Distribution Of Zooplankton Communities Research Articles

Floods drive functional zooplankton diversity in a core area of the Brazilian Pantanal Biosphere Reserve

ABSTRACT Water dynamics in floodplains are fundamental in structuring aquatic communities. Our research investigated zooplankton communities in the Pantanal ecosystem. Different hydroperiod phases can influence the functioning of aquatic ecosystems, but an understanding of the taxonomic and functional diversity of zooplankton in these areas is lacking. Over 3 years (2018–2020), we assessed the zooplankton community in habitats along the Paraguay River at the Taiamã Ecological Station, considering the flood, ebb, drought, and inundation phases. We used indices such as Rao’s quadratic entropy (RaoQ), functional evenness (FEve), functional divergence (FDiv), community weighted means (CWM), and fourth-corner RLQ to investigate the potential relationships between the taxonomic and functional diversity of zooplankton and the hydroperiod phases and limnological variables. We identified 153 species of zooplankton, with greater richness in the families Lecanidae and Brachionidae (rotifers) and Chydoridae and Daphnidae (cladocerans). Species composition varied significantly between flood and drought phases. We observed positive relationships between chlorophyll a, total nitrogen/phosphorus, and species with larger body size, pelagic habitat, filter-feeding mode, and medium predator evasion capacity, whereas littoral species and those with low predator evasion capacity showed negative relationships. CWM exhibited differences in functional traits between hydroperiod phases. FDiv analysis indicated well-defined ecological functions among the community species, and the low FEve value during the flood phase indicated the dominance of certain functional attributes. These results emphasize the relationship between hydrological processes and the distribution of zooplankton communities, highlighting the importance of functional diversity in understanding ecological interactions.

EDNA of zooplankton reveals the ecological community thresholds for key environmental factors in the Baiyangdian Lake aquatic ecosystem

BackgroundThe drastic change in an ecosystem as a threshold phenomenon caused by abrupt changes in environmental conditions is a focus of current ecological research. However, the study of ecological thresholds has generally been limited to estimating the threshold values of single factors. Using eDNA metabarcoding technology, we collected zooplankton data from Baiyangdian Lake, the largest freshwater lake in the North China Plain, to explore the zooplankton community distribution characteristics and the relevant environmental factors. We used Threshold Indicator Taxa Analysis (TITAN) to determine the thresholds of key environmental factors and to identify the factors influencing biological diversity.ResultsBy comparing previous studies, we found that the zooplankton community composition based on eDNA metabarcoding was similar to that based on morphological methods, and that the data could be used to estimate ecological thresholds and assess risk conditions. Temperature (T), electrical conductivity (EC), and turbidity were the major environmental factors affecting the zooplankton community structure. The composition and structure of zooplankton communities in rivers and lakes were significantly different due to the influence of specific environmental factors. The results of TITAN analysis showed that there were different indicator species for T and EC in rivers and lakes. The protection thresholds of zooplankton in rivers were T = 19.0 °C and EC = 795 μS/cm, whereas the protection thresholds of zooplankton in lakes were T = 14.3 °C and EC = 1920 μS/cm. The overall values for the Baiyangdian watershed were T = 15.5 °C and EC = 1073 μS/cm. Compared with the field monitoring results, approximately 50% of the water quality index values at the sampling points in the Baiyangdian watershed exceeded the negative response threshold, indicating that Baiyangdian Lake was disturbed.ConclusionsThe validity of eDNA technology in biodiversity analysis was confirmed by the zooplankton community data from Baiyangdian Lake. The ecological thresholds derived by combining eDNA technology with Threshold Indicator Taxa Analysis (TITAN) are beneficial to the biological conservation of the region.

