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Hormonal changes, substrate mobilization and energy metabolism were studied in turbot Scophthalmus maximus exposed to 3 hypoxic conditions (oxygen partial pressure in water, PwO sub(2) = 90, 60 and 30 mm Hg) followed by recovery under normoxia. Measurements of the blood pH, total CO sub(2) concentration, arterial oxygen partial pressure, hematocrit, glucose, lactate, and 'stress' hormones (cortisol, adrenaline and noradrenaline) plasmatic concentrations were performed. High-energy phosphorylated compounds, glycogen, glucose and lactate concentrations were also determined in liver and white muscle tissues. Exposure to 90 or 60 mm Hg did not induce any major physiological change, as hyperventilation by itself could compensate for the decrease in water oxygen tension. At 30 mm Hg, marked increases in cortisol, adrenaline and noradrenaline concentrations, associated with a decrease in blood arterial oxygen partial pressure, were observed. During exposure to 30 mm Hg, turbot resorted to anaerobic metabolism, resulting in glycogen depletion and lactate production. This mechanism appeared to be efficient enough to produce energy, as no significant change in phosphorylated compounds and adenylate energy charges in muscle and liver could be observed. These results indicate an absence of metabolic depression in turbot down to 30 mm Hg and confirm the high capacity of this species to cope with low water oxygen tension.

A method for a qualitative analysis of sea urchin diet is based on the characterization of the photosynthetic pigment indices of the major algal groups in the sea urchin gut. The pigments were separated by reverse-phase high performance liquid chromatography (RP-HPLC). This study demonstrated that HPLC is a better method to estimate chlorophyll-a in the gut contents than the conventional spectrophotometric methods which overestimate the amounts by including chlorophyll-a breakdown products. Three sea urchins species, Paracentrotus lividus, Psammechinus miliaris and Sphaerechinus granularis, settled on the loose-lying coralline algae (maerl) in the Bay of Brest (France), were used in this study. The algal pigments identified within the gut contents included chlorophylls-a, -b, -c, fucoxanthin, lutein, βε-carotene and ββ-carotene. The presence of chlorophylls and carotenoid biomarkers was used to characterize the three algal groups: Rhodophyceae, Chlorophyceae, Phaeophyceae in estimating sea urchin diet. The pigment analysis reported here demonstrated that the three species of sea urchins investigated mainly consumed Rhodophyceae which dominate the epibenthic flora in the study area.

A method for a qualitative analysis of sea urchin diet is based on the characterization of the photosynthetic pigment indices of the major algal groups in the sea urchin gut. The pigments were separated by reverse-phase high performance liquid chromatography (RP-HPLC). This study demonstrated that HPLC is a better method to estimate chlorophyll-a in the gut contents than the conventional spectrophotometric methods which overestimate the amounts by including chlorophyll-a breakdown products. Three sea urchins species, Paracentrotus lividus, Psammechinus miliaris and Sphaerechinus granularis, settled on the loose-lying coralline algae (maerl) in the Bay of Brest (France), were used in this study. The algal pigments identified within the gut contents included chlorophylls-a, -b, -c, fucoxanthin, lutein, beta , epsilon -carotene and beta , beta -carotene. The presence of chlorophylls and carotenoid biomarkers was used to characterize the three algal groups: Rhodophyceae, Chlorophyceae, Phaeophyceae in estimating sea urchin diet. The pigment analysis reported here demonstrated that the three species of sea urchins investigated mainly consumed Rhodophyceae which dominate the epibenthic flora in the study area.

Serial photographs emphasize the gradual effects of the Amoco Cadiz oil on the algae of a very polluted sheltered cove near Portsall. The major damage, which was restricted to the algae of high tide levels, appeared to be a function of the duration of their contact with the oil. A noticeable expansion of the Fucus vesiculosus belt down to its lower limit, was the most important fluctuation which appeared in algal zonation during the year following the spill.

Hormonal changes, substrate mobilization and energy metabolism were studied in turbotScophthalmus maximusexposed to 3 hypoxic conditions (oxygen partial pressure in water, PwO² = 90, 60 and 30 mm Hg) followed by recovery under normoxia. Measurements of the blood pH, total CO² concentration, arterial oxygen partial pressure, hematocrit, glucose, lactate, and ‘stress’ hormones (cortisol, adrenaline and noradrenaline) plasmatic concentrations were performed. High-energy phosphorylated compounds, glycogen, glucose and lactate concentrations were also determined in liver and white muscle tissues. Exposure to 90 or 60 mm Hg did not induce any major physiological change, as hyperventilation by itself could compensate for the decrease in water oxygen tension. At 30 mm Hg, marked increases in cortisol, adrenaline and noradrenaline concentrations, associated with a decrease in blood arterial oxygen partial pressure, were observed. During exposure to 30 mm Hg, turbot resorted to anaerobic metabolism, resulting in liver glycogen depletion and lactate production. This mechanism appeared to be efficient enough to produce energy, as no significant change in phosphorylated compounds and adenylate energy charges in muscle and liver could be observed. These results indicate an absence of metabolic depression in turbot down to 30 mm Hg and confirm the high capacity of this species to cope with low water oxygen tension.