Copepod Diversity Research Articles

Water quality affects the structure of copepod assemblages along the Sfax southern coast (Tunisia, southern Mediterranean Sea)

The Sfax southern coast (Gulf of Gabes, Mediterranean Sea) has been under increased anthropogenic pressure for many years. In the present study we investigated the effects of this anthropisation on the spatial distribution of copepod assemblages in relation to the physicochemical features of seawater at 20 stations sampled on 19 March 2013. Copepods represented 73% of total zooplankton abundance. Small planktonic copepods (<1.45mm), including pollution-tolerant species (e.g. Oithona nana, Paracalanus parvus, Harpacticus littoralis and Tisbe battagliai), proliferated exclusively in stations of ~0.5-m depth characterised by high coastal anthropogenic inputs. The largest copepod species were dominated by Calanus helgolandicus (1.45–2.5mm) in the offshore zone in depths of ~3m. Substantial numbers of Oithona plumifera (7.5%) were found at depths between 0.5 and 3m. Copepod diversity was significantly higher in the southern zone, which is less affected by sewage, than in the northern zone, which was subjected to higher pressure (Shannon–Wiener index H′=1.5–2.5 and ≤1.5 bits individual–1). A shift in the planktonic copepod community between the two zones was linked to deterioration of water quality, with higher phosphorus levels, turbidity and chemical oxygen demand (COD) in the northern zone.

Ecological indicators and functional groups of copepod assemblages

Copepods are important ecological indicators of ecosystem functioning. In this study, we analyzed the structure of copepod assemblages and cross-shelf patterns based on functional traits and indicator value analysis. Copepod samples were collected from 54 stations distributed along the inner, middle, and outer continental shelves covering a wide geographical area (20,100km2). Overall, 38 species were identified: 20 Calanoida, 14 Cyclopoida, and 4 Harpacticoida. Copepod density was the highest in the inner shelf profile, with richness and diversity being higher on the outer shelf close to the shelf break. The results suggest that there is a gradient of zooplankton distribution even on narrow (<50km) continental shelves. The cluster analysis of the stations showed a tendency to form three groups largely corresponding to physical location. Two major functional groups were identified, sorted by spawning strategy. These were subdivided according to the trophic regime and feeding strategy. Temora turbinata (alien species), Clausocalanus furcatus, and Ditrichocorycaeus amazonicus (native species) were found to be ecological indicators. These species have different functional traits and distinct cross-shelf distributions, where the alien species dominates the turbid coastal waters, and C. furcatus is an indicator of outer-shelf waters. Thus, these species can be considered ecological indicators of the different continental shelf waters. The results indicate that it is necessary to understand the functional diversity and ecological indicators of copepods, considering their importance for the basis of marine food webs.

Keanekaragaman, Kelimpahan, dan Sebaran Kopepoda (Krustasea) di Perairan Bakau Segara Anakan, Cilacap

&lt;strong&gt;Diversity, Abundance, and Distribution of Copepods (Crustacea) in the Mangrove Area of Segara Anakan, Cilacap.&lt;/strong&gt; Observations on the diversity of Copepods, its abundance, and its distribution in three mangrove and estuarine locations in Segara Anakan Lagoon, Cilacap, were conducted in May (dry season) and November (rainy season) 2009. This study aims to determine the relationship of diversity and abundance of Copepods with some environmental factors that affect its distribution in the dry and rainy seasons. Copepod samples were taken from Kutawaru waters, Dermaga Sleko, and Ciperet using vertical and horizontal plankton nets, day and night. They were then preserved, deposited, and identified in MZB LIPI. There were 36 species of Copepods from 18 genera and 20 families, including 10 new records. The highest species diversity of Copepods was recorded in November, while the lowest was in May. The average abundance in May was higher than in November. The diversity and abundance in Ciperet in both dry and rainy seasons were always higher than the other two sites. Acartia erythraea, A. sinjiensis and Pseudodiaptomus annandalei were found to dominate the waters especially during the dry season in May. The community composition of Copepods occupying the waters was determined by salinity, while its activity and development were determined by temperature. &lt;br /&gt;

Response of Posidonia oceanica seagrass and its epibiont communities to ocean acidification.

