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1.
Biomonitoring of estuarine pollution is the subject of active research, and benthic foraminifera are an attractive group to use for these purposes due to their ubiquitous presence in saline water and wide diversity. Here, we describe a case study of biomonitoring using benthic foraminifera in the French Mediterranean lagoon, Bages-Sigean lagoon. In this case, the major pollutants of interest are heavy metals in the sediment, particularly contaminated by Cu and Cd derived from industrial and agricultural sources. The foraminiferal assemblages of the Bages-Sigean lagoon are typical of normal paralic environments, but unusually almost completely lack agglutinated forms. The density of benthic foraminifera was shown to be more influenced by the sediment characteristics rather than heavy metal pollution. However, the relative abundance of Quinqueloculina bicostata was shown to increase in the most polluted areas and we propose that this taxon may be used as an indicator of heavy metal pollution.  相似文献   

2.
The eastern Mediterranean is naturally highly oligotrophic, but urbanization along the Levant coast has led to raised organic and nutrient loads. This study tracks living foraminiferal assemblages at two sites near an activated sewage sludge outfall from 11/2003 to 5/2004. Oligotrophic site PL29 shows seasonal variations in O2, chlorophyll a, and organic carbon, and has an abundant, diverse benthic foraminiferal assemblage living at various in-sediment depths. At eutrophic site PL3, ∼16 years of sludge injection favor a depleted assemblage primarily of opportunist foraminifera. This site shows less seasonality, is subjected to organic matter overload, O2-stress, and periodic anoxia, foraminifera are less abundant and diverse, and live at shallower depths. The assemblages at both sites represent a common pool of species, with Ammonia tepida highly dominant. Benthic foraminifera were therefore found to be sensitive to trophic trajectories, respond on sub-seasonal time-scales, and track injection and dispersal of organic loads on the shelf.  相似文献   

3.
A study of foraminiferal assemblages was carried out in 24 sediment samples collected from the Montevideo coastal zone (south-eastern coastal region of South America) to assess the response of the benthic foraminifera to the polluted sediments. The area is affected by different pollutants such as sewage, hydrocarbons and heavy metals derived from different sources. Biological data were analyzed with multivariate techniques of cluster analysis and a principal component analysis (PCA) was performed for abiotic factors. The results allowed the recognition of different species assemblages corresponding to different sub-environments, which reflected the prevalent ecological conditions. The Montevideo Bay, particularly, its inner part showed an extremely poor foraminiferal fauna-including a totally azoic station-and high percentages of abnormal tests, when compared with the adjacent Punta Carretas and Punta Yeguas zones. Mean faunal density showed a strong relationship with organic matter, oxygen and heavy metal concentrations, as well as redox potential and pH values of each sub-environment. Although the adjacent zones presented a moderate pollution degree, it was noticed that a positive effect on the foraminiferal density specially on Ammonia tepida, caused by the sewage pipe located in Punta Carretas, a pure organic contamination. Differences among foraminiferal assemblages seemed to be related to the combined action of the several kinds of pollutants and the natural abiotic variables, like the rapid salinity changes that occurred in this area.  相似文献   

4.
Concentrations of major and trace metals were determined in eight sediment cores collected from the inter-tidal zone of the Medway Estuary, Kent, UK. Metal associations and potential sources have been investigated using principal component analysis. These data provide the first detailed geochemical survey of recent sediments in the Medway Estuary. Metal concentrations in surface sediments lie in the mid to lower range for UK estuarine sediments indicating that the Medway receives low but appreciable contaminant inputs. Vertical metal distributions reveal variable redox zonation across the estuary and historically elevated anthropogenic inputs. Peak concentrations of Cu, Pb and Zn can be traced laterally across the estuary and their positions indicate periods of past erosion and/or non-deposition. However, low rates of sediment accumulation do not allow these sub surface maxima to be used as accurate geochemical marker horizons. The salt marshes and inter-tidal mud flats in the Medway Estuary are experiencing erosion, however the erosion of historically contaminated sediments is unlikely to re-release significant amounts of heavy metals to the estuarine system.  相似文献   

