Kongsfjorden flagship program

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Kongsfjorden, an icy archipelago having a length of about 40 km and width ranging from 5 to 10 km, is a glacial fjord in the Arctic (Svalbard). It lies in the northwest coast of Spitsbergen, the main island of Svalbard, and is a site where warmer waters of the Atlantic meet the colder waters of the Arctic. Being an open fjord without sill it is largely influenced by the processes on the adjacent shelf. The Transformed Atlantic Water (TWA) from the west Spitsbergen current and the glacier-melt freshwater at the inner fjord creates strong temperature and salinity gradients along the length of the fjord. Southerly winds will produce down-welling at the coast and cause hindrance on exchange processes between the shelf and the fjord, while the northerly winds will move the TWA water below the upper layer towards the coast. The melt water during summer not only stratifies the upper water column but significantly alters the turbidity.

This would have profound influence on the seasonality in the phytoplankton biomass and primary production. Thus, an altered interaction between the Atlantic water with the (turbid) melt waters from tidal glaciers on a seasonal to inter-annual time-scale is likely to affect the pelagic ecosystem in the fjord. Alternately, the benthic ecosystem is more likely to be affected by long-term changes in the fjord hydrography and sedimentation.

 

Against the above backdrop of the climate sensitivity of the fjord system,  NCAOR has initiated an ambitious multi-institutional program of long-term monitoring of the Kongsfjorden by deploying an  Ocean-Atmosphere mooring system with regular repeat transects to measure physical and biogeochemical parameters on a seasonal scale.  The overall objective is to establish a long-term comprehensive physical, chemical, biological and atmospheric measurement programme to study:

 

  • The variability in the Arctic/Atlantic climate signal by understanding the interaction between the freshwater from the glacial run-off and Atlantic water from the west Spitsbergen current.
  • The effect of interaction between the warm Atlantic water and the cold glacial-melt fresh water on the biological productivity and phytoplankton species composition and diversity within the fjord.
  • The winter convection and its role in the biogeochemical cycling.
  • The trigger mechanism of spring bloom and its temporal variability and biomass production, and
  • The production and export of organic carbon in the fjord with a view to quantify the CO2 flux.

To achieve the above objectives a two-prong measurement strategy needs to be adopted.

 

  1. To collect long-term time-series data on oceanographic (currents, temperature, salinity, turbidity) and biological parameters (PAR, O2, fluorescence) through deploying an ocean mooring.
  2. Repeat transects to monitor the variability in the physical and biogeochemical parameters on an intra-seasonal to inter-annual time scale.

 

The in situ measurements during repeat transect monitoring are being carried out to cover 3 seasonal transitions.

 

As a prelude to the initiation of the above project, systematic CTD casts and surface sediment sampling were carried out during the summer months of May-July 2010 from different locations extending from the mouth to the head of the fjord.  Repeat measurements were continued at these pre-defined stations through the three seasons of 2011 and 2012.