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1.
Marion GS Dunbar RB Mucciarone DA Kremer JN Lansing JS Arthawiguna A 《Marine pollution bulletin》2005,50(9):931-944
This study introduces a new method of tracing the history of nutrient loading in coastal oceans via delta(15)N analysis of organic nitrogen preserved in the skeleton of the massive Porites coral. Four coral cores were collected in Bali, Indonesia, from reefs exposed to high levels of fertilizers in agricultural run-off, from lagoonal corals impacted by sewage, and from a reef located 30 km offshore. Skeletal delta(15)N in the agriculturally exposed coral declined from 10.7+/-0.4 per thousand in 1970-1971, when synthetic fertilizers (-0.8 per thousand+/-0.2 per thousand) were introduced to Bali, to a depleted "anthropogenic" baseline of 3.5 per thousand+/-0.4% in the mid-1990s. delta(15)N values were negatively correlated with rainfall, suggesting that marine delta(15)N lowers during flood-bourn influxes of waste fertilizers. Reef cores exposed to untreated sewage in terrestrial discharge were enriched (7.8 and 7.3+/-0.4 per thousand), while the offshore core reflected background oceanic signals (6.2+/-0.4 per thousand). delta(15)N, N concentration, and C:N systematics indicate that the N isotopic composition of skeletal organic matter was generally well preserved over 30 years. We suggest that skeletal organic delta(15)N can serve as a recorder of past nitrogen sources. In Bali, this tracer suggests that the intensification of Western style agricultural practices since 1970 are contributing to the degradation of coastal coral reefs. 相似文献
2.
Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ("sewage plume mapping") technique, which measures the delta(15)N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades. 相似文献
3.
The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and delta(15)N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in delta(15)N among sites, but with two exceptions had delta(15)N above 10 per thousand, reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (delta(15)N= approximately 14-17 per thousand and 8-12 per thousand, respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries. 相似文献
4.
Estuarine fish health assessment: evidence of wastewater impacts based on nitrogen isotopes and histopathology 总被引：2，自引：1，他引：1
Sewage effluent is a powerful agent of ecological change in estuaries. While the effects of sewage pollution on water quality are usually well documented, biological responses of exposed organisms are not. We quantified health impacts in the form of pathological tissue changes across multiple organs in estuarine fish exposed to elevated levels of treated wastewater. Structural pathologies were compared in wild populations of four fish species from two subtropical estuaries on the east coast of Australia that differ substantially in the amount of direct wastewater loadings. Uptake of sewage-derived nitrogen by fish was traced with stable nitrogen isotopes. Pathologies were common in the liver, spleen, gill, kidney and muscle tissues, and included granulomas, melanomacrophage aggregates, and multiple deformities of the gill epithelia. Tissue deformities were more frequent in fish exposed directly to wastewater discharges. Mullet (Valamugil georgii) were most affected, with only a single specimen free of pathologies in the sewage-impacted estuary. Similarly, in those fish that had structural abnormalities, more deformities were generally found in individuals from sites receiving sewage. These spatial contrasts in impaired fish health correspond to significantly enriched delta15N values in fish muscle as a consequence of fish assimilating sewage-N. Overall, the pattern of lower health and enriched delta15N values in fish from sewage-impacted areas suggests that organism health is lowered by sewage inputs to estuaries. Measurements of organism health are required to understand the effects of sewage on estuarine ecosystems, and histopathology of fishes is a powerful tool to achieve this. 相似文献
5.
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
6.
The main aim of this study was to estimate the influence of the seasonal variations of the Danube River particulate organic matter (POM) inputs on the Black Sea surface seawater POM and upper layer of sediments along the Romanian coast. Ratios of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) stable isotopes allowed differentiating river and marine organic matter sources. Danube River POM presented significantly lower average values of delta(13)C (-27.52+/-0.88 per thousand) and delta(15)N (4.88+/-1.45 per thousand) than seawater POM (delta(13)C=-24.70+/-2.37 per thousand and delta(15)N=6.75+/-1.96 per thousand), whereas surface sediment presented average values similar to seawater POM (delta(13)C=-24.02+/-2.39 per thousand and delta(15)N=7.29+/-2.16 per thousand). Stable isotope values showed that the Danube River influence on marine ecosystems decreased from the North to the South of the Romanian coast. Strong seasonal variations of C and N isotopic signatures were observed in all compartments studied with generally higher values in spring when the river was flooding. 相似文献
7.
