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

BackgroundIn reservoirs, zooplankton strongly interact with the physical and chemical characteristics of water, and this interaction is mainly influenced by climate variation and the different methods used to manage the dam water level. Therefore, the aim of this study was to evaluate how the distinct operating modes of two cascade reservoirs affected the richness, abundance, and composition of zooplankton, both spatially (intra and inter-reservoirs) and temporally (annual and seasonal). In this study, the upstream reservoir (Salto Santiago) operates using the storage method, with a water retention time (WRT) of 51 days, whereas the downstream reservoir (Salto Osório) operates using the run-of-river method, with a WRT of 16 days.MethodsZooplankton samples were collected for 16 consecutive years from the two reservoirs located on the Iguaçu River, Brazil. A total of 720 samples were collected. Four-way ANOVAs were used to determine the differences in richness and abundance of the zooplankton among years, periods, reservoirs, and environments. Multidimensional non-metric scaling (NMDS) and an analysis of similarities (ANOSIM) were used to describe similarity patterns in species composition. Finally, a canonical correspondence analysis (CCA) was used to select the environmental predictors that best explained the variation in zooplankton abundance data.ResultsWe identified a total of 115 taxa in this study, and rotifers were the richest group. In contrast, the copepods were the most abundant. The four-way ANOVA results showed significant differences in the species richness and abundance of the zooplankton among years, periods, reservoirs, and environments. The NMDS ordination and ANOSIM test indicated that the largest differences in zooplankton species composition were annual and seasonal differences. Finally, the CCA showed that these differences were mainly associated with changes in water transparency, temperature, and the chlorophyll a, phosphorus, and total dissolved solids concentrations.DiscussionInter-annual changes in zooplankton species composition showed that over time, large filters-feeders (e.g., large daphinids and calanoid copepods) were replaced by small cladocerans (e.g., bosminids) and generalist rotifers. The highest species richness was associated with the fluvial environment, whereas the highest abundance was associated with the transitional and lacustrine reservoir environments. Variations in water temperature, nutrients, and food availability explained the annual and seasonal changes in community structure, whereas variations in the water flow characteristics of the environments explained the longitudinal changes in the richness and abundance of zooplankton in reservoirs. The differences in zooplankton structure between the two reservoirs can be explained by the functional differences between the two systems, such as their WRTs and morphometrics.

Keibul Lamjao National Park (KLNP), Loktak lake Manipur, north-east India which is one of the 25 Ramsar sites of international importance and the biggest fresh water Lake in India. Macrophytes of the floating Phumdi mat environment of KLNP play an important role in the aquatic environment. An investigation was planned during the period of about three years from March, 2010 to December 2012, to study the diversity pattern of habitats of macrophytes available in six study sites of KLNP viz., 1.Kumbi, 2.Khordak, 3.Keibul, 4.Toya, 5. Nongmaikhong and 6. Sargam. All total 85 dominant plant species were recorded. Maximum plant species (49) was observed in Site-1 Kumbi (Altitude-780m) and minimum (27) in Site-3 Keibul (Altitude-772). The variation of plant species may be because of the slight variation of altitude. As the six study sites are distributed as floating aquatic environment in KLNP Loktak Lake, there is favourable place of the plants in higher altitude and altitude represents a complex gradient along which many environmental variables change concomitantly. In all the six study sites, common distribution of ten dominant plant macrophytes viz., Ageratum conizoides, Hedychium coronarium, Leersia hexandra, Oenanthe javanica, Phragmites karka, Polygonum sagittatum, Saccharum munja, Thelypteris interrupta and Zizania latifolia was noticed. Individual dominant plant was recorded in other sites also viz., Azola piñata in site-6; Xanthium atrumarium, Polygonum orientale, Dichrocephala latifolia and Cymbopogon citratus in site-2; Arundo plinii, Cuscuta reflexa, Gnaphalium luteo-album, Hydrilla verticillata, Marsilia minuta, Saccolepis interrupta, Selvenia cuculata and Utricularia spp. in site-1. Variation of IVI value of dominant plant species was observed in this study. Even though 85 dominant plants were selected for all the 6 sites, however, maximum plant richness expressed in IVI was recorded in case of Zizania latifolia (Site-5, IVI-87.5) and minimum IVI in case of Xanthium strumarium (Site-2, IVI-1.13). The diversity pattern and habitats of macrophytes in KLNP Phumdi environment might be due to water availability along the altitudinal gradient and other environmental factors suited in the study sites and expected to be an important factor affecting the survival and fecundity of plant population. We need to conserve the natural habitat of KLNP thereby maintaining the luxuriant growth of the seasonal and perennial, macrophytes, so as to maintain the natural flora and fauna of the park. These plants are the food of man and animal therefore, it needs a proper care and attention to protect them from over exploitation. Considering the diversity pattern of habitats of Macrophytes in KLNP, a floating mat Phumdi environment with high floral diversity and unique vegetation assemblage, it has been suggested that this track and adjoining sites should be declared as ecologically sensitive area not only the World Heritage Site.

