scholarly journals Selective incorporation of dissolved organic matter (DOM) during sea ice formation

2013 ◽  
Vol 155 ◽  
pp. 148-157 ◽  
Author(s):  
Susann Müller ◽  
Anssi V. Vähätalo ◽  
Colin A. Stedmon ◽  
Mats A. Granskog ◽  
Louiza Norman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Ice Formation ◽  
Selective Incorporation

scholarly journals Behaviour of dissolved organic matter and inorganic nutrients during experimental sea-ice formation

2001 ◽  
Vol 33 ◽  
pp. 317-321 ◽  
Author(s):  
Virginia Giannelli ◽  
David N. Thomas ◽  
Christian Haas ◽  
Gerhard Kattner ◽  
Hilary Kennedy ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Organic Compounds ◽  
Sea Water ◽  
Ice Cores ◽  
Inorganic Nutrients ◽  
Ice Formation ◽  
Solid Matrix ◽  
Dissolved Organic Compounds

AbstractIt is well established that during sea-ice formation, crystals aggregate into a solid matrix, and dissolved sea-water constituents, including inorganic nutrients, are rejected from the ice matrix. However, the behaviour of dissolved organic matter (DOM) during ice formation and growth has not been studied to date. DOM is the primary energetic substrate for microbial heterotrophic activity in sea water and sea ice, and therefore it is at the base of the trophic fluxes within the microbial food web. The aim of our study was to compare the behaviour of DOM and inorganic nutrients during formation and growth of sea ice. Experiments were conducted in a large indoor ice-tank facility (Hamburg Ship Model Basin, Germany) at −15°C. Three 1 m3 tanks, to which synthetic sea water, nutrients and dissolved organic compounds (diatom-extracted DOM) had been added, were sampled over a period of 5 days during sea-ice formation. Samples were collected throughout the experiment from water underlying the ice, and at the end from the ice as well. Brine was obtained from the ice by centrifuging ice cores. Inorganic nutrients (nitrate and phosphate) were substantially enriched in brine in comparison to water and ice phases, consistent with the processes of ice formation and brine rejection. Dissolved organic carbon (DOC) was also enriched in brine but was more variable and enriched in comparison to a dilution line. No difference in bacteria numbers was observed between water, ice and brine. No bacteria growth was measured, and this therefore had no influence on the measurable DOC levels. We conclude that the incorporation of dissolved organic compounds in newly forming ice is conservative. However, since the proportions of DOC in the brine were partially higher than those of the inorganic nutrients, concentrating effects of DOC in brine might be different compared to salts.

scholarly journals Bacterial community dynamics and activity in relation to dissolved organic matter availability during sea‐ice formation in a mesocosm experiment

2014 ◽  
Vol 3 (1) ◽  
pp. 139-156 ◽  
Author(s):  
Eeva Eronen‐Rasimus ◽  
Hermanni Kaartokallio ◽  
Christina Lyra ◽  
Riitta Autio ◽  
Harri Kuosa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Bacterial Community ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Community Dynamics ◽  
Mesocosm Experiment ◽  
Ice Formation ◽  
Bacterial Community Dynamics

Changes in the composition and bioavailability of dissolved organic matter during sea ice formation

2015 ◽  
Vol 60 (3) ◽  
pp. 817-830 ◽  
Author(s):  
Linda Jørgensen ◽  
Colin A. Stedmon ◽  
Hermanni Kaartokallio ◽  
Mathias Middelboe ◽  
David N. Thomas
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Ice Formation

scholarly journals Evidence for significant protein-like dissolved organic matter accumulation in Sea of Okhotsk sea ice

2015 ◽  
Vol 56 (69) ◽  
pp. 1-8 ◽  
Author(s):  
Mats A. Granskog ◽  
Daiki Nomura ◽  
Susann Müller ◽  
Andreas Krell ◽  
Takenobu Toyota ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Surface Waters ◽  
Sea Of Okhotsk ◽  
Sea Water ◽  
First Year ◽  
Ice Melt ◽  
Ultraviolet Range ◽  
Considerable Excess

AbstractAbsorption and fluorescence of chromophoric dissolved organic matter (CDOM) in sea ice and surface waters in the southern Sea of Okhotsk was examined. Sea-water CDOM had featureless absorption increasing exponentially with shorter wavelengths. Sea ice showed distinct absorption peaks in the ultraviolet, especially in younger ice. Older first-year sea ice had relatively flat absorption spectra in the ultraviolet range. Parallel factor analysis (PARAFAC) identified five fluorescent CDOM components, two humic-like and three protein-like. Sea water was largely governed by humic-like fluorescence. In sea ice, protein-like fluorescence was found in considerable excess relative to sea water. The accumulation of protein-like CDOM fluorescence in sea ice is likely a result of biological activity within the ice. Nevertheless, sea ice does not contribute excess CDOM during melt, but the material released will be of different composition than that present in the underlying waters. Thus, at least transiently, the CDOM introduced during sea-ice melt might provide a more labile source of fresher protein-like DOM to surface waters in the southern Sea of Okhotsk.

