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Article
Decoupling of Net Community Production and Export Production at Submesoscale Fronts in the Sargasso Sea
Geosciences Faculty Scholarship
  • Meg Estapa, Skidmore College
  • D. A. Siegel
  • K O. Buesseler
  • R. H. R. Stanley
  • M. W. Lomas
  • N. B. Nelson
Document Type
Article
Publication Date
1-1-2015
Keywords
  • NCP and export decouple on scales below 5km yet balance on mesoscales Biogeochemical fluxes vary more strongly than coincident physical parameters Higher trophic level biogeochemical parameters were more spatially variable,
  • Biogeochemical fluxes vary more strongly than coincident physical parameters,
  • Higher trophic level biogeochemical parameters were more spatially variable
Abstract
Determinations of the net community production (NCP) in the upper ocean and the particle export production (EP) should balance over long time and large spatial scales. However, recent modeling studies suggest that a horizontal decoupling of flux-regulating processes on submesoscales (≤10 km) could lead to imbalances between individual determinations of NCP and EP. Here we sampled mixed-layer biogeochemical parameters and proxies for NCP and EP during 10, high-spatial resolution (~2 km) surface transects across strong physical gradients in the Sargasso Sea. We observed strong biogeochemical and carbon flux variability in nearly all transects. Spatial coherence among measured biogeochemical parameters within transects was common but rarely did the same parameters covary consistently across transects. Spatial variability was greater in parameters associated with higher trophic levels, such as chlorophyll in >5.0 µm particles, and variability in EP exceeded that of NCP in nearly all cases. Within sampling transects, coincident EP and NCP determinations were uncorrelated. However, when averaged over each transect (30 to 40 km in length), we found NCP and EP to be significantly and positively correlated (R = 0.72, p = 0.04). Transect-averaged EP determinations were slightly smaller than similar NCP values (Type-II regression slope of 0.93, standard deviation = 0.32) but not significantly different from a 1:1 relationship. The results show the importance of appropriate sampling scales when deriving carbon flux budgets from upper ocean observations.
Published In
Global Biogeochemical Cycles
Pages
1266-1282
DOI
10.1002/2014GB004913
Citation Information
Estapa, M. L., D. A. Siegel, K. O. Buesseler,R. H. R. Stanley, M. W. Lomas, andN. B. Nelson (2015), Decoupling of netcommunity and export production onsubmesoscales in the Sargasso Sea,Global Biogeochem. Cycles, 29 ,1266–1282, doi:10.1002/2014GB004913.