Stable carbon and nitrogen isotope signatures indicate recovery of marine biota from sewage pollution at Moa Point,New Zealand 总被引：4，自引：0，他引：4
Rogers KM 《Marine pollution bulletin》2003,46(7):821-827
Stable carbon and nitrogen isotopes have been used to assess sewage contamination of a sewage outfall, discharging milli-screened effluent into Moa Point Bay, New Zealand, and monitor the recovery of flora and fauna after the outfall's closure. An initial study characterising the extent of the discharge and the effects on seaweed (Ulva lactuca L.), blue mussels (Mytilus galloprovincialis) and limpets (Cellana denticulata) from the area, showed effects of the sewage discharge on flora and fauna were localised within in the bay. The immediate area surrounding the discharge area was found to contain limited biodiversity, with an abundance of Ulva lactuca, a bright green lettuce-like seaweed, typically found in areas with high nutrient input, limpets and small blue mussels. The nitrogen isotopic signature (delta15N) is shown to be a good tracer of sewage pollution in seaweed and associated grazers (i.e. limpets) as a result of the increased contribution of urea and ammonia to seawater nitrogen derived from the effluent. The carbon isotopic signature (delta13C) is suggested as a more appropriate sewage tracer for mussels, which filter feed the effluent's particulate organic matter from the water. Lower carbon:nitrogen ratios were found in Ulva lactuca sampled from around the outfall region compared to uncontaminated control sites. However carbon:nitrogen ratios do not vary significantly amongst shellfish species.After closure, monitoring continued for 9 months and showed that the carbon and nitrogen isotopic signatures of algae (Ulva lactuca L.) returned to similar control site levels within 3 months. Limpet and blue mussels (Cellana denticulata and Mytilus galloprovincialis) showed slower recovery times than the Ulva lactuca, with detectable levels of the sewage-derived carbon and nitrogen remaining in the animal's tissue for up to 9 months. 相似文献
8.
Bioerosion by Cliona delitrix and Cliona lampa was assessed at 43 sites along the Florida Reef Tract, USA, in the summer of 2001. Sponge abundances were estimated using rapid visual assessment. Tissue samples of sponges were taken for analysis of delta15N. Comparison samples were taken from Belize. Annual trends in sponge abundance were estimated from archived videos covering the period from 1996 to 2001. Sites with the greatest boring sponge size and cover were in the Backcountry and Lower Keys, where total nitrogen, ammonium, and delta15N levels were highest. The sites with the largest relative increase of C. delitrix and C. lampa over the 5 year period were in the Upper Keys, where the greatest relative decline in stony coral cover has occurred. Florida sponge delta15N values were 5.2(+/-0.1)%, suggesting the influence of human waste; in comparison, offshore Belize samples were 2.1(+/-0.1)%. These results suggest sewage contamination of the Florida Reef Tract, shifting the carbonate balance from construction to destruction. 相似文献
9.
delta15N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems
In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;> or =1.0 micro M) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and delta15N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical delta15N values were found in seagrass leaves of several species at each site. The correlations between delta15N and nutrient concentrations and between delta15N and molar ratios of nutrients suggested that nutrient availability did not affect the delta15N value of seagrass leaves by altering the physiological condition of the plants. Increases in delta15N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that delta15N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water. 相似文献
10.
进入湖泊中不同氮源氮稳定同位素值(δ15N)的差异和生物对氮稳定同位素的记忆作用,可以反映流域人类活动输入的污染物对生态系统的影响程度.本文调查了太湖4个湖湾(梅梁湾、贡湖湾、竺山湾和东太湖)中铜锈环棱螺(Bel-lamya aeruginosa)的δ15N值,结果表明环棱螺δ15N值的变幅为6.9‰～18.1‰,平均值为11.2‰,不同湖湾中环棱螺δ15N值差异极显著,从高到低依次为梅梁湾(17.7‰)、贡湖湾(13.2‰)、东太湖(10.2‰)和竺山湾(7.8‰).分析认为,梅梁湾和贡湖湾接纳较多的人类活动产生的污染物,其周边城市如无锡、常州等地的污水处理效率有待提高;竺山湾水体氮素主要来自于农业面源污染,需降低农田化肥的使用量. 相似文献
11.
《Marine pollution bulletin》2013,72(1-2):152-158
Assessments of sewage pollution routinely employ stable nitrogen isotope analysis (δ15N) in biota, but multiple taxa are rarely used. This single species focus leads to underreporting of whether derived spatial N patterns are consistent. Here we test the question of ‘reproducibility’, incorporating ‘taxonomic replication’ in the measurement of δ15N gradients in algae, seagrasses, crabs and fish with distance from a sewage outfall on the Adelaide coast (southern Australia). Isotopic sewage signals were equally strong in all taxa and declined at the same rate. This congruence amongst taxa has not been reported previously. It implies that sewage-N propagates to fish via a tight spatial coupling between production and consumption processes, resulting from limited animal movement that closely preserves the spatial pollution imprint. In situations such as this where consumers mirror pollution signals of primary producers, analyses of higher trophic levels will capture a broader ambit of ecological effects. 相似文献
12.
