title: Net ecosystem production and carbon dioxide fluxes in the Scheldt estuarine plume.
abstract: BACKGROUND
  A time series of 4 consecutive years of measurements of the partial pressure of CO2 (pCO2) in the Scheldt estuarine plume is used here to estimate net ecosystem production (NEP).
  
  
  RESULTS
  NEP in the Scheldt estuarine plume is estimated from the temporal changes of dissolved inorganic carbon (DIC). The strong seasonal variations of NEP are consistent with previous reports on organic carbon dynamics in the area. These variations are related to successive phytoplankton blooms that partly feed seasonally variable heterotrophy the rest of the year. On an annual time scale the Scheldt estuarine plume behaves as a net heterotrophic system sustained with organic carbon input from the Scheldt inner estuary and the Belgian coast. During one of the years of the time-series the estuarine plume behaved annually as a net autotrophic system. This anomalous ecosystem metabolic behaviour seemed to result from a combination of bottom-up factors affecting the spring phytoplankton bloom (increased nutrient delivery and more favourable incoming light conditions). This net autotrophy seemed to lead to a transient aa accumulation of organic carbon, most probably in the sediments, that fed a stronger heterotrophy the following year.
  
  
  CONCLUSIONS
  The present work highlights the potential of using pCO2 data to derive detailed seasonal estimates of NEP in highly dynamic coastal environments. These can be used to determine potential inter-annual variability of NEP due to natural climatic oscillations or due to changes in anthropogenic impacts.
authors.affiliation: University of Liège, Chemical Oceanography Unit, Institut de Physique (B5), B-4000, Liège, Belgium. alberto.borges@ulg.ac.be
authors.forename: Alberto V
authors.initials: AV
authors.lastname: Borges
authors.forename: Kevin
authors.initials: K
authors.lastname: Ruddick
authors.forename: Laure-Sophie
authors.initials: LS
authors.lastname: Schiettecatte
authors.forename: Bruno
authors.initials: B
authors.lastname: Delille
mesh_terms: D052818:Autotrophic Processes; D001530:Belgium; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D017753:Ecosystem; D004784:Environmental Monitoring; D052836:Heterotrophic Processes; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D010839:Phytoplankton / Q000378:metabolism; D012621:Seasons; D012623:Seawater / Q000737:chemistry*; D014872:Water Movements
chemical_list: D002245:Carbon Dioxide; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
references.citation: Water Res. 2001 Apr;35(5):1344-7
references.pmid: 11268856
references.citation: Nature. 2003 Nov 6;426(6962):32
references.pmid: 14603308
references.citation: Appl Opt. 2000 Feb 20;39(6):897-912
references.pmid: 18337965
references.citation: Science. 1998 Jul 10;281(5374):234-6
references.pmid: 9657712