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1.
Environ Pollut ; 252(Pt B): 1483-1490, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265959

RESUMO

Biodiversity in running water ecosystems such as streams and rivers is threatened by chemical pollution derived from anthropogenic activities. Zooplankton are ecologically indicative in aquatic ecosystems, owing to their position of linking the top-down and bottom-up regulators in aquatic food webs, and thus of great potential to assess ecological effects of human-induced pollution. Here we investigated the influence of water pollution on zooplankton communities characterized by metabarcoding in Songhua River Basin in northeast China. Our results clearly showed that varied levels of anthropogenic disturbance significantly influenced water quality, leading to distinct environmental pollution gradients (p < 0.001), particularly derived from total nitrogen, nitrate nitrogen and pH. Redundancy analysis showed that such environmental gradients significantly influenced the geographical distribution of zooplankton biodiversity (R = 0.283, p = 0.001). In addition, along with the trend of increasing environmental pollution, habitat-related indicator taxa were shifted in constituents, altering from large-sized species (e.g. arthropods) in lightly disturbed areas to small-sized organisms (e.g. rotifers and ciliates) in highly disturbed areas. All these findings clearly showed that anthropogenic activity-derived water pollution significantly influenced biological communities. Thus, biotic consequences of human-induced environmental pollution in running water ecosystems should be deeply investigated. More importantly, the findings of biotic consequences should be well integrated into existing monitoring programs to further assess impacts of anthropogenic disturbance, as well as to advance the management of running water ecosystems for conservation and ecological restoration.


Assuntos
Biodiversidade , Monitoramento Ambiental , Rios/química , Poluentes Químicos da Água/análise , Poluição da Água/análise , Zooplâncton/crescimento & desenvolvimento , Animais , China , Ecossistema , Cadeia Alimentar , Humanos , Nitratos/análise , Nitrogênio/análise , Qualidade da Água , Zooplâncton/classificação
2.
Environ Pollut ; 251: 277-284, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31082612

RESUMO

A comparative limnological study of the zooplankton communities and their relationship with environmental factors was conducted to test the temporal and spatial changes among lake groups. In our study of four lakes, the lowest gamma (γ) diversity was recorded in January 2017, with a total of 25 zooplankton taxa. The highest γ diversity was recorded in May 2016, with a total of 55 zooplankton taxa. Species turnover in space (ß) were from 14.98 to 25.81. Markedly temporal and spatial variations were observed in the zooplankton community. The higher mean cladocera density (57.70 ind. L-1 and 39.85 ind. L-1) was observed in May and August, then decreased gradually with the lowest in January. The mean copepoda density ranged from 8.71 ind. L-1 in January 2017 to 32.04 ind. L-1 in August 2016. The mean rotifera density was significantly higher than that of the other two crustacean zooplankton (p < 0.01), within the range of 89.36-1139.2 ind. L-1. We also observed that zooplankton density exhibited significant seasonal changes from NMDS (Nonmetric multidimensional scaling analysis). Redundancy analysis revealed that environmental factors, such as water temperature and transparency, have significantly influenced the zooplankton community structure.


Assuntos
Cladóceros/classificação , Copépodes/classificação , Monitoramento Ambiental/métodos , Lagos/química , Rotíferos/classificação , Zooplâncton/classificação , Animais , Biodiversidade , China , Densidade Demográfica , Rios/química , Estações do Ano , Análise Espaço-Temporal , Temperatura Ambiente
3.
Environ Monit Assess ; 191(4): 201, 2019 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-30826892

RESUMO

Both environmental and geographic factors interact to structure the metacommunities in river networks, but the importance of these factors is difficult to distinguish. We used six aquatic taxonomic groups to test the relationship between environmental and geographic factors and their effect on species turnover patterns in an agriculturally dominated river (Chaohu Lake Basin, China). The relationships between three dissimilarity indices and geographic distance were assessed using the Mantel test while considering the differences in environmental factors between sites. Then, we employed a variation partitioning method to distinguish the isolated and combined effects of environmental and geographic distance on species turnover. There were significant relationships between environmental distance and species turnover in all groups. All organisms except periphytic diatoms were significantly correlated with two geographic (Euclidean and network) distances when the Chao dissimilarity index was considered. The results suggest that the strength of the correlations changed with environmental and geographic distances and with the aquatic community. The communities displayed more complex relationships with the distance measures when different dissimilarity (Jaccard, Chao, and Bray-Curtis dissimilarity) indices were considered. Nevertheless, aquatic communities are strongly influenced by both environmental and geographic distance, and the former has a stronger effect than the latter.


