The Estuary of Bahía Blanca (EBB), Argentina, is an important wetland under intense sewage pollution. We investigated the occurrence of Clostridium perfringens (CP) in populations of two benthic crabs (Neohelice granulata and Cyrtograpsus angulatus) and in sediment from the EBB. CP was found in 49.1% of the crabs and all of the isolates were identified as type A. The alpha (cpa) and enterotoxin (cpe) encoding genes were identified. Genetic analyses identified 13 novel sequence types, and found no clustering among isolates, suggesting that CP is not part of the crabs’ commensal flora. CP carriage was 51 times more likely in crabs from the area nearest sewage outfalls compared with crabs from a reference site. Our in vitro experiments suggest that the carriage of CP in crabs is transient. The use of these benthic crabs as monitoring organisms of sewage pollution in coastal habitats is proposed.

Results show that Microcystis aeruginosa can utilize both dissolved organic phosphorus (DOP) and orthophosphate (DIP) even under low phosphorus (P) conditions to sustain its growth. Total P concentrations decreased markedly in all three P source treatments. Alkaline phosphatase activity (APA) in the different P sources tested changed in response to the DOP and DIP. The APA of DOP groups remained low after decreasing significantly, but the APA in the DIP treatments remained high during the period of culture. Changes in APA at different PO43−–P concentrations in a culture medium revealed negative correlations between APA and DIP. However, a positive relationship was observed between APA and DOP under low P concentrations. These findings indicate that M. aeruginosa can regulate its physiological metabolism to acclimate to low ambient DIP environments.

A survey among beachgoers was conducted to determine the swimming associated health effects experienced and its relationship with beach water exposure behaviour in Morib beach. For beach water exposure behaviour, the highest frequency of visit among the respondents was once a year (41.9%). For ways of water exposure, whole body exposure including head was the highest (38.5%). For duration of water exposure, 30.8% respondents prefer to be in water for about 30min with low possibilities of accidental ingestion of beach water. A total of 30.8% of beachgoers in Morib beach were reported of having dermal symptoms. Bivariate analysis showed only water activity, water contact and accidental ingestion of beach water showed significant association with swimming associated health effects experienced by swimmers. This study output showed that epidemiological study can be used to identify swimming associated health effects in beach water exposed to faecal contamination.

Juvenile flounders (Platichthys flesus), collected in two estuaries with similar temperature regimes (the heavily polluted Seine and the moderately contaminated Vilaine), were submitted to a common garden experiment. After an acclimation period, both populations were challenged by a thermal stress (9–24°C for 15days, then maintenance at 24°C for 19days). The condition factor of the Vilaine fish increased in both conditions, while it decreased for the heated Seine flounders after 34days. The expression of genes related to the energetic metabolism was measured in the liver. The expression levels for ATP-F0 and COII were significantly reduced for heated vs. standard fish from both estuaries, while a decrease of the 12S expression was detected only in heated vs. standard fish from the Seine estuary. Thus, it is suggested that highly contaminated fish from Seine could display a lower tolerance to thermal stress, compared to moderately contaminated fish from Vilaine.

546 Vibrio isolates from rearing seawater (292 strains) and intestines of abalone (254 strains) were tested to ten antibiotics using Kirby–Bauer diffusion method. Resistant rates of abalone-derived Vibrio isolates to chloramphenicol (C), enrofloxacin (ENX) and norfloxacin (NOR) were <28%, whereas those from seawater showed large fluctuations in resistance to each of the tested antibiotics. Many strains showed higher resistant rates (>40%) to kanamycin (KNA), furazolidone (F), tetracycline (TE), gentamicin (GM) and rifampin (RA). 332 isolates from seawater (n=258) and abalone (n=74) were resistant to more than three antibiotics. Peaked resistant rates of seawater-derived isolates to multiple antibiotics were overlapped in May and August. Statistical analysis showed that pH had an important effect on resistant rates of abalone-derived Vibrio isolates to RA, NOR, and ENX. Salinity and dissolved oxygen were negatively correlated with resistant rates of seawater-derived Vibrio isolates to KNA, RA, and PG.

