The complexity of the relationships between Alexandrium minutum (A.m.) concentration in the water ([A.m.]w), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP]dg) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters’ valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10×10³cellsml⁻¹ (experiment-1) and 5×10³cellsml⁻¹ (experiment-2): 100% A.m.; 50% A.m.–50% H.t.; 25% A.m.–75% H.t.; 100% H.t. At the end of experiment-2, [PSP]dg were measured. At 10×10³cellsml⁻¹, the microalgal ingestion decreased (p<0.05) with increasing [A.m.]w but not at 5×10³cellsml⁻¹ (p>0.05). The frequency of microclosures specifically increased with [A.m.]w (p<0.05) and the opening duration with [PSP]dg (p<0.0001). Oysters exhibiting the maximum increase in opening duration also exhibited the highest [PSP]dg. The results are discussed in terms of oyster physiology and origin of the behavioral response.

Regulators need a reliable, precise and easy to use tool for predicting the occurrence of pesticides in drain water and catchments in agricultural areas. Occurrence depends on a wide range of substance and site specific factors and this study presents a simple model built on the results from simulations of a detailed model system that does not neglect or omit any of these factors. A drainage dominated sub-catchment (0.03 km²) of the Lillebaek catchment (4.4 km²) on Funen, Denmark, represented by the catchment model MIKE SHE is considered. Detailed analyses have been made with respect to geological and hydrodynamic conditions as well as measurements of pesticide concentrations in ground and surface waters. Maximum concentrations in drain water, the time for reaching this concentration and the time interval for exceeding the limit value have been derived empirically from MIKE SHE simulations using degradation rates and sorption coefficients values for 37 pesticides included in the Danish PATE database. The relatively hydrophilic bentazon and hydrophobic pendimethalin are used as model pesticides for illustration. A simple tool applicable for a wide range of pesticides has thus been designed based on detailed analyses of a limited number of pesticides. The user requirements are degradation rates, sorption coefficients, application rates and regulatory limit values for the pesticides of interest.

Meteorological factors affecting concentration of dissolved inorganic nitrogen in rain were examined. Rain samples were collected on an event basis from a location 100 km east of the Los Angeles Basin. Analysis of the data demonstrated a double decay function where small increases in rain volume resulted in large decreases in nitrogen concentration. In separate time series collections of individual storms, storm wind direction also influenced nitrogen concentrations

Samples of pig slurry, as well as dairy and poultry manures collected in Brittany (western France) were analysed to test the ability of sterol profiles to provide a fingerprint of pig slurry contribution to soil organic matter. The data show that the 5β-stanol, known as coprostanol, is the most abundant sterol present in pig slurry, whereas this compound occurs only in minor amounts in both poultry and dairy manures. Moreover, systematic variations of (campesterol + sitosterol)/cholesterol (i.e., C₂₈₊₂₉/C₂₇) and (coprostanol + epi-coprostanol)/cholesterol (i.e., 5β/C₂₇) ratios allow to discriminate clearly pig slurry from poultry and dairy manures. The robustness of the pig slurry “sterol fingerprint” was tested by analysing the sterol profiles of soil samples from an experimental field that had received a massive pig slurry input between 10 to 14 years ago. The results indicate that the specific sterol profile of pig slurry is conservative once the slurry has been incorporated into the soil. In particular, the diagnostic 5β/C₂₇ ratio proves to be constant with time in soils having received pig slurry application, even 10 years after the end of the application. The “sterol fingerprint” of pig slurry is thus sufficiently distinctive from dairy and poultry manures, and also sufficiently time-resistant, to be of diagnostic value in determining whether a soil sample was once contaminated by pig slurry.

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.

Most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-CO(2) due to ocean acidification (OA) process. Analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool to examine these physiological symptoms at molecular level, but its applications are inadequate. To address this knowledge gap, 2-DE coupled with mass spectrophotometer was used to compare the global protein expression pattern of oyster larvae exposed to ambient and to high-CO(2). Exposure to OA resulted in marked reduction of global protein expression with a decrease or loss of 71 proteins (18% of the expressed proteins in control), indicating a wide-spread depression of metabolic genes expression in larvae reared under OA. This is, to our knowledge, the first proteome analysis that provides insights into the link between physiological suppression and protein down-regulation under OA in oyster larvae.

We evaluated the impact of ocean acidification on the early development of sea cucumber Apostichopus japonicus. The effect of pH-levels (pH 8.04, 7.85, 7.70 and 7.42) were tested on post-fertilization success, developmental (stage duration) and growth rates. Post-fertilization success decreased linearly with pH leading to a 6% decrease at pH 7.42 as compared to pH 8.1. The impact of pH on developmental time was stage-dependent: (1) stage duration increased linearly with decreasing pH in early-auricularia stage; (2) decreased linearly with decreasing pH in the mid-auricularia stage; but (3) pH decline had no effect on the late-auricularia stage. At the end of the experiment, the size of doliolaria larvae linearly increased with decreasing pH. In conclusion, a 0.62 unit decrease in pH had relatively small effects on A. japonicus early life-history compared to other echinoderms, leading to a maximum of 6% decrease in post-fertilization success and subtle effects on growth and development.

Sea cucumbers are dominant invertebrates in several ecosystems such as coral reefs, seagrass meadows and mangroves. As bioturbators, they have an important ecological role in making available calcium carbonate and nutrients to the rest of the community. However, due to their commercial value, they face overexploitation in the natural environment. On top of that, occurring ocean acidification could impact these organisms, considered sensitive as echinoderms are osmoconformers, high-magnesium calcite producers and have a low metabolism. As a first investigation of the impact of ocean acidification on sea cucumbers, we tested the impact of short-term (6 to 12 days) exposure to ocean acidification (seawater pH 7.7 and 7.4) on two sea cucumbers collected in SW Madagascar, Holothuria scabra, a high commercial value species living in the seagrass meadows, and H. parva, inhabiting the mangroves. The former lives in a habitat with moderate fluctuations of seawater chemistry (driven by day-night differences) while the second lives in a highly variable intertidal environment. In both species, pH of the coelomic fluid was significantly negatively affected by reduced seawater pH, with a pronounced extracellular acidosis in individuals maintained at pH 7.7 and 7.4. This acidosis was due to an increased dissolved inorganic carbon content and pCO2 of the coelomic fluid, indicating a limited diffusion of the CO2 towards the external medium. However, respiration and ammonium excretion rates were not affected. No evidence of accumulation of bicarbonate was observed to buffer the coelomic fluid pH. If this acidosis stays uncompensated for when facing long-term exposure, other processes could be affected in both species, eventually leading to impacts on their ecological role.