TY - JOUR
T1 - Light Absorption by Suspended Particles in the Red Sea
T2 - Effect of Phytoplankton Community Size Structure and Pigment Composition
AU - Kheireddine, Malika
AU - Ouhssain, Mustapha
AU - Organelli, Emanuele
AU - Bricaud, Annick
AU - Jones, Burton H.
N1 - Funding Information:
The authors express their gratitude to the scientists, officers, and crews of the research vessel Thuwal and also the Coastal and Marine Resources Core Lab for logistical support and assistance onboard during the fieldwork. U. Langner is cordially thanked for plotting the map of the Red Sea, L. Solabarrieta and J. Otoadese for their advices and discussions on the results presented here and for reading the manuscript. Alison Chase and the anonymous reviewer are warmly thanked for the constructive comments on a previous version of the manuscript. This study is funded by the King Abdullah University of Science and Technology (KAUST), Kingdom of Saudi Arabia. The data presented in this study are available from the authors upon request (malika.kheireddine@kaust. edu.sa) and are also archived in https://drive.google.com/open?id5 0ByAL0hQpcGGPZmItRzh4eXNVdkk.
Publisher Copyright:
© 2018. American Geophysical Union. All Rights Reserved.
PY - 2018/2
Y1 - 2018/2
N2 - The light absorption properties of phytoplankton (aph(λ)) and nonalgal particles (anap(λ)) associated with phytoplankton pigments were analyzed across the Red Sea, in the upper 200 m depth, between October 2014 and August 2016. The contribution by nonalgal particles to the total particulate light absorption (aph(λ) + anap(λ)) was highly variable (23 ± 17% at 440 nm) and no relationship between anap(440) and chlorophyll a concentration, [TChl a], was observed. Phytoplankton-specific phytoplankton absorption coefficients at 440 and 676 nm for a given [TChl a], aph*(440), and a*ph (676) were slightly higher than those derived from average relationships for open ocean waters within the surface layer as well as along the water column. Variations in the concentration of photosynthetic and photoprotective pigments were noticeable by changes in phytoplankton community size structure as well as in a*ph(λ). This study revealed that a higher proportion of picophytoplankton and an increase in photoprotective pigments (mainly driven by zeaxanthin) tended to be responsible for the higher a*ph(λ) values found in the Red Sea as compared to other oligotrophic regions with similar [TChl a]. Understanding this variability across the Red Sea may help improve the accuracy of biogeochemical parameters, such as [TChl a], derived from in situ measurements and ocean color remote sensing at a regional scale.
AB - The light absorption properties of phytoplankton (aph(λ)) and nonalgal particles (anap(λ)) associated with phytoplankton pigments were analyzed across the Red Sea, in the upper 200 m depth, between October 2014 and August 2016. The contribution by nonalgal particles to the total particulate light absorption (aph(λ) + anap(λ)) was highly variable (23 ± 17% at 440 nm) and no relationship between anap(440) and chlorophyll a concentration, [TChl a], was observed. Phytoplankton-specific phytoplankton absorption coefficients at 440 and 676 nm for a given [TChl a], aph*(440), and a*ph (676) were slightly higher than those derived from average relationships for open ocean waters within the surface layer as well as along the water column. Variations in the concentration of photosynthetic and photoprotective pigments were noticeable by changes in phytoplankton community size structure as well as in a*ph(λ). This study revealed that a higher proportion of picophytoplankton and an increase in photoprotective pigments (mainly driven by zeaxanthin) tended to be responsible for the higher a*ph(λ) values found in the Red Sea as compared to other oligotrophic regions with similar [TChl a]. Understanding this variability across the Red Sea may help improve the accuracy of biogeochemical parameters, such as [TChl a], derived from in situ measurements and ocean color remote sensing at a regional scale.
KW - Red Sea
KW - phytoplankton absorption
KW - phytoplankton size
KW - pigment composition
UR - http://www.scopus.com/inward/record.url?scp=85041284010&partnerID=8YFLogxK
U2 - 10.1002/2017JC013279
DO - 10.1002/2017JC013279
M3 - Article
AN - SCOPUS:85041284010
VL - 123
SP - 902
EP - 921
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 2
ER -