Spatial pattern analysis of zooplankton and surface water of pit lakes (Raniganj coal field, India)

ABSTRACT Open pit technique is often the simplest and most cost effective mining technology. Coal mining, which began in 1774 in Raniganj, West Bengal, India, led to many abandoned pits, which led to the formation of pit lakes. Mining has a tablvariety of environmental ramifications around the world. On the other hand, the pit lakes of the Raniganj coal field (RCF) are being used for recreational purposes. Knowledge of the spatial pattern in the zooplankton population and surface water quality in pit lakes waters of the Raniganj coal field region is rather limited. Sixteen pit lakes in the RCF in West Bengal, India, were investigated from January 2019 to December 2021. In the present study, we analyzed the spatial pattern and mode of distribution of zooplankton communities based on Coefficient of dispersion methods. To perform a comprehensive analysis of the water quality condition of this study area, we apply water quality index (WQI) methods. A total of 51 taxa were identified and the density was primarily dominated by rotifers. The most dominant species were: Brachionus forficula, Paracyclops sp. and Sida sp. Clumped type of zooplankton distribution pattern was observed in the studied pit lakes. The water quality in most of the studied pit lakes was poor. All the water quality parameters showed significant spatial variations as per Kruskal-Wallis test. The clustering technique produces three groups of pit lakes that are particularly convincing as the pit lakes in these groups showed comparable characteristics.

Latitudinal transition of epipelagic mesozooplankton in the northwestern Pacific in winter

The northwestern Pacific (NWP) is a hotspot of marine biodiversity study, and zooplankton is a crucial secondary producer in the marine ecosystem. It is of utmost importance to do extensive study on the distribution of zooplankton community in the NWP. The distribution of epipelagic zooplankton community in the 143–146°E section between the equator and 36°N in winter was examined in this study. The findings indicated that the Kuroshio extension, the North Pacific Subtropical Gyre, the North Equatorial Current and the North Equatorial Countercurrent were the four main ocean currents in the NWP that regulated the latitudinal transition of epipelagic mesozooplankton and split the sample section into four station groups. The key factors influencing zooplankton's geographic distribution were temperature, primary productivity, and current movement. In general, as latitude increased, zooplankton abundance and biomass first decreased and subsequently flourished in the NWP. Diversity indexes and indicator species also revealed the difference across the communities in four station groups. The body length of zooplankton declined gradually from north to south under the combined influence of temperature and primary production, with the minimum in the oligotrophic subtropical zone and a sub-peak in the high primary production area near the equator. Additionally, the abundance of zooplankton was higher in the winter than in the summer due to seasonal fluctuations in the properties of the ocean currents. This study elucidated the control effects of ocean currents on the latitudinal distribution of zooplankton, supplemented records of the geographic distribution and body length characteristics of zooplankton communities in the NWP, and provided the basis for further research on the ecological role of zooplankton communities and the global changes of marine ecosystems.

Chemical assessment of water quality, heavy metals, and the distribution of zooplankton communities, based on field and GIS data in the drains of Burullus Lake, Egypt

Chemical assessment of water quality, heavy metals, and the distribution of zooplankton communities, based on field and GIS data in the drains of Burullus Lake, Egypt

Structural Characteristics of Zooplankton and Phytoplankton Communities and Its Relationship with Environmental Factors in Different Regions of Nanhu Lake in Jiaxing City

Nanhu Lake is a red tourist attraction in Jiaxing city and the birthplace of the "Red Boat Spirit."To identify the influence of environmental factors on the distribution of plankton communities after ecological restoration in different regions, the environmental factors and plankton community in areas A, B, C, D, and S of Nanhu Lake were investigated in January 2021 after the completion of the ecological restoration projects. The concentrations of total nitrogen(TN), dissolved total nitrogen (DTN), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total phosphorus (TP), and dissolved total phosphorus (DTP) in the ecological restoration areas were significantly lower, and the content of dissolved oxygen (DO) was significantly higher (P<0.05) than those in the non-restoration area. The main phytoplankton species in the study area belonged to Cyanophyta and Bacillariophyta, and the main zooplankton species were protozoans and rotifers. The phytoplankton biomass in the restored area was lower than that in the unrestored area, and the number of phytoplankton and zooplankton species increased. Clustering and principal coordinate analysis results showed significant differences in plankton communities among the restoration areas (P<0.05), and plankton structures in regions A and B were similar. Redundancy analysis (RDA) showed that the main environmental factors affecting the distribution of phytoplankton communities were DO, NO3--N, pH, and water temperature (WT). The main driving factors of zooplankton community distribution were DO, NO3--N, NH4+-N, and TP. The results clarified the phytoplankton community characteristics and environmental correlation in different regions of Nanhu Lake, which can provide data support and reference for water ecological restoration of the lake.

