title: Comparing springtime ice-algal chlorophyll a and physical properties of multi-year and first-year sea ice from the Lincoln Sea.
abstract: With near-complete replacement of Arctic multi-year ice (MYI) by first-year ice (FYI) predicted to occur within this century, it remains uncertain how the loss of MYI will impact the abundance and distribution of sea ice associated algae. In this study we compare the chlorophyll a (chl a) concentrations and physical properties of MYI and FYI from the Lincoln Sea during 3 spring seasons (2010-2012). Cores were analysed for texture, salinity, and chl a. We identified annual growth layers for 7 of 11 MYI cores and found no significant differences in chl a concentration between the bottom first-year-ice portions of MYI, upper old-ice portions of MYI, and FYI cores. Overall, the maximum chl a concentrations were observed at the bottom of young FYI. However, there were no significant differences in chl a concentrations between MYI and FYI. This suggests little or no change in algal biomass with a shift from MYI to FYI and that the spatial extent and regional variability of refrozen leads and younger FYI will likely be key factors governing future changes in Arctic sea ice algal biomass. Bottom-integrated chl a concentrations showed negative logistic relationships with snow depth and bulk (snow plus ice) integrated extinction coefficients; indicating a strong influence of snow cover in controlling bottom ice algal biomass. The maximum bottom MYI chl a concentration was observed in a hummock, representing the thickest ice with lowest snow depth of this study. Hence, in this and other studies MYI chl a biomass may be under-estimated due to an under-representation of thick MYI (e.g., hummocks), which typically have a relatively thin snowpack allowing for increased light transmission. Therefore, we suggest the on-going loss of MYI in the Arctic Ocean may have a larger impact on ice-associated production than generally assumed.
authors.affiliation: Polar Biological Oceanography, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany; University of Hamburg, Centre for Natural History (CeNak), Zoological Museum, Biocenter Grindel, Hamburg, Germany; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Lange
authors.affiliation: Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Michel
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Justin F
authors.initials: JF
authors.lastname: Beckers
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: J Alec
authors.initials: JA
authors.lastname: Casey
authors.affiliation: Polar Biological Oceanography, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany; University of Hamburg, Centre for Natural History (CeNak), Zoological Museum, Biocenter Grindel, Hamburg, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Flores
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Ido
authors.initials: I
authors.lastname: Hatam
authors.affiliation: Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Meisterhans
authors.affiliation: Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Niemi
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada; Department of Earth and Space Sciences and Engineering, York University, Toronto, Ontario, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Haas
mesh_terms: D001110:Arctic Regions; D002170:Canada; D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D056890:Eukaryota / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D046448:Ice Cover; D012621:Seasons; D012623:Seawater; D012914:Snow / Q000737:chemistry
chemical_list: D002734:Chlorophyll; D000077194:Chlorophyll A