Roy Virginie, Iken Katrin, Archambault Philippe
Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada.
School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America.
PLoS One. 2014 Jul 14;9(7):e100900. doi: 10.1371/journal.pone.0100900. eCollection 2014.
Environmental gradients and their influence on benthic community structure vary over different spatial scales; yet, few studies in the Arctic have attempted to study the influence of environmental gradients of differing spatial scales on megabenthic communities across continental-scales. The current project studied for the first time how megabenthic community structure is related to several environmental factors over 2000 km of the Canadian Arctic, from the Beaufort Sea to northern Baffin Bay. Faunal trawl samples were collected between 2007 and 2011 at 78 stations from 30 to 1000 m depth and patterns in biomass, density, richness, diversity, and taxonomic composition were examined in relation to indirect/spatial gradients (e.g., depth), direct gradients (e.g., bottom oceanographic variables), and resource gradients (e.g., food supply proxies). Six benthic community types were defined based on their biomass-based taxonomic composition. Their distribution was significantly, but moderately, associated with large-scale (100-1000 km) environmental gradients defined by depth, physical water properties (e.g., bottom salinity), and meso-scale (10-100 km) environmental gradients defined by substrate type (hard vs. soft) and sediment organic carbon content. We did not observe a strong decline of bulk biomass, density and richness with depth or a strong increase of those community characteristics with food supply proxies, contrary to our hypothesis. We discuss how local- to meso-scale environmental conditions, such as bottom current regimes and polynyas, sustain biomass-rich communities at specific locations in oligotrophic and in deep regions of the Canadian Arctic. This study demonstrates the value of considering the scales of variability of environmental gradients when interpreting their relevance in structuring of communities.
环境梯度及其对底栖生物群落结构的影响在不同空间尺度上有所不同；然而，北极地区很少有研究试图探讨不同空间尺度的环境梯度对大陆尺度上大型底栖生物群落的影响。当前项目首次研究了在加拿大北极地区2000多公里的范围内，从波弗特海到巴芬湾北部，大型底栖生物群落结构与多种环境因素之间的关系。在2007年至2011年期间，在78个站点采集了动物拖网样本，深度从30米到1000米，研究了生物量、密度、丰富度、多样性和分类组成模式与间接/空间梯度（如深度）、直接梯度（如底层海洋学变量）和资源梯度（如食物供应代理）之间的关系。根据基于生物量的分类组成定义了六种底栖生物群落类型。它们的分布与由深度、物理水属性（如底层盐度）定义的大尺度（100 - 1000公里）环境梯度以及由底物类型（硬底与软底）和沉积物有机碳含量定义的中尺度（10 - 100公里）环境梯度显著但适度相关。与我们的假设相反，我们没有观察到总体生物量、密度和丰富度随深度的强烈下降，也没有观察到这些群落特征随食物供应代理的强烈增加。我们讨论了局部到中尺度的环境条件，如底层水流状况和冰间湖，如何在加拿大北极地区的贫营养和深海区域的特定位置维持生物量丰富的群落。这项研究证明了在解释环境梯度在群落结构中的相关性时考虑其变化尺度的价值。
