Net ecosystem production and carbon greenhouse gas fluxes in three prairie wetlands / Lauren E. Bortolotti, Vincent L. St. Louis, Rolf D. Vinebrooke, and Alexander P. Wolfe.

Includes bibliographical references (pages 423-425).

In central North America, prairie wetlands provide
many important ecosystem services including
attenuating floods, improving water quality, and
supporting biodiversity. However, over half of
these wetlands have been drained for agriculture.
Relatively little is known about the functioning of
these ecosystems either in their natural state or
restored after drainage. We characterized net
ecosystem production and carbon greenhouse gas
(GHG) fluxes (carbon dioxide [CO2] and methane)
in the open-water zones of three prairie wetlands
over two ice-free seasons. These wetlands included
a natural site and sites restored 3 and
14 years prior to study (hereafter ‘‘recently restored’’
and ‘‘older restored’’). We also assessed
how two techniques for estimating metabolic status,
the diel oxygen method (used to measure
NEP) and net CO2 fluxes, compared. The diel
oxygen method suggested that the restored wetlands
were net heterotrophic across years,
whereas the natural wetland was net heterotrophic
in 1 year and net autotrophic in the other.
Similar conclusions arose from quantifying net
CO2 fluxes, although this technique proved to be
relatively insensitive for understanding metabolic
status at a daily temporal scale owing to the
influence of geochemical processes on CO2 concentrations.
GHG efflux was greatest from the
recently restored wetland, followed by the older
restored and natural wetlands. Overall, GHG flux
rates were high and variable compared with other
inland aquatic ecosystems. Although restoration
may progressively return wetland functioning to
near-natural states, our results highlight the
necessity of preventing wetland drainage in the
first place to preserve ecosystem functions and
services.