Our research over the last 5 years indicates that the successful transformation of ocean color imagery into maps of bio-optical properties will require continued development and testing of algorithms. In particular improvements in the accuracy of predicting from ocean color imagery the concentration of the bio-optical components of sea as well as the rate of photosynthesis will require progress in at least three areas: (1) we must improve mathematical models of the growth and physiological acclimation of phytoplankton; (2) we must better understand the sources of variability in the absorption and backscattering properties of phytoplankton and associated microparticles; and (3) we must better understand how the radiance distribution just below the sea surface varies as a function sun and sky conditions and inherent optical properties

Kiefer, Dale A.

Stramski, Dariusz

English

NASA Technical Reports Server

/vRs#/c z ¢'7- 112561 L/f W-357 
Final Technical Report for the SeaWiFS Project:
ANALYSIS OF PHOTOSYNTHETIC RATE AND BIO-OPTICAL
COMPONENTS FROM OCEAN COLOR IMAGERY
submitted to:
Janet W. Campbell, Manager
Ocean Biology/Biogeochemistry Program
MTPE/Code YS
NASA HQ
Washington, D.C. 20546
jcampbel @mail.hq.nasa.gov
fax: 202-358-3098
//A //?
7;;I3 -+ J - ,-/_
Jlc'l? 
O 8 s
by
Dale A. Kiefer (Principal Investigator)
Department of Biological Sciences
University of Southern California
University Park
Los Angeles, CA 90089-0371
& Dariusz Stramski (Co-Investigator)
Abstract
Our research over the last 5 years indicates that the successful transformation of ocean color
imagery into maps of bio-optical properties will require continued development and testing of
algorithms. In particular improvements in the accuracy of predicting from ocean color image_" the
concentration of the bio-optical components of sea as well as the rate of photosynthesis will
require progress in at least three areas:
1. We must improve mathematical models of the growth and physiological acclimation of
phytoplankton.
2. We must better understand the sources of variability in the absorption and backscattering
properties of phytoplankton and associated microparticles.
3. We must better understand how the radiance distribution just below the sea surface varies as a
function sun and sky conditions and inherent optical properties.
As members of the SeaWifs Team, we have made contributions in all three areas. The work we
conducted lead to the development and testing of both the USC Photosynthesis Algorithm and our
Components Algorithm, which provides estimates of 3 inherent optical properties.
The USC Photosynthesis Algorithm was among the top performers in the 1st Round Robin
Exercise. This algorithm is distinctly different from those proposed by other workers (e.g. Platt
and Sathyendranath 1988, Platt et al. 1991, Morel 1988, Morel 1991) because it includes a
mechanistic description of the variability in the cellular ratio of carbon to chlorophyll. Unlike most
of the other algorithms that have been proposed, the USC Productivity Algorithm recognizes the
importance of the depth of the surface mixed layer on both the vertical distribution of chlorophyll
and the physiological parameters of photosynthesis. This makes the algorithm particularly well
suited to coastal waters where mixed layer depths may vary.
The Components Algorithm that we have been developing is designed to retrieve from surface
reflectance the absorption coefficients of phytoplankton and detritus as well as the backscattering
corereflectance: the absorption coefficient of phytoplankton, the absorption coefficient of colored
dissolved and particulate materials, and the backscattering coefficient of suspended particles. Our
https://ntrs.nasa.gov/search.jsp?R=19980201263 2020-06-16T00:10:06+00:00Z
algorithmsharesfeaturesin commonwith thoseproposedby Carderandhisco-workers(1994)
andRoeslerandPerry(1995);however,it alsocontainsseveraluniquefeatures.Wehave
comparedpredictionsof our preliminary,versionof theComponents Algorithm with bio-optical
measurements made in the Bermuda Atlantic Time Series (oligotrophic case 1 waters), and in the
Baltic Sea (mesotrophic case 2 waters). The results were promising but inconclusive. The
discrepancies between predicted values of the absorption coefficient and measured values may be
caused by: contributions to reflectance by Raman scattering, variations in the shape of the
absorption and backscattering coefficients of the components, variations in the shape of the
upwelling radiance field, and incorrect values for the absorption coefficient of water.
Accomplishments as SeaWiFS Team Members
As members of the SeaWiFS Science Team, our laboratory helped to advance knowledge of the
sources of variability of ocean color and how this variability is tied to marine photosynthesis.
Much of this work is described in 21 research papers that are listed below. Below we have listed
the tasks found in our 1993 proposal followed by our corresponding accomplishments during our
4 years of participation.
Photosynthetic Algorithm
