Marine tannins: the importance of a mechanistic framework for predicting ecological roles

Since chemical ecology emerged as a field of marine science, it has been strongly influenced by studies of chemically mediated interactions in land-based systems. Marine chemical ecologists, like their terrestrial counterparts, initially focused on identifying natural products and evaluating the potential ecological roles of these products as defenses, attractants, or other cues. Now, like our land-based colleagues, we must increase our focus on the physiological and biochemical mechanisms that underlie the chemical interactions, paying particular attention to regulation of biosynthetic pathways, within-plant and between-plant signaling cues, and comparative and functional genomics. Here, we review the current state of knowledge regarding a heterogenous group of macrophyte natural products, the marine tannins and simple phenolics, to illustrate how such information is critical to future attempts to predict their ecological roles.