Copepod Species Richness Research Articles

Trophic Positions of Sympatric Copepods across the Subpolar Front of the East Sea during Spring: A Stable Isotope Approach

We investigated the trophic relationship between particulate organic matter (POM) and sympatric copepods within the epipelagic zone (~200 m depth) in the East Sea during spring based on stable isotope analysis (SIA). The SIA indicated that interspecific differences in the prey size and vertical segregation of feeding migration range among copepods may promote niche partitioning among sympatric copepods in each region of the subpolar front (SPF). Additionally, our results showed remarkable differences in the copepod community structure and resource utilization across the SPF. The south region of the East Sea showed higher species richness of copepods than the north region, while copepods that fed mainly on POM in the surface and subsurface chlorophyll maximum layers showed smaller body sizes in the south region. These results revealed that the food chain between primary producers and higher trophic levels was longer in the south region than in the north region. Additionally, δ13C and δ15N values of copepods increased gradually with the body size increase whereas δ15N values in the north region showed the reverse trend. Latter results could be attributed to the consumption of deep-layer POM in small copepods. Therefore, we suggest that northward shifts in the distribution of copepods under global warming may decrease energy efficiency in the pelagic ecosystem of the East Sea.

Puget Sound Chum Salmon Growth Linked to Competitor Abundance, Climate Indices, and Copepod Species Richness

AbstractAn improved understanding of the mechanisms influencing productivity of fish populations is critical for accurately determining harvest rates and identifying years of conservation concern. Here we reconstruct yearly scale growth of three Puget Sound (PS) Chum Salmon Oncorhynchus keta stocks over 16 brood years (1997–2012) to better understand how variation in marine growth may be related to environmental factors, intra‐ and interspecific competition, and stock productivity. Generalized additive mixed models identified copepod species richness in the northern California Current and the abundance of PS Pink Salmon O. gorbuscha and Chum Salmon as strong predictors of first‐year growth, the latter indicative of density‐dependent effects as the abundance of local competitors (Pink and Chum salmon) increased. Second‐year growth was negatively related to the Aleutian Low–Beaufort Sea Anticyclone (ALBSA), a recently defined metric of the Aleutian Low, and showed a nonlinear positive to negative relationship with sea surface temperature in the Gulf of Alaska. Puget Sound Chum and Pink Salmon abundances were also significantly related to second‐year growth but did not suggest density‐dependent effects like those observed in ocean year 1. Third‐year growth was closely related to large‐scale climate indicators, demonstrating a nonlinear negative to positive relationship with the North Pacific Gyre Oscillation, a negative relationship with ALBSA, and a negative relationship with North Pacific Pink Salmon abundance when catch statistics indicated that abundance was high. Models indicated that PS Chum Salmon stock productivity (recruits per spawner) was positively correlated with back‐calculated first‐year growth and negatively correlated with second‐ and third‐year growth, suggesting that for brood years whose surviving adults experienced rapid early marine growth, there were cohort survival benefits. As new relationships between large‐scale indicators and Pacific salmon stocks are identified, incorporating these indicators into forecasting efforts is paramount for effective and sustainable management of fishery resources.

Biogeographic patterns of planktonic and meiobenthic fauna diversity in inland waters of the Russian Arctic

