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31.
《Limnologica》2015
To establish the influence of phytoplankton blooms on the dynamics and sources of dissolved organic carbon (DOC) in Lake Taihu, the concentrations and stable carbon isotope values (δ13C) of DOC and particulate organic carbon (POC) were analyzed, along with environmental factors, including water temperature, chlorophyll a (Chl a) concentration, phytoplankton community and total bacterial abundance, from March to August 2013 at five sites in Lake Taihu. Significant differences were observed in the DOC concentrations and δ13CDOC values at the sampling sites. On average, the proportion of DOC in the total organic carbon (TOC) pool ranged from 30% ± 10% to 81% ± 7%. POC was positively associated with both Chl a concentration and cyanobacteria biomass, suggesting that cyanobacteria blooms contribute to the POC pool in Lake Taihu. Depleted 13C in DOC relative to POC was observed in August, indicating that DOC was partially derived from POC in August. However, Chl a explained only 40% of the variation in DOC in the entirety of Lake Taihu, and at two sites far from the estuary, the contribution of allochthonous carbon was less than 50% in August. These results suggested a greater influence of allochthonous sources on the DOC pool. Moreover, the biodegradability of DOC was further determined by the total dissolved carbohydrates to DOC ratio (TCHO/DOC), specific UV absorbance (SUVA254), and the concentrations of bioavailable DOC (BDOC). On average, 17% of the variation in DOC was attributable to the BDOC pool, and the BDOC concentration correlated positively with Chl a, cyanobacteria biomass, and total bacterial abundance, suggesting that cyanobacteria–derived DOC is biodegradable and is preferentially utilized by bacteria. 相似文献
32.
The in vitro solubilization and bioaccumulation of mercury and other trace metals by the intestinal fluid of the sea cucumber, Sclerodactyla briareus, was investigated. Sediments were incubated with intestinal fluid and the intestinal fluid was analyzed for the in vitro experiments. Experiments examined both procedural effects of in vitro solubilization and bioaccumulation of trace metals by the sea cucumber. Both solubilization and bioaccumulation were compared among the different metals. This comparison revealed that monomethylmercury (MMHg) solubilization and bioaccumulation is greater than HgI; Cd solubilization is higher than MMHg and HgI; and Cu and Pb solubilization is similar to MMHg and slightly higher than HgI. Solubilization and bioaccumulation was found to be very low, except for Cd, which had high relative solubilization but low bioaccumulation. It was concluded that while solubilization could be the rate-limiting step for certain metals, other factors, such as depuration and membrane transport, may influence overall bioaccumulation of the other metals. 相似文献
33.
Bioavailability of dissolved organic phosphorus compounds to typical harmful dinoflagellate Prorocentrum donghaiense Lu 总被引：1，自引：0，他引：1
Bangqin Huang Linjian Ou Huasheng Hong Haiwei Luo Dazhi Wang 《Marine pollution bulletin》2005,51(8-12):838
The bioavailability of dissolved organic phosphorus (DOP) compounds to harmful alga Prorocentrum donghaiense Lu and its alkaline phosphatase activity (APA) were studied. Results showed that P. donghaiense could utilize the test DOP compounds such as glucose-6-phosphate (G-6-P), adenosine triphosphate (ATP) and ribonucleic acid (RNA) to sustain its growth. Nutrition between the test DOP compounds and orthophosphate was comparable. P. donghaiense could utilize intracellular phosphorus to sustain growth under depletion of dissolved phosphorus. Variation of APA in different test DOP compounds was addressed; the controlling mechanism of APA in different DOP media was discussed. 相似文献
34.
Bioavailable copper and manganese in soils from Iceland and their relationship with scrapie occurrence in sheep 总被引：1，自引：0，他引：1
The bioavailability of trace metals can be directly linked with many common animal and human diseases. It is easier to correlate regional geochemical trends with disease distribution in the developing world because local populations and animals live from the land. In the western world, humans tend to live from the global food market whereas animals graze on the land. Recent biochemical studies have shown that the prion protein needs copper to keep its structure. If copper is not available, the prion protein can take up manganese and unfold. Preliminary results for trace metals in soil samples from scrapie-affected areas in Iceland show that bioavailable manganese manganese (easily reducible and exchangeable Mn) is very high whereas soluble copper and free copper are very low. 相似文献
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36.
