Seasonal Variation of Zooplankton Communities and the Effects of Environmental Factors in the Seawater Near Taishan Nuclear Power Station

In the seawater near Taishan Nuclear Power Station, Zooplankton community composition and abundance, the biomass of major taxa, vertical distribution pattern, together with several environmental factors were investigated to evaluate the variation tendency as the seasons change. The structure characteristics of the zooplankton community were analyzed by Margalef species richness (d), Shannon-wiener species diversity index (H’), Pielou evenness index(J’), zooplankton dominant (Y), and dominant species replacement rate (R). There are 48 species within 11 classes of zooplankton identified, including 32 species of copepods. Zooplankton species richness changed obviously in the four seasons, Spring saw the highest (8010.00 ind.m-3), followed by winter (5100.00 ind.m-3), autumn (1713.75 ind.m-3), and summer (1196.25 ind.m-3). Similar trends were observed for the wet biomass, which was highest in spring (215.90 mg.m-3), followed by winter (181.70 mg.m-3), summer (78.56 mg.m-3), and autumn (24.69 mg.m-3), which gave an annual average of 125.21 mg.m-3. The results indicate that the abundance and biomass in spring were significantly higher than those in other seasons. Altogether 8 dominant species were identified along the whole year: Acrocalanmus gibber, Bestiolina amoyensis, Paracalanus parvus, Acartia danae, Mesocyclops leuckarti, Noctiluca scientillans, Penilla avirostris, and Lucifer penicilliger. The annual average Shannon-Wiener diversity index, Margalef diversity index, Pielou evenness index were 1.75, 1.83, and 0.74, respectively. The effects of environmental factors on the zooplankton community were studied by R and canonical correspondence analysis (CCA). According to Pearson correlation analysis and canonical correspondence analysis, the most important environmental factors influencing the changes of zooplankton species composition, abundance and distribution were water temperature, salinity, and pH in the whole year.

Ecological Assessment of Fish Culture Water Bodies Around Dhaka City, Bangladesh

This study was conducted during the period November, 2014 - June, 2015 in two urban fish culture pond, at Kalshi and Namapara area of Dhaka city. These ponds are connected to Baunia canal. Water samples were collected seasonally for water quality and zooplankton analyses. Except DO all other measured water quality parameters (pH, TDS, TSS, total ammonia-N, total nitrite-N, total nitrate-N, total phosphate, total sulphate, alkalinity and hardness) were found higher in water. A total of 10 heavy metals (Zn, Fe, Pb, Cd, Al, As, Cu, Na, Mn and Cr) were measured for determining its concentrations in waters in two seasons. A total of 10 zooplankton species were recorded at Kalshi during the study period and on an average, the density of zooplankton in dry season and in wet season were estimated to be 1386 indiv./L and 244 indiv./L respectively. On the other hand, a total of 19 zooplankton species were identified from Namapara water body and on an average, the density of zooplankton in dry season and in wet season were estimated to be 1760 indiv/L and 343 indiv./L respectively. Bacteriological analysis included the total plate count (TPC), total coliform (TC) and total faecal coliform (TFC) counts in waters, both in wet and dry seasons. In general, water qualities of the studied fish culture water bodies are highly deviated from the permissible standard levels of Environment conservation rules, 1997 and unsuitable for fish culture from fish health point of view. The measured high levels of metals in waters are likely to bioaccumulate in fish body. High abundance of bacterial flora in fish culture waters is also likely to be associated with fish health and may cause enteric diseases. Therefore, fish culture in these urban water bodies is likely pose potential health risks for human through consuming these fishes. Bangladesh J. Zool. 49 (2): 267-276, 2021

Trophic Interactions Promoting Dominance by Cyanobacteria in a Freshwater Pelagic Food Web