5.
We assess species composition, assemblage structure and distribution of the benthic foraminiferal assemblages from diverse substrates in Moreton Bay, South-East Queensland, Australia. Analysis of 47 surface sediment samples revealed 69 species, three distinct foraminiferal assemblages and six sub-assemblages. The assemblages from the western Bay are characterized by stress tolerant taxa and the lowest diversity, whereas the assemblages from the eastern Bay are characterized by symbiont-bearing taxa and high diversity. We found a correlation between foraminiferal assemblages and substrate conditions that was indicative of strong environmental gradients (substrate type, water quality and salinity), from an urban-impacted assemblage in the westernmost part of the Bay, to a hyposaline, estuarine-influenced assemblage in the western Bay to a nearly normal marine to hypersaline assemblage in the eastern Bay. The FORAM Index was consistent with the changes in water and sediment quality gradient, from the western shoreline to the eastern Bay. Thus the foraminiferal assemblages of Moreton Bay make excellent bio-indicators of environmental changes in a subtropical, estuarine setting in eastern Australia.  相似文献   

6.
《Marine pollution bulletin》2010,60(8-12):268-280
Benthic foraminifera and sediment texture were studied on a total of 37 samples, collected from two brackish-water coastal basins: Fogliano Lake and Lungo Lake (central Italy). The research was performed as a preliminary low-cost survey to highlight the degree of the environmental stress and to recognize a possible anthropogenic disturbance. The sedimentological and foraminiferal data were processed by bivariate and multivariate statistical analysis. Three distinct assemblages, referable to different environments were recognized for the Fogliano Lake: inner, intermediate and outer lagoon. Only the outer lagoon assemblage was found in the Lungo Lake. The distribution of foraminifera in the Fogliano Lake suggests a natural environmental stress probably due to the ecological instability typical of marginal environments, while the absence of the inner and intermediate lagoon assemblages in the Lungo Lake suggests an environmental disturbance possibly related to human activities. An interdisciplinary survey including geochemical analyses is recommended in order to deduce the nature and degree of pollution in the Lungo Lake.  相似文献   

7.
The Natural Park of Do?ana and the Guadalquivir estuary were impacted by the release of 6 million cubic meters of acid waste after the mine-tailing spill in Aznalcóllar (Andalusia, SW, Spain). Here is presented the monitoring of the accidental spill on vertical distribution of heavy metals in the estuarine sediments. The total concentration of six metals (Fe, Mn, Zn, Cd, Pb, Cu), their chemical speciation and the organic carbon concentration were analyzed in sediment vertical profiles. The results obtained determine background levels similar to previously reported in the area. The analysis catalogues the impact of the accident on the estuary as acute and mainly associated with high concentrations of Zn and Cd. The recent enrichment in Zn and Cd and their geochemical association with the more mobile fractions of the sediment determine an environmental risk associated with the acute impact and detected in some of the areas of the estuary.  相似文献   

8.
《Marine pollution bulletin》2010,60(8-12):297-310
The ecological status of an environment should be evaluated by comparison with local “reference conditions”, here defined as the pre-industrial ecological status of the 19th century. This pilot study illustrates how micropalaeontological monitoring, using benthic foraminifera (protists) and associated geochemical parameters preserved in inner Oslofjord (Norway) sediments, characterise local reference conditions. In order to optimise the usefulness of the ecological information held by foraminifera and enable characterisation of temporal changes in environmental quality beyond time intervals covered by biological time-series, the Norwegian governmental macrofauna-based classification system is applied on fossil benthic foraminiferal assemblages. Quantitative comparisons demonstrate deteriorating ecological status in response to increased anthropogenic forcing (eutrophication, micropollutants), including a 73% loss in number of foraminiferal species. Despite reduced pollution during the past decades and, at one site, capping of polluted sediments with clean clay, the reference conditions are far from re-established. Micropalaeontological monitoring requires net sediment accumulation basins and careful considerations of taphonomic processes.  相似文献   

9.
Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites.  相似文献   

10.
Benthic foraminiferal assemblages were investigated from two sites along the axis of the Cassidaigne Canyon (NW Mediterranean Sea). Both areas are contaminated by bauxite red mud enriched in iron, titanium, vanadium and chromium. These elemental enrichments are related to bauxite-derived minerals and various amorphous phases. At the shallowest station located very close to the pipe outlet, the benthic living foraminiferal community is characterised by a very low diversity and by an unusual dominance of Gyroidina umbonata and Bulimina marginata. The mechanical stress related to downslope transport of red mud is a likely source of hydro-sedimentary pollution precluding the settlement of diverse fauna. The living and dead foraminiferal faunas from the deepest site are typical of oligo-mesotrophic conditions prevailing in natural environments. There, bauxite residues have obviously no environmental impact on foraminiferal faunas. The bioavailability of trace metals is likely low as elemental enrichments were not observed in foraminiferal test chemistry.  相似文献   

