Detection and quantification of snow algae with an airborne imaging spectrometer

Citation
Th. Painter et al., Detection and quantification of snow algae with an airborne imaging spectrometer, APPL ENVIR, 67(11), 2001, pp. 5267-5272
Citations number
22
Categorie Soggetti
Biology,Microbiology
Journal title
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
ISSN journal
00992240 → ACNP
Volume
67
Issue
11
Year of publication
2001
Pages
5267 - 5272
Database
ISI
SICI code
0099-2240(200111)67:11<5267:DAQOSA>2.0.ZU;2-O
Abstract
We describe spectral reflectance measurements of snow containing the snow a lga Chlamydomonas nivalis and a model to retrieve snow algal concentrations from airborne imaging spectrometer data. Because cells of C. nivalis absor b at specific wavelengths in regions indicative of carotenoids (astaxanthin esters, lutein, beta -carotene) and chlorophylls a and b, the spectral sig nature of snow containing C. nivalis is distinct from that of snow without algae. The spectral reflectance of snow containing C. nivalis is separable from that of snow without algae due to carotenoid absorption in the wavelen gth range from 0.4 to 0.58 mum and chlorophyll a and b absorption in the wa velength range from 0.6 to 0.7 mum. The integral of the scaled chlorophyll a and b absorption feature (I-0.68) varies with algal concentration (C-a). Using the relationship C-a = 81019.2 I-0.68 + 845.2, we inverted Airborne V isible Infrared Imaging Spectrometer reflectance data collected in the Tiog a Pass region of the Sierra Nevada in California to determine algal concent ration. For the 5.5-km(2) region imaged, the mean algal concentration was 1 ,306 cells ml(-1), the standard deviation was 1,740 cells ml(-1), and the c oefficient of variation was 1.33. The retrieved spatial distribution was co nsistent with observations made in the field. From the spatial estimates of algal concentration, we calculated a total imaged algal biomass of 16.55 k g for the 0.495-km(2) snow-covered area, which gave an areal biomass concen tration of 0.033 g/m(2).