Classification and Mapping of Benthic Biotopes in Arctic and Sub-Arctic Norwegian Waters

Pål Buhl-Mortensen,Lilja Run Bjarnadóttir,Jon Albretsen,Genoveva Gonzalez-Mirelis,Lene Buhl-Mortensen,Rebecca E Ross,Margaret F J Dolan

doi:10.3389/fmars.2020.00271

Pål Buhl-Mortensen, Lilja Run Bjarnadóttir + Show 5 more

Open Access

https://doi.org/10.3389/fmars.2020.00271

Copy DOI

Abstract

In this paper we describe the species composition of biotopes occurring in a wide range of environments and present their geographic distribution based on results from quantitative analyses of video-records collected as part of the Norwegian seabed mapping programme MAREANO. We present results from an analysis of annotated video records at 757 stations from an area exceeding 100 000 km2 in the Barents Sea and Norwegian Sea. A two-way indicator species analyses (TWINSPAN) was used to identify sample groups and species assemblages for biotope classification. Environmental conditions were compared for the station groups identified at different similarity levels to detect environmental drivers behind each division and hence biotopes indicated by the analysis. In total 27 groups were identified as potential biotopes in the study area giving a geographic resolution suitable for management needs and subsequent predictive modelling. The faunal composition was mainly correlated with water masses (temperature and salinity). The most distinct biotope identified occurred on Spitsbergenbanken, a shallow area ( 600 m) NSDW, separating into two TWINSPAN groups. Further divisions of these groups reflected variations in sediment and terrain attributes. Ten biotopes were characterised by indicators species of vulnerable marine ecosystems (e.g. coral gardens, sea pen communities, and sponge aggregations). Knowledge about megafauna composition and biotopes is poor for deep-water benthic habitats in the Arctic region, and better classification of benthic biotopes will be valuable for management purposes such as design of monitoring program for documenting the effects of climate change on ecosystems.

Highlights

An increasing interest in deep-sea resources has brought about a growing number of offshore activities such as industrial fishing, mining, and oil and gas extraction (Ramirez Llodra et al, 2011)
Our results reflect that this region spans a biogeographic boundary where warmer Atlantic water and related communities meets with Arctic waters and the polar front. This region is highly susceptible to climate change with indications of an “Atlantification” of the Barents Sea region (Barton, 2018; Lind et al, 2018) suggesting that this boundary is likely to move northward due to decreasing southward extension of the sea ice
Twenty-seven biotopes were identified by applying TWINSPAN to quantitative species data obtained from analyses of seabed video records

Summary

Introduction

An increasing interest in deep-sea resources has brought about a growing number of offshore activities such as industrial fishing, mining, and oil and gas extraction (Ramirez Llodra et al, 2011). These activities cause a wide range of pressures on benthic ecosystems including animal removal, habitat destruction, sedimentation, pollution, etc. Area-based management is a tool to avoid negative impact on biological communities, habitats, and the environment. Area-based management, typically requires spatial ecological data, which is notably difficult to obtain (Steltzenmüller et al, 2013)

Objectives

Methods

Results

Discussion

Conclusion