Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, USA.
Sci Rep. 2023 Apr 25;13(1):6739. doi: 10.1038/s41598-023-33854-0.
Pelagic-benthic coupling describes the connection between surface-water production and seafloor habitats via energy, nutrient and mass exchange. Massive ice loss and warming in the poorly studied Arctic Chukchi Borderland are hypothesized to affect this coupling. The strength of pelagic-benthic coupling was compared between 2 years varying in climate settings, 2005 and 2016, based on δC and δN stable isotopes of food-web end-members and pelagic and deep-sea benthic consumers. Considerably higher isotopic niche overlap and generally shorter isotopic distance were found between pelagic and benthic food web components in 2005 than in 2016, suggesting weaker coupling in the latter, low-ice year. δN values indicated more refractory food consumed by benthos in 2016 and fresher food reaching the seafloor in 2005. Higher δC values of zooplankton indirectly suggested a higher contribution of ice algae in 2005 than 2016. The difference in pelagic-benthic coupling between these years is consistent with higher energy retention within the pelagic system, perhaps due to strong stratification in the Amerasian Basin in the recent decade. Weaker coupling to the benthos can be expected to continue with ice loss in the study area, perhaps reducing benthic biomass and remineralization capacity; monitoring of the area is needed to confirm this prediction.
远洋-底栖耦合描述了通过能量、营养和物质交换，将地表水的产生与海底生境联系起来的过程。人们假设，在北极楚科奇边缘地区，冰量的大量流失和变暖会影响这种耦合。本研究基于食物网终末成员以及远洋和深海底栖消费者的 δC 和 δN 稳定同位素，比较了 2005 年和 2016 年这两个气候背景不同年份之间的远洋-底栖耦合强度。与 2016 年相比，2005 年远洋和底栖食物网组分之间的同位素生态位重叠明显更高，同位素距离通常更短，这表明后者在低冰年的耦合较弱。δN 值表明，2016 年底栖生物消耗的食物更难分解，而 2005 年到达海底的食物更新鲜。浮游动物较高的 δC 值间接表明，2005 年冰藻的贡献高于 2016 年。这些年份之间的远洋-底栖耦合差异与远洋系统中能量保留增加一致，这可能是由于近十年来亚美大陆架的强烈分层作用。在研究区域，随着冰量的减少，预计与底栖生物的耦合会减弱，这可能会降低底栖生物量和再矿化能力；需要对该地区进行监测，以证实这一预测。
