1000 m-3). The mouth of Bahía Magdalena has a vigorous exchange of water caused by tidal currents. The zooplankton community structure was not significantly different between the central part of Bahía Magdalena and the continental shelf outside the bay for all months. The results suggest a more dynamic inside-outside interaction of zooplankton assemblages than first thought. PMID:11935905

  10. Spatial and temporal variations of zooplankton composition and quantity distribution in the upper waters around Nansha Islands

    Institute of Scientific and Technical Information of China (English)

    YIN Jianqiang; CHEN Qingchao; ZHANG Guxian; HUANG Liangmin; LI Kaizhi

    2006-01-01

    This study aims to examine spatial and temporal variations of zooplankton species composition, density and biomass distribution and community structure, based on the data obtained from three separate cruises carried out in November 1997, April and July 1999. Results show that 244 species of zooplankton and 8 groups of planktonic larvae were identified, which were dominated by copepods, followed by amphipods, ostracods and medusae. The total species were 201 and 198 for the cruises of November 1997 and July 1999, respectively, and no obvious seasonal variation of species richness was observed. The distribution of zooplankton species richness decreased from pelagic to coastal waters.Average richness of species in each station was higher in the cruises of November 1997(62) and April 1999(61) than in the cruise in July 1999 (56), which was mainly a result from the pelagic or coastal water mass movement made by the monsoon. Zooplankton in the upper waters (0-100 m) around Nansha Islands belonged to the typical tropic pelagic fauna,most of them were pelagic warm-water species, followed by coastal warm-water species and euryhaline warm-water species. The number of dominant species ranged from 5 to 7 in each cruise. No obvious seasonal succession of dominant species was observed. Sagitta enflata, Cypridina nami, Cosmocalanus darwinii, Pleuromamma gracilis and Echinopluteus larva were the main dominant species. The average of zooplankton biomass and density in three cruises were 31, 32, 28 mg.m-3 and 31, 39, 35 ind.m-3, respectively. Copepods were the most abundant, followed by chaetognaths. Zooplankton high biomass distributed mainly in the northwestern waters around Nansha Islands, and generally occurred in the areas of oceanic front and upwelling.The main reason for zooplankton quantity without obvious seasonal variation was the relative steady temperature dynamics in the waters around Nansha Islands.

  11. Zooplankton diel vertical migration and influence of upwelling on the biomass in the Chukchi Sea during summer

    Institute of Scientific and Technical Information of China (English)

    WANG Huiwu; CHEN Hongxia; XUE Liang; LIU Na; LIU Yanliang

    2015-01-01

    The diel vertical migration (DVM) of zooplankton and the influence of upwelling on zooplankton biomass were examined using water column data of current velocity and mean volume backscattering strength (MVBS) collected by moored acoustic Doppler current profilers (ADCPs) deployed in the southeastern Chukchi Sea during the 5th Chinese National Arctic Research Expedition (CHINARE) in summer 2012, combined with the satellite observational data such as sea surface temperature (SST), wind, and chlorophylla (Chla). Hourly acoustic data were continuously collected for 49-d in the mooring site. Spectral analysis indicated that there were different migrating patterns of zooplankton, even though precisely classifying the zooplankton taxa was not available. The prevailing 24-h cycle corresponded to the normal DVM with zooplankton swimming upwards at sunrise and returning to deep waters at sunset. There was a clear DVM in the upper 17 m of the water column during the period with distinct day-night cycles, and no active DVM throughout the water column when the sun above the horizon (polar day), suggesting that light intensity was the trigger for DVM. Also there was a second migrating pattern with 12-h cycle. The upwelling event occurring in the northwest of Alaskan coastal area had important influence on zooplankton biomass at the mooring site. During the upwelling, the SST close to the mooring site dropped significantly from maximal 6.35℃ to minimal 1.31℃ within five days. Simultaneously, there was a rapid increase in the MVBS and Chla level, suggesting the aggregation of zooplankton related to upwelling.

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

    Science.gov (United States)

    Cisewski, Boris; Strass, Volker H.

