Reef biofilms under chronic nutrient enrichment

At present, work on marine biofilms has primarily focused on host-associated habitats for their roles in larval recruitment and disease dynamics; little is known about the factors regulating the composition of reef environmental biofilms. To contrast the roles of succession, benthic communities, and nutrients in structuring marine biofilms, we surveyed bacteria communities in biofilms through a six-week succession in aquaria containing macroalgae, coral, or reef sand factorially crossed with three levels of continuous nutrient enrichment. We hypothesized that the organic resources derived from the surrounding benthic organisms and inorganic nutrient availability would work interactively and orthogonally to influence biofilm assembly and succession. Over the course of six weeks, we tested the effect of constituent benthic organisms (corals, algae, and sand-associated microphytobenthos) and sustained nutrient loads on the successional dynamics of developing marine biofilms on glass slides.

当前，海洋生物膜（marine biofilms）相关研究主要聚焦于宿主关联生境，关注其在幼体招募与疾病动态中的功能；但目前学界对调控珊瑚礁环境生物膜群落组成的影响因素仍知之甚少。为对比演替、底栖群落（benthic communities）与营养盐在塑造海洋生物膜群落结构中的作用，本研究采用析因实验设计，设置底栖底物（大型藻类（macroalgae）、珊瑚（coral）、礁沙（reef sand））与连续营养富集水平（三个梯度）两个因素，在对应水族箱中开展为期六周的生物膜演替观测，以此对生物膜内的细菌群落进行系统调查。我们提出假说：周围底栖生物产生的有机资源与无机营养盐有效性，将以交互与正交的方式共同作用，影响生物膜的组装与演替过程。在六周的实验周期内，我们通过玻璃载玻片上发育的海洋生物膜，探究了基底底栖生物（珊瑚、藻类及沙相关微型底栖微藻（microphytobenthos））与持续营养盐负荷对生物膜演替动态的调控效应。