Stable carbon and nitrogen isotope ratios were measured in young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, collected from several Rhode Island, USA estuarine systems. These included three coastal lagoons, an estuarine river and Narragansett Bay. The δ13C trends observed along transects in several systems showed isotopically depleted terrestrial signals in the upper reaches of the estuaries. Significant differences (P<0.05) in δ15N were observed among all estuarine systems and these differences correlated (P<0.01) with human population densities in the watersheds. Although Narragansett Bay has a strong north–south gradient in nutrient concentrations this trend was not reflected in flounder δ15N. The northernmost station with the highest nutrient concentrations unexpectedly had significantly lower δ15N values. Depleted δ15N values at this nutrient-rich station may indicate that concentration-dependent fractionation needs to be considered when using nitrogen isotope ratios in biota to monitor anthropogenic nitrogen inputs in systems with high nitrogen loadings.

Mercury (Hg) and selenium (Se) concentrations were evaluated in a planktivorous fish and four size classes of organisms (FSCO), collected at an oligotrophic bay in the Southeastern Brazilian coast. No significant spatial differences between Hg and Se were found in the FSCO within the five sampling points in the bay. Hg and Se concentrations increased with successive increases in the size class of the analyzed plankton, i.e. approximately 3-and 2-fold, respectively, from microplankton to macroplankton. Hg and Se biomagnified throughout the planktonic food web. The smallest size class of organism, seston, composed of both biotic and abiotic portions, and fish showed the highest Hg concentrations. This indicates that Hg is not biomagnifying in the base of the bay food web. Selenium concentrations in fish were approximately 5.9 times higher than those in seston. Hg and Se concentrations in fish were approximately 3.5 and 14.6 times higher than those found in the plankton, respectively.

Heavy metal (Cu, Pb, Zn, Cr, Cd, As) concentrations, distribution and bioaccumulation were studied in marine organisms in Guangdong coastal regions. Heavy metal concentrations and distribution in organisms showed characteristics according to areas and species. Heavy metal concentrations in most organisms were higher in west than in east, tightly related to the local industry structure and the disequilibrium of metal discharge. Generally, high heavy metal concentrations were detected in molluscs and low concentrations were detected in fish. Bioaccumulation factor was used to assess the accumulation level of marine organisms to heavy metals, of which Cd, Cu and As were the most accumulated elements. Accumulation abilities to heavy metals varied among organism species, such as Distorsio reticulate accumulating Cu, Zn, Cd, As, Loligo beka Sasaki accumulating Pb, Cu, Cr, and Turritella bacillum Kiener accumulating Zn, Cd, As. By comparison, Johnius belengeri, Argyrosomus argentatus, Cynoglossus sinicus Wu had relatively low accumulation abilities.

The ballast waters from ships pose a major threat to oceans, notably because of the spread of microorganisms. The present study evaluates the techno-economic feasibility of implementing the membrane process to remove microalgae from seawater to be ballasted in a single step during planktonic bloom. The optimal conditions for the microfiltration of complex and reproducible synthetic seawater are a permeate flux and specific filtered volume of 100L.h−1.m−2 and 75L.m−2.cycle−1, respectively. Recovery of the membrane process represents about 76.6% and 62.7% of the annual cost for a cruise ship (5400 passengers) and liquefied natural gas (LNG) carrier (75,000m3 of liquid natural gas), followed by the membrane replacement cost (13.4% and 21.9%, respectively). The treatment costs are competitive with conventional treatments, even when the membrane process is more feasible for cruise ships due to its smaller capital cost and footprint.

This work investigates the dependence of the sampling rate (Rs) of semi-permeable membrane devices (SPMDs) on flow rate and temperature. The in situ Rs values were obtained using performance reference compounds (PRCs) with weighted polynomial regression and used to estimate the bioavailable polycyclic aromatic hydrocarbon (PAH) concentrations in seawater. The in situ Rs values did not vary with flow rate and temperature. The empirical equation of the Rs value from the SPMDs was established. This infers that PRCs could be avoided by using an established empirical equation under similar field conditions. The sum of the bioavailable PAHs ranged from 0.281 to 0.611ngL−1 on the eastern side of the Taiwan Strait and from 0.438 to 1.10ngL−1 on the western side. Distinct sources and toxicity of these bioavailable PAHs were observed and mainly resulted from different types of energy consumption.