Assuntos
Biodiversidade , Diatomáceas/classificação , Monitoramento Ambiental , Peixes/classificação , Fitoplâncton/classificação , Rotíferos/classificação , Zooplâncton/classificação , Agricultura , Animais , China , Diatomáceas/isolamento & purificação , Geografia , Lagos , Fitoplâncton/isolamento & purificação , Rios , Rotíferos/isolamento & purificação , Zooplâncton/isolamento & purificação
4.
PLoS Genet ; 15(2): e1007943, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30735490

RESUMO

Marine ecosystems are changing rapidly as the oceans warm and become more acidic. The physical factors and the changes to ocean chemistry that they drive can all be measured with great precision. Changes in the biological composition of communities in different ocean regions are far more challenging to measure because most biological monitoring methods focus on a limited taxonomic or size range. Environmental DNA (eDNA) analysis has the potential to solve this problem in biological oceanography, as it is capable of identifying a huge phylogenetic range of organisms to species level. Here we develop and apply a novel multi-gene molecular toolkit to eDNA isolated from bulk plankton samples collected over a five-year period from a single site. This temporal scale and level of detail is unprecedented in eDNA studies. We identified consistent seasonal assemblages of zooplankton species, which demonstrates the ability of our toolkit to audit community composition. We were also able to detect clear departures from the regular seasonal patterns that occurred during an extreme marine heatwave. The integration of eDNA analyses with existing biotic and abiotic surveys delivers a powerful new long-term approach to monitoring the health of our world's oceans in the context of a rapidly changing climate.


Assuntos
Organismos Aquáticos/genética , Biodiversidade , Mudança Climática , Ecossistema , Animais , Organismos Aquáticos/classificação , DNA/genética , DNA/isolamento & purificação , Código de Barras de DNA Taxonômico , Monitoramento Ambiental , Oceanos e Mares , Filogenia , Estações do Ano , Austrália Ocidental , Zooplâncton/classificação , Zooplâncton/genética
5.
Environ Pollut ; 245: 1050-1057, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30682739

RESUMO

Monitoring diverse components of aquatic ecosystems is vital for elucidation of diversity dynamics and processes, which alter freshwater ecosystems, but such studies are seldom conducted. Phytoplankton and zooplankton are integral components which play indispensable parts in the structure and ecological service function of water bodies. However, few studies were made on how zooplankton and phytoplankton community may respond simultaneously to change of circumstance and their mutual relationship. Therefore, we researched synchronously the phytoplankton communities as well as zooplankton communities based on monthly monitoring data from September 2011 to August 2012 in heavily polluted areas and researched their responses to variation in environmental parameters and their mutual relationship. As indicated by Time-lag analysis (TLA), the long-term dynamics of phytoplankton and zooplankton were undergoing directional variations, what's more, there exists significant seasonal variations of phytoplankton and zooplankton communities as indicated by Non-Metric Multidimensional scaling (NMDS) methods. Also, Redundancy Analysis (RDA) demonstrated that environmental indicators together accounted for 25.6% and 50.1% variance of phytoplankton and zooplankton, respectively, indicating that environmental variations affected significantly on the temporal dynamics of phytoplankton as well as zooplankton communities. What's more, variance partioning suggested that the major environmental factors influencing variation structures of zooplankton communities were water temperature, concentration of nitrogen, revealing the dominating driving mechanism which shaped the communities of zooplankton. It was also found that there was significant synchronization between zooplankton biomass and phytoplankton biomass (expressed as Chl-a concentration), which suggested that zooplankton respond to changes in dynamic structure of phytoplankton community and can initiate a decrease in phytoplankton biomass through grazing in a few months.


