In order to test the relationship between the occurrence of marine debris and the distance from urban areas, nine beaches in the metropolitan area of Salvador, Bahia, Brazil and the adjacent northern coast were studied. Marine debris were collected, sorted in several categories and weighed. It was observed that plastics were numerically the most abundant component of the collected debris. As expected, the beaches closest to Salvador presented the largest density of debris, with the exception of the Porto da Barra beach, which has an efficient public cleaning system and does not have any vegetation, making it difficult toaccumulate solid waste. Linear regression analyses showed significant relationships between the distance from the urban center (Salvador) and the number of marine debris per m2, the total number of debris per beach (abundance), and the diversity of debris types (richness). The results showed that proximity to urban regions was a key factor in the marine debris distribution along the coast.

A primitive-equation model has been used to investigate the meteorologically-driven circulation of the Bay of Algeciras. It is shown that the mean circulation of Atlantic Water (AW) is characterized by an anticyclonic cell, while Mediterranean Water (MW) follows a preferred cyclonic pathway. Meteorological forcing distorts substantially the AW mean circulation pattern, and only modulates that of the MW. Winds drive a vertical circulation cell in the Atlantic layer consistent with Ekman dynamics, whereas the horizontal circulation pattern is markedly dependent on the swift Atlantic jet entering the Mediterranean and changes from clearly anticyclonic to cyclonic as the jet separates or approaches the strait’s northern shoreline. This occurs through atmospheric pressure-driven acceleration/deceleration of the jet, in agreement with internal hydraulics theory predictions. It is also found that the renewal of AW is largely modulated by tides, with meteorological forcing playing a secondary role. The opposite applies to the renewal of MW.

Future impacts from climate change and human activities may increase the likelihood of invasions of native marine species into existing habitats as a result of range shifts. To provide an understanding of the invasion of a native seagrass species (Syringodiumisoetifolium) into a tropical multi-species meadow, detailed field assessments were conducted over a six year period. After establishing in a discrete patch, the extent and standing crop of S.isoetifolium increased 800 and 7000 fold, respectively, between 1988 and 2003 (∼300–260,000 m2 and<1kgDW to 7596±555kgDW). The expansion of S.isoetifolium was confined to subtidal areas and appears primarily from clonal growth. The observed expansion of this species into a new locality was found to be clearly influenced by cumulative impacts and chronic small-scale physical disturbances. This study has immediate relevance to managing impacts which influence the spread of invasive species.

Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard “simulation” flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25°C in low-light was 47days, extending to 267days in the dark at 25°C and 315days in the dark at 31°C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.

The present study aimed to evaluate heavy metal concentrations of Arsenic (As), Copper (Cu), Nickel (Ni), Lead (Pb) and Zinc (Zn), their spatial distribution, enrichment factor index (EF), the pollution load index (PLI) and potential ecological risk (PER) in two different seasons of the year (winter and summer) in surface sediments along southeast coast of the Caspian Sea. The results indicated that there were significant differences between concentrations of As, Ni and Pb in two different seasons. Considering PER, sediments from southeast Caspian coast had low ecological risk. According to PLI, sediment from the southeast coast had no pollution. Risk assessment showed that As threshold concentrations to occasionally be exceeded in the study area.

Review is devoted to the analysis of a radioecological situation in the North-western Black Sea and concerns the levels of contamination of the components of an ecosystem by the main artificial radioactive isotopes (90Sr, 137Cs, 239,240Pu). The long-term accumulation trends of these radionuclides were analyzed in components of the Black Sea ecosystem after the Chernobyl nuclear power plant accident. Zones that have an increased ability to accumulate these radioisotopes were revealed. The assessment of irradiation dose rates formed by 90Sr, 137Cs and 239,240Pu in Black Sea hydrobionts was obtained. The strategy for biodiversity conservation and sustainable management of natural resources should include monitoring of the radioecological state of the marine ecosystems, and the formation of a complex of biogeochemical criteria for assessment of an ecological situation in the sea. This approach is important for marine protected areas, since it allows the formation of a basis for scientific and practical function.

This study describes the changes in hydrology, zooplankton communities and abundance in the Senegal River Estuary (SRE) before and after the breaching of the sandbar in October 2003. Samples were taken in 2003 at 3 stations located upstream (DI), in mid estuary (HY) and downstream (RM), and in 2005 at the same stations (RM becoming Old River Mouth: ORM), plus the new river mouth (NRM) resulting from the morphological evolution of the SRE.The study showed marked seasonal variations that affected the structure and distribution of zooplankton as well as major changes caused by the sandbar opening:–increased marine influence throughout the whole SRE,–changes in the horizontal gradients,–arrival of euryhaline species and increase in meroplankton, in particular decapod larvae,–transformation of the ORM area into a slackwater area with limited exchanges and the highest zooplankton numbers during high waters.

Recently compiled databases facilitated estimation of basin-wide benthic organic biomass and turnover in the Strait of Georgia, an inland sea off western Canada. Basin-wide organic biomass was estimated at 43.1×106kgC and production was 54.6×106kgCyr−1, resulting in organic biomass turnover (P/B) of 1.27×yr−1. Organic biomass and production for sub-regions were predictable from modified organic flux (r2>0.9). P/B declined significantly with increasing modified organic flux, suggesting greater biomass storage in high flux sediments. Biomass and production were highest, and P/B lowest near the Fraser River. Annual basin-wide benthic production was 60% of previously estimated oxidized organic flux to substrates, which agrees with proportional measurements from a recent, localized study.Deviations from expected patterns related to organic enrichment and other stressors are discussed, as are potential impacts to benthic biomass and production, of declining bottom oxygen, increasing bottom temperature and potential changes in riverine input.

The contamination of surface sediments in Guan River Estuary, China, by polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. Total concentrations of 21 PAHs ranged from 90 to 218ng/g with an average of 132.7ng/g, which is relatively low in comparison with other estuaries around the world. PAH concentrations appeared to be positively correlated with clay content and negatively correlated with sediment grain size. Source identification implied that the PAHs originated mainly from pyrolytic sources. However, source patterns may be continuously changed to a petrogenic origin due to the heavy ship traffic and continuous discharge of oily sewage in this area. The PAH levels were also compared with international Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated low negative effects for most individual PAHs. However, toxic effects related to FLO would occur occasionally in most locations in the estuary.

The upper portion of the meadows of the protected Mediterranean seagrass Posidonia oceanica occurs in the region of the seafloor mostly affected by surf-related effects. Evaluation of its status is part of monitoring programs, but proper conclusions are difficult to draw due to the lack of definite reference conditions. Comparing the position of the meadow upper limit with the beach morphodynamics (i.e. the distinctive type of beach produced by topography and wave climate) provided evidence that the natural landwards extension of meadows can be predicted. An innovative model was therefore developed in order to locate the region of the seafloor where the meadow upper limit should lie in natural conditions (i.e. those governed only by hydrodynamics, in absence of significant anthropogenic impact). This predictive model was validated in additional sites, which showed perfect agreement between predictions and observations. This makes the model a valuable tool for coastal management.