Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations Stony Brook University, School of Marine and Atmospheric Sciences, 239 Montauk Hwy, Southampton, NY 11968, USA
05 Apr 2013
Received: 05 Nov 2012 – Published in Biogeosciences Discuss.: 14 Nov 2012Abstract. While larval bivalves are highly sensitive to ocean
acidification, the basis for this sensitivity and the longer-term
implications of this sensitivity are unclear. Experiments were performed to
assess the short-term (days) and long-term (months) consequences of larval
stage exposure to varying CO2 concentrations for calcifying bivalves.
Higher CO2 concentrations depressed both calcification rates assessed
using 45Ca uptake and RNA : DNA ratios in Mercenaria mercenaria and
Argopecten irradians larvae with RNA : DNA ratios
being highly correlated with larval growth rates (r2>0.9).
These findings suggested that high CO2 has a cascading negative
physiological impact on bivalve larvae stemming in part from lower
calcification rates. Exposure to elevated CO2 during the first four
days of larval development significantly depressed A. irradians larval survival rates,
while a 10-day exposure later in larval development did not, demonstrating
the extreme CO2 sensitivity of bivalve larvae during first days of
development. Short- (weeks) and long-term (10 month) experiments revealed
that individuals surviving exposure to high CO2 during larval
development grew faster when exposed to normal CO2 as juveniles
compared to individuals reared under ambient CO2 as larvae. These
increased growth rates could not, however, overcome size differences
established during larval development, as size deficits of individuals
exposed to even moderate levels of CO2 as larvae were evident even
after 10 months of growth under normal CO2 concentrations. This "legacy
effect" emphasizes the central role larval stage CO2 exposure can play
in shaping the success of modern-day bivalve populations.
Revised: 11 Feb 2013 – Accepted: 18 Feb 2013 – Published: 05 Apr 2013
Citation: Gobler, C. J. and Talmage, S. C.: Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations, Biogeosciences, 10, 2241-2253, doi:10.5194/bg-10-2241-2013, 2013.