11.
Geochemical composition (Al, Zn, Pb, Cd, Cu, Ni, Cr and As) and foraminiferal assemblages in surface and core sediments were determined to assess the current situation and the recent environmental transformation of the Suances estuary (southern Bay of Biscay, Spain). Dating of the historical record has been achieved using isotopic analysis (210Pb, 137Cs) and two benchmark events such as the beginning of the mineral exploitation in the Reocín Pb-Zn deposits and the evolution of the chlor-alkali industry (inputs of Hg). Concentrations of Zn, Pb and Cd in both surface and core samples are remarkably higher than background values, reflecting the existence of significant amounts of polluted materials. The dramatic environmental impact of this pollution is clearly recorded by the change of the foraminiferal assemblages that even reach an afaunal stage during recent decades. Application of two different sets of Sediment Quality Guidelines confirm that they exert potential risk to the environment, and therefore if dredged they should need specific management measures.The results provide a reference database to monitor future environmental changes in the Suances estuary, particularly as regards the contaminated sediment storage and the re-colonization by autochtonous meiofauna.  相似文献   

12.
《Marine pollution bulletin》2010,60(8-12):257-267
Living benthic foraminiferal assemblages were studied in surface samples collected from the lagoon of Venice (Italy) in order to investigate the relationship between these sensitive microorganisms and trace element pollution. Geochemical analysis of sediments shows that the lagoon is affected by trace element pollution (Cd, Cu, Ni, Pb, Zn and Hg) with the highest concentrations in its inner part, which corresponds to the Porto Marghera industrial area. The biocenosis are largely dominated by Ammonia tepida, Haynesina germanica and Cribroelphidium oceanensis and, subordinately, by Aubignyna perlucida, Ammonia parkinsoniana and Bolivina striatula. Biotic and abiotic factors were statistically analyzed with multivariate technique of cluster analysis and principal component analysis. The statistical analysis reveals a strong relationship between trace elements (in particular Mn, Pb and Hg) and the occurrence of abnormalities in foraminiferal tests. Remarkably, greater proportions of abnormal specimens are usually found at stations located close to the heaviest polluted industrial zone of Porto Marghera. This paper shows that benthic foraminifera can be used as useful and relatively speedy and inexpensive bio-indicators in monitoring the health quality of the lagoon of Venice. It also provides a basis for future investigations aimed at unraveling the benthic foraminiferal response to human-induced pollution in marine and transitional marine environments.  相似文献   

13.
《Marine pollution bulletin》2009,58(6-12):624-631
The Western Scheldt river and estuary is known to be highly polluted as it receives industrial, agricultural and domestic effluents from one of the most populated and industrialised zones in Europe. Aquatic organisms are exposed to pollutants, specifically metals that are present in different environmental phases, e.g. dissolved, suspended material or sediment phases. The objective of this study was to study the relationship that exists between environmental metal levels, the degree of metal uptake by aquatic organisms with the concomitant biological responses. For this purpose the bivalve mollusk, Mytilus edulis, was selected as bioaccumulation indicator organism. Environmental (water and sediment) and mussel samples were collected during the late winter (March 2000) from sampling sites in the Scheldt estuary. Sites were selected to represent a salinity gradient from the mouth of the estuary to the furthest distribution area of mussels upstream in the system. Together with standard water quality parameters (e.g. salinity, dissolved oxygen, dissolved organic carbon, etc.) concentrations of twelve metals were analysed in the water (dissolved and suspended matter) and sediments. Levels of these metals were also measured in the soft tissue of M. edulis, together with concomitant biomarker responses in resident mussel populations at each site. The biomarkers that were included in this study were condition index, scope for growth, survival in air, cell membrane stability, DNA damage, and metallothioneins. Data were subjected to multivariate statistical analysis. The physico-chemical parameters and metals in the environmental samples clustered the sites to reflect the distribution based on the salinity gradient. Bioaccumulation results revealed increased metal uptake along a pollution gradient with the highest metal bioaccumulation occurring at the upstream most sites and therefore closest to the in the industrial activities. However, the biomarker responses clustered the sites in a manner that reflected the influence of combination of internal exposure (bioaccumulation) and external exposure (physico-chemical conditions). These differences in biomarker responses clearly demonstrated were attributed to abiotic factors other than metal pollution alone e.g. localized short-term increases in increased suspended sediment concentrations and decreased dissolved oxygen concentrations.  相似文献   

