NUTRIENTS DISTRIBUTION IN THE MIDDLE-TO-LOW LATITUDE ZONE OF NORTH PACIFIC
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摘要: 探讨了北太平洋中低纬度海区的总有机磷(TOP)、总有机氮(TON)以及无机溶解营养盐的分布规律。分析结果表明,表层水体中TOP和TON含量占TP和TN的大部分,TOP和TON的平均含量分别占TP和TN的57.5%~94.2%和75.0%~98.4%,高值出现在表层,而低值出现在深层水体中。空间分布上,表层海水中的TOP在总磷中所占的比例自西向东是降低的,在20°N附近的西太平洋海区水体中的磷以有机态为主,而10°N附近的东太平洋海区则只占58%~67%。表层水体中不同形态的氮在整个研究区的分布都较为一致,有机氮在总氮中占大部分,通常在75%以上,并在140°W附近出现高值。水体中总氮总磷的比值表明,20°N附近的西太平洋海区,氮磷的比值在Redfield比值附近,说明限制该海区初级生产的因素可能是氮、磷以外的元素;而10°N附近的海区,氮磷比值低于Redfield比值,说明该海区以氮限制为主。总体而言,研究海区的垂直扩散和水平输送以及生物固氮作用,可能是控制研究区这种分布格局的主要原因,TOP和TON对研究海区的初级生产以及营养盐的循环起着显著的作用,是初级生产所需营养的重要来源之一。Abstract: The distribution of total organic phosphorus (TOP),total organic nitrogen (TON),and dissolved inorganic nutrients in the middle-to-low latitude zone of the North Pacific was studied.In general, TOP and TON vary from 0.04 to 1.44 μM,and 0.13 to 26.61 μM respectively.TOP and TON are the major components of TP and TN in the surface water,accounting for 57.5%~94.2% of TP and 75.0%~98.4% of TN respectively,with highest concentrations in the surface water and lowest concentrations in the deeper water.TN:TP ratios in seawater at the stations near 20°N fluctuate around the Redfield ratio, indicating that the primary productivity in this region was limited by other factors instead of nitrogen and phosphorus.The TN:TP ratios in the water column near 10°N were significantly lower than the Redfield ratio,indicating that nitrogen was limited in this region.The joint physical and biological processes control the distribution of TOP and TON in surface water,and biological N2 fixation may play important role in the nitrogen cycle in the region.
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Keywords:
- TOP /
- TON /
- nutrients /
- North Pacific Ocean
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