Biodiversity of macrobenthic Mollusca in the deep Atlantic, with special reference to the Southern Ocean

Katrin Linse (BAS), Dr Phillip Fenberg, Huw J Griffiths (BAS)

The Latitudinal Species Diversity Gradient with a poleward decline is a well-established diversity pattern based on species occurrence records [Ref 1]. However, this pattern has not been tested with directly comparable assemblage sampling from the Southern Ocean (SO) across the equator to the North Atlantic. The SO is said to be the cradle of the global deep-sea fauna using thermohaline circulation to move northwards. Future climate change is predicted to warm the SO seafloor and impact deep-sea species [Ref 2]. Mollusca are one of the better-known taxa in deep sea biodiversity and a suitable taxon to study the influence of environmental factors on current biodiversity, community structure and biogeographic distribution [Ref 1, 3] and predict their future [Ref 2]. A comprehensive, comparable, and pan-Atlantic collection of macrobenthic Mollusca gathered by epibenthic sledges enables the application of a quantitative and multiproxy approach to assess community structure, to predict and model its future changes, as well as detailed ecological and evolutionary studies at the population level.

Quantitative assessments of deep-sea molluscan diversity from the Weddell Sea to Iceland are timely as the data will be relevant for Biological Diversity of Areas Beyond National Jurisdiction monitoring (


The project is studying diversity patterns of deep-sea, macrobenthic molluscan communities and their environmental drivers using existing pan-Atlantic samples collected by 201 EBS deployments in bathyal, abyssal and hadal depth from Iceland to the southern Weddell Sea. A more regional emphasis is on the community structure of macrobenthic Mollusca in the Southern Ocean Weddell Gyre region, which is experiencing changes in temperature and ice cover caused by climate change.

The project identifies recent EBS-collected Bivalvia, Gastropoda and Scaphopoda from the Weddell Gyre region to morphospecies level, to examine biodiversity, assemblage and functional trait structure.

The project establishes how diversity structures are influenced by environmental factors, such as depth, sediment, productivity, oceanographic conditions and/or length of ice-cover, taken from in-situ data and environmental databases (e.g. BioOracle).

Selected widely distributed taxa (morphospecies or genera) are used for morphometric and molecular genetic studies on their phylogeographic history, potentially influenced by the Weddell Gyre outflow into the Atlantic. Future distributions of these morphospecies will be modelled under different climate change scenarios.

This project gives a robust assessment of how biodiversity and community structures will react to changing marine deep-sea and polar environments [Ref 2] and tests hypotheses of deep-sea diversity [Ref 1].

British Antarctic Survey

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the British Antarctic Survey, Cambridge. Specific training will include:


·         Competence with univariate and multivariate data analysis techniques

·         ArcGIS package

·         Identification of macrobenthic Mollusca

·         SEM and micro-CT application

·         Molecular genetics from lab to analysis, e.g.  DNA extraction, bioinformatic and statistical software


The student will gain important research skills such as scientific writing and oral presentation by attending appropriate courses. If possible, travel to international scientific meetings to present project results will also be encouraged. There will be opportunities to visit international museums for comparative collection studies. While fieldwork is not required, if opportunities present, participation in expeditions will be considered. 

Essential Skills Required for the Project: 

1.         Morphological identification skills on recent or fossil marine invertebrates;

2.         Knowledge on ecology of marine environments

Eligibility & Funding Details: 

Please see for details.

Background Reading: 
  1. McClain CR, Schlacher, TA 2015. On some hypotheses of diversity of animal life at great depths on the seafloor. Marine Ecology doi 10.11111/maec.12288
  2. Griffiths HJ, Meijers AJS, Bracegirdle TJ (2017) More losers than winners in a century of future Southern Ocean seafloor warming. Nature climate change 7: 749-754
  3. Brandt A, Linse K, Ellingsen KE, Somerfield P (2016) Depth-related gradients in community structure and relatedness of bivalves and isopods in the Southern Ocean Progress in Oceanography 144: 25-38