14.
The Western Scheldt river and estuary is known to be highly polluted as it receives industrial, agricultural and domestic effluents from one of the most populated and industrialised zones in Europe. Aquatic organisms are exposed to pollutants, specifically metals that are present in different environmental phases, e.g. dissolved, suspended material or sediment phases. The objective of this study was to study the relationship that exists between environmental metal levels, the degree of metal uptake by aquatic organisms with the concomitant biological responses. For this purpose the bivalve mollusk, Mytilus edulis, was selected as bioaccumulation indicator organism. Environmental (water and sediment) and mussel samples were collected during the late winter (March 2000) from sampling sites in the Scheldt estuary. Sites were selected to represent a salinity gradient from the mouth of the estuary to the furthest distribution area of mussels upstream in the system. Together with standard water quality parameters (e.g. salinity, dissolved oxygen, dissolved organic carbon, etc.) concentrations of twelve metals were analysed in the water (dissolved and suspended matter) and sediments. Levels of these metals were also measured in the soft tissue of M. edulis, together with concomitant biomarker responses in resident mussel populations at each site. The biomarkers that were included in this study were condition index, scope for growth, survival in air, cell membrane stability, DNA damage, and metallothioneins. Data were subjected to multivariate statistical analysis. The physico-chemical parameters and metals in the environmental samples clustered the sites to reflect the distribution based on the salinity gradient. Bioaccumulation results revealed increased metal uptake along a pollution gradient with the highest metal bioaccumulation occurring at the upstream most sites and therefore closest to the in the industrial activities. However, the biomarker responses clustered the sites in a manner that reflected the influence of combination of internal exposure (bioaccumulation) and external exposure (physico-chemical conditions). These differences in biomarker responses clearly demonstrated were attributed to abiotic factors other than metal pollution alone e.g. localized short-term increases in increased suspended sediment concentrations and decreased dissolved oxygen concentrations.  相似文献   

15.
The Western Scheldt river and estuary is known to be highly polluted as it receives industrial, agricultural and domestic effluents from one of the most populated and industrialised zones in Europe. Aquatic organisms are exposed to pollutants, specifically metals that are present in different environmental phases, e.g. dissolved, suspended material or sediment phases. The objective of this study was to study the relationship that exists between environmental metal levels, the degree of metal uptake by aquatic organisms with the concomitant biological responses. For this purpose the bivalve mollusk, Mytilus edulis, was selected as bioaccumulation indicator organism. Environmental (water and sediment) and mussel samples were collected during the late winter (March 2000) from sampling sites in the Scheldt estuary. Sites were selected to represent a salinity gradient from the mouth of the estuary to the furthest distribution area of mussels upstream in the system. Together with standard water quality parameters (e.g. salinity, dissolved oxygen, dissolved organic carbon, etc.) concentrations of twelve metals were analysed in the water (dissolved and suspended matter) and sediments. Levels of these metals were also measured in the soft tissue of M. edulis, together with concomitant biomarker responses in resident mussel populations at each site. The biomarkers that were included in this study were condition index, scope for growth, survival in air, cell membrane stability, DNA damage, and metallothioneins. Data were subjected to multivariate statistical analysis. The physico-chemical parameters and metals in the environmental samples clustered the sites to reflect the distribution based on the salinity gradient. Bioaccumulation results revealed increased metal uptake along a pollution gradient with the highest metal bioaccumulation occurring at the upstream most sites and therefore closest to the in the industrial activities. However, the biomarker responses clustered the sites in a manner that reflected the influence of combination of internal exposure (bioaccumulation) and external exposure (physico-chemical conditions). These differences in biomarker responses clearly demonstrated were attributed to abiotic factors other than metal pollution alone e.g. localized short-term increases in increased suspended sediment concentrations and decreased dissolved oxygen concentrations.  相似文献   

16.
From the first finding in 1970s, the findings of foraminiferal fossil assemblages in inland basins have been reported from time to time, especially in recent years. The debates on the depositional environment of foraminiferal fossils have become the hot spot of researches again in China. Based on the researches of trace element geochemistry and electron scanning microscope of shells of Quaternary foraminiferal fossils from the Xiaodukou section in the inland Nihewan basin, the original 87Sr/86Sr and other geochemical information of shells were believed to be preserved well and could be used to rebuild the geochemistry of contemporary waters where foraminifera deposited, although there existed some effects of burial diagenesis on the geochemistry of shells to a certain extent. The 87Sr/86Sr ratios of well-preserved Xiaodukou foraminiferal shells were measured, giving a range of 0.711190±25–0.712018±14, apparently higher than the value of contemporary seawater (0.709087–0.709147) and similar to that of the Sanggan River, proving that it represented the value of the ancient lacustrine water. The hyperbolic mixing models of 87Sr/86Sr-palaeosalinity and 87Sr/86Sr-Sr/Ca indicated that the contemporary waters where Xiaodukou foraminifera inhabited was an inland lake and there was no seawater input to the depositional environment.  相似文献   

