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Sources and preservation of sedimentary organic matter in the Southern Bohai Sea and the Yellow Sea: Evidence from lipid biomarkers
2014
Lin, Tian | Wang, Lifang | Chen, Yingjun | Tian, Chongguo | Pan, Xiaohui | Tang, Jianhui | Li, Jun
The region of Southern Bohai Sea (SBS) and Yellow Sea (YS) represents one of the best examples of large river-dominated ocean margins. The transport and accumulation of sediments played a primary role in distribution of the lipids in the region and could lead to a preferential accumulation of these more refractory land-based lipids. The spatial distribution of total organic carbon (TOC) matched with the lipid distributions over the shelf, and high TOC presented in the central YS, but TOC burial fluxes decreased from 110ton/km2/yr of SBS to 25–32ton/km2/yr of YS. Good correlations were observed between terrestrial n-alkanes and TOC in the sediments of SBS and northern YS, but they were poor for southern YS, meanwhile higher ratios of nC27+nC29+nC31/nC15+nC17+nC19 (12±6) were observed in SBS, and lower in YS (2.2±1.0), suggesting the Yellow River discharge was an important source of terrestrial organic matter to the shelf.
显示更多 [+] 显示较少 [-]Copper phytoremediation by a salt marsh plant (Phragmites australis) enhanced by autochthonous bioaugmentation
2014
Oliveira, T. | Mucha, A.P. | Reis, I. | Rodrigues, P. | Gomes, C.R. | Almeida, C.M.R.
Here we evaluated whether the potential of Phragmites australis to phytoremediate Cu contaminated sediments could be enhanced by bioaugmentation with an autochthonous microorganism consortium (AMC) that is resistant to Cu.Saltmarsh plants with sediment attached to their roots were collected, placed in vessels and kept in greenhouses, under tidal simulation. Sediments were contaminated with Cu and the AMC was added to half of the vessels.After two months, plants accumulated significant amounts of Cu (2–10 times more) in all tissues although in higher amounts (7–10 times more) in belowground structures. AMC addition increased Cu bioavailability (5–10%) in sediments leading to a decrease in belowground structures biomass. However, bioaugmentation increased Cu translocation, with higher amounts (2 times more) of Cu in the plant stems, without significant visual toxicity signs.Therefore, autochthonous bioaugmentation can increase Cu phytoextraction potential of P. australis, which can be a valuable strategy for the recovery and management of moderately impacted estuaries.
显示更多 [+] 显示较少 [-]Community change and evidence for variable warm-water temperature adaptation of corals in Northern Male Atoll, Maldives
2014
McClanahan, T.R. | Muthiga, N.A.
This study provides a descriptive analysis of the North Male, Maldives seven years after the 1998 bleaching disturbance to determine the state of the coral community composition, the recruitment community, evidence for recovery, and adaptation to thermal stress. Overall, hard coral cover recovered at a rate commonly reported in the literature but with high spatial variability and shifts in taxonomic composition. Massive Porites, Pavona, Synarea, and Goniopora were unusually common in both the recruit and adult communities. Coral recruitment was low and some coral taxa, namely Tubipora, Seriatopora, and Stylophora, were rarer than expected. A study of the bleaching response to a thermal anomaly in 2005 indicated that some taxa, including Leptoria, Platygyra, Favites, Fungia, Hydnophora, and Galaxea astreata, bleached as predicted while others, including Acropora, Pocillopora, branching Porites, Montipora, Stylophora, and Alveopora, bleached less than predicted. This indicates variable-adaptation potentials among the taxa and considerable potential for ecological reorganization of the coral community.
