Collaborative Research: Zooplankton feeding at the base of the particle maximum: Gatekeepers of the Vertical Flux?

一系列的观察表明，浮游动物充当了离开光区的物质的守门人。本研究将使用一套自主和系绳仪器，结合精细水样，研究浮游动物与其他颗粒的相互作用。SOLOPC（激光光学浮游生物计数器探空海洋观测仪）将是一个自主仪器，每小时提供浮游动物和其他颗粒的剖面。先前使用SOLPC进行的采样表明，在光带颗粒的产生和丰度以及它们的下沉和消耗有一个逐日循环，可能是在颗粒丰度最大值的底部观察到的浮游动物。SOLOPC探测颗粒，包括浮游动物和聚集体，并测量它们的等效球形直径，可用于计算颗粒大小光谱。然而，很难使用SOLOPC来区分颗粒类型，如桡足类、幼虫类和聚集体，特别是如果它们很小的话。该研究将包括在Monterey Bay进行的密集现场研究，并使用自适应采样，使用新的auv机载成像系统、舰载CTD和moness采样以及MBARI的ROV Ventana来观察solopc附近。研究人员将改变SOLOPC，使其相对于等共轴静止，并利用其积累的粒子数来计算通量谱。他们将结合通量和浓度谱来估计粒子沉降速度作为粒子直径的函数。通过分析被浮游动物网捕获的动物的肠道荧光和计算水样中粪便颗粒的分布，可以估计水柱中浮游动物的摄食情况。研究结果将增强对浮游动物作为颗粒垂直通量守门人的作用的理解，从而加强对生物泵的理解。这项研究还将为影响浮游动物行为和生态的因素提供新的见解。更广泛的影响将包括对一名研究生和一名博士后研究员的指导，不同机构之间的强有力合作，仪器开发和技术转让，成果的广泛传播，以及通过更好地了解碳循环的关键过程对社会的贡献。SIO的博士生和TAMU的博士后研究员将分别由Checkley和Jackson指导。合作机构包括SIO、TAMU、LUMCON、MBARI、BIO和巴黎第六大学。SOLOPC经过修改，可以测量通量和剖面，而REFLICS旨在供全球其他研究人员获取和使用。研究结果将在国内和国际会议上发表，并发表在同行评议的文献中。我们对浮游动物作为垂直通量守门人的作用的理解将有助于理解生物泵和碳循环。

A range of observations suggest that zooplankton act as gatekeepers for material leaving the euphotic zone. This study will investigate the interactions of zooplankton with other particles using a suite of autonomous and tethered instruments in conjunction with finescale water sampling. The SOLOPC (Sounding Oceanographic Observer with Laser Optical Plankton Counter) will be the autonomous instrument and provide hourly profiles of zooplankton and other particles. Previous sampling with the SOLPC indicated a diel cycle of production and abundance of particles in the euphotic zone and their sinking and consumption, presumably by zooplankton observed at the base of the particle abundance maximum. The SOLOPC senses particles, including zooplankton and aggregates, and measures their equivalent spherical diameters which can be used to compute particle size spectra. However, it is difficult to use the SOLOPC to distinguish among particle types, such as copepods, larvaceans, and aggregates, particularly if they are small. The research will include an intensive field study that will take place in Monterey Bay and use adaptive sampling to observe near SOLOPCs with a new, AUV-borne imaging system, ship-based CTD and MOCNESS sampling, and MBARI's ROV Ventana. The investigators will alter a SOLOPC to be stationary relative to an isopycnal and use the particle counts that it accumulates to calculate a flux spectrum. They will combine the flux and concentration spectra to estimate particle sinking velocities as a function of particle diameter. Zooplankton feeding in the water column will be estimated by analyzing the gut fluorescence of animals caught in zooplankton nets and by counting the distribution of fecal pellets in water samples. Results will enhance the understanding of the role of the zooplankton as gatekeepers in the vertical flux of particles and, hence, the biological pump. The study will also provide new insight into factors that affect zooplankton behavior and ecology.Broader impacts will include mentoring of a graduate student and a postdoctoral researcher, strong collaborations among diverse institutions, instrument development and technology transfer, broad dissemination of results, and contribution to society by better understanding of processes key to the carbon cycle. A PhD student at SIO and postdoctoral investigator at TAMU will be mentored by Checkley and Jackson, respectively. Collaborating institutions include SIO, TAMU, LUMCON, MBARI, BIO, and Université de Paris VI. The SOLOPC, modified to measure flux as a well as profile, and REFLICS are intended for acquisition and use by other researchers worldwide. Results will be presented at national and international meetings and published in the peer-reviewed literature. The understanding we gain of role of the zooplankton as gatekeepers of the vertical flux will contribute valuably to understanding of the biological pump and the carbon cycle.