1. We will assemble database for the independent and dependent variables of the USC
Photosynthesis Algorithm for the North Atlantic. The independent variables include surface
irradiance, surface temperature, surface chlorophyll a concentration, photopenod, and surface
concentrations of ammonia and nitrate. The dependent variables include the vertical distribution of
chlorophyll a concentration, downwelling irradiance (spectral and PAR) and primary production.
We have assembled databases for the North Atlantic, the Bermuda Bio-optical Time Series, and the
Baltic Sea.
2. We will grow in continuous culture marine phytoplankton over a matrix of irradiances,
temperatures, photoperiods, and rates of nutrient supply. For each steady-state condition we will
measure rates of growth and cellular absorption of irradiance.
We have completed the most detailed study of the bio-optical properties of phytoplankton cultures
to date. The studies focused on diel variabili_ and nutrient limitation. (Stramski and Reynolds,
1993; Stramski et al., 1995; and Reynolds et al., 1996;Reynolds, 1996.)
3. We will reformulate the phenomenological model as an algorithm to transform maps of surface
chlorophyll concentration obtained from the CZCS and SeaWifs into maps of the concentration of
chlorophyll, phytoplanktonic carbon, and daily photosynthetic rate.
The USC Photosynthesis algorithm has been coded with Mathematica, and has been described in a
NASA publication (Behrenfeld et al., 1996). In addition many of the formulations may be found
in Ondercin, Atkinson, and [(defer, 1995. The algorithm was among the top performers in
NASA's Round Robin 1 exercise, and calculations for Round Robin 2 have just been submitted.
At present we do not know whether the inaccuracies in prediction were caused by errors in
estimating the independent variables of the model or whether they were caused by inadequacies of
the formulations.
4. From our database we will map the concentration of chlorophyll, phytoplanktonic carbon, and
daily photosynthetic rate for selected months in the North Atlantic and compare predictions with
appropriate field measurements.
2
Wehaveproducedseasonalmapsof thebio-opticalpropertiesof theupperwatercolumnin the
northAtlantic. Thesemapswerepresentedat theBrookhavenMeetingof theSeaWiFS
Productivi_'Team.A manuscript describing this work is near completion.
Reflectance algorithm
1. We will assemble a database on spectral reflectance measured within the euphotic zone at
diverse oceanographic sites. This database will include all bio-optical measurements such as
chlorophyll concentration, downwelling spectral irradiance, the volume attenuation coefficient, and
particle and cell concentration that will constrain our reconstruction of the spectral reflectance.
We have assembled a bio-optical database for the Bermuda Time Series and the Baltic Sea, and
have begun testing algorithms used to solve for absorption and backscattering coefficients. The
analysis of the BATS data is in collaboration with Dr Dave Siegel of UCSB and the analysis of the
Baltic Sea is in collaboration with Nicolas Hoeppfner of the Joint Research Center, Ispra, Italy.
Both databases are of high quality and comprehensive.
2. We will apply a simple regression analysis to our database on the spectral absorption coefficient
of suspended particles, ap(_,), retrieving at least a phytoplankton and detrital components.
We tried unsuccessfully to obtain an analytical solution to a 3 component reflectance model. This
approach appears to be too sensitive to variations in spectral shape of the three components and to
errors in measurement.
3. We will program and test a component model of diffuse spectral reflectance in the upper ocean.
This model will be developed in a fashion similar to that described in Stramski and Kiefer (1991).
In collaboration with Curt Mobley we have published 2 papers on the effect of variations in the
taxonomic composition of the planktonic community upon the inherent and apparent optical
properties of sea water. The papers (Stramski and Mobley, 1997 a &b) will be soon appear in
Limnology and Oceanography.
4. We will continue to culture marine microorganisms in the laboratory that may be important
contributors to scattering and absorption in the sea. We will focus our attention on the optical
properties of detrital particles produced by the grazing of flagellates and ciliates. We will also
continue our study of the contribution by bacteria to absorption and scattering.
We have continued to measure the optical properties of marine particles produced in laboratory
cultures. This work includes studies on phytoplankton (Reynolds, 1996; Reynolds et al., 1997;
Stramski and Reynolds, 1993), detrital particles (Rosser and Berwald, 1994), and bacteria (Nagao
and Stramski, 1994).
5. We will attempt to adapt our reflectance model to an analysis of CZCS and SeaWifs imagery.
During the last year, we have inverted a 3 component version of the reflectance model and
compared predicted values of the concentration of chlorophyll a with measured values. In some