显示更多 [+] 显示较少 [-]Identification of the toxic constituents of sediments in a Brazilian subtropical estuary
2014
Poleza, Fernanda | Souza, Rafael C. | Resgalla, Charrid
Phase 1 of the TIE method was applied to samples of elutriates from sediments of the Itajaí-Açu estuary and adjacent coastal region in southern Brazil. Embryo-larval toxicity assays were used with the sea urchin Arbacia lixula in samples of raw elutriate, and treated with Ulva fasciata, EDTA and sodium thiosulfate. Inside the estuary, ammonia was responsible for more than 40% of the toxicity in both the dredged and undredged regions. A toxicity gradient was observed, between the estuary and the coastal region, with an increase in the importance of metals for the latter. Temporally, there is strong evidence of the influence of dredging and disposal of sediments in the contamination of the coastal dumping site. The results indicating that this area presents limitations in its saturation capacity. Chemical analysis indicated the metal Cu is probably responsible for the toxicity of the sediments observed, without the interference of ammonia.
显示更多 [+] 显示较少 [-]A continuous, real-time water quality monitoring system for the coral reef ecosystems of Nanwan Bay, Southern Taiwan
2014
Tew, Kwee Siong | Leu, Ming-Yih | Wang, Jih-Terng | Zhang, Jiaming | Chen, Chung-Chi | Meng, Pei-Jie
The coral reef ecosystems of Nanwan Bay, Southern Taiwan are undergoing degradation due to anthropogenic impacts, and as such have resulted in a decline in coral cover. As a first step in preventing the continual degradation of these coral reef environments, it is important to understand how changes in water quality affect these ecosystems on a fine-tuned timescale. To this end, a real-time water quality monitoring system was implemented in Nanwan Bay in 2010. We found that natural events, such as cold water intrusion due to upwelling, tended to elicit temporal shifts in coral spawning between 2010 and 2011. In addition, Degree Heating Weeks (DHWs), a commonly utilized predictor of coral bleaching, were 0.92 and 0.59 in summer 2010 and 2011, respectively. Though this quantity of DHW was below the presumed stress-inducing value for these reefs, a rise in DHWs in the future may stress the resident corals.
显示更多 [+] 显示较少 [-]Physiological disturbance of the Manila clam, Ruditapes philippinarum, by altered environmental conditions in a tidal flat on the west coast of Korea
2014
Baek, Min Jeong | Lee, Young-Jae | Choi, Kwang-Sik | Lee, Won-Chan | Park, Hyun Je | Kwak, Jung Hyun | Kang, Chang-Keun
To examine the influence of habitat alteration by tideflat reclamation on the physiological ecology of Ruditapes philippinarum, seasonal variations in its condition, gross biochemical composition, and reproductive cycle were compared for a yearly cycle between a reclaimed flat (Gomsohang, GS) and a natural flat (Hajun, HJ) in Gomso Bay, Korea. Concentrations of chlorophyll a and seston (as well as its energy value as food available to the clam) were consistently higher at HJ than at GS. Condition, dry tissue weight, and energy reserves (proteins and carbohydrates) of the clams were much higher at HJ than at GS during spring–summer, when fast growth and gametogenic development occur. Furthermore, their spring gametogenic development and spawning were advanced at HJ compared with GS. Our results suggest that the Manila clam encounters nutritionally stressful environmental conditions in altered habitats after tideflat reclamation that lead to lowered nutrient accumulation and a changing reproductive cycle.
显示更多 [+] 显示较少 [-]Spatial and temporal characterizations of water quality in Kuwait Bay
2014
Al-Mutairi, N. | Abahussain, A. | El-Battay, A.
The spatial and temporal patterns of water quality in Kuwait Bay have been investigated using data from six stations between 2009 and 2011. The results showed that most of water quality parameters such as phosphorus (PO4), nitrate (NO3), dissolved oxygen (DO), and Total Suspended Solids (TSS) fluctuated over time and space. Based on Water Quality Index (WQI) data, six stations were significantly clustered into two main classes using cluster analysis, one group located in western side of the Bay, and other in eastern side. Three principal components are responsible for water quality variations in the Bay. The first component included DO and pH. The second included PO4, TSS and NO3, and the last component contained seawater temperature and turbidity. The spatial and temporal patterns of water quality in Kuwait Bay are mainly controlled by seasonal variations and discharges from point sources of pollution along Kuwait Bay’s coast as well as from Shatt Al-Arab River.