    2016-05-01

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

  13. INCREASING THE PRODUCTIVITY OF ZOOPLANKTON COMMUNITIES WITH THE USE OF EKOVITAL AND VETCH-OAT GRASS

    Directory of Open Access Journals (Sweden)

    N. Tson’

    2015-10-01

    Full Text Available Purpose. To investigate the potential of zooplankton productivity in aquatic ecosystems under experimental conditions of the microcosms with the use of the green fertilizer (vetch-oat grass and Ekovital. Methodology. The study was conducted under the conditions of model ecosystems (microcosms installed in fish-breeding ponds. We used a complex of intensification measures (enhancement, inoculation of vetch-oat seed mixture (1:1 with Ekovital at quantities of 1.4; 2.9; 4.3 ml/kg (variants D1, D2, D3, followed by sowing the pond beds with the vetch-oat mixture (1:1, growing of vetch-oat grass for the green fertilizer. The seeds were sown at a ratio of 70 kg of grains for 1 ha of ponds area. The first control variant (K1 — without green fertilizer and without preparation. The second control version (K2 vetch-oat seeds were soaked in the corresponding quantity of water without preparation and after they were sown on the pond bed. The preparation Ekovital contains specific nitrogen-fixing nodule Rhizobium leguminosarum and phosphorus mobilizing Bacillus megaterium-6 bacteria. Hydrochemical, hydrobiological, fisheries, and statistical studies were conducted according to standard methods. Findings. It was found that the application of Ekovital in a combination with enhancement activities gives an opportunity to obtain a green fertilizer of up to 1.03 ± 0.08 t/ha during 40 days for increasing pond ecosystem productivity. The stimulation of zooplankton development gave an opportunity to obtain the maximum biomass of 9.85–31.78 g/m3 that was 4–16 times higher than in that in the control — 2.54–3.30 g/m3. The mean values of zooplankton biomass in the experiments were 4.30–9.17 g/m3, that was 3-9 times higher than those in the control — 1.06–1.40 g/m3. The experimental variants showed a tendency for increasing the share of cladoceran crustaceans. The production of zooplankton organisms was increased to 1834.8 kg/ha — the level of the most

  14. A study of sediment motions and bottom layer dynamics over the Middle Atlantic Bight shelf and upper slope. Final technical report, 1 June 1992--31 May 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pietrafesa, L.J.

    1995-12-31

    A study of sediment dynamics over the Middle Atlantic Bight (MAB) in the vicinity of the Cape Hatteras Confluence (CHC), including the mouths of estuaries, the shelf and the slope, was carried out by investigators at North Carolina State University as part of the Department of Energy Ocean Margins Program. Studied were processes effecting sediment motion. In particular, the processes which determine rates of vertical transport of dissolved carbon dioxide and organic matter and particulates to and from the bottom by turbulent mixing resuspension and particulate sinking and vertical motions induced by BBL convergences; especially during periods of storm activity when both surface waves and currents are maxima.

  15. Zooplankton and aggregates as refuge for aquatic bacteria: protection from UV, heat and ozone stresses used for water treatment.

    Science.gov (United States)

    Tang, Kam W; Dziallas, Claudia; Grossart, Hans-Peter

    2011-02-01

    Aggregates and zooplankton may provide refuge for aquatic bacteria against external hazards. The ability of attached bacteria to survive and recover from stressors commonly used for water treatment was tested in the laboratory. Without zooplankton or aggregates, both UV and ozone significantly reduced abundance of free-living bacteria in both freshwater and marine medium. The presence of zooplankton carcasses and aggregates, however, allowed some of the attached bacteria to survive and recover quickly within 3 days. Heat exposure was the least effective as both free-living and attached bacteria were able to recover quickly. Selective survival of bacterial phylotypes led to large changes in bacterial community composition after stress exposures, and some of the bacteria that recovered belonged to groups with known pathogens. This study demonstrates that zooplankton and aggregates protected various aquatic bacteria from external stressors, and organic remains generated from zooplankton and aggregates after stress exposure even enabled the surviving bacteria to quickly regrow and subsequently be released into the surrounding water. Hence, water disinfection treatments that overlooked the potential persistence of bacteria associated with organisms and aggregates may not be effective in preventing the spread of undesirable bacteria.

  16. A case study of an enhanced eutrophication model with stoichiometric zooplankton growth sub-model calibrated by Bayesian method.

    Science.gov (United States)

    Yang, Likun; Peng, Sen; Sun, Jingmei; Zhao, Xinhua; Li, Xia

    2016-05-01

    Urban lakes in China have suffered from severe eutrophication over the past several years, particularly those with relatively small areas and closed watersheds. Many efforts have been made to improve the understanding of eutrophication physiology with advanced mathematical models. However, several eutrophication models ignore zooplankton behavior and treat zooplankton as particles, which lead to the systematic errors. In this study, an eutrophication model was enhanced with a stoichiometric zooplankton growth sub-model that simulated the zooplankton predation process and the interplay among nitrogen, phosphorus, and oxygen cycles. A case study in which the Bayesian method was used to calibrate the enhanced eutrophication model parameters and to calculate the model simulation results was carried out in an urban lake in Tianjin, China. Finally, a water quality assessment was also conducted for eutrophication management. Our result suggests that (1) integration of the Bayesian method and the enhanced eutrophication model with a zooplankton feeding behavior sub-model can effectively depict the change in water quality and (2) the nutrients resulting from rainwater runoff laid the foundation for phytoplankton bloom. PMID:26780061

  17. 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.

