Sea ice as a habitat for Bacteria, Archaea and viruses

Deming, Jody W.; Collins, R. Eric

doi:10.1002/9781118778371.ch13

Cited by 33 publications

(34 citation statements)

References 132 publications

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“…A number of cold-adapted bacterial species possess multiple copies of one or more of these mechanosensitive channels, including Colwellia psychrerythraea 34H (MscS), Psychrobacter arcticus (MscS and MscL), and Psychroflexus torquis (MscS and MscL) (Ewert Sarmiento, 2013). The expression of this survival mechanism by the cold-adapted gammaproteobacteria we examined (Figure 9) may help to explain the dominance of this group of bacteria in natural sea-ice communities (Deming and Collins, 2016).…”

Section: Figure 10mentioning

confidence: 96%

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Firth

Carpenter

Sørensen

et al. 2016

Elementa: Science of the Anthropocene

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Bacteria within the brine network of sea ice experience temperature-driven fluctuations in salinity on both short and long temporal scales, yet their means of osmoprotection against such fluctuations is poorly understood. One mechanism used to withstand the ion fluxes caused by salinity shifts, well-known in mesophilic bacteria, is the import and export of low molecular weight organic solutes that are compatible with intracellular functions. Working with the marine psychrophilic gammaproteobacterium, Colwellia psychrerythraea 34H, and with natural microbial assemblages present in sackhole brines drained from sea ice in Kanajorsuit Bay (2013) and Kobbefjord (2014), Greenland, we measured the utilization of 14 C-choline (precursor to glycine betaine, a common compatible solute) at −1°C upon salinity shifts to double and to half the starting salinity. In all cases and across a range of starting salinities, when salinity was increased, 14 C-solute (choline or derivatives) was preferentially retained as an intracellular osmolyte; when salinity was decreased, 14 C-choline was preferentially respired to 14 CO 2 . Additional experiments with cold-adapted bacteria in culture indicated that an abrupt downshift in salinity prompted rapid (subsecond) expulsion of retained 14 C-solute, but that uptake of 14 C-choline and solute retention resumed when salinity was returned to starting value. Overall, the results indicate that bacteria in sea-ice brines use compatible solutes for osmoprotection, transporting, storing and cycling these molecules as needed to withstand naturally occurring salinity shifts and persist through the seasons. Because choline and many commonly used compatible solutes contain nitrogen, we suggest that when brines freshen and bacteria respire such compatible solutes, the corresponding regeneration of ammonium may enhance specific biogeochemical processes in the ice, possibly algal productivity but particularly nitrification. Measurements of potential nitrification rates in parallel sea-ice samples are consistent with a link between use of the compatible solute strategy and nitrification.

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Section: Figure 10mentioning

confidence: 96%

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Firth

Carpenter

Sørensen

et al. 2016

Elementa: Science of the Anthropocene

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“…In the ice‐covered waters of the Southern Ocean, for example, sea‐ice algae may contribute up to 25% of the annual primary production (Arrigo and Thomas ), providing a critical food source for juvenile and sub‐adult krill (Kottmeier and Sullivan , O'Brien ). Within the brine networks of sea ice, 20–30% of this algal primary production is cycled through heterotrophic bacteria, creating complex microbial interactions within the ice (Staley and Gosink , Stewart and Fritsen , Deming and Collins ). The major primary producers in this microbial ecosystem are sea‐ice diatoms (Arrigo and Thomas ).…”