Curt Forsberg 《Marine pollution bulletin》1994,29(6-12):409-413
The large-scale flux of nitrogen and phosphorus in modern society is coupled to the exponentially growing world population. During the last three decades there has been a several-fold growth in use of nitrogen (N) and phosphorus (P), for example, for agriculture production, in chemical products such as in detergents, and as food additives. Feeding a growing population means increased human nutrient excretion.
The mobility of N differs from that of P. For the easily mobile nitrate ion, river exports are positively correlated to the size of local human populations. P on the other hand is fixed in different systems, at least temporarily. Modern agro-ecosystems accumulate about 60% of the annual input of P. The Stockholm region representing an urban ecosystem served by dephosphatation in sewage, accumulated about 80% of imported P during 1990. With increasing accumulation there is an apparent risk for increasing non-point source pollution.
In some shallow recipient lakes the sediments have been saturated with P. Even after the reduction of external loading these lakes are exporting more P than they are importing. Lakes normally are traps for P.
In order to prevent damage to natural resources and to stop the large-scale flux of nutrients from land to water, the world population growth rate must be decreased and a number of measures taken: agricultural structures must be changed including new concepts for the use of fertilizers; new municipal sewage treatment processes must be developed permitting high-degree recycling of nutrients; unnecessary use of nutrients must be stopped, for example, in detergents and by reducing nutrient additives in food and drinks. Cola drinks, for example, contain 180 mg P l−1, a concentration about 350 times higher than that of the effluent (0.5 mg P l−1) from modern sewage treatment plants operating with dephosphatation. Financial resources and effort are required to stop large-scale eutrophication of marine waters. 相似文献
13.
In an effort to identify biomonitors for contamination of Antarctic marine benthos by sewage, this study determines whether the US Antarctic Program’s McMurdo Station produces a benthic sewage footprint and whether resident megafauna are assimilating sewage-derived material. We identified strong C and N isotopic gradients in benthic sediment as a function of downstream distance from McMurdo Station’s point-source sewage addition. Sediment C and N isotope ratios approached marine background levels at the sampling end-point 612 m downcurrent. Based on isotope abundances in their tissues, at least some sewage C and N were assimilated by the sedentary, suspension feeding soft coral Alcyonium antarcticum, ascidian Cnemidocarpa verrucosa and bivalve Laternula elliptica. However, as inferred by tissue-sediment differences in downstream isotope trends, such assimilation was not in proportion to sewage exposure and input, therefore implying non-generalist feeding behavior by these species. In contrast, the motile, generalist feeding sea urchin Sterechinus neumayeri, sea star Odontaster validus and ribbon worm Parborlasia corrugatus showed isotopic evidence of sewage C and N assimilation roughly in proportion to sewage input. We recommend these generalist feeders for further use as biomonitors at this site now that sewage treatment has been implemented. As these species are circumpolar in distribution, they may also prove useful elsewhere in the Antarctic. 相似文献
14.
Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves and epiphytes) were harvested from different locations throughout the bay during the touristic summer and rainy seasons. The results from the nitrogen analysis revealed that sewage and harbor outflow promote higher nitrogen levels, enrichment of 15N in the tissues, and a higher seasonal variability in sea grass and epiphytes. In mussel tissues, the δ15N was also influenced by sewage and harbor outflow, whereas δ13C was influenced by terrestrial inputs. These results suggest that natural and anthropogenic nutrient inputs have a temporary and localized influence and affect the sensitivity of natural isotopic ratios to changes in hydrologic conditions, especially to rain and tourism. 相似文献
15.
At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds (“black shales”) were found to have significantly lower δ15N values (lower15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in particular have °15N values that are significantly lower than those previously found in the marine sediment record and most contemporary marine nitrogen pools. In contrast, black, organic-carbon-rich beds at a third site (DSDP Site 603) contain predominantly terrestrial organic matter and have C- and N-isotopic compositions similar to organic matter of modern terrestrial origin.The recurring15N depletion in the marine-derived Cretaceous sequences prove that the nitrogen they contain is the end result of an episodic and atypical biogeochemistry. Existing isotopic and other data indicate that the low15N relative abundance is the consequence of pelagic rather than post-depositional processes. Reduced ocean circulation, increased denitrification, and, hence, reduced euphotic zone nitrate availability may have led to Cretaceous phytoplankton assemblages that were periodically dominated by N2-fixing blue-green algae, a possible source of this sediment15N-depletion. Lack of parallel isotopic shifts in Cretaceous terrestrially-derived nitrogen (Site 603) argues that the above change in nitrogen cycling during this period did not extend beyond the marine environment. 相似文献
16.
