Levels of persistent organic pollutants and residual pattern of DDTs in small cetaceans from the coast of São Paulo, Brazil

The State of São Paulo is the most developed area in Brazil and was impacted by persistent organic pollutants for several decades. This study investigated organochlorines in five species of small cetaceans (Pontoporia blainvillei, Stenella frontalis, Sotalia guianensis, Tursiops truncatus and Steno bredanensis) found dead along the coast of São Paulo between 1997 and 2003. DDTs (15.9 μg g⁻¹ lipid; mean for all pooled individuals) and PCBs (8.08 μg g⁻¹) exhibited the highest concentrations in the animals, reflecting large amounts formerly used in Brazil. Lower levels of mirex (0.149 μg g⁻¹), HCB (0.051 μg g⁻¹), CHLs (0.008 μg g⁻¹) and HCHs (0.007 μg g⁻¹) were detected in all species. Residual pattern of DDTs in dolphins suggests that o,p′-DDT is more recalcitrant than p,p′-DDT in the body of the animals and/or the environment. In contrast to p,p′-DDT, residues of o,p′-DDT seem to be preferentially converted into o,p′-DDD rather than o,p′-DDE.     

Microbiological composition of native and exotic clams from Tagus estuary: Effect of season and environmental parameters

The influence of seasonal and environmental parameters on the occurrence of bacteria was investigated in two clam species (Venerupis pullastra and Ruditapes philippinarum), water and sediment from the Tagus estuary. Total viable counts (TVC), Escherichia coli, Salmonella spp. and Vibrio spp. were evaluated during one-year. Overall, significant seasonal variations were found in both sampling sites, especially for E. coli and Vibrio spp. levels. In summer, significantly higher Vibrio spp. levels were found in R. philippinarum and sediment samples, but not in V. pullastra clams and water samples. In contrast, significantly higher TVC and E. coli levels were observed in winter months in water and sediment samples. Salmonella spp. was generally isolated when higher levels of E. coli were detected, particularly in R. philippinarum. This study is useful for authorities to develop monitoring strategies for coastal contamination and to estimate human health risks associated with the consumption of bivalves.     

Differential concentration of Technetium-99 (99Tc) in common intertidal molluscs with different food habits

Concentration of ⁹⁹Tc has been measured in fucoids and molluscs, sampled in a sheltered intertidal at the southwest coast of Norway from February to November 2006. The concentrations of ⁹⁹Tc in molluscs differed significantly between species. The filtering bivalve Mytilus edulis had the lowest concentrations with averages of 2.3-5.9 Bq kg⁻¹ d.w., while the herbivorous gastropods Littorinalittorina, Littorina obtusata and Patella vulgata had higher concentrations. P. vulgata and L. obtusata had the highest concentrations, 40-47 and 26-30 Bq kg⁻¹ d.w., respectively. L. obtusata has a specialized habit of living, and prefers to feed on fucoids. P. vulgata can graze extensively on the fucoid Ascophyllum nodosum when available. Fucoids are known to have very high uptake of ⁹⁹Tc, and this was also found in the present study. The high ⁹⁹Tc-concentrations of L. obtusata and P. vulgata are most likely due to their habit of feeding on fucoids.     

Eutrophication and retention time affecting spatial heterogeneity in a tropical reservoir

Longitudinal heterogeneity in reservoirs is especially related to increase in sedimentation and water transparency along the river/dam axis. Consequently, primary production tends to reach higher values in intermediate regions where there is a balance between the availability of the main resources (light and nutrients) suitable for phytoplankton growth. Many factors such as reservoir morphometry, retention time, thermal stratification and geographical location can affect the boundaries between these regions. The tropical Funil Reservoir (Brazil), despite a low retention time, has experienced severe eutrophication in recent decades, with persistent cyanobacteria blooms. During the course of 1 year, samples were collected at four stations along the reservoir (fluvial, intermediate and lentic compartments) to evaluate if spatial heterogeneity could affect the occurrence and distribution of these blooms along the reservoir. Although the reservoir has a short annual retention time (mean 41.5 days), the typical zonation pattern was observed for the main abiotic variables and phytoplankton abundance. However, higher biomass occurred in the lentic compartment rather than in the intermediate zone. Despite the peculiar heterogeneity in total biomass, the phytoplankton composition and seasonal variability were very similar along the entire reservoir, with a few marked differences only in the fluvial zone. Phytoplankton total biomass in Funil Reservoir was high, even in periods of lower seasonal retention time (around 15 days), and was especially related to high input of nutrients. Moreover, retention time directly affects the spatial heterogeneity of phytoplankton biomass, since strong variability was only observed during the cold-dry season, corresponding to periods of longer retention time (around 80 days). While high availability of nutrients promoted high cyanobacterial biomass in the entire system, the few periods of heterogeneous spatiality seemed to be related to changes in retention time.     

