Biodiversity, and the factors controlling it, for selected habitats in the Timor Sea region: Physical Oceanography of Karmt Shoals

Despite the major marine bioregions being broadly identified in north western Australia, there has been limited observation and documentation of the marine biodiversity present. The Oceanic Shoals bioregion, which includes numerous shelf edge reef systems, has been identified as a biodiversity hotspot for at least some major taxa, such as sponges, but past research has largely focused on the emergent reef systems at the western end of the bioregion. However, the most common reef types in the Oceanic Shoals bioregion do not reach the sea surface. These submerged reefs, which are biogenic in nature and rise out of deep water to between 10-50m below the sea surface, are very poorly understood and remain mostly to be explored and characterised. As mini seamounts, these reefs may well be areas of both biodiversity and biomass accumulation. The initial task for biodiversity surveys will be a census of submerged reefs to characterise the biodiversity, including its spatial pattern of habitats within reefs, then develop a regional model for habitat types and the location of any diversity hotspots. Integration with data on chemistry, oceanography and geology will be a feature of the Timor Sea study and will permit targeted multidisciplinary projects seeking to understand the processes that sustain the biota of the region. To this end, the distribution of shelf edge upwelling phenomena and natural hydrocarbon seeps, both potentially significant attributes of the bioregion, will be investigated and integrated with data on biodiversity patterns. This report summarises the deployment of 2 instrumented moorings in 50 and 100m water depth near Karmt Shoals in the Oceanic Shoals Bioregion of the Timor Sea. Moorings were set in January 2004, recovered and redeployed in April 2004, and finally recovered in December 2004.

尽管澳大利亚西北海域的主要海洋生物区（marine bioregions）已得到大致划定，但针对该区域现存海洋生物多样性的观测与记录工作仍较为匮乏。包含众多陆架边缘礁系统（shelf edge reef systems）的大洋浅滩生物区（Oceanic Shoals bioregion），已被认定为至少部分主要分类群（major taxa，如海绵）的生物多样性热点（biodiversity hotspot）区域，但既往研究大多聚焦于该生物区西端的出露型礁系统（emergent reef systems）。然而，大洋浅滩生物区内最常见的礁体类型并未出露海面。这些本质为生物成因（biogenic）的水下礁体（submerged reefs）从深水抬升至海面下10至50米的深度，目前人们对其认知极为匮乏，大部分仍有待探索与特征刻画。作为小型海山（mini seamounts），这类礁体极有可能是生物多样性与生物量富集（biomass accumulation）的区域。本次生物多样性调查的首要任务，是对水下礁体开展普查以刻画区域生物多样性特征，包括礁体内生境的空间分布格局；随后将构建生境类型与潜在生物多样性热点区域分布的区域模型。整合海洋化学、海洋学（oceanography）与地质学（geology）数据，将是帝汶海研究的一大特色，此举将支持针对性多学科项目开展，以解析维持该区域生物群落存续的关键过程。为此，本研究将调查该生物区两项潜在重要特征——陆架边缘上升流现象（shelf edge upwelling phenomena）与天然烃类渗漏（natural hydrocarbon seeps）的分布情况，并将其与生物多样性分布数据进行整合。本报告总结了在帝汶海大洋浅滩生物区内卡姆特浅滩（Karmt Shoals）附近、水深50米与100米处部署的2台仪器化锚泊系统（instrumented moorings）。该锚泊系统于2004年1月布设，2004年4月回收并重新部署，最终于2004年12月完成回收。