Precision and cost-effectiveness of bioindicators to estimate nutrient regimes on coral reefs

Bioindicators are useful for determining nutrient regimes in marine environments, but their ability to evaluate corals reefs different ecological states is poorly understood. The precision, availability and congruency of eight potential bioindicators (brown macroalgae, green turf algae, cyanobacteria, soft corals, zoanthids, sponges, sediment) stable isotopic elemental signatures (δ15N, δ13C, %N, %C, C:N Ratio) were assessed across 21 the Inner Seychelles. coefficient variation (CoV) δ15N showed that brown macroalgae highly precise (2.47 ± 0.95, n = 11; 4.68 1.33, 16, respectively), though less common on coral-mortality relative macroalgal-dominated ones. Zoanthids also (2.98 1.20), more readily available regardless reef state (n 18). Congruency was low among these indicators, suggesting physiological mechanisms processing have a stronger influence bioindicator's effectiveness than state.