Assuntos
Monitoramento Ambiental/métodos , Lagos/química , Fitoplâncton/crescimento & desenvolvimento , Qualidade da Água , Zooplâncton/crescimento & desenvolvimento , Animais , Biodiversidade , Biomassa , China , Nitrogênio/análise , Fitoplâncton/classificação , Estações do Ano , Temperatura Ambiente , Poluentes Químicos da Água/análise , Zooplâncton/classificação
6.
Mitochondrial DNA A DNA Mapp Seq Anal ; 30(1): 118-125, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29671658

RESUMO

Ostracods (Crustacea, Ostracoda) are small bivalved crustaceans, contributing over 200 described species to the marine zooplankton community. They are widely distributed and are relatively abundant components of the mesozooplankton, playing an important role in the transport of organic matter to deep layers. However, identification of ostracods based on micro-morphological characters is extremely difficult and time-consuming. Previous fragmentary taxonomic studies of ostracods in the South China Sea (SCA), were based solely on morphology. Here, by analysing the mitochondrial COI gene, we explore the taxa across the SCA using molecular tools for the first time. Our results show that sequence divergence among species varies within a large range, from 12.93% to 35.82%. Sixteen of the taxonomic units recovered by DNA taxonomy agree well with morphology, but Paraconchoecia oblonga, Conchoecia magna and Halocypris brevirostris split into two clades each, each of which contains cryptic species.


Assuntos
Biodiversidade , Crustáceos/genética , Código de Barras de DNA Taxonômico/métodos , Filogenia , Zooplâncton/genética , Animais , Crustáceos/classificação , Código de Barras de DNA Taxonômico/normas , Complexo IV da Cadeia de Transporte de Elétrons/genética , Zooplâncton/classificação
7.
Mar Pollut Bull ; 147: 16-35, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29454492

RESUMO

Ballast water discharges may cause negative impacts to aquatic ecosystems, human health and economic activities by the introduction of potentially harmful species. Fifty untreated ballast water tanks, ten in each port, were sampled in four Adriatic Italian ports and one Slovenian port. Salinity, temperature and fluorescence were measured on board. Faecal indicator bacteria (FIB), phyto- and zooplankton were qualitatively and quantitatively determined to identify the species assemblage arriving in ballast water. FIB exceeded the convention standard limits in 12% of the sampled tanks. Vibrio cholerae was not detected. The number of viable organisms in the size groups (minimum dimension) <50 and ≥10 µm and ≥50 µm resulted above the abundances required from the Ballast Water Management Convention in 55 and 86% of the samples, respectively. This is not surprising as unmanaged ballast waters were sampled. Some potentially toxic and non-indigenous species were observed in both phyto- and zooplankton assemblages.


Assuntos
Fitoplâncton , Navios , Zooplâncton , Animais , Organismos Aquáticos , Bactérias , Ecossistema , Fezes/microbiologia , Espécies Introduzidas , Mar Mediterrâneo , Fitoplâncton/classificação , Salinidade , Inquéritos e Questionários , Temperatura Ambiente , Água/química , Microbiologia da Água , Zooplâncton/classificação
8.
Microb Ecol ; 77(2): 277-287, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29951743

RESUMO

Bacterioplankton are both primary producers and primary consumers in aquatic ecosystems, which were commonly investigated to reflect environmental changes, evaluate primary productivity, and assess biogeochemical cycles. However, there is relatively less understanding of their responses to anthropogenic disturbances such as constructions of dams/tunnels/roads that may significantly affect the aquatic ecosystem. To fill such gap, this study focused on the bacterioplankton communities' diversity and turnover during a tunnel construction across an urban lake (Lake Donghu, Wuhan, China), and five batches of samples were collected within 2 months according to the tunnel construction progress. Results indicated that both resources and predator factors contributed significant to the variations of bacterioplankton communities, but the closed area and open areas showed different diversity patterns due to the impacts of tunnel construction. Briefly, the phytoplankton, TN, and TP in water were still significantly correlated with the bacterioplankton composition and diversity like that in normal conditions. Additionally, the organic matter, TN, and NH4-N in sediments also showed clear effects on the bacterioplankton. However, the predator effects on the bacterioplankton in the closed-off construction area mainly derived from large zooplankton (i.e., cladocerans), while small zooplankton such as protozoa and rotifers are only responsible for weak predator effects on the bacterioplankton in the open areas. Further analysis about the ecological driving forces indicated that the bacterioplankton communities' turnover during the tunnel construction was mainly governed by the homogeneous selection due to similar environments within the closed area or the open areas at two different stages. This finding suggests that bacterioplankton communities can quickly adapt to the environmental modifications resulting from tunnel construction activities. This study can also give references to enhance our understanding on bacterioplankton communities' response to ecological and environmental changes due to intensification of construction and urbanization in and around lake ecosystems.


