Skip to main content

ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Coastal Ocean Processes
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1486261
This article is part of the Research Topic Advanced Monitoring, Modelling, and Analysis of Coastal Environments and Ecosystems View all 10 articles

Light Attenuation Parameterization in a Highly Turbid Mega Estuary and its Impact on the Coastal Planktonic Ecosystem

Provisionally accepted
Qiyinan Lin Qiyinan Lin 1Zhixuan Feng Zhixuan Feng 1*Yihe Wang Yihe Wang 1Xue Wang Xue Wang 1Zhaoxuan Bian Zhaoxuan Bian 1Fan Zhang Fan Zhang 1Fang Cao Fang Cao 1Hui Wu Hui Wu 1,2Ya Ping Wang Ya Ping Wang 1,3
  • 1 State Key Laboratory of Estuarine and Coastal Research, Faculty of Earth Sciences, East China Normal University, Shanghai, Shanghai Municipality, China
  • 2 School of Mathematical Sciences, East China Normal University, Shanghai, China
  • 3 School of Geography and Ocean Sciences, Nanjing University, Nanjing, Jiangsu Province, China

The final, formatted version of the article will be published soon.

    Light is essential for phytoplankton photosynthesis and many other biogeochemical processes in the aquatic system. However, light regimes vary greatly in the estuaries and coasts due to the optical complexity of the Case-2 waters. In this study, observed vertical profiles of photosynthetically active radiation (PAR; 400-700 nm) in a highly turbid mega estuary, the Changjiang (Yangtze River) Estuary, are used to quantify the effects of sedimentary and biogeochemical components on PAR attenuation in the water column and associated ecological impacts. The in-situ data suggest suspended sediment plays the most crucial role in light diffuse attenuation coefficient (Kd) distribution, followed by salinity (i.e., an index for colored dissolved organic matter) and phytoplankton chlorophyll-a. A new parameterization of Kd, based on suspended sediment, chlorophyll-a concentration, and salinity, is fitted using multiple linear regression. The previous and new Kd parameterizations are further applied to a coupled hydrodynamics-sediment-ecosystem model to simulate spring phytoplankton blooms. Comparative model runs reveal that the new Kd parameterization resulted in a better representation of the spring bloom patterns in magnitude, horizontal distribution, and vertical thickness of the high chlorophyll-a band offshore the turbidity maximum zone during the spring bloom. In summary, accurate representations of underwater light fields in the optically complex Case-2 water are critical in understanding biophysical processes that control planktonic ecosystem dynamics in the estuaries and coastal seas.

    Keywords: Light Attenuation, photosynthetically active radiation, river plume, Suspended sediment concentration, spring phytoplankton bloom, Changjiang Estuary Spatiotemporal Variability, environmental factors

    Received: 25 Aug 2024; Accepted: 08 Oct 2024.

    Copyright: © 2024 Lin, Feng, Wang, Wang, Bian, Zhang, Cao, Wu and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Zhixuan Feng, State Key Laboratory of Estuarine and Coastal Research, Faculty of Earth Sciences, East China Normal University, Shanghai, 200062, Shanghai Municipality, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.