Reviews and syntheses: Spatial and temporal patterns in seagrass metabolic fluxes

[摘要] Seagrass meadow metabolism has been measured for decades to gain insight into ecosystem energy, biomass production, food web dynamics, and, more recently, to inform its potential in ameliorating ocean acidification (OA). This extensive body of literature can be used to infertrends and drivers of seagrass meadow metabolism. Here, we synthesize theresults from 56 studies reporting in situ rates of seagrass gross primaryproductivity, respiration, and/or net community productivity to highlightspatial and temporal variability in oxygen ( O 2 ) fluxes. We illustratethat daytime net community production (NCP) is positive overall and similaracross seasons and geographies. Full-day NCP rates, which illustrate thepotential cumulative effect of seagrass beds on seawater biogeochemistryintegrated over day and night, were also positive overall but were higherin summer months in both tropical and temperate ecosystems. Although ouranalyses suggest seagrass meadows are generally autotrophic, the effects onseawater oxygen are relatively small in magnitude. We also find positivecorrelations between gross primary production and temperature, although thiseffect may vary between temperate and tropical geographies and may changeunder future climate scenarios if seagrasses approach thermal tolerancethresholds. In addition, we illustrate that periods when full-day NCP ishighest could be associated with lower nighttime O 2 and increaseddiurnal variability in seawater O 2 . These results can serve as first-order estimates of when and where OA amelioration by seagrasses may belikely. However, improved understanding of variations in NCP DIC : NCP O 2 ratios and increased work directly measuringmetabolically driven alterations in seawater pH will further inform thepotential for seagrass meadows to serve in this context.

[学科分类] 大气科学