Expedition in Sunnmøre to discover cold-water corals
Cold-water corals form vulberable and important habitats, particularly in the Norwegian fjords, where our understanding of them and their whereabouts remains limited. In early October 2022, researchers from Runde Research and Møreforsking embarked on an expedition in Søre Sunnmøre to map these corals. At Blueye, we were intrigued by their use of the Blueye ROV for this exploration and reached out to biologist Ørjan S. Vabø for insights.
Vabø is a marine biologist educated at the University of Bergen. Since 2022, he has been working at Runde Research, where he specializes in mapping marine habitats and nature types. He focuses mainly on vulnerable ecosystems such as coral reefs and eelgrass meadows. His work also encompasses studying the communities within and around these habitats.
At Runde Research, Vabø is involved in various projects, including hydrographic, chemical and biological environmental assessments, and monitoring. Additionally, Runde Research monitors plankton blooms and conducts a wide range of other marine research activities. This diverse and dynamic work significantly contributes to understanding and preserving marine environments.
Importance of mapping cold-water corals
Understanding the location of cold-water corals and other marine habitats is crucial for effective ocean management. These ecosystems are significant promoters of biodiversity due to their complex three-dimensional structures, which provides shelter for various species. Moreover, these structures disrupt currents, trapping nutrients and creating nutrient-rich oases. Consequently, knowing their locations is vital to avoid damaging them during fjord management, which is a primary focus of Runde Research's work.
It is also essential to understand the vulnerability of these ecosystems to human activities, especially in the context of climate change, which can lower their tolerance thresholds. Corals in Norwegian fjords grow only about two to ten millimeters per year, making them particularly vulnerable. Damage to these corals can have lasting effects. For instance, a four-meter-high coral reef could be thousands of years old, and its vitality depends on the topmost layer, which is the part of the reef that is "alive". If this layer is harmed, the entire reef could be compromised.
Understanding the location of cold-water corals on the seabed is crucial, as these delicate habitats are highly susceptible to mechanical damage from activities like trawling, anchoring, net setting, and pollution from marine industries. By mapping these habitats with the Blueye ROV, Runde Research can ensure their protections and sustain the biodiversity they support.
What is so special about cold-water corals?
While most people are familiar with tropcial coral reefs, which rely on a symbiotic relationship with algae called zooxanthellae for nutrients through photosynthesis, corals in Norway are found in deeper waters and do not share this symbiosis. For example, in Trondheimsfjorden, corals can be found at depths of about 35 to 38 meters, but generally, they thrive at depths of 130 meters or more. These cold-water corals use their tentacles to feed, capturing food particles carried by ocean currents and from marine snow (organic matter from the surface waters).
Corals are colonial animals (some can be solitary as well) composed of numerous small polyps equipped with tentacles. These tentacles catch food, much like an upside-down jellyfish, as corals belong to the same phylum, Cnidaria, as jellyfish.
Norway is home to some of the largest cold-water coral reefs in the world, primarily consisting of the species Desmophyllum pertusum, formerly known as Lophelia pertusa. This places a significant responsibility on us to protect these reefs and ensure their preservation. By understanding and respecting these delicate ecosystems, we can avoid damaging them and maintain the biodiversity.
We have a really big commitment to taking care of these corals and making sure we do not destroy them." - Ørjan S. Vabø, Marine Biologist, Runde Forsking.
Blueye ROV contributes to finding corals
To locate corals, Runde Research and Møreforsking has utilized the Blueye underwater drone, starting with detailed marine base maps to identify potential coral habitats. In Søre Sunnmøre, these maps provide high-resolution seafloor imagery with one-meter resolution and detailed sediment data. This allows them to focus their mapping efforts on promising areas, particularly targeting hard seafloors regions while excluding soft-bottom areas, and vice versa when looking for sea pens, another type of coral.
Using the Blueye ROV, Runde Research has explored depths up to 230 meters, conducting transects from the seabed to the surface to search for corals. In addition to corals, they also study other vital habitats and species, including sponges and other unique organisms found in our beautiful fjords.
