Implications of brine channel geometry and surface area for the interaction of sympagic organisms in Arctic sea ice

Krembs, Christopher; Gradinger, Rolf; Spindler, Michael

doi:10.1016/s0022-0981(99)00111-2

Cited by 149 publications

(106 citation statements)

References 38 publications

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“…Their incorporation in the sea ice matrix and actual transport behaviour depends on several characteristics which are not currently well constrained: (i) whether the particles move actively (e.g., flagellates), (ii) whether the particles are transported passively (by moving brine), (iii) whether and how quickly they stick on the walls of brine inclusions or on other impurities, (iv) whether they can get sealed into the sea ice microstructure. For instance, ice microorganisms combine mobility and attachment onto ice surfaces via the release of EPS and icebinding proteins [Krembs et al, 2000;Becquevort et al, 2009;Juhl et al, 2011;Raymond and Kim, 2012].…”

Section: Particulate Tracersmentioning

confidence: 99%

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Vancoppenolle

Meiners

Michel

et al. 2013

Quaternary Science Reviews

215

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International audienceObservations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas exchanges at the sea ice interface through an often permeable sea ice cover; and (iii) tight physical, biological and chemical interactions between the sea ice, the ocean and the atmosphere. Photosynthetic micro-organisms in sea ice thrive in liquid brine inclusions encased in a pure ice matrix, where they find suitable light and nutrient levels. They extend the production season, provide a winter and early spring food source, and contribute to organic carbon export to depth. Under-ice and ice edge phytoplankton blooms occur when ice retreats, favoured by increasing light, stratification, and by the release of material into the water column. In particular, the release of iron - highly concentrated in sea ice - could have large effects in the iron-limited Southern Ocean. The export of inorganic carbon transport by brine sinking below the mixed layer, calcium carbonate precipitation in sea ice, as well as active ice-atmosphere carbon dioxide (CO₂) fluxes, could play a central role in the marine carbon cycle. Sea ice processes could also significantly contribute to the sulphur cycle through the large production by ice algae of dimethylsulfoniopropionate (DMSP), the precursor of sulphate aerosols, which as cloud condensation nuclei have a potential cooling effect on the planet. Finally, the sea ice zone supports significant ocean-atmosphere methane (CH₄) fluxes, while saline ice surfaces activate springtime atmospheric bromine chemistry, setting ground for tropospheric ozone depletion events observed near both poles. All these mechanisms are generally known, but neither precisely understood nor quantified at large scales. As polar regions are rapidly changing, understanding the large-scale polar marine biogeochemical processes and their future evolution is of high priority. Earth system models should in this context prove essential, but they currently represent sea ice as biologically and chemically inert. Palaeoclimatic proxies are also relevant, in particular the sea ice proxies, inferring past sea ice conditions from glacial and marine sediment core records and providing analogues for future changes. Being highly constrained by marine biogeochemistry, sea ice proxies would not only contribute to but also benefit from a better understanding of polar marine biogeochemical cycles

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Section: Particulate Tracersmentioning

confidence: 99%

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Vancoppenolle

Meiners

Michel

et al. 2013

Quaternary Science Reviews

215

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“…Initially, when seawater freezes, constituent ions are concentrated into so-called brine channels and pockets, which may reach salinities of up to 225 ‰ (Krembs et al 2000). These brines may also differ from the original seawater in ionic composition due to differential precipitation of salts (Assur 1958).…”

Section: Introductionmentioning

confidence: 99%

Characterization and growth response to temperature and salinity of psychrophilic, halotolerant Chlamydomonas sp. ARC isolated from Chukchi Sea ice

Eddie

Krembs

Neuer

2008

Mar. Ecol. Prog. Ser.

