南极普里兹湾表层沉积物中磷的形态分布特征

针对多次南极考察中雪龙号在普里兹湾海域获取的表层沉积物样品,分析了该海域沉积物中各形态磷的含量,并讨论了其分布特征和控制因素。结果表明,表层沉积物总磷含量介于416.1×10-6—676.3×10-6之间,平均为543.5×10-6,主要由碎屑磷(平均为209.9×10-6)和自生磷(平均为137.7×10-6)组成。自生磷、有机磷呈现从湾东部至西部逐渐降低的分布趋势,这种分布与有机碳、生物硅等生源要素的分布以及上层水体生产力的高低相吻合,指示了其海洋生源属性;碎屑磷在湾西部含量较高,其分布与沉积物中铝、砂质的分布模式一致,表明其主要来自堆积在西部浅滩区域冰山携带的陆源砂质碎屑。可交换态磷(平均为36.0×10-6)和铁结合磷(平均为47.1×10-6)在沉积物中含量较低,分别受沉积物粒度和铁含量的控制,仅在湾东部和中心个别站位含量较高。生物可利用磷在湾东部和中心区域含量较高,可能与上述区域较高的生源颗粒物沉降速率有关,同时这些颗粒物可能吸附了水体中的磷进入沉积物中,导致对应底层海水磷酸盐浓度相对降低。

SPECIATION OF PHOSPHORUS IN SURFACE SEDIMENTS OF THE PRYDZ BAY,ANTARCTICA

Speciation of phosphorus in surface sediments which were collected during several CHINARE cruises in Prydz Bay were investigated. The sequential extraction method(SEDEX) was used to separate and quantify the following five sedimentary P reservoirs: exchangeable phosphorus (ExP), iron phosphorus (FeP), authigenic phosphorus (AuP), detritus phosphorus (DeP) and organic phosphorus (OP). DeP and AuP were the major types of phosphorus in surface sediments, with an average of 37.5% and 25.8% to total P. The obvious positive relationships between OP, AuP and OC, Sibio indicated that they might come from the same source which was mainly from marine biogenic matters. DeP could be observed positively correlated with Al and sandy sediments, which preferences land sources that might be carried by sea ice with current. It was shown that the content and distributions of P in sediments were majorly controlled by the sources of P, also included the grain size of sediments and other physical factors such as sea ice and current．ExP was controlled by grain size of sediments, while FeP was controlled by iron. In addition, either ExP or FeP was a small components in total phosphorus, only 8.9% and 6.5% respectively. Bioavailable phosphorus concentrated in the central and eastern region, with an average content of 37.2% to total P.