Variability of light transmission through Arctic land-fast sea ice during spring

Nicolaus, Marcel; Petrich, Chris; Hudson, Stephen R.; Granskog, Mats A.

doi:10.5194/tc-7-977-2013

Cited by 46 publications

(38 citation statements)

References 45 publications

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“…By combining surface measurements from a sledge-based system (Hudson et al, 2012) with measurements carried out by divers beneath the ice, the complete radiation balance of the first-year sea ice system could be quantified, for a given case and stage . Similar observations were also done over landfast ice near Barrow, Alaska, but with the under-ice radiation measured from a sledge that slides along the underside of the land-fast ice, pulled with a rope (Nicolaus et al, 2013).…”

Section: Transmittance Of Sea Ice and Snowsupporting

confidence: 55%

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

et al. 2014

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Abstract. The Arctic climate system includes numerous highly interactive small-scale physical processes in the atmosphere, sea ice, and ocean. During and since the International Polar Year 2007-2009, significant advances have been made in understanding these processes. Here, these recent advances are reviewed, synthesized, and discussed. In atmospheric physics, the primary advances have been in cloud physics, radiative transfer, mesoscale cyclones, coastal, and fjordic processes as well as in boundary layer processes and surface fluxes. In sea ice and its snow cover, advances have been made in understanding of the surface albedo and its relationships with snow properties, the internal structure of sea ice, the heat and salt transfer in ice, the formation of superimposed ice and snow ice, and the small-scale dynamics of sea ice. For the ocean, significant advances have been related to exchange processes at the ice-ocean interface, diapycnal mixing, double-diffusive convection, tidal currents and diurnal resonance. Despite this recent progress, some of these small-scale physical processes are still not sufficiently understood: these include wave-turbulence interactions in the atmosphere and ocean, the exchange of heat and salt at the ice-ocean interface, and the mechanical weakening of sea ice. Many other processes are reasonably well understood as stand-alone processes but the challenge is to understand their interactions with and impacts and feedbacks on other processes. Uncertainty in the parameterization of small-scale processes continues to be among the greatest challenges facing climate modelling, particularly in high latitudes. Further improvements in parameterization require new year-round field campaigns on the Arctic sea ice, closely combined with satellite remote sensing studies and numerical model experiments.

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Section: Transmittance Of Sea Ice and Snowsupporting

confidence: 55%

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

et al. 2014

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“…Our results demonstrate the strong potential to estimate Antarctic ice algal biomass from transmitted under-ice irradiance spectra, in particular using NDIs. Given some degree of regional dependency for our bestperforming method (NDIs), our results suggest that this method may be more appropriate for time series measurements using moored sensors than multiregional mapping efforts (Nicolaus et al 2013. However, explanatory power might be improved through consideration of additional predictive variables (e.g.…”

Section: Discussionmentioning

confidence: 95%

“…the vertical distribution of ice algal biomass, the biomass of under-ice phytoplankton or the concentration of non-algal particles). Nicolaus et al (2013) found that the seasonal evolution of transmitted solar radiation through landfast sea ice near Barrow, Alaska, USA, exceeded the spatial variability. All 3 of the voyages considered here were carried out early in the season during spring algal biomass buildup.…”

Section: Discussionmentioning

confidence: 99%

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Melbourne-Thomas¹,

Meiners²,

Mundy³

et al. 2015

Mar. Ecol. Prog. Ser.

