@article {4840, title = {Temperature response of metabolic activity of an Antarctic nematode}, journal = {Biology}, volume = {12}, year = {2023}, month = {01/2023}, pages = {109}, abstract = {

Because of climate change, the McMurdo Dry Valleys of Antarctica (MCM) have experienced an increase in the frequency and magnitude of summer pulse warming and surface ice and snow melting events. In response to these environmental changes, some nematode species in the MCM have experienced steady population declines over the last three decades, but Plectus murrayi, a mesophilic nematode species, has responded with a steady increase in range and abundance. To determine how P. murrayi responds to increasing temperatures, we measured metabolic heat and CO2 production rates and calculated O2 consumption rates as a function of temperature at 5 \°C intervals from 5 to 50 \°C. Heat, CO2 production, and O2 consumption rates increase approximately exponentially up to 40 \°C, a temperature never experienced in their polar habitat. Metabolic rates decline rapidly above 40 \°C and are irreversibly lost at 50 \°C due to thermal stress and mortality. Caenorhabditis elegans, a much more widespread nematode that is found in more temperate environments reaches peak metabolic heat rate at just 27 \°C, above which it experiences high mortality due to thermal stress. At temperatures from 10 to 40 \°C, P. murrayi produces about 6 times more CO2 than the O2 it consumes, a respiratory quotient indicative of either acetogenesis or de novo lipogenesis. No potential acetogenic microbes were identified in the P. murrayi microbiome, suggesting that P. murrayi is producing increased CO2 as a byproduct of de novo lipogenesis. This phenomenon, in conjunction with increased summer temperatures in their polar habitat, will likely lead to increased demand for carbon and subsequent increases in CO2 production, population abundance, and range expansion. If such changes are not concomitant with increased carbon inputs, we predict the MCM soil ecosystems will experience dramatic declines in functional and taxonomic diversity.

}, keywords = {LTER-MCM, Antarctica, carbon cycling, climate change, nematode, respiration rates, soil temperature}, doi = {10.3390/biology12010109}, url = {https://www.mdpi.com/2079-7737/12/1/109}, author = {Robinson, Colin Michael and Hansen, Lee D. and Xue, Xia and Adams, Byron J.} } @article {4735, title = {Ten scientific messages on risks and opportunities for life in the Antarctic}, year = {2022}, month = {02/2022}, institution = {Antarctic Environments Portal}, abstract = {

Initiated by the SCAR scientific research programme \“Antarctic Thresholds \– Ecosystem Resilience and Adaptation\” (AnT-ERA, 2013-2021), 26 experts synthesized knowledge on impacts and risks of climate-change on biological processes and ecosystem functions in the Antarctic. The ten main scientific messages that emerged addressed (1) accelerating marine and terrestrial biogeochemical cycles, (2) response to ocean acidification, (3) ecological changes in climate change hot spots, (4) unexpected dynamism of marine seafloor communities, (5) biodiversity shifts, (6) low temperature limitation of protein synthesis, (7) life intrinsically linked to changing sea ice conditions, (8) pollution, (9) genetically distinct terrestrial populations under threat, and (10) newly discovered habitats. Two-thirds of the literature included in this synthesis was published between 2010 and 2020 and only one-third was published earlier. The fast mounting, recent decadal evidence indicates various Antarctic biological communities now experience climate stress, or will experience such stress in the coming decades. The responses of organisms, ecosystem functions and services to environmental changes are complex and varied. Key knowledge gaps remain and need addressing to adequately assess future prospects for life in the Antarctic.

}, keywords = {LTER-MCM}, url = {https://environments.aq/publications/ten-scientific-messages-on-risks-and-opportunities-for-life-in-the-antarctic/}, author = {Gutt, Julian and Isla, Enrique and Xavier, Jos{\'e} C. and Adams, Byron J. and Ahn, In-Young and Cheng, C.-H. Christina and Colesie, Claudia and Cummings, Vonda J. and Griffiths, Huw J. and Hogg, Ian D. and McIntyre, Trevor and Meiners, Klaus M. and Pearce, David A. and Lloyd S. Peck and Piepenburg, Dieter and Reisinger, Ryan R. and Saba, Grace and Schloss, Irene R. and Signori, Camila N. and Smith, Craig R. and Vacchi, Marino and Verde, Cinzia and Diana H. Wall} }