Collaborative Research: Silica Cycling in the Central North Pacific Gyre: Role of Rhizosolenia Mats and Suspended Diatoms

9414372维拉里亚尔全球物质平衡考虑、垂直营养剖面和季节性营养循环数据都表明，大型副热带大洋中涡旋可能占全球海洋生物成因二氧化硅产量的大部分。尽管硅藻在这些地区的春季开花期间可以变得丰富，但现有证据表明，每年的二氧化硅产量大多在夏季和秋季。在营养稀少的北中太平洋可能尤其如此，由于持续的层化，那里的浮游植物生产没有很强的季节性循环。在北太平洋中部的表层水域中，硅酸的浓度是所有贫营养环流中最高的。目前尚不清楚，与其他大洋中部系统相比，硅酸的更大可用性是否会导致该地区的二氧化硅产量更高。据报告，该地区的硅质生物量绝大多数(90%)由厘米大小的垫子组成，传统的水瓶采样器无法有效采样，通常由潜水员采集。这导致了一种独特的情况，即该地区的二氧化硅循环可能在全球范围内具有重大意义，可能由大量稀有销售主导，而使用传统采样方法的调查基本上看不到这些销售。该项目将是对北太平洋中部营养不良的生物成因二氧化硅的生产和溶解的第一次研究。我们的研究将结合使用水瓶采样器的传统水柱采样和潜水员制作的垫子收集，以比较这些大垫子和悬浮硅藻在该地区表层水域生物成因二氧化硅循环中的相对作用。这项研究将有两个主要目标：(1)评估中北部太平洋环流区二氧化硅产量的大小，以及(2)评估夏威夷外两个航次的根霉的相对贡献。

9414372 Villareal Global mass-balance consideration, vertical nutrient profiles, and seasonal nutrient cycle data all indicate that the large subtropical mid-ocean gyres may account for the majority of the global oceanic production of biogenic silica. Although diatoms can become abundant during spring blooms in these regions, the available evidence suggests that most of the annual silica production in summer and autumn. This may be especially true in the oligotrophic North Central Pacific which does not have a strong seasonal cycle of phytoplankton production due to Persistent stratification. The surface waters of the Central North Pacific contain the highest concentrations of silicic acid of any oligotrophic gyre. It is unknown whether this greater availability of silicic acid results in higher rates of silica production in this region compared to other mid ocean systems. Siliceous biomass in this region has been reported to be overwhelmingly dominated (90%) by centimeter- sized mats are not effectively sampled by traditional water bottle samplers and are typically collected by divers. This give rise to a unique situation where silica cycling in this region, which is likely to be significant in global terms, may be dominated by large rare sells that would be essentially invisible to investigations which employ traditional sampling methods. This project will be the first study of the production and dissolution of biogenic silica in the oligotrophic Central North Pacific Ocean. Our study will combine traditional water column sampling using water-bottle samplers with collections of mats made by divers to compare the relative roles of these large mats and suspended diatioms in the cycling of biogenic silica in the surface waters of this region. This study will have two major objectives: (1) to evaluate of the magnitude of silica production in the North Central Pacific Gyre, and (2) to assess the relative contribution mats of Rhizosolen ia two cruises out of Hawaii.