Influence of some environmental factors on the distribution of zooplankton complexes in Mandra Reservoir, in Southeastern Bulgaria

The aim of the present study was to trace the influence of some environmental factors (w.temperature, wind, transparency, depth) on the distribution of zooplankton communities in the system Reservoir Mandra and the ecotone zones formed at the confluence of rivers Fakiyska, Sredetska, Izvorska and Rusokastrenska. Four samplings were performed at seven sites between February 2020 and January 2021. After determining the species composition and abundance, the results were subjected to structural analysis and Canonical Correspondence Analysis (CCA). A total of 67 taxa were identified, constituting about 48% of the Rotifera group, 27% of Cladocera and 19% of the Copepoda and only 6% from Protozoa. The Shannon-Weaver index for individual species diversity was between 2.37 and 0.62. The positive and negative correlation of zooplankton distribution in CCA shows that the relative abundance of any species depends on specific environmental variables. Analysis showed that temperature and wind had the strongest impact on the distribution of zooplankton.

Study of vertical distribution dynamics of zooplankton in a thermally stratified warm monomictic lake of Kashmir Himalaya

AbstractIn the present study, we investigated how stratification patterns and the related physico‐chemical characteristics impact the vertical distribution of zooplankton community during the two consecutive stratifications in a warm monomictic lake (Manasbal Lake) in the Ganderbal area of Central Kashmir. Two consecutive events of stratification and deepening of thermocline recorded during the sampling period led to significant changes in the vertical distribution of zooplankton community. Physico‐chemical characteristics displayed significant changes with the stratification pattern. Temperature of the surface water (0 m) increased gradually from 13°C to 29°C, resulting in a higher thermal gradient. pH and dissolved oxygen (O2) displayed clinograde curves with vertical depth. Keratella cochlearis and Polyarthra vulgaris (Rotifers) were most dominant in terms of density and abundance at the thermocline and significantly decreased at the hypolimnion. Cladocera with significant difference along the vertical column showed an epilimnetic distribution with Ceriodaphnia reticulata and Ceriodaphnia quadriangularis being the major contributors. Among copepods, Cyclops viridis was recorded at all depths in greater dominance. Acanthodiaptomus denticornis (Diaptomidae) showed higher abundance from epilimnion to thermocline but decreased at hypolimnion. The results showed that the strong vertical gradient of environmental factors occurs in the Manasbal lake. Among them, dissolved oxygen, water temperature, and nutrients controlled the zooplankton community with higher aggregation above the thermocline. Therefore, the present investigation regarding the dynamic patterns of zooplankton community along the vertical gradient in a stratified lake could be important in monitoring habitats and to understand the ecology of warm monomictic lakes.

Biogeography of the Southern Ocean: environmental factors driving mesoplankton distribution South of Africa.

Spatial distribution of zooplankton communities depends on numerous factors, especially temperature and salinity conditions (hydrological factor), sampled depth, chlorophyll concentration, and diel cycle. We analyzed and compared the impact of these factors on mesoplankton abundance, biodiversity, quantitative structure based on proportion of taxa and qualitative structure based on presence/absence of taxa in the Southern Ocean. Samples (43 stations, three vertical strata sampled at each station, 163 taxa identified) were collected with a Juday net along the SR02 transect in December 2009. Mesoplankton abundance in discrete vertical layers ranged from 0.2 to 13,743.6 ind. m−3, i.e., five orders of magnitude, maximal and minimal values were recorded in the upper mixed and in the deepest layer, respectively. Within the combined 300-m layer, abundances ranged from 16.0 to 1,455.0 ind. m−3, i.e., two orders of magnitude suggesting that integral samples provide little information about actual variations of mesoplankton abundances. A set of analyses showed that depth was the major driver of mesoplankton distribution (abundance, biodiversity, quantitative structure), hydrological factors influenced two of them (quantitative and qualitative structure), chlorophyll concentration strongly affected only quantitative structure, and diel cycle had an insignificant effect on mesoplankton distribution. Using our current knowledge of the fine structure of the Antarctic Circumpolar Current, we compared effects of four hydrological fronts, i.e., boundaries between different water-masses with distinct environmental characteristics, and eight dynamic jets (narrow yet very intense currents) on mesoplankton distribution. Subtropical, Polar, and Subantarctic Fronts drove quantitative and qualitative structure of mesoplankton assemblages (decreasing in order of influence), while the Southern Boundary affected only qualitative structure. Effects of dynamic jets were insignificant. We suggest that mesoplankton composition is driven by hydrological parameters and further maintained through compartmentalization by fronts. Impact of local eddies and meanders on biodiversity, abundance, qualitative and quantitative structure of mesoplankton is comparable to that of hydrological fronts. Qualitative structure of mesoplankton assemblages mirrors hydrological structure of the Southern Ocean better than quantitative structure and may be recommended for biogeographic analyses of the Southern Ocean. Comparisons with previous reports from the same area retrieved no significant changes in mesoplankton distribution during the period 1992–2009.