The unprecedented rate of CO2 increase in our atmosphere and subsequent ocean acidification (OA) threatens coastal ecosystems. To forecast the functioning of coastal seagrass ecosystems in acidified oceans, more knowledge on the long-term adaptive capacities of seagrass species and their epibionts is needed. Therefore we studied morphological characteristics of Posidonia oceanica and the structure of its epibiont communities at a Mediterranean volcanic CO2 vent off Panarea Island (Italy) and performed a laboratory experiment to test the effect of OA on P. oceanica photosynthesis and its potential buffering capacity. At the study site east of Basiluzzo Islet, venting of CO2 gas was controlled by tides, resulting in an average pH difference of 0.1 between the vent and reference site. P. oceanica shoot and leaf density was unaffected by these levels of OA, although shorter leaves at the vent site suggest increased susceptibility to erosion, potentially by herbivores. The community of sessile epibionts differed in composition and was characterized by a higher species richness at the vent site, though net epiphytic calcium carbonate concentration was similar. These findings suggest a higher ecosystem complexity at the vent site, which may have facilitated the higher diversity of copepods in the otherwise unaffected motile epibiont community. In the laboratory experiment, P. oceanica photosynthesis increased with decreasing pHT (7.6, 6.6, 5.5), which induced an elevated pH at the leaf surfaces of up to 0.5 units compared to the ambient seawater pHT of 6.6. This suggests a temporary pH buffering in the diffusive boundary layer of leaves, which could be favorable for epibiont organisms. The results of this multispecies study contribute to understanding community-level responses and underlying processes in long-term acidified conditions. Increased replication and monitoring of physico-chemical parameters on an annual scale are, however, recommended to assure that the biological responses observed during a short period reflect long-term dynamics of these parameters.

Cladocera and Copepoda of Shokalsky Island: new data from northwest Siberia

ABSTRACTInformation on the freshwater fauna of the remote Arctic territories is very patchy, and most of the isolated islands of the Arctic Ocean remain absolutely unexplored. The pioneer data on the species composition of microcrustaceans of Shokalsky Island (northwest Siberia, Russia) is reported here. The initial three-year research revealed a total of 31 new for the area species of Cladocera and Copepoda, including new records for the whole of northwestern Siberia. Comparing the interannual differences in faunal composition, we suggested the hypothesis of the existence of a cryptic pool of species’ resting stages, which can invade the community in the event of favourable environmental conditions in the Arctic freshwaters. We also compiled all the available data from different parts of northern Siberia and compared them with the fauna of Shokalsky Island to analyse the connection between the diversity and distributional patterns of copepods and cladoceran species and the climate conditions of different territories.

Unravelling diversity of deep-sea copepods using integrated morphological and molecular techniques

Accurate species identification is crucial for ecological studies. For copepods, this is usually based on a few diagnostic morphological characters, which can be highly conserved, resulting in an underestimation of species diversity in many copepod families. We elucidate species richness in the morphologically challenging and ecologically important deep-sea copepod family Spinocalanidae in the tropical Atlantic by applying an integrated taxonomic approach combining morphology, DNA-sequence analyses and proteomic fingerprinting. In total, 28 morphospecies could be discriminated, while 39 putative species were detected using DNA-sequence analyses and 42 using proteomic fingerprinting. This outcome verifies proteomic fingerprinting to simplify and accelerate future biodiversity studies of copepods with high taxonomic resolution. Our findings demonstrate the power of this integrated morphological and molecular taxonomic approach by revealing high numbers of cryptic or pseudocryptic species and thus uncovering the incompleteness of taxonomic guides for this group in the poorly explored mesopelagic realm. Furthermore, our analyses reveal a close relationship of Mospicalanus and Spinocalanus group A and indicate that the genus Spinocalanus may be polyphyletic. The underestimated species diversity suggests complex ecological interactions in terms of predator–prey relationships, interspecific competition and species-specific specializations in the vast, but under-studied mesopelagic realm.