Detection and isolation of p-nitrophenol-lowering bacteria from intestine of marine fishes caught in Japanese waters

To determine the existence of p-nitrophenol (PNP)-lowering bacteria in intestine of Japanese coastal fish, the gastro-intestinal contents were incubated in Brain Heart Infusion (BHI) broth and minimal medium (MM) broths containing 1 mmol/L PNP at 30 °C for 7 days. Among 26 samples of 19 fish species, 17 samples showed a decrease in PNP of 0.5-0.8 mmol/L in BHI broth, but no decrease was shown in MM broth. Eighteen PNP-lowering bacterial strains were isolated from four fishes. All of the strains were identified as Lactococcus lactis subsp. lactis. Three L. lactis strains JS1-3 isolated from Japanese seabass Lateolabrax japonicus showed the highest PNP-lowering activity (0.44 mmol/L). Optimum temperature and pH for the growth and PNP decreasing corresponded with the marine environment. These results suggested that marine fishes have PNP decreasing bacteria in their intestine. These bacteria might protect host fish from toxicities of PNP and PNP related compounds.     

Relationship between differential retention of Escherichia coli and Enterococcus faecalis and variations in enzyme activity in the scallop Patinopecten yessoensis

Uptake of Escherichia coli and Enterococcus faecalis and variations of trypsin amylase activity acid phosphatase and superoxide dismutase in tissue of the scallop Patinopecten yessoensis were detected. The results showed that P. yessoensis accumulated E. faecalis in larger numbers and more rapidly than E. coli, both with the highest concentration in the digestive tract and lowest in hemolymph. Compared to E. coli, all scallops exposed to E. faecalis showed significantly higher trypsin and AMS activity. SOD activity in hemocytes and ACP activity in hemolymph was significantly higher in the treatments with 5 log₁₀CFU/ml E. coli than with E. faecalis. But no significant differences in ACP activity of P. yessoensis exposed to a 3 log₁₀CFU/ml inoculum of both bacteria were recorded. In conclusion, the mass retention of gut microflora in P. yessoensis is positively correlated with digestive enzymes activity and negatively correlated with ACP activity in the hemocyte.     

Short term impact of planktonic mucilage aggregates on macrobenthos along the Istrian rocky coast (Northern Adriatic, Croatia)

During nearly every summer of the last 15 years, massive mucilage aggregations have formed in the water column of the northern Adriatic. The phenomenon also occurred during the summer of 2004, lasting approximately from the middle of June to the end of July. After approximately 20 days of mucilage impact (coverage of the rocky bottom from 40% to 90%), the effects on selected macrobenthic species were assessed at depths of 5-7m. The responses to the mucilage impact were species dependent. Smothering by mucilage caused partial necrosis of the sponge Verongia aerophoba: from 7% to 56% of the colony surface was deteriorated. In contrast, the impact was lethal for the mollusc Arca noae: from 5% to 45% of the molluscs died. Usually, no deleterious effects were ascertained on perennial parts of the thalli (axes) of macroalgae of the genus Cystoseira. However, primary branches showed signs of necrosis, and Cystoseira compressa was more sensitive compared to Cystoseira corniculata and Cystoseira barbata. Apparently, this does not profoundly affect Cystoseira populations, which have been in a phase of expansion along the shallow Istrian rocky coast over the last 15 years.     

