Embayments and the biota they support are highly susceptible to disturbance within adjacent catchments. Examining the timing and magnitude of impacts arising from human-induced disturbance in these systems is often limited due to the absence of long-term monitoring. Moreton Bay in south-eastern Queensland is a shallow embayment that receives inflows from a 21220-km2 catchment. In this study, diatom abundances, pigment (chlorophyll-a, phaeopigments) and biogenic silica concentrations were evaluated in a composite sediment from central Moreton Bay to explore temporal trends in the photosynthetic community. The record extends from 1200 to 2011, incorporating the period of European settlement (c. 1840s) and rapid population growth and urbanisation of the catchment. The record shows that in central Moreton Bay bloom-forming marine diatoms (Thalassiosira, Thalassiothrix, Thalassionema) have increased in relative abundance since the mid-20th century, whereas the dominant benthic diatom (Paralia fenestrata) has declined. This transition most likely occurred in response to the compounding effects of increased delivery of nitrogen, fine sediments and pollutants to Moreton Bay as a consequence of changes in land use. The inferred historical decline in relative contributions of benthic microalgae to total primary production in central Moreton Bay has likely had wide-ranging ecological effects.

中文翻译：

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澳大利亚摩顿湾硅藻群落对集水区土地利用变化的反应记录

海湾及其支持的生物群极易受到相邻流域内的干扰。由于缺乏长期监测，对这些系统中人为干扰产生的影响的时间和影响程度的研究往往受到限制。昆士兰东南部的摩顿湾是一个浅海湾，接收来自 21220 平方公里集水区的流入。在这项研究中，评估了来自摩顿湾中部的复合沉积物中的硅藻丰度、色素（叶绿素-a、褐素）和生物二氧化硅浓度，以探索光合群落的时间趋势。该记录从 1200 年延续到 2011 年，包括欧洲定居时期（约 1840 年代）以及该流域的快速人口增长和城市化。记录显示，自 20 世纪中叶以来，在莫顿湾中部形成水华的海洋硅藻（Thalassiosira、Thalassiothrix、Thalassionema）相对丰度有所增加，而占优势的底栖硅藻（Paralia fenestrata）则有所减少。这种转变很可能是由于土地利用变化导致向摩顿湾输送的氮、细粒沉积物和污染物增加的复合效应。底栖微藻对莫顿湾中部初级生产总量的相对贡献的推断历史下降可能具有广泛的生态影响。这种转变很可能是由于土地利用变化导致向摩顿湾输送的氮、细粒沉积物和污染物增加的复合效应。底栖微藻对莫顿湾中部初级生产总量的相对贡献的推断历史下降可能具有广泛的生态影响。这种转变很可能是由于土地利用变化导致向摩顿湾输送的氮、细粒沉积物和污染物增加的复合效应。底栖微藻对莫顿湾中部初级生产总量的相对贡献的推断历史下降可能具有广泛的生态影响。