Abstract Broad‐scale assessment of biodiversity is needed for detection of future changes across substantial regions of the Arctic. Presently, there are large data and information gaps in species composition and richness of the freshwater planktonic and meiobenthos communities of the Russian Arctic. Analysis of these data is very important for identifying the spatial distribution and temporal changes in species richness and diversity of rotifers, cladocerans, and copepods in the continental Russian Arctic. We investigated biogeographic patterns of freshwater plankton and meiobenthos from c. 67° to 73°N by analysing data over the period 1960–2017. These data include information on the composition of rotifers, cladocerans, and copepods obtained from planktonic and meiobenthic samples, as well as from subfossil remains in bottom sediments of seven regions from the Kola Peninsula in the west, to the Indigirka River Basin (east Siberia) in the east. Total richness included 175 species comprised of 49 rotifer genera, 81 species from 40 cladoceran genera, and 101 species from 42 genera of calanoid, cyclopoid, and harpacticoid copepods. Longitudinal trends in rotifer and micro‐crustacean diversity were revealed by change in species composition from Europe to eastern Siberia. The most common and widespread species were 19 ubiquitous taxa that included Kellicottia longispina (Rotifera), Chydorus sphaericus s. lat. (Cladocera), Heterocope borealis, Acanthocyclops vernalis, and Moraria duthiei (Copepoda). The highest number of rare species was recorded in the well‐studied region of the Bolshezemelskaya tundra and in the Putorana Plateau. The total number of copepod and rotifer species in both Arctic lakes and ponds tended to increase with latitude. Relative species richness of copepods was positively associated with waterbody area, elevation, and precipitation, while relative species richness of cladocerans was positively related to temperature. This result is consistent with known thermophilic characteristics of cladocerans and the cold tolerance properties of copepods, with the former being dominant in shallow, warmer waterbodies of some western regions, and the latter being dominant in large cold lakes and waterbodies of eastern regions. Rotifers showed a negative association with these factors. Alpha‐ and β‐diversity of zooplankton in the Russian Arctic were strongly related to waterbody type. Lake zooplankton communities were more diverse than those in pond and pool systems. Moreover, the highest β‐diversity values were observed in regions that showed a greater breadth in latitude and highly heterogeneous environmental conditions and waterbody types (Bolshezemelskaya tundra and Putorana Plateau). Redistribution of freshwater micro‐fauna caused by human activities occurred in the 1990s and 2000s. As a result of climate warming, a few cladoceran species appear to have extended their range northward. Nevertheless, the rotifer and micro‐crustacean fauna composition and diversity of the majority of Arctic regions generally remain temporally conservative, and spatial differences in composition and species richness are chiefly associated with the differences between the warmer European and colder east Siberian climates.

Copepod community structure during upwelling and non-upwelling seasons in coastal waters off Cochin, southwest coast of India

Vypeen, an island of Cochin estuarine system, acts as the spawning site of several marine and estuarine fishes. We assumed that, physical process (upwelling) make changes in hydrography and the production of chlorophyll a in coastal waters off Vypeen. These alterations can influence the zooplankton abundance and copepod community structure in that area. For justifying this hypothesis, samples were collected from Vypeen at 10 m and 30 m locations during January (pre-southwest monsoon), August (late-southwest monsoon) and November (post-southwest monsoon) 2014. During August, subsurface water column was cool, nutrient rich and less oxygenated (signatures of upwelling) than in November and January. Maximum concentrations of nitrate and chlorophyll a were recorded during August. In the present study, 15 zooplankton groups were recorded; of which copepods were the most predominant group (73%–90%). Copepod density in the present study ranged between 527.2 ind./m2 and 5 139.2 ind./m2. Totally, 37 copepods species were reported in present study and copepod species richness was higher during January. The abundance of zooplankton and copepods was high in August during late-southwest monsoon. These variations were closely associated with the coastal upwelling in August and weakening of moderate upwelling in November. In SIMPER analysis, it was found that the copepods species distribution was similar within season and dissimilar between the three seasons. Moreover, the higher abundance of upwelling indicator species Temora turbinata was recorded in August, which confirms the signs of seasonal upwelling in Vypeen. The present study emphasized on the influence of hydrographical parameters associated with physical process, in governing the copepod community organization of the Vypeen Island.

Trapped in the web of water: Groundwater-fed springs are island-like ecosystems for the meiofauna.