  18. Vertical redistribution of zooplankton in an oligotrophic lake associated with reduction in ultraviolet radiation by wildfire smoke

    Science.gov (United States)

    Urmy, Samuel S.; Williamson, Craig E.; Leach, Taylor H.; Schladow, S. Geoffrey; Overholt, Erin P.; Warren, Joseph D.

    2016-04-01

    We used a natural experiment to test whether wildfire smoke induced changes in the vertical distribution of zooplankton in Lake Tahoe by decreasing incident ultraviolet radiation (UV). Fires have a variety of effects on aquatic ecosystems, but these impacts are poorly understood and have rarely been observed directly. UV is an important driver of zooplankton vertical migration, and wildfires may alter it over large spatial scales. We measured UV irradiance and the distribution of zooplankton on two successive days. On one day, smoke haze from a nearby wildfire reduced incident UV radiation by up to 9%, but not irradiance in the visible spectrum. Zooplankton responded by positioning themselves, on average, 4.1 m shallower in the lake. While a limited data set such as this requires cautious interpretation, our results suggest that smoke from wildfires can change the UV environment and distribution of zooplankton. This process may be important in drought-prone regions with increasingly frequent wildfires, and globally due to widespread biomass burning.

  19. [Effects of large bio-manipulation fish pen on community structure of crustacean zooplankton in Meiliang Bay of Taihu Lake].

    Science.gov (United States)

    Ke, Zhi-Xin; Xie, Ping; Guo, Long-Gen; Xu, Jun; Zhou, Qiong

    2012-08-01

    In 2005, a large bio-manipulation pen with the stock of silver carp and bighead carp was built to control the cyanobacterial bloom in Meiliang Bay of Taihu Lake. This paper investigated the seasonal variation of the community structure of crustacean zooplankton and the water quality within and outside the pen. There were no significant differences in the environmental parameters and phytoplankton biomass within and outside the pen. The species composition and seasonal dynamics of crustacean zooplankton within and outside the pen were similar, but the biomass of crustacean zooplankton was greatly suppressed by silver carp and bighead carp. The total crustacean zooplankton biomass and cladocerans biomass were significantly lower in the pen (P carp and bighead carp exerted more pressure on cladoceran species than on copepod species. A distinct seasonal succession of crustacean zooplankton was observed in the Bay. Many crustacean species were only dominated in given seasons. Large-sized crustacean (mainly Daphnia sp. and Cyclops vicnus) dominated in winter and spring, while small-sized species (mainly Bosmina sp., Ceriodaphnia cornuta, and Limnoithona sinensis) dominated in summer and autumn. Canonical correspondence analysis showed that water transparency, temperature, and phytoplankton biomass were the most important factors affecting the seasonal succession of the crustacean. PMID:23189709

  20. Vorticity and mixing induced by the barotropic M 2 tidal current and zooplankton biomass distribution in the Gulf of California

    Science.gov (United States)

    Salas-de-León, David Alberto; Carbajal, Noel; Monreal-Gómez, Maria Adela; Gil-Zurita, Antonio

    2011-08-01

    Vertical mixing and biological processes in the Gulf of California were analyzed using calculated relative vorticity fields induced by the barotropic M 2 tide and zooplankton biomass distribution. M 2 tidal currents contribute significantly to the general circulation observed in the upper gulf. The results revealed zones with high vertical and horizontal values of relative vorticity in regions where temperature anomalies and water exchange take place. The horizontal component of the vorticity vector is considerable in areas of the upper gulf, where high vertical shear of the velocity was estimated. Patterns of the horizontal component of the vorticity, the Simpson-Hunter criterion and the chlorophyll concentration showed similarities. The interaction of tidal flow with the complex bathymetry is the main source of vorticity and mixing in the gulf. The vertical component of the relative vorticity reaches positive values in regions where cyclonic circulation has been reported. A total of 35 groups of zooplankton were identified in the gulf; Copepoda, Chaetognatha, and Euphausiacea were the three major groups. High zooplankton biomasses in the archipelago region of the gulf were associated with topographic effect, which induces strong shear velocities, creating vertical mixing and increasing the supply of nutrients to the surface layers, which in turn induces high chlorophyll concentration or phytoplankton and thereby supports the zooplankton biomass. The zooplankton biomass was closely related to high values of the horizontal component of relative vorticity.