Seasonal variations in the water quality of a tropical wetland dominated by floating meadows and its implication for conservation of Ramsar wetlands

Loktak Lake is the largest fresh water Lake in the North-eastern India. Keibul Lamjao National Park (KLNP) is a floating-mat (Phumdi) park inside the Lake. Study deals with the inter-related approaches: micobiological study, free-listing, participant observation and preference ranking of the six study sites of KLNP. Generally, plant collection per day was about 600 kg of Hedychium coronarium J. Koenig which were extracted from the park and found to be the most preferable species; while Persicaria sagittata (L.) H. Gross, as the least among the selected plants. Microbiological analysis of water for the six study sites recorded high pollution as evidenced by high values of Standard Plate Count (SPC) for bacteria ranging from 73,500-96,500 and microbial analysis of MPN (Most Probable Number) of coliform bacteria varies between100 and 320/100 ml and faecal coliform 95 and 200/100 ml. Free CO2 concentrations varied at the surface from 2-60 mg/l and 6-70 mg/l at the bottom of the park. In the KLNP environment the higher CO2 and lower concentrations of dissolved oxygen (DO) might be due to the floating mat (Phumdi) nature, in which light and exchange of gases does not occur as it does in the natural water bodies.

Aquatic insect diversity of a protected area, Keibul Lamjao National Park in Manipur, North East India

The zooplankton composition and distribution were studied during four oceanographic cruises in the Straits of Malacca between November 1998 and August 2000 with 140 μm-mesh and 45-cm diameter NORPAC net. Zooplankton samples were analyzed for the faunal composition and abundance. Zooplankton abundance peaked during pre-southwest monsoon (mean of 12, 918 ± 5, 635 ind. m3). Copepods were the most important constituents of the zooplankton in all areas. Copepods (including copepodites) accounted for 71.3%, 71.2%, 70.9% and 57.9% of the total zooplankton populations during consecutive cruises I, II, III and IV, respectively. Molluscs (6.3% to 12.4%) and crustacean's nauplii (4.4% to 6.0%) comprised the important groups of non-copepod zooplankton. Spatio-temporal variation in zooplankton abundance was not statistically significant. Zooplankton was more abundant in the near-coastal areas than in offshore areas, but the difference was not significant.

Objectives: A study on seasonal variation in zooplankton community was undertaken to evaluate the present status of water quality at Kadasgatti minor irrigation tank (MIT) located in the northern transitional zone of Belagavi district. Methods and Statistical Analysis: Water samples were collected from January 2017 to December 2017. Physico-chemical parameters and qualitative and quantitative analysis of zooplankton were carried out. Pearson correlation was calculated using SPSS, IBM Version 21 software to find out interrelationships between water quality and zooplankton groups. Findings: A total of 52 species of zooplanktons were recorded during the study period with a total zooplankton abundance of 14327 individuals with a relative abundance of 35.42%. Rotifera was the dominant group with 27 species, followed by Cladocera, Copepoda and Ostracoda. The highest zooplankton abundance was observed in summer while minimum in post-monsoon season. Copepoda was highest abundant group during the entire study period with its maximum abundance during winter and gradually declined and reached to its minimum in post-monsoon. The presence of eutrophic indicator species like Brachionus calyciflorus, Brachionus angularis, Filina longiseta suggests eutrophication of the tank. Novelty: The study provides baseline data on the present status of the water body indicating that, anthropogenic activities, agricultural runoff are the main cause of eutrophication. Sustainable and holistic conservational strategies have to be adopted to protect the water body. Keywords: Cladocera; Copepoda; Eutrophication; Rotifera; Seasonal variation; Zooplankton abundance