Predation effects of benthivorous fish on grazing and shredding macroinvertebrates in a detritus-based stream food web

We investigated lethal and sublethal predation effects of the benthivorous gudgeon (Gobio gobio) on the grazing mayfly Rhithrogena semicolorata and the shredding amphipod Gammarus pulex over 21 months in a largely detritus-based small stream. We hypothesised that shredders are generally less vulnerable to fish predation and therefore less likely to be predation-controlled than grazers, because the latter are visible to the predators during their feeding on stone surfaces, while shredders may hide between leaves during foraging.The hypothesis was tested in two 400 m experimental reaches of a natural stream, which were manipulated in order to contain and to lack fish, respectively. Biomass of G. pulex was significantly reduced in the fish section while that of R. semicolorata was not. Since approximately 91% of the annual production of G. pulex but only 12% of R. semicolorata production was consumed by gudgeon, the observed biomass difference of G. pulex is likely due to a lethal predation effect. However, no sublethal predation effects such as reduced concentration of storage components (triglycerides, glycogen) or reduced reproductive success were observed for both species. Lower mean body length of the R. semicolorata larvae in the fish section did not result in a lower number of eggs in the abdomen of the last instar larvae. Hence, in contrast to our initial hypothesis, in the studied stream the shredder was top-down-controlled, while the grazer was not. It is concluded that top-down control depends on the ecological characteristics of a specific predator-prey pair rather than on trophic guild of the prey.     

Effects of elevated pCO2 on reproductive properties of the benthic copepod Tigriopus japonicus and gastropod Babylonia japonica

We investigated the effects of elevated pCO₂ in seawater both on the acute mortality and the reproductive properties of the benthic copepod Tigriopus japonicus and gastropod Babylonia japonica with the purpose of accumulating basic data for assessing potential environmental impacts of sub-sea geological storage of anthropogenic CO₂ in Japan. Acute tests showed that nauplii of T. japonicus have a high tolerance to elevated pCO₂ environments. Full life cycle tests on T. japonicus indicated NOEC = 5800 μatm and LOEC = 37,000 μatm. Adult B. japonica showed remarkable resistance to elevated pCO₂ in the acute tests. Embryonic development of B. japonica showed a NOEC = 1500 μatm and LOEC = 5400 μatm. T. japonicus showed high resistance to elevated pCO₂ throughout the life cycle and B. japonica are rather sensitive during the veliger stage when they started to form their shells.     

Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal)

The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.     

Urban seagrass: status of Posidonia oceanica facing the Genoa city waterfront (Italy) and implications for management

A system of five adjacent Posidonia oceanica meadows facing the waterfront of Genoa city (Ligurian Sea, NW Mediterranean) was investigated over different spatial scales (meters-kilometers) using three environmental indices: conservation index (CI), substitution index (SI) and phase-shift index (PSI). CI revealed differences mostly at large spatial scale, distinguishing the poor condition of the meadows closest to Genoa centre and harbour from the comparatively healthy condition of the farthest meadows. SI showed differences mostly at small spatial scale (i.e., within meadows), suggesting the influence of local factors in the re-colonisation of regressed meadows by the seagrass Cymodocea nodosa and/or the invasive alga Caulerpa racemosa. Mapping of PSI showed that the meadows closest to Genoa centre and harbour have undergone a nearly total phase shift and have no real potential for recovery: attempts to re-establish P. oceanica there might be a waste of time and money. On the contrary, the meadows farthest from Genoa centre and harbour showed a comparatively low level of phase shift and could still fully recover given specific management actions.     

Recovery of interior brackish marshes seven years after the chalk point oil spill

Seven years after the April 2000 spill of 140,000 gallons of a mixture of No. 6 and No. 2 fuel oils in the Patuxent River, Maryland, heavily oiled brackish marshes showed continuing effects. Stem density and stem height were significantly lower in oiled versus unoiled sites for Spartina alterniflora but not Spartina cynosuroides habitats. In contrast, belowground biomass was significantly lower in S. cynosuroides habitats but not S. alterniflora habitats. Total PAH concentrations were up to 453 mg/kg in surficial soils (0-10 cm) and 2921 mg/kg with depth (10-20 cm). The oil had lost 22-76% of its initial PAH content after seven years, although the oil in marsh soils has undergone little to no additional weathering since Fall 2000. Based on amphipod acute toxicity tests and sediment quality guidelines, 25% of the soils in the marsh are expected to be toxic (ESB-TU_FCV values > 3.0; P_Max > 0.65).     

