Microphytobenthos (MPB) plays an integral role in contributing to the productivity and sustenance of shallow marine ecosystem. MPB forms an integral component in the trophic structure of mangrove forest and its biogeochemistry. Microphytobenthos from three selected mangrove ecosystems (S1, Kannur; S2, Kochi and S3, Kollam) along the southwest coast of India was studied in detail for 1 year (2018–2019). Spatial and temporal (seasonal) variations in the community structure were addressed along with major environmental factors influencing the pattern of distribution. A total of 148 species of microphytobenthos under 58 genera were identified during the study. Diatoms (Bacillariophyceae) were the most abundant and diverse class of MPB present followed by Cyanophyceae, Dinophyceae and Euglenophyceae. The analysis of physicochemical parameters showed that salinity, temperature, sediment texture and nutrient characteristics were the major factors governing the community structure of MPB. Seasonally, maximum abundance was observed during monsoon and pre-monsoon with lesser diversity and extensive mats of cyanobacteria dominated by Oscillatoria spp. However, post-monsoon season with high nutrient concentration, increased salinity and more of sandy sediment texture supported diverse assemblage of diatoms. Dominant diatoms observed were Amphora spp., Diploneis sp., Navicula spp., Nitzschia spp., Pleurosigma sp. and Gyrosigma sp. Regionally, S3 Kollam was observed to be more diverse with the dominance of diatoms, whereas S2 Kochi observed lesser diversity with cyanobacterial dominance. Increased sediment grain size (sand ~ 68%) favoured diverse diatom assemblage at S3 resulting in an overall high MPB diversity of the area than S1 and S2.

微型底栖动物（MPB）在促进浅海生态系统的生产力和维持方面起着不可或缺的作用。MPB是红树林营养结构及其生物地球化学不可或缺的组成部分。对印度西南海岸三个选定的红树林生态系统（S1，Kannur； S2，Kochi和S3，Kollam）的微底栖鱼类进行了为期一年（2018-2019）的详细研究。解决了社区结构的时空（季节性）变化以及影响分布格局的主要环境因素。在研究过程中，共鉴定了58个属下的148种微底栖细菌。硅藻（芽孢杆菌科）是目前存在的最丰富和最多样化的MPB类，其次是蓝藻科，迪诺藻科和裸藻科。理化参数分析表明，盐度，温度，沉积物质地和养分特征是影响MPB群落结构的主要因素。季节性地，在季风和季风前期观察到最大丰度，多样性较低，且蓝藻垫席广泛，主要由颤藻属 但是，季风后季节的养分含量高，盐分增加，沙质沉积物更多，这支持了硅藻的各种组装。观察主导硅藻安芙兰属，Diploneis属，舟形属，菱形藻属，Pleurosigma SP。和Gyrosigma sp。在区域上，S3 Kollam的硅藻占优势，多样性更高，而S2 Kochi的蓝藻占优势，多样性更低。沉积物粒度的增加（约68％的沙粒）有利于S3处硅藻的多样性，从而导致该地区的MPB总体上高于S1和S2。