mentioning

confidence: 99%

Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms¹

Torstensson

Young

Carlson

et al. 2019

Journal of Phycology

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Wide salinity ranges experienced during the seasonal freeze and melt of sea ice likely constrain many biological processes. Microorganisms generally protect against fluctuating salinities through the uptake, production, and release of compatible solutes. Little is known, however, about the use or fate of glycine betaine (GBT hereafter), one of the most common compatible solutes, in sea‐ice diatoms confronted with shifts in salinity. We quantified intracellular concentrations and used [14C]‐labeled compounds to track the uptake and fate of the nitrogen‐containing osmolyte GBT and its precursor choline in three Antarctic sea‐ice diatoms Nitzschia lecointei, Navicula cf. perminuta, and Fragilariopsis cylindrus at −1°C. Experiments show that these diatoms have effective transporters for GBT, but take up lesser amounts of choline. Neither compound was respired. Uptake of GBT protected cells against hyperosmotic shock and corresponded with reduced production of extracellular polysaccharides in N. lecointei cells, which released 85% of the retained GBT following hypoosmotic shock. The ability of sea‐ice diatoms to rapidly scavenge and release compatible solutes is likely an important strategy for survival during steep fluctuations in salinity. The release and recycling of compatible solutes may play an important role in algal–bacterial interactions and nitrogen cycling within the semi‐enclosed brines of sea ice.

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“…However, most studies are biased toward sampling in summer and spring, but a few studies in winter indicate differences in communities (Collins et al 2010). On the operational taxonomic unit (OTU) level (97% cutoff), there seem to be no endemic species for sea ice in certain ice zones so far (reviewed by Deming and Collins 2017), but further studies focusing on strain variability may find differences. It has been shown that the bacterial OTUs are more variable in seasonal sea ice and more related to temperate communities compared to MYI (Hatam et al 2016).…”

Section: Bacteriamentioning

confidence: 99%

“…This process is thought to select for sticky bacteria, diatoms and organisms attached to larger organisms or particles (Grossmann and Dieckmann 1994;Weissenberger and Grossmann 1998). Another concentration process is the brine exclusion during the ice formation, concentrating nutrients, salts, and organisms in small and densely packed brine channels (reviewed by Deming and Collins 2017). The brine channels are very rich in nutrients and organic matter but may limit bacterial and algal activities at low temperatures and high salinities, which may fluctuate greatly.…”

Section: Autumnmentioning

confidence: 99%

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Progress in Microbial Ecology in Ice-Covered Seas

Vonnahme

Dietrich

Hassett

2019

YOUMARES 9 - The Oceans: Our Research, Our Future

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Sea ice seasonally covers 10% of the earth's oceans and shapes global ocean chemistry. The unique physical processes associated with sea ice growth and development shape the associated biological diversity and ecosystem function. Microbes make up the base of all marine food webs and the overwhelming majority of biomass in the sea ice ecosystem. Despite their biomass, microbial processes are not fully integrated into marine ecosystem models. Recent applications of novel molecular biology technologies to studies of marine ecology have elucidated numerous microbial-mediated processes interfaced by previously unknown organisms and processes. These discoveries are yielding more in-depth studies on the relevance of mixotrophy, the ecology of fungi, and the interplay between major microbial clades. In ecosystem studies, the basis of the food web is frequently neglected even though the accessibility of energy, recycling of nutrients, and parasitism are crucial factors shaping the environment for grazers and higher trophic levels. In this review, we focus on the species composition, abundance, and functions of microalgae, bacteria, archaea, fungi, and viruses in the sea ice-covered seas throughout the year. A strong emphasis will be put on advances in molecular methods that empower scientists to further investigate microorganisms in more detail. Since microbes make up the majority of all oceanic biomass, we believe that it is impossible to accurately forecast the biological fate of polar marine ecosystems without placing a proportional emphasis on microbes relative to their biomass.

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Sea ice as a habitat for Bacteria, Archaea and viruses

Cited by 33 publications

References 132 publications

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms¹

Progress in Microbial Ecology in Ice-Covered Seas

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Sea ice as a habitat for Bacteria, Archaea and viruses

Cited by 33 publications

References 132 publications

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Bacterial use of choline to tolerate salinity shifts in sea-ice brines

Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms1

Progress in Microbial Ecology in Ice-Covered Seas

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Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms¹