Sarradin Pierre-Marie, Lannuzel Delphine, Waeles Matthieu, Crassous Philippe, Le Bris Nadine, Caprais Jean Claude, Fouquet Yves, Fabri Marie Claire, Riso Ricardo
Département Etudes des Ecosystèmes Profonds, Ifremer centre de Brest, BP70, Plouzané, France.
Sci Total Environ. 2008 Mar 15;392(1):119-29. doi: 10.1016/j.scitotenv.2007.11.015.
The distribution of Fe, Cu, Zn, Pb, Cd between the dissolved (<2 microm) and the particulate (>2 microm) fractions was measured after in-situ filtration in two hydrothermal habitats. The total metal concentration ranges exhibit a clear enrichment compared with the seawater concentration, accounting for the hydrothermal input for all the metals considered. Iron is the predominant metal (5-50 microM) followed by Zn and Cu. Cd and Pb are present at the nM level. At the scale studied, the behavior of temperature, pH and dissolved iron is semi-conservative whereas the other dissolved and particulate metals are characterized by non-conservative patterns. The metal enrichment of the >2 microm fraction results from the settlement and accumulation of particulate matter close to the organisms, acting as a secondary metal source. The enrichment observed in the dissolved fraction can be related to the dissolution or oxidation of particles (mainly polymetallic sulfide) or to the presence of small particles and large colloids not retained on the 2 microm frit. SEM observations indicate that the bulk particulate observed is characteristic of crystalline particles settling rapidly from the high temperature smoker (sphalerite, wurtzite and pyrite), amorphous structures and eroded particles formed in the external zone of the chimney. Precipitation of Zn, Cu, Cd and Pb with Fe as wurtzite, sphalerite and pyrite is the main process taking place within the area studied and is semi-quantitative. The distribution of the dominant observed fauna has been related to the gradient resulting from the dilution process, with the alvinellids worms colonizing the hotter and more variable part of the mixing zone, but also to the metallic load of the mixing zone. Dissolved and particulate metal concentrations are therefore necessary abiotic factors to be studied in a multiparametric approach to understand the faunal distribution in hydrothermal ecosystems.
在两个热液生境中进行现场过滤后，测量了铁、铜、锌、铅、镉在溶解态（<2微米）和颗粒态（>2微米）部分之间的分布。与海水浓度相比，总金属浓度范围呈现出明显的富集，这说明了所考虑的所有金属的热液输入情况。铁是主要金属（5 - 50微摩尔），其次是锌和铜。镉和铅的含量处于纳摩尔水平。在所研究的尺度上，温度、pH值和溶解态铁的行为具有半保守性，而其他溶解态和颗粒态金属则表现出非保守模式。>2微米部分的金属富集是由于靠近生物体的颗粒物质的沉降和积累，这充当了二次金属源。溶解部分中观察到的富集可能与颗粒（主要是多金属硫化物）的溶解或氧化有关，或者与未被2微米滤片截留的小颗粒和大胶体的存在有关。扫描电子显微镜观察表明，观察到的大部分颗粒具有从高温烟囱迅速沉降的结晶颗粒（闪锌矿、纤锌矿和黄铁矿）、无定形结构以及在烟囱外部区域形成的侵蚀颗粒的特征。锌、铜、镉和铅与铁以纤锌矿、闪锌矿和黄铁矿的形式沉淀是在所研究区域内发生的主要过程，并且是半定量的。观察到的优势动物群的分布与稀释过程产生的梯度有关，阿尔文虫类栖息在混合区较热且变化较大的部分，但也与混合区的金属负荷有关。因此，溶解态和颗粒态金属浓度是在多参数方法中研究的必要非生物因素，以了解热液生态系统中的动物群分布。
