Variations in the spectral values of specific absorption of phytoplankton

Sathyendranath, Shubha; Lazzara, Luigi; Prieur, Louis

doi:10.4319/lo.1987.32.2.0403

Cited by 275 publications

(206 citation statements)

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“…The flattening in the UV waveband likely depends on the shape and size of cells, but also on the composition and internal distribution of the UV absorbing compounds within the cells (as seen for pigments in the visible range; e.g. Sathyendranath et al 1987). A nonhomogenous distribution of MAAs in the cells, targeted around UV-sensitive organelles for increased protection efficiency, has been suggested by Neale et al (1998) and could be a major cause of this UV flattening.…”

Section: Discussionmentioning

confidence: 99%

Packaging of mycosporine-like amino acids in dinoflagellates

Laurion¹,

Blouin²,

Roy³

2004

Mar. Ecol. Prog. Ser.

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Synthesis of mycosporine-like amino acids (MAAs) can significantly protect phytoplankton cells against damaging ultraviolet (UV) radiation, depending on the concentration, type and cellular distribution of these UV sunscreens. We addressed the hypothesis that MAAs are concentrated around UV-sensitive organelles for improved efficiency, thereby increasing their 'package effect'. This was investigated for 2 species of MAA-producing dinoflagellates, with comparative analyses of a MAA-free diatom. Spectral absorbance of dinoflagellates suspended in their growth medium was relatively small throughout the MAA-absorbing region despite high concentrations of these compounds (determined by HPLC), suggesting that MAAs are highly packaged in intact cells. The measured in vivo absorbance of suspended and filtered phytoplankton cells revealed an extracellular release of water-soluble MAAs during freezing. The release of MAAs upon thawing enabled the calculation of an MAA packaging index based on the comparison between absorption characteristics before (MAAs inside cells in suspension) and after freezing (MAAs released from cells on thawed filters). Additionally, MAA packaging was evaluated from the reconstruction of absorption spectra from the individual MAA concentration. Consistent with our hypothesis, the results showed that UV absorption was up to 80% lower in the intact cells relative to the MAAs dissolved in solution. These results imply a high degree of MAA packaging in these dinoflagellates, that may increase the protection efficiency for specific cellular targets. KEY WORDS: Package effect · Photoprotection · MAAs · UV-absorbing compounds · Bio-optics · Alexandrium tamarense Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 279: [297][298][299][300][301][302][303] 2004 Pigment packaging has a major influence on the light harvesting efficiency of algal cells (Kirk 1994 and references therein). The absorption efficiency of phytoplankton is a non-linear function of pigment concentration, thylakoid arrangement and cell size (Berner et al. 1989, Nelson et al. 1993. A similar packaging effect for UV sunscreens could be of importance to MAAproducing phytoplankton. For UV sunscreens however, packaging can be viewed as effectiveness, since with equal investments, a large organism would benefit more than a small one. The bio-optical model developed by Garcia-Pichel (1994) indicates that MAAs should only be marginally effective at reducing UV radiation due to the short pathlength characteristic of relatively small phytoplankton cells (assuming a homogeneous cytoplasmic distribution of MAAs). However, the localization of MAAs around UV-sensitive organelles (packaged MAAs) might increase their efficiency, although this has not yet been assessed. MAA packaging has been suggested previously for the colonial prymnesiophyte Phaeocystis antarctica (Davidson & Marchant 1994, Moisan & Mitchell 2001. However, MAA concentrations observed in colonial prymnesiophytes appeared too h...

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Section: Discussionmentioning

confidence: 99%

Packaging of mycosporine-like amino acids in dinoflagellates

Laurion¹,

Blouin²,

Roy³

2004

Mar. Ecol. Prog. Ser.

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“…Probable cell-size distribution in this study As mentioned, the flattening effect is affected by cell-size (More1 & Bricaud 1981, Sathyendranath et al 1987, Cleveland 1995. Although cell-sizes were not measured in our study, a plausible ranking of cell-size among groups can be made based on the information about algal composition provided 'by the HPLC analysis (i.e.…”

Section: Factors Influencing the Absorption Coefficientmentioning

confidence: 70%

“…The optical density or absorbance (D) was recorded between 350 and 750 nm. The value measured at 750 nm was subtracted from the rest of the spectrum, assuming that this optical density was due to non-pigmented substances and that its effect was spectrally neutral (Sathyendranath et al 1987, Bricaud & Stramski 1990.…”

