Spatial scaling of deep-sea hydrothermal vent
food-webs in southern oceans
Background
The phenomenal faunal biomass of hydrothermal vents (“black smokers”) in the otherwise food-limited
deep sea is sustained by chemosynthetic production through bacterial symbiosis; these communities
represent some of the most extreme on our planet. Hydrothermal vents are frontier environments providing
new avenues of research into the origins of life on Earth, interactions between biodiversity and ecosystem
function, and have great potential for bio-prospecting of high temperature compounds for medicine and
industry (1). We are looking for an enterprising PhD student who will contribute to our ground-breaking
research in this context.
Vents occur as discrete habitats separated at different
spatial scales and by geological/environmental
barriers such that there is high species endemism
(commonly 70% of species). The geologic processes
that lead to vent formation and the fluids they emit
also result in the depositing of mineral wealth such
that these systems are under imminent pressure of
commercial extraction. Unlike for example fishing, a
small window remains to gain some understanding of
these unique systems pre-impact (2).
In 2009 the first exploration of vent sites was
conducted on the East Scotia Ridge (ESR) in the
Southern Ocean and Antarctic waters at depths
exceeding 2400m (3). Over 30 new genera and
species have been identified to date. This distinctive
fauna and the unique community structure it
represents suggest Antarctic vent ecosystems
represent a totally new vent biogeographic province.
In 2011 new vents were identified on the South West
Indian Ridge (SWIR) (4) which exhibits taxonomic
similarities and differences to the ESR and other
circum-Antarctic ridge sites. The spatially explicit
nature of vents allow us to explore the structure and
function of these systems at multiple ecological scales
from zonation within individual chimneys, through
chimney fields, sites, ridges and ocean basins.
Carwash chimney on the East Scotia Ridge
The Project
You will join a research group specializing in marine ecosystem dynamics to describe the structure and
function of the chemosynthetically driven vent communities and how they vary at spatial scales from metres
to 1000s km across the longitudinal gradient of circum-Antarctic ridges. Drawing from a valuable and
unique archive of samples collected by Newcastle University and the University of Southampton, you will
use carbon, nitrogen and sulphur stable isotope signatures to describe trophic ecology of fauna from the
ESR and the SWIR. Trophic understanding will be expanded using fatty acid biomarkers that provide
complementary information on food sources (5).
The successful candidate will have the opportunity to develop their interests to expand beyond the data
provided by bulk stable isotope and lipid techniques into other complementary analytical approaches for
example, compound-specific stable isotopes or ecological modeling that provide insight into system
structure and function and the trophodynamics of constituent fauna. Together these approaches will
1)
Describe How trophic functions vary within chimneys on the ESR
2)
Examine to what extent vent fluid chemistry determines this trophodynamics
3)
Assess how trophic roles of species or congenerics vary across ecological scales from among
sites on the ESR to the Indian Ocean circum-Antarctic ridges
4)
Develop function and trait based analyses that describe general structuring rules for vent systems
and describe functional equivalence (or lack thereof) among vet sites
The Supervisory Team
You will be supervised by Prof. Nick Polunin, Dr Ben Wigham and Dr Chris Sweeting (School of Marine
Science & Technology). Prof. Polunin leads the Marine Ecosystems and Governance research group at
Newcastle
(http://www.ncl.ac.uk/marine/research/science/ecology/index.htm)
and
is
a
marine
macroecologist who has pioneered stable isotope approaches to marine food webs, working extensively
with Dr Sweeting. Dr Wigham is a deep sea specialist with research interests in the physiology of deep sea
species, energy flow in deep sea and ridge systems and in reproductive and larval ecology and system
connectivity.
This work will be conducted within a wider collaboration of ongoing deep sea research including Dr Jon
Copley (University of Southampton; chemosynthetic ecosystems), Dr David Pond (SAMS, Oban; lipids) and
Dr Will Reid (Biology, Newcastle University; vent ecology, ecological modelling)
Informal enquires: Dr Chris Sweeting (christopher.sweeting@ncl.ac.uk, 0191 222 6658).
(1) Arico S, Salipin C (2005) Bioprospecting of Genetic Resources in the Deep Seabed: Scientific,
Legal and Policy Aspects. United Nations University
(http://www.ias.unu.edu/binaries2/DeepSeabed.pdf)
(2) International Seabed Authority (2011) Environmental management of deep-sea chemosynthetic
ecosystems: justification of and considerations for a spatially-based approach (Technical study;
no. 9), 79pp, ISBN 978-976-95268-9-1
(3) Rogers, A.D., et al. (2012) The discovery of new deep-sea hydrothermal vent communities in the
Southern Ocean and implications for biogeography, PloS Biology, 10(1) e1001234. doi:
10.1371/journal.pbio.1001234.
(4) Qiu J (2011) Indian Ocean vents challenge ridge theory 'Football fields' of vents among the largest
known.Nature News (20 December 2011) | doi:10.1038/nature.2011.9689
(5) Stevens CJ et al. (2008). Ontogenetic shifts in the trophic ecology of two alvinocaridid shrimp
species at hydrothermal vents on the Mariana Arc, western Pacific Ocean. Marine Ecology
Progress Series. 356: 225-237.