Phytoplankton primary production in the world's estuarine-coastal ecosystems
Phytoplankton primary production in the world's estuarine-coastal ecosystems
复制标题
DOI：
10.5194/bg-11-2477-2014
复制
发表时间：
2014-01-01
期刊：
影响因子：
4.9
通讯作者：
Kleckner, A. E.
中科院分区：
文献类型：
--
作者：
Cloern, J. E.;Foster, S. Q.;Kleckner, A. E.
河口是生物地球化学的热点，因为它们从陆地和海洋获得大量营养物质和有机碳的输入，以支持高新陈代谢和初级生产。我们综合了公布的年度浮游植物初级生产量(APPP)在海洋生态系统中的速率，这些生态系统受到与陆地河口、海湾、泻湖、峡湾和内海的连通性的影响。对科学文献的回顾产生了1148个APPP值的汇编，这些值来自每月的孵化分析，以测量碳同化或氧气产生。131个生态系统的APPP测量中位数为185，平均值为252GCM(-2)年(-1)，但范围很大：从-105(谢尔德河口的浮游净生产量)到1890g厘米-2年(-1)(玉马川口的浮游植物净生产量)。APPP在生态系统内的变化高达10倍，每年变化5倍(但我们只发现了8个长于10年的APPP系列，因此我们对十年尺度变化的了解有限)。我们利用对个别地区的研究来建立一个概念性模型，将产生这种巨大变化的机制整合在一起：营养物质供应、浑浊对光的限制、消费者的放牧以及物理过程(河流流入、海洋交换以及热能、光能和风能的输入)。我们认为方法是可变性的另一个来源，因为编译包括从差异很大的协议派生的值。模拟模型表明，文献中报道的不同方法可以产生高达3倍的变异性，这取决于孵化协议和随时间和深度积分测量的速率的方法。尽管有人试图扩大河口沿海APPP的测量范围，但经验记录不足以产生可靠的全球估计。这一记录在三个方面存在缺陷。首先，在北欧(特别是波罗的海地区)和北美进行的大量测量是高度偏颇的。在1148个报告的APPP值中，958个来自北纬30度至60度之间的站点；我们发现只有36个站点位于北纬20度以南。第二，在已报告APPP的131个生态系统中，37%的数据仅基于一年中一个位置的测量。考虑到生态系统的年际和空间变异性很大，这些值的准确性尚不清楚，但可能较低。最后，全球评估因采用不同的方法而不能相互比较而造成混乱。大陆边缘的浮游植物初级生产量与水质的变化、包括海洋-大气二氧化碳交换在内的生物地球化学过程以及较高营养水平的生产量(包括我们作为食物捕捞的物种)密切相关。经验记录存在缺陷，无法对这一关键的地球系统进程进行可靠的全球评估。我们在解决这些不足方面面临两大挑战：(1)组织和资助一项国际努力，以使用一种共同的方法，并在具有全球代表性和随时间持续的沿海站点网络上定期衡量APPP，以及(2)将数据整合到一个统一的模型中，以解释生态系统之间的广泛变异性，并随着全球变化的不断展开，预测APPP对区域表现的反应。
Estuaries are biogeochemical hot spots because they receive large inputs of nutrients and organic carbon from land and oceans to support high rates of metabolism and primary production. We synthesize published rates of annual phytoplankton primary production (APPP) in marine ecosystems influenced by connectivity to land - estuaries, bays, lagoons, fjords and inland seas. Review of the scientific literature produced a compilation of 1148 values of APPP derived from monthly incubation assays to measure carbon assimilation or oxygen production. The median value of median APPP measurements in 131 ecosystems is 185 and the mean is 252 gCm(-2) yr(-1), but the range is large: from -105 (net pelagic production in the Scheldt Estuary) to 1890 g Cm-2 yr(-1) (net phytoplankton production in Tamagawa Estuary). APPP varies up to 10-fold within ecosystems and 5-fold from year to year (but we only found eight APPP series longer than a decade so our knowledge of decadal-scale variability is limited). We use studies of individual places to build a conceptual model that integrates the mechanisms generating this large variability: nutrient supply, light limitation by turbidity, grazing by consumers, and physical processes (river inflow, ocean exchange, and inputs of heat, light and wind energy). We consider method as another source of variability because the compilation includes values derived from widely differing protocols. A simulation model shows that different methods reported in the literature can yield up to 3-fold variability depending on incubation protocols and methods for integrating measured rates over time and depth.Although attempts have been made to upscale measures of estuarine-coastal APPP, the empirical record is inadequate for yielding reliable global estimates. The record is deficient in three ways. First, it is highly biased by the large number of measurements made in northern Europe (particularly the Baltic region) and North America. Of the 1148 reported values of APPP, 958 come from sites between 30 and 60 degrees N; we found only 36 for sites south of 20 degrees N. Second, of the 131 ecosystems where APPP has been reported, 37% are based on measurements at only one location during 1 year. The accuracy of these values is unknown but probably low, given the large interannual and spatial variability within ecosystems. Finally, global assessments are confounded by measurements that are not intercomparable because they were made with different methods.Phytoplankton primary production along the continental margins is tightly linked to variability of water quality, biogeochemical processes including ocean-atmosphere CO2 exchange, and production at higher trophic levels including species we harvest as food. The empirical record has deficiencies that preclude reliable global assessment of this key Earth system process. We face two grand challenges to resolve these deficiencies: (1) organize and fund an international effort to use a common method and measure APPP regularly across a network of coastal sites that are globally representative and sustained over time, and (2) integrate data into a unifying model to explain the wide range of variability across ecosystems and to project responses of APPP to regional manifestations of global change as it continues to unfold.