BATS profiles the agreement is very good and others it is unsatisfactory. The same can be said for
profiles from the Baltic Sea.
Publications Supported by our membership as NASA SeaWiFS Team
3
Members (1993-1997)
Behrenfeld, M. J., Esaias, W. E., Falkowski, P. G., Balch, B., Campbell, J. W., Iverson, R. L.,
Kiefer, D. A., Morel, A., & Yoder, J. A. (1994). Toward a Consensus Productivit-y Algorithm for
SeaWiFS: Summary_ report for 23-25 January 1994 Workshop (NASA Technical Report Series
No. 104566). NASA.
Berwald, J., Stramski, D., Kiefer, D., & Mobley, C. (1996). The effect of Raman scattering on
the asymptotic cosine in the ocean. In Ackelson (Ed.), Ocean Optics XII, Proc. Soc. Photo-Optical
Instrumentation Engineers, (pp. 6 pages). Halifax, Nova Scotia:
Berwald, J., Stramski, D., Mobley, C. B., & Kiefer, D. A. (1995). Influences of absorption and
scattering on vertical changes of the mean cosine for irradiance in natural waters. Limnol.
Oceangr., 40(6), 1347-1357.
Chamberlin, W. S., Morrow, J. H., & Kiefer, D. A. Patterns of variability in the spectral
absorption coefficients of suspended particles in oceanic waters No.
Cullen, J. J., Geider, R. J., Ishizaka, J., Kiefer, D. A., Marra, J., Sakshaug, E., & Raven, J. A.
(1993). Towards a general description of phytoplankton growth for biogeochemical models. In G.
T. Evans & M. J. R. Fasham (Eds.), Towards a Model of Ocean Biogeochemical Processes (pp.
153-176). Berlin: Springer-Verlag.
Stramski, D., Reynolds, R. A. (1993). Diel variations in the optical properties of a marine diatom.
Limnol. Oceanogr., 38, 1347-1364.
Jonasz, M., Fournier, G., & Stramski, D. (1997). Photometric immersion refractometry: a method
for determining the refractive index of marine microbial particles from beam attenuation. Applied
_, in press.
Kiefer, D. A. (1993). Modelling growth and light absorption in the marine diatom Skeletonema
costatum. In G. T. E. a. J. R. Fasham (Eds.), Towards a Model of Ocean Biogeochemical
Processes (pp. 93-118). Berlin: Springer-Verlag.
Kiefer, D. A. (1994). Light absorption, fluorescence, and photosynthesis: Skeletonema costatum
and field measurements. In R. W. Spinrad, K. L. Carder, & M. J. Perry (Eds.), Ocean Optics
(pp. 165-188). New York: Oxford Univ. Press.
Kiefer, D. A. (1996). An Environmental Model for Small Pelagics. In D. C. &. Kiefer (Ed.),
Workshop on the Coastal Pelagic Resources of the Upwelling Ecosystem of Northwest Africa:
Research and Predictions, (pp. pages 37). Casablanca, Morocco: FAO.
Kiefer, D. A., Atkinson, C. A., & Ondercin, D. (1994). A bit-optical mapping procedure for the
north Atlantic Ocean. In J. Jaffe (Ed.), Ocean Optics XII, Society of Photo-optical Instrumentation
Engineers, 2258 (pp. 163-173). Bergen, Norway: International Society for Optical Engineering
SPIE.
Mobley, C. D., & Stramski, D. (1997). Effects of Microbial Particles on Oceanic Optics:
Methodology for Radiative Transfer Modeling and Example Simulations. Limnology and
Occanography, in prcss.
Nagao, T. T. & Stramski, D. (1994). Optical properties of free-living, caroteniod-containing
4
heterotrophic bacteria isolate from the marine environmenL Special Topics Paper, University of
Southern California.
Ondercin, D., Atkinson, C. A., & Kiefer, D. A. (1995). The Distribution of Bioluminescence and
Chlorophyll During the Late Summer in the North Atlantic: Maps and a Predictive Model. Journal
of Geophysical Research, 100(C4), 67-690.
Reynolds, R. A., Stramski, D., & Kiefer, D. A. (1996). The Effect of nitrogen-limitation on the
absorption and scattering properties of the marine diatom Thalassiosira pseudonana. Limnology
and Oceanography, _, 39 pages.
Rosser, C. and Berwald, J. (1994). The responce os beam attenuation, absorption, and scattering
to the grazing of the protist, Uronema marina on heterotrophic bacteria. Special Topics Paper,
Univerisity of Southern California.
Sakshaug, E., Bricaud, A., Dandonneau, Y., Falkowski, P., Kiefer, D., Legendre, L., Morel,
A., Parslow, J., & Takahashi, M. (1996). Measurement of the Parameters of Photosynthesis:
Light Absorption and Quantum Yield of Photosynthesis Derived fro P-E Determinations No.
JGOFS Photosynthesis Measurements Task Team.
Stramski, D. (1994). Gas microbubbles: An assessment of their significance to light scattering in
quiescent seas. In J. Jaffe (Ed.), Ocean Optics XII, 2258. Bergen, Norway: SPIE-The
International Society for Optical Engineering.
Stramski, D., & Mobley, C. D. (1997). Effects of microbial particles on oceanic
optics: A database of single-particle optical properties. Limnology and Oceanography, (in press).
Stramski, D., & Sedlak, M. (1994). Application of dynamic light scattering to the study of small
marine particles. Applied Optics, 33(21), 4825-34.
Stramski, D., Shalapyonok, A., & Reynolds, R. A. (1995). Optical characterization of the oceanic
unicellular cyanbacterium Synechoccus grown under a day night cycle in natural irradiance. Jour
Geophysical Res, 100(C7), 13, 295-13307.
5


Analysis of Photosynthetic Rate and Bio-Optical Components from Ocean Color Imagery

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server