  1. Differences between Arctic and Atlantic fjord systems on bioaccumulation of persistent organic pollutants in zooplankton from Svalbard.

    Science.gov (United States)

    Hallanger, Ingeborg G; Ruus, Anders; Warner, Nicholas A; Herzke, Dorte; Evenset, Anita; Schøyen, Merete; Gabrielsen, Geir W; Borgå, Katrine

    2011-06-15

    Differences in bioaccumulation of persistent organic pollutants (POPs) between fjords characterized by different water masses were investigated by comparing POP concentrations, patterns and bioaccumulation factors (BAFs) in seven species of zooplankton from Liefdefjorden (Arctic water mass) and Kongsfjorden (Atlantic water mass), Svalbard, Norway. No difference in concentrations and patterns of POPs was observed in seawater and POM; however higher concentrations and BAFs for certain POPs were found in species of zooplankton from Kongsfjorden. The same species were sampled in both fjords and the differences in concentrations of POPs and BAFs were most likely due to fjord specific characteristics, such as ice cover and timing of snow/glacier melt. These confounding factors make it difficult to conclude on water mass (Arctic vs. Atlantic) specific differences and further to extrapolate these results to possible climate change effects on accumulation of POPs in zooplankton. The present study suggests that zooplankton do biomagnify POPs, which is important for understanding contaminant uptake and flux in zooplankton, though consciousness regarding the method of evaluation is important. PMID:21600630

  2. On the mass and salt budgets for a region of the continental shelf in the southern Mid-Atlantic Bight

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoo Yin; Weatherly, Georges L.; Pietrafesa, Leonard J.

    2001-12-01

    Two field studies were conducted across and along the continental shelf, one from February to May 1996 (deployment 1) and the other from July to October 1996 (deployment 2), in part to determine the mass and salt budgets of shelf water from south of Cape Henry to north of Cape Hatteras, the southernmost portion of the Mid-Atlantic Bight. The temporal means of current meter records indicated that most of the water enters the region across its northern boundary near the shelf break as part of a southward, alongshore current and exits the southeast corner as a southeastward flowing current. Estimates of the volume transports indicated that not all the transport across the northern boundary was accounted for by transport across the southern boundary, and that the remainder occurred as a broad, diffusive flow across the eastern boundary at the shelf break. Time series of volume transport across northern and southern boundaries were very similar and associated with variations in the alongshore wind stress and sea level, indicative of a geostrophic balance. Examination of the individual current meter records indicated these fluctuations were very barotropic even during deployment 2, which included the stratified summer season. Time series of the volume transport across the eastern boundary at the shelf break strongly mirrored the volume transport across the northern boundary minus that across the southern boundary, suggesting that the inferred eastern boundary transport was real and accommodated whatever the southern boundary could not. The turbulent salt flux across each boundary contributes very little to the net respective mass fluxes because the salt fluxes are almost governed by current velocity fields. The instantaneous and mean salt fluxes across each boundary were very well approximated by the instantaneous and mean volume transports across the boundary times the deployment average salinity across that boundary, respectively. The Ocean Margins Program (OMP) moored

  3. 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...

  4. Zooplankton, temperature, salinity, and nutrients data from bottle and net casts in the Flores Sea from the SAMUDERA from 14 July 1976 to 26 July 1976 (NODC Accession 0000672)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, phytoplankton, nutrients, and other data were collected using bottles and nets from the SAMUDERA from 14 July 1976 to 26 July 1976 . Zooplankton data...

  5. Feeding and filtration rates of zooplankton (rotifers and cladocerans) fed toxic cyanobacterium (Microcystis aeruginosa).

