The Southwestern Atlantic coral Mussismilia hispida exhibit remarkable tolerance to nitrate enrichment

Author(s)

Patrocinio, Guilherme Toledo Alves ; Lopes, Fernanda Chaves ; Ciotti, aurea Maria ; Faria, Samuel Coelho ; Martins, Camila de Martinez Gaspar

• Document type: Journal article
• Source: CORAL REEFS; v. N/A, p. 14-pg., 2025-02-25.

Abstract

The enrichment of coastal environments with nutrients, particularly nitrate, affects coral reef health. Nitrate enrichment can disrupt coral-algae symbiosis and reduce thermal tolerance, raising concerns in the context of global warming. Considering the naturally high nutrient levels along the Brazilian coast, which are further increased by human activity, we investigated whether nutrients impact the symbiosis, oxidative and energy metabolism, and calcification-related markers in the reef-building coral Mussismilia hispida. We also examined whether temperature modulates this effect, and whether corals can recover from stress once returned to normal conditions. This was done after exposure to nitrate enrichment (30 mu M), both alone and combined with thermal stress (+ 3.5 degrees C), followed by a 14-day recovery period. Nitrate alone had no effects in any of the markers evaluated, while elevated temperature induced oxidative stress, leading to bleaching. However, corals maintained high ATP levels, potentially supporting the activity of calcification enzymes. Nitrate did not amplify the effects of temperature. After recovery, corals exposed to elevated temperature, alone or with nitrate, remained bleached, with reduced symbiosis metrics. Our findings highlight the remarkable tolerance of M. hispida to nitrate enrichment, possibly an adaptation driven by the nutritional profile of Southwestern Atlantic Ocean. The results also suggest that it may not rely heavily on symbionts, as energy homeostasis and growth-related markers are maintained even when corals were fully bleached. (AU)

• FAPESP's process: 22/03105-7 - Using the phylogenetic past to predict climate impacts: ecophysiology of symbiosis and accelerated evolution to coral reef conservation
• Grantee: Samuel Coelho de Faria
• Support Opportunities: Research Grants - Initial Project