Abundance and distribution of zooplankton communities inhabiting the intertidal zone of the Suez Gulf, Red Sea, Egypt

Zooplankton communities at the Gulf of Suez were investigated during the current study and their abundance was correlated with the physicochemical parameters of the area. The goal of the study was to estimate the distribution and abundance of zooplankton taxa under various habitat stressors and update the ecological database of the study area. The study recorded 39 species of zooplankton in 16 taxa with a total abundance of 66300 organisms across all investigated sites. The organisms were distributed between holoplankton that recorded approximately 55560 organisms (84.2 %) and meroplankton which recorded approximately 10740 organisms (15.8 %). The most abundant groups were Copepoda 52340 organisms (78.9 %), larval stages (11%) and Maxillopoda (3 %). While, Anthomedusea, Leptomeduea, and Pteropods were rarely recorded. Among the surveyed sites, Zafarana recorded the highest abundance (23537 Organisms) with a percentage of 63 of the total zooplankton populations, whereas the lowest site in abundance was Port-Tewfik which recorded (6656 organisms), represented a percentage of 10 % of the total populations. The current work showed that copepods recorded a significant difference in spatial distribution, while copepods, dissolved oxygen, water temperature, and total dissolved solids differed significantly at temporal distribution.

ABUNDANCE OF RELATED SPECIES, &lt;i&gt;KELLICOTTIA BOSTONIENSIS&lt;/i&gt; (ROUSSELET, 1908) AND &lt;i&gt;K. LONGISPINA&lt;/i&gt; (KELLICOTT, 1879) (ROTIFERA: BRACHIONIDAE), IN THE COMMUNITIES OF ZOOPLANKTON OF THE PUSTYNSKAYA LAKE-RIVER SYSTEM (NIZHNY NOVGOROD OBLAST)

The article presents the features of the spatial distribution of zooplankton communities in the water area of the Pustynskaya lake-river system. The abundance of two related species of the genus Kellicottia , the alien Kellicottia bostoniensis (Rousselet, 1908) and the indigenous K. longispina (Kellicott, 1879), was analyzed in dedicated communities in 2013-2017. The greatest abundance of the alien species was noted in zooplanktocenoses of mesotrophic water bodies (the Serezha River and Lake Svyato). It was found that after the period of mass development of K. bostoniensis in 2013-2014, which might be due to the initial stage of naturalization of the alien species, its abundance had sharply decreased. In 2013-2014 the abundance of the indigenous species K. longispina (Kellicott, 1879) was significantly lower than that of the alien species. Rotifer K. longispina dominated in the Protoka and Lake Svyato in 2017. The highest density of both species was found in the metalimnion of the mesotrophic Lake Svyato. A statistically significant positive correlation was found between the abundance of K. bostoniensis and the temperature, transparency, and pH of water, as well as the abundance of predatory zooplankton species. The abundance of the native species K. longispina correlated negatively only with the value of water pH.

Western Pacific Zooplankton Community along Latitudinal and Equatorial Transects in Autumn 2017 (Northern Hemisphere)

