Xu J.,CAS East China Sea Fisheries Research Institute |
Liu S.,East China Sea Environmental Monitoring Center |
Xu Z.,CAS East China Sea Fisheries Research Institute |
Sun L.,CAS East China Sea Fisheries Research Institute |
Chen J.,CAS East China Sea Fisheries Research Institute
Chinese Journal of Applied and Environmental Biology | Year: 2014
For a comprehensive understanding of the interactive relationships of zooplankton ecogroups and their response to the changing water masses, the species composition and horizontal distribution of zooplankton in the Sansha Bay was analyzed to study the effect of water masses on the salinity adaptation of zooplankton. Distribution of zooplankton were investigated from samples collected from 10 stations during 5 oceanographic cruises in April, May, June, August and October in the Sansha Bay. All together 71 species were identified, including 36 nearshore species and 34 offshore species. The result showed significant differences in structures of ecogroups among months. In April and May, the nearshore species accounted for more than 97% of the total zooplankton abundances for all stations. The ambient water was influenced by the continental fresh runoff and the Zhemin Coastal Current, both with low salinity. From June to October, the abundance percentage of nearshore species fluctuated between 40.07% and 82.88%. There were significant differences between the two characteristic zooplankton communities in the northwestern and southeastern parts of the Bay, probably due to the effect of the Taiwan Warm Current. The northwestern part was characterized by high proportions of nearshore species in both number and abundance. The outer Bay of the southeastern part was characterized by relatively high proportions of offshore species in number and abundance. Our research revealed that the salinity adaptation and the temporal and spatial distribution of zooplankton are closely related to the currents changing with season.
Yang S.,East China Sea Environmental Monitoring Center |
Yang F.,Dalian University of Technology
Journal of Hazardous Materials | Year: 2011
An intermittently aerated moving bed membrane bioreactor (MBMBR) was developed and crucial parameters affecting nitrogen removal from wastewater by simultaneous nitrification and denitrification via nitrite were investigated, without strict control of solids retention time. Changes in the microbiological community and distribution in the reactor were monitored simultaneously. The intermittent-aeration strategy proved effective in achieving nitrition and the chemical oxygen demand (COD) to total nitrogen (TN) ratio was an important factor affecting TN removal. In the MBMBR, the nitrite accumulation rate reached 79.4% and TN removal efficiency averaged at 87.8% with aeration 2. min/mix 4. min and an influent COD/TN ratio of 5. Batch tests indicated that under the intermittently aerated mode, nitrite-oxidizing bacteria (NOB) were not completely washed out from the reactor but NOB activity was inhibited. The intermittently aerated mode had no effect on the activities of ammonia-oxidizing bacteria. Fluorescence in situ hybridizations (FISH) results also suggested that NOBs remained within the system. © 2011 Elsevier B.V.
Gao B.-B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research |
Gao B.-B.,University of Chinese Academy of Sciences |
Wang J.-F.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research |
Fan H.-M.,East China Sea Environmental Monitoring Center |
And 3 more authors.
International Journal of Geographical Information Science | Year: 2015
An efficient monitoring network is very important in accessing the marine environmental quality and its protection and management. In an estuary, there are fronts that separate distinctly different water masses and affect material transport, nutrient distribution, pollutant aggregation, and diffusion. This stratified heterogeneous surface neither satisfies the stationary requirements of kriging, nor can be handled adequately by removing a spatially continuous trend. This article presents a stratified optimization method for a multivariate monitoring network. In this method, principal component analysis (PCA) was used to reduce the dimensionality of the correlated targets, and the mean of surface with nonhomogeneity (MSN) method was adopted to produce the best linear unbiased estimator for a spatially stratified heterogeneous surface that failed to satisfy the requirements for a kriging estimate. The existing monitoring network in the Yangtze River estuary and its adjacent sea, which was designed by purposive sampling year ago was optimized as an illustration. The optimization consisted of two steps: reduce the redundant monitoring sites and then optimally add new sites to the remaining sites. After optimization, the inclusion of 51 sites in the monitoring network was found to produce a smaller total estimated error than that of the current network, which has 70 sites; moreover, the use of 55 sites can produce a higher precision of estimation for all three principal components (PCs) than that of the current 70 sites. The results demonstrated that the proposed method is suitable for optimizing environmental monitoring sites that have dominant stratified nonhomogeneity and that involve multiple factors. © 2015 Taylor & Francis.
