Deep Penetration of Kelps Offshore Along the West Coast of Greenland

TY - JOUR

T1 - Deep Penetration of Kelps Offshore Along the West Coast of Greenland

AU - Krause-Jensen, Dorte

AU - Sejr, Mikael K.

AU - Bruhn, Annette

AU - Rasmussen, Michael B.

AU - Christensen, Peter Bondo

AU - Hansen, Jørgen L. S.

AU - Duarte, Carlos M.

AU - Bruntse, Grethe

AU - Wegeberg, Susse

PY - 2019

Y1 - 2019

N2 - 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.

AB - 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.

KW - Agarum

KW - Arctic

KW - CARBON

KW - COVE

KW - FJORD

KW - GROWTH

KW - KONGSFJORDEN

KW - MACROALGAE

KW - REFUGIA

KW - SEA

KW - STABILITY

KW - Saccharina

KW - depth extension

KW - macroalgae

KW - submerged vegetation

UR - https://www.scopus.com/pages/publications/85068602855

U2 - 10.3389/fmars.2019.00375

DO - 10.3389/fmars.2019.00375

M3 - Journal article

SN - 2296-7745

VL - 6

JO - Frontiers in Marine Science

JF - Frontiers in Marine Science

IS - JUL

M1 - 375

ER -