Bio-optical Properties of Coastal Waters in the Eastern English Channel

Abstract Strong tidal currents, shallow water and numerous freshwater inputs characterize the coastal waters of the eastern English Channel. These case 2 waters were investigated through an intensive sampling effort in 2000 aiming to study the distribution and variability of the Chromophoric Dissolved Organic Matter (CDOM), Non-Algal Particles (NAP) and phytoplankton absorption at the mesoscale. Four cruises were carried out in February, March, May and July and more than 80 stations each cruise were sampled for hydrographical, chemical and bio-optical analyses. Results showed two distinct situations, the winter period characterized by the strong dominance of CDOM absorption over the particulate matter, and the spring–summer period when phytoplankton and CDOM represented the same contribution. Meteorology was the main factor driving the bio-optical properties of the water column in winter whereas in spring–summer the biological activity seemed to be the more active driving force. The algal community composition in term of dominant cell size and, therefore pigment packaging, is the main factor driving the phytoplankton specific absorption in the water column. Photoprotective pigments did not significantly influence algal absorption, due to turbid and highly mixed water masses. This feature also explained the bio-optical homogeneity found along the water column. On the mesoscale, distinct bio-optical provinces were defined in relation with the observed bio-hydrographical variability.

[1]  R. W. Austin,et al.  Ocean Optics Protocols for Satellite Ocean Color Sensor Validation , 2013 .

[2]  Dennis A. Hansell,et al.  Global distribution and dynamics of colored dissolved and detrital organic materials , 2002 .

[3]  Lisa R. Moore,et al.  Determination of spectral absorption coefficients of particles, dissolved material and phytoplankton for discrete water samples , 2000 .

[4]  D. Keith,et al.  Spatial and Temporal Distribution of Coloured Dissolved Organic Matter (CDOM) in Narragansett Bay, Rhode Island: Implications for Phytoplankton in Coastal Waters , 2002 .

[5]  M. Collins,et al.  Suspended particulate matter fluxes through the Straits of Dover, English Channel: observations and modelling , 2000 .

[6]  Dale A. Kiefer,et al.  In-vivo absorption properties of algal pigments , 1990, Defense, Security, and Sensing.

[7]  E. Davidson,et al.  What are the physical, chemical, and biological processes that control the formation and degradation of nonliving organic matter? , 1995 .

[8]  A. Shiomoto,et al.  Comparison of east and west chlorophyll a standing stock and oceanic habitat along the Transition Domain of the North Pacific , 2000 .

[9]  A. W. Morris,et al.  Bed stress induced sediment resuspension (SERE 88/89) , 1998 .

[10]  C. Brunet,et al.  Tidal and diel periodicities of size-fractionated phytoplankton pigment signatures at an offshore station in the southeastern English Channel , 2003 .

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

[12]  Dariusz Stramski,et al.  Light absorption by aquatic particles in the near‐infrared spectral region , 2002 .

[13]  P. Falkowski,et al.  Nitrogen- and irradiance-dependent variations of the maximum quantum yield of carbon fixation in eutrophic, mesotrophic and oligotrophic marine systems , 1996 .

[14]  C. Binding,et al.  The optical properties of mineral suspended particles: A review and synthesis , 2006 .

[15]  Robert A. Arnone,et al.  Watercolors in the Coastal Zone: What Can We See? , 2004 .

[16]  C. Gallegos,et al.  Temporal variability of optical properties in a shallow, eutrophic estuary: Seasonal and interannual variability , 2005 .

[17]  Stefan G. H. Simis,et al.  Remote sensing of the cyanobacterial pigment phycocyanin in turbid inland water , 2005 .

[18]  R. Bidigare,et al.  Accessory pigments versus chlorophyll a concentrations within the euphotic zone: A ubiquitous relationship , 2000 .

[19]  A. J. Bale,et al.  Aggregation and resuspension of suspended particulate matter at a seasonally stratified site in the southern North Sea: physical and biological controls , 1998 .

[20]  P. Kowalczuk.  Seasonal variability of yellow substance absorption in the surface layer of the Baltic Sea , 1999 .

[21]  M. Collins,et al.  Annual variations in suspended particulate matter within the Dover Strait , 1993 .

[22]  R. Zepp,et al.  Factors Influencing Photoreactions of Dissolved Organic Matter in a Coastal River of the Southeastern United States , 1998 .

[23]  Marcel Babin,et al.  Variations of light absorption by suspended particles with chlorophyll a concentration in oceanic (case 1) waters: Analysis and implications for bio-optical models , 1998 .

[24]  L. Tranvik.  Microbial transformation of labile dissolved organic matter into humic‐like matter in seawater , 1993 .

[25]  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 .

[26]  A. Weidemann,et al.  Quantifying absorption by aquatic particles: A multiple scattering correction for glass-fiber filters , 1993 .

[27]  M. Moline,et al.  Watercolors in the Coastal Zone , 2004 .

