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We used growth rates of juvenile winter flounderPseudopleuronectes americanus to assess anthropogenic influence on habitat quality at three sites in Narragansett Bay, Rhode Island. The upper bay site,
Gaspee Point, had the highest population density and concentration of total nitrogen; human inputs decreased down bay. Growth
rates of individually marked fish were measured in three 15-d experiments from June 8 to July 6, 1998 in 1-m2 cages placed at upper, middle, and lower bay sites. Water temperature, salinity, dissolved oxygen (DO), and benthic food
were also measured. Stable isotopes of nitrogen and carbon were measured in experimental fish as possible indicators of nutrient
enrichment and to identify organic carbon sources. Growth rates were 0.22–0.60 mm d−1, with the highest average at the mid-bay site. Growth was initially fastest at Gaspee Point, but dropped off as DO concentrations
fell. Step-wise multiple regression indicated that location (upper, middle, or lower bay) explained most of the variability
in fish growth (40%). Coefficients of other significant variables indicated that fish grew faster at lower salinities, smaller
sizes, and with decreased time that DO was below 2.3 mg l−1. Benthic prey varied among sites and there was significantly less food and fewer species at Gaspee Point.Polydora cornuta was a favored food at all sites and was found in over half the stomachs. Values of δ15N in fish and sediments did not reflect differences in total nitrogen concentrations recorded near the sites. We suggest that
anthropogenic influences, such as nutrients and sewage, affected habitat quality by reducing DO, which lowered fish growth
rates. 相似文献
2.
Various waterborne anthropogenic contaminants disrupt the endocrine systems of wildlife and humans, targeting reproductive pathways, among others. Very little is known, however, regarding the occurrence of endocrine disruptive activity in South African freshwater ecosystems, and coastal ecosystems have not been studied in this regard. In a first attempt to investigate endocrine disruptive activity in South African coastal waters, surface water samples collected from harbours, river mouths and estuaries in three metropolitan municipalities, eThekwini (which includes Durban), Nelson Mandela (specifically Port Elizabeth Harbour) and City of Cape Town, were screened for (anti) oestrogenicity and (anti)androgenicity using recombinant yeast bioassays. Moreover, levels of the female hormone 17β-(o)estradiol (E2) were determined in all samples, as well as a selection of hydrocarbons in the eThekwini samples. A high proportion of samples collected from eThekwini were oestrogenic, whereas none from Port Elizabeth Harbour and only a single river mouth sampled in the City of Cape Town were oestrogenic. E2 was detected in all the samples tested, but at higher concentrations at the eThekwini and City of Cape Town localities than Port Elizabeth Harbour. In addition, the recombinant yeast assays revealed that anti-androgenicity was widespread, being detected in the majority of samples screened apart from those representing Port Elizabeth Harbour. Conversely, no anti-oestrogenic or androgenic activity was detected. Anti-androgenicity did not associate with hydrocarbon loads, providing evidence that other anti-androgens were responsible for the observed activity. The present data suggest potential reproductive disruption in marine and estuarine fauna inhabiting the eThekwini and City of Cape Town regions. 相似文献
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Stable nitrogen isotope ratios were used to study the incorporation of anthropogenically-derived nitrogen into the food webs of salt marsh systems along a contamination gradient in Narragansett Bay. Nitrogen isotope ratios (delta(15)N) were measured in six estuarine species collected from three marshes along this gradient, monthly from June to October between 1997 and 1999. A significant decrease in delta(15)N was found with distance along the estuary for four of the six species. Significant differences were found among monthly isotope ratios for some species. Nitrogen isotope ratios in sea lettuce (Ulva lactuca) increased during the summer season with highest delta(15)N values measured during September and October. This trend was most pronounced at the station receiving the highest nutrient inputs. Elevated delta(15)N values at this station appeared to correlate with seawater ammonia/nitrate concentration ratios. The temporal variations in delta(15)N suggest that care should be taken in species selection and the design of sampling schemes of studies using delta(15)N for monitoring anthropogenic nutrients in aquatic systems. Sampling programs designed to determine long-term trends should consider species that do not show rapid fluctuations in isotope ratios. The mud snail, Nassarius obsoletus, responded this way in the present study. Studies designed to measure short-term changes should include species such as U. lactuca, which rapidly respond to isotope changes. The results from this study also help to establish a baseline for nitrogen isotope values in Narragansett Bay. This information can be used to monitor future trends in nitrogen inputs to this estuary. 相似文献
4.
