Coral reef bacterial communities

Abstract

Tropical coral reefs form some of the richest ecosystems on Earth. Though representing less than 0.1% of the total ocean surface, coral reefs host approximately 25% of all marine species. Along with their high biodiversity, coral reefs support the livelihood of millions of people around the world through supply of food, resources, and coastal protection, plus their natural beauty attracts tourists that support associated industries. Coral reefs are complex three-dimensional structures, with an array of habitats and environmental niches. They are also one of the most vulnerable ecosystems on our planet, currently under direct threat from human activities including climate change, decreased water quality, and increased nutrient loads. The microbial community is fundamental to the functioning, health, and resilience of these coral reef ecosystems. Understanding how environmental stress affects microbial communities and their processes will allow us to better predict the resilience of coral reefs during changes in nutrient cycling and disease epidemics. This chapter explores the important role of microbial communities in keystone reef organisms such as reef-building Scleractinian corals and benthic filter-feeding sponges. These species represent the best studied systems in coral reefs for invertebrate-bacterial interactions. Diversity and function of microbial communities in the sediments and overlying seawater are also explored with microbially driven nutrient cycling in these habitats closely coupled to reef productivity.