Biological processes in the mesopelagic zone of the North Pacific: active carbon transport

海洋生态学家面临的一个重大挑战是，要能够预测气候变化对海洋特别是深海水层生态系统的影响，包括酸化、变暖和氧气减少。从上层真光层到深层沃茨的生物碳去除，称为生物泵，在确定地表二氧化碳交换方面发挥着可变但重要的作用。从真光层被动和主动输出的有机物中，90%以上在中层内被矿化，中层从真光层底部（~ 100米）延伸到1000米以上的深度。其中一些物质以十年或更小的尺度作为营养物质、微量元素和二氧化碳返回到海面，而剩余的有机物质则转移到深海内部并储存数千年。 尽管重要和广阔，中层领域是海洋中研究最少的区域之一，因此我们预测真光层、深海和海洋边缘之间二氧化碳和营养物交换的驱动过程的能力有限。拟议研究的长期目标是广泛了解影响海洋中层浮游生物和微浮游生物组成、多样性、密度和稳定性的基本生态原则。我们希望查明极地、温带和热带地区中层区结构和碳循环的差异/相似之处;第二，建立一个生态系统模型（未来的合作努力），提供上层-中层-深海区之间的机械联系。以东北太平洋中层区为空间重点的拟议研究的短期目标将：（a）有助于确定东温带和亚北极太平洋中层浮游生物和微浮游生物的组成和垂直结构;（B）将中层食物网的结构和多样性与上层生产力以及次表层氧浓度联系起来;（c）量化不同微浮游生物群从表层到中层的碳活性迁移总量;（d）量化评估“神秘食物网”。这将建立在温哥华岛西海岸和帕帕站（西亚北极太平洋）长期监测方案提供的研究机会的基础上。如果中层水域成为未来捕捞的目标，拟议的研究将对全球渔业很重要。广泛地说，它将用于合作开发北太平洋生物物理/渔业耦合模型。通过提供有关中层水食物网的新信息，该提案将为制定一项跨学科的多国举措奠定基础，以了解中层生态系统及其在海洋碳循环中的作用，并在公海开展基于生态系统的管理。

A significant challenge for marine ecologists is to be able to predict climate change impacts, including acidification, warming and oxygen decline, on marine, particularly deep-sea, pelagic ecosystems. Biological removal of carbon from the upper, euphotic zone and export to the deeper waters, called the biological pump, plays a variable but significant role in determining carbon dioxide exchange at the surface. Greater than 90% of the organic matter exported both passively and actively from the euphotic zone is remineralized within the mesopelagic layer, which extends from the bottom of the euphotic zone (~ 100 m) to depths greater than 1000 m. Some of this material is returned to the surface as nutrients, microelements and carbon dioxide on decadal scales or less, while the remaining organic material is transferred to the deep ocean interior and stored for millennia. Despite importance and vastness, the mesopelagic realm is among the least studied regions of the ocean and thus our ability to predict the processes driving exchange in carbon dioxide and nutrients between the euphotic zone, deep-ocean and ocean margins is limited. The long-term goal of proposed research is to develop a broad understanding of the fundamental ecological principles driving the composition, diversity, density and stability of the mesopelagic plankton and micronekton in the ocean. We would like to identify the diss-/similarities in the structure and carbon cycling of mesopelagic zones in polar, temperate and tropical regions; second, to build an ecosystem model (future collaborative effort) that provides mechanistic links between epipelagic-mesopelagic-bathypelagic realms. The short term goals of the proposed study with the spatial focus on the NE Pacific mesopelagic zone will (a) contribute to a characterization of the composition and vertical structure of mesopelagic plankton and micronekton in the eastern temperate and sub-Arctic Pacific; (b) link structure and diversity of mesopelagic food webs to overlaying productivity, as well as to subsurface oxygen concentrations; (c) quantify the total carbon active transport from surface layers into midwaters by different groups of micronekton; and (d) assess quantitatively the "cryptic food web". This will be built upon research opportunities provided by the long-standing monitoring programs off the west coast of Vancouver Island and at the Station Papa (western sub-Arctic Pacific). The proposed research will be important to global fisheries if midwater realm will become targeted for the future harvest. Broadly, it will be used in a collaborative effort to develop a coupled biophysical/fishery model of North Pacific. By providing novel information on midwater food webs, this proposal will lay foundation to the development of an interdisciplinary, multinational initiative to understand the mesopelagic ecosystem and its role in the marine carbon cycle as well to develop ecosystem-based management in the open ocean.