We investigated whether the equilibrium theory of island biogeography (ETIB) can be applied to the meiofauna of groundwater‐fed springs. We tested whether copepod species richness was related with spring area, discharge, and elevation. Additionally, five hypotheses are tested based on species distribution patterns, dispersal ability, and life‐history characteristics of several guilds (stygobiotic, nonstygobiotic, cold stenotherm, and noncold stenotherm species). Thirty springs in the central Apennines (Italy) were considered. A multimodel selection procedure was applied to select best‐fit models using both ordinary least‐squares regressions and autoregressive models. Mantel tests were used to investigate the impact of spatial autocorrelation in determining interspring similarity (ßsor), pure turnover (ßsim), intersite nestedness (ßnest = ßsor − ßsim), and matrix nestedness (measured using NODF and other metrics). Explicit consideration of spatial correlations reduced the importance of predictors of overall species richness, noncold stenotherm species (both negatively affected by elevation), cold stenotherm species, and nonstygobiotic species, but increased the importance of area for the stygobiotic species. We detected nested patterns in all cases, except for the stygobites. Interspring distances were positively correlated with ßsor and ßnest (but not with ßsim) for the entire data set and for nonstygobiotic, cold stenotherm, and noncold stenotherm species. In the case of stygobites, interspring geographical distances were marginally correlated with ßsor and no correlation was found for ßsim and ßnest. We found support for ETIB predictions about species richness, which was positively influenced by area and negatively by elevation (which expresses the size of source of immigrants). Low turnover and high nestedness are consistent with an equilibrium scenario mainly regulated by immigration and extinction. Stygobites, which include many distributional and evolutionary relicts, have a low capability to disperse through the aquifers and tend to be mainly confined to the springs where they drifted out and were trapped by springbed sediments.

Response of marine copepods to a changing tropical environment: winners, losers and implications

Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified.Methods. Zooplankton samples were collected during two time periods (1985–86 and 2014–15) interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI) design. Copepods were identified to species, and results were interpreted by univariate (ANOVA) and multivariate (PERMANOVA, PCO) analyses of the computed species abundance and diversity measures.Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus) were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica). Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons) were unaffected. Centropages tenuiremis was likely an introduced species. There was no significant loss in species richness of copepods despite the dramatic changes in community structure.Discussion. Sea warming and other human-induced effects such as eutrophication, acidification and coastal habitat degradation are likely the main factors that have altered copepod community structure. The large-bodied estuarine and coastal calanoid copepods are surmised to be vulnerable to eutrophication and hypoxia, while both resilient and opportunistic species are largely unaffected by, or adaptable to, degraded coastal environments and observed sea surface temperature (SST) rise. It is forecasted that SST rise with unmitigated anthropogenic impacts will further reduce large-bodied copepod species the favoured food for fish larvae with dire consequences for coastal fish production.

