Scrosati Ricardo A, Ellrich Julius A
Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada.
Biologische Anstalt Helgoland, Shelf Sea System Ecology, Alfred Wegener Institute, Helgoland, Germany.
PeerJ. 2025 May 19;13:e19470. doi: 10.7717/peerj.19470. eCollection 2025.
Recruitment is a key demographic step for the persistence of populations, so understanding its drivers has traditionally been a relevant goal of ecology. On marine rocky shores, coastal oceanography is an important driver of the recruitment of intertidal invertebrates that reproduce through pelagic larvae by affecting larval transport and delivery. The intermittent upwelling hypothesis (IUH) posits that coastal pelagic larvae are driven offshore under intense upwelling or to depths under intense downwelling, while weak upwelling allows larvae to stay near the shore, thereby facilitating intertidal recruitment. The IUH thus predicts a unimodal relationship between Bakun's upwelling index (BUI) and intertidal recruitment. The IUH has been supported by studies that plotted simultaneously single average values of recruitment and BUI for various coastal locations that collectively span downwelling to upwelling conditions. Based on its theoretical foundations, the IUH should also hold for a target location analyzed over the years provided enough interannual variation in BUI. On the Atlantic Canadian coast in Nova Scotia, upwelling varies interannually depending on wind patterns. Therefore, for a location that is representative of the abiotic and biotic conditions on this coast (Western Head), we tested the IUH by measuring annual intertidal barnacle recruitment and BUI for the pelagic larval season of barnacles for a period of 10 years (2014-2024). On this coast, BUI averaged for the barnacle larval season varied among years from mild downwelling to clear upwelling. Generalized additive modelling revealed a unimodal relationship between intertidal barnacle recruitment and BUI, thereby supporting the IUH. These results add this western ocean boundary to the known list of coastal systems where upwelling may influence intertidal invertebrate recruitment.
补充是种群持续存在的关键人口统计学步骤，因此了解其驱动因素传统上一直是生态学的一个相关目标。在海洋岩石海岸，沿海海洋学是通过影响浮游幼虫的运输和输送来繁殖的潮间带无脊椎动物补充的重要驱动因素。间歇性上升流假说（IUH）认为，在强烈上升流期间，沿海浮游幼虫被驱赶到近海，或在强烈下沉流期间被驱赶到深处，而微弱的上升流使幼虫能够留在岸边，从而促进潮间带补充。因此，IUH预测了巴昆上升流指数（BUI）与潮间带补充之间的单峰关系。IUH得到了一些研究的支持，这些研究同时绘制了不同沿海地点（涵盖下沉流到上升流条件）的补充和BUI的单个平均值。基于其理论基础，如果BUI有足够的年际变化，IUH也应该适用于多年来分析的目标地点。在加拿大新斯科舍省的大西洋海岸，上升流因风型而异。因此，对于一个代表该海岸非生物和生物条件的地点（西头），我们通过测量10年（2014 - 2024年）期间藤壶浮游幼虫季节的年度潮间带藤壶补充和BUI来测试IUH。在这个海岸，藤壶幼虫季节的平均BUI在不同年份从轻度下沉流到明显上升流不等。广义相加模型揭示了潮间带藤壶补充与BUI之间的单峰关系，从而支持了IUH。这些结果将这个西部海洋边界添加到了已知的沿海系统列表中，在这些系统中上升流可能会影响潮间带无脊椎动物的补充。
