2013年莱州湾海域营养盐的平面分布及季节变化规律

依据2013年6、8、10、11月对莱州湾4个航次的调查资料,分析了该海域不同季节溶解无机氮(DIN)、活性磷酸盐(PO4-P)平面分布及季节变化特征。结果表明,2013年莱州湾DIN和PO4-P均呈现出较明显的季节差异。其中,夏季受陆源输入显著影响,DIN和PO4-P浓度最高,50%的站位DIN含量超四类海水水质标准;其次为秋季,45%的站位DIN含量超四类海水水质标准,而春季最低,31.25%的站位DIN含量超四类海水水质标准。4个月份PO4-P含量均满足一类海水水质标准。N/P比值总体处于较高水平,表明整个莱州湾海域处于磷限制潜在性富营养(ⅥP)水平。

Distribution and seasonal variation in nutrients in Laizhou Bay,2013

Based on field data of nutrients observed in Laizhou Bay during June,August,October and September,2013,distribution and seasonal variations of dissolved inorganic nitrogen and phosphorus in Laizhou Bay were analyzed in the present study.The results showed that DIN and PO4-P concentrations both presented significant seasonal differences in Laizhou bay,2013.And the DIN and PO4-P values peaked in August during our investigations,which were mainly influenced by the terrestrial input,even the DIN concentration over 50% of survey stations exceeded the fourth class of seawater quality standard.Followed by nutrient values in autumn,approximate 45% of investigating stations with DIN levels exceeded the fourth class of seawater quality standard.Whereas the DIN and PO4-P values performed the minimum in June,only 31.25% of stations with DIN concentrations over the fourth class of seawater quality standard.As for PO4-P concentration,it satisfied the first class of seawater quality standard during the four cruises.Generally,the N/P ratios of the four investigations were in high value,indicating that the phytoplankton growth in Laizhou Bay was potentially limited by phosphorus in 2013.