<p>Cyanobacterial blooms have occurred in the Lower Karori Reservoir (Wellington) for approximately the last eight years. The dominant species in the past have been identified as Anabaena lemmermannii and A. circinalis. The reservoir was built in 1874 as part of the first water supply scheme for Wellington City and has been closed to the public since 1906. The catchment was created into a "predator-free" native wildlife sanctuary in 1999. The first severe bloom in the Lower Karori Reservoir occurred during the summer of 2000/01. The objectives of this study were: - To establish a baseline knowledge of the food web within the Lower Karori Reservoir. - To follow the chemical and biological dynamics of the Lower Karori Reservoir for an extended period of time to observe seasonal changes associated with the cyanobacterial blooms. - To experimentally manipulate the trophic levels of the food web to determine which factors (i.e. resources or consumers) were most significant in promoting the growth of cyanobacteria. I sampled temperature, dissolved oxygen, nutrient levels, and phytoplankton and zooplankton communities from 7 October 2003 to 7 July 2004. I also monitored the diet of the zooplanktivorous fish (perch, Perca fluviatilis) present in the lake. The dominant cyanobacteria species was found to be A. lemmermannii. Three other cyanobacteria species were present during the study at low abundances, including A. planktonica which had not been previously recorded in the reservoir. The bloom of cyanobacteria was associated with thermal stratification. Nutrient concentrations were at moderate levels, characteristic of mesotrophic lakes. The perch population consisted mostly of smallsized individuals that feed predominately on large species of zooplankton that were at low abundances within the lake. During March 2004, I conducted a food web manipulation experiment within the Lower Karori Reservoir. I sought to test the role of nutrient resources (bottom-up) versus cascading effects of zooplanktivorous perch (Perca fluviatilis) (top-down) in controlling cyanobacteria in this lake. Experimental treatments with perch had higher levels of cyanobacterial densities, lower zooplankton species diversity and zooplankton species were generally smaller-sized than in treatments without perch. Nutrient treatments were not favourable for cyanobacteria as the addition of nitrogen probably meant that nitrogen fixing Anabaena species lost competitive advantage over other phytoplankton taxa. It is not known by which mechanism perch promoted cyanobacterial growth since this was not directly measured. Plankton community composition was altered by all treatments. This study indicates that blooms of Anabaena species in the Lower Karori Reservoir are the result of a number of complex interactions within the lake food web. Low nitrogen levels favour dominance by the nitrogen fixing cyanobacteria, which bloom during thermal stratification as they are able to maintain their position in the water column due to buoyancy control. Predation pressure by perch is likely keeping large filter-feeding zooplankton at low levels and thus reducing grazing pressure on phytoplankton. Phosphorus excretion by perch also probably favours cyanobacteria. An eradication of perch within the Lower Karori Reservoir would probably contribute to prevent cyanobacteria predominance. The removal of perch from the reservoir should be reasonably simple due its small size and contained area. Other methods which may help reduce cyanobacterial blooms within the reservoir include artificial mixing to prevent stratification. However, these methods can be expensive to install and run.</p>

Trophic Interactions Promoting Dominance by Cyanobacteria in a Freshwater Pelagic Food Web

<p>Cyanobacterial blooms have occurred in the Lower Karori Reservoir (Wellington) for approximately the last eight years. The dominant species in the past have been identified as Anabaena lemmermannii and A. circinalis. The reservoir was built in 1874 as part of the first water supply scheme for Wellington City and has been closed to the public since 1906. The catchment was created into a "predator-free" native wildlife sanctuary in 1999. The first severe bloom in the Lower Karori Reservoir occurred during the summer of 2000/01. The objectives of this study were: - To establish a baseline knowledge of the food web within the Lower Karori Reservoir. - To follow the chemical and biological dynamics of the Lower Karori Reservoir for an extended period of time to observe seasonal changes associated with the cyanobacterial blooms. - To experimentally manipulate the trophic levels of the food web to determine which factors (i.e. resources or consumers) were most significant in promoting the growth of cyanobacteria. I sampled temperature, dissolved oxygen, nutrient levels, and phytoplankton and zooplankton communities from 7 October 2003 to 7 July 2004. I also monitored the diet of the zooplanktivorous fish (perch, Perca fluviatilis) present in the lake. The dominant cyanobacteria species was found to be A. lemmermannii. Three other cyanobacteria species were present during the study at low abundances, including A. planktonica which had not been previously recorded in the reservoir. The bloom of cyanobacteria was associated with thermal stratification. Nutrient concentrations were at moderate levels, characteristic of mesotrophic lakes. The perch population consisted mostly of smallsized individuals that feed predominately on large species of zooplankton that were at low abundances within the lake. During March 2004, I conducted a food web manipulation experiment within the Lower Karori Reservoir. I sought to test the role of nutrient resources (bottom-up) versus cascading effects of zooplanktivorous perch (Perca fluviatilis) (top-down) in controlling cyanobacteria in this lake. Experimental treatments with perch had higher levels of cyanobacterial densities, lower zooplankton species diversity and zooplankton species were generally smaller-sized than in treatments without perch. Nutrient treatments were not favourable for cyanobacteria as the addition of nitrogen probably meant that nitrogen fixing Anabaena species lost competitive advantage over other phytoplankton taxa. It is not known by which mechanism perch promoted cyanobacterial growth since this was not directly measured. Plankton community composition was altered by all treatments. This study indicates that blooms of Anabaena species in the Lower Karori Reservoir are the result of a number of complex interactions within the lake food web. Low nitrogen levels favour dominance by the nitrogen fixing cyanobacteria, which bloom during thermal stratification as they are able to maintain their position in the water column due to buoyancy control. Predation pressure by perch is likely keeping large filter-feeding zooplankton at low levels and thus reducing grazing pressure on phytoplankton. Phosphorus excretion by perch also probably favours cyanobacteria. An eradication of perch within the Lower Karori Reservoir would probably contribute to prevent cyanobacteria predominance. The removal of perch from the reservoir should be reasonably simple due its small size and contained area. Other methods which may help reduce cyanobacterial blooms within the reservoir include artificial mixing to prevent stratification. However, these methods can be expensive to install and run.</p>

