OpKROP field blog
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 15-29 September 2025
28-29 September: Goodbye and Thanks for all the zooplankton!
That’s it! We’re done with our OpKROP field campaigns!
The last weekend kept us busy. Estelle had to finish her experiments, Emily had to get Apherusa out of the water and ready for her return to the mainland, the data punching never ended, and we had to pack the lab and get everything ready for shipping.
By Sunday, all the snow had disappeared in a rainstorm on Saturday evening.
On Monday morning, however, the snow was back and with it very bad visibility. This delayed our departure from Ny-Ålesund by several hours; Emily and Estelle had to re-book their flights to the mainland and everyone was rather irritated and annoyed. Not the best way to end the campaign.
After we all get some rest we will proudly look back on what we archived over the last 9 month: 4 Ny-Ålesund based campaigns, one cruise; 127 water samples (for nutrients, chlorophyll, and optical properties); 201 zooplantkon samples; thousands of Calanus pictures, and hundreds of km of acoustic surveys with Apherusa. Lot’s of work awaits us now processing and analysing these data.
27 September: Wrapping up
Only Emily, Estelle and Malin are left in Ny-Ålesund, tying up the lose ends. Estelles experiments are still running, but we started packing up the lab. We also had spend considerable time this week putting all the data into the computer, and that work is still ongoing. And we had to weight our dry weight samples.
Meanwhile, Apherusa was brought back on land but not without causing Emily some headache. The remote control decided this morning to stop working, and one of the tires of Apherusas trailer is flat… there is always something with her…
Meanwhile, Malin finally had time to write the OpKROP progress report (definitely some progress to report!).
And it is melting in Ny-Ålesund. We went through 3 seasons this week – from warm sunny autumn colors to deep winter to melting season.
25 September: No more days at sea - Apherusas last mission and Teisten is broken
Today was supposed to be our last day out with Teisten. We had one item left on our agenda- an Apherusa survey of KB5. But yesterday Teisten lost its ruder and limped back into harbor. This morning she was lifted on land and she is out of operation for the foreseeable future.
That was of course an disappointment, but we can’t really complain since we otherwise had accomplished everything else this year.
KB5 is too far away from Ny-Ålesund to send Apherusa there on her own. Instead Emily and Tomasz piloted her from the Marine Lab and send her on a survey between KB3 and KB4. Apherusa was back in the harbour by dinner time and this was another last – her last mission for OpKROP.
We also had to say more Good Byes as Laura left in the morning, and Tomasz in the afternoon.
The weather was still nice, and Ny-Ålesund had turned into a winter wonderland.
24 September: Another day in the lab and an excursion
We’re still analysing the zooplankton samples in the lab, but after lunch we took the time for an excursion the geodetic centre of the Norwegian Mapping Authorities. The large antennas are essential to ensure maps and global positioning systems are correct and are impressive to see. We spend a very informative hour at the station before heading back to the lab.
At 20:00 in the evening we finished the sample analysis! Jipi!
23 September: Lab day, more snow and furry creatures
The days are starting to blur into each other and the lack of sleep is starting to show. This field campaign has been quite intense. We have been out with Teisten every day for 6 days in a row. Today we stayed in the lab, dealing with the pump and net samples, Lauras fecal pellet incubations and Estelles experiments.
Outside even more snow had fallen, and white furry creatures roam around town.
22 September: Night sampling
It’s the equinox and at this time of the year the vertical migration of zooplankton is most pronounced.
Laura had analysed the last 20 years of data from the acoustic sensors on the mooring (ADCP) and the data show that at this time of the year the strongest downward migration occurs between 1-4 o’clock in the morning. She was therefore very keen on repeating the sampling with the pump that we had tried out in March. The idea is to catch the migrators as they leave the surface (therefore we needed to sample at dawn instead of going out at dusk) and to use molecular tools to investigate what they have eaten and if that changes over time.
The Teisten captain was up for it, and at midnight Laura, Malin and Estelle headed out to the mooring site. Here we deployed the pump at 30 m depth and collected zooplankton in 20 min intervals. Meanwhile, we took zooplankton net samples every 30 min. This was done between 1-4am in the hope of capturing the peak in the migration. We will first know next autumn if we sampled at the right time, since we have to wait for the recovery of the mooring to check the data in the ADCP.
