National and Kapodistrian University of Athens, Department of Chemistry, Laboratory of Environmental Chemistry, Panepistimiopolis Zografou, 157 71 Athens, Greece.
Chemosphere. 2013 Jun;91(11):1590-5. doi: 10.1016/j.chemosphere.2012.12.053. Epub 2013 Jan 24.
Macroalgae are a significant source of extracellular organic material in the coastal areas of the Mediterranean, including organic ligands which serve as modulators of metal complexing capacity. This paper examines the release of copper-complexing ligands by 24 macroalgal species, including chlorophyta, rhodophyta, ochrophyta as well as Posidonia oceanica, common throughout the Mediterranean. Metabolites isolated from the algae Dictyota dichotoma and Pterocladiella capillacea were examined for the first time regarding their Cu-complexing properties. The concentration of ligands (LT) and the copper-binding strength (logKapp) of exudates and metabolites were determined by electrochemical methods. All algal species released ligands giving LT concentrations ranging from 109 to 744 nM in unfiltered samples. An increase in the concentration of ligands up to 15 times in comparison to the blank was observed after 48 h of culturing macroalgae in artificial seawater. The binding strength (log Kapp) varied among species from 7.0 to 8.6, except for the metabolites for which it was lower (log Kapp=6). Most of the ligands released were in the dissolved phase, with the contribution of particulate and/or colloidal organic matter (up to 46% of total ligands) appearing to be important only in specific macroalgal species.
大型藻类是地中海沿海地区细胞外有机物质的重要来源，包括作为金属络合能力调节剂的有机配体。本文研究了 24 种大型藻类（包括绿藻、红藻、褐藻以及地中海常见的波西多尼亚海草）释放铜络合配体的情况。首次研究了来自 Dicyota dichotoma 和 Pterocladiella capillacea 的藻类代谢物的 Cu 络合特性。通过电化学方法测定了分泌物和代谢物中的配体浓度（LT）和铜结合强度（logKapp）。所有藻类物种都释放了配体，在未过滤的样品中，LT 浓度范围为 109 到 744 nM。在人工海水中培养大型藻类 48 小时后，观察到配体浓度增加了 15 倍。结合强度（log Kapp）在物种间从 7.0 到 8.6 不等，除了代谢物的结合强度较低（log Kapp=6）。释放的大多数配体处于溶解相，颗粒和/或胶体有机物质的贡献（高达总配体的 46%）似乎仅在特定的大型藻类物种中很重要。
