A three component classification of phytoplankton absorption spectra: Application to ocean-color data

A method is presented to identify absorption characteristics of three optically-distinct phytoplankton classes from a suite of measurements of total phytoplankton absorption coefficient and chlorophyll-a concentration by successive application of the two-population absorption model of Sathyendranath et al. (2001) and Devred et al. (2006a). The total phytoplankton absorption coefficient at multiple wavelengths is expressed as the weighted sum of the absorption coefficients of each class at those wavelengths. The resultant system of equations is solved under some constraints to derive the fraction of each class present in any given sample of seawater, given the spectrum of total phytoplankton absorption coefficient. When applied to a large database, the results compare well with phytoplankton size-classes derived from pigment composition, so that we can assume that the three phytoplankton classes derived from absorption coefficients are representative of the pico-, nano- and microphytoplankton size classes. A modification is proposed to the pigment-based phytoplankton size classification of Uitz et al. (2006) to account for the effect of fucoxanthin associated with nanophytoplankton. Comparison between satellite and in situ data demonstrates the potential of satellite ocean-color data to yield the distribution of phytoplankton size classes from space. The algorithm is applied to phytoplankton absorption coefficients derived from remotely-sensed reflectance values collected by SeaWiFS over the Northwest Atlantic in 2007. Monthly composites for April, August and November, representative of Spring, Summer and Fall, give synoptic views of the phytoplankton community structure: a Spring bloom dominated by microphytoplankton is followed by a second, less intense, bloom in the Fall dominated by nanophytoplankton. Picophytoplankton are dominant in the study area in Summer.

[1]  N. B. Hargreaves,et al.  Physical factors controlling summer distribution of chlorophyll a off southwestern Nova Scotia1 , 1984 .

[2]  L. Duysens,et al.  The flattening of the absorption spectrum of suspensions, as compared to that of solutions. , 1956, Biochimica et biophysica acta.

[3]  Annick Bricaud,et al.  Estimation of new primary production in the Benguela upwelling area, using ENVISAT satellite data and a model dependent on the phytoplankton community size structure , 2008 .

[4]  A. Bricaud,et al.  Theoretical results concerning light absorption in a discrete medium, and application to specific absorption of phytoplankton , 1981 .

[5]  J. Cullen,et al.  A semi-analytical model of the influence of phytoplankton community structure on the relationship between light attenuation and ocean color , 1999 .

[6]  David A. Siegel,et al.  Retrieval of the particle size distribution from satellite ocean color observations , 2009 .

[7]  S. Sathyendranath,et al.  A three-component model of phytoplankton size class for the Atlantic Ocean , 2010 .

[8]  T. Parsons,et al.  ENVIRONMENTAL CONTROL OF PHYTOPLANKTON CELL SIZE , 1973 .

[9]  W. Gregg.  Reports of the International Ocean-Colour Coordinating Group , 2007 .

[10]  Andrew J. Watson,et al.  Ecosystem dynamics based on plankton functional types for global ocean biogeochemistry models , 2005 .

[11]  B. Mitchell,et al.  Determination of Absorption and Fluorescence Excitation Spectra for Phytoplankton , 1984 .

[12]  François-Marie Bréon,et al.  Remote sensing of phytoplankton groups in case 1 waters from global SeaWiFS imagery , 2005 .

[13]  S. Sathyendranath,et al.  Effect of pigment composition on absorption properties of phytoplankton , 1991 .

[14]  Hervé Claustre,et al.  Phytoplankton pigment distribution in relation to upper thermocline circulation in the eastern Mediterranean Sea during winter , 2001 .

[15]  T. Smayda.  The suspension and sinking of phytoplankton in the sea , 1970 .

[16]  S. W. Jeffrey,et al.  Introduction to marine phytoplankton and their pigment signatures , 1997 .

[17]  Decadal changes in ecological provinces of the Northwest Atlantic Ocean revealed by satellite observations , 2009 .

[18]  H. Claustre,et al.  Vertical distribution of phytoplankton communities in open ocean: An assessment based on surface chlorophyll , 2006 .

[19]  A. Longhurst.  Ecological Geography of the Sea , 1998 .

[20]  J. Ras,et al.  Validation of MERIS reflectance and chlorophyll during the BENCAL cruise October 2002: preliminary validation of new demonstration products for phytoplankton functional types and photosynthetic parameters , 2007 .

[21]  S. Sathyendranath,et al.  Absorption coefficient of phytoplankton: regional variations in the North Atlantic , 1996 .

[22]  L. Bolis,et al.  Marine Phytoplankton and Productivity , 1984 .

[23]  Trevor Platt,et al.  Remote sensing of phytoplankton functional types , 2008 .

[24]  Julia Uitz,et al.  A phytoplankton class-specific primary production model applied to the Kerguelen Islands region (Southern Ocean) , 2009 .

[25]  Stéphane Maritorena,et al.  Optimization of a semianalytical ocean color model for global-scale applications. , 2002, Applied optics.