[28]  Stelvio Tassan,et al.  An alternative approach to absorption measurements of aquatic particles retained on filters , 1995 .

[29]  Jean-François Berthon,et al.  Investigation of the optical backscattering to scattering ratio of marine particles in relation to their biogeochemical composition in the eastern English Channel and southern North Sea , 2007 .

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

[31]  H. Bouman,et al.  Bio-optical properties of the subtropical North Atlantic. I. Vertical variability , 2000 .

[32]  R. Casotti,et al.  Mesoscale features of phytoplankton and planktonic bacteria in a coastal area as induced by external water masses , 2000 .

[33]  L. Prieur,et al.  Analysis of variations in ocean color1 , 1977 .

[34]  J. Dupont,et al.  Diatoms as particulate tracers in the water column in the eastern English Channel , 1994 .

[35]  J. R. Nelson,et al.  Particulate and dissolved spectral absorption on the continental shelf of the southeastern United States , 1995 .

[36]  Y. Auger,et al.  Le fleuve cotier : Un phenomene hydrologique important en Manche orientale. Exemple du Pas-de-Calais , 1991 .

[37]  C. Gallegos,et al.  Partitioning spectral absorption in case 2 waters: discrimination of dissolved and particulate components. , 2002, Applied optics.

[38]  C. Brunet,et al.  In situ variations of the xanthophylls diatoxanthin and diadinoxanthin: photoadaptation and relationships with a hydrodynamical system in the eastern English Channel , 1993 .

[39]  T. Fisher,et al.  Production of chromophoric dissolved organic matter fluorescence in marine and estuarine environments: an investigation into the role of phytoplankton , 2002 .

[40]  K. Carder,et al.  Marine humic and fulvic acids: Their effects on remote sensing of ocean chlorophyll , 1989 .

[41]  Christophe Brunet,et al.  Hydrography and Phytoplankton Biomass in the Eastern English Channel in Spring 1992 , 1996 .

[42]  H. Sosik,et al.  Light absorption by phytoplankton, photosynthetic pigments and detritus in the California Current System , 1995 .

[43]  H. Claustre,et al.  Determination of chlorophylls and carotenoids of marine phytoplankton: separation of chlorophyll a from divinylchlorophyll a and zeaxanthin from lutein , 1996 .

[44]  Marcel Babin,et al.  Light absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM), in the St. Lawrence Estuary (Case 2 waters) , 1997 .

[45]  Dariusz Stramski,et al.  Variations in the light absorption coefficients of phytoplankton, nonalgal particles, and dissolved organic matter in coastal waters around Europe , 2003 .

[46]  B. Sautour,et al.  Annual variations of phytoplankton biomass in the Eastern English Channel: comparison by pigment signatures and microscopic counts , 2000 .

[47]  M Sydor,et al.  Effect of suspended particulate and dissolved organic matter on remote sensing of coastal and riverine waters. , 1997, Applied optics.

[48]  P. Kaiser.  The role of non-living organic matter in the earth's carbon cycle: Zepp, R.G. & Sonntag, C.H. (Eds) Vol. 1 (15.5×23.5 cm), 342 pages. John Wiley & Sons , 1995 .

[49]  Stelvio Tassan,et al.  A METHOD USING CHEMICAL OXIDATION TO REMOVE LIGHT ABSORPTION BY PHYTOPLANKTON PIGMENTS , 1999 .

[50]  Christophe Brunet,et al.  Phytoplankton Dynamics During the Spring Bloom in the South-eastern English Channel , 1996 .

[51]  Robert F. Chen,et al.  Chromophoric dissolved organic matter (CDOM) source characterization in the Louisiana Bight , 2004 .

[52]  H. Claustre,et al.  Variability in the chlorophyll‐specific absorption coefficients of natural phytoplankton: Analysis and parameterization , 1995 .

[53]  G. Billen,et al.  Microbial degradation of Phaeocystis material in the water column , 1994 .

[54]  G. Ferrari,et al.  Geo-chemical and optical characterizations of suspended matter in European coastal waters , 2003 .

[55]  C. Stedmon,et al.  Optical properties and signatures of chromophoric dissolved organic matter (CDOM) in Danish coastal waters , 2000 .

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

[57]  Timothy J. Smyth,et al.  Inherent optical properties of the Irish Sea and their effect on satellite primary production algorithms , 2005 .

[58]  W. Gieskes,et al.  Regional and seasonal differences in light absorption by yellow substance in the Southern Bight of the North Sea , 1999 .

[59]  J. Cleveland.  Regional models for phytoplankton absorption as a function of chlorophyll a concentration , 1995 .

[60]  D. Siegel,et al.  Seasonal dynamics of colored dissolved material in the Sargasso Sea , 1998 .

[61]  L. Artigas,et al.  Coastal bacterial viability and production in the eastern English Channel: A case study during a Phaeocystis globosa bloom , 2006 .