Assuntos
Bactérias/isolamento & purificação , Lagos/microbiologia , Plâncton/isolamento & purificação , Animais , Bactérias/classificação , Bactérias/genética , Biodiversidade , China , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/parasitologia , Lagos/parasitologia , Filogenia , Plâncton/classificação , Plâncton/genética , Zooplâncton/classificação , Zooplâncton/genética , Zooplâncton/isolamento & purificação
9.
Ying Yong Sheng Tai Xue Bao ; 29(9): 3078-3084, 2018 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-30411585

RESUMO

Based on the data of zooplankton samples from 27 stations in the offshore area of Changjiang Estuary in August 2016, we analyzed the community structure and diversity of zooplankton and examined the relationship between zooplankton community structure and environmental factors. A total of 108 species of zooplankton belonging to 12 groups in six phyla, together with 15 types of pelagic larvae and fish eggs were identified. The main groups were copepods, thaliacea, chaetognaths, cladocladus and medusae, with the average abundance being 273.9, 115.0, 67.1, 63.6 and 61.1 ind·m-3. The most dominant group of zooplankton was copepods (48 species), accounting for 44.4% of the total zooplankton abundance. Medusae ranked second with a total of 12 species, accounting for 11.1% of the total zooplankton abundance. Furthermore, the absolute dominant group was copepods, with the highest contribution to the zooplankton community (20.3%). According to the clustering results of environmental factors, the area could be divided into Changjiang diluted water and offshore water mass. The results of analysis of similarities showed that the difference of zooplankton community between the two regions was significant (the average diffe-rence was 4%), and the contribution to the difference was 20.3%, 18.0%, 14.1%, 13.4%, and 11.8% for copepod, thaliacea, cladocera, chaetognaths, and medusae, respectively.


Assuntos
Estuários , Zooplâncton/classificação , Animais , China , Copépodes , Estações do Ano , Zooplâncton/crescimento & desenvolvimento
10.
Artigo em Inglês | MEDLINE | ID: mdl-30347725

RESUMO

Rivers and reservoirs in urban areas have been associated with environmental quality problems because of the discharge of domestic waste into water bodies. However, the key effects and the extent to which environmental factors can influence the integrated structure and function of urban river ecosystems remain largely unknown. Here, a relationship model involving the species composition of the community and the various environmental factors related to the water and sediment was developed in the dry season (N) and the flood season (F) in both the urban Jiaomen River (JR) and the Baihuitian Reservoir (BR) of Guangzhou City. Canonical correspondence analysis was used to determine the spatiotemporal drivers of the phytoplankton, zooplankton and macrobenthic communities in the river and reservoir systems. The combination of the thermodynamic-oriented ecological indicators and the biodiversity measures reflected the integrated structure and function of the ecosystems. Overall, the plankton community composition was found to be largely determined by the nutrient concentrations and oxygen index, and the development of the macrobenthic communities was mainly restricted by organic matter and heavy metals. Based on the results of the integrated assessment, the structure and function of the JR ecosystem were superior to that of the BR, and the F period displayed healthier results than the N period. Moreover, the structural and functional statuses of the high eco-exergy grade communities (macrobenthic communities) in the ecosystem influenced the regional changes observed in the results of the integrated assessment. The significant seasonal variations in the plankton community affected the seasonal variations in the integrated assessment. The results of this study provide a scientific basis for the management and restoration of regional freshwater environments and ecosystems.


Assuntos
Organismos Aquáticos/classificação , Biodiversidade , Ecossistema , Lagos , Rios , Animais , China , Cidades , Modelos Teóricos , Fitoplâncton/classificação , Zooplâncton/classificação
11.
Environ Monit Assess ; 190(10): 603, 2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30242488

RESUMO

The present study was conducted during July 2013 (early phase of monsoon or EM) and September 2013 (later phase of monsoon or LM) to ascertain the intra-monsoonal variation on zooplankton, by selecting 15 study stations in the river Saptamukhi, one of the main estuaries in the Sundarbans Estuarine System (SES). In 2013, SES experienced an unusually high monsoonal rainfall also exacerbated by cloud burst event at Himalayan region (upper stretches of SES) which tremendously increased the river runoff. The present work was aimed to decipher the effect of this unusual precipitation during the monsoon season on zooplankton assemblages along with different hydrological parameters. The abundance of zooplankton was recorded as lower during EM compared to LM. Altogether, 56 zooplankton taxa were identified with copepods forming the predominant population. Thirty-three copepod species were reported with 25 calanoid species forming the bulk of the biomass followed by 5 and 3 species of cyclopoids and harpacticoid, respectively. A combination of multivariate cluster analysis, biotic indices, and canonical correspondence analysis revealed noticeable alterations in the zooplankton community structure across the spatio-temporal scale. Furthermore, significant intra-monsoonal changes in zooplankton population correlated with several hydrological parameters were clearly noticed. Paracalanus parvus, Bestiolina similis and Oithona similis were observed to be the most dominant copepod species in both sampling periods. The result of the present study provides new insight on estuarine zooplankton community after unusual rainfall during monsoon season, and provides further evidence to support the conservation and management of the SES ecosystem.