Seasonal variations in abundance and diversity of copepods in Mond River estuary, Bushehr, Persian Gulf

Abstract. Hedayati A, Pouladi M, Vazirizadeh A, QadermarziA, Mehdipour N. 2017. Seasonal variations in abundance and diversity of copepods in Mond River estuary, Bushehr, Persian Gulf. Biodiversitas 18: 447-452. The present study was carried out to investigate the abundance and biodiversity of copepods from Mond River (MR) estuary, Bushehr, Persian Gulf during 4 seasons and their relationships with environmental factors. The water samples were collected in mid-season from spring 2012 to winter 2013 for one year period. Copepod samples were collected by using of 140 µm plankton net with 25 cm mouth diameter and vertical towing in all stations. Copepod assemblages were comprised of 4 orders, 13 families and 10 genera. Orders were included; Calanoida, Cyclopoida, Poecilostomatoida, Harpacticoida and Genera were included: Cathocalanus, Acrocalanus, Paracalanus, Subeucalanus, Centropages, Temora, Calanopia, Labidocera, Pontella, Acartia, Oithona, Oncaea, Corycaeus, Microsetella, Microsetella and Euterpina. The order Calanoida with 10 genera was the most diverse and dominant order between Identified orders. The means (±SE) of copepods abundance were recorded in spring (5853.4±1826.19 Individual m-3), in summer (6707.6±1930.15 Ind. m-3), in fall (4393.6±1263.37 Ind. m-3) and in winter (3400±763.98 Ind. m-3), respectively. Simpson and Shannon-Wiener biodiversity indices were obtained in spring (0.87±0.11 and 2.86±0.19), in summer (0.89±0.006 and 3.11±0.15), in fall (0.86±0.13 and 2.66±0.2) and in winter (0.83±0.12 and 2.39±0.15), respectively. The copepod assemblages had most amounts of diversity and abundance at station 5 in all seasons. Pearson correlation showed significant correlation between copepod diversity and abundance with salinity, pH and temperature. Results showed that salinity factor was more effective environmental factor on Simpson (0.01&gt; P and r=0.783) and Shannon-Weiner indices (0.01&gt; P and r=0.727), and copepods abundance (0.01&gt; P and r=0.664) in MR estuary.&#x0D; Keywords: Abundance, copepod, diversity, environmental factor, Mond Estuary

Abundance, distribution, diversity and zoogeography of epipelagic copepods off the Egyptian Coast (Mediterranean Sea)

The abundance, distribution and diversity of epipelagic copepods were studied along the Egyptian Mediterranean Coast during April, August, 2008, February, 2009 and 2010. The geographical distribution and ecological affinities of the recorded species are presented in order to follow up the migrant species that recently entered in the study area. Copepoda was the most dominant zooplankton group, representing 74.14% of the total zooplankton counts. The annual averages of copepod abundance in the coastal, shelf and offshore zones were 699.3, 609.7 and 555.7ind.m−3, respectively. Spring was the most productive and diversified season. 118 copepod species were identified in the study area; among them twelve species are recorded in the Mediterranean Sea for the first time and 41 species are new records in the Egyptian Mediterranean waters. The community was dominated by Oithona nana, Calocalanus pavo, Nannocalanus minor, Clausocalanus arcuicornis and Paracalanus parvus. The study area could be considered as a crossroad for migration process from Atlantic Ocean in the west and Indian Ocean via Red Sea and Suez Canal from the south. In addition, the maritime activities in the Mediterranean Sea may have contributed into the change of copepod diversity in the study area where some species could have come to the Egyptian Coast from other water systems via ballast water.

Expanding zooplankton standing stock estimation from meso- to metazooplankton: A case study in the N. Aegean Sea (Mediterranean Sea)

Although metazooplankton includes a wide size range of organisms, our knowledge is essentially based on mesozooplankton. A first estimation of the metazooplankton standing stock in a Mediterranean area, and of its size fractions and functional groups are provided by combining data out of three nets with different mesh sizes (45, 200 and 500µm). Data were collected along a gradient of oligotrophy in the frontal area created, where the waters of Black Sea origin meet those of Levantine Sea origin (Northeast Aegean Sea, Eastern Mediterranean). Metazooplankton biomass was dominated by mesozooplankton (0.2–2mm), while meso- and microzooplankton (<0.2mm) shared dominance of abundance. Copepods dominated both in abundance and biomass and were followed by nauplii in abundance and gelatinous carnivores or decapod-euphausiid larvae in biomass. The spatiotemporal variability of metazoans stock, biomass-size spectra linearity, carnivorous group contribution and copepod diversity, supported that metazooplankton tends to recede from steady-state when approaching less oligotrophic dynamic areas (such as fronts) or dynamic periods (such as the spring bloom). The need and the difficulties of obtaining a larger picture from a wider size range of metazoans for understanding the role of zooplankton are stressed.