西泉眼水库夏季浮游动物群落结构特征及水质评价

PDF HTML阅读 XML下载 导出引用 引用提醒 西泉眼水库夏季浮游动物群落结构特征及水质评价 DOI: 10.5846/stxb201501280226 作者: 作者单位: 东北林业大学,东北林业大学,黑龙江省水利厅,黑龙江省水利厅,东北林业大学,东北林业大学,东北林业大学,东北林业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（40830535）；黑龙江省科技攻关项目（GB09C103） The zooplankton community structure and water quality of Xiquanyan Reservoir Author: Affiliation: Northeast Forestry University,Northeast Forestry University,Department of water resources of Heilongjiang Province,Department of water resources of Heilongjiang Province,Northeast Forestry University,Northeast Forestry University,Northeast Forestry University,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2010年夏季，对西泉眼水库浮游动物及水质理化指标进行了调查，分析了该水库浮游动物群落结构特征，运用现存量法、指示生物法、多样性分析法、QB/T指数法、E/O指数法、肥度指数法（E'）和理化因子分析法评价了水质等级，应用典范对应法分析了浮游动物与环境因子之间的相关性。结果表明：浮游动物56种，优势种为褐砂壳虫Difflugia avellana、长三肢轮虫Filinia longiseta、针簇多肢轮虫Polyarthra trigla、微刺小剑水蚤Microcyclops inchoatus和无节幼体；污染指示种53种，丰度为46.13 个/L，生物量为0.137mg/L；Shannon-Wiener指数为2.78，Margalef丰富度指数为1.97，QB/T指数为2.0，E/O指数为3.2，肥度指数（E'）为2.28。评价结果表明，该水库已处于中度污染状态，水体处于中富营养化水平，NO3-、NO3-N、Cl-、COND、Depth、NH4+、TP和Chla是影响浮游动物种群数量及分布的主要环境因子，作为水源地其水质还需进一步加强管理与调控。 Abstract:During the summer of 2010, the zooplankton community structure and physicochemical factors of Xiquanyan Reservoir, China, were surveyed. Seven evaluation methods were used to assess water quality, including the standing crop index evaluation method, the biological indicator method, diversity analysis, QB/T index, eu-mesotrophic/oligo-mesotrophic (E/O) index, fertility index method (E'), and physical and chemical factors evaluation method. Simultaneously, a canonical correspondence analysis (CCA) was used to analyze the correlations between the zooplankton community structure and environmental factors.The results showed that 33 genera comprising 56 species of zooplankton were found, including protozoa (14 species), rotifers (29 species), cladocerans (4 species), and copepods (9 species). The variety and quantity of zooplankton were the greatest at S5, and those at S1 were the lowest. The ordination of variety and quantity of zooplankton at each sampling site was S5 > S4 > S9 > S8 > S6 > S2 > S7 > S3 > S1. Rotifers were dominant in variety and quantity, with larger numbers and more species in the middle of the reservoir compared with the estuary area. Fifty-three species were typical indicators of environmental pollution, including ignoreprobity (10 species), o-β mesosaprobity (5 species), β-mesosaprobity (15 species), β-α-mesosaprobity (7 species), and α-mesosaprobity (16 species). Common species were Polyarthra trigla, Macrocyclops albidus, Microcyclops javanus, and Mi. inchoatus. Dominant species were Difflugia avellana, Filinia longiseta, Polyarthra trigla, Mi. inchoatus, and nauplius. The average species richness was 46.13 ind./L. Site S4 had the highest species richness (84.5%), and S1 had the lowest (0.5%). Of the four types of zooplankton, rotifers had the highest, and cladocerans had the lowest abundance. The species richness of protozoa was 9.53 ind./L, with S4 having the highest and S1 the lowest. The species richness of rotifers was 32.48 ind./L, S4 had the highest and S8 the lowest. The species richness of cladocerans was 1.33 ind./L, S5 had the highest and S2 the lowest. The species richness of copepods was 2.79 ind./L, S5 had the highest and S1 was the lowest. The average biomass was 0.137 mg/L, S5 had the biomass (39.8%), and S1 had the lowest (0.6%). Copepods contributed the most to biomass, whereas protozoa had the least contribution. The average Shannon-Wiener index of Xiquanyan Reservoir was 2.78, and the pollution level was β-mesosaprobity; Margalef richness index was 1.97, and the pollution level was α-mesosaprobity. Xiquanyan Reservoir had 5 oligo-mesotrophic (O) and 16 eu-mesotrophic (E) zooplankton species. The calculations of the QB/T index, E/O index, and E' index were 2.0, 3.2, and 2.28, respectively. The water quality evaluation determined meso-eutrophic and eutrophic levels based on bio-physical and chemical indices. The meso-eutrophic level was determined by chlorophyll a, total phosphorus content (TP), and transparency indicators; and the eutrophication level was determined by total nitrogen (TN) and dissolved oxygen indicators. According to the CCA, the horizontal axis had an extremely significant positive correlation with NO3-(P=0.95), NO3--N(P=0.75), and Cl-(P=0.75), and the vertical axis had a significant positive correlation with NH4+(P=0.71), TP(P=0.68), Chl a(P=0.60), and had a significant negative correlation with depth (P=-0.72)and COND(P=-0.72). NO3-, NO3--N, Cl-, COND, depth, NH4+, TP, and Chl a were the main factors affecting the quantity and distribution of zooplankton populations, and TN had little correlation with zooplankton. From the results, the water quality of Xiquanyan Reservoir was moderately polluted, and the eutrophication level was average. As an alternative source of drinking water for Harbin city, the water quality still requires improvement, and the water management and regulation should be enhanced. 参考文献 相似文献 引证文献

LISTADO TAXONÓMICO DE COPÉPODOS (ARTHROPODA: CRUSTACEA) DEL MAR CARIBE COLOMBIANO

In the Colombian Caribbean there are few studies on zooplankton that have explored their specific composition and the existing information is largely restricted to grey literature. Studies in other areas of the Caribbean show a high species richness of copepods, recording approximately 500 species. This paper presents a taxonomic list of 217 species of planktonic copepods belonging to the orders Calanoida, Cyclopoida, Harpacticoida, Poecillostomatoida, Mormonilloida, and Siphonostomatoida recorded in the Colombian Caribbean since 1970.