    Science.gov (United States)

    Pérez-Morales, Alfredo; Sarma, S S S; Nandini, S

    2014-11-01

    Microcystis aeruginosa is generally dominant in many Mexican freshwater ecosystems interacting with zooplankton species. Hence, feeding and filtration rates were quantified for three cladoceran (Daphnia pulex, Moina micrura and Ceriodaphnia dubia) and three rotifer species (Brachionus calyciflorus, Brachionus rubens and Plationus patulus) using sonicated M. aeruginosa alone or mixed with Scenedesmus acutus in different proportions (25, 50 and 75%, based on cell density), offering a combined initial density of 100,000 cells·ml(-1). All the three cladoceran species ingested M. aeruginosa (100-300 cells ind(-1) min(-1)) when fed exclusively with cyanobacterium. When green alga offered as exclusive diet, the number of cells ingested by the tested cladocerans varied from 80 to 400 cells ind(-1) min(-1). Compared to cladocerans, rotifers in general consumed much lower quantity (< 200 cells ind(-1) min(-1)) of M. aeruginosa and S. acutus. The filtration rate for Daphnia pulex was inversely related to the proportion of green alga in the diet. For other tested cladocerans, no such clear trend was evident. In mixed treatments containing M. aeruginosa, the filtration rate of Daphnia was highest (about 220 μl ind(-1) min(-1)) when the medium contained 75% of S. acutus. Among the rotifer species, P. patulus filtered highest volume (100 μl ind(-1) min(-1) from mixed diets containing higher proportions (50 or 75%) of M. aeruginosa. Thus, there were species-specific differences in the filtration and feeding rates of zooplankton when offered mixed diets of green algae and toxic cyanobacteria. These probably explain the coexistence of different zooplankton species in Microcystis-dominant waterbodies. PMID:25522500

  6. Does the zooplankton prey availability limit the larval habitats of pike in the Baltic Sea?

    Science.gov (United States)

    Kallasvuo, Meri; Salonen, Maiju; Lappalainen, Antti

    2010-01-01

    The objectives of this study were to (1) investigate whether the availability of suitable zooplankton prey limits the distribution of the coastal larval areas of pike ( Esox lucius) in two archipelago areas of the northern Baltic Sea and (2) compare the availability of zooplankton prey in spring between different types of coastal littoral habitat. According to the results, reed belt habitats formed by Phragmites australis constitute hot spots for zooplankton prey in the coastal ecosystem. During the spring, reed-covered shores of the inner archipelago maintained more than 10 times higher densities of copepods and cladocerans, the preferred prey for larval pike, compared to the other studied shores. Temperature conditions were also most favourable in the reed belt habitat. Thus, the reed belts of the inner and middle archipelago were shown to form the best habitat for larval pike in the coastal area of the northern Baltic Sea, and this was also the only habitat where pike larvae were found. Our results suggest that the poor survival and recruitment of pike in the outer archipelago, however, cannot exclusively be explained by sub-optimal feeding conditions of the larvae. There are also other important factors, presumably connected to the exposure to the open sea, that affect the distribution of the pike larvae. Our results, however, highlight the importance of sheltered coastal reed belt shores as reproduction habitat for spring-spawning fish in the northern Baltic Sea. Further, this study disproves the assumption that the seaweed bladder wrack ( Fucus vesiculosus) forms a reproduction habitat for pike in the coastal area.

  7. Multi-decadal variations in stable N isotopes of California Current zooplankton

    Science.gov (United States)

    Ohman, Mark D.; Rau, Greg H.; Hull, Pincelli M.

    2012-01-01

    We analyzed variations in naturally occurring δ15N in four species of zooplankton as an index of climate influences on pelagic food web structure in a major eastern boundary current ecosystem. Our analyses focused on two species of particle-grazing copepods ( Calanus pacificus and Eucalanus californicus) and two species of carnivorous chaetognaths ( Sagitta bierii and Sagitta euneritica), drawing on the CalCOFI zooplankton time series from both the southern and central sectors of the California Current System. We detected a significant difference between regions in average stable N isotope content of the two species of copepods, with δ15N elevated by 0.5-1.1 per mil in the southern region, but no regional differences in the isotopic content of the chaetognaths. We address climate influences over a 54-year time period, on three different time scales: interannual (dominated by ENSO), decadal, and multi-decadal. Three of four species showed evidence of an ENSO-related isotopic shift toward increased 15N during El Niño conditions. In addition, in Southern California waters, C. pacificus and S. euneritica showed elevated δ15N in the warm phase of the NE Pacific between 1978 and 1998 relative to the preceding and following time periods. When considered over the entire 5½ decades treated here, for most species there was remarkable long-term stability in stable isotope content in both southern and central California waters, despite interannual and decadal perturbations. Only E. californicus in the southern sector showed a significant downward secular trend in δ15N. Variability of δ15N in 3 species covaried with the average nitrate concentration in the mixed layer, suggesting altered nitrate utilization at the base of the food web as a primary mechanism underlying interannual changes in zooplankton isotopic content.