Copepods associated with scleractinian corals: a worldwide checklist and a case study of their impact on the reef-building coral Pocillopora damicornis (Linnaeus, 1758) (Pocilloporidae).

The Cnidaria have more symbiotic copepods than any other group of invertebrates, and the greatest numbers of these associates occur on hard corals. A review of the scattered literature on the diversity and taxonomic composition of scleractinian-associated copepods and their hosts revealed a total of 148 coral species, representing 66 genera and 15 families that serve as hosts to copepods. At present, 363 copepod species, representing 99 genera, 19 families and three orders, have been recorded as associates of scleractinian corals. The total included 288 cyclopoids, 68 siphonostomatoids and seven harpacticoids. Within the Cyclopoida the representation of species varied greatly among the 13 families, with a disproportionate number of species belonging to the Anchimolgidae (141 species) and Xarifiidae (92 species). Data on host utilization and geographical distribution of all copepods living symbiotically with hard corals is synthesized and host specificity patterns are highlighted.The prevalence, intensity, density, and biodiversity of copepod infection of 480 colonies of the reef-building coral Pocillopora damicornis (Linnaeus, 1758) from Nanwan Bay, southern Taiwan were documented between July 2007 and November 2008. It was hypothesized that certain environmental factors and physiological coral traits, such as the density of Symbiodinium, could influence these infection parameters. Analysis revealed that ectoparasitic copepods were the most likely to infect P. damicornis, and that Asteropontius minutus Kim, 2003 accounted for more than 50% of total copepod density in July-September 2007 when temperatures were high and bleaching occurred in ~75% of the sampled colonies. The data further showed that copepod virulence may be related to their life history strategies, as well as to Symbiodinium density, surface area of the host coral colonies, and concentration of nitrate and chlorophyll-a in the surrounding seawater. By tracking the abundance, diversity, and performance of infectious copepods prior, throughout, and after a natural bleaching event, the potential to use these parasites as bioindicators for predicting the future physiological performance of P. damicornis in response to environmental change, particularly bleaching events, may ultimately be further explored, developed and maximized.Humesimyzon Kim, 2010, previously placed in the Asterocheridae, is tentatively transferred to the recently resurrected family Coralliomyzontidae. The authorship and spelling of Pseudanthessius thorellii (Brady, 1880) are corrected.

Microcystins affect zooplankton biodiversity in oxbow lakes.

The authors tested the hypothesis that zooplankton diversity and density are affected by the presence of cyanotoxins in the water. The authors focused on 4 oxbow lakes of the Vistula River in southern Poland, which are subjected to mass cyanobacterial development. In 2 of the oxbows (Piekary and Tyniec), microcystins released into the water were found. The highest concentration of microcystins (0.246 μg/L) was observed for microcystins LR. Zooplankton diversity showed a weak response to the presence of microcystins released into the water. The Shannon index (H') of total zooplankton diversity decreased in the Piekary and Tyniec oxbows during periods when the microcystin concentrations were highest. The same trend was noted for diversity of rotifers in both oxbows and for diversity of copepods in Piekary, but not for copepods in Tyniec. No such trends were found for the diversity of cladocerans in any of the oxbows, nor was a relationship found between density of zooplankton and microcystins. Statistical analyses showed that the number of species in individual samples was negatively correlated with the levels of sulfates, phosphates, and ammonia, but the microcystin concentration was positively related to those levels. This points to the complexity of the interactions and synergies among toxins, abiotic factors, and zooplankton biodiversity. In focusing on the problem of cyanotoxins, conservation studies should pay attention to this complexity. Environ Toxicol Chem 2017;36:165-174. © 2016 SETAC.

