Developing isotopic markers for trophic mode and resilience in corals.

How does the extent of mixotrophy in corals (i.e. relative contributions of autotrophy vs. heterotrophy) affect 13C and 15N (and possibly D) isotope signatures of coral symbiont vs. host tissue, as well as in the skeleton? In using isotope signatures to define isotopic niches of corals, which interpretation of isotopic data is more reliable and reproducible?

Are there compound specific isotopic markers that can act as a proxy for mixotrophy in corals? If these markers are present in the organic skeletal matrix, would they be preserved in the historical/pre-historical record, to enable estimations of past coral mixotrophy, trophy variation with environmental change, or sub-lethal bleaching events?

How do environmental factors affect coral trophic strategies? How do coral trophic strategies vary amongst different genera? What implications will this have for coral survival through climate change stressors (e.g. ocean acidification and rising temperatures), given that coral heterotrophic plasticity is strongly associated with coral resilience1?