Multi-scale spectroscopy to map intertidal microbial biofilm community and trait diversity

JGR Biogeosciences
By: , and 

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Abstract

Intertidal microbial biofilms, or microphytobenthos, support estuarine biogeochemical cycling, the physical stability of mudflats, and food webs, particularly those of migratory shorebirds. Photosynthetic biofilms dominated by diatoms, cyanobacteria, and chlorophytes represent a significant fraction of biofilm biomass and contain pigments that can be detected with remote sensing. These diverse biofilm community types vary in indicator pigments and functional traits related to biogeochemical cycling and nutritional quality. We modeled and mapped spatial variation in intertidal biofilm distribution, quantity, diversity, and functional traits using multi-scale spectroscopic data collected within southern San Francisco Bay, California, USA (South SFB). We developed a new biofilm index (B-index) from 5 mm HySpex spectra to detect biofilm presence. We developed single and multiple response partial least squares regression (PLS) models of chlorophyll-a (chl-a; biomass indicator), indicator pigments: fucoxanthin and diadinoxanthin (diatoms), zeaxanthin (cyanobacteria), and chl-b (chlorophytes), and functional traits: carbohydrates, lipids, and total organic carbon from paired in situ biofilm data and field spectra. The B-index and PLS models were scaled to South SFB with a 3.7 m AVIRIS-NG hyperspectral image. The model %RMSE calculated from AVIRIS-NG test samples ranged from 12.7% for chl-a to 49% for chl-b; for six of the eight models, %RMSE was 23% or below. Mapped community types differed in mapped traits, with average lipid concentrations three times higher in areas indicated as diatoms compared to other groups. Available maps depict for the first time the spatial variation of an important shorebird food resource and inform the contribution of intertidal biofilm in carbon and nutrient cycling.

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Publication type Article
Publication Subtype Journal Article
Title Multi-scale spectroscopy to map intertidal microbial biofilm community and trait diversity
Series title JGR Biogeosciences
DOI 10.1029/2024JG008520
Volume 130
Issue 6
Publication Date June 05, 2025
Year Published 2025
Language English
Publisher American Geophysical Union
Contributing office(s) Western Geographic Science Center
Description e2024JG008520, 23 p.
Country United States
State California
Other Geospatial South San Francisco Bay
Additional publication details