Data from: Coral hypoxia response curve analysis

Oxygen (O2) availability is essential for healthy coral reef functioning,
yet how continued loss of dissolved O2 via ocean deoxygenation impacts
performance of reef building corals remains unclear. Here we examine how
intra-colony spatial geometry of important Great Barrier Reef (GBR) coral
species Acropora may influence variation in hypoxic thresholds for
upregulation, to better understand capacity to tolerate future reductions
in O2 availability. We first evaluate application of more streamlined
models used to parameterise Hypoxia Response Curve data, models that have
been used historically to identify variable oxyregulatory capacity. Using
closed-system respirometry to analyse O2 drawdown rate, we show that a
2-parameter model returns similar outputs as previous 12th order models
for descriptive statistics such as the average oxyregulation capacity
(Tpos) and the ambient O2 level at which the coral exerts maximum
regulation effort (Pcmax), for diverse Acropora species. Following an
experiment to evaluate whether stress induced by coral fragmentation for
respirometry affected O2 drawdown rate, we subsequently identify
differences in hypoxic response for the interior and exterior colony
locations for the species Acropora abrotanoides, Acropora cf.
microphthalma, and Acropora elseyi. Average regulation capacity across
species was greater (0.78 to 1.03 ± SE 0.08) at the colony interior
compared to exterior (0.60 to 0.85 ± SE 0.08). Moreover, Pcmax occurred at
relatively low pO2 of <30% (± 1.24; SE) air saturation for all
species, across the colony. When compared against ambient O2 availability,
these factors corresponded to differences in mean intra-colony
oxyregulation, suggesting that lower variation in dissolved O2 corresponds
with higher capacity for oxyregulation. Collectively our data shows that
intra-colony spatial variation affects coral oxyregulation hypoxic
thresholds, potentially driving differences in Acropora oxyregulatory
capacity.