How much carbon do marshes store?
Low marsh tower
High marsh tower
Radio
antenna
CO2 Analyzer
3D Anemometer
Air temperature
Relative humidity
Light Sensor
Soil temperature
Water level
Although uptake and release of CO2 in the winter are small,
winter measurements are important in order to get a true annual
budget, so one tower, sited on higher ground, stays up year round
(above). Its light sensors, normally on the marsh nearby, are
moved to a more protected and accessible location on the marsh
near the Rowley field house (below).
The tower sited in the low marsh, shown here during a flooding
tide, operates from early spring through late fall. It is taken down
for the winter, when ice movement over the marsh surface could
damage it.
CO2
Release
Carbon
loss
CO2
Uptake
Carbon
gain
Example of data output of CO2 exchange for one year.
CO2
Release
Carbon
loss
CO2
Uptake
Carbon
gain
• Negative values at the end of the year for NEE indicate
that some percentage of the carbon taken up by marsh
grasses is stored in the sediment.
• There are year-to-year differences in the amount stored,
driven largely by marsh productivity, which varies
depending on weather during each growing season.
• Long-term measurements of NEE are necessary to
determine if the amount of carbon being accumulated
and stored in the sediment is enough to help marshes
keep up with future sea-level rise.
Cumulative Net Ecosystem Exchange (NEE) of CO2,
Pictures of the marsh through spring, summer and fall seasons, and cartoons
illustrating the associated change in magnitude and direction of CO2 exchange.
showing net release of CO2 though winter, switching to
net uptake in spring and summer, and reversing
direction again in the fall. Note that the cumulative
values do not return to zero but end the year with net
uptake…or a net gain in the carbon “bank” of the
marsh.
Plum Island Ecosystems Long Term Ecological Research
High marsh tower
Low marsh tower