During the autumn of 2017, a study was conducted to assess the zooplankton community composition in three sections (two latitudinal, going from Japan to the equator, and one longitudinal on the equator) of the Western Pacific Ocean. A total of 384 species of zooplankton adults and 21 groups of zooplankton larvae were identified, with copepods being the predominant taxon. The common dominant species across the three sections were Acrocalanus gibber, Canthocalanus pauper, Oithona similis, Paracalanus aculeatus, and Oncaea venusta. Zooplankton abundance was the highest in the equator section, with a mean abundance of 258.94 ± 52.57 ind./m3. Comparatively, a low abundance was recovered from the Subtropical Countercurrent (STCC) region, while the highest abundance holding stations were located in the eastern equatorial and North Equatorial Countercurrent (NECC) regions. Pearson’s correlation, canonical correspondence analysis, and other methods were used to analyze the relationship between environmental factors and zooplankton. We found that the Shannon–Wiener diversity index and Pielou’s uniformity index were significantly correlated (p &lt; 0.05) with concentrations of nitrite and chlorophyll a. The distribution of zooplankton was also limited by nutrients, chlorophyll a, and dissolved oxygen. In addition, we reveal differences in the abundance of species in the equatorial and latitudinal seas. We found that not only temperature and nutrient salinity, but also ocean currents and the movement of water masses, influence the distribution of zooplankton communities in the Western Pacific.

Correlation between seasonal physicochemical parameters and zooplankton diversity in Asejire reservoir, Southwest Nigeria

Occurrence and distribution of zooplankton community in Asejire reservoir was carried out between April 2017 and March 2018 to ascertain the critical association between zooplankton and physicochemical parameters of the water. A total of 130 taxa were recorded comprising of six taxonomic groups (Rotifera, Copepoda, Cladocera, Protozoa, Ostracoda and Insecta). The zooplankton in the reservoir follows a sequence as Rotifera > Copepoda > Cladocera > Protozoa > Ostracoda > Insecta. Zooplankton abundance was higher in the rainy season compared to the dry season. Correlation was drawn between the different physicochemical parameters and zooplankton occurrence. Zooplankton population showed a positive correlation with conductivity, transparency, total dissolved solids, dissolved oxygen and sulphate, whereas negative correlation with pH, temperature, turbidity, biological oxygen demand, phosphate, nitrate and chloride. Observed changes in the zooplankton community structure were related to seasonal fluctuations in water conductivity, pH, transparency, total dissolved solids and turbidity of the water. Elevated levels in water transparency, dissolved oxygen and nutrients such as phosphate indicate favorable conditions for the growth of zooplankton. Turbidity, biological oxygen demand and increased pH has a negative effect on the zooplankton abundance.

Distribution of zooplankton community in Toli shad (Tenualosa toli) habitats, Sarawak, Malaysia

Abstract. Aiman WM, Yusoff FM, Arshad A, Kamal AHM, Ismail J, Idris MH, Karim NU, Asif AA. 2020. Distribution of zooplankton community in Toli shad (Tenualosa toli) habitats, Sarawak, Malaysia. Biodiversitas 21: 4022-4033. The river ecosystems of Sarawak has been identified as important-spawning ground for economically important Toli shad (Tenualosa toli) fisheries. In these river ecosystems, zooplankton serves as a secondary producer to the different types of fish larvae including Toli shad. The productivity and biomass of zooplankton are important factors to control the production of higher trophic level organisms like fish larvae and fishes in different stages including T. toli larvae. In this viewpoint, the composition and abundance of zooplankton were investigated at 5 (five) sampling stations (considered to be spawning and nursing areas of Toli shad) at Batang Lupar and Batang Sadong estuaries from July 2016 to June 2017. A total of 29 zooplankton taxa were recorded that belong to 14 major groups comprised of Copepoda (Arthropoda), Crustacean nauplii (Arthropoda), Fish larvae (Chordata), Mollusca (Mollusca), Luciferidae (Arthropoda), Cnidaria (Cnidaria), Ostracoda (Arthropoda), Cirripedia (Arthropoda), Polychaete larvae (Annelida), Chaetognatha (Chaetognatha), Appendicularia (Chordata), Amphipoda (Arthropoda), Echinodermata larvae (Echinodermata) and Cladoceran (Arthropoda). Copepod was dominant group of zooplankton (82.40-94.41%) at all stations, contributing 477.37-25921.89 ind/m3 and 88.38% of total abundance. The second highest was crustacean larvae (2.45-9.38%) in all stations, contributing 0-2391.7 ind/m3 and 5.88% of total abundance. Zooplankton abundance was higher at downstream station 1 (8460.72 ind/m³) followed by station 2 (5479.80 indi/m³), station 3 (4571.95 ind/m³), station 4 (4394.20 ind/m³) and upstream station 5 (4156.73 ind/m³). Canonical Correspondence Analysis showed that the abundance of copepods was highly influenced by total turbidity and nitrate in the riverine and estuarine ecosystems. Abundance of zooplankton was relatively higher (9549.31 ind/m³) during the post-monsoon and lower (3534.56 ind/m³) during the southwest monsoon.