Section: Methodsmentioning

confidence: 99%

“…absorption increases linearly with pigment concentration. However, when dealing with in vivo absorption by phytoplankton cells, this linear relationship is affected by 2 additional factors: pigment composition and the flattening effect (Sathyendranath et al 1987). Since the total phytoplankton absorption at a given wavelength 1s the sum of the contributions from each of the pigments to absorption at that wavelength, changes in pigment composition will certainly affect the relationship between absorption and chl a concentration in the case of the 'single-pigment' method.…”

Section: Factors Influencing the Absorption Coefficientmentioning

confidence: 99%

“…The shape of the absorption spectrum of a phytoplankton population is determined mainly by its pigment composition and by the flattening effect of particles in suspension (Duysens 1956, Kirk 1983, Sathyendranath et al 1987. Changes in species composition and in physiological conditions affect the absorption properties of phytoplankton, and consequently Kd(h), since the latter depends on the absorption coefficient of phytoplankton, aph(h) (m-') (Kirk 1983, Smith et al 1989).…”

Section: Introductionmentioning

confidence: 99%

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Absorption coefficient of phytoplankton:regional variations in the North Atlantic

Lutz¹,

Sathyendranath²,

Head³

1996

Mar. Ecol. Prog. Ser.

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The effect of major pigments on the absorption characteristics of phytoplankton were evaluated by comparing the in vjvo absorption spectra of phytoplankton with pigment data obtained using high-performance liqu~d chromatography (HPLC) for samples of phytoplankton collected in the northwestern Atlantic Ocean, during spring. Four groups of spectra having distinct absorption characteristics and well-defined regional distributions were identified. The result of using general parameters to estimate the absorption coefficient of phytoplankton from any region, the 'general approach', was compared with the result of using specific parameters for each region, or the 'regional approach' Two methods of estlrnating the absorption coefficient were tested for each approach. These were: a 'slnglepigment' method (Prieur & Sathyendranath 1981, Limnol Oceanogr 26:671-689), and a 'multi-pigment' method (Hoepffner & Sathyendranath 1991, Mar Ecol Prog Ser 73:ll-23). It was shown that the regional approach performed better (<10% average error) than the general approach (~2 0 % average error). Nevertheless, the results given by the general approach could be acceptable for some applications. The multi-pigment and the single-pigment methods performed equally well in the context of the reglonal approach, whereas in the general approach, the s~ngle-pigment method gave better results than the multi-pigment method. Overall, it appears that part~tioning the oceans into regions according to their absorption characteristics should improve regional models of light transmission and the algorithms for detection of pigments by remote sensing.

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Phenology of particle size distributions and primary productivity in the North Pacific subtropical gyre (Station ALOHA)

et al. 2015

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The particle size distribution (PSD) is a critical aspect of the oceanic ecosystem. Local variability in the PSD can be indicative of shifts in microbial community structure and reveal patterns in cell growth and loss. The PSD also plays a central role in particle export by influencing settling speed. Satellite‐based models of primary productivity (PP) often rely on aspects of photophysiology that are directly related to community size structure. In an effort to better understand how variability in particle size relates to PP in an oligotrophic ecosystem, we collected laser diffraction‐based depth profiles of the PSD and pigment‐based classifications of phytoplankton functional types (PFTs) on an approximately monthly basis at the Hawaii Ocean Time‐series Station ALOHA, in the North Pacific subtropical gyre. We found a relatively stable PSD in the upper water column. However, clear seasonality is apparent in the vertical distribution of distinct particle size classes. Neither laser diffraction‐based estimations of relative particle size nor pigment‐based PFTs was found to be significantly related to the rate of 14C‐based PP in the light‐saturated upper euphotic zone. This finding indicates that satellite retrievals of particle size, based on particle scattering or ocean color would not improve parameterizations of present‐day bio‐optical PP models for this region. However, at depths of 100–125 m where irradiance exerts strong control on PP, we do observe a significant linear relationship between PP and the estimated carbon content of 2–20 μm particles.

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Variations in the spectral values of specific absorption of phytoplankton

Cited by 275 publications

References 19 publications

Packaging of mycosporine-like amino acids in dinoflagellates

Packaging of mycosporine-like amino acids in dinoflagellates

Absorption coefficient of phytoplankton:regional variations in the North Atlantic

Phenology of particle size distributions and primary productivity in the North Pacific subtropical gyre (Station ALOHA)

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