The Kimberley: some pieces of the puzzle

On the eastern edge of the Indian Ocean, downstream from the Indonesian Through-Flow, with some of the largest tides in the world and in the wet tropics; the Kimberley region has a myriad of factors that influence its ecology. The region has become the centre of Australia’s booming mineral, oil and gas industries; yet the functioning of its pelagic ecosystem is virtually unstudied. Satellite observations indicate massive blooms of coccolithophorids with their potential to significantly exacerbate ocean acidification. Sporadic observations suggest widespread blooms of Trichodesmium possibly representing the largest single input of new nitrogen into a nitrogen limited ecosystem. The pelagic primary production supports a diverse food web consisting of a range of zooplankton and fish species. The region has valuable aquaculture activities, fisheries and a large migratory community of marine birds and mammals. During a 2010 research voyage we examined many aspects of the marine ecology within this ecosystem. The research was focused on describing the benthic and pelagic communities, measuring the fluxes of nitrogen and carbon while seeking to understand the processes that determine the region’s primary production. Considerable emphasis was placed upon observing physical processes that inject nutrients into the euphotic zone to stimulate primary production or enhance nutrient cycling such as the tides, internal waves and terrestrial inputs. A suite of measurements were made to improve our ability to use remote sensing to observe and manage this remote environment. An overview of the cruise, its objectives and some examples of the results will be presented. These will be placed in the context of regional ecology and the challenges for Australia in terms of managing this relatively pristine ecosystem.