Copepod colonization of organic and inorganic substrata at a deep-sea hydrothermal vent site on the Mid-Atlantic Ridge

The few existing studies on deep-sea hydrothermal vent copepods indicate low connectivity with surrounding environments and reveal high endemism among vents. However, the finding of non-endemic copepod species in association with engineer species at different reduced ecosystems poses questions about the dispersal of copepods and the colonization of hydrothermal vents as well as their ecological connectivity.The objective of this study is to understand copepod colonization patterns at a hydrothermal vent site in response to environmental factors such as temperature and fluid flow as well as the presence of different types of substrata. To address this objective, an in situ experiment was deployed using both organic (woods, pig bones) and inorganic (slates) substrata along a gradient of hydrothermal activity at the Lucky Strike vent field (Eiffel Tower, Mid-Atlantic Ridge). The substrata were deployed in 2011 during the MoMARSAT cruise and were recovered after two years in 2013.Overall, copepod density showed significant differences between substrata types, but was similar among different hydrothermal activity regimes. Highest densities were observed on woods at sites with moderate or low fluid input, whereas bones were the most densely colonized substrata at the 2 sites with higher hydrothermal influence. Although differences in copepod diversity were not significant, the observed trends revealed overall increasing diversity with decreasing temperature and fluid input. Slates showed highest diversity compared to the organic substrata. Temperature and fluid input had a significant influence on copepod community composition, resulting in higher similarity among stations with relatively high and low fluid inputs, respectively. While vent-specialists such as dirivultids and the tegastid Smacigastes micheli dominated substrata at high vent activity, the experiment demonstrated increasing abundance and dominance of non-vent taxa with decreasing temperature and fluid input. Effects of the substratum type on community composition were not significant, although at sites with moderate or low fluid input, woods exhibited distinctive communities with high densities and relative abundance of the taxon Nitocrella sp. In conclusion, copepod colonization and species composition were mainly influenced by hydrothermal fluid input and temperature rather than the type of substratum. The outcome of this study provides fundamental knowledge to better understand copepod colonization at hydrothermal vents.

Temporal changes in pelagic copepod assemblages off Ubatuba, Brazil

AbstractThe inner shelf waters off Southeastern Brazil are periodically enriched by bottom intrusions of the cold and nutrient‐rich South Atlantic Central Water (SACW), which is transported offshore by the Brazil Current. This study examined the temporal contrasts in abundance and structure of pelagic copepod assemblages in a neritic station off Ubatuba, in relation to hydrography and phytoplankton biomass, to investigate the effects of SACW bottom intrusions on copepod population dynamics during three consecutive years. The water‐column characteristics shifted from a well‐mixed, more turbid and phytoplankton‐poor scenario during subsidence conditions to a stratified, less turbid and high Chl‐a concentration scenario during SACW bottom intrusions, leading to increased copepod diversity, abundance, and biomass. The rise in copepod diversity during SACW intrusions was related to the contribution of oceanic species in addition to coastal water species. The copepod community was numerically dominated by small‐sized species, such as Oncaea waldemari, Oithona plumifera, and clausocalanid and paracalanid copepodids, regardless of seasonality and SACW intrusions. Some large calanoid species contributed considerably to the total copepod biomass during intrusions. In addition to confirming that SACW seasonal intrusions play a key role in pelagic processes off Southeast Brazil, this study showed that the multiannual variability of SACW seasonal intrusions is important in regulating the structure and dynamics of copepod communities in this subtropical area.

Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle

The aim of this study is to analyze the annual zooplankton succession at a coastal station in Patagonia (Argentina), with special emphasis on copepods and their potential preys, using solar radiation and temperature as environmental factors. The annual plankton cycle exhibited autumn/winter and spring/summer phases. During the autumn/winter phase, low temperature and radiation were correlated with higher diatom abundance and copepod diversity. This period was characterized by a dominant classical herbivorous food web in which the large copepod Calanoides carinatus dominated the community. On the contrary, during the spring/summer period, with high radiation and temperature levels, flagellates were the dominant food available for zooplankton and correlated with smaller species of copepods such as the harpacticoid Euterpina acutifrons. Also, intensive reproduction of the small copepods E. acutifrons and Paracalanus parvus occurred mainly in summer. On the other hand, high species diversity was found in winter when the ultraviolet radiation was low. The temporal pattern of the copepods observed in our study was explained by food availability and environmental factors (temperature and solar radiation), although other factors such as predator abundance may also be important in modulating the community. Our results show the importance of copepod abundance dynamics and highlights their key role in the pelagic food web in northern Patagonian coastal waters.

