Antarctic Sea Ice--a Habitat for Extremophiles

Thomas, David N.; Dieckmann, Gerhard

doi:10.1126/science.1063391

Cited by 567 publications

(386 citation statements)

References 38 publications

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“…The limited acclimation period of 72 h was designed to probe the species responses to short-term fluctuations in temperature and salinity levels known to occur within the sea-ice matrix (Thomas and Dieckmann, 2002). The results showed that C. simplex cells from the pelagic treatment (salinity 35 and 5°C) had the highest cellular carbon, protein, energy content and the greatest rates of carbon production (Figures 3 and 4).…”

Section: Discussionmentioning

confidence: 99%

Snapshot prediction of carbon productivity, carbon and protein content in a Southern Ocean diatom using FTIR spectroscopy

et al. 2015

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Diatoms, an important group of phytoplankton, bloom annually in the Southern Ocean, covering thousands of square kilometers and dominating the region's phytoplankton communities. In their role as the major food source to marine grazers, diatoms supply carbon, nutrients and energy to the Southern Ocean food web. Prevailing environmental conditions influence diatom phenotypic traits (for example, photophysiology, macromolecular composition and morphology), which in turn affect the transfer of energy, carbon and nutrients to grazers and higher trophic levels, as well as oceanic biogeochemical cycles. The paucity of phenotypic data on Southern Ocean phytoplankton limits our understanding of the ecosystem and how it may respond to future environmental change. Here we used a novel approach to create a 'snapshot' of cell phenotype. Using mass spectrometry, we measured nitrogen (a proxy for protein), total carbon and carbon-13 enrichment (carbon productivity), then used this data to build spectroscopy-based predictive models. The models were used to provide phenotypic data for samples from a third sample set. Importantly, this approach enabled the first ever rate determination of carbon productivity from a single time point, circumventing the need for timeseries measurements. This study showed that Chaetoceros simplex was less productive and had lower protein and carbon content during short-term periods of high salinity. Applying this new phenomics approach to natural phytoplankton samples could provide valuable insight into understanding phytoplankton productivity and function in the marine system.

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Section: Discussionmentioning

confidence: 99%

Snapshot prediction of carbon productivity, carbon and protein content in a Southern Ocean diatom using FTIR spectroscopy

et al. 2015

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“…3). In the sea ice, phytoplankton are incorporated into the ice matrix, and are exposed to freezing, hypersaline conditions within the brine channels (Thomas and Dieckmann, 2002) as well as low light or complete darkness for several months of the year. In the MIZ, productivity is generally high, due to the stable, nutrient rich, sun-drenched conditions and lower salinity from the melt-ing ice (Fig.…”

Section: So Phytoplankton Physiology: Responses To Global Changementioning

confidence: 99%

Southern Ocean phytoplankton physiology in a changing climate

Petrou

Kranz

Trimborn

et al. 2016

Journal of Plant Physiology

104

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Please cite this article in press as: Petrou, K., et al., Southern Ocean phytoplankton physiology in a changing climate. J Plant Physiol (2016), http://dx.doi.org/10.1016/j.jplph.2016.05.004 ARTICLE IN PRESS a b s t r a c tThe Southern Ocean (SO) is a major sink for anthropogenic atmospheric carbon dioxide (CO 2 ), potentially harbouring even greater potential for additional sequestration of CO 2 through enhanced phytoplankton productivity. In the SO, primary productivity is primarily driven by bottom up processes (physical and chemical conditions) which are spatially and temporally heterogeneous. Due to a paucity of trace metals (such as iron) and high variability in light, much of the SO is characterised by an ecological paradox of high macronutrient concentrations yet uncharacteristically low chlorophyll concentrations. It is expected that with increased anthropogenic CO 2 emissions and the coincident warming, the major physical and chemical process that govern the SO will alter, influencing the biological capacity and functioning of the ecosystem. This review focuses on the SO primary producers and the bottom up processes that underpin their health and productivity. It looks at the major physico-chemical drivers of change in the SO, and based on current physiological knowledge, explores how these changes will likely manifest in phytoplankton, specifically, what are the physiological changes and floristic shifts that are likely to ensue and how this may translate into changes in the carbon sink capacity, net primary productivity and functionality of the SO.

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“…Extensive research has documented species composition and distribution of extremophilic communities (Ferris and Ward, 1997;Pace, 1997;Ward et al, 1998) and the specific adaptations that enable growth at extreme conditions, such as specialized lipid membranes and use of novel enzymes (Thomas and Dieckmann, 2002;van den Burg, 2003;Macalady et al, 2004). However, it has also been shown that extremophiles must invest a fraction of their energy and metabolic resources to maintain correctly folded proteins, osmotic homeostasis, and to detoxify radical chemical species (Kawakami et al, 2004;Baker-Austin et al, 2005;Ram et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Cultivation and quantitative proteomic analyses of acidophilic microbial communities

et al. 2009

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Acid mine drainage (AMD), an extreme environment characterized by low pH and high metal concentrations, can support dense acidophilic microbial biofilm communities that rely on chemoautotrophic production based on iron oxidation. Field determined production rates indicate that, despite the extreme conditions, these communities are sufficiently well adapted to their habitats to achieve primary production rates comparable to those of microbial communities occurring in some non-extreme environments. To enable laboratory studies of growth, production and ecology of AMD microbial communities, a culturing system was designed to reproduce natural biofilms, including organisms recalcitrant to cultivation. A comprehensive metabolic labeling-based quantitative proteomic analysis was used to verify that natural and laboratory communities were comparable at the functional level. Results confirmed that the composition and core metabolic activities of laboratory-grown communities were similar to a natural community, including the presence of active, low abundance bacteria and archaea that have not yet been isolated. However, laboratory growth rates were slow compared with natural communities, and this correlated with increased abundance of stress response proteins for the dominant bacteria in laboratory communities. Modification of cultivation conditions reduced the abundance of stress response proteins and increased laboratory community growth rates. The research presented here represents the first description of the application of a metabolic labeling-based quantitative proteomic analysis at the community level and resulted in a model microbial community system ideal for testing physiological and ecological hypotheses.

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Antarctic Sea Ice--a Habitat for Extremophiles

Cited by 567 publications

References 38 publications

Snapshot prediction of carbon productivity, carbon and protein content in a Southern Ocean diatom using FTIR spectroscopy

Snapshot prediction of carbon productivity, carbon and protein content in a Southern Ocean diatom using FTIR spectroscopy

Southern Ocean phytoplankton physiology in a changing climate

Cultivation and quantitative proteomic analyses of acidophilic microbial communities

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