为深入了解湿地周丛生物碳(C)、氮(N)、磷(P)生态化学计量的变化规律及其影响因素,对贵州草海湿地4种不同生境(湖滨带、人工湿地、农田沟渠、污水处理厂)中周丛生物两个生长阶段(生长期和衰老期)的C、N、P生态化学计量学进行了研究.结果表明:水体营养指数依次为污水处理厂(51.55±4.50)>农田沟渠(50.41±4.50)>人工湿地(47.20±6.72)>湖滨带(41.86±6.91),湿地下游水域水质较上游明显改善.总体来看,在不同生境间,周丛生物C、N、P含量随着水体营养浓度的升高而增加,但周丛生物化学计量比呈下降的趋势.同一生境中,生长期周丛生物的C、N、P含量和C∶N都小于衰老期周丛生物,N∶P和C∶P则相反.周丛生物生长期N、P元素为弱稳态型(HN=2.358,HP=2.576),衰老期为稳态型(HN=10.99,HP=5.78),整体来看两个生长阶段周丛生物的N∶P呈稳态型(HN∶P=4.504).根据周丛生物最佳生长速率计量比得出湖滨带处于P限制状态,而人工湿地、污水处理厂和农田沟渠则不受养分限制.相关性分析表明水体营养水平显著影响周丛生物的N、P元素含量及化学计量比,尤其是水体TP和TN浓度.非线性曲面拟合分析表明,周丛生物N∶P和C∶N分别受水体TP和TN浓度的主要影响,而水体TN和TP浓度对周丛生物C∶P的影响同等重要.该研究表明,基于水体TP、TN浓度和周丛生物化学计量比的三维模型可用来评估水体营养水平和周丛生物化学计量之间的关系. 相似文献
17.
Isotopic evidence of subtle nutrient enrichment in mangrove habitats of Golfo Dulce,Costa Rica 
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下载免费PDF全文 Mangroves are of great ecological and socio‐economic importance, yet they are under threat from urban development on the southern Pacific coast of Costa Rica. To test for possible nutrient‐related impacts, we compared water‐column nutrient concentrations, C and N stable isotope values and other environmental variables between mangroves with known sewage loading (three “nutrient loaded” locations) and those without such loading (three “reference” locations). Instantaneous nutrient concentrations were low at all locations, Secchi depth was greater at reference locations, and chlorophyll concentrations were higher at nutrient loaded mangroves. Suspended matter did not vary between reference and nutrient loaded mangroves, and nor did bivalve and algal δ13C and δ15N values. Enrichment of δ15N and δ13C of red mangrove leaves at the nutrient loaded locations is attributed to pulsed inputs of materials that were not detected in the instantaneous nutrient data. We provide evidence of isotopic enrichment at nutrient loaded locations from mangrove material and recommend that adequate waste water treatment be carried out on all anthropogenic discharges into this vulnerable marine system. 相似文献
18.
Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures 总被引：6，自引：0，他引：6
Total organic carbon (TOC), total nitrogen (TN) and their δ(13)C and δ(15)N values were determined for 42 surface sediments from coastal Bohai Bay in order to determine the concentration and identify the source of organic matter. The sampling sites covered both the marine region of coastal Bohai Bay and the major rivers it connects with. More abundant TOC and TN in sediments from rivers than from the marine region reflect the situation that most of the terrestrial organic matter is deposited before it meets the sea. The spatial variation in δ(13)C and δ(15)N signatures implies that the input of organic matter from anthropogenic activities has a more significant influence on its distribution than that from natural processes. Taking the area as a whole, surface sediments in the marine region of coastal Bohai Bay are dominated by marine derived organic carbon, which on average accounts for 62±11% of TOC. 相似文献
19.
Puerto Galera Bay is a coastal lagoon with a variety of marine habitats and high species diversity. It is an area in the Phillippines where the growing influence of human activities is affecting the quality of its marine resources. This study examined the distribution and behaviour of nutrients and the physical hydrography of Puerto Galera Bay and determined how its physico-chemical nature affected the condition of biotic components in the bay. The relative importance of the nitrogen and phosphorus signals were used as indicators to implicate the influence of sewage and run-off into the bay. A nutrient pool accumulated in the bay as a result of low flushing rates. The interaction of hydrodynamic forcing with the biota have implications on the phytoplankton production and coral communities in the area. 相似文献