Influence of Kuroshio water on the annual copepod community structure in an estuary in the northwest Pacific Ocean

The influence of Kuroshio water on temporal distribution and copepod diversity was investigated in the Lanyang River estuary (LRE), the longest river in northeast Taiwan, to assess secondary productivity. Zooplankton samples were collected bimonthly from the surface waters (0–2m) of the estuary during cruises in 2006. Hydrological parameters indicated that the water in the LRE was an admixture of the Lanyang River water and seawater. Among the different genera, 47 copepod species (including 10 species that were identified only to the generic level) belonging to 28 genera, 16 families, and 4 orders were identified. The abundance and proportion of copepods to the total zooplankton counts range from 0 to 3683.42 (304.9±692.7 individuals m−3) and from 0 to 100 (55.09±34.84%) respectively. The copepod community structure revealed a distinct seasonal succession and showed significant differences among the sampling cruises (p<0.05, One-way ANOVA). The 5 most abundant species were Parvocalanus crassirostris (relative abundance [RA]: 50.93%), Pseudodiaptomus serricaudatus (RA: 16.85%), Euterpina acutifrons (RA: 7.34%), Cyclops vicinus (RA: 4.82%), and Microcyclops tricolor (RA: 3.15%). The abundance, species number, indices of richness, evenness, and copepod diversity varied significantly (p<0.05, One-way ANOVA) for all the cruises. Pearson correlation analysis results demonstrated that salinity was positively correlated with the copepod species number (r=0.637), total copepod abundance (r=0.456), and Shannon–Wiener diversity index (r=0.375) with a 1% level of significance. By contrast, the evenness index was negatively correlated with salinity (r=−0.375, p=0.01), indicating that copepod diversity in the LRE was influenced mainly by seawater. The Kuroshio Current played a major role in transporting and distributing warm-water copepods to its affected area. Copepod species assemblages showed seasonal succession and varied drastically with tidal change. The latter registered high abundance, and the presence of the highest number of species was correlated with intruding seawater.

First insights into genus level diversity and biogeography of deep sea benthopelagic calanoid copepods in the South Atlantic and Southern Ocean

Calanoid copepods constitute the most numerous organisms not only in the pelagic realm, but also in the benthic boundary layer, which gives them an important role in the turnover of organic matter in the benthopelagic habitat. During seven expeditions to the South Atlantic and Southern Ocean, the diversity and biogeography of deep-sea benthopelagic calanoid copepods were studied. The communities of calanoids living in the vicinity of the seabed were characterized by high diversity comparable to many pelagic habitats, but low abundance of individuals. Members of the taxon Clausocalanoidea dominated the communities, and within this taxon most individuals belonged to detritivore calanoids characterized by sensory setae on the second maxillae or aetideid copepods. 73% of all genera classified as obligate or predominantly benthopelagic copepods detected during these expeditions were new to science and a vast number of genera and species have been described since then. Comparing the communities of calanoid genera between different regions, the assemblages in the Southern Ocean differed significantly from the Southeast and Southwest Atlantic. A latitudinal diversity gradient could be observed, with highest numbers of genera in the Southwest Atlantic and low numbers at stations in the Southern Ocean. Reviewing the literature, endemism for benthopelagic calanoids appeared to be low on a latitudinal range caused by connectivity in benthopelagic habitats through spreading water masses. However, considering the habitats structuring the water column vertically, a high number of genera are endemic in the benthopelagial and specialized to living within the vicinity of the seabed.

