OpKROP field blog
Next campaign coming up in March 2025. Follow our field blog here.
In OpKROP, we synthesize 20 year of data from Kongsfjorden that are based on measurements taken with moored instruments. While moored instruments provide high temporal resolution data, they are limited to a single spatial point. This raises a central question:
How representative are point measurements from the mooring for the wider fjord system?
To address this question, we will conduct four dedicated seasonal surveys of Kongsfjorden in 2025 to capture the biological system’s seasonality and monitor spatial heterogeneity across the fjord. We will use UiT’s unmanned surface vehicle (USV), Apherusa for continuous sampling with multifrequency hydroacoustic echosounders (EK80, WBAT, Kongsberg) to resolve the vertical distribution of fish and zooplankton (38 and 200 kHz) in the water column. The survey area will extend from Kronebreen in the inner Kongsfjorden to the mooring site further out in the fjord, thus expanding the geographical coverage of biological and biogeochemical observations. The USV surveys are complemented by additional measurements from KingsBay’s small vessel, MS Teisten, including CTD profiles, in situ optical measurements, water sampling, and zooplankton sampling.
OpKROP Field Campaign 17-31 March 2025
18 March: Northerly winds and too much ice
We spend the day unpacking, setting up the lab and getting our USV “Apherusa” ready for action. The lab set-up was largely stress free, but the computer to pilot Apherusa caused quite some stress. But things worked out in the end, and we’re ready to head out for sampling tomorrow… if weather allows… It is still quite cold in Ny-Ålesund and in addition the wind started blowing strongly from the north, pressing a field of drift ice into the harbor. Teisten (the research vessel from Kings Bay) tried to head out today but could not get through the ice. The forecast says more northerly winds tomorrow, so we’ll have to wait and see if we start sampling tomorrow or not.
17 March: Arrival Ny-Ålesund
Our March campaign in Ny-Ålesund has started! It’s our spring campaign, or rather “spring-equinox” campaign because with temperatures around -20 degrees spring is definitely not in the air. But the light is back and we finally can enjoy the amazing landscape in all its Arctic glory. The March-Team consists of Malin, Estelle, Emily, Kunuk (all UiT), Laura (SAMS) and David (U Stratheclyde). The flight from Longyearbyen to Ny-Ålesund Monday afternoon provided a stunning views of snow-covered glaciers and mountains. Tomorrow we’ll unpack and hopefully head out to sample soon.
OpKROP Field Campaign January 2025
The January 2025 campaign marked the first of the seasonal campaigns. Having conducted polar night campaigns almost annually each January since 2012 we were well aware of the challenges of conducting marine surveys in darkness and in a season prone for low temperatures, strong winds, and poor visibility due to snowfall. With this in mind, we approached the campaign pragmatically and with tempered expectations. However, the weather and technology worked largely in our favor, making the campaign an overall success.
A team of six OpKROP researcher went to Ny-Ålesund from 3-20 January 2025. This included Malin Daase (project leader), Emily Venables (USV pilot), Tomasz Kopec (USV co-pilot), David McKee (marine optics), Maxime Geoffroy (hydroacoustics) and master student Carina Krämer.
The sampling plan (using state of the art mapping technology…)
Field diary
Clear skies and northern lights greeted us in when we arrived in Ny-Ålesund 6 January.
Apherusa was launched the next day, and on Wednesday, 9 January, we could conduct the first Apherusa survey around the monitoring site KB3, while Malin went out with Teisten to take water and zooplankton samples at KB3. The weather was on our side, cold but clear skies and relatively calm seas.
On Thursday, 10 January, we conducted a USV survey around the mooring site. Apherusa was piloted from shore, and David and Malin took Teisten to the site. Strong winds and high waves made sampling on board Teisten challenging and there was strong interference in the acoustic data from Apherusa, so sampling was cut short. The weather turned into a blizzard by later afternoon.
On Friday, we had full blizzard, but by Saturday, 11 January, we could go out again, survey KB4 with Apherusa and Teisten.
On Sunday we had another blizzard, but were busy in the lab processing samples.
On Monday, 13 January, the weather had calmed down and the polar night was at its best: full moon and clear sky.
We went with Teisten all the way to the inner part of Kongsfjorden, close to the glacierfront of Kronebreen. Emily and Tomasz piloted Apherusa from Teisten, Malin and David did the sampling. It was cold, but the scenery was beautiful. The WBAT showed high backscattering in the water column, suggesting a higher abundance of organisms here compared to the mooring site.
Tuesday and Wednesday, the weather had turned unpleaseant again. We made some attempts at sampling but had to return early. Thursday, 16 January, was our last sampling day and survey KB5 and went back to the mooring site for some zooplankton nets.
We also spend some time calibrating the EK80 on Apherusa.
On Friday, it was time to pack the lab and equipment. In the morning, a few test runs were conducted around the harbour with Apherusa and the 70 khz transducer. It was a cold and rather windy day, but we could get Apherusa out of the water before Dinner.
The weekend was spend punching data, Apherusa maintenance, packing and report writing. Maxime gave a talk in the Zeppelin lounge after dinner about his kayak expedition through the north-west passage last summer.
Aperhusa is back inside, safe and sound. Happy scientists!
Monday, 20 January, was departure day and Ny-Ålesund said Good Bye with purple skies! The light is coming back, and we will be back in March.
OpKROP Field Campaign June 2024
In June 2024, we had the opportunity to conduct a first field campaign in Kongsfjorden to try out Apherusa and conduct sampling using UiT’s reserach vessel Helmer Hanssen.
The main objectives of the cruise were:
- Hydroacoustic surveys in Kongsfjorden using the EK60 on Helmer Hanssen and “Apherusa”
- Recovery and re-deployment of two moorings in Kongsfjorden: currently, there are 3 moorings deployed in Kongsfjorden. The standard KROP mooring will be serviced in September, but the two additional moorings (ExFOOB) that have been deployed last year in collaboration with AWI and NPI were recovered and redeployed during this cruise.
- Pelagic sampling at standard stations in Isfjorden and Konsgfjorden
- Pelagic trawling to ground truth acoustic observations: to assess the species composition and biomass in the sound scattering layers detected by the EK60 and/or Apherusa trawls were deployed at selected sites.
We were lucky with the weather and had a very successful campaign and are ready for the next campaign in the polar night.
Successful recovery of ExFOBB1 in brilliant summer weather
Acoustic survey of the glacier front with Apherusa
Photos: Malin Daase