Hopendjupet Seepage Area

Cruise preparations

Text and picture: Mariana Esteves

The weeks leading up to the cruise were hectic for all of the cruise participants, as it was essential that they made sure that they had prepared and packed everything that would be needed for the cruise and their specific sampling.

On Tuesday 30th November, many of the UiT based scientists got together to pack everything at the UiT cruise warehouse and prepare the zarges boxes filled with the essential equipment that will be transportated onto the R/V G.O.Sars in just a few days time.

Photo: Scientists preparing the crates with the worksuits and boots/gloves, and the pallets with the zarges boxes. Left to right: Mauro Pau, Karina Weiler, Marie Stetzler, Henry Patton.

Boarding the G.O.Sars

Text and picture: Mariana Esteves

Sunday 5th December

Today, 18 scientists and technicians from CAGE/UiT, NGU, NPD, and UNIS, boarded the G.O.Sars ready for the 11-day research cruise to the Hopendjupet Seepage Area.

The mood is high and there is a lot of excitement in the air. Will we see whales during the transit, will we find oil slicks on the sea surface, what will we see during the ROV dives? These are all questions ready to be answered over the coming days.

Starting with a 40 hour transit.

At present we will arrive to our study area on Tuesday evening, but until then we will be working hard to prepare the labs and ships facilities so that we are ready to start sampling when we arrive to the first site.

The weather forecast for the coming days seems relatively calm at present, so fingers crossed for a smooth transit and little-to-no sea sickness...

40-hour transit

Text and picture: Mariana Esteves

Monday 6th December

Late in the evening of the 5th, the G.O.Sars set off from Tromsø and embarked on the 40-hour transit to the first superstation.

During the night and early into Monday 6th, the G.O.Sars sailed into the Barents Sea, leaving behind the calm seas and protection inside the fjords. With the increase in wave size (video) and rocking of the ship, many onboard began to feel sea-sick. This is relativly common for sailors, particularly during the first couple of days out at sea.

Thankfully by the early afternoon on the 6th, the waves had calmed and the scientists onboard began to feel better, and were able to start preparing their labs and equipment ready for deployment when we reach superstation 1.

The final details before reaching the first superstation

Text and picture: Mariana Esteves

Once we arrive at the first superstation, scientists will work together with the ROV technicians to collect numerous different samples and image the seafloor.

The samples will be used for many different studies, including macro-faunal investigations, geochemical analyses, microbial analyses, and water column and air analyses.

This 40-hour transit time is therefore important for discussing and preparing the final sampling strategy.

In the picture above, PhD student Marie Stetzler is discussing with cruise leaders Monica Winsborrow and Jochen Knies the water column sampling stratergy.

Only 3 hours to go until we reach superstation 1

Text and picture: Mariana Esteves

Tuesday 7th December

The air is filled with excitement as we near the end of the transit. With only 3 more hours until we arrive to the first superstation, the scientists onboard are finalising their sampling strategies and completing any last-minute laboratory preparations.

Picture: This morning we had the pleasure of hearing Dr Vincent Carrier's microbial sampling strategy that he plans to implement once the push cores filled with sediments are on board and also the plans following the cruise.

CAGE21-6 is very much a multidisciplinary cruise, where we have a team of scientists with an array of backgrounds and expertise, from marine geologists, microbiologists, geophysicists, 'bubbleologists' (oceanographers studying the bubbles rising from the seep sites), geochemists, and biologists.

Together we are all working towards a common goal, to investigate the Hopendjupet Seepage Area.

Weather delays play

Text and picture:   Dr Henry Patton  

Wednesday 8th December

Data collection in the Barents Sea in December would always be to some extent dictated by the whim of the winter weather systems. As well as affecting being able to deploy equipment from the ship, choppy seas also introduce a lot of 'noise' into acoustic data when we try to scan the seabed. Not to mention too the state of scientist's stomachs and ability to focus on swaying computer screens.

Perhaps more than usual then, plans have to remain flexible, and always with multiple backup options to be considered. These first few days on site have proven challenging, and last night was no exception. With wind speeds reaching 20 m per second, for safety reasons those of us on the night shift had to postpone plans to collect water profile data via a 'CTD' - a large machine that must be winched over the side of the ship and then lowered down to the seafloor and back.  

