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  • Seasonal metabolism and carbon export potential of a key coastal habitat: The perennial canopy‐forming macroalga Fucus vesiculosus
Title: Seasonal metabolism and carbon export potential of a key coastal habitat: The perennial canopy‐forming macroalga Fucus vesiculosus
Abstract The important role of macroalgal canopies in the oceanic carbon (C) cycle is increasingly being recognized, but direct assessments of community productivity remain scarce. We conducted a seasonal study on a sublittoral Baltic Sea canopy of the brown algaFucus vesiculosus, a prominent species in temperate and Arctic waters. We investigated community production on hourly, daily, and seasonal timescales. Aquatic eddy covariance (AEC) oxygen flux measurements integrated ~ 40 m2of the seabed surface area and documented considerable oxygen production by the canopy year‐round. High net oxygen production rates of up to 35 ± 9 mmol m−2h−1were measured under peak irradiance of ~ 1200 μmol photosynthetically active radiation (PAR) m−2s−1in summer. However, high rates > 15 mmol m−2h−1were also measured in late winter (March) under low light intensities < 250 μmol PAR m−2s−1and water temperatures of ~ 1°C. In some cases, hourly AEC fluxes documented an apparent release of oxygen by the canopy under dark conditions, which may be due to gas storage dynamics within internal air spaces ofF. vesiculosus.Daily net ecosystem metabolism (NEM) was positive (net autotrophic) in all but one of the five measurement campaigns (December). A simple regression model predicted a net autotrophic canopy for two‐thirds of the year, and annual canopyNEMamounted to 25 mol O2m−2yr−1, approximately six‐fold higher than net phytoplankton production. Canopy C export was ~ 0.3 kg C m−2yr−1, comparable to canopy standing biomass in summer. Macroalgal canopies thus represent regions of intensified C assimilation and export in coastal waters.  more » « less
Award ID(s):
1851424 1824144
PAR ID:
10078290
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Limnology and Oceanography
Volume:
64
Issue:
1
ISSN:
0024-3590
Page Range / eLocation ID:
p. 149-164
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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