Chesapeake Bay Acidification
.......................................................................................................................................
11
associated carbonate system measures. Underway pCO
2
/TA measurements are also occasionally
performed using the same instrument mounted on a boat. The University of Delaware (Cai et al.) is
conducting oceanographic cruises in both the Delaware and Chesapeake estuaries to make carbonate
chemistry measurements. Miller and Cai are two investigators known to be monitoring carbonate
chemistry dynamics in nearshore and mainstem of Chesapeake Bay, but there are no doubt other
investigators, laboratories, and programs that focus on carbon chemistry or biogeochemistry that can
participate in CBAN.
From the non-profit sector, the Sustainable Fisheries Partnership has been collaborating with investigators
at Virginia Tech University (Kuhn et al.) and the University of New Hampshire (Salisbury et al.) to track
water quality and carbonate chemistry in oyster hatcheries in Chesapeake Bay. These efforts are aimed at
understanding baseline water conditions under which they are operating, and to enable these hatcheries to
detect changes that may affect the health and yield of their oyster spat production.
The above are some examples of current activities aimed at understanding carbonate chemistry and
acidification in Chesapeake Bay. There are many additional research projects directed at understanding
the impacts of elevated CO
2
on species that live in Chesapeake Bay (e.g. Breitburg of SERC, combined
effects of diurnal DO and pH cycling on oysters and fish; Lane/Miller of CBL, effects of elevated CO
2
on
juvenile blue crab growth, calcification, physiology; and Megonigal/Neale/Miller of SERC, tidal
outwelling of DIC and TA). A concerted effort should be made to identify the regional base of expertise
in carbonate chemistry, biogeochemistry, acidification research, and environmental monitoring in and
around Chesapeake Bay in order to assess that community’s capacity to measure and understand short
term and long terms changes in the Bay’s carbonate chemistry system. Additionally, a list of experts,
potential collaborators and partners, and monitoring programs that are already focused on coastal
acidification questions, but in other regions, should be compiled.
Charge Question E – What information gaps and data requirements must be considered in the design
of a Chesapeake Bay Acidification Network?
1.
How important is elevated atmospheric CO
2
to pCO2/pH of the water?
Because many coastal
ecosystems experience frequent shifts in pCO
2
/pH that are not the direct effect of a physical
exchange of CO
2
across the air:sea interface (e.g., biological activity such as photosynthesis and
benthic respiration, export of TCO
2
from land to water via riverine input and tidal exchange), a
fuller characterization of carbon flux among environmental compartments is required. Thus,
understanding how a changing atmosphere will affect water chemistry requires a better
understanding of the processes and mechanisms at work in Chesapeake Bay, many of which are
local in nature. Furthermore, it is important to understand the influence of the open ocean
acidification signal that is accumulated in offshore ocean water, and then mixed into the Bay.
2.
How important are the fluxes that cross ecological subsystem boundaries (e.g., land:estuary,
sediment:water, ocean:estuary) to carbonate chemistry cycling and fluctuations?
Compared to
the open ocean, the carbonate chemistry of Chesapeake Bay is far more influenced by chemical
constituents that originate on land, bay sediments, intertidal wetlands, and other boundaries of the
Bay water column (Fig 1). The global trend of increasing atmospheric CO
2
that drives open ocean
acidification will interact with long-term trends in riverine alkalinity export, pCO
2
export from
tidal wetlands, and the effects of eutrophication in estuarine sediments, and many other
interactions. Management decisions that consider estuarine acidification will need to consider the
relative importance of the different drivers of carbonate system change.