Samples were collected monthly from the sea area around Zhangzi Island, northern Yellow Sea, from July 2009 to June 2010. Vertical net towing was used to examine spatial and temporal variability in zooplankton abundance and biomass. Overall, Calanus sinicus and Saggita crassa were the dominant species found during the study period, while the amphipod Themisto gracilipes was dominant in winter and spring. Vast numbers of the ctenophore species of the genus Beroe were found in October and November. It was not possible to count them, but they constituted a large portion of the total zooplankton biomass. Zooplankton species diversity was highest in October, and species evenness was highest in April. Zooplankton abundance (non-jellyfish) and biomass were highest in June and lowest in August, with annual averages of 131.3 ind./m³ and 217.5 mg/m³, respectively. Water temperature may be responsible for the variations in zooplankton abundance and biomass. Beroe biomass was negatively correlated with other zooplankton abundance. Longterm investigations will be carried out to learn more about the influence of the environment on zooplankton assemblages.

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 influence of abiotic factors and chlorophyll a content in structuring the zooplankton assemblage. Among the environmental factors, zooplankton abundance correlated most strongly with turbidity. Turbidity was negatively correlated with species abundance, especially for Daphnia spp. and to the least extent for Diaphanosoma spp. Analysis of variance (ANOVA) was used to determine spatial (littoral, sublittoral and pelagic zone) and temporal (four seasons) variation in zooplankton abundance. We observed significant temporal differences in zooplankton abundance, with highest densities during dry season (November–April). Only cladocerans showed significant differences in habitat use (highest densities in the sublittoral zone). %

Zooplankton composition and abundance at two stations located in exposed (station I) and protected (station II) areas of Bakkhali sub-tropical estuary, Cox’s Bazar, Bangladesh were investigated monthly from January 2006 to December 2006. Thirty-three zooplankton taxa were identified. The major groups of zooplankton encountered were Copepoda, Chaetognatha, Mysidaceae, Luciferidae, Amphipoda, Acetes, Hydromedusae, Cladoceran, Decapod and fish larvae. The percent composition of Copepoda was the highest (79.5-84.8%) among zooplankton groups followed by Chaetognatha (5.5-6.0%) and Mysidaceae (3.3-6.8%). The abundance of zooplankton was relatively higher (87674individuals/m3) in protected (mangrove) as compared to exposed (salt marsh; 68719 individuals/m3) site during the study period. Canonical Correspondence Analysis indicated that the abundance of copepods was influenced by rainfall, water temperature and transparency in this estuarine environment, and considered coastal and estuarine dominant.Key words: Zooplankton, Mangrove, Salt marsh, Estuary and sub-tropical

Correction: Table 1 and Table 2 were omitted in from the PDF of this article. On 29th April 2015 the two tables were included in the PDF and the page numbers were changed from 151-158 to 151-160.Eight groups of zooplankton were found at Sitakunda coast, Chittagong, northeastern part of the Bay of Bengal during January to June 2007. The identified groups were Appendicularia (2.46%), Chaetognatha (2.45%), Cladocera (2.31%), Copepoda (26.05%), Ctenophora (5.86%), Crustacean zooplankton (21.64%), Ichthyoplankton (17.77%) and Meroplankton (21.45%). Abundance of zooplankton varied from 413 to 7730 individuals/m3.Mangrove vegetate area (station- VI) has the highest abundant possibly due to the organic and inorganic matters dissolved in the water while ship breaking area (station- IV) has the lowest abundant. Zooplankton population was significantly (p>0.05) higher in the mangrove vegetate area than the fishermen community area and ship breaking area. The mangrove vegetate area has the highest composition (57.06%) of zooplankton than the fishers community area and ship breaking area (29.77% and 13.16%, respectively). Calanus sp. (12.29%) belonging to Copepods and fish eggs (9.25%) belonging to Ichthyoplankton were the most abundant and Oikopleura albicans (0.66%) from Appendicularia, Metapenaeus brevicornis (0.71%) and Metapenaeus monoceros (0.90%) belonging to Crustacean larvae were the lowest abundant species found at three major investigated area.Res. Agric., Livest. Fish.2(1): 151-160, April 2015

