hide
Free keywords:
-
Abstract:
Reef-building corals form their calciumcarbonate skeletonswithin an
extracellular calcifying medium(ECM). Despite the critical role of the
ECM in coral calcification, ECM carbonate chemistry is poorly
constrained in vivo, and full ECM carbonate chemistry has never been
characterized based solely on direct in vivo measurements. Here, we
measure pH(ECM) in the growing edge of Stylophora pistillata by
simultaneously using microsensors and the fluorescent dye SNARF-1,
showing that, when measured at the same time and place, the results
agree. We then conduct microscopeguided microsensor measurements of pH,
[Ca2+], and [CO32-] in the ECM and, from this, determine [DIC](ECM) and
aragonite saturation state (Omega(arag)), showing that all parameters
are elevatedwith respect to the surrounding seawater. Our study provides
the most complete in vivo characterization of ECM carbonate chemistry
parameters in a coral species to date, pointing to the key role of
calcium-and carbon-concentrating mechanisms in coral calcification.
