Particle Transformations in the "Regeneration Zone": The Biology and Chemistry of Mesopelagic Aggregates

在海洋表层水中合成的大部分有机物质被返回到500米以上的无机物中，即“再生区”。海洋学家将这些化学变化主要归因于生物。然而，令人惊讶的是，人们对真光带以下的再矿化生物学知之甚少：负责的生物体是否主要是后生动物或微生物，以及它们是否发生在将物质输送到深处的较大颗粒上。Pilskaln博士和Silver博士将在蒙特利湾进行一项为期两年的研究，研究微生物和浮游动物在1 mm颗粒再矿化中的作用。蒙特利湾是一个可到达的相对较深的水域。利用现场观察和实验室测量相结合的方法，她将研究丰富的海洋雪粒和可以作为此类研究的模型系统的非常大的聚集体(m大小)。她计划(1)测量团聚体的大小和丰度，(2)确定它们的化学性质和相关的生物群落，(3)测量群落对颗粒的再生相关活动，以及(4)将与颗粒相关的再矿化率与该地区沉积物捕捉器测量的速率进行比较。对于这些测量，她将使用带有ROV和海洋雪上相机的实地调查，从ROV操作的各种采样设备，以及在船上和实验室培养的自然样品的一系列实验。在第二年，皮尔斯卡恩博士横切了加州的洋流，以了解那些被认为是蒙特利湾的再生中心的非常大的聚集体是否出现在更远的离岸海域。这些结果将增加对中水再矿化生物学的理解，以及颗粒在这一过程中所起的作用。

Most organic matter synthesized in surface waters of the sea is returned to inorganic constituents within the upper 500 m, or "regeneration zone." Oceanographers attribute these chemical transformations mostly to living organisms. Yet surprisingly little is known about the biology of remineralization below the euphotic zone: whether the responsible organisms are dominantly metazoan or microbial and whether or not they occur on the larger particles that deliver material to depth. Dr. Pilskaln, together with Dr. Silver will conduct a 2-year study in Monterey Bay, and accessible, comparatively deep water site, to study the role of both microbes and zooplankton in the remineralization of particles 1mm. Using a combination of in situ observations and laboratory measurements, she will study both the abundant marine snow particles and very large aggregates (m size) that can serve as model systems for such studies. She plans to (1) measure the size and abundance of the aggregates, (2) determine their chemical properties and associated living communities, (3) measure regeneration-related activities of the communities on the particles, and (4) compare and particle-related remineralization rates to those measured by sediment traps in the area. For these measurements, she will use field surveys with a Romotely Operated Vehicle (ROV) and a Marine Snow Camera, a variety of sampling devices operated from the ROV, and a series of experiments on natural samples incubated on shipboard and in the laboratory. In year 2, Dr. Pilskaln transects the California Current to learn whether the very large aggregates, which are hypothesized to be regeneration centers to Monterey Bay, occur in significant numbers further offshore. These results will increase the understanding of the biology of midwater remineralization and the role that particles can play in the process.