Review of spatial and inter-annual changes in the zooplankton community structure in the western Arctic Ocean during summers of 2008–2017

Reduction in summer sea ice coverage has recently been observed in the western Arctic Ocean. Changes in the coverage and timing of sea ice retreat are expected to have a great impact on the marine ecosystem. In this study, we evaluated inter-annual changes in the spatial distribution of zooplankton communities in the western Arctic Ocean, during the summers of 2008, 2010, 2012–2017. A total of 339 casts were conducted to collect zooplankton by vertical hauls at 22–63 stations per year in the western Arctic Ocean, between August 26 and October 13, 2008, 2010, 2012–2017. Based on cluster analysis, four zooplankton communities (basin, slope, shelf, and new-shelf) were identified. Horizontal distribution of the zooplankton communities corresponded with the depth of the sea floor. No significant interannual variability in zooplankton and copepod abundance was observed in the Canada basin; however, a decline in the abundance of dominant copepods associated with an enhanced freshening of seawater was suggested by a General Linear Model analysis. The shelf assemblage was characterized by a high abundance of Pacific species that was predicted by the length of the open water period. The new-shelf assemblage, located between the shelf and the slope, showed low species diversity and abundance and was observed only in 2012, 2015, 2016 and 2017 when the melting day of sea ice was significantly earlier than in the other years. Our study indicates that different changes in each region can be expected in response to the possible environmental changes in the Pacific Arctic.

Variability and spatial distribution of zooplankton communities in the western Chukchi Sea during early fall

The western Chukchi Sea ecosystems are among the most productive systems in waters of the Russian sector of the Arctic. Chukchi Sea is of exceptional interest not only for the assessment of biological resources, but also for the analysis of quantitative distribution of key species in the study of long-term zooplankton fluctuations under the effect of various natural and anthropogenic factors. In this study, we compared the zooplankton composition, abundance, biomass, and spatial distribution in relationship with water characteristics on the western Chukchi Sea shelf. The community was dominated in number by copepods of the genera Pseudocalanus, Oithona, Microsetella, and bivalve larvae; in biomass, it was dominated by the copepod Calanus glacialis. The highest abundance and biomass of zooplankton were observed at the stations with the cold Winter Water and Melt Water. The zooplankton communities in the eastern corner of the Herald Canyon were influenced by the Anadyr/Bering Sea Water; in contrast, the zooplankton in the western corner of the Herald Canyon was more similar to the communities of the shallow Arctic seas. The trend of changes in the Chukchi Sea zooplankton community structure towards the predominance of small-sized crustacean species and their southward expansion along the southwestern Chukchi shelf are discussed.

Distribution of Zooplankton Community in the River Nile at Esna Barrages, Egypt in relation to some ecological factors

In riverine systems, zooplankton communities are usually thought to be driven by abiotic forces. This study was designed to assess the effect of ecological factors on the distribution of zooplankton community in the River Nile at Esna barrages which located 1.2 km downstream the old barrages. Monthly samples were collected during a period of one year from six sites situated in the River Nile, (upstream and downstream) of Esna Barrages. Seven physic-chemical parameters were measured during sampling using electronic portable instruments: air and water temperature, hydrogen ion concentration, dissolved oxygen, conductivity, total dissolved solids and turbidity. The collected zooplankton groups were Cladocera, Copepoda and Ostracoda where Cladocera exhibited the highest peak of density. The highest value of total abundance of zooplankton was recorded during winter 40% and the lowest value was recorded during summer 11%. The results indicated that Turbidity, pH and conductivity were the most affecting factors on abundance of all zooplankton groups during the study. Cladocera group correlated significantly with dissolved oxygen (p>0.01) and pH (p<0.01). Moreover, temperature and turbidity were the most affecting factors on Copepoda, while Ostracoda was affected by pH and conductivity.

