Strain Elisabeth M A, Bugnot Ana B, Hancock Boze, Fulweiler Robinson W, Ross Donald J, Reeves Simon E
Institute for Marine and Antarctic Science, University of Tasmania, Hobart, Tasmania, Australia; Centre for Marine Socioecology, University of Tasmania, Hobart, Tasmania, Australia.
CSIRO Environment, St. Lucia, Queensland, Australia.
Mar Environ Res. 2024 Nov;202:106782. doi: 10.1016/j.marenvres.2024.106782. Epub 2024 Oct 10.
Oyster reefs are critically endangered coastal habitats which provide valuable ecosystems services. Despite their importance, there remains a significant knowledge gap in our understanding of how oyster and sediment characteristics influence the ecological functioning and biodiversity of remnant Australian flat oyster (Ostrea angasi) reefs. To inform restoration efforts, we assessed relationships between community respiration rates (CR), inorganic nitrogen fluxes, filtration rates, biodiversity, and oyster morphometrics as well as sediment conditions for three remanent flat oyster reefs (Oyster Cove, Ralphs Bay, and Quarantine Bay) in southeast Tasmania. Additionally, we explored relationships between net denitrification, and flat oyster morphometrics and sediment conditions at one of the sites (Ralphs Bay) in southeast Tasmania. We observed positive relationships between CR, inorganic nitrogen fluxes, filtration rates, and live flat oyster biomass, as well as between the richness and biomass of associated taxa and total flat oyster biomass (both tissue and shell including dead shell), across all three locations. We also found an increase in net denitrification associated with live oyster biomass at one of the oyster reefs (Ralphs Bay). The CR, inorganic nitrogen fluxes, filtration rates, diversity of taxa and biomass of bivalves and flat oyster biomass was higher at Ralphs Bay, which has the most intact reef, compared to the other two locations. In contrast to other studies, the organic and silt content of the sediment showed limited influence on CR, inorganic nitrogen fluxes, filtration rates and net denitrification. CR, and inorganic nitrogen fluxes in these flat oyster reefs were like other restored and natural oyster reefs globally, but net denitrification, filtration rate and taxonomic richness exceeded those previously observed globally. These results highlight the important role of oyster biomass in enhancing water quality and biodiversity. Burgeoning flat oyster reef restoration initiatives should prioritise the enhancement of both live oyster populations and dead shells to recover their associated ecological functions and biological diversity.
牡蛎礁是极度濒危的沿海栖息地，能提供重要的生态系统服务。尽管其重要性不言而喻，但在我们对牡蛎和沉积物特征如何影响澳大利亚残余扁平牡蛎（Ostrea angasi）礁的生态功能和生物多样性的理解上，仍存在重大知识空白。为指导恢复工作，我们评估了塔斯马尼亚东南部三个残余扁平牡蛎礁（牡蛎湾、拉尔夫斯湾和检疫湾）的群落呼吸率（CR）、无机氮通量、过滤率、生物多样性、牡蛎形态测量以及沉积物条件之间的关系。此外，我们还探究了塔斯马尼亚东南部其中一个地点（拉尔夫斯湾）的净反硝化作用与扁平牡蛎形态测量和沉积物条件之间的关系。我们观察到，在所有三个地点，CR、无机氮通量、过滤率与活扁平牡蛎生物量之间存在正相关关系，相关类群的丰富度和生物量与总扁平牡蛎生物量（包括组织和壳，含死壳）之间也存在正相关关系。我们还发现，在其中一个牡蛎礁（拉尔夫斯湾），净反硝化作用随活牡蛎生物量增加。与其他两个地点相比，拉尔夫斯湾的礁体最为完整，其CR、无机氮通量、过滤率、双壳类生物分类多样性和生物量以及扁平牡蛎生物量更高。与其他研究不同的是，沉积物的有机和淤泥含量对CR、无机氮通量、过滤率和净反硝化作用的影响有限。这些扁平牡蛎礁的CR和无机氮通量与全球其他恢复和天然牡蛎礁类似，但净反硝化作用、过滤率和分类丰富度超过了此前全球观测到的水平。这些结果凸显了牡蛎生物量在改善水质和生物多样性方面的重要作用。蓬勃发展的扁平牡蛎礁恢复倡议应优先增加活牡蛎数量和死壳，以恢复其相关的生态功能和生物多样性。