The night was cloudy but calm, and everything went smoothly. We returned pretty tired to the marine lab at 5 am. Here we had to process the samples right away since we needed to preserve the copepods with a full stomach. If we would leave the copepods standing for a few hours to sleep they would emptied their guts and there would be nothing left for us to analyse. We were done by breakfast and finally could get some sleep. Later in the afternoon we were back in the lab to start analysing the community composition in the pump and net samples. Overall, we had taken 21 samples in just 4 hours, so this will take some time…
Diel vertical migration (DVM):
Some zooplankton species conduct diel vertical migration: they migrate vertical through the water column over a daily cycle, going to deeper waters during daytime and migrating to upper water layers during night. This an adaptation to minimize predation: when the sun is illuminating the upper water layers, organisms can hide at depth in darkness. And when the sun has set it is save migrate up to the surface and utilize food sources in surface layers.
In OpKROP, we studied these vertical migration patterns and how they change with season and environmental conditions using acoustic data from the ADCP on the moorings. We still have open questions about who is migrating and what is controlling this behaviour. This is not as easy to study as one would think. It requires repeated sampling over the entire day, sampling over the short vertical intervals, and there is always the risk of disturbing the community when sampling at night with lights on.
21 September: And one more day at sea
For the last two days our main focus was on making sure that David could take the optics profiles at all stations. We had accomplished that yesterday, and David could pack his gear today. Meanwhile, Laura, Estelle and Ru went back to the mooring site to conduct the zooplankton sampling that we still had not done. They returned in the early afternoon and we spend a few hours in the lab to process the new samples.
Meanwhile, the Apherusa team went ahead with the calibration of the echosounder. A surprisingly low-tech but tricky procedure by which a metal sphere has to be place in a perfect position directly underneath the transducer using fishing lines and a lot of patience. Matters were not helped by a sudden computer crash… just a normal day in the Arctic…
Today is also the equinox and that brought the first snow to Ny-Ålesund!
And since Ru and David are leaving tomorrow, it was time for the first Good Byes.
20 September: Another sunny day at at sea
Another day out with Teisten. The sea had calmed down and the sun was still shining. Emily had send Apherusa out to the mooring site in the morning to check conditions and the sea had calmed sufficiently to enable us to take the optical profiles at the remaining stations. Ru joined David, Malin and Laura today. Meanwhile, Apherusa did survey the mooring site and KB4.
At the end of the day we had manage to take all Davids sampling in just 2 days, including two bonus stations! That also meant that this was Davids last trip out with Teisten…
And for the first time this week we managed to finish the lab work by dinner time and could relax a bit in the evening.
19 September: Another sunny day at the glacier front
Today we headed out again with Teisten. The focus was getting the optical profiles done. While David had finally made it to Ny-Ålesund, he was scheduled to leave again already on Monday, so the delay had reduced his time in Ny-Ålesund two 2 possible sampling days -today, Friday, and tomorrow, Saturday. He will need Sunday to pack up again. Malin, David and Laura headed out to the outer station of our transect, the Mooring site. But while the sun was still shining, the sea was not as calm anymore and we were met by a big swell as we headed towards the sampling site. Change of plans- we decide to try the inner stations and found ourselves back at the glacier front. While the sea was calmer here, a very cold wind was blowing down the glaciers. But we could deploy the gear and ended up sampling at KB5, KB8, Raudvika and close to KB4. A very successful day! Meanwhile in Ny-Ålesund, Tomasz and Ru went out to the light observatory to install a new sensor, and Estelle set up her experiments in the lab. We returned with lots of water samples to process and had another late evening in the Marine lab.
