Monbet Phil, McKelvie Ian D, Worsfold Paul J
Biogeochemistry & Environmental Analytical Chemistry Group, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Plymouth, UK PL4 8AA.
J Environ Monit. 2010 Jan;12(1):296-304. doi: 10.1039/b911429g. Epub 2009 Sep 17.
The speciation of phosphorus in Tamar estuary sediment has been determined at eight stations from Gunnislake (riverine end-member) to Torpoint (marine end-member) using the SEDEX (sedimentary extraction) sequential extraction scheme. The seasonal variability of total phosphorus and each of the five fractions is discussed. Total phosphorus, in the range 26-51 micromol g(-1), was stored in the relatively labile fractions, particularly in the iron oxide fraction. The well oxygenated waters of the macrotidal Tamar estuary ensure that the surface sediment layer remains oxic, providing an effective barrier that retains dissolved reactive phosphorus (DRP) within the sedimentary iron oxide fraction and prevents phosphorus migration from the sediment to the water column. The exchangeable and organic phosphorus sedimentary pools, although small, are therefore the main potential sources of phosphorus release to the water column. In particular, this study shows that exchangeable phosphorus and dissolved organic phosphorus (DOP) in the pore water are intimately linked. Finally, the distribution of phosphorus in the estuary is strongly influenced by particle morphology, with most of the sedimentary phosphorus forms exhibiting significant positive correlations with the percent of each grain size.
利用SEDEX（沉积物提取）连续提取方案，在从冈尼斯拉克（河流端元）到托尔波特（海洋端元）的8个站点测定了塔马河口沉积物中磷的形态。讨论了总磷和五个组分各自的季节变化。总磷含量在26 - 51微摩尔/克范围内，储存在相对不稳定的组分中，特别是在氧化铁组分中。大潮差的塔马河口的富氧水体确保表层沉积层保持有氧状态，形成一道有效的屏障，将溶解态活性磷（DRP）保留在沉积氧化铁组分中，并防止磷从沉积物迁移到水柱中。因此，尽管可交换磷和有机磷的沉积库较小，但却是向水柱释放磷的主要潜在来源。特别是，本研究表明孔隙水中的可交换磷和溶解有机磷（DOP）密切相关。最后，河口磷的分布受颗粒形态的强烈影响，大多数沉积磷形态与各粒径百分比呈显著正相关。