The community structure of zooplankton has been conducted in the Lembeh Strait in Bitung and Wori Beach in Manado, North Sulawesi in October 2015. Sampling of this research was conducted in 22 sampling sites along the strait. Zooplankton samples were collected from 22 stations, by NORPAC 300 μm net that was vertically hauled from maximum 10 m depth up to the surface water. The samples were poured into the bottle with formalin of 4% as preservative. The results showed that there were 43 taxa of zooplankton. The abundance of zooplankton was between 21.216–4 193.776 ind./m3. The dominant taxa were copepod, especially Calanoida. The composition of zooplankton was relatively similar in all stations. We showed the abundance, dominance, composition and distribution of zooplankton at this research. More extensive studies concerning zooplankton is required to understand zooplankton biodiversity as a whole especially on the geographical and spatial distribution to describe population and community dynamic in the Lembeh Strait and Wori Beach.

Mountainous topography and solar elevation angle have a significant influence on the wind circulation and energy exchange over a complex region. Here, the seasonal variation of mountain-valley wind circulation (MVWC) and surface layer parameters have been presented over a hilly station of northeastern India. For the study, quick-response sonic anemometer data have been utilized. The solar elevation angle varies from 85° to 43° in different seasons and controls the MVWC over the terrain. MVWC was dominated in winter (WN), pre-monsoon (PM), and post-monsoon (PMN) seasons, while the synoptic wind predominates the wind direction over the terrain in monsoon (MN). In WN and PM, nighttime heat transmission from the atmosphere to the ground was −10 to −20 W m−2, while the minimum in MN and PMN was −3 to −7 W m−2. The net seasonal daily mean sensible heat flux (H) values from the surface to the atmosphere were 42 W m−2, 58 W m−2, 35 W m−2, and 34 W m−2 in WN, PM, MN, and PMN. In MN, the average daytime temperature was 8 °C, 0.5 °C, and 3 °C higher and at night was 9.5 °C, 2 °C, and 4.5 °C higher than the WN, PM, and PMN. In WN, PM, and PMN, the momentum flux had a higher value of about 2 to 3 h after the maximum value in H was attained at the 6-m and 10-m levels. The daytime turbulence kinetic energy was higher by 99%, 56%, 72%, and 93% than the nighttime during WN, PM, MN, and PMN.

<div><p><em>Flowering calendar of a particular area will give the information of the period and duration of flowering among plants. The purpose of the study is to investigate the presence of the habitat of some dominant macrophytes in Keibul Lamjao National Park (a Ramsar site) which have ethnobotanical relationships with human beings (the lake dwellers in particular and tourist in general) and wild animals. Flowering calendar of six study sites viz., Keibul, Nongmaikhong, Kumbi, Khordak, Sargam and Toyaching were studied and monthly flowering calendars were taken for two year period (2010 to 2011). Flowering calendars of the macrophytes were surveyed by following standard methodologies and comparison of the stages of flowering period of 6 study sites was incorporated. Maximum number of flowering plants (44) was recorded in Sargam, Khordak (32), Kumbi (30), Nongmaikhong (29) during the period September to November. Whereas, Toyaching reached 35, Keibul recorded lowest plant numbers (14) during the period June to August. Four plant species viz., Ageratum conyzoides, Alternanthera philoxeroides, Leersia hexandra and Hedychium coronarium were found throughout the year in all the 6 sites. From the findings, it can be concluded that flowering calendar will give the information of plants which are used as fodder for the wild animals like Sangai (Rucervus eldii eldii McClelland), an endangered deer species in this globe and ethnobotanically important plants of the lake dwellers as food, medicinal plants and allergens, thereby maintaining health status of man and animals. Conservation is required by controlling the human anthropogenic harassments, thereby maintaining the luxuriant growth of the seasonal and perennial, macrophytes observed during the study of flowering calendar, so as to maintain and conserve the natural flora and fauna of the park.</em></p></div>

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.