18 September: A sunny day at the glacier front
Ny-Ålesund is a radio silence zone, and we are only allowed to use the radio signal to pilot Apherusa on certain days. Today was one of these days and we had therefore scheduled a long day to take Teisten and Apherusa to the inner part of Kongsfjorden and survey the glacier front. While the rest of our team was finally on their way to Ny-Ålesund, we could not wait for their arrival and we headed out right after breakfast. It was another lovely day in Kongsfjorden. We headed to KB8, and Emily continued here marine biological training helping Malin with the net sampling on deck. Meanwhile Apherusa surveyed the glacier front. We also headed into Raudvika again for some additional zooplankton samples. As we returned to Ny-Ålesund in the evening we were finally reunited with the rest of the team! They were right away set to work in the lab, and it became another late evening processing samples.
17 September: First sampling
Today was our first sampling campaign with Teisten and Apherusa at KB3. Apherusa was piloted by Emily and Tomasz from the Marine Lab, but for the Teisten work we needed to find some helping hands. Fortunately two of our colleagues from the Alfred Wegener Institute, who are currently working in the Marine Lab, were happy to join Malin on Teisten to help out with the sampling!Sunshine and calm seas made work easy, and by mid-afternoon we had successfully surveyed the area with Apherusa and had taken 10 Zooplankton nets. Malin spend the rest of the afternoon and evening processing the samples, with some help from Emily (Physical Oceanographer by training) who demonstrated very promising marine biological skills in picking arrow worms!
16 September: Launching Apherusa
Today was all about getting ready for the first sampling campaign tomorrow. Even though we are understaffed with half of the team stuck in Tromsø, we need to get going. The weather forecast looks good, we can’t waste one day. Malin unpacked the lab boxes, while Emily woke up Apherusa, and Tomasz took at trip to the ArcLight Observatory to check that everything is running as it should there. In the afternoon we could launch Apherusa. We’re ready for action!
15 September: Our fourth and final Ny-Ålesund field campaign
We’re back in the high north for our fourth and final OpKROP campaign – this time coinciding with the autumn equinox. Unfortunately, not all members of our team made it here today. For the first time this year the weather interfered with our travel plans. While we would have expected problems reaching Ny-Ålesund in January or March, we did not expect to run into problems in September and that it would be the weather in Tromsø that would cause these problems… But fog over the airport in Tromsø prevented the plane from Oslo to land and thus our team members traveling from Scotland missed their flight to Longyearbyen and consequently to Ny-Ålesund and are now stuck in Tromsø. Hopefully, they will get here with the Thursday plane but we’re loosing valuable time for sampling and are working on Plan B. Meanwhile, Malin had the shortest and easiest trip from Longyearbyen to Ny-Ålesund in the morning, while Emily and Tomasz had a stressful morning in foggy Tromsø but managed a last-minute re-booking and got here in the afternoon.
Conditions in Ny-Ålesund are rather beautiful: the first snow has fallen on the mountain tops and the fjord is nice and calm.
OpKROP Field Campaign 16-26 June 2025
26 June: End of June Campaign
Today we all flew out of Ny-Ålesund. Now it’s time for some well deserved summer holidays. But we will be back in Ny-Ålesund in September for the last OpKROP campaign during the autumn equinox. Before that, we will be in Kongsfjorden for a few days at the end of August to service the moorings and conduct some additional sampling.
The OpKROP June team: Malin, Emily, Carina, David and Laura
25 June: More packing
Packing, cleaning, weighing of samples and general life administration continued on Wednesday. But we also found time for a quick trip out to the ArcLight Observatory to check out the facilities. In September we will install a new sensor to test out.
It’s been a busy week, and these last two days were no different.
24 June: Packing up
Time flies when you’re having fun, and this time we definitely had fun. And we were efficient!
By mid-day, we had managed to processes all of the samples we took yesterday and could packed up the lab. In between we got interviewed by Italian TV. And then we spend some time weighing the zooplankton dry weights. Meanwhile, Apherusa did one more trip out in the fjord and then came back on land. And then we spend quite a lot of time punching data, making sure we have documented everything we did the last week, caught up with the real world and all unanswered e-mails in our inbox.
In the evening we had time for a little walk and saw some polar fox cubs.
What a difference 3 month make: to the left the zooplankton samples from the Mooring site we took in March. Zooplankton abundance was very low back then. To the right the samples from June. Especially below 100 m we had very high densities of Calanus copepods. It's quite impressive how much biomass they manage to build up in just 3 month - from almost nothing to a thick soup!