Recovery of salt marsh benthic microalgae and meiofauna following the Deepwater Horizon oil spill linked to recovery of Spartina alterniflora

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 536:39-54 (2015) - DOI: https://doi.org/10.3354/meps11451 Recovery of salt marsh benthic microalgae and meiofauna following the Deepwater Horizon oil spill linked to recovery of Spartina alterniflora J. W. Fleeger1,*, K. R. Carman1,2, M. R. Riggio1, I. A. Mendelssohn3, Q. X. Lin3, A. Hou4, D. R. Deis5, S. Zengel6 1Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA 2Department of Biology, University of Nevada-Reno, Reno, Nevada 89557, USA 3Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA 4Department of Environmental Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA 5Atkins, 7406 Fullerton St., Jacksonville, Florida 32256, USA 6Research Planning, Inc. (RPI), 247 E. 7th Ave., Tallahassee, Florida 32303, USA *Corresponding author: zoflee@lsu.edu ABSTRACT: We examined the effects of the Deepwater Horizon oil spill on benthic microalgae and meiofauna in Louisiana, USA, salt marshes. Further, we quantified recovery over 4 yr and compared it to recovery of the dominant salt marsh macrophyte Spartina alterniflora. Although impacts were apparent at lightly and moderately oiled sites, negative effects on microalgal biomass and meiofaunal abundance and diversity were strongest in heavily oiled marshes where almost complete mortality of S. alterniflora occurred. However, these metrics, as well as photosynthetic pigment composition and meiofauna community composition, indicated substantial recovery ~36 mo post-spill, coincident with recovery of S. alterniflora stem density, even in heavily oiled marshes. Meiofaunal diversity (as measured by copepod species richness) in the earliest stages of recovery was highest where recovering S. alterniflora stems were most dense, and overall, meiofauna recovery was more closely linked to S. alterniflora than to vegetative recovery per se. However, for the polychaete Manayunkia aestuarina, ostracods and kinorhynchs, recovery was still ongoing 4 yr after the spill. These findings suggest that the important ecological services provided in support of food webs by benthic microalgae (a principal basal food resource) and meiofauna (a principal consumer of benthic microalgae and dietary resource to higher trophic levels) largely returned coincident with the recovery of S. alterniflora. S. alterniflora may therefore be a good indicator for the broader recovery of salt marsh infaunal benthos, at least in marshes without accelerated shoreline erosion induced by oiling. KEY WORDS: Deepwater Horizon oil spill · Meiofauna · Benthic microalgae · Salt marsh · ∙ Spartina alterniflora Full text in pdf format Supplementary material PreviousNextCite this article as: Fleeger JW, Carman KR, Riggio MR, Mendelssohn IA and others (2015) Recovery of salt marsh benthic microalgae and meiofauna following the Deepwater Horizon oil spill linked to recovery of Spartina alterniflora. Mar Ecol Prog Ser 536:39-54. https://doi.org/10.3354/meps11451 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 536. Online publication date: September 29, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Estimating cyclopoid copepod species richness and geographical distribution (Crustacea) across a large hydrographical basin: comparing between samples from water column (plankton) and macrophyte stands

Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the "La Plata" River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone.

Assessing copepod (Crustacea: Copepoda) species richness at different spatial scales in northwestern Romanian caves

The aim of the present study was to assess copepod species richness in groundwater habitats from the Pădurea Craiului Mountains, Transylvania (northwestern Romania). Five species richness estimators (one asymptotic, based on species accumulation curves, and four non-parametric) were compared by testing their performances in estimating copepod species richness at three hierarchical spatial scales: cave, hydrographic basin, and karstic massif. Both epigean and hypogean species were taken in account. Two data sets were used in computing copepod species richness: 1. samples collected continuously during one year (dripping water) and seven months (pools) from five caves, and 2. samples collected from pools in twelve additional caves (data gathered from literature). Differences in copepod species richness among caves and hydrographic basins suggest that local environmental features are important in determining local species richness trends.

