Effects of warming on recruitment and marine benthic community development in Antarctica

One of the most important current questions in science, and one of the issues of most concern to society and decision makers is how life and biodiversity on Earth will respond to climate change (Millennium Ecosystem Assessment, UN convention on Biological Diversity). Scientists and policymakers recognise that ecosystem level predictions of responses to change are particularly important. These types of predictions are a fundamental requirement for the future management of biodiversity, agricultural and fisheries concerns.
However, evaluations of likely responses to change at the ecosystem level are rare and fraught with difficulty. To date predictions of responses to change in animals have been primarily at the species level and based around 2 approaches. The first uses current species ranges (climate envelope models) and then predicts future ranges by assessing where similar conditions are likely to be from climate models. The second approach evaluates an organism's physiological capacity to cope with experimentally altered conditions in the laboratory. Both approaches have significant problems when scaling up beyond the species. Climate envelope approaches suffer from a lack of knowledge of adaptation rates and genetic and functional tolerance differences within and between populations. They also have problems because site-specific conditions often differ significantly from the average environments that most climate envelope models use. Physiological tolerance approaches are limited because they predominantly evaluate small numbers of species and because experimental rates of change are usually much faster than natural change. Both approaches suffer from a lack of characterisation of how ecological factors such as competition and predation will change. They also both need an increase of scale to be more relevant.
A key requirement is to improve understanding of assemblage or community level processes and responses. In the terrestrial environment, and for microbial communities this problem has been extensively addressed, mainly via field manipulation of conditions and through the use of laboratory based systems such as the ecotron. In marine studies, field-based approaches to investigating both organism responses and community level effects of warming are scarce, especially for marine benthic animals. Here we are proposing to use novel technology, developed over the last 3 years at the British Antarctic Survey, to overcome many of these problems and provide data not previously obtainable. We plan to deploy heated settlement panels alongside unheated controls at 3 sites near the Rothera research station in the Antarctic. At each site two treatments will have heated panels set at a constant 1C and 2C above ambient (to match roughly 50 and 100 year oceanic warming predictions). A third treatment will have seasonal heating to match 100 year predictions for local conditions. The approach of using heated panels in marine environments has not been previously used because of the technical difficulty of maintaining elevated temperatures in the sea. Working on slow-growing small encrusting species on the seabed allows this to be done where it is not possible elsewhere.

Beneficiaries of this research will vary with timescales. In the short-term the benefits will be directly to the science community, to conservationists and to policy makers concerned with developing marine protected areas in Antarctica. In the medium-term an improved mechanistic understanding of the effects of warming on nearshore benthic community development will be of value to similar groups outside Antarctica.
There are major concerns with how climate change will impact biodiversity and how this will affect ecosystems, and upstream ecosystem services. There is consensus that markedly improved models of the impacts of change are required and that these need to be at the ecosystem level. This requires improved understanding at the community level, especially for marine ectotherm species. This project will provide data important for the improvement of our ability to take current models of responses to change in marine environments and scale them up to ecosystem levels of understanding. Benefits will include:
To the public: there will be benefits in the short-term, because impacts of climate change are of strong public and media interest. We plan to meet this requirement through press releases via the BAS and NERC publicity offices. We will also make the information available on the BAS website and through interviews with TV, radio and press outlets, public lectures, school talks and a lecture series (the PI alone has given over 100 media interviews in the last 10 years).
To conservation Bodies: There will be benefits in two main areas for conservation bodies. Firstly there will be benefits from identifying the relative performances of the groups of organisms studied here under field warming conditions. There is currently little information on effects of warming on these characters for many of the early benthic colonising marine invertebrate groups in the field. Identifying the least resilient groups in our study will provide conservationists with a focus for later studies in temperate regions. Secondly understanding effects of warming at the assemblage/community level in marine systems will be a step towards a more sophisticated level of modelling of predictions of impact of change on marine biodiversity. This should lead to a generally improved level of information available for marine conservation.
To policymakers and environment agencies: Policymakers need to maintain healthy coastal environments for many societal requirements, including tourism, effluent breakdown and exploitation. Nearshore seabed communities play key roles in maintaining the health of these systems. Our data will provide novel information that will improve our abilities to predict the health of nearshore ecosystems in the coming decades, specifically in Antarctica, but with relevance elsewhere, because of the ubiquity of the major groups studied.
There are also potential economic consequences of this research. It is aimed at understanding how encrusting (biofouling) communities respond to a warmed environment. The dynamics and potential response to change of such communities are poorly understood at high latitude, yet the opening of an Arctic seaway is seen as a major likely development and currently marine antifouling is a multibillion dollar industry.