scholarly journals Dissolved organic matter in Antarctic sea ice

2001 ◽  
Vol 33 ◽  
pp. 297-303 ◽  
Author(s):  
David N. Thomas ◽  
Gerhard Kattner ◽  
Ralph Engbrodt ◽  
Virginia Giannelli ◽  
Hilary Kennedy ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Pore Space ◽  
Ice Cores ◽  
Weddell Sea ◽  
Poor Correlation ◽  
First Year ◽  
Mean Values ◽  
Antarctic Sea Ice

AbstractIt has been hypothesized that there are significant dissolved organic matter (DOM) pools in sea-ice systems, although measurements of DOM in sea ice have only rarely been made. The significance of DOM for ice-based productivity and carbon turnover therefore remains highly speculative. DOM within sea ice from the Amundsen and Bellingshausen Seas, Antarctica, in 1994 and the Weddell Sea, Antarctica, in 1992 and 1997 was investigated. Measurements were made on melted sea-ice sections in 1994 and 1997 and in sea-ice brines in 1992. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations in melted ice cores were up to 1.8 and 0.78 mM, respectively, or 30 and 8 times higher than those in surface water concentrations, respectively. However, when concentrations within the brine channel/pore space were calculated from estimated brine volumes, actual concentrations of DOC in brines were up to 23.3 mM and DON up to 2.2 mM, although mean values were 1.8 and 0.15 mM, respectively. There were higher concentrations of DOM in warm, porous summer second-year sea ice compared with colder autumn first-year ice, consistent with the different biological activity supported within the various ice types. However, in general there was poor correlation between DOC and DON with algal biomass and numbers of bacteria within the ice. The mean DOC/DON ratio was 11, although again values were highly variable, ranging from 3 to highly carbon-enriched samples of 95. Measurements made on a limited dataset showed that carbohydrates constitute on average 35% of the DOC pool, with highly variable contributions of 1−99%.

scholarly journals Characteristics of Chromophoric and Fluorescent Dissolved Organic Matter in the Nordic Seas

2018 ◽  
Author(s):  
Anna Makarewicz ◽  
Piotr Kowalczuk ◽  
Sławomir Sagan ◽  
Mats A. Granskog ◽  
Alexey K. Pavlov ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Chlorophyll A ◽  
Saline Water ◽  
Atlantic Water ◽  
Nordic Seas ◽  
Ice Melt ◽  
Fluorescent Dissolved Organic Matter ◽  
West Spitsbergen

Abstract. Optical properties of Chromophoric (CDOM) and Fluorescent Dissolved Organic Matter (FDOM) were characterized in the Nordic Seas including the West Spitsbergen Shelf during June–July of 2013, 2014 and 2015. The CDOM absorption coefficient at 350 nm, aCDOM(350) showed significant interannual variation. In 2013, the highest average aCDOM(350) values (aCDOM = 0.30 ± 0.12 m−1) were observed due to the influence of cold and low–saline water from the Sørkapp Current in the southern part of West Spitsbergen Shelf. In 2014, aCDOM(350) values were significantly lower than in 2013 (av. aCDOM(350) = 0.14 ± 0.06 m−1), which was associated with the dominance of warm and saline Atlantic Water (AW) in the region, while in 2015 intermediate CDOM absorption (av. aCDOM(350) = 0.19 ± 0.05 m−1) was observed. In situ measurement of three FDOM components revealed that protein–like FDOM dominated and concentration of marine and terrestrial humic–like DOM were very low and its distribution were generally vertically homogenous in the upper ocean (0–100 m). Fluorescence of terrestrial and marine humic–like FDOM decreased in surface waters (0–15 m) near the sea–ice edge by dilution of oceanic waters by sea–ice melt water. The vertical distribution of protein–like FDOM was characterized by a prominent sub–surface maximum that matched the subsurface chlorophyll a maximum and was observed all across the study area. The highest protein–like FDOM fluorescence was observed in the Norwegian Sea in the core of warm AW. There was a significant relationship between the protein–like fluorescence and chlorophyll a fluorescence (R2 = 0.65, p 

scholarly journals Antarctic Bacteria, Sea Ice Ecosystem Dynamics, and Global Climate Change

