Predicting Carbon Isotope Discrimination in Eelgrass (Zostera marina L.) From the Environmental Parameters- Light, Flow, and [DIC]

Authors

Meredith L. McPherson
Richard C. Zimmerman, Old Dominion UniversityFollow
Victoria J. Hill, Old Dominion University

Document Type

Article

Publication Date

2015

DOI

10.1002/lno.10142

Publication Title

Limnology and Oceanography

Volume

60

Issue

6

Pages

1875-1889

Abstract

Isotopic discrimination against ¹³C during photosynthesis is determined by a combination of environmental conditions and physiological mechanisms that control delivery of CO₂ to RUBISCO. This study investigated the effects of light, flow, dissolved inorganic carbon (DIC) concentration, and its speciation, on photosynthetic carbon assimilation of Zostera marinaL. (eelgrass) using a combination of laboratory experiments and theoretical calculations leading to a mechanistic understanding of environmental conditions that influence leaf carbon uptake and determine leaf stable carbon isotope signatures δ¹³C. Photosynthesis was saturated with respect to flow at low velocity ~ 3 cm s^-1, but was strongly influenced by [DIC], and particularly aqueous CO₂ (CO_2(aq)) under all flow conditions. The non-linear responses of light- and flow-saturated photosynthesis to [DIC] were used to quantify the maximum physiological capacity for photosynthesis, and to determine the degree of photosynthetic carbon limitation for light-saturated photosynthesis, which provided a mechanistic pathway for modeling regulation of carbon uptake and ¹³C discrimination. Model predictions of δ¹³C spanned the typical range of values reported for a variety of seagrass taxa, and were most sensitive to [DIC] (predominantly [CO_2(aq) ]) and flow, but less sensitive to DIC source [CO2_(aq)vs. HCO¯3]. These results provide a predictive understanding of the role of key environmental parameters (light, flow, and DIC availability) can have in driving δ¹³C of seagrasses, which will become increasingly important for predicting the response of these ecosystem engineers to local processes that affect light availability and flow, as well as global impacts of climate warming and ocean acidification in the Anthropocene.

Original Publication Citation

McPherson, M.L., Zimmerman, R.C., & Hill, V.J. (2015). Predicting carbon isotope discrimination in eelgrass (Zostera marina l.) from the environmental parameters light, flow, and dic. Limnology and Oceanography, 60(6), 1875-1889. doi: 10.1002/lno.10142

Repository Citation

McPherson, Meredith L.; Zimmerman, Richard C.; and Hill, Victoria J., "Predicting Carbon Isotope Discrimination in Eelgrass (Zostera marina L.) From the Environmental Parameters- Light, Flow, and [DIC]" (2015). OES Faculty Publications. 110.
https://digitalcommons.odu.edu/oeas_fac_pubs/110