KNAW Repository

Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

Kromkamp, J.C. and Morris, E.P. and Forster, R.M. and Honeywill, C. and Hagerthey, S. and Paterson, D.M. (2006) Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence. Estuaries and Coasts, 29, 183-196. ISSN 1559-2723.

[img]PDF - Published Version
Restricted to KNAW only

369Kb

Official URL: http://dx.doi.org/10.1007/BF02781988

Abstract

Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two approaches were applied in 4 European estuaries with different sediment characteristics. At each site, paired replicate measurements of hyperspectral reflectance, chlorophyll fluorescence (after 15 min dark adaptation, Fo15), sediment water content, and chlorophyll a concentrations were taken (including breakdown products: [chl a + phaeo]). Sediments were further characterized by grain size and organic content analysis. The spectral signatures of tidal flats dominated by benthic microalgae, mainly diatoms, could be easily distinguished from sites dominated by macrophytes; we present a 3 waveband algorithm that can be used to detect the presence of macrophytes. The normalized difference vegetation index (NDVI) was found to be most strongly correlated to sediment [chl a + phaeo], except for the predominantly sandy Sylt stations. Fo15 was also significantly correlated to sediment [chl a + phaeo] in all but one grid (Sylt grid A). Our results suggest that the functional relationships (i.e., the slopes) between NDVI or fluorescence and [chl a + phaeo] were not significantly different in the muddier grids, although the intercepts could differ significantly, especially for Fo15. This suggests a mismatch of the optical depth seen by the reflectometer or fluorometer and the depth sampled for pigment analysis. NDVI appears to be a robust proxy for sediment [chl a + phaeo] and can be used to quantify MPB biomass in muddy sediments of mid latitude estuaries

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:12145
Deposited On:23 Nov 2011 01:00
Last Modified:31 Mar 2014 10:40

Repository Staff Only: item control page