Assuntos
Copépodes/classificação , Monitoramento Ambiental/métodos , Estuários , Zooplâncton , Animais , Biomassa , Ecossistema , Índia , Chuva , Estações do Ano , Zooplâncton/classificação , Zooplâncton/crescimento & desenvolvimento , Zooplâncton/isolamento & purificação
12.
Sci Rep ; 8(1): 12085, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30108256

RESUMO

Zooplankton plays a pivotal role in marine ecosystems and the characterisation of its biodiversity still represents a challenge for marine ecologists. In this study, mesozooplankton composition from 46 samples collected in summer along the western Adriatic Sea, was retrieved by DNA metabarcoding analysis. For the first time, the highly variable fragments of the mtDNA COI and the V9 region of 18S rRNA genes were used in a combined matrix to compile an inventory of mesozooplankton at basin scale. The number of sequences retrieved after quality filtering were 824,148 and 223,273 for COI and 18S (V9), respectively. The taxonomical assignment against reference sequences, using 95% (for COI) and 97% (for 18S) similarity thresholds, recovered 234 taxa. NMDS plots and cluster analysis divided coastal from offshore samples and the most representative species of these clusters were distributed according to the dominant surface current pattern of the Adriatic for the summer period. For selected sampling sites, mesozooplankton species were also identified under a stereo microscope providing insights on the strength and weakness of the two approaches. In addition, DNA metabarcoding was shown to be helpful for the monitoring of non-indigenous marine metazoans and spawning areas of commercial fish species. We defined pros and cons of applying this approach at basin scale and the benefits of combining the datasets from two genetic markers.


Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico/métodos , Monitorização de Parâmetros Ecológicos/métodos , Metagenômica/métodos , Zooplâncton/genética , Animais , DNA Mitocondrial/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Espécies Introduzidas , Biologia Marinha/métodos , Metagenoma/genética , Oceanos e Mares , RNA Ribossômico 18S/genética , Análise de Sequência de DNA/métodos , Zooplâncton/classificação
13.
Huan Jing Ke Xue ; 39(5): 2368-2379, 2018 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965538

RESUMO

Eukaryotic micro-plankton plays a key role in the marine biotic community and in maintaining the stability of the marine ecosystem. In order to determine the diversity and characteristics of eukaryotic micro-plankton in the Yellow Sea, Illumina high-throughput sequencing, based on gene markers of ITS, was conducted. An analysis of the relationship between community structure and environmental factors was conducted as well. The results are summarized in the following. ① Various of species of fungi, phytoplankton, and zooplankton were obtained by high-throughput sequencing technology; for OTUs, the order is fungi > phytoplankton > zooplankton, and for reads, the order is fungi > zooplankton > phytoplankton. ② In different waters, species abundance and diversity differed from each other. The Ace index and Chao1 index demonstrated an ordering of southern Yellow Sea > northern Yellow Sea > northern East Sea > Cold Water Mass; however, for the Simpson index and Shannon-Wiener index, the tendency followed the order of northern East Sea > northern Yellow Sea > southern Yellow Sea > Cold Water Mass. Species abundance and diversity in the Cold Water Mass were lowest. ③ The reads and OTUs of fungi, phytoplankton, and zooplankton increased as temperature rose. The reads and OTUs of fungi increased as salinity increased, while there was an opposite trend for phytoplankton and zooplankton. Latitude was another significant factor. In the range of 30° to 40° north latitude, the Shannon-Wiener index for fungi and zooplankton indicated an increasing tendency with an increase in latitude, while the Shannon-Wiener index for phytoplankton showed an opposite trend. With a greater distance from the coast, the Shannon-Wiener index of fungi, phytoplankton and zooplankton was lower. This is the first study that amplifies the use ITS in the research of marine eukaryotic micro-plankton, giving an enriched understanding of eukaryotic micro-plankton. The feasibility of applying high-throughput sequencing technology in the sea is proven, and this will provide a reference for other researchers.


