New Production and Carbon Cycling in Marine Plankton Systems

从海洋表面输出有机物是一个重要的生物和化学过程。从生物学上讲，这种输出为大多数深层生物提供了食物，从化学上讲，它影响了二氧化碳和氧气等气体与大气的交换。出口通常是用碳来定义的。一种常见的方法是，通过假设每产生一个新的碳原子，就会输出6.6个碳原子，来估计浮游生物总产量的新（硝酸盐）成分等限制性营养物质的碳输出。然而，地表水碳和氮循环之间的齿轮比（雷德菲尔德比率之一）从未被严格检查过。最近对不同海洋区域的测量表明，与新产量相关的无机碳的净变化超过了根据Redfield转换预测的50%以上。因此，目前关于海洋中养分循环的概念可能存在严重缺陷，海洋作为碳汇和氧源的作用可能被严重低估。这项研究首次对溶解无机碳和氧气的新产量和净产量之间的关系进行了定量研究，并进行了孵化实验，可以将生物过程与混合和气体交换的混淆效应分离开来。这些实验将提供更准确地估计海洋碳和氧通量所需的关键关系。碳和氮的差异回收是Redfield C:N转换在地表水中失败的原因，也将进行评估。

The export of organic matter from the ocean's surface is an important biological and chemical process. Biologically, this export feeds most deeper dwelling organisms, and chemically it influences the exchange of gases like carbon dioxide and oxygen with the atmosphere. Export usually is defined in terms of carbon. A common approach is to estimate carbon export from a limiting nutrient such as the new (nitrate) component of total plankton production by assuming that 6.6 atoms of carbon are exported for each atom of new production. However, this gear ratio (one of the Redfield ratios) between the surface water carbon and nitrogen cycles has never been rigorously examined. Recent measurements in diverse ocean areas indicate that the net change in inorganic carbon associated with new production exceeds that predicted from the Redfield conversion by more than 50%. Thus, current concepts or nutrient cycling in the ocean may be seriously flawed and the role or the ocean as a carbon sink and as an O2 source may be significantly underestimated. This research represents the first quantitative study of the relationship between new production and net production in terms of both dissolved inorganic carbon and O2 with incubation experiments that can isolate the biological processes from the confounding effects of mixing and gas exchange. These experiments will provide critical relationships that are needed for more accurate estimates of oceanic carbon and oxygen fluxes. The differential recycling of carbon and nitrogen as a reason why the Redfield C:N conversion fails in surface water will also be evaluated.