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Title: High‐Frequency CO 2 System Variability Over the Winter‐to‐Spring Transition in a Coastal Plain Estuary

Understanding the vulnerability of estuarine ecosystems to anthropogenic impacts requires a quantitative assessment of the dynamic drivers of change to the carbonate (CO2) system. Here we present new high‐frequency pH data from a moored sensor. These data are combined with discrete observations to create continuous time series of total dissolved inorganic carbon (TCO2), CO2partial pressure (pCO2), and carbonate saturation state. We present two deployments over the winter‐to‐spring transition in the lower York River (where it meets the Chesapeake Bay mainstem) in 2016/2017 and 2017/2018. TCO2budgets with daily resolution are constructed, and contributions from circulation, air‐sea CO2exchange, and biology are quantified. We find that TCO2is most strongly influenced by circulation and biological processes; pCO2and pH also respond strongly to changes in temperature. The system transitions from autotrophic to heterotrophic conditions multiple times during both deployments; the conventional view of a spring bloom and subsequent summer production followed by autumn and winter respiration may not apply to this region. Despite the dominance of respiration in winter and early spring, surface waters were undersaturated with respect to atmospheric CO2for the majority of both deployments with mean fluxes ranging from −9 to −5 mmol C·m−2·day−1. Deployments a year apart indicate that the seasonal transition in the CO2system differs significantly from one year to the next and highlights the necessity of sustained monitoring in dynamic nearshore environments.

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Author(s) / Creator(s):
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Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Journal of Geophysical Research: Oceans
Page Range / eLocation ID:
p. 7626-7642
Medium: X
Sponsoring Org:
National Science Foundation
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