Benthic Foraminifera in Paleoceanography and Environmental Change

Benthic foraminifera are single-celled marine protists that inhabit the seabed and build calcareous or agglutinated tests. Their widespread distribution and rapid environmental sensitivity make them indispensable proxies for reconstructing past ocean conditions, including temperature, oxygenation, productivity and circulation patterns. In paleoceanography, fluctuations in foraminiferal assemblages recorded in sediment cores reveal shifts in bottom-water oxygen levels, organic matter supply and faunal turnover driven by climate perturbations. Quantitative methods—such as assemblage-based transfer functions, trait analysis and morphometric measurements—have refined interpretations of oxygen minimum zones and carbon cycling through geological time. Seminal studies of mass extinctions in the deep sea demonstrate the coupling of benthic foraminiferal diversity with phytoplankton evolution and productivity changes, underscoring the sensitivity of seafloor ecosystems to global biogeochemical feedbacks. Modern baselines, incorporating living and dead assemblages from diverse ocean basins, underpin robust calibrations for paleo-oxygen reconstructions and serve as ecological benchmarks for assessing ongoing ocean deoxygenation. The integration of trait-based approaches, enhanced oxygen indices and large-scale sediment-core databases continues to advance our understanding of seafloor ecosystem responses to past and future environmental change, informing predictions of habitat loss and carbon sequestration in a warming world.

Research from Nature Portfolio

Recent studies have applied trait analysis to benthic foraminiferal assemblages from Arctic cores spanning the last 14,000 years. By assigning ecological attributes—such as oxygen tolerance and feeding strategy—to species, abrupt community shifts across the deglacial–Holocene transition and mid-Holocene warming were linked directly to variations in bottom-water oxygen and climate forcing. An enhanced oxygen index has also been introduced, combining full assemblage data with pore-water and bottom-water indicators to reconstruct past dissolved oxygen values more accurately. This new framework employs calibrated formulas that translate combined biological signals into quantitative oxygen estimates, improving efficiency and precision over traditional indices by up to 38%. Foundational work on deep-sea mass extinction events during the Mid Pleistocene further illustrates how benthic foraminiferal losses coincide with phytoplankton evolution, revealing links between seasonal productivity shifts and benthic biodiversity declines on a global scale.

Benthic Foraminifera in Paleoceanography and Environmental Change publication trend

The graph below shows the total number of articles in benthic foraminifera in paleoceanography and environmental change across all publications each year (not limited to Nature Index journals).

Technical terms

Benthic foraminifera: Single-celled protists with calcareous or agglutinated tests living on or within seafloor sediments.

Paleoceanography: The study of past ocean conditions and their interactions with climate through geological records.

Oxygen Minimum Zone (OMZ): A seafloor region characterised by markedly low dissolved oxygen, often linked to high organic matter decomposition.

Trait analysis: Assignment of ecological or physiological characteristics to species to assess faunal responses to environmental change.

Morphometric analysis: Quantitative measurement of test shape and size to infer past environmental parameters.

Transfer function: A statistical relationship converting biological or geochemical indicators into quantitative environmental variables.

Enhanced Benthic Foraminifera Oxygen Index (EBFOI): An improved proxy integrating full faunal composition and test data to reconstruct past dissolved oxygen levels accurately.

References

1. BENFEP: a quantitative database of benthic foraminifera from surface sediments of the eastern Pacific. Earth System Science Data (2023).
2. Response of Arctic benthic foraminiferal traits to past environmental changes. Scientific Reports (2023).
3. Mid Pleistocene foraminiferal mass extinction coupled with phytoplankton evolution. Nature Communications (2016).
4. Toward a global calibration for quantifying past oxygenation in oxygen minimum zones using benthic Foraminifera. Biogeosciences (2021).
5. Bottom-water deoxygenation at the Peruvian margin during the last deglaciation recorded by benthic foraminifera. Biogeosciences (2020).
6. Calculating dissolved marine oxygen values based on an enhanced Benthic Foraminifera Oxygen Index. Scientific Reports (2022).