Assuntos
Fungos/classificação , Fitoplâncton/classificação , Água do Mar/microbiologia , Zooplâncton/classificação , Animais , China , DNA Espaçador Ribossômico/genética , Ecossistema , Sequenciamento de Nucleotídeos em Larga Escala , Oceanos e Mares
14.
J Phycol ; 54(4): 557-570, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29908074

RESUMO

Some diatoms are able to colonize as epibionts on their potential zooplankton predators. Here, we report Pseudohimantidium pacificum living on the copepod Corycaeus giesbrechti and as a new finding on Oithona nana, Protoraphis atlantica living on the copepod Pontellopsis brevis, Protoraphis hustedtiana on the cypris larvae of barnacles, and Falcula hyalina on the copepod Acartia lilljeborgii. The epizoic diatoms were able to grow as free-living forms under culture conditions. Pseudohimantidium pacificum and P. atlantica appeared as the most derived species from their benthic diatom ancestors. The mucilage pad or stalk of the strains of these species showed important morphological distinction when compared with their epizoic forms. Barnacle larvae explore benthic habitats before settlement, and epibiosis on them is an example where P. hustedtiana profits from the host behavior for dispersal of its benthic populations. Molecular phylogenies based on the SSU rRNA and RuBisCO large subunit (rbcL) gene sequences revealed F. hyalina as an independent lineage within the Fragilariales (Tabularia, Catacombas, and others), consistent with its morphological distinction in the low number of rows (≤6) in the ocellulimbus, among other features. We propose the transfer of F. hyalina to the genus Pseudofalcula gen. nov. Molecular phylogeny suggests a single order for the members of the Cyclophorales and the Protoraphidales, and that the epibioses of araphid diatoms on marine zooplankton have been independently acquired several times. These clades are constituted of both epizoic and epiphytic/epilithic forms that evidence a recent acquisition of the epizoic modus vivendi.


Assuntos
Diatomáceas/classificação , Zooplâncton/classificação , Animais , DNA Ribossômico/análise , Diatomáceas/citologia , Diatomáceas/genética , Diatomáceas/ultraestrutura , Microscopia Eletrônica de Varredura , Filogenia , Fitoplâncton/classificação , Fitoplâncton/citologia , Fitoplâncton/genética , Fitoplâncton/ultraestrutura , Ribulose-Bifosfato Carboxilase/análise , Zooplâncton/citologia , Zooplâncton/genética , Zooplâncton/ultraestrutura
15.
J Environ Radioact ; 192: 14-25, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29883873

RESUMO

Water bodies polluted by the Mayak nuclear plant in Russia provide valuable information on multi-generation effects of radioactive contamination on freshwater organisms. For example, lake Karachay was probably the most radioactive lake in the world: its water contained ∼2 × 107 Bq/L of radionuclides and estimated dose rates to plankton exceeded 5 Gy/h. We performed quantitative modeling of radiation effects on phytoplankton and zooplankton species richness and abundance in Mayak-contaminated water bodies. Due to collinearity between radioactive contamination, water body size and salinity, we combined these variables into one (called HabitatFactors). We employed a customized machine learning approach, where synthetic noise variables acted as benchmarks of predictor performance. HabitatFactors was the only predictor that outperformed noise variables and, therefore, we used it for parametric modeling of plankton responses. Best-fit model predictions suggested 50% species richness reduction at HabitatFactors values corresponding to dose rates of 104-105 µGy/h for phytoplankton, and 103-104 µGy/h for zooplankton. Under conditions similar to those in lake Karachay, best-fit models predicted 81-98% species richness reductions for various taxa (Cyanobacteria, Bacillariophyta, Chlorophyta, Rotifera, Cladocera and Copepoda), ∼20-300-fold abundance reduction for total zooplankton, but no abundance reduction for phytoplankton. Rotifera was the only taxon whose fractional abundance increased with contamination level, reaching 100% in lake Karachay, but Rotifera species richness declined with contamination level, as in other taxa. Under severe radioactive and chemical contamination, one species of Cyanobacteria (Geitlerinema amphibium) dominated phytoplankton, and rotifers from the genus Brachionus dominated zooplankton. The modeling approaches proposed here are applicable to other radioecological data sets. The results provide quantitative information and easily interpretable model parameter estimates for the shapes and magnitudes of freshwater plankton responses to a wide range of radioactive contamination levels.