The influence of phytoplankton productivity, temperature and environmental stability on the control of copepod diversity in the North East Atlantic

The patterns of copepod species richness (S) and their relationship with phytoplankton productivity, temperature and environmental stability were investigated at climatological, seasonal and year-to-year time scales as well as scales along latitudinal and oceanic–neritic gradients using monthly time series of the Continuous Plankton Recorder (CPR) Survey collected in the North East Atlantic between 1958 and 2006. Time series analyses confirmed previously described geographic patterns. Equatorward and towards neritic environments, the climatological average of S increases and the variance explained by the seasonal cycle decreases. The bi-modal character of seasonality increases equatorward and the timing of the seasonal cycle takes place progressive earlier equatorward and towards neritic environments. In the long-term, the climatological average of S decreased significantly (p<0.001) between 1958 and 2006 in the Bay of Biscay and North Iberian shelf at a rate of ca. 0.04year−1, and increased at the same rate between 1991 and 2006 in the northernmost oceanic location. The climatological averages of S correlate positively with those of the index of seasonality of phytoplankton productivity (ratio between the minimum and maximum monthly values of surface chlorophyll) and sea surface temperature, and negatively with those of the proxy for environmental stability (monthly frequency of occurrence of daily averaged wind speed exceeding 10ms−1). The seasonal cycles of S and phytoplankton productivity (surface chlorophyll as proxy) exhibit similar features in terms of shape, timing and explained variance, but the relationship between the climatological averages of both variables is non-significant. From year-to-year, the annual averages of S correlate negatively with those of phytoplankton productivity and positively with those of sea surface temperature along the latitudinal gradient, and negatively with those of environmental stability along the oceanic–neritic gradient. The annual anomalies of S (i.e. factoring out geographic variation) show a unimodal relationship with those of sea surface temperature and environmental stability, with S peaking at intermediate values of the anomalies of these variables. The results evidence the role of seasonality of phytoplankton productivity on the control of copepod species richness at seasonal and climatological scales, giving support to the species richness–productivity hypothesis. Although sea surface temperature (SST) is indeed a good predictor of richness along the latitudinal gradient, it is unable to predict the increase of richness form oceanic to neritic environments, thus lessening the generality of the species richness–energy hypothesis. Meteo-hydrographic disturbances (i.e. SST and wind speed anomalies as proxies), presumably through its role on mixed layer depth dynamics and turbulence and hence productivity, maximise local diversity when occurring at intermediate frequency and or intensity, thus providing support to the intermediate disturbance hypothesis on the control of copepod diversity.

Recovery of zooplankton diversity in a restored Mediterranean temporary marsh in Doñana National Park (SW Spain)

Over 30 years after drainage for agriculture, a 2700 ha temporary marshland was recently restored in Donana National Park. We describe the recovery of zooplankton communities (copepods, cladocerans and rotifers) in 47 new temporary ponds excavated as part of the restoration project during the first two hydroperiods (April 2006 and 2007), and compare them to those of eight reference sites in the surrounding marshland. Major changes in the species composition and abundance occurred in new ponds between years. While rotifers and cyclopoid copepods dominated in terms of number of individuals in 2006, calanoid copepods and cladocerans were the most abundant groups in 2007. Rotifer species richness was significantly lower in 2007, but there was an increase in Simpson and β-diversity in 2007 owing largely to a dramatic decline in the abundance of Hexarthra cf. fennica (rare in reference sites) from 93% of all rotifer individuals in new ponds in 2006 to only 32% in 2007. In contrast, species richness of copepods and cladocerans was significantly higher in new ponds in 2007, but there were no changes in Simpson diversity. β-Diversity of cladocerans was also significantly higher in 2007. In 2006, the species richness of cladocera and copepods was significantly lower in new ponds than in reference sites, but by 2007 there were no differences in richness or Simpson diversity. Overall, 7 copepod, 13 cladoceran and 26 rotifer taxa were recorded in new ponds, including 80% of taxa recorded in reference sites. These results indicate that zooplankton communities can be rapidly restored in Mediterranean temporary wetlands, at least when large source populations in the surrounding area reduce dispersal limitation. They also illustrate the importance of comparing different metrics of richness and diversity in studies of zooplankton restoration.

