Abstract
Abstract. Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analyzed using a seaFAST-pico™ coupled to an Element XR sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interesting insights into the Fe sources in this area. Overall, DFe concentrations ranged from 0.09±0.01 to 7.8±0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland, and Newfoundland margins likely due to riverine inputs from the Tagus River, meteoric water inputs, and sedimentary inputs. Deep winter convection occurring the previous winter provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth and lead to relatively elevated DFe concentrations within subsurface waters of the Irminger Sea. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles in the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers located in the different basins and at the Iberian Margin were found to act as either a source or a sink of DFe depending on the nature of particles, with organic particles likely releasing DFe and Mn particle scavenging DFe.
Highlights
The North Atlantic Ocean is known for its pronounced spring phytoplankton blooms (Henson et al, 2009; Longhurst, 2007)
We considered the different contributions of sea ice melt (SIM), meteoric water (MW), and saline seawater, at Stations 53, 61, and 78 using the procedure and mass balance calculations that are fully described in Benetti et al (2016)
From stations 68 to 78 surface waters were characterized by a minimum of salinity and a maximum of oxygen (S = 34.91, O2 = 285 μmol kg−1, θ ≈ 3 ◦C) and corresponded to the newly formed Labrador Sea Water (LSW)
Summary
The North Atlantic Ocean is known for its pronounced spring phytoplankton blooms (Henson et al, 2009; Longhurst, 2007). Phytoplankton blooms induce the capture of aqueous carbon dioxide through photosynthesis, and conversion into particulate organic carbon (POC). This POC is exported into deeper waters through sinking and ocean currents. Phytoplankton must obtain, besides light and inorganic carbon, chemical forms of essential elements termed nutrients to be able to photosynthesize. The availability of these nutrients in the upper ocean frequently limits the activity and abundance of these organisms together with light conditions (Moore et al, 2013). Nutrient depletion due to biological consumption is considered a major factor in the decline of blooms (Harrison et al, 2013)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
