Deep penetration of kelps offshore along the west coast of Greenland

• Published in: Frontiers in Marine Science
• Main Authors: Krause-Jensen, Dorte, Sejr, Mikael K., Bruhn, Annette, Rasmussen, Michael B., Christensen, Peter Bondo, Hansen, Jørgen L.S., Duarte, Carlos M., Bruntse, Grethe, Wegeberg, Susse
• Other Authors: Biological and Environmental Sciences and Engineering (BESE) Division, Marine Science Program, Marine Science and Engineering, Red Sea Research Center, Red Sea Research Center (RSRC), Department of Bioscience, Arctic Research Centre, Aarhus University, Aarhus, Denmark, Department of Bioscience, Aarhus University, Silkeborg, Denmark, Department of Bioscience, Aarhus University, Roskilde, Denmark, Tønder Kommune, Tønder, Denmark
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2019
• Subjects: macroalgae; Saccharina; Agarum; submerged vegetation; depth extension; Arctic; Disko Bay; Greenland; Greenland Institute of Natural Resources; polar night
• Online Access: http://hdl.handle.net/10754/656213; https://doi.org/10.3389/fmars.2019.00375

Until recently, Arctic kelp forests were so understudied that they did not even appear in global kelp forest maps. An increasing focus on Arctic coastal ecosystems has documented extended kelp forests along Arctic coastlines but the distribution of the forests is still not well documented and opens up for surprises. Here, we report kelp depth limits deeper than 61 m (median: 38.4 m, 10-90% percentiles: 10.8-54.4 m) in the Disko Bay region, Greenland, at latitudes of 67-70°N. We compiled, for comparison, existing records of kelp depth limits in high latitude (50°N) regions (median: 17.7 m, 10-90% percentiles: 9.0-38.1 m), which underline that the Disko Bay kelps hold a depth-record for this region. The deepest kelps were located at offshore sites beyond the Disko Island and the main coast. The clear waters offshore with euphotic zones (1% of surface irradiance) extending to 67 m depth provide, along with deep rocky seafloors and low density of sea urchins, the basis for these deep kelps. The sites were ice-covered for 77-133 days year-1, which is beyond the length of the polar night (30-60 days year-1) in the region, suggesting a potential for further depth penetration of kelp forests in a future with longer open water periods and more light potentially reaching the seafloor. This study was a contribution to the Northeast Greenland Environmental Study Program, a collaboration between the Danish Centre for Environment and Energy (DCE, Aarhus University), the Greenland Institute of Natural Resources, and the Environmental Agency for Mineral Resource Activities of the Government of Greenland. Oil companies operating in Greenland are obliged to contribute to knowledge regarding environmental matters. The Strategic Environmental Impact Assessment and the background study program are funded under these commitments administered by the Mineral License and Safety Authority and the Environmental Agency for Mineral Resource Activities. The study was also a contribution to the Greenland Ecosystem Monitoring Program ...