PhD Study : Impacts of predator loss on coastal sediment macrobenthos under present and future climate scenarios

Summary

Background

Coastal sediments account for less than 5 % of global sea floor area but are responsible for approximately 50 % of sea floor carbon cycling in the oceans (Middelburg et al., 1997). Coastal regions experience multiple anthropogenic stressors linked to fisheries, nutrient enrichment and climate change leading to species loss and changes in ecosystem functioning. At the sea floor, faunal species loss disproportionately affects larger predatory animals that directly control the structure of animal communities within marine sediments (Bruno and O’Connor, 2005). These megafauna can contribute up to 25 % of benthic community respiration (Piepenburg et al., 1995) and their activity has cascading impacts upon the smaller animals (macrofauna) and microorganisms at the seafloor (e.g. Hudson and Wigham, 2003; Jeffreys et al., 2009). Accurately predicting global-scale impacts of marine species loss requires an understanding of how species loss will affect faunal community structure and fundamental ecosystem processes both under present and predicted future climate warming scenarios.

Aims

In 2015, mesocosm experiments were conducted to investigate how presence / absence of a model predator (the shore crab Carcinus maenas) affected sediment community structure and ecosystem functioning under both present climate conditions and a future warming scenario (ambient + 2 oC). Initial results from this work has revealed highly significant interactions between predator presence and climate regime upon microbial activity within the sediment. The aim of this project is to investigate the effects of predator loss upon the structure of the macrobenthic faunal community under both present and future climate regimes.

Methods

Working with formalin fixed samples collected from a large mesocosm experiment, the student will enumerate and identify the macrobenthic invertebrates at different depth fractions within the sediment (0-2, 2-5, 5-10 cm) (e.g. Hunter et al., 2012; 2013). The student will develop an understanding of invertebrate taxonomy, a skill that is highly valued within environmental consultancies.

The student will use a range of univariate and multivariate statistical tools to investigate changes in the macrobenthic community structure between predator (presence/absence) and warming (ambient/ambient + 2oC) treatments.

References

Bruno and O’Connor 2005, Ecol Lett. 8, 1048-1056

Hudson and Wigham, 2003, J Mar Biol Assoc UK. 83, 463-464

Hunter et al., 2012, Biogeosci. 9. 993-1006.

Hunter et al., 2013, Biogeosci. 10, 67-80

Jeffreys et al., 2009, Deep Sea Res Pt I. 56, 1816- 1833

Middelburg et al., 1997, Deep Sea Res Pt I. 44, 327-344

Piepenburg et al., 1995, Mar Ecol Prog Ser. 118, 199-214

Essential criteria

Applicants should hold, or expect to obtain, a First or Upper Second Class Honours Degree in a subject relevant to the proposed area of study.

We may also consider applications from those who hold equivalent qualifications, for example, a Lower Second Class Honours Degree plus a Master’s Degree with Distinction.

In exceptional circumstances, the University may consider a portfolio of evidence from applicants who have appropriate professional experience which is equivalent to the learning outcomes of an Honours degree in lieu of academic qualifications.

Desirable Criteria

If the University receives a large number of applicants for the project, the following desirable criteria may be applied to shortlist applicants for interview.

• First Class Honours (1st) Degree
• Practice-based research experience and/or dissemination
• Experience using research methods or other approaches relevant to the subject domain
• Work experience relevant to the proposed project
• Experience of presentation of research findings

Funding and eligibility