Aggregates in aquatic ecosystems and implications for aquacultures

Agglomerations of suspended particulate matter serve various roles in aquatic ecosystems. They participate in nutrient and energy fluxes and are involved in important food web processes. While comprehensive studies on aggregates are available from natural freshwater and marine ecosystems, little is known about the roles of aggregates in aquacultures, particularly in shrimp pond farming. As particle-rich systems, shrimp ponds and marine aquaculture (mariculture) areas constitute interesting objects for aggregate studies, particularly as a source of natural feed, particle fluxes, microbial communities, including pathogenic bacteria, and possible vector of disease widespread. The aims of this review are i) to compile the current knowledge on the role of aggregates in aquatic ecosystems, particularly in aquaculture areas covering advantages and negative side effects of aggregates in aquacultures, ii) to explore the role of aggregates in disease ecology, and iii) perspective of aquaculture management in the context of aggregate utilization and management. Since Southeast Asia, especially Indonesia, is among the most important regions for aquaculture activities, this review focuses on Indonesian aquacultures. Although aquacultures produce important amounts of aggregates, including its associated microbial communities, they are rarely investigated in Indonesian aquacultures, particularly in shrimp pond farming. In contrast, most of the studies focused on bacterial cultivation and utilization of isolates for aquacultures. Thus, understanding the ecological roles of aggregates in aquacultures may support the improvement of aquaculture management and yields.