Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Discussion papers
https://doi.org/10.5194/bg-2019-203
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2019-203
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 03 Jun 2019

Submitted as: research article | 03 Jun 2019

Review status
This discussion paper is a preprint. A revision of this manuscript was accepted for the journal Biogeosciences (BG) and is expected to appear here in due course.

Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off

Johnna M. Holding1, Stiig Markager2, Thomas Juul-Pedersen3, Maria L. Paulsen1, Eva F. Møller3, Lorenz Meire3,4, and Mikael K. Sejr1 Johnna M. Holding et al.
  • 1Arctic Research Centre, Bioscience, Aarhus University, Ny Munkegade 114, bldg. 1540, DK-8000 Aarhus C, Denmark
  • 2Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
  • 3Greenland Climate Research Centre, Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
  • 4Department of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute of Sea Research and Utrecht University, Yerseke, the Netherlands

Abstract. Primary production on the coast and in Greenland fjords sustains important local and sustenance fisheries. However, unprecedented melting of the Greenland Ice Sheet (GrIS) is impacting the coastal ocean, and its effects on fjord ecology remain understudied. It has been suggested that as glaciers retreat, primary production regimes may be altered rendering fjords less productive. Here we investigate patterns of primary productivity in a Northeast Greenland fjord (Young Sound, 74 N), which receives run-off from the GrIS via land-terminating glaciers. We measured size fractioned primary production during the ice- free season along a spatial gradient of meltwater influence. We found that, apart from a brief under-ice bloom during summer, primary production remains low (between 50–200 mg C m−2 day−1) however steady throughout the ice-free season, even into the fall. Low productivity is due to freshwater run-off from land-terminating glaciers causing low light availability and strong vertical stratification limiting nutrient availability. The former is caused by turbid river inputs in the summer restricting phytoplankton biomass to the surface and away from the nitracline. In the outer fjord where turbidity plays less of a role in light limitation, phytoplankton biomass moves higher in the water column in the fall due to the short day- length as the sun angle decreases. Despite this, plankton communities in this study were shown to be well adapted to low light conditions, as evidenced by the low values of saturating irradiance for primary production (5.8–67 µmol photons m−2 s−1). With its low but consistent production across the growing season, Young Sound offers an alternative picture to other more productive fjords which have highly productive spring and late summer blooms and limited fall production. However, patterns of primary productivity observed in Young Sound are not only due to the influence from land-terminating glaciers but are also consequences of the nutrient deplete coastal boundary currents and the shallow entrance sill, features which should also be considered when generalizing about how primary production will be affected by glacier retreat in the future.

Johnna M. Holding et al.
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Johnna M. Holding et al.
Johnna M. Holding et al.
Viewed  
Total article views: 279 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
220 57 2 279 15 0 3
  • HTML: 220
  • PDF: 57
  • XML: 2
  • Total: 279
  • Supplement: 15
  • BibTeX: 0
  • EndNote: 3
Views and downloads (calculated since 03 Jun 2019)
Cumulative views and downloads (calculated since 03 Jun 2019)
Viewed (geographical distribution)  
Total article views: 229 (including HTML, PDF, and XML) Thereof 227 with geography defined and 2 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 16 Sep 2019
Publications Copernicus
Download
Short summary
Phytoplankton sustain important fisheries along the coast of Greenland. However climate change is causing severe melting of the Greenland Ice Sheet, and continued melting has the potential to alter fjord ecosystems. We investigate how freshwater from the Ice Sheet is impacting the environment of one fjord in Northeast Greenland causing a low production of phytoplankton. This fjord may be a model for how some fjord ecosystems will be altered following increased melting and glacial retreat.
Phytoplankton sustain important fisheries along the coast of Greenland. However climate change...
Citation