A 6-year study of pelagic primary production in a
freshwater influenced sub-Arctic fjord system
– with a view to the past
Thomas Juul-Pedersen
Kristine E. Arendt
John Mortensen
Martin Blicher
Diana Krawczyk
Søren Rysgaard
and many more…
The climate is changing...(temperature anomalies: average of 2008-12 versus 1880-2012 average)
NASA/Goddard Space Flight Center Scientific Visualization Studio
Rysgaard & Glud (2007) Bioscience vol 58
Changing sea ice and primary production
Observed melting of the Greenland Ice Sheet(changes in elevation from 2003 to 2006)
NASA/Goddard Space Flight Center Scientific Visualization Studio
Marine monitoring and
research since 2005
“MarinBasis aim to establish long-
term data series of key parameters
in order to understand how the
distribution and composition of
marine plants and animals and the
marine carbon cycle is affected by
climatic changes in Arctic regions”
Historical data from 1955-67
The Godthåbsfjord system (64˚N)
- Area ca. 2013 km2
- Average depth 250 m (>600m)
- Limited sea ice cover
- Water temp. above 0°C
- Seasonal freshwater input
The Godthåbsfjord system (64˚N)
Nuuk
Phytoplankton are the key primary producers
MacroalgaeBenthicalgae
A deep fjord (avg. 250 m)Limited sea ice
Sea ice algae
Freshwater is a key driver in the fjord ecosystem
J. Mortensen et al. (2011)
Freshwater induced circulation modes
Estuarine circulation Sub-glacial circulation
Entrainment of
ambient water
(ratio of 1:30)
FjordOffshoreFjordOffshore
Phytoplankton biomass and freshwater
T. Juul-Pedersen et al. (in prep.)
Phytoplankton production (0-45m)
T. Juul-Pedersen et al. (in prep.)
14C in situ incubation method at 5 depths
(light corrected)
Phytoplankton production and nutrients (0-45m)
T. Juul-Pedersen et al. (in prep.)
Phytoplankton production and nutrients (0-45m)
T. Juul-Pedersen et al. (in prep.)
Ongoing seasonal study on
nutrient limitation
Nutrient addition experiments(fjord-coast transects in May, August, October 2013)
Phytoplankton production (0-45m)
T. Juul-Pedersen et al. (in prep.)
Phytoplankton production (0-45m)
T. Juul-Pedersen et al. (in prep.)
Phytoplankton production (0-45m)
Spring Summer/Autumn
T. Juul-Pedersen et al. (in prep.)
Seasonal freshwater input
Snow melt Glacial melt
T. Juul-Pedersen et al. (in prep.)
Phytoplankton species composition(seasonal grouping based on cluster analysis of species composition)
D. Krawczyk et al. (submitted)
Seasonal groups Months Species/groups
Winter November-
March
Diatoms: Chaetoceros spp.
Thalassionema nitzschioides
Nitzschia spp.
Silicoflagellates: Dictyocha speculum
Dinoflagellates & Ciliates
Spring April-
May
Haptophytes: Phaeocystis sp.
Diatoms: Thalassiosira spp.
Fragilariopsis spp.
Summer/Autumn June-
October
Diatoms: Chaetoceros spp.
Thalassionema nitzschioides
Dinoflagellates
Winter Spring Summer/Autumn
Phytoplankton species composition
D. Krawczyk et al. (submitted)
System resilience and capacity?(a shift in species composition in spring 2009)
D. Krawczyk et al. (submitted)
2006-08 & 2010-12 2009
T. Juul-Pedersen et al. (in prep.)
System resilience and capacity?(a shift in species composition in spring 2009)
3500 parameter monitored at
Zackenberg (74˚N) and Godthåbsfjord (64˚N)
ClimateBasic
ClimateSnowHydrology
UV radiation
ClimateSnowHydrology
UV radiation
Soil
Gas flux
UV radiation
Soil
Vegetation
Gas fluxLakes
Arthropods
Mammals/
birds
Oceanography
Zooplankton
Mammals/birds
Sea iceSea waterSea bottom
GeoBasic BioBasic MarineBasic
Irradiance
GlacioBasic
ClimateSnow
Glacier ice
Snow (sea ice)
Algae
Greenland Ecosystem Monitoring (GEM)
’The mother of the Sea’Aka Høegh
Merci pour votre de attention
Thank you for your attention
For more information
www.g-e-m.dk & www.natur.gl