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The presence of algal pigments in sea ice alters under-ice irradiance spectra, and the relationship between these variables can be used as a non-invasive means for estimating iceassociated algal biomass on ecologically relevant spatial and temporal scales. While the influence of snow cover and ice algal biomass on spectra transmitted through the snow-ice matrix has been examined for the Arctic, it has not been tested for Antarctic sea ice at regional scales. We used paired measurements of sea ice core chl a concentrations and hyperspectral-transmitted under-ice irradiances from 59 sites sampled off East Antarctica and in the Weddell Sea to develop algorithms for estimating algal biomass in Antarctic pack ice. We compared 4 approaches that have been used in various bio-optical studies for marine systems: normalised difference indices, ratios of spectral irradiance, scaled band area and empirical orthogonal functions. The percentage of variance explained by these models ranged from 38 to 79%, with the best-performing approach being normalised difference indices. Given the low concentrations of integrated chl a observed in our study compared with previous studies, our statistical models performed surprisingly well in explaining variability in these concentrations. Our findings provide a basis for future work to develop methods for non-invasive time series measurements and medium-to large-scale spatial mapping of Antarctic ice algal biomass using instrumented underwater vehicles.KEY WORDS: Sea ice algae · Chl a · Bio-optics · Normalised difference index · Weddell Sea · East Antarctica Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 536: [107][108][109][110][111][112][113][114][115][116][117][118][119][120][121] 2015 ice coring (Meiners et al. 2012). Recent circumpolar estimates of ice algal biomass for Antarctica are limited to records from historical ice core data that are unevenly distributed in space and time (Meiners et al. 2012) and model-based estimates that may underestimate internal communities (Saenz & Arrigo 2014). Improved in situ data on temporal and spatial patterns of ice algal biomass distribution are needed for quantitative evaluation of sea ice primary production models and an improved understanding of the role of ice algae in Antarctic marine ecosystem function.Antarctic pack ice provides a habitat for iceassociated algae, which form distinct surface, interior and bottom communities (Arrigo et al. 2010, Meiners et al. 2012. Surface communities are promoted by snow loading, surface flooding by seawater and brine, and subsequent snow-ice formation (Ackley et al. 2008). Interior communities can form either through the rafting and ridging of ice floes or by scavenging of phytoplankton during ice formation (i.e. the uptake of algal cells from the water column as ice crystals form; Arrigo et al. 2010). Bottom communities thrive in the lowermost porous parts of sea ice floes, where brine salinities and high nutrient availability favour algal gr...

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“…The 3 known sinks for DMS are photo-oxidation, bacterial consumption and ventilation. Photooxidation should be minimal underneath the ice due to the prevailing low irradiance in general and UV radiation in particular (Winther et al 2004, Nicolaus et al 2013. DMS bacterial consumption likely takes place, but, as observed at lower latitudes, DMSconsuming bacteria generally take some time to react to a pulse in DMS, allowing a temporary buildup of the DMS reservoir.…”

Section: Response Of the Under-ice Algal And Bacterial Assemblage To mentioning

confidence: 99%

Under-ice microbial dimethylsulfoniopropionate metabolism during the melt period in the Canadian Arctic Archipelago

Galindo¹,

Levasseur²,

Scarratt³

et al. 2015

Mar. Ecol. Prog. Ser.

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This study reports on the temporal variations in algal and bacterial metabolism of dissolved dimethylsulfoniopropionate (DMSPd) in Arctic ice-covered waters in response to the release of organic matter (OM) from the sea ice and the onset of under-ice phytoplankton growth. Sampling took place between 21 May and 21 June 2012 at a station located in Resolute Passage. A snow and ice melt event was accompanied by an important release of OM and total DMSP from the bottom ice to the water column. This input of OM coincided with increases in DMSPd and DMSPd loss rate constant at the ice-water interface and, 2 days later, with increases in DMSPd and bacterial dimethylsulfide (DMS) yields from DMSPd at 0.5 m under the ice. The different microbial responses suggest that DMSPd-rich brines were released first, followed by the release of sympagic algae due to ice melt. In both cases, the changes in DMSPd metabolism resulted in an increase in gross DMS production from 0.15 to 1.9 nmol l −1 d −1. The initiation of phytoplankton growth resulted in increases in bacterial abundance, DMSPd loss-rate constant and DMSP-sulfur assimilation. In contrast, DMS yield remained low during the onset of phytoplankton growth, indicating that bacteria used DMSP as a carbon and sulfur source. These results show that ice DMSPd can be rapidly (<1 d) and efficiently (up to 10%) converted into DMS by bacteria once released in surface water during melt events, a process that could contribute to DMS peaks measured at the ice edge.

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Variability of light transmission through Arctic land-fast sea ice during spring

Cited by 46 publications

References 45 publications

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Under-ice microbial dimethylsulfoniopropionate metabolism during the melt period in the Canadian Arctic Archipelago

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