Mer Molécules Santé (MMS) – EA 21 60, Université de Nantes, BP 92208, Nantes Cedex 44322, France
Littoral Environnement et Sociétés (LIENSs) – UMR 7266, CNRS/Université de La Rochelle, Institut du Littoral et de l’Environnement, 2 rue Olympe de Gouges, La Rochelle 17000, France
Takuvik– UMI 3376, CNRS/Université Laval, Département de Biologie, Pavillon Alexandre Vachon, 1045 avenue de la Médecine, Québec, QC G1V 0A6, Canada
: Received: 28 September 2016 / Approved: 28 September 2016 / Online: 28 September 2016 (11:43:29 CEST)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
How to cite:
Méléder, V.; Lavaud, J.; Barnett, A.; Jesus, B.; Barillé, L. Microphytobenthos Primary Production Estimated by Hyperspectral Reflectance. Preprints2016, 2016090113 (doi: 10.20944/preprints201609.0113.v1).
Méléder, V.; Lavaud, J.; Barnett, A.; Jesus, B.; Barillé, L. Microphytobenthos Primary Production Estimated by Hyperspectral Reflectance. Preprints 2016, 2016090113 (doi: 10.20944/preprints201609.0113.v1).
Monitoring photosynthesis is a great challenge to improve our knowledge of plant productivity at the ecosystem level, which may be achieved using remote-sensing techniques with synoptic abilities. The main objective of the current study is to take up this challenge for microphytobenthos (MPB) primary production in intertidal mudflats. This was achieved by coupling hyperspectral radiometry (reflectance, ρ and second derivative, δδ) and PAM-fluorometry (non-sequential light curve, NSLC) measurements. The later allowed the estimation of the primary production via the light use efficiency (LUE) and the electron transport rate (ETR) whereas ρ allowed to estimate pigment composition and optical absorption cross-section (a*). Five MPB species representative of the main growth forms: epipelic (benthic motile), epipsammic (benthic motile and non motile) and thycoplanktonic (temporarily resuspended in the water column) were lighted at increasing light intensity from dark to 1950 µmol photons.m-2.s-1. After spectral measurements, a* was retrieved using a radiative transfer model and several radiometric indices were tested for their capacity to predict LUE and ETR. The spectral estimation of these two photosynthetic variables was subsequently compared to the values estimated by PAM-fluorometry. Results showed that different responses related to the xanthophyll cycle (de-epoxydation state) were observed for the three growth-forms with increasing light levels. However, a single relationship with radiometric index was not affected by species/growth-forms, i.e. δδ496/508, called the MPBLUE index to predict LUE and ETR. This index has the potential to be applied to air borne hyperspectral imagery for large-scale assessment of MPB production.