[en] Eutrophication is widely recognised as one of the major menaces to coastal environments, particularly enclosed bays and lagoons. Although there is a general understanding of the consequences of eutrophication in these systems, there is a lack of sufficient knowledge concerning biotic feedbacks that influence eutrophication patterns and the resistance capacity of coastal environments. In this paper, the isotope ratios of main producers and consumers of a Mediterranean lagoon were examined in order to elucidate the fate of anthropogenic inputs from the main watercourse flowing into the lagoon. The results of the study of stable isotope data in the Mar Menor lagoon reflected that the whole benthic community plays an important role as a natural 'filter' that removes excess nutrients from the water column and stores them in the sediments, thereby enhancing lagoon resistance to eutrophication.

[en] Tidal flat ecosystem simulators are used to clarify the effects of stranded fuel oil on tidal flat ecosystems. Results show that oil spills increase the periphyton on sediment by decreasing the predation stress caused by deposit feeders. About a month after an oil spill, the total population density of the macrobenthos recovered. The oxidation-reduction potential in the surface sediment drops to a negative value after the oil spill, and the anaerobic condition throughout the sediment seems to be responsible for the decrease in the population density of the macrobenthos. The infiltration volume of seawater into the oil-stranded sediment decreases to a third of that without the oil spill. The recovery of infiltration volume after about a month coincides with the recovery of the population density of the macrobenthos. This result suggests that the macrobenthic population is highly dependent on the infiltration of seawater. (author)

[en] The rocky meso-littoral is an area characterized by the presence of an important amount of organisms that tolerate constant immersions. In this study the faunistic structure of an area of these features located on Concha Bay, Parque Nacional Natural Tayrona, Magadalena, Colombia, was evaluated. Samples from the west and east zones on this bay were taken. We found 19.912 specimens on the east and 11.198 on the west zones belonging to the phyla: Cnidaria, Arthopoda, Equinoderma and Mollusca, being the last one the most frequent. However the diversity index Shannon-Wiener indicates that the area studied has intermediate diversity values

[en] We examined two types of potential habitat for macrozoobenthos: 1 morphological units; 2 types of flow as a complex of hydraulic characteristics of habitat. Both types of habitats were analyzed by their physical attributes and macroinvertebrate communities. Froude (Fr) and Reynolds (Re) number turned out to be suitable as a descriptor of the average hydraulic habitat conditions. The structure of the communities involved abundance, food types, substrate, saprobic and current preferences. From directly measured variables the most significant effect had the flow velocity. (author)

[en] Two sites located in the sublittoral fine-sand macrobenthic community of the Ares-Betanzos Ria were sampled over four years (December 1992-November 1996) in the wake of the Aegean Sea oil spill. This sampling revealed that the petroleum had affected the structure and abundance of this community, as well as the number of taxa present. In this context, the results of the biotic index and the biotic coefficient were insufficient; however, study of the synthetic parameters, particularly through multivariate analysis, showed that the community went through three successive and distinct phases over time. A short period of high mortality in some species, especially amphipods, was followed by a period of low abundance that lasted until the spring of 1995. A period of recovery began in the second half of 1995 and continued through to the end of 1996, when the survey ended. The community showed a gradual evolution back towards the conditions observed immediately after the spill, when abundance of the more resistant species was still high. Despite this similarity, the last period exhibits a new structure, clearly separate from the two previous periods. This study provides information about the short-term effects of the Aegean Sea oil spill on the fine sand bottoms of the sites surveyed in the Ares-Betanzos Ria. This information could also serve as a baseline for identifying the effects of a more recent accident, the Prestige oil spill, in which similar communities in other Galician rias were polluted in 2002-2003. (author)

