Abstract
Variability of the optical properties of the northern Gulf of California (Mexico) were analyzed for the first time based on six cruises performed from spring to summer (March to September) between 2008 and 2013. The changes observed in the absorption by three seawater components (phytoplankton, detritus and chromophoric dissolved organic matter or CDOM) were analyzed in relation to changes in bio-optical regions and composition of the phytoplankton community (determined based on phytoplankton pigments). Two regions with unique bio-optical characteristics were identified separated by a narrow transition zone: the Upper Gulf of California (UGC) and Northern Gulf of California (NGC). Despite the temporal changes in their spatial distribution they maintained particular characteristic. UGC is characterized by an average Chla of 1.78 mg/m3, the dominance of microphytoplankton (diatoms and dinoflagellates) and a stronger contribution of detritus to total light absorption. NGC is characterized by an average Chla of 0.7 mg/m3 and the predominance of picophytoplankton, characterized by the dominance of zeaxanthin (marker pigment for cyanobacteria) and/or chlorophyll b (marker pigment for green algae), along with a co-dominium by CDOM and phytoplankton to light absorption. Results indicate that Case II waters can be very different when evaluating the individual contribution by phytoplankton, detritus and CDOM to total light absorption what has to be considered for the selection of bio-optical models for each specific region what can also help to a better definition of the related uncertainties.
Highlights
The study of the optical properties of the ocean has raised increasing interest in the last decades, leading to the development of technological tools to estimate these properties through remote sensing [1] [2] [3]
Different when evaluating the individual contribution by phytoplankton, detritus and CDOM to total light absorption what has to be considered for the selection of bio-optical models for each specific region what can help to a better definition of the related uncertainties
This work makes a major contribution to the knowledge of the bio-optical properties in optically complex waters such as those to the north of the Gulf of California, a region characterized by a strong hydrodynamic reflected in a marked spatial and temporal variability of their bio-optical properties, including the composition of primary producers
Summary
The study of the optical properties of the ocean has raised increasing interest in the last decades, leading to the development of technological tools to estimate these properties through remote sensing [1] [2] [3]. These tools have been validated for Case-I waters [4], which do not represent the conditions of coastal areas characterized by being optically complex (Case II) and that concentrate the main economic and productive activities in many countries. Bio-optical models [7] [8] [9] [10] have been proposed for estimating these optical properties; these models are not always highly accurate, in coastal areas, since the optical properties of these water bodies do not depend exclusively on phytoplankton [11], except when there are high-intensity events such as phytoplankton blooms
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