23 June: Last day of sampling- already!
Today we took Teisten back to the inner part of Kongsfjorden to sample at the two remaining stations of our transect, KB5 and KB4. KB5 is close to where the glacier front used to be 15 years ago. Today the glacier front is a few Kilometers away and we were once again surrounded by icebergs. The sun was hiding behind the clouds and it got a bit cold out on deck, but the wind had calmed down so sampling was easy and we could enjoy the view. Emily and Carina were driving Apherusa back and forth while David, Laura and Malin sampled. Once we finished at KB5 we decided to explore Raudvika, a bay in front of the southern front of Kongsvegen where the glacier has retreated so far that it is now land terminated. David was interested to measure the optical properties here to compare with the measurements we did last week in front of the marine terminated glacier. After that little excursion we caught up with Apherusa on the way to KB4, halfway towards Ny-Ålesund. We conducted our last sampling here and were back in town in time for some shopping in Kongsfjordenbutikken.
This was our last day out sampling. We have now visited all our standard stations plus some additional locations at the glacier front, and we have conducted all the Apherusa surveys we planned to do. Overall sampling in June has been very efficient and so much more pleasant when nothing is freezing!
22 June: Sunday in Ny-Ålesund
Fieldwork is always great fun, and one of the main reasons most of us chose this career path. But it is also exhausting. Our days are long, and while it is a privilege to cruise around glacier ice and bask in the sun watching seals, the work we do on board is actually quite demanding and takes a lot of energy. And once we are back on land, we can’t just drop everything and go to bed. Samples need to be processed, some of them right away (even after 12 hours on board); gear needs to be cleaned and dried; and there is a lot of heavy lifting. So today, we took things easy to recover from the last days. That does not mean we did not work. We still had samples from yesterday to process, and Laura and David also have proposal deadlines upcoming. But we all slept in and enjoyed a Ny-Ålesund brunch before getting back to the lab and/or the PC. And we managed to go for a little walk before dinner to explore the surroundings.
Tomorrow we have another long day on Teisten.
21 June: Midsummer sampling
We went out with Teisten in the morning to sample at the mooring site, and conditions were not quite as pleasant as during our previous outings. Just in time for the big midsummer party, the clouds had come in and some wind came up. It wasn’t nearly as bad as in March but sampling takes more time when you have to balance yourself and move the boat constantly back into position because it’s been drifting too far from the sample site. But we manage our sampling program by midday and the kitchen had saved us brunch to keep us going in the lab until evening. Then we made time to join the Ny-Ålesund pirate-themed midsummer party down by the beach in front of the Marine Lab. Even though the midnight sun was covered by clouds everyone had a great evening!
20 June: a day in the lab
The weather was still gorgeous, but after a full day of sampling yesterday, we needed a day in the lab to process everything. Water needed to be filtered, CDOM needed to be measured and we had 9 net samples to sort through. At the end of the day we can conclude that the community now in June is very different from January and March. First of all, there is much higher copepod abundance than in spring, which is not unexpected. They have been reproducing during the spring bloom and are very good in building up high biomass in a short amount of time. We also saw very high abundance of brittle star larvae. They are in the water column for only a short period of time before settling on the sea.
When it comes to macrozooplankton, pelagic amphipods are dominating. This is in sharp contrast to what we observed in January and March. Back then we mainly found krill and arrow worms, which are sparse now.
19 June: A magical day at the glacier front
Fieldwork in the Arctic on a small vessel can often be hard and unpleasant. But sometimes it’s just fabulous! Today we had a one of these magical days you sometimes get in the Arctic. We were sampling in the inner part of Kongsfjorden close to the glacier front under a blue sky and sunshine, no wind and surrounded by glacier ice and the most magnificent scenery! It cannot get better. The entire team headed out today: Emily and Carina were joining us, piloting Apherusa from Teisten; David, Laura and Malin were out on deck and took care of the sampling. We sampled at one of the permanent stations (KB8) and then made our way closer to the glacier to take optical profiles in the glacial outflow. We also kept an eye on the echosounder and tried to target sounds scattering layers with our nets. And in between we enjoyed the scenery, watched out for seals and admired the icebergs drifting by. We stayed out all day, collecting lots of zooplankton and data while Emily and Carina skillfully piloted Apherusa through the ice. What a day!