Mesozooplankton community in the Bay of Bengal (India): spatial variability during the summer monsoon

This study addresses the spatial variability in mesozooplankton biomass and composition in the Central and Western Bay of Bengal (India) during the summer monsoon season of 2001. Perennially warmer seasurface temperatures (> 28oC), stratified top layer (sea-surface salinity, 28-33 psu), high turbidity, and low nutrient concentrations due to weak/null upwelling and light limitation make the Bay of Bengal a region of low primary productivity. Despite this, mesozooplankton biomass values i.e. 2.9-104 mg C m -3 in the Central Bay and 1.3-31 mg C m -3 in the Western Bay observed in the mixed layer (2-51 m) during the summer monsoon were in the same range as reported from the more productive Arabian Sea. Mesozooplankton biomass was five times and density 18 times greater at stations with signatures of coldcore eddies, causing a higher spatial heterogeneity in zooplankton distribution. Among the 27 taxonomic groups recorded during the season, Copepoda was the most abundant group in all samples followed by Chaetognatha. The dominant order of Copepoda, Calanoida, was represented by 132 species in a total of 163 species recorded. Oncaea venusta was the key copepod species in the Bay. In the Central Bay, the predominant copepod species were carnivorous/omnivorous vis a vis most herbivores in the Western Bay. Pleuromamma indica increased to its maximum abundance at 18oN in the Central Bay, coinciding with the lowest dissolved oxygen concentrations. The Central Bay had higher mesozooplankton biomass, copepod species richness and diversity than in the Western Bay. Although zooplankton biomass and densities were greater at the eddy stations, correlation between zooplankton and chl a was not statistically significant. It appears that the grazer mesozooplankton rapidly utilize the enhanced phytoplankton production in coldcore eddies.

Caracterización cualitativa del zooplancton del Área de Conservación Marina Isla del Coco (ACMIC), Océano Pacífico de Costa Rica

Qualitative characterization of the zooplankton of the Cocos Island Marine Conservation Area (Area de Conservacion Marina Isla del Coco, ACMIC), Pacific Ocean of Costa Rica. During November 2001, zooplankton samples were obtained from sites around Isla del Coco, a protected oceanic island off the Pacific coast of Costa Rica. Vertical (0-50 m) and horizontal hauls were performed. This first qualitative analysis of the zooplankton shows a very diverse community, with copepods being dominant (68 species). Up to 19 species of Copepoda represent new records for Costa Rican Pacific waters and thus, increase the relative number of species recorded from Costa Rica in relation to the overall copepod species richness of the eastern tropical Pacific. Hyperiid amphipods were represented by 20 species; this is the first reference about this group from waters around Isla del Coco. Other planktic crustaceans recorded were Evadne sp. (Cladocera), Cypridina americana and Euconchoecia sp. (Ostracoda), and unidentified euphausiids and mysidaceans. Six families of planktic gastropods were found, including Limacinidae, Cavolinidae, Pneumodermopsidae, and Desmopteridae; heteropod molluscs were also collected (Pterotracheidae, Carinariidae and Atlantidae), and also the nudibranch Phylliroe bucephala (Phylliroidae). Seven species of chaetognaths were recorded, Flaccisagitta enflata and Serratosagitta pacifica being the commonest. Appendicularians (five species of Oikopleura and Stegosoma ) and salps ( Salpa sp. and Doliolum sp.) were also present in the samples. Pyrosomatida (Thaliacea) are first records for Costa Rican Pacific waters. The gelatinous zooplankton included seven species of siphonophores and three of medusae, Rhopalonema velatum being the most frequent medusa. Overall zooplankton species diversity (including ichthyoplankton) of Isla del Coco is lower, but not by much, than in the Costa Rica Dome (136 vs 178). Some ideas are discussed about the value of Isla del Coco as a zooplankton diversity hot spot. Rev. Biol. Trop. 56 (Suppl. 2): 159-169. Epub 2008 August 29.

