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Net heterotrophy and carbonate dissolution in two subtropical seagrass meadows


Title (Dublin Core)

Net heterotrophy and carbonate dissolution in two subtropical seagrass meadows

Description (Dublin Core)

<p>The net ecosystem productivity (NEP) of two seagrass
meadows within one of the largest seagrass ecosystems in the world, Florida
Bay, was assessed using direct measurements over consecutive diel cycles
during a short study in the fall of 2018. We report significant differences
between NEP determined by dissolved inorganic carbon (NEP<span class="inline-formula"><sub>DIC</sub></span>) and by
dissolved oxygen (NEP<span class="inline-formula"><sub>DO</sub></span>), likely driven by differences in air–water gas
exchange and contrasting responses to variations in light intensity. We also
acknowledge the impact of advective exchange on metabolic calculations of
NEP and net ecosystem calcification (NEC) using the “open-water” approach
and attempt to quantify this effect. In this first direct determination of
NEP<span class="inline-formula"><sub>DIC</sub></span> in seagrass, we found that both seagrass ecosystems were net
heterotrophic, on average, despite large differences in seagrass net
above-ground primary productivity. NEC was also negative, indicating that
both sites were net dissolving carbonate minerals. We suggest that a
combination of carbonate dissolution and respiration in sediments exceeded
seagrass primary production and calcification, supporting our negative NEP
and NEC measurements. However, given the limited spatial (two sites) and
temporal (8&thinsp;<span class="inline-formula">d</span>) extent of this study, our results may not be
representative of Florida Bay as a whole and may be season-specific. The
results of this study highlight the need for better temporal resolution,
accurate carbonate chemistry accounting, and an improved understanding of
physical mixing processes in future seagrass metabolism studies.</p>

Creator (Dublin Core)

B. R. Van Dam
C. Lopes
C. L. Osburn
J. W. Fourqurean

Subject (Dublin Core)


Publisher (Dublin Core)

Copernicus Publications

Date (Dublin Core)


Type (Dublin Core)


Identifier (Dublin Core)


Source (Dublin Core)

Biogeosciences, Vol 16, Pp 4411-4428 (2019)

Language (Dublin Core)


Relation (Dublin Core)

Provenance (Dublin Core)

Journal Licence: CC BY