Data from: Metabolic traits and thresholds to inform marine ecological conservation and restoration

The combined effects of anthropogenic pressures and climate change pose
significant threats to key habitat-forming species, such as seagrasses.
Understanding species' responses to environmental stressors and
identifying their tolerance thresholds are essential for effective
conservation and restoration efforts in coastal environments. Through a
mesocosm experiment, we assessed Posidonia oceanica's metabolic
responses under ecologically realistic conditions across three seasonal
periods (February-March, June-July, and October-November) when plants were
naturally acclimated to different temperature regimes. Within each period,
we tested plant responses to small temperature variations (ambient and two
increasing steps of 2°C) crossed with four turbidity levels (0-34 mg/L),
enabling construction of ecologically realistic thermal performance
curves. Our findings reveal that turbidity may impair P. oceanica
functioning, including decreased thermal performance and narrowed thermal
tolerance window, impairing photosynthesis and potentially limiting
growth. Metabolism increased with temperature up to a thermal optimum
(Topt) identified at 23 °C for all turbidity and exposure time treatment
levels. We demonstrate the relevance of stressor properties on P. oceanica
responses, with individuals exposed to the more extreme treatment (high
turbidity (34 mg/L) and increased exposure time (7 days)) presenting a
reduced optimal thermal tolerance with respect to control. We advocate
integrating metabolic traits into monitoring protocols as early warning
indicators of ecosystem stress. This approach can strengthen both
conservation and restoration initiatives by informing policy decisions,
particularly in the context of increasing coastal development and climate
change.