Timelapse of our full sampling procedures at KB8
What are we actually sampling while we're out there?
- Optical properties
First, we take a vertical profile with a number of optical sensors mounted on a rig. These sensors measure wavelength absorption, attenuation and backscattering as well as chlorophyll and coloured dissolved organic materials (CDOM) fluorescence. In addition, it includes at CTD measuring temperature and salinity in the water column. These sensors will tell us more about the optical properties of Kongsfjorden, that are affected by changes in algal concentrations and inputs of glacial sediment from nearby glaciers, as well as CDOM that may either be introduced from adjacent offshore waters or delivered by freshwater inputs. Since the extremely seasonal light climate strongly influences timing of algal growth and glacial melt, optical properties of the fjord will vary across seasons and across the fjord. The aim of these measurements is to establish a set of representative optical profiles from the mooring site up to the head of the fjord that will allow us to better exploit the long time series of observations that have been primarily collected at the mooring site over the last twenty years.
2. Water samples
The next gear that goes into the water is the Niskin bottle that allows us to sample water from specific depth. We take water samples from 4 depth and collect them in carboys that we bring back to the Marine Lab. Here we filter the water to determine the Chlorophyll a concentration, the concentration of total suspended matter and to measure CDOM.
3. Mesozooplankton sampling
Now is it time for the net sampling. We use a WP2 net with a mesh size of 180 µm to collect mesozooplankton from different depth layers. These samples are used to study which species and life stages are in the water column and how many, and to determine the biomass. The taxonomic analysis will be done back in our home Universities. In the Marine Lab we sort through some of the samples, pick out the larger species (krill, jellies, amphipods), measure their length and dry them to measure their biomass. We also take pictures of Calanus copepods to study how much lipids they have and how that changes over the seasons and across the fjord.
4. Macrozooplankton sampling
The last sample is taken with the larger plankton net, the WP3. It has a larger mesh size and opening than the WP2 and is designed to catch larger zooplankton such as krill and amphipods. Back in the Marine Lab we sort the catch by taxonomic groups and measure the length of krill, amphipods and arrow worms.
The reason we do that is to get a better idea of what we see with the echosounders. While we are sampling, Apherusa is taking acoustic surveys, which show us where we can find high densities of organism in the water column. But the acoustic data does not tell us what these organisms are. With the net sampling we get a better idea what could cause the backscatter that the echosounder is recording. Ideally, we would of course like to trawl for larger zooplankton and fish species to get a even better understanding of what is in the water column, but unfortunately little Teisten is not equipped for that type of sampling. Today we saw larger patches of organisms on the echosounder and we stopped to take several WP3 nets. In one of them we got a large shrimp! They are able to escape a net such as the WP3, so catching one of them indicates that there is a high density of them close to the glacier front.
18 June: Sampling in the sun!
In January and March we had our fair share of horrible weather and overall difficult conditions when going out sampling with Teisten. Today we got rewarded with the best sampling conditions one can hope for. Completely calm sea, nice temperatures and the sun even showed up! How easy our sampling program is when nothing freezes, the boat is not moving and you have to hold on for dear life while deploying gear at the same time. Today the toes did not get numb and we could take off our gloves without loosing fingers. Arctic fieldwork can be fun this way!
Laura, David and Malin went out to KB3 with Teisten after breakfast. This station is the one that is closest to Ny-Ålesund, so the trip out there does not take much time. But it is also the deepest station, so the sampling takes more time and therefore we like to start here. We deployed Davids optical sensors, took a CTD profile and water samples from 4 depth, and altogether 9 zooplankton samples. Meanwhile, Emily and Carina piloted Apherusa from land and send her to survey around KB3. Everything worked out perfectly, we even saw a minke whale surfacing close to Teisten. We were back in Ny-Ålesund just after lunch. But since we were so efficient in sampling we had to spend the entire afternoon and evening processing the samples in the lab… There is so much more zooplankton in the water now compared to the winter, and therefore so much more to sort…
17 June: Apherusa launching
Today we unpacked our gear and set up the lab. Meanwhile, Emily woke up Apherusa and had a few stressful hours troubleshooting. But all was working in the end and we could launch Apherusa after dinner. At the end of the day we we’re all set-up for the first round of sampling the next day.