[26]  William K. W. Li,et al.  Coherent assembly of phytoplankton communities in diverse temperate ocean ecosystems , 2006, Proceedings of the Royal Society B: Biological Sciences.

[27]  John J. Cullen,et al.  Assessment of the relationships between dominant cell size in natural phytoplankton communities and the spectral shape of the absorption coefficient , 2002 .

[28]  George A. Jackson,et al.  Effects of phytoplankton community on production, size, and export of large aggregates: A world‐ocean analysis , 2009 .

[29]  Tiit Kutser,et al.  Monitoring cyanobacterial blooms by satellite remote sensing , 2006 .

[30]  T. Platt,et al.  Discrimination of diatoms from other phytoplankton using ocean-colour data , 2004 .

[31]  S. Wright,et al.  Phytoplankton Pigments in Oceanography: Guidelines to Modern Methods , 1997 .

[32]  T Platt,et al.  Ocean-color model incorporating transspectral processes. , 1998, Applied optics.

[33]  S. Sathyendranath,et al.  Bio-optical characteristics of coastal waters: Absorption spectra of phytoplankton and pigment distribution in the western North Atlantic , 1992 .

[34]  Williamk . W. Li.  From cytometry to macroecology: a quarter century quest in microbial oceanography , 2009 .

[35]  Satoru Taguchi,et al.  Variability in chlorophyll a specific absorption coefficient in marine phytoplankton as a function of cell size and irradiance , 2002 .

[36]  P. J. Werdell,et al.  An improved in-situ bio-optical data set for ocean color algorithm development and satellite data product validation , 2005 .

[37]  J. Burrows,et al.  Quantitative observation of cyanobacteria and diatoms from space using PhytoDOAS on SCIAMACHY data , 2008 .

[38]  W. Rogers.  Quantile regression standard errors , 1993 .

[39]  L. Legendre,et al.  From Individual Plankton Cells To Pelagic Marine Ecosystems And To Global Biogeochemical Cycles , 1991 .

[40]  Trevor Platt,et al.  Remote sensing of ocean colour: Towards algorithms for retrieval of pigment composition , 2005 .

[41]  S. Thiria,et al.  Retrieval of pigment concentrations and size structure of algal populations from their absorption spectra using multilayered perceptrons. , 2007, Applied optics.

[42]  T. Platt,et al.  Estimation of the photosynthetic action spectrum: implication for primary production models , 1997 .

[43]  T. Platt,et al.  Delineation of ecological provinces using ocean colour radiometry , 2007 .

[44]  Alan Weidemann,et al.  Phytoplankton spectral absorption as influenced by community size structure and pigment composition , 2003 .

[45]  E. Carpenter,et al.  Detecting Trichodesmium blooms in SeaWiFS imagery , 2001 .

[46]  T. Platt,et al.  Ecological indicators for the pelagic zone of the ocean from remote sensing , 2008 .

[47]  C. Yentsch.  MEASUREMENT OF VISIBLE LIGHT ABSORPTION BY PARTICULATE MATTER IN THE OCEAN1 , 1962 .

[48]  Annick Bricaud,et al.  Retrievals of a size parameter for phytoplankton and spectral light absorption by colored detrital matter from water‐leaving radiances at SeaWiFS channels in a continental shelf region off Brazil , 2006 .

[49]  Trevor Platt,et al.  Estimation of phytoplankton loss rate by remote sensing , 2008 .

[50]  H. Bouman,et al.  Physical forcing and phytoplankton distributions , 2005 .

[51]  Jim Aiken,et al.  An absorption model to determine phytoplankton size classes from satellite ocean colour , 2008 .

[52]  E. Fry,et al.  Absorption spectrum (380-700 nm) of pure water. II. Integrating cavity measurements. , 1997, Applied optics.

[53]  Trevor Platt,et al.  A two‐component model of phytoplankton absorption in the open ocean: Theory and applications , 2006 .

[54]  G. Kleppel.  On the diets of calanoid copepods , 1993 .

[55]  T. Platt,et al.  Analytic model of ocean color. , 1997, Applied optics.

[56]  S. W. Jeffrey,et al.  PHOTOSYNTHETIC PIGMENTS IN FIFTY‐ONE SPECIES OF MARINE DIATOMS 1 , 1988 .

[57]  Annick Bricaud,et al.  Natural variability of phytoplanktonic absorption in oceanic waters: Influence of the size structure of algal populations , 2004 .

[58]  T. Platt,et al.  Remote sensing of phytoplankton pigments: A comparison of empirical and theoretical approaches , 2001 .

[59]  H. Claustre,et al.  The Fourth SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-4) , 2009 .

[60]  Shubha Sathyendranath,et al.  Variations in the spectral values of specific absorption of phytoplankton , 1987 .

[61]  Hervé Claustre,et al.  The trophic status of various oceanic provinces as revealed by phytoplankton pigment signatures , 1994 .

[62]  S. W. Jeffrey,et al.  CHLOROPLAST PIGMENT PATTERNS IN DINOFLAGELLATES 1 , 1975 .