营养盐和光照对浮游植物群落结构的影响

2006年4月在沙埕港湾口处网箱养殖区,研究营养盐和光照对浮游植物类群及其优势种生长的影响。结果表明,微、小型浮游植物在100%自然光强下生长最快,微微型浮游植物在50%自然光强下生长最快。在各形态无机氮（N）、磷（P）营养盐存在的情况下,浮游植物会首先利用氨氮（NH4-N）,但培养后期NH4-N加富组的浮游植物丰度低于亚硝酸盐（NO2-N）加富组和硝酸盐（NO3-N）加富组。营养盐加富在短期内引起浮游植物数量的快速增加,当营养盐浓度达到一定水平后对浮游植物的生长不利,其抑制作用随浮游植物种类而异;随着营养盐消耗,浮游植物的数量和多样性均下降。微、小型浮游植物丰度与NO3-N、N/P呈显著相关,相关系数分别为-0.625、0.521;微微型浮游植物丰度与磷酸盐（PO4-P）呈显著相关,相关系数为0.530。

Influences of nutrients and illuminance on phytoplankton community structure

Influences of nutrients and illuminance on phytoplankton community and its dominant species were studied at the net cage aquaculture area in the baymouth of Shacheng Harbour in April,2006.The main results were as follows：micro-nanophytoplankton got best growth under 100% natural illumination,while picophytoplankton got best growth under 50% natural illumination.Ammonia nitrogen was first utilized at the presence of different forms of nutrients,but afterwards the phytoplankton abundance in ammonia-nitrogen enrichment group was lower than that of nitrite and nitrate enrichment groups.Nutrients enrichment caused rapid growth of phytoplankton in a short time,but it inhibited phytoplankton growth when it exceeded a certain level and the inhibition was associated with the phytoplankton species.Phytoplankton abundance and biodiversity decreased as nutrients were consumed.Micro-nanophytoplankton abundance was significantly correlated with nitrate and nitrogen-phosphorus ratio,with correlation coefficients of-0.625 and 0.521 respectively.Picophytoplankton was significantly correlated with phosphate,with correlation coefficient of 0.530.