16 June 2025 Back in town
It’s June, the midnight sun is shining, most of the snow is gone and we are back in Ny-Ålesund for our 3rd field campaign this year! This one is timed to coincide with the summer solstice. The team this time consists of Malin, Laura and David for the sampling from Teisten, and Emily and Carina to pilot Apherusa. We’ll have a day to unpacked and prepare before we start sampling. Hopefully the weather stays calm and the Belugas keep keeping us company!
What a difference 3 month made: Ny-Ålesund in March and June
OpKROP Field Campaign 17-31 March 2025
Copepod hotels
One of the main focus of the OpKROP project is using active acoustics to track seasonal and long-term changes in the vertical migration patterns of the pelagic community. Active acoustics allows us to observe changes in the vertical distribution of species with high time resolution, something we can’t achieve by taking net samples. We’ve been collecting active acoustic data in Kongsfjorden for 20 years. This year, we’re expanding this dataset by collecting additional data in different locations within Kongsfjorden using an echosounder on Apherusa, our unmanned vehicle, during our field campaigns.
While active acoustics helps us describe the vertical migration patterns of the community, it doesn’t allow us to distinguish between species because we observe multiple behaviors at once. As a result, we still don’t fully understand which species or groups of species are responsible for each type of behavior.
During the OpKROP campaign, Estelle Coguiec, our OpKROP post-doc, carried out several lab experiments to study the behavior of some key species detected by active acoustics, specifically macrozooplankton. The goal was to link their behavior in the lab with the migration patterns we observe in the field.
To study their behavior, Estelle used an instrument called the LAM, which stands for “Locomotor Activity Monitor.” We also refer to it as the “copepod hotel” because it consists of 32 chambers, each holding a transparent tube filled with seawater. In each tube, we place one organism for 48 hours. The LAM records when the organism crosses the middle of the tube, providing data on how active the organism is and how this activity changes over time.
We exposed the organisms to a light/dark cycle to mimic natural light patterns and observe their responses. We expect that their reactions in the lab will be similar to their behavior in the wild, despite the different conditions. Our goal is to link this behavior to vertical migration patterns, especially considering that part of the migration response may be driven by the organism’s internal clock. To account for this, we also exposed the organisms to complete darkness.
During the campaign in March, Estelle had ca. 400 individual organisms in her hotel. The data will now be analysed and we will repeat the experiments in June to see how the behaviour changes between March (when we still have a day-night light cycle) and June, when the midnight sun will be at its highest.
28-31 March: packing up
Friday morning, Laura, Jon and Kunuk left Ny-Ålesund. Only Emily and Estelle were left with the tasks processing yesterdays samples, finishing the lab experiments, packing, getting Apherusa back on land and preparing her for the next campaign. Needless to say, the final days were very busy.
But in between all of these tasks, they were rewarded by a partial sun eclipse on Saturday!
On Monday, Emily and Estelle left Ny-Ålesund and that marked the end of our March field campaign. We have now surveyed the Polar Night and the spring equinox and are looking forward to experience Kongsfjorden in summer. We will be back for the next campaign in June!
27 March: Sampling in inner Kongsfjorden
Today we went out with Teisten for the last time for this campaign. This time we worked in the inner part of the fjord. Due to the distance to Ny-Ålesund, we can not run Apherusa here remotely on 5g but have to use the radio connection. Today was one of the few days when we were allowed to do that (otherwise Ny-Ålesund is a radio silence area), and thus the Apherusa pilots Emily and Kunuk joined Jon and Estelle to pilot Apherusa from Teisten At KB4, Apherusa conducted an acoustic survey and at the same time took vertical light profiles with the light sensor mounted on the CTD on Apherusa. Meanwhile, Teisten continued to KB5 (or as close to KB5 as we could get since KB5 itself was ice covered (ca. 5cm thick ice)). Here we took water and zooplankton samples while we were observed by couple of Walrus that were very curious and were wondering what we were doing. It feel like being at the aquarium but we were the fish!