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Sea ice provides a habitat for a diverse community of microorganisms, which comprise a substantial portion of primary production in ice-covered seas. Organisms immured in sea ice have to withstand strong changes in temperature and salinity. We report on the growth rate response to salinity and temperature of the chlorophyte Chlamydomonas sp. ARC, isolated from land-fast sea ice in the Chukchi Sea, Alaska. We found it to be a euryhaline psychrophile capable of growth at temperatures as low as -5°C and at salinities from 2.5 to 100 ‰. The maximum growth rate of 0.41 d -1 (± 0.027) was found at 5°C and a salinity of 30 ‰. The salinity growth range of this organism indicates that it is well adapted to the variable salinity environment associated with brine channels in sea ice, as well as the hypotonic conditions associated with melting ice. Based upon morphology and molecular phylogenetic reconstructions using the 18S ribosomal ribonucleic acid (rRNA) gene and the ribulose 1, 5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene, this Arctic Chlamydomonas falls into a distinct clade containing other as yet unassigned psychrophilic Chlamydomonas strains isolated from Arctic and Antarctic environments, pointing to a bi-polar distribution of this clade. It is also very closely related to the brackish water mesophile Chlamydomonas kuwadae Gerloff, and is capable of growth above the psychrophilic range in low-salinity medium, indicating that it may represent an intermediate between mesophilic and psychrophilic lifestyles.KEY WORDS: Chlamydomonas · Chlorophyta · Arctic sea ice · Chukchi Sea · Psychrophile · Euryhaline · Phylogeny 354: 107-117, 2008 temperatures, ice algae growing in the brine channels need to be tolerant of widely varying salinities. Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerIn physiological studies testing the adaptation of Antarctic ice algae to low temperature and high salinity, Bartsch (1989) found that cell division was observed at temperatures as cold as -5.5°C and a salinity of 90 ‰. Aletsee & Jahnke (1992) reported growth of the marine diatoms Nitzschia frigida Grunow and Thalassiosira antarctica Comber at temperatures as low as -8 and -6°C and at salinities of 145 and 109 ‰, respectively. In general, sea-ice diatoms are often euryhaline and thrive in conditions from 10 to 60 ‰ (Grant & Horner 1976).Diatoms have been the focus of most studies on seaice algae, because they are considered the most abundant phototrophs in sea ice (Horner 1985, Lizotte 2003. Green algae are usually a relatively minor component, but the chlorophyte Chlamydomonas spp. has been found repeatedly in Arctic sea ice (see 'Discussion'). Chlamydomonas species may play a disproportionably large role in the initial colonization of sea ice. Weissenberger (1998) found Chlamydomonas sp. to dominate newly formed ice for the first 3 mo in a tank experiment inoculated with an enrichment culture from sea-ice brine. Despite their ubiquity in Arctic sea ice, most ...

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“…A number of sea ice diatom species coexist in the narrow space of brine channels (Krembs et al, 2000). This habitat is characterized by extreme conditions (low light intensities, low temperature, high salinities and limited supply of nutrients) which are strong selection factors for diatom species.…”

Section: Introductionmentioning

confidence: 99%

Photosynthetic energy conversion under extreme conditions—II: the significance of lipids under light limited growth in Antarctic sea ice diatoms

2002

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Low photosynthetic active radiation is a strong determinant in the development and growth of sea ice algae. The algae appear to have universal mechanisms to overcome light limitation. One important process, which is induced under light limitation, is the desaturation of chloroplast membrane lipids. In order to discover whether this process is universally valid in sea ice diatoms, we investigated three species coexisting in chemostats illuminated with 15 and 2 mmol photons m À2 s À1 at À1 C. Growth under 2 mmol photons m À2 s À1 caused a 50% increase in monogalactosyldiacylglycerols (MGDG) thylakoid membrane related 20:5 n-3 fatty acids. This fatty acid supports the fluidity of the thylakoid membrane and therefore the velocity of electron flow, which is indicated by increasing rate constants for the electron transport between Q A (first stable electron acceptor) and bound Q B (second stable electron acceptor) (11.16 AE 1.34 to 23.24 AE 1.35 relative units). Two mmol photons m À2 s À1 furthermore resulted in higher amounts of non-lipid bilayer forming MGDG in relation to other bilayer forming lipids, especially digalactosydiacylglycerol (DGDG). The ratio of MGDG:DGDG increased from 3.4 AE0.3 to 5.7 AE0.3. The existence of bilayer thylakoid membranes with high proportions of non. bilayer forming lipids is only possible when sufficient thylakoid pigment-protein complexes are present. If more thylakoid pigment-protein complexes are present in membranes, as found under extreme light limitation, less bilayer forming lipids such as DGDG are required to stabilize the bilayer structure. Differences in protein contents between both light intensities were not found. Consequently pigment contents which nearly doubled under 2 mmol photons m À2 s À1 must be responsible in balancing the potential stability loss resulting from an increase in MGDG:DGDG ratio. #

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Implications of brine channel geometry and surface area for the interaction of sympagic organisms in Arctic sea ice

Cited by 149 publications

References 38 publications

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Characterization and growth response to temperature and salinity of psychrophilic, halotolerant Chlamydomonas sp. ARC isolated from Chukchi Sea ice

Photosynthetic energy conversion under extreme conditions—II: the significance of lipids under light limited growth in Antarctic sea ice diatoms

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