Remote Monitoring of Giant Kelp Photosynthetic Condition: An Evaluation of the Potential for the Hyperspectral Infrared Imager (HyspIRI) Mission

Abstract:

This study examines the potential of the HyspIRI mission for monitoring the photosynthetic condition of giant kelp forests on global scales. Giant kelp is a highly dynamic foundation species that supports an ecologically and economically important ecosystem. Satellite, airborne, and field data are used to evaluate the suitability of HyspIRI’s spatial, temporal, and spectral coverage for capturing variability in giant kelp photosynthetic pigment state. Spectral variability is explored by assessing how changes in the photosynthetic condition of giant kelp canopy (i.e. pigment and nutrient concentrations) are exhibited in the reflectance and transmittance of kelp fronds. We then compare pigment and nutrient concentrations of kelp fronds to laboratory and airborne measurements of reflectance and transmittance in order to develop spectral metrics of kelp photosynthetic pigment state.

We developed spectral indices that explained 71%, 18%, and 59% of the variance for chlorophyll a, chlorophyll c, and fucoxanthin respectively, and found that HyspIRI will have sufficient spectral resolution and signal to detect these changes in chlorophyll a and fucoxanthin. Our results indicate that the spectral coverage provided by HyspIRI has the potential to provide new insights into the ecology and variability in photosynthetic condition of giant kelp.