Data from: A path towards appropriate degradation experiments for assessing carbon sequestration potential of macroalgae

The biodiversity and climate crises have increased the urgency to
understand turnover rates and drivers of marine carbon sequestration.
Efforts have concentrated on measuring degradation of macroalgae, to
quantify how much of their carbon might be sequestered. We systematically
reviewed literature on macroalgal degradation, compiling 364 measurements
of exponential decay constant k. To date, most degradation
experiments (1) are carried out in aquaria or shallow environments, (2)
span short timescales, (3) use dried or frozen material, or (4) rarely
incorporate environmental gradients driving degradation. Decay constants
were higher in intertidal vs. subtidal habitats, for pre-treated algal
tissue compared to fresh, and when refractory material was present rather
than absent. These patterns have implications for estimates of export
efficiency of macroalgal carbon to the deep ocean. Synthesis: We
recommend that future studies of macroalgal degradation (1) adopt
standardized approaches, such as using fresh material and litter bag mesh
size of 10mm, to make studies more comparative, (2) measure degradation
with sufficient frequency to robustly estimate decay constants and/or
refractory material, and (3) incorporate environmental gradients,
including depth, light and oxygen availability, to improve estimates of
macroalgal carbon remineralisation rates during transport to deeper
water.