Dredging related metal bioaccumulation in oysters 总被引：1，自引：0，他引：1
Bivalves are regularly used as biomonitors of contaminants in coastal and estuarine waters. We used oysters to assess short term changes in metal availability caused by the resuspension of contaminated sediments. Sydney Rock Oysters, Saccostrea glomerata, were deployed at multiple sites in Port Kembla Harbour and two reference estuaries for 11 weeks before dredging and for two equivalent periods during dredging. Saccostrea experienced large increases in accumulation of zinc, copper and tin during dredging in the Port relative to oysters deployed in reference estuaries. Lead and tin were found to be permanently elevated within Port Kembla. We present a clear and un-confounded demonstration of the potential for dredging activities to cause large scale increases in water column contamination. Our results also demonstrate the usefulness of external reference locations in overcoming temporal confounding in bioaccumulation studies. 相似文献
37.
Environmental geochemistry of the Gulf Creek copper mine area, north-eastern New South Wales, Australia 总被引：13，自引：3，他引：10
Past mining and smelting of sulphide ore (pyrite-chalcopyrite-sphalerite) at the abandoned Gulf Creek mine has resulted in
a stream highly contaminated by acid mine drainage (pH: 2.2–3.4), as well as degradation of local soil and vegetation. Physical
dispersion of secondary metal-bearing minerals from abandoned ore and waste dumps into Gulf Creek and adsorption and coprecipitation
of dissolved metals and metalloids in the stream bed cause elevated Ag, As, Cd, Cu, Fe, Pb and Zn values in stream sediments.
The bioavailability of individual heavy metals to freshwater organisms changes downstream, however, selective bioaccumulation
processes in algae reject readily bioavailable Zn and concentrate less bioavailable Cu. Polluted soils in the vicinity of
the mine and smelter sites are subject to continuing soil erosion and either support no vegetation, or a depauperate flora
with certain species showing bioaccumulation of metals and resistance to high metal contents. Rehabilitation of disturbed
areas should involve covering and sealing sulphidic mine waste or removal of ore and waste dumps, installation of a physical
and chemical plant or construction of a wetland environment (plus anoxic lime drains), and import of topsoil and planting
of local, metal-tolerant plant species.
Received: 17 March 1998 / Accepted: 6 October 1998 相似文献
38.
海藻多糖植物空心胶囊体内生物利用度与生物等效性研究 总被引：1，自引：0，他引：1
采用三交叉、自身对照的方法,研究了3种药用空心胶囊的体内相对利用度,并评估了其生物等效性,以检验本实验室研发的海藻多糖空心胶囊替代动物明胶空心胶囊的可行性。实验选择了12名志愿者,以布洛芬为模型药物,采用高效液相色谱法(HPLC)检测志愿者体内的血药浓度变化,用DAS2.0计算主要药动学参数,并评价其生物利用度及生物等效性。结果显示,海藻多糖植物空心胶囊替代动物明胶空心胶囊并不影响人体内药物吸收;海藻多糖植物空心胶囊布洛芬胶囊剂与日本Qualicaps布洛芬胶囊剂(相对生物利用度94.9%)、明胶布洛芬胶囊剂(相对生物利用度97.5%)均具有生物等效性。 相似文献
39.
Seasonal variations and bioavailability of inorganic phosphorus in soils of Yeyahu Wetland in Beijing, China 总被引：4，自引：0，他引：4
Phosphorus (P) in soils has an important influence on the development and productivity of wetland. The objective of this study was to investigate the distribution, bioavailability and seasonal variations of inorganic phosphorus (IP) in soils of Yeyahu Wetland. The results showed that the concentration of Ca-bound P (Ca-P) remained the main occurrence in all IP fractions despite the season, at the same time the Al-bound P (Al-P) was always the lowest IP fraction despite the season. Al-P and Fe-bound P (Fe-P) concentration were all reached the highest value in May and the lowest in November, which was opposite to the occluded P (Oc-P) fraction. The notable higher Oc-P concentration in November observed in this study was probably due to the decomposition of plants and the subsequently releasing of oxides to soils. Ca-P didn't change much with season variations. Exchangeable P (Ex-P) and Oc-P were all positively correlated with soil moisture content and organic matter content, but Al-P was negatively correlated with these two soil properties. As a stable form, Ca-P was not associated with soil properties. Al-P, Fe-P and Ca-P might contribute to the storage of P in studied wetland with the principle component analysis results. The concentration rank order of the bio-available P in soils was generally as follows: Olsen-P > Algal available P (AAP) > Water soluble P (WSP) > Readily desorbed P (RDP). Olsen-P was positively correlated with Ex-P and Oc-P, and it was thought to be a more suitable indicator for bio-available P in soils. 相似文献
40.