  8. Diel vertical migration of predators (planktivorous fish larvae and prey (zooplankton in a tropical lagoon

    Directory of Open Access Journals (Sweden)

    Marcos Marques Mendonça

    2015-06-01

    Full Text Available ABSTRACT Based on the hypothesis that diel vertical migration (DVM is a mechanism of predator avoidance, the objective of the present study was to test for the occurrence of DVM in planktivorous fish larvae of Hypophthalmus edentatus (Spix, 1829 (Siluriformes, Pimelodidae and Plagioscion squamosissimus (Heckel, 1840 (Perciformes, Sciaenidae, and zooplankton (rotifers, cladocerans and copepods in an isolated tropical lagoon in the floodplain of the Upper Paraná River, Brazil (region of Parque Nacional de Ilha Grande. We investigated spatial overlap between predators (planktivorous fish larvae and prey (zooplankton, and tested which physical and chemical variables of the water are related to the DVM of the studied communities. We performed nocturnal (8:00 pm and 4:00 am and diurnal sampling (8:00 am and 4:00 pm in the limnetic region of the lagoon for six consecutive months, from October 2010 to March 2011, which comprises the reproductive period of the fish species analyzed. During the day the larvae tried to remain aggregated in the bottom of the lagoon, whereas at night they tried to disperse in the water column. Especially for cladocerans, the diel vertical migration is an important behavior to avoid predation larvae of H. edentatus and P. squamosissimus once decreased spatial overlap between secured and its potential predators, which corroborates the hypothesis that DVM is a mechanism of predator avoidance. Although significant correlations were observed between the abiotic factors and WMD of microcrustaceans at certain times of day, the effect of predation of fish larvae on zooplankton showed more important in this environment, because the small depth and isolation not allow great variation of abiotic factors seasonally and between strata the lagoon.

  9. 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

    2016-06-01

    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.

  10. 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.

    Distribution, abundance and species composition of zooplankton collected during the First Indian Antarctic Krill Expedition were studied. Zooplankton biomass values ranged from 9.79 to 303.62 ml 100 m sup(–3) (x bar = 142.14 plus or minus 77...

  11. Zooplankton Growth, Respiration and Grazing on the Australian Margins of the Tropical Indian and Pacific Oceans.

    Directory of Open Access Journals (Sweden)

    A David McKinnon

    Full Text Available The specific activity of aminoacyl-tRNA synthetases (spAARS, an index of growth rate, and of the electron transport system (spETS, an index of respiration, was measured in three size fractions (73-150 μm, >150 μm and >350 μm of zooplankton during five cruises to tropical coastal waters of the Kimberley coast (North West Australia and four cruises to waters of the Great Barrier Reef (GBR; North East Australia. The N-specific biomass of plankton was 3-4-fold higher in the Kimberley than on the GBR in all 3 size classes: Kimberley 1.27, 3.63, 1.94 mg m-3; GBR 0.36, 0.88 and 0.58 mg m-3 in the 73-150 μm, >150 μm and >350 μm size classes, respectively. Similarly, spAARS activity in the Kimberley was greater than that of the GBR: 88.4, 132.2, and 147.6 nmol PPi hr-1 mg protein -1 in the Kimberley compared with 71.7, 82.0 and 83.8 nmol PPi hr-1 mg protein -1 in the GBR, for the 73-150 μm, >150 μm and >350 μm size classes, respectively. Specific ETS activity showed similar differences in scale between the two coasts: 184.6, 148.8 and 92.2 μL O2 hr-1 mg protein-1 in the Kimberley, against 86.5, 88.3 and 71.3 μL O2 hr-1 mg protein-1 in the GBR. On the basis of these measurements, we calculated that >150 μm zooplankton grazing accounted for 7% of primary production in the Kimberley and 8% in GBR waters. Area-specific respiration by >73 μm zooplankton was 7-fold higher in the Kimberley than on the GBR and production by >150 μm zooplankton was of the order of 278 mg C m-2 d-1 in the Kimberley and 42 mg C m-2 d-1 on the GBR. We hypothesize that the much stronger physical forcing on the North West shelf is the principal driver of higher rates in the west than in the east of the continent.

