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

地球上的生命和生物多样性将如何应对气候变化是当前科学界最重要的问题之一，也是社会和决策者最关心的问题之一（千年生态系统评估，联合国生物多样性公约）。科学家和决策者认识到生态系统层面对变化反应的预测特别重要。这些类型的预测是未来管理生物多样性、农业和渔业问题的基本要求。然而，在生态系统层面对变化可能作出的反应进行评估是罕见的，而且充满了困难。迄今为止，对动物对变化的反应的预测主要是在物种水平上，基于两种方法。第一种方法使用当前的物种范围（气候包络模型），然后通过评估气候模型中可能出现类似情况的地方来预测未来的范围。第二种方法是评估生物体在实验室中应对实验改变条件的生理能力。当扩大到物种之外时，这两种方法都有明显的问题。气候包络法的缺点是缺乏对种群内部和种群之间的适应率以及遗传和功能耐受差异的了解。它们也有问题，因为特定地点的条件通常与大多数气候包络模型使用的平均环境有很大不同。生理耐受方法是有限的，因为它们主要评估少数物种，因为实验变化的速度通常比自然变化快得多。这两种方法都缺乏对竞争和捕食等生态因素将如何变化的描述。它们也都需要扩大规模，以提高相关性。一个关键的要求是提高对集合或社区级过程和响应的理解。在陆地环境中，对于微生物群落来说，这个问题已经得到了广泛的解决，主要是通过现场条件操纵和使用基于实验室的系统，如ecotron。在海洋研究中，以实地为基础的方法来调查生物对变暖的反应和群落水平的影响是很少的，特别是对海洋底栖动物。在这里，我们建议使用英国南极调查局过去3年来开发的新技术来克服许多这些问题，并提供以前无法获得的数据。我们计划在南极罗瑟拉研究站附近的3个地点部署加热定居板和不加热控制板。在每个地点，两种处理方法将加热面板设置在高于环境温度1℃和2℃的恒定温度（以匹配大约50年和100年的海洋变暖预测）。第三种治疗方法将采用季节性供暖，以匹配100年的当地条件预测。在海洋环境中使用加热板的方法以前从未使用过，因为在保持海洋高温方面存在技术困难。对海底生长缓慢的小型结壳物种进行研究，可以在其他地方无法做到的地方做到这一点。

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.