Microphytobenthos primary production estimated by hyperspectral reflectance

Area of Science:

• Ecology
• Remote Sensing
• Plant Physiology

Background:

• Remote sensing enables ecosystem-level monitoring of photosynthesis and primary productivity.
• Intertidal mudflats host diverse microphytobenthos (MPB) crucial for primary production.
• Accurate measurement of MPB primary production is essential for understanding coastal ecosystem health.

Purpose of the Study:

• Develop a novel remote sensing-based method for quantifying MPB primary production.
• Couple hyperspectral radiometry and PAM-fluorometry for robust measurements.
• Identify a species- and growth-form-independent radiometric index for predicting key photosynthetic parameters.

Main Methods:

• Utilized hyperspectral radiometry (reflectance, second derivative) and PAM-fluorometry (non-sequential light curves).
• Measured pigment composition, optical absorption cross-section (a*), light use efficiency (LUE), and electron transport rates (ETR).
• Tested five representative MPB species across a gradient of light intensities.

Main Results:

• Observed distinct fluorescence patterns linked to the xanthophyll cycle across different MPB growth forms.
• Retrieved a* using a radiative transfer model and evaluated radiometric indices.
• Identified a single, non-species/growth-form-specific index, δδ496/508 (MPBLUE), capable of predicting LUE and ETR.

Conclusions:

• The MPBLUE index offers a promising tool for remote sensing of MPB primary production.
• This method is applicable across various hyperspectral sensor resolutions.
• The study advances our ability to monitor coastal primary productivity using remote sensing.