ABSTRACT: Filter-feeders play an important role in regulating nutrient availability in coastal systems, with important implications for phytoplankton community composition, primary production, and food web structure. The role of filter-feeding bivalves in the nitrogen and phosphorus cycles is relatively well established, but their impact on coastal silicon (Si) cycling remains poorly understood. To help reduce this uncertainty, we quantified rates of Si recycling and the size of various Si pools at an oyster (Crassostrea virginica) farm. We found that oysters drive rapid recycling of dissolved Si (DSi) to the water column, primarily by altering rates of sediment Si flux. Sediments beneath oyster aquaculture recycled DSi to the water column at more than twice the rate (2476.06 µmol DSi m^-2 h^-1) of nearby bare sediments (998.75 µmol DSi m^-2 h^-1). Oysters consume DSi at a low rate (-0.06 µmol DSi ind.^-1 h^-1), and, while we were unable to determine the fate of that Si, we hypothesize that at least some of it may be stored in the shell and tissue, which are both small Si pools (0.55 and 0.13% Si by mass respectively). Si held in oysters is removed from the system when oysters are harvested, but this removal is small compared to oyster-mediated enhancements in sediment Si recycling. In a broader context, coastal systems with larger oyster populations are likely to have a more rapid Si cycle, with more Si available to primary producers in the water column than those with no oysters.

中文翻译：

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牡蛎养殖放大沿海硅循环

摘要：滤食动物在调节沿海系统养分供应方面发挥着重要作用，对浮游植物群落组成、初级生产和食物网结构具有重要意义。滤食性双壳类动物在氮和磷循环中的作用相对较好，但它们对沿海硅 (Si) 循环的影响仍然知之甚少。为了帮助减少这种不确定性，我们量化了牡蛎（Crassostrea virginica）养殖场的硅回收率和各种硅池的大小。我们发现牡蛎主要通过改变沉积物 Si 通量的速率来推动溶解的 Si (DSi) 快速循环到水体中。牡蛎养殖下的沉积物将 DSi 以两倍多的速率 (2476.06 µmol DSi m ^-2h ^-1 ) 附近裸露沉积物 (998.75 µmol DSi m ^-2 h ^-1 )。牡蛎消耗 DSi 的速率很低（-0.06 µmol DSi ind. ^-1 h ^-1），虽然我们无法确定 Si 的命运，但我们假设至少其中一些可能储存在壳中，组织，它们都是小 Si 池（分别为 0.55% 和 0.13% Si，按质量计）。牡蛎中的硅在收获牡蛎时从系统中去除，但与牡蛎介导的沉积物硅回收增强相比，这种去除很小。在更广泛的背景下，拥有更多牡蛎种群的沿海系统可能具有更快的硅循环，与没有牡蛎的沿海系统相比，水体中初级生产者可以获得更多的硅。