New primary production in northwest European shelf seas, 1960-2003
New primary production in northwest European shelf seas, 1960-2003
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DOI：
10.3354/meps07460
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发表时间：
2008-01-01
影响因子：
2.5
通讯作者：
Beare, Doug J.
中科院分区：
文献类型：
--
作者：
Heath, Mike R.;Beare, Doug J.
根据硝酸盐浓度的一般相加模型以及关于河流和大气中氧化氮通量的数据，得出了1960年至2003年欧洲西北部陆架海年度潜在新初级生产力的时空模式。平均PNP在季节分层的外陆架区域(>；70gCm(-2)yr(-1))最高，其中来自深水的垂直通量所占的PNP比例(>；65%)与北大西洋涛动(NAO)指数相关。北海中部的PNP最低(接近30gCm(-2)yr(-1))，而北海南部的PNP与河流输入有关，占全年总量的24%(平均类似于50gCm(-2)yr(-1))。大气沉积占整个区域年PNP的3%，但在北海北部，这一比例高于河流的贡献。潮汐前锋传统上被认为是生产力高的地区，但我们发现它们的PNP特征很低，并得出结论，它们一定是高回收生产的地点。结果表明，在20世纪90年代早期，富含硝酸盐的海水异常流入大陆架，这导致了PNP的脉冲与远洋食物网中有据可查的“制度转变”相吻合。整个北海的长期平均PNP大约等于所有较高营养水平的总和，尽管年际变化的营养传播的定义很弱。然而，有理由建议，在PNP低的地区和时期进行收获管理应更加保守，以最大限度地减少对食物网造成有害影响的风险。
Spatial and temporal patterns from 1960 to 2003 in annual potential new primary production (PNP) of the NW European shelf seas were derived from general additive models of nitrate concentrations and from data on riverine and atmospheric fluxes of oxidized nitrogen. Average PNP was highest in the seasonally stratified outer shelf regions (>70 g C m(-2) yr(-1)), where the proportion of PNP accounted for by vertical fluxes from deep water (>65 %) was correlated with the North Atlantic Oscillation (NAO) index. PNP was lowest in the central North Sea (similar to 30 g C m(-2) yr(-1)) and in the southern North Sea was correlated with river inputs that accounted for 24 % of the annual total (average similar to 50 g C m(-2) yr(-1)). Atmospheric deposition accounted for similar to 3 % of annual PNP region-wide, but in the northern North Sea this was higher than the contribution from rivers. Tidal fronts are traditionally considered to be highly productive zones, but we find them to have characteristically low PNP and conclude that they must be loci of high recycled production. The results indicate an exceptional flux of nitrate-rich ocean water onto the shelf in the early 1990s, which resulted in a pulse of PNP coincident with a well-documented 'regime shift' in the pelagic food web. North Sea-wide, long-term average PNP was approximately equal to production by all higher trophic levels combined, though trophic propagation of inter-annual variations was weakly defined. Nevertheless, there is a case for proposing that harvesting in areas and periods of low PNP should be managed more conservatively to minimize the risk of detrimental effects on the food web.