Data_Sheet_1_Life in the Fast Lane: Modeling the Fate of Glass Sponge Larvae in the Gulf Stream.docx

Effective conservation management of deep-sea sponges, including design of appropriate marine protected areas, requires an understanding of the connectivity between populations throughout a species’ distribution. We provide the first consideration of larval connectivity among deep-sea sponge populations along the southeastern coast of North America, illustrate the influence of the Gulf Stream on dispersal, and complement published distribution models by evaluating colonization potential. Connectivity among known populations of the hexactinellid sponge Vazella pourtalesii was simulated using a 3-D biophysical dispersal model throughout its distribution from Florida, United States to Nova Scotia, Canada. We found no exchange with an estimated pelagic larval duration of 2 weeks between populations north and south of Cape Hatteras, North Carolina at surface, mid-water and seabed release depths, irrespective of month of release or application of a horizontal diffusion constant specific to cross-Gulf Stream diffusivity. The population north of Cape Hatteras and south of Cape Cod was isolated. There was some evidence that Gulf Stream eddies formed near Cape Hatteras could travel to the northwest, connecting the populations in the two sub-regions, however that would require a much longer pelagic duration than what is currently known. More likely almost all larval settlement will be in the immediate area of the adults. At sub-regional scales, connectivity was found from the Strait of Florida through to the Blake Plateau, southeastern United States, with the latter area showing potential for recruitment from more than one source population. The influence of the Charleston Bump, a shallow feature rising from the Blake Plateau, was substantial. Particles seeded just north of the Bump were transported greater distances than those seeded to the south, some of which were caught in an associated gyre, promoting retention at the seabed. To the north on the Scotian Shelf, despite weaker currents and greater distances between known occurrences, unidirectional transport was detected from Emerald Basin to the Northeast Channel between Georges and Browns Banks. These major conclusions remained consistent through simulations run with different averaging periods for the currents (decades to daily) and using two ocean model products (BNAM and GLORYS12V1).

有效管理深海海绵的 conservation，包括设计适宜的海洋保护区，需对物种分布范围内各种群之间的连通性有所理解。本研究首次探讨了北美东南沿海深海海绵种群中幼虫的连通性，阐述了墨西哥湾流对扩散的影响，并通过评估殖民潜力，补充了已发表的分布模型。利用三维生物物理扩散模型，对六放海绵属（Vazella pourtalesii）已知种群在从美国佛罗里达州至加拿大新斯科舍省的分布范围内进行了连通性模拟。研究发现，在北卡罗来纳州哈特拉斯角以北和以南的种群之间，无论释放月份或应用横跨墨西哥湾流的扩散常数，在表层、中层和水底释放深度处均未观察到交换，估计的浮游幼虫持续时间为两周。哈特拉斯角以北和科德岛以南的种群孤立存在。有证据表明，哈特拉斯角附近的墨西哥湾流涡流可能向西北方向移动，连接两个子区域的种群，但这将需要一个比目前所知的更长的浮游持续期。更有可能的是，几乎所有幼虫的定居都将发生在成体的直接区域。在次区域尺度上，从佛罗里达海峡至美国东南部的布莱克平原之间发现了连通性，后者区域显示出从多个来源种群招募的潜力。查尔斯顿隆起（一个从布莱克平原升起的浅层特征）的影响是显著的。在隆起以北播种的颗粒比向南播种的移动距离更远，其中一些被相关的涡流捕获，促进了海底的保留。在斯科特浅滩北部，尽管已知发生地点之间的水流较弱且距离更远，但检测到从翡翠盆地至乔治斯和布朗斯银行的东北通道的单向传输。这些主要结论在不同的平均周期（数十年至每日）的电流模拟以及使用两个海洋模型产品（BNAM 和 GLORYS12V1）的模拟中均保持一致。