They have also researched areas around Smøla to map regions with cold-water cauliflower coral, known locally as blomkålkorall along with Møreforsking and local divers. Divers often engage in public research, diving along ridges to find these corals, which are typically found at around 30 meters depth. However, their dive time is limited, making the Blueye ROV invaluable for extending the search and examining larger areas for longer periods.
The Blueye ROV has proven beneficial for deep dives and for exploring shallower waters, such as 30 meters and even 0-8 meters, where Runde Research has been investigating seagrass meadows. This technology significantly enhances their ability to study and protect these diverse marine environments.
Although they are a great resource for research purposes, divers can only be down at a limited amount of time and at limited depths. And that is when the Blueye comes in to be able to look at bigger areas for a longer amount of time." - Ørjan S. Vabø, Marine Biologist, Runde Forsking.
Blueye ROV collecting data on the occurrence of cold-water corals
So far, Runde Research has been collecting data on the occurrence of cold-water corals to study the species inhabiting the coral-created habitats and determine their depth range and environmental drivers in Rovdefjord and Storfjord. While fishermen occasionally found corals in their nets, the abundance of corals was largely unknown.
Using the Blueye ROV, they confirmed the widespread distribution of corals throughout the fjords. This discovery, in addition to place coral habitats on maps for easier management, has provided valuable data and insight into various environmental variables that can help identify potential coral habitats through modelling. For instance, Runde Research now has additional information on the depth, slopes and terrain types where corals thrive and detailed sediment types, which are crucial for future modelling efforts. In addition, models providing current speed and current regimes can be extracted on the localities where corals were observed, giving information on these conditions as well.
These findings enable Runde Research to make more precise estimates and improve their ability to locate corals before conducting fieldwork. By refining their methods and expanding their knowledge, they can enhance their understanding and protection of these important marine ecosystems.
By using the Blueye ROV we got to go out and actually confirm there was a lot of corals distributed in the whole fjord." - Ørjan S. Vabø, Marine Biologist, Runde Forsking.
Cost-effective coral mapping by using a Blueye ROV
Runde Research has been utilizing the Blueye ROV for their coral mapping efforts. Prior to using it, Runde Research had heard positive reviews about Blueye, particularly its ease of use. A meeting with Blueye representatives provided them with a thorough introduction to its operation, prompting them to try it out for their mapping needs.
Traditionally, conducting a comprehensive survey to locate corals can cost several hundred thousands Norwegian kroner. However, Runde Research significantly reduced its expenses by using the Blueye ROV. The Blueye ROV offers a cost-effective solution for identifying coral occurrences at depths up to 250 meters. This approach strikes a good balance between cost and data quality, making the Blueye ROV an efficient tool for their research.
We have heard good things about Blueye before, and people said that it was easy to drive." - Ørjan S. Vabø, Marine Biologist, Runde Forsking.
Ease of use and versatility of the Blueye ROV
Vabø says that using the Blueye ROV was remarkably simple, even for someone without prior experience. It is easy to set up and operate, with user-friendly features like auto-heading to maintain direction. This function proved particularly useful when Runde Research was navigating up the steep sides of fjord ridges.
Runde Research used a 300-meter cable, which set their depth limit, but following the fjord ridges with the Blueye ROV was not an issue when the weather was nic, and currents were weak. Additionally, they could maneuver the ROV along the seafloor while following along with the boat, making the process seamless.
Overall, they have been very satisfied with the Blueye ROV's performance and ease of use for their research needs.
We have been happy with how the ROV has been performing." - Ørjan S. Vabø, Marine Biologist, Runde Forsking.
Next steps in research
Runde Research aims to expand their mapping of natural habitats, focusing on vulnerable areas and monitoring environmental conditions. This include studying how the distribution of common species in shallow and deep waters change due to environmental factors. They also plan to conduct more experimental research on vulnerable ecosystems, monitoring their response to human influence and climate change. This is a crucial area of interest for Runde Research.
The Blueye ROV can ba an invaluable tool in these efforts, aiding direct habitat mapping and experimental research. Runde Research looks forward to utilizing their capabilities to further their understanding and protection of marine environments.