12 The Ocean Microbiome and Marine Life
The Ocean Microbiome and Marine Life
The ocean is teeming with life, both macro and micro, where their adaptation and success are dependent on both a local and global scale. Oceanic microorganisms have major roles in nutrient cycling, ecological interactions, and influence and respond to environmental changes (Doney et al., 2012). Temperature is the strongest factor that determines microbial community composition, which parallels depth stratification, and these communities can serve as indicators for anthropogenically-induced climate changes (Sunagawa et al., 2015). It is predicted that carbon fixation by microbial primary producers will decrease which will have downstream effects on ocean microbiome structure and overall trophic level interactions (Moran, 2015).
While free-living marine microorganisms can provide relevant information and predictive models about the ocean, those host-associated microbes can also give environmental insight into the largest ecosystem on the planet.
Marine Animal Microbiomes: Toward Understanding Host–Microbiome Interactions in a Changing Ocean
Article by Apprill, 2017 licensed under the terms of the Creative Commons Attribution License (CC BY).
All animals on Earth form associations with microorganisms, including protists, bacteria, archaea, fungi, and viruses. In the ocean, animal–microbial relationships were historically explored in single host–symbiont systems. However, new explorations into the diversity of microorganisms associating with diverse marine animal hosts is moving the field into studies that address interactions between the animal host and a more multi-member microbiome. The potential for microbiomes to influence the health, physiology, behavior, and ecology of marine animals could alter current understandings of how marine animals adapt to change, and especially the growing climate-related and anthropogenic-induced changes already impacting the ocean environment. This review explores the nature of marine animal–microbiome relationships and interactions, and possible factors that may shift associations from symbiotic to dissociated states. I present a brief review of current microbiome research and opportunities, using examples of select marine animals that span diverse phyla within the Animalia, including systems that are more and less developed for symbiosis research, including two represented in my own research program. Lastly, I consider challenges and emerging solutions for moving these and other study systems into a more detailed understanding of host–microbiome interactions within a changing ocean.
Introduction
Marine animals are the icons of life in the oceans. They represent about two million species (Mora et al., 2011) and include a wide range of body designs, from the highly simplistic sponges lacking true tissues and organs to the complex vertebrates containing specialized tissues and organs, such as fish and marine mammals, with some iconic repres