Vegetated coastal marine ecosystems are projected to expand northwards in the Arctic due to climate change, but the mechanisms for this expansion are complex and nuanced. Macroalgal biomass in the littoral areas of Svalbard has been increasing, but data at the glacier fronts are very scarce. In this study, we use hydroacoustics and video validation from an unmanned surface vehicle to survey macroalgal bed distribution along the coast of a High Arctic fjord (Billefjorden, Svalbard), including river bays and land- and sea- terminating glacier fronts, as well as oceanographic measurements to indicate physical drivers of macroalgal settlement. We found high variation of macroalgal coverage along the fjord coastline, with virtually no macroalgae in the river bays but abundant coverage in areas with little terrestrial runoff. Furthermore, the presence of kelp was found at the land-terminating glacier front which has recently retreated from the sea, which suggests the potential for rapid macroalgal establishment in newly available substrate following glacial retreat. These findings suggest large ecological implications throughout the Arctic, in which macroalgal expansion may lead to significant changes in the underwater coastal landscape and ecosystem. This study shows that the use of remote autonomous vehicles and hydroacoustic mapping with video validation has a high potential for sustainable and efficient ecological monitoring.

中文翻译：

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声学测绘揭示了高北极冰川前缘退缩后的大型藻类沉降


由于气候变化，预计北极沿海植被海洋生态系统将向北扩张，但这种扩张的机制复杂而微妙。斯瓦尔巴群岛沿岸地区的巨藻生物量一直在增加，但冰川前沿的数据非常稀少。在这项研究中，我们利用无人地面车辆的水声学和视频验证来调查高北极峡湾（比勒峡湾、斯瓦尔巴群岛）沿岸的大型藻床分布，包括河湾和陆地和海洋终止的冰川前缘，以及海洋学测量表明大型藻类沉降的物理驱动因素。我们发现，沿着峡湾海岸线，大型藻类的覆盖范围存在很大差异，河湾中几乎没有大型藻类，但在陆地径流很少的地区，大型藻类的覆盖范围却很丰富。此外，在最近从海洋退缩的陆地终止冰川前沿发现了海藻的存在，这表明在冰川退缩后，大型藻类在新的可用基质中快速建立的潜力。这些发现表明整个北极地区具有巨大的生态影响，其中大型藻类的扩张可能会导致水下沿海景观和生态系统的重大变化。这项研究表明，使用远程自动驾驶车辆和带有视频验证的水声测绘具有可持续和高效的生态监测的巨大潜力。