Calculating dissolved marine oxygen values based on an enhanced Benthic Foraminifera Oxygen Index

Area of Science:

• Marine geology and paleoceanography
• Biogeochemical cycles
• Climate change research

Background:

• Marine oxygen minimum zones (OMZs) are critical for global biogeochemical cycles and marine ecosystems.
• Dissolved oxygen (DO) levels are a key factor in OMZ dynamics, influencing habitat availability and greenhouse gas sequestration.
• Existing methods like the Benthic Foraminifera Oxygen Index (BFOI) have limitations in accurately reconstructing past DO levels.

Purpose of the Study:

• To enhance the Benthic Foraminifera Oxygen Index (BFOI) for more accurate reconstruction of dissolved oxygen (DO).
• To develop a novel transfer function for direct conversion of enhanced BFOI (EBFOI) values to DO concentrations.
• To provide improved tools for understanding past and predicting future changes in marine oxygen levels and eutrophication.

Main Methods:

• Developed enhanced Benthic Foraminifera Oxygen Index (EBFOI) formulas incorporating all available benthic foraminifera data.
• Calculated the complete habitable space for benthic foraminifers, including bottom water oxygenation (BWO) and pore water oxygenation (PWO).
• Created and calibrated a new transfer function linking EBFOI values to DO concentrations using modern and fossil datasets.

Main Results:

• The enhanced BFOI (EBFOI) method utilizes comprehensive benthic foraminifera data, including BWO and PWO.
• A novel transfer function enables direct conversion of EBFOI to DO values with up to 38% increased efficiency.
• Calibrated formulas applied to modern and fossil datasets demonstrate significant improvements in DO reconstruction.

Conclusions:

• The EBFOI represents a major advancement in reconstructing marine oxygen levels and identifying eutrophication.
• This new approach provides a robust toolset for analyzing past oceanic changes and tracking current/future OMZ expansion.
• Improved DO reconstructions are crucial for understanding the ecological and biogeochemical impacts of expanding OMZs.