  12. Zooplankton Growth, Respiration and Grazing on the Australian Margins of the Tropical Indian and Pacific Oceans

    Science.gov (United States)

    McKinnon, A. David; Doyle, Jason; Duggan, Samantha; Logan, Murray; Lønborg, Christian; Brinkman, Richard

    2015-01-01

    The specific activity of aminoacyl-tRNA synthetases (spAARS), an index of growth rate, and of the electron transport system (spETS), an index of respiration, was measured in three size fractions (73–150 μm, >150 μm and >350 μm) of zooplankton during five cruises to tropical coastal waters of the Kimberley coast (North West Australia) and four cruises to waters of the Great Barrier Reef (GBR; North East Australia). The N-specific biomass of plankton was 3–4-fold higher in the Kimberley than on the GBR in all 3 size classes: Kimberley 1.27, 3.63, 1.94 mg m-3; GBR 0.36, 0.88 and 0.58 mg m-3 in the 73–150 μm, >150 μm and >350 μm size classes, respectively. Similarly, spAARS activity in the Kimberley was greater than that of the GBR: 88.4, 132.2, and 147.6 nmol PPi hr-1 mg protein -1 in the Kimberley compared with 71.7, 82.0 and 83.8 nmol PPi hr-1 mg protein -1 in the GBR, for the 73–150 μm, >150 μm and >350 μm size classes, respectively. Specific ETS activity showed similar differences in scale between the two coasts: 184.6, 148.8 and 92.2 μL O2 hr-1 mg protein-1 in the Kimberley, against 86.5, 88.3 and 71.3 μL O2 hr-1 mg protein-1 in the GBR. On the basis of these measurements, we calculated that >150 μm zooplankton grazing accounted for 7% of primary production in the Kimberley and 8% in GBR waters. Area-specific respiration by >73 μm zooplankton was 7-fold higher in the Kimberley than on the GBR and production by >150 μm zooplankton was of the order of 278 mg C m-2 d-1 in the Kimberley and 42 mg C m-2 d-1 on the GBR. We hypothesize that the much stronger physical forcing on the North West shelf is the principal driver of higher rates in the west than in the east of the continent. PMID:26469275

  13. Impact of climate change on zooplankton communities, seabird populations and arctic terrestrial ecosystem—A scenario

    Science.gov (United States)

    Stempniewicz, Lech; Błachowiak-Samołyk, Katarzyna; Węsławski, Jan M.

    2007-11-01

    Many arctic terrestrial ecosystems suffer from a permanent deficiency of nutrients. Marine birds that forage at sea and breed on land can transport organic matter from the sea to land, and thus help to initiate and sustain terrestrial ecosystems. This organic matter initiates the emergence of local tundra communities, increasing primary and secondary production and species diversity. Climate change will influence ocean circulation and the hydrologic regime, which will consequently lead to a restructuring of zooplankton communities between cold arctic waters, with a dominance of large zooplankton species, and Atlantic waters in which small species predominate. The dominance of large zooplankton favours plankton-eating seabirds, such as the little auk ( Alle alle), while the presence of small zooplankton redirects the food chain to plankton-eating fish, up through to fish-eating birds (e.g., guillemots Uria sp.). Thus, in regions where the two water masses compete for dominance, such as in the Barents Sea, plankton-eating birds should dominate the avifauna in cold periods and recess in warmer periods, when fish-eaters should prevail. Therefore under future anthropogenic climate scenarios, there could be serious consequences for the structure and functioning of the terrestrial part of arctic ecosystems, due in part to changes in the arctic marine avifauna. Large colonies of plankton-eating little auks are located on mild mountain slopes, usually a few kilometres from the shore, whereas colonies of fish-eating guillemots are situated on rocky cliffs at the coast. The impact of guillemots on the terrestrial ecosystems is therefore much smaller than for little auks because of the rapid washing-out to sea of the guano deposited on the seabird cliffs. These characteristics of seabird nesting sites dramatically limit the range of occurrence of ornithogenic soils, and the accompanying flora and fauna, to locations where talus-breeding species occur. As a result of climate

  14. L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

    International Nuclear Information System (INIS)

    The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ''Balanced Biological Community'' (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake

  15. Influence of mesoscale anticyclonic eddies on zooplankton distribution south of the western Aleutian Islands during summer

    Science.gov (United States)

    Saito, R.; Yamaguchi, A.; Yasuda, I.; Ueno, H.; Ishiyama, H.; Imai, I.