Distribution and species composition of zooplankton (rotifers and crustaceans) in the Basin of the Middle Volga River, Russia

The presented dataset contains information on the distribution and species composition of zooplankton (rotifers and crustaceans) registered in the Basin of the Middle Volga River, Russia. The studies have been performed in the Kuibyshev Reservoir (Samara Oblast and the Republic of Tatarstan), the Saratov Reservoir (Samara Oblast), in several lakes (Raifskoe, Gniloe, Krugloe and Lenevo) in the Volzhsko-Kamsky State Biosphere Reserve (Republic of Tatarstan) and in Lake Aslikul, one of the largest lakes of the Middle Volga River Basin, located in the Asly-Kul Natural Park (Republic of Bashkortostan). The hydrobiological data were obtained and published from 1957 to 2020. In total, the dataset includes 5141 records of 111 zooplankton species (including 17 subspecies), belonging to 45 genera. These are mainly native species - 98.5%, while the naturalised, including invasive species, accounts for less than 1.5%. A total of 5141 records have been published on the taxonomic diversity and occurrence of zooplankton (rotifers and crustaceans) in the Middle Volga River Basin. Each record includes information about the place and date of finding the specimen, its taxonomy, occurrence and abundance and the collector. If the information about the find has been published, a link to the corresponding reference is provided. The presented dataset supplements the data on the distribution of zooplankton species in the European part of Russia. Data on zooplankton in the Middle Volga River Basin are published for the first time.

Seasonal dynamics of zooplankton in lakes of different trophic status

In the article, we present the data about the dominant complexes of zooplankton species in the pelagic zone of lakes Naroch, Myastro, Batorino (2014 –2019), Malye and Bolshie Shvakshty (2014 –2015), Svir (2018). The seasonal dynamics of zooplankton is analysed. The contribution of taxonomic groups and individual species in the abundance and biomass of zooplankton in lakes with different trophic status is studied. We noted two peaks in the seasonal dynamics of zooplankton. Rotifers prevailed in the spring, while Crustacea dominated in the summer-autumn period. The relative biomass of cladocerans increased and the proportion of copepods decreased with the increasing of trophic status of the lakes.

Species diversity of phyto- and zooplankton in the water bodies of Kharanorskaya State District Power Plant, Transbaikalia (according to 2019 data)

We described the taxonomic structure of planktonic associations in the water bodies of Kharanor State District Power Plant (cooling pond, water supply, drainage, and water intake channels of Kharanor reservoir located in the arid zone of the south-eastern Transbaikalia in a highly continental climate). Hydrobiological researches were conducted in April, July, and October 2019. We identified 141 algal taxa ranked below the genus, representing the divisions of Cyanobacteria (15 taxa), Bacillariophyta (41), Chrysophyta (10), Cryptophyta (3), Dinophyta (4), Charophyta (8), Chlorophyta (56), and Euglenophyta (4), and 52 zooplankton taxa, including 28 species and subspecies of Rotifera, 15 species of Cladocera, and 9 species of Copepoda. In the cooling reservoir, the plankton community included 135 phytoplankton taxa and 38 zooplankton species; 58 algal taxa and 27 invertebrate species were sampled in the water supply channel, 50 taxa and 26 species were sampled in the drainage channel, and 94 taxa and 24 species were collected from water intake channel respectively. Six diatom species (Stephanodiscus hantzschii, Nitzschia sigmoidea, Fragilaria radians, Asterionella formosa, Ulnaria ulna) and four zooplankton species (rotifers Asplanchna priodonta and crustaceans Daphnia galeata, Bosmina longirostris, Thermocyclops crassus) occurred in all water bodies during the entire study period.

