Based on the data obtained from twenty-two cruises in the last eight years from 2003 to 2010 , long-term variations of nitrate,nitrite,ammonia,inorganic nitrogen,reactive phosphate and silicate in the Tieshangang bay were studied. The result showed,that concentration of inorganic nitrogen ranged from 0. 21 to 47. 86 μmol/L, reactive silicate ranged from 0. 01 to 0. 71 μmol/L and phosphate ranged from 4. 29 to 124. 29 μmol/L,respectively. Spatial distribution of nutrient concentration among stations and the changes in different seasons were variable during the last eight years,and consistent changes in nutrient distribution and seasonal variation were not observed among those years in the Tieshangang bay. Long-term variation of nutrition concentration showed increasing trend from 2003 to 2008 and then decreased, which was a little different from that in the Qinzhou bay. Long-term variations of nutrition in the Tieshangang bay were mainly influenced by river run-off,land pollution and nutrient regeneration.%2003～2010年对广西铁山港湾进行22个航次的调查,采集海水样品分析该港湾硝酸盐氮、亚硝酸盐氮、氨氮、无机氮、活性磷酸盐和活性硅酸盐8年的浓度变化特征和季节变化特征,并结合文献资料,比较该期间铁山港湾与钦州湾海水营养盐浓度变化的异同.结果,2003～2010年间铁山港附近海域无机氮浓度为0.21～47.86μmol/L,活性磷酸盐的浓度为0.01～0.71μmol/L,活性硅酸盐的浓度为4.29～124.29μmol/L.2003～2010年营养盐在各年空间分布和季节变化上没有呈现出一致性,总体上营养盐呈现出从白沙河口及内湾向湾外递减的空间分布特征,季节变化总体上呈现出无机氮丰水期明显高于平水期和枯水期、硅酸盐在丰水期和平水期浓度较高而枯水期较低、磷酸盐在各水期变化不大的特征.2003～2010年间铁山港湾营养盐浓度呈现出先增加后回落的趋势,与钦州湾的逐渐增加趋势不同.铁山港湾营养盐的长期变化主要是受径流、陆源污染和营养盐再生等影响.
展开▼
