Data from: Nutrient starvation impairs the trophic plasticity of reef-building corals under ocean warming

1) Global warming of the world’s oceans is driving reef-building corals
towards their upper thermal limit, inducing bleaching, nutrient starvation
and mortality. In addition, corals are predicted to experience large
fluctuations in seawater nutrient concentrations, following water column
stratification or eutrophication problems, which can further alter their
nutritional capacities and ultimately their resilience to global change.
2) We investigated the effect of thermal stress and dissolved inorganic
nutrient (DINUT) availability on the auto- and heterotrophic nutritional
capacities of corals. In particular, we assessed the effect of nitrogen
enrichment or DINUT depletion (both in nitrogen and phosphorus) on the
assimilation of heterotrophic nutrients as well as on the heat-stress
tolerance of the reef-building coral Stylophora pistillata. 3) Here, we
show that DINUT depletion enhanced coral bleaching under thermal stress
and more importantly, significantly impaired rates of heterotrophic
nutrient assimilation, inducing coral starvation. In contrast, corals
grown under nitrogen enrichment maintained high rates of heterotrophic
nutrient assimilation and avoided bleaching, although nutrient uptake
rates were lowered. We therefore observed a positive coupling between
auto-and heterotrophy within the coral-dinoflagellate symbiosis,
indicating that heterotrophic processes require a minimum of
autotrophically-acquired nutrients to be functional. 4) These findings
show that the trophic plasticity of corals directly depends on the
availability of dissolved inorganic nutrients in seawater. The lack of a
shift toward greater heterotrophy under DINUT depletion may lead to
substantial modifications of the role that feeding plays in the response
of reef-building corals to climate change.