显示更多 [+] 显示较少 [-]Isolation of 12 microsatellite markers following a pyrosequencing procedure and cross-priming in two invasive cryptic species, Alexandrium catenella (group IV) and A. tamarense (group III) (Dinophyceae)
2014
Laporte, Martin | Shao, Zhaojun | Berrebi, Patrick | Laabir, Mohamed | Abadie, Eric | Faivre, Nicolas | Rieuvilleneuve, Fabien | Masseret, Estelle
Alexandrium catenella (group IV) and Alexandrium tamarense (group III) (Dinophyceae) are two cryptic invasive phytoplankton species belonging to the A. tamarense species complex. Their worldwide spread is favored by the human activities, transportation and climate change. In order to describe their diversity in the Mediterranean Sea and understand their settlements and maintenances in this area, new microsatellite markers were developed based on Thau lagoon (France) samples of A. catenella and A. tamarense strains. In this study twelve new microsatellite markers are proposed. Five of these microsatellite markers show amplifications on A. tamarense and ten on A. catenella. Three of these 12 microsatellite markers allowed amplifications on both cryptic species. Finally, the haplotypic diversity ranged from 0.000 to 0.791 and 0.000 to 0.942 for A. catenella and A. tamarense respectively.
显示更多 [+] 显示较少 [-]Trace element concentrations in barramundi (Lates calcarifer) collected along the coast of Vietnam
2014
Tu, Nguyen Phuc Cam | Ha, Nguyen Ngoc | Haruta, Shinsuke | Takeuchi, Ichirō
We determined concentrations of 23 trace elements (TEs), and stable carbon and nitrogen isotope (δ13C and δ15N) signatures in barramundi (Lates calcarifer) specimens collected along the coast of Vietnam in the Northern (NCZ), Central (CCZ) and Southern (SCZ) zones in the period 2007–2010. A combination of δ13C and δ15N signatures provided insight into ontogenetic shifts in barramundi foraging choices. There were clear zone-dependent differences in Mn, As, Sr and Tl concentrations; levels of Tl were highest in the NCZ, As in the CCZ, and Mn and Sr in the SCZ. Lowest concentrations of Rb occurred in the NCZ, Bi was lowest in the CCZ, and Cd and Cs were lowest in the SCZ. δ15N values significantly increased with increasing Zn, Se, Sn and Cs. Concentrations of TEs in barramundi from Vietnam were below worldwide guidelines for human consumption.
显示更多 [+] 显示较少 [-]The application of histo-cytopathological biomarkers in the mud crab Scylla serrata (Forskal) to assess heavy metal toxicity in Pulicat Lake, Chennai
2014
Arockia Vasanthi, Lourduraj | Muruganandam, Azhagu | Revathi, Peranandam | Baskar, Balakrishnan | Jayapriyan, Kodhilmozhian | Baburajendran, Ramaswamy | Munuswamy, Natesan
The concentrations of heavy metals and their associated structural deformities in the gills, muscles and hepatopancreas of Scylla serrata from Pulicat Lake were determined and compared with crabs live along Kovalam coast. The concentrations of metals were high in the hepatopancreas and gills of crab from Pulicat Lake, whereas, low in crab from the Kovalam coast. Data were visualized using a principal component analysis (PCA). Significant differences were found for all variables at the plot scale; however, the overall variation was relatively low for muscle tissues in both stations. The structural deformities observed in the gills, hepatopancreas and muscle was due to metal toxicity, and the degree of damage was correlated with the elevated metal concentration. The results showed significant metal accumulation and histo-cytological lesions in the crabs from Pulicat Lake. The results suggest that these biomarkers are useful for assessing the impact of metal pollution in the coastal environments.
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