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By sampling Northwest Atlantic deep-sea basins, the expedition IceDivA II aims to extend the previous Northeast Atlantic deep-sea programs, IceAGE (Icelandic marine Animals: Genetics and Ecology) and IceDivA (Icelandic marine Animals meets Diversity along latitudinal gradients in the deep sea of the Atlantic Ocean), also linking with the South Atlantic deep-sea programme DIVA (Latitudinal Gradients in BioDIVersity in the deep Atlantic) and those in the Southern Ocean. This will provide pan-Atlantic deep-sea samples to investigate topics regarding species richness and evolution. To map the species diversity, and answer questions on the connectivity of deep-sea fauna along latitudinal gradients in the pan-Atlantic Ocean, we will sample in 3,000 m to 5,500 m water depths from the Icelandic Basin, via the Labrador Basin, to the Newfoundland Basin, bridging the NW Atlantic knowledge gap between prior expeditions. The faunal analysis will follow an integrative approach, combining modern genomic methods with traditional, morphological taxonomy. Via cooperative data/sample sharing we will support the BMBF project PLASTISEA as well as the EU projects iAtlantic and HOTMIC.
On 8 January 2021, a team of 21 scientists aboard the German research vessel Sonne will set out on the IceDivA expedition (SO280) in the Atlantic to study the diversity of marine organisms in the deep sea. They intend to collect samples from the Iceland Basin to the Azores at depths between 4,000 and 5,000 meters and map the ocean floor by means of hydroacoustics. To date, the deep-sea ecosystem has been studied less extensively than the far side of the moon. The team hopes that the IceDivA expedition will contribute to a better understanding of the deep-sea biome, ultimately leading to more efficient conservation measures.
The primary focus of the IceDivA expedition is to study the distribution of deep-sea species. In this context, IceDivA can build on the findings of several preceding projects – the end point of the previous expedition IceAGE3 (SO276 in the summer of 2020) defines the starting point of this new expedition. The integration of data from previous missions forms a central component of the IceDivA work, with comparable and consistent use of equipment and standardized sampling techniques making it possible to evaluate paradigms regarding biodiversity, species inventory, and species composition in relation to depth and width.
The IceDivA expedition connects two deep-sea projects in this regard: IceAGE (Icelandic marine Animals: Genetics and Ecology) and DIVA (Latitudinal Gradients in BioDIVersity in the deep Atlantic) as well as the EU project iAtlantic. IceAGE is an established international project that was initiated in 2011 and builds on the preceding project BIOICE (Benthic Invertebrates of Icelandic Waters). By connecting to the southernmost IceAGE3 station, IceDivA adds a latitudinal gradient, which in turn forms a link to the BIODIAZ project (Controls in benthic and pelagic BIODIversity of the AZores). The study area is located in one of iAtlantic’s regions of interest (the Porcupine deep-sea plain and the Azores plateau). A contiguous and comprehensive mapping of the ocean floor by means of hydroacoustics is an indispensable prerequisite for identifying habitats – one of the iAtlantic project’s primary tasks, and an equally important objective in the IceDivA project.
In addition to the biological studies, the “DArgo2025_RBRpilot” project will also be on board. As part of this project, a total of 10 ARGO floats made by different manufacturers will be equipped with sensors for measuring the salinity, temperature and pressure (CTD) to compare their respective performance. Breaking with the traditional approach, on this expedition the floats will be released as a swarm in a single position, if possible, to obtain an initial direct comparison of the measuring parameters. Concurrently, the water column in the release area will be examined at a fine scale with onboard CTD sensors. These measurements serve as a reference for assessing the ARGO float data. During the course of the expedition on RV Sonne, after their successful release, the floats will repeatedly dive to depths of 2,000 meters and return to the surface 48 hours later to transmit the collected data via satellite to a data centre.