2021 ◽  
Author(s):  
◽  
Andrew Robert Martin
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Microbial Community ◽  
Dissolved Organic Matter ◽  
Southern Ocean ◽  
Sea Ice ◽  
Metabolic Activity ◽  
Bacterial Response ◽  
Pack Ice ◽  
Fast Ice

<p>Productivity in the Southern Ocean reflects both the spatial and temporal dynamics of the sea ice ecosystem, as well as the complex cycling of energy through the microbial community. Marine bacteria are thought to be integral to trophodynamics and the functioning of a microbial loop within the ice matrix, but there is no clear understanding of the distribution and diversity of bacteria or the importance of bacterial production. Understanding the bacterial response to environmental change in the sea ice ecosystem may provide an insight into the potential changes to the physical oceanography and ecology of the Southern Ocean. In this study, a multivariate statistical approach was used to compare the distribution and abundance of bacteria occurring in pack ice at the tongue of the Mertz Glacier (George V Coast, Antarctica) with bacteria from fast ice at Cape Hallett (Victoria Land coastline, Antarctica). Estimates of bacterial abundance were derived using both epifluorescence microscopy and flow cytometry and correlated with algal and chlorophyll a data. Significant differences in the vertical distribution of cells within the ice were observed between the Mertz Glacier and Cape Hallett, but no overall difference in cell abundance was found between the two locations with 7.6 ± 1.2 x 109 cells per m2 and 8.7 ± 1.6 x 109 cells per m2 respectively. Bacteria and algae were positively correlated in pack ice of the Mertz Glacier indicating a functional microbial loop, but no discernable relationship was exhibited in multiyear ice at Cape Hallett. These findings support the general consensus that the generation of bacterial biomass from algal-derived dissolved organic matter is highly variable across seasons and habitats. The tetrazolium salt 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) was used to investigate the bacterial response to experimentally induced changes in light and salinity in fast ice at Cape Hallett. Two distinct assemblages were examined; the brine channel assemblage near the surface of the ice and the interstitial or bottom assemblage. This study presents preliminary evidence that the metabolic activity of brine bacteria is influenced by light stimulus, most likely as a response to increased levels of algal-derived dissolved organic matter. No cells were deemed to be metabolically active when incubated in the dark, while on average thirty-eight percent of the cells incubated at 150 =mol photons m-2 s-1 were metabolically active. Additional results indicate that salt concentration is more significant than light irradiance in influencing the metabolic response of cells present in the interstitial region of the sea ice profile. When acclimated over a period of eight hours, cells exhibited a tolerance to changing saline concentrations, but after a further eight hours there is some evidence to suggest activity is reduced at either end of the saline regime. Bacterial metabolic activity in each assemblage is thus thought to reflect the fundamentally different light and saline environments within the sea ice. Metabolic probes such as CTC will prove useful in providing a mechanistic understanding of productivity and trophodynamics in the Antarctic coastal ecosystem, and may contribute to prognostic models for qualifying the resilience of the microbial community to climate change.</p>

scholarly journals Production of Chromophoric Dissolved Organic Matter (CDOM) in Laboratory Cultures of Arctic Sea Ice Algae

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 926
Author(s):  
Guiju Li ◽  
Huixiang Xie ◽  
Guisheng Song ◽  
Michel Gosselin
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Chlorophyll A ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Chromophoric Dissolved Organic Matter ◽  
Ice Algae ◽  
Production Rates ◽  
Arctic Sea

Chromophoric dissolved organic matter (CDOM) is highly enriched in bottom sea ice in the Arctic during ice algal blooms, giving rise to multifaceted ecological implications in both the sea ice and the underlying seawater. We conducted laboratory culture incubations to assess the potential role of ice algae in the accumulation of CDOM in Arctic sea ice. Non-axenic monocultures of Attheya septentrionalis and Nitzschia frigida and a natural ice algal assemblage (NIAA) were grown at 4 °C in an f/2 medium under cool white fluorescent light. Culture samples were collected several days apart throughout the exponential, stationary, and senescent phases, and analyzed for CDOM absorbance, chlorophyll a, and bacterial cell abundance. The cultures displayed apparent specific growth rates of algal and bacterial cells comparable to those in the field. Accumulations of CDOM were observed in all cultures during the time-course incubations, with the senescent phase showing the largest accumulations and the highest production rates. The senescent-phase production rate for NIAA was ~40% higher than that for A. septentrionalis. The chlorophyll a-normalized CDOM production rates in the cultures are comparable to those reported for Arctic first-year sea ice. The absorption spectra of CDOM in the cultures exhibited characteristic short-ultraviolet shoulders similar to those previously identified in sea ice. This study demonstrates that ice algal-derived CDOM can account for the springtime accumulation of CDOM in Arctic sea ice.

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