But by around 2am the winds subsided and we took our chance to collect a CTD transect over our first superstation, successfully collecting dozens of water samples from various depths beneath the ship in order to quantify methane concentrations within the water column. 

At 8am the 'ROV crew' came on shift, and with the relatively calm conditions still holding we were able to deploy the ROV to the seafloor and collect the very first images of the Hopendjupet Seep Area. After months of planning and speculation we can finally see how this area looks and start to collect some precisely targeted data from these hydrocarbon seeps, much to everyone's relief and satisfaction.

Meet Ægir6000

Text and picture: Mariana Esteves

Thursday 9th December

For the first time, the Hopendjupet Seepage Area will be investigated using a remotely operated vehicle (ROV) -   the Ægir6000  . This was specifically designed to be a research ROV, the first of its kind in Norway.

With the ability to dive up to 6000m and carry a variety of scientific equipment and cameras, it is the ideal tool for observing what is happening at the seafloor in high resolution. The ability to clearly see the seafloor and surroundings enables scientists to precisely collect their samples (sediment, gas, water).

To carry the majority of the scientific equipment down to the seafloor, the ROV has a specialized 'basket', where the equipment can be attached and organised ahead of the ROV dive.

We are now on our second dive of the cruise, and already we have collected a lot of fantastic data thanks to the Ægir6000 and the very skilled engineers that are responsible for the ROV: Hibert Grovg, Eyvind Ernstsen, and Jörn Patrick.

Imaging the seafloor

Text and picture:   Associate Professor Arunima Sen  

Thursday 9th December

Just like we take panoramas on our phones, we use the ROV’s HD camera to take overlapping photos to get a composite picture of life at the oil seeps we are targeting. Each image comes with precise navigation data, so our mosaics are not just pretty pictures, but also georeferenced maps that can be used for scientific and statistical purposes. 

Looking for a needle in a haystack

Text and picture by   Dr Vincent Carrier  

Friday 10th December

Microbes are ubiquitous on Earth: they are inside of you, on you, in your room and every time you swim you touch simultaneously thousands of them at the same time. On the picture above is one of the sediment core the microbiologists onboard has been taken. Only the microbes at the very thin surface of this core likely outnumber largely the entire population of Norway! Yet in seeping areas such as Hopendjupet we are particularly interested in a selection of them. So how do we find so tiny living organisms in a world filled with them? 

Microbiologists rely on two key elements: 

1) A multi-disciplinary team composed of geologists, oceanographers, and/or geochemists that combine efforts with microbiologists to find clues where these microbes are active: changes in chemical composition, the proximity of hydrocarbon-rich sediments, water mass movements. On this cruise, the microbiology team is recovering several tens samples, and analyzing all of them would be time and financially costly. Thereby, they are working closely with geochemists to determine changes in porewater chemistry, offering clues on which environmental samples to further process. 

2) A large diversity of methods where there is one for each different question to be answered. From microscopy to molecular tools, microbiologists are equipped to determine an exhaustive description of environmental microbial community composition, functions, metabolism, trophic relationships, etc. On this cruise, microbiologists are especially interested in identifying microbial community composition (which microbes are there and how many of them?) and which ones are the most active. Therefore, sediment and water column samples have been taken and subsampled, stored onboard in very cold freezers (down to -80°C) to limit damages to DNA and RNA. Onshore, protocols are followed to extract these and will subsequently be sent for genetic analyses.

Microbes are fascinating! Near the surface they help us breath oxygen and down in the sediments they mitigate climate change by oxidizing vast quantities of methane escaping the seafloor. They are our tiny Avengers!

Arctic sources of greenhouse gases 

Text and picture: Henry Patton

CO2 emissions often dominate the climate discussion. Yet methane is an even more potent greenhouse gas, with a global warming potential 84 times greater than CO2 over a 20-year time frame, and could make or break any actions to curb climate change over the coming decades. An important objective of this cruise therefore is to understand just how much of the methane we see naturally leaking from the Barents Sea floor can traverse through the ~340-m thick water column and into the atmosphere.

