Most environmental bio-monitoring methods using the species composition of marine faunas define the Ecological Quality Status of soft bottom ecosystems based on the relative proportions of species assigned to a limited number of ecological categories. In this study we analyse the distribution patterns of benthic foraminifera in the Mediterranean as a function of organic carbon gradients on the basis of 15 publications and assign the individual species to five ecological categories. Our categories (of sensitive, indifferent and 3rd, 2nd and 1st order opportunists) are very similar to the ecological categories commonly used for macrofauna, but show some minor differences. In the 15 analysed publications, we considered the numerical data of 493 taxa, of which 199 could be assigned. In all 79 taxa were classified as sensitive, 60 as indifferent, 46 as 3rd order, 12 as 2nd order and 2 as 1st order opportunists. The remaining 294 taxa are all accessory, and will only marginally contribute to biotic indices based on relative species proportions. In this paper we wanted also to explain the methodology we used for these species assignments, paying particular attention to all complications and problems encountered. We think that the species list proposed here will constitute a highly useful tool for foraminiferal bio-monitoring of soft bottoms in the Mediterranean Sea, which can be used in different ecological indices (Foram-AMBI and similar methods). With additional information becoming available in the next few years, it will be possible to expand the list, and, if necessary, to apply some minor corrections. As a next step, we intend to test this species list using several biotic indices, in a number of independent data sets, as soon as these will become available.
The marine environment in the Gulf of Gabes (southern Tunisia) is severely impacted by phosphate industries. Nowadays, three localities, Sfax, Skhira and Gabes produce phosphoric acid along the coasts of this Gulf and generate a large amount of phosphogypsum as a waste product. The Gabes phosphate industry is the major cause of pollution in the Gulf because most of the waste is directly discharged into the sea without preliminary treatment. This study investigates the marine environment in the proximity of the phosphate industries of Gabes and the coastal marine environment on the eastern coast of Djerba, without phosphate industry. This site can be considered as "pristine" and enables a direct comparison between polluted and “clean” adjacent areas.Phosphorous, by sequential extractions (SEDEX), Rock-Eval, C, H, N elemental analysis, and stable carbon isotope composition of sedimentary organic matter, X-ray diffraction (qualitative and quantitative analysis) were measured on sediments. Temperature, pH and dissolved oxygen were measured on the water close to the sea floor of each station to estimate environmental conditions. These analyses are coupled with video surveys of the sea floor. This study reveals clear differentiations in pollution and eutrophication in the investigated areas.
Quantitative and qualitative analyses of cold-water coral (CWC) fragments from two sediment cores obtained from the Melilla Mounds Field (MMF) in the Alboran Sea, western Mediterranean Sea, reveal an alternation of periods dominated by distinct CWC species. The lower parts of the cores are dominated by the CWC species Lophelia pertusa, which is successively replaced in the upper parts by the species Madrepora oculata and Dendrophyllids. The transition in the macrofauna coincides with a characteristic change in the benthic foraminiferal assemblage. Benthic foraminiferal assemblage BFA glacial , in accordance with benthic (Cibicides lobatulus) and planktic (Globigerina bulloides) δ 13 C and δ 18 O values provide evidence for generally high surface productivity, cold and well-ventilated bottom waters lasting from the end of Marine Isotope Stage 3 (33.3 ka BP) reaching a maximum at the transition Alleröd-Younger-Dryas. Together with δ 13 C of the organic carbon and Rock-Eval pyrolysis, benthic foraminiferal assemblage BFA interglacial established since the Early Holocene indicates that the MMF experienced a decrease in bottom-water energy that caused an organic carbon-enrichment in the sediments and also depleted oxygen waters. Compared to the pre-Holocene interval dominated by the planktic foraminifera Neogloboquadrina incompta and the benthic foraminiferal assemblage BFA glacial , the organic carbon deposited during the Holocene in the MMF contains more refractory components in relation to sea-level rise and modern oceanographic configuration. Based on our data, we suggest that L. pertusa has a higher ecological requirement than M. oculata and Dendrophyllids especially with regard to oxygen and nutrient availability.
Tropical marine ecosystems are richly diverse, but are experiencing growing pressure from coastal development and tourism. Assessing the status of coral reef communities along gradients of human pressure is necessary to predict recovery capacity of reefs exposed to acute events such as mass bleaching or storm destruction. Islands in the central Maldives Archipelago, which experience three different management regimes (four for each category: local community, uninhabited, and resort islands), were sampled during the International Union for Conservation of Nature (IUCN)-REGENERATE Cruise in 2015. Assessments were carried out using the FoRAM Index (FI), based on relative abundances of larger foraminiferal shells in reef sediments.Overall, FI values (> 5) indicate that water quality currently should support active accretion by reef-building corals and larger benthic foraminifers. The highest median FI values (5.9) were recorded from sites associated with the uninhabited islands. Slightly, but significantly lower medians were recorded at sites near community and resort islands (FI = 5.3 and 5.1, respectively) that host permanent human settlement, indicating possible local deterioration of water quality by disposal of domestic wastes. Note that the FI was designed to assess suitability of local water quality and not to assess responses to regional to global changes associated with temperature stress or ocean acidification.
Coral reefs are threatened worldwide by a variety of natural and human-induced stressors; anomalous temperatures are presently among the most serious threats by causing extensive coral bleaching. Amphistegina spp. exhibit similar bleaching as corals in the presence of photo-oxidative stress induced by either light or temperature, especially during times of maximum solar irradiance. At 11 islands (34 sampling sites) in the North Ari Atoll in the Maldives, bleaching in Amphistegina was observed a few weeks before the onset of an extensive El Niño-related coral bleaching that was more severe than expected for this region. Assessment using the Amphistegina Bleaching Index (ABI) showed that the proportions of bleached specimens of Amphistegina in April–May 2015 can be explained by photo-inhibitory stress associated with temperatures exceeding 30°C during peak seasonal solar irradiance and water transparency. Importantly, the ABI indicates that environmental conditions are suitable for Amphistegina and other calcifying symbioses at most of the investigated sites, and that either chronic or relatively recent onset of photo-oxidative stress was present at the time of sampling. The observed bleaching in Amphistegina further demonstrates the potential of these unicellular protists to identify stressors in coral reefs; such applications should be considered in future reef-management plans.
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