02601nas a2200241 4500008004100000022001400041245005900055210005400114260001200168520187700180653001302057653001902070653001702089653001502106653003102121100001702152700002102169700002602190700002302216700003302239700001702272856007002289 2024 eng d a0030-129900aThe underground network: Facilitation in soil bacteria0 aunderground network Facilitation in soil bacteria c06/20243 a

Our understanding of the fundamental role that soil bacteria play in the structure and functioning of Earth's ecosystems is ever expanding, but insight into the nature of interactions within these bacterial communities remains rudimentary. Bacterial facilitation may enhance the establishment, growth, and succession of eukaryotic biota, elevating the complexity and diversity of the entire soil community and thereby modulating multiple ecosystem functions. Global climate change often alters soil bacterial community composition, which, in turn, impacts other dependent biota. However, the impact of climate change on facilitation within bacterial communities remains poorly understood even though it may have important cascading consequences for entire ecosystems. The wealth of metagenomic data currently being generated gives community ecologists the ability to investigate bacterial facilitation in the natural world and how it affects ecological systems responses to climate change. Here, we review current evidence demonstrating the importance of facilitation in promoting emergent properties such as community diversity, ecosystem functioning, and resilience to climate change in soil bacterial communities. We show that a synthesis is currently missing between the abundant data, newly developed models and a coherent ecological framework that addresses these emergent properties. We highlight that including phylogenetic information, the physicochemical environment, and species-specific ecologies can improve our ability to infer interactions in natural soil communities. Following these recommendations, studies on bacterial facilitation will be an important piece of the puzzle to understand the consequences of global change on ecological communities and a model to advance our understanding of facilitation in complex communities more generally.

10abacteria10aclimate change10afacilitation10aresilience10astress-gradient hypothesis1 aJorna, Jesse1 aAdams, Byron, J.1 aAanderud, Zachary, T.1 aFrandsen, Paul, B.1 aTakacs-Vesbach, Cristina, D.1 aKéfi, Sonia uhttps://nsojournals.onlinelibrary.wiley.com/doi/10.1111/oik.1029902770nas a2200241 4500008004100000245007200041210006900113260001200182300000800194490000700202520208300209653001502292653001902307653001902326653001302345653002202358653002102380100002902401700002002430700001302450700002102463856004402484 2023 eng d00aTemperature response of metabolic activity of an Antarctic nematode0 aTemperature response of metabolic activity of an Antarctic nemat c01/2023 a1090 v123 a

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.

10aAntarctica10acarbon cycling10aclimate change10anematode10arespiration rates10asoil temperature1 aRobinson, Colin, Michael1 aHansen, Lee, D.1 aXue, Xia1 aAdams, Byron, J. uhttps://www.mdpi.com/2079-7737/12/1/10903115nas a2200517 4500008004100000245008300041210006900124260001200193520161800205653001501823653002101838653002601859653001901885653001301904653001701917653002401934653002301958653001701981653001201998100001702010700001802027700002202045700002102067700002002088700003002108700002102138700002402159700002102183700002302204700001502227700001802242700002102260700002302281700002202304700002002326700002302346700002402369700001602393700002302409700002402432700002102456700001902477700001802496700002002514856006302534 2021 eng d00aAntarctic ecosystems in transition – life between stresses and opportunities0 aAntarctic ecosystems in transition life between stresses and opp c06/20213 a

Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder‐relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed‐dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of ‘scientific understanding’ revealed an intermediate level for most of the more detailed sub‐messages, indicating that process‐oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services.

10aadaptation10abenthic dynamism10abiogeochemical cycles10aclimate change10ainvasion10anew habitats10aocean acidification10aPrimary production10arange shifts10asea ice1 aGutt, Julian1 aIsla, Enrique1 aXavier, José, C.1 aAdams, Byron, J.1 aAhn, In‐Young1 aCheng, C.‐H., Christina1 aColesie, Claudia1 aCummings, Vonda, J.1 adi Prisco, Guido1 aGriffiths, Huw, J.1 aHawes, Ian1 aHogg, Ian, D.1 aMcIntyre, Trevor1 aMeiners, Klaus, M.1 aPearce, David, A.1 aPeck, Lloyd, S.1 aPiepenburg, Dieter1 aReisinger, Ryan, R.1 aSaba, Grace1 aSchloss, Irene, R.1 aSignori, Camila, N.1 aSmith, Craig, R.1 aVacchi, Marino1 aVerde, Cinzia1 aWall, Diana, H. uhttps://onlinelibrary.wiley.com/doi/full/10.1111/brv.12679