Ms Rachel Downey

MSc Geography
PhD Student

Antarctic marine biogeographer and taxonomist of Southern Ocean sponges.

Research focus on

  • The diversity and distribution of sponges in polar environments using taxonomic, ecological and genetic approaches.
  • The use of sponges and other sessile organisms in assessing uptake and storage of carbon in polar oceans.
  • Sub-ice shelf and post ice-shelf collapse sponge communities in the Southern Ocean

Research interests

Thesis title

Southern Ocean sponge phylogeography: a tool for understanding connectivity and climate change impacts in the Antarctic and sub-

Thesis description

The Southern Ocean (SO) covers ~35 million km2 and its circulation is dominated by the largest ocean current in the world, the Antarctic Circumpolar Current (ACC), which flows clockwise around Antarctica, and acts as a barrier to warmer ocean waters in the north. In the recent past, Antarctica has undergone major environmental change, and currently the region is undergoing unprecedented changes in sea ice, continued ice-shelf collapse, increased glacier melt, and ocean warming, which are expected to intensify in the future.

Understanding how marine benthic organisms have responded to changes in the recent past, through adaptation and migration, gives us an indication of how they might respond to future changes. During the last glaciation, temperatures and sea levels dropped, ice-sheets grew extensively across the Antarctic shelf, and sea ice coverage, duration, and ice-scouring increased. Molecular studies have revealed that many benthic Antarctic organisms survived in refugia, either in deep water, localised shallow areas that were not heavily impacted by ice-scouring, or further north in the sub-Antarctic.

This study will look at the response of sponges (Porifera) in the SO and adjacent regions, combining methods in genetics and taxonomy, to understand the diversity of sponges, connectivity of sponge populations and their associated infauna in the SO and adjacent regions, and how sponge communities have responded to past environmental change. Sponges are an excellent model taxon for this work because they are diverse and abundant, inhabit a wide range of environments, form a major part of marine food webs, their morphological plasticity provides habitat for numerous organisms, and they have diverse reproductive and life strategies.

Goodwin, C., Berman, J., Downey, R.V. & Hendry, K. (2017). Carnivorous sponges (Porifera, Demospongiae, Poecilosclerida, Cladorhizidae) from the Drake Passage (Southern Ocean) with a description of eight new species and a review of the family Cladorhizidae in the Southern Ocean. Invertebrate Systematics.

Barnes, D.K.A., Sands, C.J., Hogg, O.T., Robinson, B.J.O., Downey, R.V., Smith, J.A. (2016). Biodiversity signature of the Last Glacial Maximum at South Georgia, Southern Ocean. Journal of Biogeography. DOI: 10.1111/jbi.12855

Morley, S.A., Berman, J., Barnes, D.K.A., de Juan Carbonell, C., Downey, R.V., Peck, L.S. (2016). Extreme Phenotypic Plasticity in Metabolic Physiology of Antarctic Demosponges. Frontiers in Ecology and Evolution: doi: 10.3389/fevo.2015.00157

Downey, R.V., Janussen, D. (2015). New insights into the abyssal sponge fauna of the Kurile–Kamchatka plain and trench region (Northwest Pacific). Deep-Sea Research II: Topical Studies in Oceanography 111, 34-43.

Saucède, T., Griffiths, H.J., Moreau, C.V.E., Jackson, J.A., Sands, C.J., Downey, R.V., Reed, A., Mackenzie, M., Geissler, P. & Linse, K. (2015). East Weddell Sea echinoids from the JR275 expedition. Zookeys, vol. 504, pp. 1-10. doi: 10.3897/zookeys.504.8860

Barnes, D.K.A., Downey, R.V. (2014). Bryozoa. In: De Broyer C., Koubbi P., Griffiths H.J., Raymond B., Udekem d’Acoz C. d’, et al. (eds.). Biogeographic Atlas of the Southern Ocean. Scientific Committee on Antarctic Research, Cambridge, pp. 195-199.

Janussen, D., Downey, R.V. (2014). Porifera. In: De Broyer C., Koubbi P., Griffiths H.J., Raymond B., Udekem d’Acoz C. d’, et al. (eds.). Biogeographic Atlas of the Southern Ocean. Scientific Committee on Antarctic Research, Cambridge, pp. 94-102.

Hillenbrand, C-D., Kuhn, G., Smith, J.A., Gohl, K., Graham, A.G.C., Larter, R.D., Klages, J.P., Downey, R.V., Moreton, S.G., Forwick, M. & Vaughan, D.G. (2013). Grounding-line retreat of the West Antarctic Ice Sheet from inner Pine Island Bay. Geology. doi: 10.1130/G33469.1

Downey, R.V., Griffiths, H.J., Linse, K., Janussen, D. (2012). Diversity and Distribution Patterns in High Southern Latitude Sponges. PLOS ONE 7(7):E41672. DOI: 10.1371/journal.pone.0041672

Sands, C.J., Griffiths, H.J., Downey, R.V., Barnes, D.K.A., Linse, K. & Martin-Ledo, R. (2012). Observations of ophiuroids from the west Antarctic sector of the Southern Ocean. Antarctic Science: doi: 10.107/s0954102012000612