Coastal water quality and trophic status are subject to intensive environmental stress induced by human activities and climate change. Quarterly cruises were conducted to identify environmental characteristics in Daya Bay in 2013. Water quality is spatially and temporally dynamic in the bay. Cluster analysis (CA) groups 12 monitoring stations into two clusters. Cluster I consists of stations (S1, S2, S4-S7, S9, and S12) located in the central, eastern, and southern parts of the bay, representing less polluted regions. Cluster II includes stations (S3, S8, S10, and S11) located in the western and northern parts of the bay, indicating the highly polluted regions receiving a high amount of wastewater and freshwater discharge. Principal component analysis (PCA) identified that water quality experience seasonal change (summer, winter, and spring-autumn seasons) because of two monsoons in the study area. Eutrophication in the bay is graded as high by Assessment of Estuarine Trophic Status (ASSETS). (C) 2016 Elsevier Ltd. All rights reserved.
The anaerobic-anoxic-aerobic (A(2)O) process is a highly efficient sewage treatment method, which uses complex bacterial communities. However, the effect of copper on this process and the bacterial communities involved remains unknown. In this study, a systematic investigation of the effect of persistent exposure of copper in the A(2)O wastewater treatment system was performed. An A(2)O device was designed to examine the effect of copper on the removal efficiency and microbial community compositions of activated sludge that was continuously treated with 10, 20, and 40 mg L-1 copper, respectively. Surprisingly, a decrease in chemical oxygen demand (COD) and ammonia nitrogen (NH4-N) removal efficiency was observed, and the toxicity of high copper concentration was significantly greater at 7d than at 1d. Proteobacteria, Bacteroidetes, Acidobacteria, Chlorobi, and Nitrospirae were the dominant bacterial taxa in the A(2)O system, and significant changes in microbial community were observed during the exposure period. Most of the dominant bacterial groups were easily susceptible to copper toxicity and diversely changed at different copper concentrations. However, not all the bacterial taxa were inhibited by copper treatment. At high copper concentration, many bacterial species were stimulated and their abundance increased. Cluster analysis and principal coordinate analysis (PCoA) based on operational taxonomic units (OTUs) revealed clear differences in the bacterial communities among the samples. These findings indicated that copper severely affected the performance and key microbial populations in the A(2)O system as well as disturbed the stability of the bacterial communities in the system, thus decreasing the removal efficiency. (C) 2016 Elsevier Ltd. All rights reserved.
Using high-resolution in situ data from gliders, satellite data of sea level anomaly and geostrophic currents, we presented the detailed structure of an anticyclonic eddy during spring 2015 in the northern South China Sea. The impact depth of the anticyclonic eddy reached about 1000 m and had a maximum temperature anomaly of about 3 degrees C at similar to 120 m and maximum salinity anomaly of more than 0.3 psu in the mixed layer. The maximum geostrophic velocities perpendicular to the glider path were about 0.3 m s(-1) at 100 m. The estimated radius was about 72 km and the translation velocity was about 5.2 cm s(-1). The rotational speed of the eddy was estimated to be 0.35 m s(-1). The high temperature and large salinity of the anticyclonic eddy indicated it did not originate from the South China Sea locally. The analysis of water mass indicated the character of the eddy water was similar to Kuroshio water, and the time evolution of the sea level anomaly and surface geostrophic velocity anomaly further validated that it originated from the Kuroshio intrusion as a loop current to the southwest of Taiwan.
Multicellular magnetotactic prokaryotes (MMPs) are a peculiar group of magnetotactic bacteria, each comprising approximately 10-100 cells of the same phylotype. Two morphotypes of MMP have been identified, including several species of globally distributed spherical mulberry-like MMPs (s-MMPs), and two species of ellipsoidal pineapple-like MMPs (e-MMPs) from China (Qingdao and Rongcheng cities). We recently collected e-MMPs from Mediterranean Sea sediments (Six-Fours-les-Plages) and Drummond Island, in the South China Sea. Phylogenetic analysis revealed that the MMPs from Six-Fours-les-Plages and the previously reported e-MMP CandidatusMagnetananas rongchenensis have 98.5% sequence identity and are the same species, while the MMPs from Drummond Island appear to be a novel species, having >7.1% sequence divergence from the most closely related e-MMP, CandidatusMagnetananas tsingtaoensis. Identification of the novel species expands the distribution of e-MMPs to Tropical Zone. Comparison of nine physical and chemical parameters revealed that sand grain size and the content of inorganic nitrogen (nitrate, ammonium and nitrite) in the sediments from Rongcheng City and Six-Fours-les-Plages were similar, and lower than found for sediments from the other two sampling sites. The results of the study reveal broad diversity and wide distribution of e-MMPs.
Microwave-infrared, Tropical Rainfall Measuring Mission Microwave Imager and Advanced Microwave Scanning Radiometer - Earth observing system, and WindSat sea surface temperatures are validated in coastal waters of the northern South China Sea using in situ measurements from three anchored buoys from 2010-2013. Validation of satellite sea surface temperatures shows that biases +/- standard deviations of Microwave-infrared, Tropical Rainfall Measuring Mission Microwave Imager and Advanced Microwave Scanning Radiometer - Earth observing system, and WindSat daytime and nighttime sea surface temperatures against Maoming buoy sea surface temperatures are 0.18 +/- 0.74, 0.60 +/- 0.57, 0.76 +/- 0.61, and 0.22 +/- 0.74 degrees C, respectively, and against Shantou buoy sea surface temperatures are 0.02 +/- 0.58, 0.05 +/- 0.53, 0.04 +/- 0.69, and -0.05 +/- 0.71 degrees C, respectively. Because the Shanwei buoy is very close to the coast, the bias of satellite sea surface temperatures against the Shanwei buoy sea surface temperatures is very large, especially in the winter. The mean biases of satellite sea surface temperatures in coastal waters, except for very close to the coast, are roughly equivalent to previous results in the northern South China Sea. The accuracies of satellite sea surface temperatures in coastal waters of the northern South China Sea depend not only on season, wind speed, wind direction, and region, but also on the satellite product. Accuracy and applicability of satellite-derived sea surface temperature also has the potential to further improve, especially in near-coastal areas.
In order to evaluate the effects of pH reduction in seawater as a result of increasing levels of atmospheric CO2, laboratory-scale experiments simulating the scenarios of ocean acidification (OA) and CO2 leakages of carbon capture and storage (CCS) were performed using the model organism Moina mongolica Daday. The LpH50s calculated in cladoceran toxicity tests showed that M. mongolica exhibited intermediate sensitivity to OA, which varied among species and with ontogeny, when compared with different phyla or classes of marine biota. Survival, reproduction and fecundity of parthenogenetic females were evaluated after 21-day exposures. Results showed that increased acidity significantly reduced the rate of reproduction of M. mongolica resulting in a decreased intrinsic rate of natural increase (r(m)) across the gradients of pH reduction. The analysis of macromolecule contents in neonates suggested that nutritional status in progeny from all broods were significantly reduced as seawater pH decreased, with increasing magnitude in latter broods, except the contents of protein from two former broods and lipids from the first brood. Our findings clearly showed that for this ecologically and economically important fish species, the negative effects of pH reduction on both "quantity" and "quality" of progeny may have far-reaching implications, providing direct evidence that OA could influence the energetic transfer of marine food web and ecosystem functions in acidified oceans in the future. (C) 2016 Elsevier Ltd. All rights reserved.