Copepod (Crustacea) Emergence from Soils from Everglades Marshes with Different Hydroperiods

ABSTRACT During a severe drought period in the winter and spring of 1989, we made three collections of dried marsh soils from freshwater sloughs in Everglades National Park, Florida, at sites characterized by either long or intermediate annual periods of flooding (hydroperiod). After rehydrating the soils in aquaria, we documented the temporal patterns of copepod emergence over two-week periods. The species richness of copepods in the rehydrated soils was lower than in predrought samples from the same slough sites. Only six of the 16 species recorded from the Everglades emerged in the aquarium tests. The long hydroperiod site had a slightly different assemblage and higher numbers of most species than the intermediate-hydroperiod sites. More individuals and species emerged from the early dry-season samples compared with samples taken later in the dry season. The harpacticoid, Cletocamptus deitersi, and the cyclopoid, Microcyclops rubellus, were abundant at most sites. The cyclopoids—Ectocyclops phaleratus, Homocyclops ater, and Paracyclops chiltoni—are new records for the Everglades. We infer that 1) only a subset of Everglades copepod species can survive drought by resting in soils; and that 2) survival ability over time differs by species.

Analysis of the parasitic copepod species richness among Mediterranean fish

The Mediterranean ichthyofauna is composed of 652 species belonging to 405 genera and 117 families. Among these, 182 were studied for their parasitic copepods. The analysis of all the works conducted on these crustacea yielded 226 species distributed in 88 genera and 20 families. For each fish species we have established a file providing the species name of the fish, its family, its geographical distribution within the Mediterranean and some of its bio-ecological characteristics. Within each file, all the parasitic copepod species reported on each host species were listed. This allowed to know the species richness (SR) of these hosts. We thus produced 182 files within which 226 copepod species are distributed. A program was created under the Hypercard software, in order to analyse our data. Two parameters were studied. The first one is the mean species richness (MSR), which corresponds to the mean of the different SR found on the different host species. The second is the parasite–host ratio (P/H), which is the ratio of the number of copepod species by the number of host species. These parameters are calculated by our program for all the 182 species of Mediterranean fishes retained in our investigation, on the first hand, and, on the second hand, for one particular group of fish species. We used the following variables to investigate their correlations with copepod species richness: taxonomy—fish families, genera and species; biometry—maximal size of the adult fish; eco-ethology—mode of life (benthic, pelagic or nectonic), displacements (sedentary, migratory with environmental change, or migratory without environmental change), behaviour (solitary or gregarious). Other variables (colour, food, reproduction, abundance, distribution area) were also analysed but did not reveal any clear correlation. Providing that our study does not rely on quantitative (prevalence, intensity) but qualitative basis our aim was only to reveal some tendencies. These tendencies are as follows: (1) In many cases, parasite and host phylogeny seem to play an important role. There are fish families with copepods and families with few species of these parasites. The phyletic constraints could be due to the morphological characteristics of the habitat (e.g. structure of the gills) or biological/ecological characteristics that we were unable to identify. (2) It appears that the presence in a same environment of related fish species (e.g. several species of the same genus, or numerous genera of the same family) is correlated with high parasite richness. A likely explanation is that such situations favours alternated processes of lateral transfers and speciation. (3) Some eco-ethological criteria seem to favour the establishment of a large parasite species richness. It should be noted for instance that Mediterranean fishes the most often infected with copepods are generally nectonic or pelagic, migratory, and gregarious species.

Preliminary analysis of parasitic copepod species richness among coastal fishes of Tunisia

A total of 44 species belonging to 20 families, representing a broad diversity of marine fishes, were identified and examined from Tunisian inshore fisheries sampling efforts. A parasitological study of these fish species revealed a great diversity of their parasitic copepoda. About 53% of examined species were infected by at least one species of parasitic copepod. We report 38 parasite species belonging to seven families of which 17 are new record for Tunisia. Moreover, the diversity of the copepods parasite varied with host characteristics. The specificity of the copepods varied widely as well.