Assuntos
Biodiversidade , Monitoramento Ambiental , Modelos Estatísticos , Fitoplâncton/crescimento & desenvolvimento , Zooplâncton/crescimento & desenvolvimento , Animais , Clorófitas , Cladóceros , Ecossistema , Água Doce , Fitoplâncton/classificação , Radioatividade , Rotíferos , Federação Russa , Estações do Ano , Poluentes Radioativos da Água , Zooplâncton/classificação
16.
Sci Total Environ ; 627: 812-821, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29426206

RESUMO

The Gulf of Tadjoura is located in the Horn of Africa and is widely recognized as an important site where the zooplanktivorous whale sharks seasonally aggregate from October to February. The surface zooplankton community (0-3m) was weekly sampled from November 2016 to February 2017 in two sites during the whale shark aggregation period. A total of 12 phyla were identified. Copepoda represented the most abundant and diverse group with 29 different genera, and contributed with an average of 82% of the mean zooplankton density of approximately 6600indm-3. During the sampling period, copepods were dominated numerically by Calanoida (3600indm-3), followed by Poicilostomatatoida (1300indm-3). Within the copepods, Paracalanidae, Calanidae, Oncaeidae and Miraciidae were the most common families. The temporal trend in zooplankton biomass at both stations revealed the highest peak in December (41.3±36.4mgm-3), and the lowest in February (6.6±3.3mgm-3). As no information is available on the occurrence of legacy contaminants use and release in this area, analysis revealed the consistent presence of both DDT and PCB residues in zooplankton samples in the Gulf of Tadjoura. Total PCB ranged from approximately 110 to 637ngg-1 d.w., while total DDT from 21 to 80ngg-1 d.w. The proportion of primary DDT in the total residue was higher than DDE and DDD, which strongly suggests that the area might actually be subjected to DDT inputs of the parent compound.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/toxicidade , Zooplâncton/classificação , África , Animais , Biodiversidade , Copépodes , Djibuti , Água do Mar/química , Tubarões , Poluentes Químicos da Água/análise , Zooplâncton/crescimento & desenvolvimento
17.
Environ Monit Assess ; 190(3): 143, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29450746

RESUMO

Dissimilar life features of Rotifera, Cladocera and Copepoda enable these organisms to respond differently to changes in the hydrological regime which influence alterations in environmental characteristics. We investigated the effect of habitat heterogeneity (e.g. eupotamal, parapotamal, palaeopotamal) on individual zooplankton group assemblages and biodiversity indices (α, ß and γ diversity) during hydro regime change in floodplain waterbodies. Dissolved oxygen and organic nitrogen concentrations changed significantly among hydrological states while water depth was affected by both site and hydro regime replacement. Each studied site supported different zooplankton assemblage that highly depended on species-specific responses to hydro regime change. Also, individual zooplankton groups exhibited different correlations with specific environmental parameters regarding site change. Throughout the study, rotifers' local (α) and among-community (ß) diversities were susceptible to the site and inundation change while the microcrustacean biodiversity pattern diverged. Copepods highly discriminated different habitat types and hydrological phases at the regional scale (γ diversity), while we found a complete lack of biodiversity dependence on both site and hydrology for Cladocera. Our results show that heterogeneous environments support the development of different zooplankton assemblages that express the within-group dissimilarities. They also point to the importance of identifying processes in hydrologically variable ecosystems that influence biodiversity patterns at an individual zooplankton group level. Our results suggest the use of appropriate zooplankton groups as biological markers in natural habitats and stress the importance of proper management in preserving biodiversity in floodplain areas.