Assessing the diversity of New Zealand freshwater harpacticoid copepods (Crustacea: Copepoda) using mitochondrial DNA (COI) barcodes

Taxonomic and ecological studies of freshwater harpacticoid copepods are limited globally by the ability to easily and accurately identify specimens. Here, we test the use of the mitochondrial cytochrome c oxidase subunit I (COI) gene locus as a tool for assessing the diversity of freshwater Harpacticoida. We obtained sequences from New Zealand harpacticoid copepods, representing two families, five genera and nine species, including the non-indigenous Elaphoidella sewelli. All species were delineated by the COI gene. However, high intraspecific diversity was evident among populations of Elaphoidella bidens (>12%), and between North and South Island populations of Bryocamptus pygmaeus (>18%), potentially indicating the presence of morphologically cryptic taxa. We suggest that mitochondrial DNA (COI) sequences can provide a useful tool for the routine identification of freshwater harpacticoid copepods. Applications of these data will include assessing species diversity and biogeography as well as assisting with the detection of non-indigenous species.

Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

In order to characterize the copepod communities associated with tubeworm and mussel aggregations around a hydrocarbon seep in the Green Canyon of the Gulf of Mexico, diversity, abundance, and community composition were analyzed. Also analyzed were species biogeography and the potential connectivity to other chemosynthesis-based habitats. Copepod abundance and biomass were very low among tubeworms and mussels, with 0.22 to 6.08 individuals per 10 cm2 sampled area and 9.02 to 42.43 μg wet weight 10 cm2 sampled area, respectively; but, abundance was significantly higher among the mussels. Fifty-five copepod species were identified, of which most were newly discovered and primarily belonging to the Harpacticoida order. Four copepod species were previously recorded from other food-rich and hard-substrata environments, such as hydrothermal vents or wood falls. Another four species showed close morphological proximity to species described from cold seeps, hydrothermal vents, and wood falls. Copepod diversity and community composition showed no significant differences between the foundation species. However, differences in the relative abundance and dominance of single species indicate a rather homogeneous community in mussel beds and a more heterogeneous community among tubeworms, indicating that foundation species may shape the abundance and community composition of associated copepods at cold seeps.

Zooplankton Diversity, Species Richness and their Distribution Pattern in Bhimtal Lake of Kumaun Region, (Uttarakhand)

Bhimtal Lake situated in Uttarakhand, India, and has been devastated due to anthropogenic activities. In this study we examined the diversity and distribution pattern of zooplanktons in the Bhimtal Lake, along with evaluation of the relationships among different zooplankton groups and abiotic factors during the period September, 2013 to August, 2014. Sampling was done seasonally, during summer, winter and monsoon seasons, at three sites in Bhimtal lake. Sample analysis revealed the presence of 29 species of zooplankton including 16 species of Rotifers, 8 species of Cladocera and 5 species of Copepods. Rotifera group was the most dominant among all three groups. Positive co-relation was found between zooplankton growth with water temperature and pH while, there growth was adversely affected with increasing alkalinity, nitrates and dissolved oxygen. The diversity of Rotifers, Cladocera and Copepods were highest during summer, and was lowest during winter, while their density and biomass were found to be highest at the surface water during summer. It can be stated that the tropic nature of Bhimtal Lake may have been changed to mesotrophic conditions.

Effect of atmospheric precipitation and the abundance of semiaquatic bird colonies on zooplankton in the littoral of a small high-trophic lake

It is shown that, when the amount of atmospheric precipitation increases, the changes in zooplankton indices in the background area in the littoral zone of a high-trophic lake are similar to those observed under increased organic and biogenic load in the course of anthropogenic eutrophication: the diversity and abundance of rotifer increase and the indices of development of rotifers decrease. In the area subjected to the effect of products of bird vital activity, the increase in the abundance of their colony and the surface runoff lead to a reduction in the number of species (due to diversity of rotifers and copepods), the abundance and biomass of zooplankton, the portion of Rotifera and Cladocera in the total abundance and biomass of the community, and the Shannon index; however, the indexes of Copepoda development increase. The decrease in the amount of atmospheric precipitation at both sites of the littoral zone leads to a decrease in the abundance of Copepoda and an increase in the abundance of Rotifera and Cladocera. But at the site of a heron breeding colony, zooplankton is characterized by the highest development of copepods and the lowest development of rotifers and cladocerans.