17.
《Marine pollution bulletin》2013,77(1-2):333-348
The Bay of Bakar is one of the most heavily polluted bays at the Eastern Adriatic. Three major industrial companies potentially endanger the bay. The concentration of major, minor and trace elements in surface sediments from thirteen stations was discussed in relation to the sediment type and foraminiferal assemblages. The distribution of major elements in the bay is influenced by geological nature of surroundings. Heavy metal distribution depends on pollution sources and on amount of mud fraction: fine-grained sediments are enriched by them in comparison with coarse-grained ones. Different sediment quality criteria complicate the pollution assessment in the bay. Heavy metal concentrations generally fall into allowed depositional values for marine environments; only area in front of the coke plant and the City of Bakar harbor is heavily polluted. Stress-tolerant foraminiferal species dominate at stations with higher concentrations of heavy metals and coarse-grained sediments consist of larger number of epifaunal taxa.  相似文献   

18.
《Marine pollution bulletin》2017,114(1):384-396
We investigated benthic foraminiferal assemblages in contaminated sediments in a subarctic harbor of Northern Norway to assess their utility as indicators of anthropogenic impacts. Sediments in the harbor are repositories for POPs and heavy metals supplied through discharges from industry and shipping activities. Sediment contaminant concentrations are at moderate to poor ecological quality status (EcoQS) levels. The EcoQS based on benthic foraminiferal diversity reflects a similar trend to the EcoQS based on contaminant concentrations. Foraminiferal density and diversity is low throughout the harbor with distinct assemblages reflecting influence of physical disturbances or chemical stressors. Assemblages impacted by physical disturbance are dominated by L. lobatula and E. excavatum, while assemblages impacted by chemical stressors are dominated by opportunistic species S. fusiformis, S. biformis, B. spathulata and E. excavatum. The foraminiferal assemblage from an un-impacted nearby fjord consists mainly of agglutinated taxa. These assemblages provides a valuable baseline of the ecological impacts of industrialization in northern coastal communities.  相似文献   

19.
In this paper, we analyze two short cores collected in the Tinto estuary (SW Spain), and describe the palaeoenvironmental evolution of this area during the last two millennia, along with the influence of historical mining activities and recent industrial pollution on sediments and microfauna (foraminifera and ostracoda). Although there were no significant changes in the distribution of microorganisms, a first pollution period (0-150 AD) was recorded in high sediment pollution by Cu in the shallow palaeochannels of the middle estuary. During this period and the following 1700 years, tolerant pioneer species of both foraminifera and ostracoda were found predominantly in the inner, protected areas of the estuary, while the bottom sediments were subjected to high hydrodynamic gradients, and consequently showed lower density and diversity of organisms. In the last 150 years, acid mine drainage processes, introduction of a new mining period, and the polluted inputs derived from two industrial processes resulted in increased heavy metal contamination of the bottom sediments, and corresponding extirpation of ostracodes and restriction of foraminifers to the inner zones of the estuary.  相似文献   

20.
A total of 92,934 fish larvae representing 19 families were sampled monthly from the Sangga Kecil estuary (Matang Mangrove Forest Reserve) and adjacent coastal waters from May 2002 to October 2003. Larval fish assemblages were numerically dominated by Gobiidae (50.1%) and Engraulidae (38.4%). Canonical Correspondence Analysis (CCA) revealed that the larval fish assemblages, including their ontogenetic stages, differed between the mangrove estuary and adjacent offshore waters, and that salinity, turbidity and zooplankton food are the major environmental factors structuring the larval fish assemblages. Estuarine preflexion gobiid larvae were ubiquitous in the coastal and estuarine waters. Larval stages of euryhaline species that were spawned in offshore waters, such as Engraulidae and Clupeidae, were largely advected into mangrove areas at the postflexion stages. Larvae of other euryhaline fishes (Sciaenidae, Blenniidae and Cynoglossidae) that may have been spawned inside the estuary were, however, exported to offshore waters. Given that the collective number of juvenile and adult fish families in the Matang estuary was 53, while the number of larval families was only 17, the former is quite disconnected from the existing larval fish population in the estuary.  相似文献   

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