Assuntos
Ecossistema , Monitoramento Ambiental/métodos , Rios/química , Movimentos da Água , Zooplâncton , Animais , Biodiversidade , Cladóceros/classificação , Copépodes/classificação , Croácia , Hidrologia , Rotíferos/classificação , Estações do Ano , Especificidade da Espécie , Zooplâncton/classificação
18.
Nat Commun ; 9(1): 373, 2018 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-29371626

RESUMO

While our knowledge about the roles of microbes and viruses in the ocean has increased tremendously due to recent advances in genomics and metagenomics, research on marine microbial eukaryotes and zooplankton has benefited much less from these new technologies because of their larger genomes, their enormous diversity, and largely unexplored physiologies. Here, we use a metatranscriptomics approach to capture expressed genes in open ocean Tara Oceans stations across four organismal size fractions. The individual sequence reads cluster into 116 million unigenes representing the largest reference collection of eukaryotic transcripts from any single biome. The catalog is used to unveil functions expressed by eukaryotic marine plankton, and to assess their functional biogeography. Almost half of the sequences have no similarity with known proteins, and a great number belong to new gene families with a restricted distribution in the ocean. Overall, the resource provides the foundations for exploring the roles of marine eukaryotes in ocean ecology and biogeochemistry.


Assuntos
Organismos Aquáticos , Eucariotos/genética , Células Eucarióticas/metabolismo , Metagenoma , Filogenia , Zooplâncton/genética , Sequência de Aminoácidos , Animais , Atlas como Assunto , Bactérias/classificação , Bactérias/genética , Biodiversidade , Ecossistema , Eucariotos/classificação , Células Eucarióticas/citologia , Metagenômica/métodos , Oceanos e Mares , Fitoplâncton/classificação , Fitoplâncton/genética , Água do Mar , Vírus/classificação , Vírus/genética , Zooplâncton/classificação
19.
Environ Sci Pollut Res Int ; 25(10): 9992-9997, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29376215

RESUMO

Surface waters are likely to be contaminated by both pesticides and fertilizers. Such contamination can result in changes in community composition if there is differential toxicity to individual taxa. We conducted a fully factorial mesocosm experiment that examined the single and interactive effects of environmentally realistic concentrations of nitrate and malathion on zooplankton communities and phytoplankton productivity. Malathion significantly decreased the abundance of total zooplankton, cyclopoid copepods, copepod nauplii, and Ceriodaphnia, and increased the abundance of rotifers. Nitrate addition generally had no effect on zooplankton; however, Ceriodaphnia abundance was higher in control mesocosms than in nitrate-treated mesocosms. There was only one significant interaction between malathion and nitrate treatments: For Ceriodaphnia, the no malathion, no nitrate mesocosms had much higher abundances than all other combinations of treatments. Without nitrate addition, chl a levels were uniformly low across all malathion treatments, whereas in the presence of nitrate, there were differences among the malathion treatments. In conclusion, our results demonstrate that malathion contamination of aquatic ecosystems can result in changes in the abundance and composition of zooplankton communities. In contrast, nitrate contamination appeared to have much less potential impact on zooplankton communities, either on its own or in interaction with malathion. Our results reinforce the notion that the effects of contaminants on aquatic ecosystems can be complex and further research examining the single and interactive effects of chemical stressors is needed to more fully understand their effects.


Assuntos
Malation/toxicidade , Modelos Teóricos , Nitratos/toxicidade , Fitoplâncton/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Zooplâncton/efeitos dos fármacos , Animais , Ecossistema , Fertilizantes/toxicidade , Praguicidas/toxicidade , Fitoplâncton/classificação , Zooplâncton/classificação
20.
J Parasitol ; 104(1): 101-105, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29135342

RESUMO

The top-down effects of consumers, such as predators, are known to affect abundances, size structure, and species composition in aquatic ecosystems. Parasites are also important in shaping the ecology of free-living species; however, their effects are often overlooked because parasites can be difficult to detect. Parasites can be particularly challenging to observe in zooplankton hosts because of their small size and ephemeral infection periods. To overcome these challenges, we used a quarantine approach combined with high-magnification microscopy to increase detection of parasites of the tropical Cladoceran, Ceriodaphnia cornuta, in Lake Gatun, Panamá. Using this approach, we were able to demonstrate that competing morphs of Ceriodaphnia experience differential rates of infection, where the subordinate competitor suffered higher parasite prevalence than did the dominant morph. Predation by fishes on the dominant morph is considered the principal mechanism for their coexistence, but we hypothesize that parasites may also play a role in maintaining morphotype diversity of Ceriodaphnia.


Assuntos
Cladóceros/parasitologia , Lagos/parasitologia , Zooplâncton/crescimento & desenvolvimento , Animais , Cladóceros/anatomia & histologia , Cladóceros/classificação , Peixes/fisiologia , Interações Hospedeiro-Parasita , Modelos Lineares , Panamá , Comportamento Predatório/fisiologia , Zooplâncton/classificação
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