Friday 10th December

Through a collaboration with NILU (the Norwegian Institute for Air Research) we have been provided with numerous bulbous cannisters with which to collect air samples during this cruise. The process is quick, and with a quick turn of some screws Monica and Christine (pictured) are able to let the vacuum sealed spheres suck in some air within a matter of seconds. To avoid any possible contamination with fumes coming from the ship, we have been collecting these samples from the ship's bow while its nose points into the wind.   

With the screws tightened again these air samples will be analysed later in the lab back onshore, where we hope to find out just how well the ocean can buffer this leakage, and how varied the methane concentrations are across this Arctic setting.

Arctic worms

Text by Arunima Sen

Video by Mariana Esteves

Saturday 11th December

Arctic seeps look like black meadows, but it's worms, not grass that dominates the landscape. Bacteria that use seeping fluids to make food provide the worms with all the nutrition they need so that they don’t need to eat anything. These highly self-sufficient worms are also great mothers: they brood their larvae in their tubes till they are ready to fend for themselves (video).

Santa's robot arm

Text and picture by   Clea Fabian  

Saturday 11th December

It seems that Santa got a robot arm this year. A continuously up and down keeps us very busy in the onboard laboratory. 

Thanks to the crew and all the support we keep the level up. 

Dancing lights in the sky

Text and picture by Mariana Esteves

Sunday 12th December

Having a research cruise in December and in the midst of the polar night, can come with it's own unique challenges, from stormy weather to cold working conditions. However, it can also come with moments of complete awe, such as Friday nights Aurora Borealis display. 

As the whole sky danced with tones of green and purple, the night shift scientists were able to enjoy this private light show from the bow of the ship, R/V G.O.Sars.

The Aurora Borealis, or the Northern Lights, are a natural light display resulting from magnetic disturbances in the atmosphere caused by solar winds. When the charged solar wind particles collide with the atoms and molecules in the Earth's upper atmosphere they become excited and are deflected towards the North and South pole due to the Earth's magnetic field, creating auroral rings. Once the atoms and molecules begin to return to their original state, they emit distinctive colours of light. The colours differ according to the type of atom and molecule present. Oxygen emits either a red-orange or yellow-green glow. Diatomic nitrogen emits a deep red glow, while the ionised form emits a deep blue/purple glow. During intense geomagnetic storms, you can often see many of these colours at once.

Along with the Aurora, we saw many shooting stars and satellites passing overhead. Perhaps even the International Space Station.

Deep Sea Chess

Text and picture by PhD Candidate   Marie Stetzler  

Sunday 12th December

The ROV’s lights illuminate the black and white patterned checkerboards mounted on a frame which has been positioned on the seafloor at ca 340 m depth. No, this year’s world’s chess championship has not been moved to the central Barents Sea, even though some rock fish attracted be the light seem eager for a game. Rather, these will help us understand gas seepage from the seafloor.

Marine gas seeps are quite versatile. Beside their flux intensity, the seepage can also vary between different hydrocarbon compositions. The amount of fluid escaping the subsurface, the gas’ distribution in the water column: all this can be found out by observing the properties of rising bubbles. This led us to design the “checkerboard experiment”, a frame equipped with light, a hydrophone and cameras, and a checkerboard as a scale, putting the spotlight on the seeps. Since the seeping activity in this area is quite intense, we managed to set the frame over three bubble streams at once, each one behaving differently and giving us an idea of how versatile they are and potentially their impact on the water column can be. 

 What was a lucky, very efficient sampling strategy is also fitting for today: it is the third Sunday of Advent, for which the Norwegian custom is to light up three candles. For me, these three deep sea seeps in a frame are just as festive as three candles on a wreath.

A twelve-year dream came true

Text and photo by Dr  Mauro Pau  

Monday 13th December

A twelve-year dream has come true during this cruise. I spent quite a few years of my life studying seabed pockmarks, which are circular topographic depressions occurring in the millions in certain areas. They are formed by the release of fluids through soft sediments. Here in the Barents Sea, pockmarks are evidence for of the release of massive quantities of methane at the inception of the last deglaciation, some 15,000 years ago. They are still there, virtually barren of recent sediments notwithstanding the fact that they are mostly relict features.

It turns out I had never seen the interior of a pockmark. So when our underwater robot casually swam across one of these seabed depressions, for me it was a very special moment. A whole ecosystem was there, from bacterial mats to large cod, based on the synthesis of methane as a primary energy source. There were even shrimps bubble bathing in the seeps. Although what we were seeing is generally related to an active seep site, so not necessarily to the pockmarks that formed in the past, we were in one of them. We even ended up collecting our sediment cores there.