Photos: E. Coguiec
26 March: Still processing samples
It’s been another busy day in the lab for Laura and Estelle as the processing of the zooplankton from the pump experiment continued. After two days in the lab we now have taken over 600 pictures of copepods. The pictures will be used to determine the size, lipid content and coloration of each copepod. We will then analyse if any of these parameters can be linked to the timing of the vertical migration.
Meanwhile, the rest of the team prepared Apherusa for the tomorrows campaign. Emily and Kunuk managed to fix the winch on Apherusa during the stormy days last week. Now we could try out if everything was working as it should. Apherusa was launched again and the winch was now equipped with a light sensor that was mounted on a frame together with a CTD. Cruising around the harbour, Apherusa took several light profiles of the water column.
In between all the zooplankton, we also had the chance to observed four Orcas in the fjord just outside the lab. It is quite uncommon to see Orcas in Ny-Ålesund, so it was very exciting to spot them as we returned to the lab after lunch.
Photos: E. Coguiec
We have some data!
Last week, our colleagues from UNIS on board Helmer Hanssen were kind enough to take a a number of CTDs (i.e. vertical profiles of temperature and salinity) along a transect from the inner part of Kongsfjorden to the outer part. Here is the transect, showing that the water masses in the fjord now in March are very homogeneous. Water temperatures are below 1 degree Celsius throughout the fjord, and slightly colder in the inner part. We still don’t measure any fluorescence in the water column, indicating low algae biomass in the water.
When compared with similar data from last September, we see how much the water has cooled down now in March (from +8 degrees in upper 50 m in September 2024 to 0-1 degrees in March), while the surface layer of freshwater that is prominent in September (due to glacier and river-run off) has disappeared in winter.
Temperature, salinity and fluorescence along a transect from KB1 to KB5 (inner Kongsfjorden) 20 March 2025
Temperature, salinity and fluorescence along a transect from KB0 to KB5 (inner Kongsfjorden) in September 2024.
25 March: Sample processing
A busy day sampling is always followed by a busy day processing samples. The zooplankton team spent the day processing all the samples collected yesterday: 10 pump samples and 12 wp3 net! Abundance is low in the pump sample (common for this time of the year), but preliminary observations indicate a nice peak in abundance e of small copepods just after light starts decreasing (i.e. we caught the upward migrating populations). With a little luck we’ll be able to get more of a scatterer story once all net sample and the acoustics and light data are analysed together. Oveeall, it ws a busy day in the lab, and the work it is not yet finished.
Meanwhile, the Apherusa team got Apherusa back on land to continue fixing the winch. And in the afternoon, Jon conducted some light measurement just under the surface water in the harbor.
The weather was very nice and we enjoyed a nicely colored sky in the evening.
Photos: E. Coguiec
24 March: Evening migration
One aspect we are studying in OpKROP using the time series data from the mooring is vertical migration behavior of zooplankton. Some zooplankton species conduct diel vertical migration: they migrate vertical through the water column over a daily cycle, going to deeper waters during daytime and migrating to upper water layers during night. This an adaptation to minimize predation: when the sun is illuminating the upper water layers, organisms can hide at depth in darkness. And when the sun has set it is save migrate up to the surface and utilize food sources in surface layers. Using the acoustic sensors on the mooring (ADCP), we have studied these vertical migration patterns and how they change with season and environmental conditions. However, we still have open questions about who is migrating and what is controlling this behaviour. This is not as easy to study as one would think. It requires repeated sampling over the entire day, sampling over the short vertical intervals, and there is always the risk of disturbing the community when sampling at night with lights on.
Therefore, Laura and her colleagues at SAMS have come up with a new approach to try to catch the migrators at the time of top migration (at dusk or dawn, and during the equinox). A pump is deployed at 30 m depth just before dusk, with a hose pumping the water and the zooplankton community up on deck of Teisten where the sample is caught in the zooplankton net. This is done over several hours until the sun has set, resulting in a number of samples of the zooplankton community from 30 m taken in 20 min intervals. Differences in community composition and abundance over time will then provide insight who is coming to the surface during dusk. This set-up was tried out in Loch Etive (Scotland) a few weeks ago.