R J Pruell B K Taplin D G McGovern R McKinney S B Norton 《Marine environmental research》2000,49(1):19-36
A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passaic River, NJ, USA, for 70 days. These polychaetes were then fed to the American lobster, Homarus americanus, for up to 112 days. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), 2,4,6,8-tetrachlorodibenzothiophene (TCDT), polychlorinated biphenyls (PCBs), and several chlorinated pesticides were accumulated by polychaetes following exposure to the contaminated sediment. Some of these contaminants were also accumulated by lobsters which were exposed to the contaminated sediment and/or fed contaminated polychaetes. Only the lesser chlorinated PCDDs and PCDFs (mostly tetra- and pentachlorinated congeners) and 2,4,6,8-TCDT were detected in the polychaetes and lobster. Significant alterations were noted in the PCB patterns found in both species, particularly the lobster. The non-ortho-substituted PCBs (such as congeners 77 and 126) became enriched in the PCB mixtures of the polychaetes and especially the lobsters relative to the sediment, probably because these congeners were not metabolized. These congeners and the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents of the PCB mixtures were enriched by a factor of about six in the lobsters relative to the sediment. Elimination of PCB congeners containing vicinal hydrogens in the meta-para region is consistent with cytochrome P450IIB-type metabolism. Based on the concentration trends for some PCB congeners and chlorinated pesticide ratios measured in the lobsters during this experiment, it appears that this metabolic system is inducible in the American lobster. 相似文献
5.
Gonzalez Francisco R. Raval Simit Taplin Ros Timms Wendy Hitch Michael 《Natural Resources Research》2019,28(2):393-408
Natural Resources Research - The impact that climate change may play in the future sustainability of mining projects has become increasingly important for the mining industry and its stakeholders.... 相似文献
6.
The paper incorporates the recent dynamic geomorphic changes observed in the coastal tracts around the Little Gulf of Kachchh, Gujarat. Some of the changes observed within last 30 years include silting up, migration and joining of different creeks, reorientation of tidal current ridges and regression of sea. These changes appear to be related to tectonically activated lineaments passing through the Little Gulf. 相似文献
7.
Narrowing research and policy, while challenging, is especially important in climate change adaptation work (CCA) due to the high uncertainties involved in planning for climate change. This article aims to seek stakeholders’ opinions regarding how research and policy development can be bridged within the Cambodian water resources and agriculture sectors. The study used institutional ethnography methods with informants from government organizations, local academia, and development partners (DPs). This article identifies a number of challenges, and barriers for narrowing research–policy development gaps, including: limited effectiveness of governmental policies and planning; lack of relevant information required to promote evidence-based planning and policy development; and communication barriers. Evidence-based planning is valued by government officials most when there is actual and effective implementation of policies and plans. In practice, this often implies that governmental policies and plans need be scoped and scaled down to meet the available budget, and thus be achievable. In the long term, it also means building the capacity for policy-relevant research on climate change adaptation within Cambodia. Engaging policy stakeholders in research process for co-producing adaptation knowledge, and introducing knowledge intermediaries are suggested by informants as means to narrowing gaps between research and policy development. The presence of the Cambodia's Prime Minister in research–policy dialogues is recommended as important for attracting the attention of high-level policy makers.
Policy relevance
As a least developed and highly climate-vulnerable country, Cambodia has received climate change funding to implement a number of climate adaptation initiatives. Cambodia is likely to receive more climate change finance in the future. This article aims to assist evidence-based planning, in particular, through policy-relevant research on CCA, so that resources for adaptation in Cambodia are used effectively and efficiently. This research also directly benefits the sustainable development of the country. 相似文献
8.
In this paper, we look at the relationship between the development of domestic and overseas markets for Australian renewable energy. It is argued that encouraging the promotion of Australian renewable energy technology in overseas markets could be a practical strategy for developing the Australian renewable energy industry. Also, it is reasoned, Australian foreign aid and trade organisations could play an important role in assisting the Australian renewable energy industry via overseas market research, technology transfer, and human resource and institutional development programs. We suggest that further research and development cooperation between Australian renewable energy companies and research institutes would be beneficial, especially in exploring potential overseas markets. We also recommend that joint ventures between renewable energy industry partners in Australia and developing countries be used to promote growth in Australian renewable energy exports and, ultimately, in developing Australia's renewable energy industries. 相似文献
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