涠洲岛赤潮监控区营养盐变化及其结构特征

Variations and Structure Characteristic of Nutrients in Red -tide Monitoring Area of Weizhou Island

关键词:  赤潮  涠洲岛  营养盐  结构特征  富营养化  时空变化

Key words:  red tide  Weizhou Island  nutrient  structural features  eutrophia  spatial-temporal change

摘要:

通过分析2010-2013年赤潮监测区的营养盐监测数据，运用富营养化评价、空间波动评价以及营养盐限制评价方法研究涠洲岛赤潮监控区营养盐含量时空变化，探讨该海域的营养状况以及结构特征。2010-2013年涠洲岛赤潮监控区营养盐含量未达到富营养化标准。硝酸盐（NO₃-N）和活性磷酸盐（PO₄-P）含量变异系数分别是0.10~0.21和0.11~0.24，空间波动程度在年际间存在显著差异；除2011年S1站点的营养盐含量相对较高外，其余年份各个监测点位之间均差异不大；涠洲岛赤潮监控区表层海水中氮（N）、磷（P）和硅（Si）含量存在明显的月变化特征，4月份表层海水中各类营养盐含量相对较高；监控区氮磷比（N/P值）为28.5：1~57.56：1，活性磷酸盐（PO₄-P）对监控区浮游植物的繁殖生长起着潜在的限制性作用。涠洲岛赤潮监控区营养盐含量在4月份存在高值，为浮游植物的增殖提供基础条件，春夏季风生流对各形态磷（P）含量的补充，缓解海域的磷（P）限制，可能是近年来涠洲岛多次发生赤潮的原因。

Abstract:

Based on the analysis of nutrient monitoring data of red tide monitoring area from 2010 to 2013, the eutrophication evaluation, spatial fluctuation evaluation and nutrient limitation evaluation method were used to study the temporal and spatial variation of nutrient content in the monitoring area of red tide in Weizhou Island, and to explore the nutrient status and structure characteristics. In 2010-2013, the nutrient content in the red tide monitoring area of Weizhou Island did not reach the eutrophication standard. The range of variation coefficients of NO₃-N and PO₄-P content was 0.10-0.21 and 0.11-0.24, respectively. There was a significant difference in spatial fluctuation between years. Except for the relatively high nutrient content in the S1 site in 2011, there was no significant difference among the monitoring sites in the other years. The contents of nitrogen (N), phosphorus (P) and silicon (Si) in the surface seawater of Weizhou Island red tide monitoring area had obvious characteristics of monthly changes. In April, the content of various nutrients in the surface seawater was relatively high. The change of nitrogen/phosphorus ratio (N/P value) in the monitoring area was 28.5:1 to 57.6:1, and the active phosphate (PO₄-P) had a potential limiting effect on the reproduction and growth of phytoplankton in the monitoring area. The content of nutrients in the red tide monitoring area of Weizhou Island had a high value in April, which provided the basic conditions for the proliferation of phytoplankton. The supplementation of the phosphorus (P) by spring and summer wind currents and the alleviation of phosphorus restrictions in the sea may be the reason why the red tide occurred many times in Weizhou Island in recent years.