腺带刺沙蚕的早期发育

１９８３年７—１２月于室内进行了腺带刺沙蚕Ｎｅａｎｔｈｅｓｇｌａｎｄｉｃｉｎｃｔａ人工授精、孵化及幼体培养观察．该种沙蚕在性成熟时没有异沙蚕型出现。水温在１３．０—２９．３℃范围内，沙蚕均能完成胚胎发育和幼体发育。担轮幼虫期在膜内渡过，五刚节疣足幼虫开始摄食，七剧节疣足幼虫开始钻砂，沙蚕幼虫体节在２０节之前体节与体长呈明显的直线正相关。     

Benthic Fluxes of Dissolved Inorganic Nitrogen in a Coastal Lagoon of the Northern Adriatic Sea: an Interpretation of Spatial Variability Based on Sediment Features and Infauna Activity

Abstract. Dark respiration rates, dissolved inorganic nitrogen (DIN) fluxes and nitrification rates were measured at two sites in the microtidal Sacca di Goro lagoon in September 2000. DIN fluxes correlated with the biomass of the dominant macrofauna species (the amphipod Corophium spp. at station Giralda and the polychaete Neanthes spp. at station Faro). Respiration (> 6 mmol O₂ m⁻²h⁻¹) and ammonium fluxes (> 80μmol N m⁻²h⁻¹) were higher at station Giralda despite the lower organic matter content (4.5 %) and lower macrofauna biomass (4 g AFDW m⁻²). At both sites ammonium fluxes were significantly correlated with the biomass of the benthic infauna, but Corophium stimulated ammonium NH₄⁺ fluxes 3-fold compared to Neanthes. The amphipod also enhanced nitrification rates (> 300 μmol N m⁻²h⁻¹) due to the high density of its burrows, the higher NH₄⁺ regeneration rates and the enhanced oxygen supply to the bacteria.     

Toxicity of 1,4-dichlorobenzene in sediments to juvenile polychaete worms

Investigation of sediment contamination associated with a marine sewage outfall in Victoria (BC, Canada) found elevated concentrations of 1,4-dichlorobenzene (1,4-DCB). Juvenile polychaete worm (Neanthes) growth was significantly reduced at or near the outfall, roughly corresponding to elevated 1,4-DCB concentrations. There are few data on 1,4-DCB toxicity to marine organisms and no published literature on its toxicity to benthic marine organisms. To determine whether reduced polychaete growth (measured as dry weight) was due to 1,4-DCB exposure, a laboratory investigation was conducted. Uncontaminated marine sediment was spiked with 1,4-DCB and juvenile Neanthes were exposed in 20-d sublethal toxicity tests. There were no adverse effects on survival at any test concentration; mean survival was 80–100%. Statistically significant decreases in average dry weight only occurred at the highest 1,4-DCB concentration (19,900 μg/kg, dry weight); this represented a 1,4-DCB concentration more than 10 times higher than previously measured at the outfall (1710 μg/kg, dry weight). There were no adverse effects on survival or dry weight at the range of concentrations previously measured in sediments from the vicinity of the outfall.