WAMSI 2 - Kimberley Node - Project 2.2.4 Benthic primary productivity, production and herbivory of seagrasses, macroalgae and microalgae

Primary producers play significant roles in coastal processes and ecological function. These roles include provision of habitat, stabilising substrates and provision of a food source to fauna. Currently, there are very few studies on primary producers in the Kimberley region, contributing to the poor understanding of processes and adaptive mechanisms under extreme environmental conditions. The project has focussed on the data deficient components of benthic primary producers: seagrasses, macroalgae and sediment microalgae and bacterial communities. The objectives of the project were to (a) understand the temporal and spatial variations in biomass and productivity of seagrasses, macroalgae and benthic microalgae (b) investigate the rates and magnitude of microbial carbon and nitrogen cycling processes, and how they influence primary production and (c) to investigate the rates and net effect of herbivory on seagrasses, macroalgae and benthic microalgae.The seasonal and spatial variability in biomass and growth of selected species of seagrasses and seaweeds was measured during 5 surveys at 5 sites in the Bardi Jawi Indigenous Protected Area (on dates during 2013-2015). The productivity, carbon processes and nutrient cycling of microalgae and bacteria in intertidal and shallow subtidal sediment was also measured. Rates of herbivory were measured at 3 sites during 4 surveys. Stable isotope ratios of the major primary producers were measured at 5 sites.

初级生产者（primary producers）在海岸过程与生态功能中发挥着关键作用，其生态功能包括提供栖息生境、稳定底质以及为动物群落提供食物来源。目前针对金伯利地区（Kimberley）的初级生产者研究极少，导致学界对极端环境下的海岸过程与生物适应机制的认知较为匮乏。本项目聚焦于数据匮乏的底栖初级生产者（benthic primary producers）类群：海草（seagrasses）、大型藻类（macroalgae）、沉积物微藻（sediment microalgae）以及细菌群落（bacterial communities）。本项目的研究目标包括：(a) 解析海草、大型藻类与底栖微藻的生物量及生产力的时空变异规律；(b) 探究微生物碳、氮循环过程的速率与强度，及其对初级生产的调控机制；(c) 探明植食作用对海草、大型藻类与底栖微藻的作用速率与净效应。研究团队于2013-2015年间，在巴迪贾维土著保护区（Bardi Jawi Indigenous Protected Area）的5个采样点开展5次野外调查，测定了选定海草与大型藻类物种的生物量及生长的季节与空间变异特征。同时测定了潮间带（intertidal）与浅亚潮带（shallow subtidal）沉积物中微藻与细菌的生产力、碳循环过程与养分循环速率。研究团队在3个采样点开展4次调查，测定了植食作用速率；并在5个采样点测定了主要初级生产者的稳定同位素比值。