The role of glass sponge reefs in nutrient cycling: inputs, outputs, and evidence of population changes through the millennia

在不列颠哥伦比亚省的浅水区，玻璃海绵形成了密集的珊瑚礁，覆盖了数百公里的海底。海绵为商业上重要的岩鱼提供了独特的栖息地，但它们在当地生物地球化学循环中的作用尚未被探索。珊瑚礁正在考虑免受拖网捕鱼和其他捕鱼作业的影响，但它们作为碳（食物）和硅（骨骼材料）来源的作用，对于附近其他生产力较低的栖息地来说，可能同样重要，如果不是更重要的话。在提议的工作中，将使用脂肪酸和稳定同位素分析沉积物圈层、岩心、水样和海绵样品来追踪珊瑚礁下游的海绵“碳特征”。这个特征将被用来追踪进入珊瑚礁的碳输入，以及这些碳被海绵处理后的命运。硅的吸收率在历史上一直低于现有方法的检测极限，随着时间的推移，将使用一种涉及染料PDMPO的新方法来标记针状体中的生长环。最后，这些珊瑚礁的坚固性和范围将通过综合海洋钻探计划在不列颠哥伦比亚省周围收集的沉积物岩心进行检查。结合本文提出的不同方法和新方法，将提供海绵珊瑚礁在碳和硅循环中所起作用的清晰图景，并将有助于决策者为未来的海洋保护区决策提供信息。

Glass sponges form dense reefs covering hundreds of kilometers of seafloor in the shallow waters of British Columbia. The sponges provide a unique habitat for commercially important rockfishes, but their role in local biogeochemical cycling has not yet been explored. The reefs are under consideration for protection from trawling and other fishing operations, but their role as sources of carbon (food) and silicon (skeletal material) for other less productive habitats nearby may be of equal if not greater importance. In the proposed work, a sponge "carbon signature" will be traced downstream of the reefs using fatty acid and stable isotope analyses from sediment traps, cores, water samples, and sponge samples. This signature will be used to trace carbon inputs into the reefs and the fate of that carbon once it is processed by the sponges. Rates of silicon uptake, which have historically been below detection limits of current methods, will be integrated over time using a novel method involving the dye PDMPO to mark growth rings in spicules. Finally, the robustness and extent of these reefs will be examined using sediment cores collected around British Columbia by the Integrated Ocean Drilling Program. Combining the different approaches and novel methods proposed here will provide a clear picture of the role sponge reefs play in carbon and silicon cycling and will help inform policymakers for decisions on future marine protected areas.