Genovesi B.,Japan National Research Institute of Fisheries And Environment of Inland Sea |
Genovesi B.,Montpellier University |
Berrebi P.,Montpellier University |
Nagai S.,Japan National Research Institute of Fisheries And Environment of Inland Sea |
And 5 more authors.
Marine Pollution Bulletin | Year: 2015
The intra-specific diversity and genetic structure within the Alexandrium pacificum Litaker (A. catenella - Group IV) populations along the Temperate Asian coasts, were studied among individuals isolated from Japan to China. The UPGMA dendrogram and FCA revealed the existence of 3 clusters. Assignment analysis suggested the occurrence of gene flows between the Japanese Pacific coast (cluster-1) and the Chinese Zhejiang coast (cluster-2). Human transportations are suspected to explain the lack of genetic difference between several pairs of distant Japanese samples, hardly explained by a natural dispersal mechanism. The genetic isolation of the population established in the Sea of Japan (cluster-3) suggested the existence of a strong ecological and geographical barrier. Along the Pacific coasts, the South-North current allows limited exchanges between Chinese and Japanese populations. The relationships between Temperate Asian and Mediterranean individuals suggested different scenario of large-scale dispersal mechanisms. © 2015.
He Y.,Indiana University Bloomington |
He Y.,East China Normal University |
He Y.,East China Sea Environmental Monitoring Center |
Widney S.,Indiana University Bloomington |
And 4 more authors.
Estuarine, Coastal and Shelf Science | Year: 2016
We measured sediment organic carbon and nitrogen accumulation and rates of denitrification enzyme activity and greenhouse gas (CO2, CH4, N2O) production from slurries of sediments of a mudflat that formed in 2002, a young (8-year-old) natural Spartina alterniflora salt marsh that developed on part of the mudflat, and four mature (>200 years old) salt marshes in southeastern Georgia to examine microbial processes related to carbon (C) and nitrogen (N) cycling during succession from mudflat to mature marsh. Soil organic C and N and C: N ratio (0-30 cm) increased across the chronosequence from mudflat (791 ± 35 g C/m2, 125 ± 17 g N/m2) to young marsh (2520 ± 131 g C/m2, 190 ± 10 g N/m2) to mature marshes (5827 ± 250 g C/m2, 372 ± 20 g N/m2). After 8 years of colonization by S. alterniflora, sediment organic carbon increased 3.2 times, and nitrogen increased 1.5 times relative to the mudflat. The high rate of organic C and N accumulation based on time series measurements (188 g C/m2/yr, 7.8 g N/m2/yr) and feldspar marker layers (359 g C/m2/yr, 26.2 g N/m2/yr) was attributed to high accretion (cm/yr) in this low elevation (0.18 m NAVD88) emerging marsh. Carbon dioxide production increased with increasing sediment organic C from mudflat to mature marshes. Un-amended denitrification enzyme activity, measured in slurry incubations, ranged from an average of 0.020 ± 0.005 μg g-1 hr-1 in the mature marshes to 0.094 ± 0.03 μg g-1 hr-1 in the young marsh. We also measured denitrification potential in slurry incubations amended with C (glucose), N (nitrate), and C + N to assess the potential for substrate limitations. Denitrification potential in the mudflat did not show strong nutrient limitation. In the young marsh, denitrification potential was C-limited, and in the mature marsh, it was co-limited by C and N. In July samples, CO2 production showed a statistically significant increase with age from the mudflat to the mature marshes. However, in both months, CO2 production efficiency (expressed on a per g C basis) was significantly higher in the mudflat sediment slurries than in the young marsh and mature marsh samples. Spartina colonization of mudflats and the subsequent accumulation of organic matter are key to enriching sediment organic C and N pools that control microbial heterotrophy, particularly denitrification and CO2 production, which play important roles in marsh C and N cycling. © 2016 Elsevier Ltd.