Potential effect of sedimentary iron-phosphorus accumulation on frequent algal bloom in the Pearl River Estuary

Science in China Series D: Earth Sciences - Tập 50 - Trang 453-461 - 2007
HuanXin Weng1, XiangWei Sun1, JingFeng Chen1, JianFang Chen2, LiHong Chen2, XiangHua Chen1, YaChao Qin1
1Institute of Environment & Biogeochemistry, Zhejiang University, Hangzhou, China
2Second Institute of Oceanography, State Oceanic Administration, Hangzhou, China

Tóm tắt

Based on laboratory culture of harmful alga on iron and phosphorus uptake, and the study of accumulation of iron-phosphorus in cores and release of iron and phosphorus from surficial sediments collected in the Pearl River Estuary, the reasons of the high frequency of phytoplankton bloom therein are discussed. The results show that Fe starvation can make algal growth rate slow down and the peak of cell number decrease. Fe and P contents in algal cell bear a significant correlation and the molar ratio of P:Fe is ∼356:1, suggesting that algal uptake of Fe and P is synergistic. Total Fe and total P in sediments are positively correlated and Fe-P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34.26%–80.21% of exchangeable P and 4.04%–22.52% of exchangeable Fe are released from surficial sediments, implying that the accumulation of Fe-P in sediments is available for providing nutrients (P and essential Fe) for the demand of phytoplankton bloom. These factors might be responsible for a higher frequency of red tides than other marine regions.

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Science in China Series D: Earth Sciences

Tập 50

453-461

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