    2013-12-01

    Mesoscale anticyclonic eddies have been observed south of the Aleutian Islands located between the Bering Sea and the subarctic Pacific. Eddies farther east, in the Gulf of Alaska, are known to transport coastal water and coastal zooplankton to offshore open ocean. The impacts of mesoscale anticyclonic eddies formed south of the western Aleutian Islands (Aleutian eddies) on the zooplankton community are not fully understood. In the present study, we describe zooplankton population structures within an Aleutian eddy and outside the eddy during July 2010. Our field study was conducted at seven stations along 51°15‧N from 171°21‧E to 174°38‧E (western line) and at four stations along 50°40‧N from 176°24‧E to 178°44‧E (eastern line) on 7-8 July 2010. At each station, environmental data (temperature, salinity and fluorescence were measured by CTD/XCTD. Zooplankton samples were collected by vertical tow of 150 m depth to the surface using 100 μm mesh size plankton net. Based on the sea level anomaly (SLA), the western line crossed an anticyclonic eddy but the eastern line did not cross the eddy (Fig. 1). This Aleutian eddy was formed south of Attu Island (52°54‧N, 172°54‧E) in mid-February 2010, and it moved southeastward in the next five months. The SLA near the eddy center, representing the strength of the eddy, continuously increased, and the area oscillated at one to two month periods overlain on a general increase from ~7,000 to ~18,000 km2. Large oceanic copepods, Neocalanus cristatus, Eucalanus bungii and Metridia pacifica were more abundant inside the eddy than the outside. Inside the eddy, the life stage distribution of N. cristatus was advanced than that outside, and Neocalanus spp. had accumulated more lipids. These conditions probably reflect the greater primary production in the eddy, production enhanced by nutrients advected into the eddy. Since the Aleutian eddy was formed in offshore waters and/or eddy-eddy interaction occurred

  16. L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, J.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bowen, M. [Normandeau Associates, Inc., New Ellenton, SC (United States)

    1992-03-01

    The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ``Balanced Biological Community`` (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake.

  17. MULTIPLE STRESSOR EFFECTS OF HERBICIDE, PH, AND FOOD ON WETLAND ZOOPLANKTON AND A LARVAL AMPHIBIAN

    OpenAIRE

    Chen, Celia Y.; Hathaway, Kevin M.; Thompson, Dean G.; Folt, Carol L

    2007-01-01

    Interactions of herbicides and natural environmental stressors such as pH and food availability are poorly understood. We tested a chemical formulation of triclopyr (Release®) at environmentally relevant test concentrations (0.25 and 0.50 mg/L) in combination with two levels of pH (pH 5.5 and 7.5), and two levels of food availability (high and low). Population level effects of each stressor alone and in combination with the others were investigated using Simocephalus vetulus, a zooplankton sp...

  18. The barred grunt Conodon nobilis (Perciformes: Haemulidae) in shallow areas of a tropical bight: spatial and temporal distribution, body growth and diet

    Science.gov (United States)

    Pombo, Maíra; Denadai, Márcia Regina; Bessa, Eduardo; Santos, Flávia Borges; de Faria, Vanessa Hermann; Turra, Alexander

    2014-06-01

    This study aimed to comprehensively investigate the population biology of Conodon nobilis (Perciformes, Haemulidae) in Caraguatatuba Bight, southeastern Brazil. Monthly trawls were performed from October 2003 through October 2004 in two areas of the bight that are similar to but distant from each other, South and North. For all specimens, the size was measured and the sex and reproductive stage identified. Abundance and size were compared over areas and months. Body growth parameters were parameterized according to the Von Bertalanffy growth function. The stomach contents were identified and quantified. C. nobilis occurred mainly in the North area and showed an erratic pattern of abundance over time. Several cohorts entered in different periods, but very few large and mature individuals were observed. The results indicate a preference for shallow, ocean-influenced habitats and some degree of segregation between young and older individuals. The species showed a distribution consistent with an r-strategist species, with high abundance and a high growth constant ( K = 0.68 year-1 and L max = 34.2 cm). Both the relative length of the digestive tube and the prey items indicated a carnivorous feeding habit; mysids were the main item of the diet throughout the study period, indicating that this grunt is a specialist feeder. Other frequently observed items were amphipods and fish fragments. Ingestion of scales is possibly intentional.

  19. 228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

    NARCIS (Netherlands)

    Schmidt, C.; Hanfland, C.; Regnier, P.; Van Cappellen, P.; Schlüter, M.; Knauthe, U.; Stimac, I.; Geibert, W.

    2011-01-01

    Activities of the naturally occurring radium nuclides 228Ra, 226Ra, 224Ra and 223Ra were determined in waters of the open German Bight and adjacent nearshore areas in the North Sea, in order to explore the potential use of radium isotopes as natural tracers of land–ocean interaction in an environmen

  20. 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.