Occurrence of PSP-producing dinoflagellate Alexandrium tamiyavanichii in Bingo-Nada, the central coastal water of the Seto Inland Sea, Hiroshima Prefecture, Japan

During surveillance of the distribution of the paralytic shellfish poison (PSP)-producing dinoflagellate in 2003, 2004 and 2005 along the coastlines of the Seto Inland Sea, Hiroshima Prefecture, Japan, some species of toxic phytoplankton were isolated from the eastern coasts, Bingo-Nada, the central regions of the Seto Inland Sea. It was rather unexpectedly revealed from the basis of the morphological characteristics that they were unambiguously identified as Alexandrium tamiyavanichii and Alexandrium catenella. Two strains (ATY041106, ATY051018) of A. tamiyavanichii showed a specific toxicity of 38.7 x 10(-6) and 111.5 x 10(-6)MU/cell, respectively. These values seemed to be several times or much higher than that of A. catenella (AC030816, AC040614), having a specific toxicity of 4.5 x 10(-6) and 4.1 x 10(-6)MU/cell, respectively, isolated in the same area. From the results of HPLC-furuorometric analysis, it revealed that the toxins in ATY041106 exist almost exclusively as beta-epimers (C2, GTX3, GTX4), which accounted for 72.7 mol%. The toxin profiles of this strain are featured by the presence of a large amount of GTX3 (59.1 mol%) and a small amount (20.6%) of C1 and 2 in comparison with the PSP compositions of A. tamarense, which is isolated as the main responsible species in Hiroshima Bay, a western part of coastal sea in Hiroshima Prefecture. On the other hand, it revealed that the toxin profiles of two strains (AC030816, AC040614) of A. catenella exist almost exclusively as beta-epimers (C2, GTX3, GTX4), which accounted for 81.8 and 56.5 mol%, as the same manner. The toxin profiles of these two strains are featured by the presence of a large amount of C2 (80.5 and 46.3 mol%) in comparison with the PSP compositions of A. tamiyavanichii. To our knowledge, this is the first record to show the distribution and harmful influence of A. tamiyavanichii and A. catenella in Bingo-Nada in Hiroshima Prefecture. Though contamination of bivalves with these PSP-producing planktons in this area has not occurred yet so far, attention should be paid to this species as well as the other causative dinoflagellate from the stand point of public health and food hygiene.     

Effects of lanthanum(III) and EDTA on the growth and competition of Microcystis aeruginosa and Scenedesmus quadricauda

Rare earth elements (REEs) are widely used to increase crop production in China. However, little attention has been paid to their impacts on aquatic ecology. Batch cultivation was used here to study the effects of lanthanum (La) and EDTA on the growth and competition of the cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus quadricauda. When EDTA was present at a very low concentration (0.269 μmol L⁻¹), low lanthanum concentrations (?7.2 μmol L⁻¹) had little stimulative effect on the growth of M. aeruginosa and S. quadricauda, whereas a high lanthanum concentration (72 μmol L⁻¹) had significant inhibitory effect on both of them. The results of cultivation experiments suggested that the inhibitory effect on M. aeruginosa was higher than that on S. quadricauda and S. quadricauda could become dominant in mixed cultures. When lanthanum was not added to the culture medium, high EDTA concentrations (>13.4 μmol L⁻¹) had a great inhibitory effect on the growth of M. aeruginosa but little effect on the growth of S. quadricauda, which could become dominant in the mixed cultures.Lanthanum and EDTA had complex effects on the growth and competition of M. aeruginosa and S. quadricauda. EDTA did not change the stimulation of low lanthanum concentrations on both, but at intermediated concentrations (2.69-13.4 μmol L⁻¹) it could greatly alleviate lanthanum inhibition on M. aeruginosa; thus, M. aeruginosa would dominate S. quadricauda in these mixed cultures. Lanthanum at low concentration (7.2 μmol L⁻¹) could also alleviate the inhibition of high EDTA on M. aeruginosa, but did not alter the outcome of the competition.     