Hydrodynamics Regulate Longitudinal Plankton Community Structure in an Alpine Cascade Reservoir System

Previous studies report significant changes on biotic communities caused by cascade reservoir construction. However, factors regulating the spatial–temporal plankton patterns in alpine cascade reservoir systems have not been fully explored. The current study explored effects of environmental factors on the longitudinal plankton patterns, through a 5-year-long study on the environmental factors and communities of phytoplankton and zooplankton in an alpine cascade reservoir system located upstream of Yellow River region. The findings showed that phytoplankton and zooplankton species numbers in the studied cascade reservoir system were mainly regulated by the hydrological regime, whereas nutrient conditions did not significantly affect the number of species. Abundance and biovolume of phytoplankton in cascade reservoirs were modulated by the hydrological regime and nutrient conditions. The drainage rate, N:P ratio, and sediment content in cascade reservoirs were negatively correlated with abundance and biovolume of phytoplankton. Abundance and biovolume of zooplankton were not significantly correlated with the hydrological regime but showed a strong positive correlation with nutrient conditions in cascade reservoirs. Shannon–Wiener index (H’) and the Pielou index (J) of phytoplankton were mainly regulated by the hydrological regime factors, such as drainage rate and sediment content in cascade reservoirs. However, temperature and nutrient conditions were the main factors that regulated the Shannon–Wiener index (H’) and the Pielou index (J) of zooplankton. Species number, abundance, and biovolume of phytoplankton showed a significant positive correlation with those of zooplankton. Hydrodynamics and nutrient conditions contributed differently in regulating community structure of phytoplankton or zooplankton. These findings provide an understanding of factors that modulate longitudinal plankton community patterns in cascade reservoir systems.

Responses of Freshwater Zooplankton as Biological Indicators to the Aquatic Chemical Properties

Zooplankton are found very sensitive to even slight aquatic pollution due to a number of chemical imbalances in freshwater bodies. As an amazing tiny creature zooplankton play a very crucial role in the aquatic food chain by transferring energy from primary levels to tertiary organisms. For many years it has been well established that zooplankton act as promising biological indicators to continuously fluctuating aquatic environments and subsequently to global warming. While reacting to these aquatic environmental fluctu-ations, zooplankton population growth can either be stimulated or inhibited. The presence or absence of particular zooplankton species can reveal the trophic status of the water body. Moreover, in a harsh env-ironment, algal toxins may have drastic effects on the behavioral characteristics of zooplankton.

Seasonal Composition and Diversity of Zooplankton in Pichavaram Mangrove Forest, Southeast Coast of India

In the present study, the zooplankton diversity and distribution was studied in relation to seasonal variation of environmental parameters in the Pichavaram mangrove forest. Samples were seasonally collected (i.e., post-monsoon: January-2018 and monsoon: December-2018) from seven stations. A total of 48 zooplankton species belonging to two groups macro-zooplankton and micro-zooplankton were recorded during this study. A total of 48 species of zooplankton belonging to different groups were identified. Copepod was found to be the most dominant group and it contributed more than 50% of the total zooplankton collected in this study. The maximum number of zooplankton species (35) and diversity value (H’) 3.867 was recorded in the stations near coastal zone (P-7) during summer and minimum species number (24) and maximum species richness (d) 7.652 was recorded in stations near to freshwater zone (P-2) during monsoon. The species evenness (J') 0.866 was also recorded maximum at stations near river mouth (P-7). BIO-ENV (Biota-Environmental matching) and CCA results confirmed that the environmental parameters such as Temperature, Salinity, Dissolved Oxygen, Silicate, Chlorophyll, Primary Productivity, Total Biomass and Phaeopigments as the most influencing environmental parameters, which regulates zooplankton assemblage. The results of present study help to develop an understanding on the zooplankton distribution in mangrove forests, which will form a reliable tool in bio-monitoring studies