2006, pp 475-507

Marine Chemosynthetic Symbioses

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Introduction

Bacteria and marine eukaryotes often coexist in symbioses that significantly influence the ecology, physiology and evolution of both partners. De Bary (1879) defined symbiosis as “the living together of differently named organisms,” implying that the term encompasses both positive (e.g., mutualism) and negative (e.g., parasitism) associations. Many researchers now view symbiotic interactions as those that persist over the majority of the lifespan of the organisms involved and that provide benefits to each partner beyond those obtained in the absence of association. This chapter describes such symbioses, specifically those between marine invertebrate and protist hosts and chemosynthetic bacterial symbionts.

These bacteria, which cluster primarily within the Gammaproteobacteria (Fig. 1), are chemoautotrophs or methanotrophs. In both chemoautotrophic and methanotrophic symbioses, the hosts, through an astonishing array of physiological and behavioral adaptations, pr