PCB exposure in sea otters and harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill

Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, whereas concentrations were similar among harlequin ducks from the oiled and unoiled area. Blood enzymes often elevated by xenobiotics were not related to PCB concentrations in sea otters. Only sea otters from the unoiled area had estimated risk from PCBs, and PCB composition or concentrations did not correspond to reported lower measures of population performance in sea otters or harlequin ducks from the oiled area. PCBs probably did not influence limited sea otter or harlequin duck recovery in the oiled area a decade after the spill.     

Do 2006/7/EC European Union Bathing Water Standards exclude the risk of contact with Salmonella or Candida albicans?

The purpose of this study was to evaluate the efficiency of the recent (2006) European Union Directive concerning the management of bathing water quality to exclude the presence of pathogens from complying waters. Coastal water samples were classified according to the Directive. 2.5% of ‘excellent’ water contained Salmonella and 39.2% Candida albicans 11.8% of samples in category ‘good’ were Salmonella positive and 35.2% were C.albicans positive. When the USEPA criterion for marine waters was applied to the same dataset, fewer samples complied, however 6.0% of the complying samples contained Salmonella. The results suggest that the bacterial indicator threshold levels for marine recreational water quality of the 2006/7/EC European Union Directive do not fully exclude contact of bathers with dangerous pathogens. Enterococci, if used as the sole index, appear to form a more reliable proxy of the risk of contact with Salmonella.     

Effects of elevated CO2 on the reproduction of two calanoid copepods

Some planktonic groups suffer negative effects from ocean acidification (OA), although copepods might be less sensitive. We investigated the effect of predicted CO₂ levels (range 480–750 ppm), on egg production and hatching success of two copepod species, Centropages typicus and Temora longicornis. In these short-term incubations there was no significant effect of high CO₂ on these parameters. Additionally a very high CO₂ treatment, (CO₂ = 9830 ppm), representative of carbon capture and storage scenarios, resulted in a reduction of egg production rate and hatching success of C. typicus, but not T. longicornis. In conclusion, reproduction of C. typicus was more sensitive to acute elevated seawater CO₂ than that of T. longicornis, but neither species was affected by exposure to CO₂ levels predicted for the year 2100. The duration and seasonal timing of exposures to high pCO₂, however, might have a significant effect on the reproduction success of calanoid copepods.     

Species- and size-specific variability of mercury concentrations in four commercially important finfish and their prey from the northwest Atlantic

Total mercury was analyzed as a function of body length, season, and diet in four commercially and recreationally important marine fish, bluefish (Pomatomus saltatrix), goosefish (Lophius americanus), silver hake (Merluccius bilinearis), and summer flounder (Paralichthys dentatus), collected from continental shelf waters of the northwest Atlantic Ocean. Mercury levels in the dorsal muscle tissue of 115 individuals ranged from 0.006 to 1.217 μg/g (wet weight) and varied significantly among species. The relationship between predator length and mercury concentration was linear for bluefish and summer flounder, while mercury levels increased with size at an exponential rate for silver hake and goosefish. Mercury burdens were the highest overall in bluefish, but increased with size at the greatest rate in silver hake. Seasonal differences were detected for bluefish and goosefish with mercury levels peaking during summer and spring, respectively. Prey mercury burdens and predator foraging habits are discussed as the primary factors influencing mercury accumulation.     

Assessment of faecal contamination and the relationship between pathogens and faecal bacterial indicators in an estuarine environment (Seine, France)

The Seine estuary, one of the largest estuaries of the European northwest continental shelf, is subjected to numerous anthropogenic influences. Here we present an assessment of the microbial faecal contamination of the estuary water. The most vulnerable areas were defined on the basis of the fluxes of indicator organisms and the occurrence of Salmonella and Cryptosporidium sp. and Giardia sp. (oo)cysts. The microbial quality of the water changes from upstream to downstream: in the upstream area, contamination by faecal-indicator bacteria and Salmonella occurs during periods of high flow; in the urbanized area, mid-way between the uppermost areas of the estuary and its mouth, discharge from a wastewater treatment plant and a tributary degrade water quality; at the estuary mouth, the accumulation of microorganisms attached to particles in the maximum turbidity zone, particularly Clostridium perfringens spores and oocysts of Cryptosporidium, is accompanied by inputs of ThC and Escherichia coli from tributaries. In some areas, significant strong relations are observed between Salmonella, (oo)cysts of protozoan, and levels of faecal indicators.