High biodiversity on a deep-water reef in the eastern Fram Strait.

Kirstin S Meyer,Thomas Soltwedel,Melanie Bergmann,Philippe Archambault

doi:10.1371/journal.pone.0105424

Kirstin S Meyer, Thomas Soltwedel + Show 2 more

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https://doi.org/10.1371/journal.pone.0105424

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Abstract

We report on the distribution and abundance of megafauna on a deep-water rocky reef (1796–2373 m) in the Fram Strait, west of Svalbard. Biodiversity and population density are high, with a maximum average of 26.7±0.9 species m−2 and 418.1±49.6 individuals m−2 on the east side of the reef summit. These figures contrast with the surrounding abyssal plain fauna, with an average of only 18.1±1.4 species and 29.4±4.3 individuals m−2 (mean ± standard error). The east side of the reef summit, where the highest richness and density of fauna are found, faces into the predominant bottom current, which likely increases in speed to the summit and serves as a source of particulate food for the numerous suspension feeders present there. We conclude that the observed faunal distribution patterns could be the result of hydrodynamic patterns and food availability above and around the reef. To our knowledge, this study is the first to describe the distribution and diversity of benthic fauna on a rocky reef in deep water.

Highlights

The deep sea is generally characterized by soft sediments, with hard-bottom habitats representing anomalies, though hard-bottom habitats are often home to a variety of species and functional groups not found elsewhere [1]
The reef is located in the eastern Fram Strait, west of Svalbard at approximately 79u 069 N/04u 289 E, and it lies within the HAUSGARTEN oceanographic observatory [33]
Our results show that suspension feeders, including a wide array of sponges, dominate the community on a steep rocky reef in the deep sea

Summary

Introduction

The deep sea is generally characterized by soft sediments, with hard-bottom habitats representing anomalies, though hard-bottom habitats are often home to a variety of species and functional groups not found elsewhere [1]. A reef is here defined as a 3-dimensional, hardbottom structure which provides habitat for sessile organisms and fish. Rising over 500 m depth in just 800 m horizontal distance, the present deep-water reef features sheer, rocky faces covered by a wide variety of sponges, anemones, and soft corals. Research has centered on how habitat structure affects the distribution [2,3,4,5,6,7] and recruitment [8,9,10] of fish fauna on coral and rocky reefs, the impacts of fish predation on rocky reef communities [11,12], as well as the implications of marine reserves and artificial reefs [13,14] for conservation and fisheries management. The present study is the first to describe the distribution and abundance of fauna on a rocky reef in the deep sea

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