Collaborative Research: Measuring Ocean Productivity from the Diurnal Change in Oxygen and Carbon

海洋初级生产的速度是海洋食物网的基础，也是碳从地表水向深海移动的基础，这被称为生物泵。然而，人们对初级生产力的时空变化知之甚少，因为目前测量初级生产力的方法需要付出巨大的努力，限制了其应用，而且该方法存在难以量化的偏差。使用一种新颖的方法组合，研究人员将在三个生态不同的地点估计海洋的每日初级生产力。该研究将显著提高对初级生产力变化及其对海洋生物泵影响的理解，这将有利于参与碳循环建模的更广泛的海洋群落，并通过海洋初级生产力对大气二氧化碳吸收和未来气候变化的影响使社会受益。研究结果将被纳入两所大学的本科和研究生课程以及外展讲座中。俄勒冈州立大学和华盛顿大学的本科生都将积极参与该项目。在过去的十年中，一种基于测量溶解氧（O2）气体同位素组成的原位初级生产力方法在海洋学界得到了广泛的应用，因为它可以从简单的水样收集中获得初级产量估计。这种方法根据机遇号船只正在进行的表层海洋采样，得出了全流域初级生产力的快照。然而，需要对初级生产力期间产生的氧/颗粒有机碳（O2/POC）进行准确估计，才能将基于氧的初级生产率转化为碳产量。在该项目中，将通过连续测量氧/氩溶解气体比和POC的日循环来估计三个海洋表层的每日原位初级生产力，并与同时进行的体外初级生产力估计进行比较。将确定初次生产期间产生的O2/POC的变化。基于O2和POC日循环测量的自主浮子估计初级产量将通过基于船舶的测量进行验证。基于本研究产生的自主测量的初级生产力估计有可能彻底改变我们对海洋初级生产力时空变化的认识。

The rate of primary production in the ocean is fundamental to the ocean's food web and the movement of carbon from surface waters to the deep ocean, known as the biological pump. Yet spatial and temporal variations in primary productivity are poorly known because the effort required for the current method of measuring primary productivity is significant, limiting its application, and the method has biases that are difficult to quantify. Using a novel combination of approaches, the investigators will estimate daily primary productivity in the ocean at three ecologically distinct sites. The research will significantly improve understanding of primary productivity variations and their impact on the ocean's biological pump, which will benefit the broader ocean community involved in carbon cycle modeling and benefit society via the impact of ocean primary productivity on atmospheric carbon dioxide uptake and future climate change. The research results will be incorporated into both undergraduate and graduate course curricula and outreach talks at the two institutions. There will be active undergraduate student participation in the project at both Oregon State University and the University of Washington.Within the last decade, an in-situ primary productivity method based on measuring the isotopic composition of dissolved oxygen (O2) gas has gained traction within the oceanographic community because it yields a primary production estimate from a simple water sample collection. This method has yielded basin-wide snapshots of primary productivity based on underway sampling of the surface ocean by ships of opportunity. However, accurate estimates of oxygen/particulate organic carbon (O2/POC) produced during primary productivity are needed to convert oxygen-based primary production rates to carbon production. In this project, daily in-situ rates of primary production in the surface ocean at three ocean sites will be estimated from continuous measurements of diurnal cycles in the oxygen/argon dissolved gas ratio and POC and compared to simultaneous in vitro primary productivity estimates. Variations in the O2/POC produced during primary production will be determined. Autonomous float-based estimates of primary production based on measurements of diurnal cycles in O2 and POC will be validated using ship based measurements. Estimates of primary production based on autonomous measurements resulting from this research have the potential to revolutionize our knowledge on the spatial and temporal variations in primary productivity in the ocean.