Climate forcing of regional deep-sea biodiversity documented by benthic foraminifera

The biodiversity of deep-sea ecosystems is closely linked to orbital and suborbital climate changes during the late Quaternary as documented by the diversity and species composition of benthic foraminifera. The benthic foraminiferal diversity changes are mainly driven by variations in food fluxes and bottom-and pore-water oxygenation with distinct regional differences. Overall, the observed regional diversity patterns suggest that highly diverse deep-sea ecosystems are more resilient to perturbations such as drops in oxygen than low-diverse ecosystems, supporting the Diversity-Stability Hypothesis. Seasonal phytodetritus pulses in oligotrophic and well-ventilated deep-sea ecosystems commonly result in a dominance of opportunistic taxa and low diversity. Regional diversity contrasts between the Last Glacial Maximum (LGM) and the Holocene increase with increasing water depth. During the LGM, relatively lower diversity occurs in the deeper parts of the Nordic Seas, Atlantic Ocean, Southern Ocean and Indian Ocean but higher diversity in the Mediterranean Sea and Red Sea. The deep basins of open-ocean ecosystems profit from a stronger interglacial ventilation, while in marginal basins, warm and humid climate conditions during insolation maxima repeatedly result in a temporal reduction or cessation of deep-water formation with transient collapses of deep-sea ecosystems. Understanding the underlying processes of past changes in the diversity of deep-sea benthic foraminifera is useful for assessing the stability of modern deepsea ecosystems with respect to potential impacts of future climate change and local anthropogenic perturbations.

Automated summary

The biodiversity of deep-sea ecosystems is influenced by climate changes and resource availability. The diversity and species composition of benthic foraminifera serve as indicators of these changes. Highly diverse deep-sea ecosystems are more resilient to disturbances, while oligotrophic and well-ventilated ecosystems experience lower diversity due to seasonal pulses of phytodetritus.