Effect of hydro-climate variation on biofilm dynamics and its impact in intertidal environments
Effect of hydro-climate variation on biofilm dynamics and its impact in intertidal environments
复制标题
DOI：
10.5194/esurf-10-1115-2022
复制
发表时间：
2022-11
影响因子：
3.4
通讯作者：
E. Bastianon;J. Hope;R. Dorrell;D. Parsons
中科院分区：
文献类型：
--
作者：
E. Bastianon;J. Hope;R. Dorrell;D. Parsons
抽象的。浅水潮汐环境是非常有生产力的生态系统，但对环境变化和海平面上升很敏感。因此，这些环境的生物形态动力学控制是一个至关重要的考虑因素，然而，小规模的生物活动对大规模的粘性沉积物动力学，如潮汐盆地和河口的影响在很大程度上仍然是无法量化的。本研究通过评估生物和非生物因素对生物粘性沉积物输运和形态的影响，推进了我们的理解。一个理想的底栖生物膜模型被纳入一维形态动力学模型的潮汐为主的渠道。本研究探讨了一系列环境和生物条件对生物膜生长的影响，以及它们对整个潮间带通道形态演变的反馈。通过对生物形态动力学模型进行敏感性分析，系统地改变了（i）水动力扰动、（ii）季节性、（iii）生物膜生长速率、（iv）温度变化和（v）沉积物的生物粘性等参数。结果表明，关键参数，如生长速率和温度强烈影响生物膜的发展，是一系列干扰周期和强度下的平衡生物膜的配置和发展的关键决定因素。潮间带通道发展的长期模拟表明，潮汐引起的水动力扰动在塑造床的形态中起着关键作用，表面生物膜的存在增加了达到形态平衡的时间。在水动力低的地方，生物膜生长并稳定床层，抑制粗沉积物（中砂和细砂）的运输。这些研究结果表明，生物膜的存在下，在潮间带通道，有显着不同的特点，在形态和地层相比，非生物沉积物的通道床的结果。因此，在形态动力学模型中考虑生物凝聚力对预测河口发展和减缓海岸侵蚀是必要的。
Abstract. Shallow tidal environments are very productive ecosystems but are sensitive to environmental changes and sea level rise. Bio-morphodynamic control of these environments is therefore a crucial consideration; however, the effect of small-scale biological activity on large-scale cohesive sediment dynamics like tidal basins and estuaries is still largely unquantified. This study advances our understanding by assessing the influence of biotic and abiotic factors on biologically cohesive sediment transport and morphology. An idealised benthic biofilm model is incorporated in a 1D morphodynamic model of tide-dominated channels. This study investigates the effect of a range of environmental and biological conditions on biofilm growth and their feedback on the morphological evolution of the entire intertidal channel. By carrying out a sensitivity analysis of the bio-morphodynamic model, parameters like (i) hydrodynamic disturbances, (ii) seasonality, (iii) biofilm growth rate, (iv) temperature variation and (v) bio-cohesivity of the sediment are systematically changed. Results reveal that key parameters such as growth rate and temperature strongly influence the development of biofilm and are key determinants of equilibrium biofilm configuration and development under a range of disturbance periodicities and intensities. Long-term simulations of intertidal channel development demonstrate that the hydrodynamic disturbances induced by tides play a key role in shaping the morphology of the bed and that the presence of surface biofilm increases the time to reach morphological equilibrium. In locations characterised by low hydrodynamic forces, the biofilm grows and stabilises the bed, inhibiting the transport of coarse sediment (medium and fine sand). These findings suggest biofilm presence in channel beds results in intertidal channels that have significantly different characteristics in terms of morphology and stratigraphy compared abiotic sediments. It is concluded that inclusion of bio-cohesion in morphodynamic models is essential to predict estuary development and mitigate coastal erosion.