Nutrient budget for the Eastern Mediterranean: Implications for phosphorus limitation
Nutrient budget for the Eastern Mediterranean: Implications for phosphorus limitation
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DOI：
10.4319/lo.2004.49.5.1582
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发表时间：
2004-09-01
影响因子：
4.5
通讯作者：
Mantoura, RFC
中科院分区：
文献类型：
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作者：
Krom, MD;Herut, B;Mantoura, RFC
东地中海深水中硝酸盐与磷酸盐（N：P）的比例很高（接近28：1），初级生产力的P限制非常罕见。我们提出了一个详细的输入到流域的营养收支，这表明有一个高的N：P比（>16：1）在所有的输入源，特别是从大气源，其中N：P比为117：1。高的N：P比保留在系统内，因为没有显着的反硝化作用，无论是在沉积物或中间水。这是因为该系统的极端贫营养性质，这是由不寻常的反河口流在西西里海峡。东地中海深水中氮磷比接近16：1的唯一区域是亚得里亚海北方，这也是唯一具有显著反硝化作用的区域。氮收支（流域总输入与西西里海峡的净输出）接近平衡。这种氮平衡表明，在这种磷限制系统中，氮固定是一个不显著的过程。深水硝酸盐和颗粒有机氮中异常轻的N-15值可以用固氮作用以外的过程来解释。这些过程包括缺乏显着的反硝化作用在盆地和颗粒有机物出口从表面沃茨在磷限制冬季浮游生物水华。
The eastern Mediterranean has a high nitrate to phosphate (N:P) ratio (similar to28:1) in the deep water and a highly unusual P limitation of the primary productivity. We present a detailed nutrient budget of inputs to the basin, which shows that there is a high N: P ratio (>16:1) in all the input sources, particularly from the atmospheric source, where the N: P ratio was 117:1. The high N: P ratio is retained within the system because there is no significant denitrification in either the sediments or intermediate water. This is because of the extreme oligotrophic nature of the system, which is caused by the unusual anti-estuarine flow at the Straits of Sicily. Support for this conclusion is provided by the observation that the only area of the eastern Mediterranean where the N: P ratio in deeper water is similar to16:1 is the northern Adriatic, which is also the only area with significant denitrification. The N budget (total input to basin vs. net output at the straits of Sicily) balances closely. This N balance suggests that N fixation is an insignificant process in this P-limited system. The unusually light N-15 values in the deep water nitrate and particulate organic nitrogen can be explained by processes other than nitrogen fixation. These processes include a lack of significant denitrification in the basin and by particulate organic matter exported from surface waters during the P-limited winter plankton bloom.