[en] The sinking of the tanker Eurobulker in Southern Evoikos gulf (Aegean Sea, Greece) in September 2000 resulted in a spill of 700 tons of crude oil. The environmental impact of the spill was studied by the National Centre for Marine Research. The hydrocarbon concentrations in water, sediment and coastal benthic organisms were measured and the response of the benthic communities to the disturbance caused by the oil spill was studied along the direction to the coast and over three sampling seasons. The most severe and direct effects were evidenced on the muddy benthic communities of the accident site and the stations in the close vicinity sampled shortly after the spill. The effects included reduction of the species richness and community diversity, but the communities reached full recovery 8 months later. The impact of the spill was more indirect and delayed in the coastal stations, where as the hydrocarbon measurements indicated, the pollutants were transported later and induced their effects on the benthic communities 6 months after the accident. (author)

[en] We examined two types of potential habitat for macrozoobenthos: 1 morphological units; 2 types of flow as a complex of hydraulic characteristics of habitat. Both types of habitats were analyzed by their physical attributes and macroinvertebrate communities. Froude (Fr) and Reynolds (Re) number turned out to be suitable as a descriptor of the average hydraulic habitat conditions. The structure of the communities involved abundance, food types, substrate, saprobic and current preferences. From directly measured variables the most significant effect had the flow velocity. (author)

[en] Benthic animal densities, biomass and production were studied in a weir basin and the upstream adjacent riffle area in a regulated west Norwegian river in 1988 and 1989. In 1989 heavy precipitation and a mild winter climate caused surplus production of hydroelectric power. Consequently large amounts of stored water had to be released as overflow at the dam. The change in flow regime resulted in reduced biomass and faunal changes. Biomass was high during 1988 and the first months of 1989. Corresponding to the flow increase in June 1989 the biomass in the weir basin was reduced from 7.1 to 2.2 g dw m^-2 and from 8.0 to 0.8 g dw m^-2 at the two studied transects. The mean biomass in the autumn period was 270 and 800% higher at the two transects in 1988 compared to 1989. A great part of the biomass reduction was caused by reduced densities of the chironomids Stictochironomus pictulus and Chironomus melanotus. An increase in the biomass was recorded for rheophilic insect larvae, such as the stoneflies Leuctra fusca and Capnia pygmaea. On the other hand lentic caddis larvae such as Apatania spp. and Oxyethira spp. were reduced. Mean benthic animal production of the weir basin was reduced in 1989. In a riffle upstream of the weir basin the production was reduced in the same period. The faunal change is explained by an altered physical environment and destruction of lentic habitats. (Author)

[en] The experimental Kislogubskaija Tidal power (KTP) was constructed in Russia near Murmansk in 1963-68. It began to produce electricity in 1974 and the water exchange between the bay and the open sea declined drastically. As a result, the upper 15 m layer of water was less saline, and the deeper 20 m of water contained hydrogen sulphide. The normal marine ecosystem was destroyed completely. Beginning in 1984 the water exchange with the open sea increased up to 30-40 %, which corresponds to the project regime. Marine ecosystems began slowly to be restored. In 1992-93 we did not find considerable differences in species composition.. The KTP case study helps to expose the most strong impact of TP on marine ecosystems, which probably could be avoided on big TP stations. (authors)

[en] Stable isotopes in carbonate often provide a record of changes in the seawater environment of formation. At least some marine bryozoan skeletons precipitate carbonate in isotopic equilibrium with sea water. Skeletons from throughout New Zealand range from -2 to 3 per thousand ¹⁸) (ppt, PDB), and from -5 to 3 per thousand ¹³C (ppt, PBD). Values of ¹⁸O, in particular, show a good correlation to water temperature. There are unusual 'bryozoan meadows' on the Otago mid-shelf (eastern South Island, New Zealand). Colonies of six major species are large (up to 35 cm high) and interweave to provide a substantial habitat for animals requiring either hard substrate or shelter. It is important in studies of benthic ecology, fisheries, carbonate sedimentology, and marine biodiversity to know the age of these colonies, but growth rate and age structure of bryozoans generally, and those of New Zealand species in particular, are not known. A muli-disciplinary study of this bryozoan skeletal carbonate is on-going at the University of Otago