Benthic Foraminifera as Indicators of Coral Reef Health

Benthic foraminifera are unicellular, shelled protists that inhabit reef sediments and surfaces, forming diverse assemblages closely linked to environmental conditions. Their calcified tests record changes in temperature, pH, nutrient load and light availability, making them sensitive barometers of reef vitality. Shifts in species composition, test morphology and population density can reveal early stages of stress from warming, acidification, eutrophication and pollution. Photo-symbiotic species, which host microalgae within their tests, mirror coral bleaching responses and contribute substantially to carbonate production, influencing sediment budgets and reef accretion. As rapid responders with well-preserved fossil records, benthic foraminifera bridge modern monitoring and palaeo-ecological reconstructions, offering insights into both short-term disturbances and long-term reef trajectories. Their global distribution and clear habitat preferences enable standardised indices for water-quality assessment and risk evaluation, supporting conservation, management and restoration of coral ecosystems under changing climate regimes.

Research from Nature Portfolio

Recent studies have elucidated how range shifts and biodiversity patterns of symbiont-bearing foraminifera reflect reef perturbations and broader biogeographical changes. One investigation into the Mediterranean invasion of Amphistegina lobifera demonstrated that this species’ high dispersal ability and pre-adaptation to warmer conditions facilitate its expansion into novel reef-like habitats, even as genetic diversity within populations declines. This work highlights how altering community composition can serve as an indicator of ocean warming and the restructuring of carbonate-producing assemblages. A complementary effort mapped global species richness of larger benthic foraminifera across the Indo-Pacific, revealing the Central Philippines as a diversity hotspot shaped by sea surface temperature and nutrient gradients. These species distribution models establish baseline diversity patterns against which future shifts—driven by climate change and local stressors—can be monitored to assess reef health and resilience.

Benthic Foraminifera as Indicators of Coral Reef Health publication trend

The graph below shows the total number of articles in benthic foraminifera as indicators of coral reef health across all publications each year (not limited to Nature Index journals).

Technical terms

Benthic foraminifera: Unicellular protists with calcareous shells living on or within marine sediments, sensitive to environmental change.

Photo-symbiosis: A mutually beneficial association between a host (e.g. foraminifera) and photosynthetic microalgae.

Calcification: The biological process by which organisms precipitate calcium carbonate to form shells or skeletons.

Holobiont: The combined assemblage of a host organism and its associated microbial partners, functioning as an ecological unit.

References

1. Invasion success of a Lessepsian symbiont-bearing foraminifera linked to high dispersal ability, preadaptation and suppression of sexual reproduction. Scientific Reports (2023).
2. Symbiosis and microbiome flexibility in calcifying benthic foraminifera of the Great Barrier Reef. Microbiome (2017).
3. Patterns of species richness and the center of diversity in modern Indo-Pacific larger foraminifera. Scientific Reports (2018).
4. Response of large benthic foraminifera to climate and local changes: Implications for future carbonate production. Sedimentology (2021).