Publication Date: 10 October, 2014
Life in the Changing Ocean
The 3rd World Conference on Marine Biodiversity will take place in Qingdao, China this October from 12 – 16 and is organised by the Institute of Oceanology, Chinese Academy of Sciences. Dr Tasman Crowe, UCD School of Biology and Environmental Science, who is part of the Scientific Committee for the conference will also co-convene and co-chair a session on the 13 October on ‘Linking Marine Biodiversity Science and Advice’. Dr Crowe will also present at the session on: Biological Traits Analysis as an indicator of ecosystem functioning based on biodiversity data (abstract below).
Dr Paul Brooks also will be presenting the key-note for a session on ’Effects of Multiple Stressors on Ecosystem Process, Functioning and Services’with a presentation entitled: Combined effects of multiple stressors: A field based response-surface experiment reveals variation in interactive effects across a range of concentrations and levels of organization (abstract below).
Full details of the conference are available here.
Biological Traits Analysis as an indicator of ecosystem functioning based on biodiversity data
Devin Lyons, Andrew Blight, Christos Arvanitidis, Eva Chatzinikolaou, Dannielle Green, Tamar Guy-Haim, Jonne Kotta, Agnese Marchini, David Paterson, Ana Queiros, Gil Rilov, Paul Somerfield and Tasman Crowe
Environmental policy and management are increasingly based on ecosystem services, which in turn depend on ecosystem functioning. Cost effective and widely applicable indicators of ecosystem functioning and services therefore need to be developed and adopted. Changes in biodiversity are known to be linked to changes in functioning and functional trait-based approaches such as Biological Traits Analysis (BTA) are regarded as being potentially suitable as a basis for indicators of ecosystem functioning and services. However, although BTA has been shown to indicate changes in predicted functional capacity associated with particular human activities and pressures, links between changes in trait profiles and changes in functioning have not yet been demonstrated empirically.
Here, we analysed experimental and observational datasets combining detailed assessments of biodiversity with measurements of a number of ecosystem properties and processes to (a) develop a framework for using BTA as an indicator of functioning and (b) test its effectiveness in predicting functioning in a number of intertidal and subtidal sedimentary ecosystems. Initial analyses have focussed on a dataset derived from experimental manipulation of densities of invasive oysters Crassostrea gigas in intertidal sedimentary plots. The biota in the plots have been characterised in terms of maximum body size, feeding mode, mobility, habit, growth form, longevity, food type, sociability, bioturbation and environmental position. Subsets of these traits have been effective in predicting pools of ammonium, silicate and organic matter and fluxes of carbon dioxide. Tests of the applicability of the framework in other systems are ongoing at the time of writing, but results will be available for presentation at the conference.
Combined effects of multiple stressors: a field based response-surface experiment reveals variation in interactive effects across a range of concentrations and levels of organization
Paul R. Brooks, Mark A. Browne, Lisandro Benedetti-Cecchi, Devin A. Lyons and Tasman P. Crowe
Ecosystems are affected by multiple anthropogenic stressors from a wide range of sources. This is problematic because multiple stressors can modify each others’ influences in ways that may vary depending on their respective intensities/concentrations. Such effects are poorly understood because they require large complex experiments that have hitherto been difficult to run in the field. A novel system has been developed to deliver controlled doses of multiple stressors to simulate complex regimes of stress in experimental plots at a marina near Dublin, Ireland.
Here we tested whether copper and chlorpyrifos (a biocide) act independently or interactively on marine fouling communities and how their combined effects on organisms and ecosystem functions vary depending on their respective concentrations.
Using a response-surface design, five concentrations of each stressor were manipulated in factorial combinations for a total of 25 treatments (n=4). After six weeks, chemical uptake and impacts at several levels of biological organisation were measured, from sub-cellular (cellular viability) to ecosystem (respiration and clearance rates).
Stressor combinations produced interactive effects that would not have been revealed without using the response-surface approach. For example, when copper and biocide were combined they interacted antagonistically, negating each others’ effects such that at intermediate concentrations of biocide and higher concentrations of copper, the cellular viability of mussels was no different from the control plots. Concentrations of copper in the tissues of mussels were affected by a synergistic interaction with biocide: mussels exposed to low concentrations of biocide and high concentrations of copper accumulated twice as much copper as with the highest concentration of copper alone.
Effects among response variables varied and ecosystem-level responses were not always predictable on the basis of sub-cellular responses. Although cellular viability was an effective predictor of ecosystem-level responses to individual stressors, its responses to multiple stressors did not match responses in rates of clearance and respiration by the assemblage.
Our results highlight that non-additive effects of multiple stressors may be more complex and more common than previously thought. This research also reveals that multiple stressors can reduce the ability of established biomarkers of pollution to indicate impacts at higher levels of organisation.