The IceAGE3 expedition, carried out as part of the IceAGE project, will use the latest marine technology to explore, map and sample a variety of deep-sea ecosystems, ranging from spectacular cold-water coral gardens on the Icelandic shelf, to the chemical-dependent fauna of hydrothermal vents at the mid-Atlantic ridge, and the myriad of creatures that are adapted to inhabit the deep ocean. The overall aim is to understand better the connections between the different habitats and ecosystems found within the Atlantic around Iceland.
Key areas of investigation include better understanding of the genetic, morphological, and environmental patterns in Atlantic ecosystems and habitats, and the correlation and relationships between them. Larger issues under investigation are related to the different Atlantic water masses: the deep waters around Iceland include boreal, subarctic, and Arctic zones that hold discrete bodies of water, which allow scientists to compare the deep-sea ecosystems that are found in different locations. How much variation exists between basins in the deep sea? Is there gene flow between deep-sea basins? Do we see the same patterns in the deep sea and the continental shelf?
After leaving port in Emden on 22 June 2020, the RV Sonne will travel northwards to the Norwegian Basin, where the team will start their sampling in waters more than 4000 m deep. Cruising towards the gradually shallower waters of the Icelandic shelf (up to 800 m water depth), the team will explore the habitats and inhabitants of the abyssal plain, including cold-water coral gardens that are expected to be seen along the thermocline in approximately 900 m water depth. The team will use multibeam bathymetric mapping to make a detailed map of the seafloor, before using the Remotely Operated Vehicle ROV Kiel 6000 to dive down and explore targeted areas – the ROV is equipped with high-definition cameras, and we hope to livestream footage from the seafloor back to scientists and colleagues back on land.
Next, we will cross the Iceland-Faroe Ridge to fill in the gaps in a map of a large coral reef known as “Lóndsjúp”, located on the shelf break south of Iceland, and also revisit some sample locations from previous expeditions. From here, the ship will continue along the Reykjanes Ridge – the portion of the mid-Atlantic Ridge just south of Iceland – to find and investigate the hydrothermal vent site that IceAGE scientists expect to find there from looking at existing mapping data.
Finally, for the third and final part of the expedition, RV Sonne will sail southwards into gradually deeper waters, examining the changes in conditions and ecosystems along the way, finishing in the Iceland Basin at more than >4500m water depth.
The RV Sonne is home to a team of 34 German participants, who have responsibility for making sure the ROV and other equipment is working well. The expedition is led by deep-sea biologist Dr Saskia Brix, who is based at Institute SENCKENBERG am Meer (German Center for Marine Biodiversity Research, DZMB). With her and the Senckenberg team are colleagues from a range of other German institutions, including GEOMAR, MARUM, CeNak, BSH, University of Hamburg, Oldenburg and Hannover as well as Goethe University Frankfurt, who bring expertise in biodiversity, marine geology, physical oceanography.
Nearly all marine science cruises have been postponed during the coronavirus pandemic, with most research vessels returning back to their home ports. However, with careful preparation and planning, this expedition – which, due to international travel restrictions, is carrying only German researchers instead of the planned international IceAGE team – was able to go ahead. The whole crew has been working from home offices for 2 weeks and then confined in quarantine for 3 days before departure, with meticulous testing of everyone for COVID-19 before boarding the ship. The ship’s medical facility is equipped with virus testing equipment, and everyone on board will observe strict hygiene measures, including allowing only single occupancy of cabins – something of a luxury for a research vessel!
The team on board RV Sonne will be sending daily updates from the ship via a cruise blog – our primary blogger-on-board is geoscientist and seafloor mapping expert Mia Schumacher from GEOMAR. To follow the blog, see the links at the bottom of the page – from here you can follow all the action from the ship, find out what how marine scientists take samples from the seafloor thousands of metres below the ship, and read about life on board a research ship. We will also bring you footage from the ROV as it explores the deep-sea world, and there will be opportunities to ask the science team questions and (internet connection permitting!) engage in some live chat with the team on board. You can also follow progress via Twitter @IceAGE_RR, Instagram and Facebook (both @SenckenbergWorld).
Livestream from the ROV Kiel 6000 on selected dives is available to watch at www.youtube.com/senckenbergworld