Photo: Cruise participants stare at the live video from the ROV, 340 m below us. Clockwise from left: André Jensen, Karina Weiler, Rune Mattingsdal, Jochen Knies, Vincent Carrier, Arunima Sen.

Perks of sailing with the G.O.Sars

Text and picture by Masters Student Karina Weiler

Tuesday 14th December

Working 12-hour shifts on a research vessel in the middle of the Barents Sea during the Polar Night can be very tough. But the G.O Sars offers a variety of possibilities to get a clear head and relax after a long shift like going to the on-board gym and sauna, feasting on the amazing buffet three times a day and yummy baked goods in the afternoon, enjoying a ride in the massage chair or relaxing in your cabin while viewing the ROV adventures on your TV. It is also really nice to enjoy the outdoors on deck, watching the beautiful colors of daylight, that resemble those of dusk in the southern sky at noon, or the fascinating Northern Lights during the night. When the snow sticks on the deck you can also build a little Olaf, if 'you wanna build a snowman' ☃️.

Working with the CTD

Text and picture by PhD candidate   Christine Tømmervik Kollsgård  

Wednesday 15th December

I’ve been lucky to get to join this exciting cruise, now coming to an end, to the Barents Sea amongst positive and enthusiastic CAGE-researchers. During the 7 days that we spent at the superstations, I helped PhD-student Marie Stetzler collect data for her and others' projects. The main sampling method that I helped with were CTD water sampling.

 CTD stands for conductivity, temperature and depth, thus the sensors we lower through the water column can give information of salinity, density, and temperature of the water masses below. The CTD has 12 water bottles called ‘Niskin’-bottles that are attached and can be fired at different water depths to sample the water from specific points in the water column. Once back on the boat, water samples were taken from the niskin bottles. These samples will be analysed for methane-, nutrients, organic carbon- and δ18O-content. All of the samples will later be used to measure the variations in the water column related to the natural release of methane from the seafloor.

 Luckily, we only had waves at the beginning and end of the cruise during the transits, and during the first CTD station. The photo above is from the first day when the CTD was being deployed and the waves were crashing into the boat and hangar. As soon as the CTD was back on deck, the door was shut so keep us dry while sampling.

Successful polar night cruise

Text by Monica Winsborrow

Thursday 16th December

A December cruise could have been pretty tough. We could be returning to Tromsø with memories of rough seas, darkness, and sea sickness. But instead, we return with memories of amazing images of the seafloor 300m below us and the northern lights and shooting stars above us. Good weather, the professional team of ROV pilots and the impressive crew on G.O.Sars has meant that we have been able to collect far more data than we ever dared hope when planning this cruise. Our luxury problem now is finding enough boxes to pack all of the samples and enough hard drives for all the data. 

But none of this would have been possible without the people that have been on board with us. So we want to say a huge thank you to all the scientists who have joined us on this Polar night adventure. Thank you so much for your expertise, your enthusiasm, your cooperation, and most important of all your tireless good humour. It really has been a pleasure sailing with you.  

And thank you to everyone who has followed our journey. We wish you all a Merry Christmas and a healthy and happy 2022. 

A big thank you to the crew, cruise participants and our readers!

Text by Mariana Esteves

Picture by Mariana Esteves/Bjørn Runar Olsen

Thursday 16th December

As we enter the calm waters of the fjords heading towards Tromsø, and sail past the sleepy towns of northern Norway, I would like to take this opportunity to say thank you!

Thank you to the G.O.Sars Crew, UiB ROV Pilots, and the scientists on board, for marking this a wonderful and successful cruise.

Thank you to the scientists who contributed to the blog and social media.

And a big thank you to our readers, for following our polar night adventure. It has been a pleasure to share with you our journey.

Photo of cruise participants (Left to right): Mariana Esteves, Christine Tømmervik Kollsgård, Clea Fabian, Rune Mattingsdal, Vincent Carrier, Marie Stetzler, Jochen Knies, Karina Weiler, Arunima Sen, Monica Winsborrow, Mauro Pau, Andre Jensen, and Henry Patton.