On Monday we tried this approach for the first time in Kongsfjorden. The team went out with Teisten to the mooring site at 5 pm and arrived early enough to set up everything to sample during the dusk-migration. Everything was ready to go by 6 pm and while the pump was pumping, the team could take a CTD profile and stratified net samples with the WP3 net (a net designed to catch larger zooplankton species). Nets were taken every hour, while pump samples were taken in 20 min intervals until 9 pm. Apherusa joined Teisten at the sampling site and remained stationary next to Teisten and recorded acoustics. Sampling went smoothly and the team returned to the harbor at 10:30 pm, where they first had to remove an iceberg before anchoring the boat.
(Photos: E. Coguiec)
22 March: Apherusa is launched
Today the zooplankton team processed the samples collected the evening before, while the Apherusa team couldfinally launch Apherusa. After some piloting testing in the harbor, Apherusa head out for its first survey around KB3, piloted by Emily and Kunuk from the marine lab. She returned back to the harbor just in time before the wind picked up again.
By evening, the wind had turned into a blizzard and we needed to protect our self as much as possible when going outside. That’s the Arctic in March!
maximal protection against the wind (Photo: E. Coguiec)
21 March: More ice and some sampling
The night was stormy, but the weather calmed down in the morning. The team was reshuffled today: Malin left in the morning and was replaced by Jon Cohen, our colleague from the University in Delaware who currently spends his Fullbright fellowship with us at UiT.
The plan was to go out with Teisten in the late morning to sample further in the fjord, but the storm in the night had consolidated the ice in the harbour and the team was first able to leave in the later afternoon to enjoy a cold but successful sampling trip to KB4.
We ain’t going no-where… time to switch to sea ice sampling? (Photo: Laura Hobbs)
20 March: Sample processing
The wind had picked up again, but after yesterdays sampling-marathon we had more than enough to do in the lab. David spend the day downloading data and calibrating his instruments; Emily and Kunuk continued fixing the winch on Apherusa; and Laura, Estelle and Malin sorted through 13 zooplankton samples, measuring a few hundred krill and arrow worms, photographing 100 Calanus, and setting up experiments.
It's a mens world (at least in March)
The Calanus population in Kongsfjorden in March was dominated by male C. finmarchicus. Male Calanus are short-lived, they reproduce and die, and are usually not observed for most parts of the year.
A grey and cold day in Kongsfjorden. Our colleagues from UNIS were in the fjord with on board of Helmer Hanssen and took the samples at KB3 that we did not manage to take yesterday.
19 March: Sampling and sea sick
Despite the ice in the harbour, we managed to get out with Teisten on Wednesday, 19 March. The aim was to sample at the mooring site and at KB3, one of our standard station in the deepest basin of the fjord. Our sampling included a CTD profile to measure temperature and salinity in the water column, water sampling from distinct depth to estimate the concentration of Chlorophyll a and suspended matter, optical profiling to measure absorption and scattering in the water column, as well as a number of zooplankton nets to determine species composition, abundance and biomass.
The wind had calmed and the sun was shining as we headed out. But once we approach our first sampling site we realised that the swell had build up substantially, which made Teisten a rather unstable platform. That made sampling (i.e. trying to stand upright on Teisten while deploying heavy gear and fiddling with small screws and bottles) rather challenging. In addition, half of the team had to deal with sea sickness (not a pleasant experience) and at -20 degrees we lost the feeling in our toes pretty soon (steel-capped rubber boots may be save but not warm). Despite all that, we actually got almost everything done! Between stations we dropped one team member off in the Ny-Ålesund, and were supplied with freshly backed cinnamon buns by another team member, which restored our energy level enough to enable us to sample most parameters at the second station. After 6.5 h at sea we could finally defrost in the marine lab in the later afternoon, and after a well deserved dinner we spend the evening processing the water samples.
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 (if not credited otherwise)