Temporal distribution of zooplankton communities in coastal waters of the northern Bay of Bengal, Bangladesh

The temporal distribution pattern of zooplankton communities was studied in coastal waters of the northern Bay of Bengal, Bangladesh, during a 1-year period of investigation (May 2014-April 2015). Throughout the investigation, a total of 38 zooplankton species were recorded, in details 22 holo-plankton and 16 mero-plankton species. Copepods (Acartia danae, Acartia tonsa, Cyclops biscuspidatus, and Canthocalanus pauper), amphipods (Grandidierella megnae), shrimps (Penaeus indicus and Penaeus merguiensis), Acetes (Acetes indicus), and mysids (Americamysis bahai) were the dominant zooplankton taxa. The maximum abundance of total zooplankton and species richness was recorded in monsoon season whereas abundance of holo-plankton and species diversity was recorded in winter. Multivariate analyses revealed that the temporal pattern of species distribution of zooplankton communities significantly differed among the four seasons. RELATE analysis signified that temporal variation in species distribution and community structure of zooplankton significantly correlated with ecological condition of water. Moreover, BEST matching analysis indicated that NO2-N along with salinity, rainfall, transparency, TDS, TSS and pH were the main driving forces for these temporal variations in species distribution and community composition of zooplankton communities. Finally, correlation analysis showed that species evenness and diversity significantly correlated with salinity, transparency and TDS. These results suggest that zooplankton distribution pattern might be shaped by ecological condition of water in such marine ecosystem and may potentially be used as bioindicators of marine water quality.

Zooplankton communities in the Drake Passage through environmental boundaries: a snapshot of 2010, early spring.

BackgroundSpatial distribution of zooplankton communities influenced by various environmental factors is always important for understanding pelagic ecosystems. The area of the Drake Passage (Southern Ocean) is of particular interest owing to the high spatial and temporal variability of hydrological parameters affecting marine fauna. This study provides a survey of zooplankton composition and spatial distribution along a transect in the Drake Passage sampled during the 31th Cruise of RV “Akademik Sergey Vavilov” in November, 2010. The main aim was to trace the main regularities in spatial zooplankton structure and its relationships with the environmental parameters.MethodologyA total of 43 vertical hauls from the surface to 1,000 m depth were made at 13 stations using the Juday plankton net. 60 taxa were recorded, abundance and biomass of each were assessed. Environmental parameters including temperature, salinity, depth, horizontal distance between stations and surface chlorophyll concentration were tested as environmental factors possibly explaining plankton distribution.ResultsHigher zooplankton abundance and biomass with lower diversity were observed near the Polar Front. Cluster analysis revealed five different groups of zooplankton samples, four of which were arranged mostly by depth. Along the transect within the 1,000 m depth range, the qualitative taxonomical composition differed significantly with depth and to some extent differed also among horizontal hydrological regimes, while the quantitative structure of the communities (abundance of taxa) was mainly determined by depth. Plankton assemblages within the upper 300-m layer depended on hydrological fronts. Abundance of dominant taxa as well as total zooplankton abundance showed a clear correlation with depth, salinity and surface chlorophyll concentration. Some taxa also showed correlations with temperature and latitude. Between the stations the similarity in zooplankton structure was clearly dependent on the distance among them which indicates an importance of latitudinal gradient. Surface chlorophyll concentration was not correlated with zooplankton biomass, which can be explained by the uncompleted seasonal migrations of zooplankton from deeper waters in early spring.

Community structure of zooplankton across environmental variables in a high-altitude lake of central Himalayas, India

ABSTRACTWe determined seasonal and spatial variation of zooplankton and their correlation with environment variables in a subtropical lake of the Himalayas. Thirty-eight species of zooplankton were identified, of which, 38.0% belonged to rotifera, 26.3% to cladocera, and 15.7% to copepoda. Nitrogen nutrients, total organic matter (TOM), and clay particles significantly influenced on the distribution pattern of zooplankton. Non-metric multidimensional scaling analysis showed homogeneous assemblages of dominant zooplankton species except Chydorus gibbus which has wider range of niche partitioning. Turbidity formed by suspended materials facilitated better avoidance of larger zooplankton like Daphnia similis from predators. Sedimentary silt particles influenced on the assemblages of sensitive species such as Tropocyclops prasinus, Asplanchna priodonta and Colurella obtuse. Changes within the land-use pattern in the catchment of the central Himalayan lakes either directly or indirectly impact on the distribution of zooplankton community.