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Climatic and temporal control on microbial diversity-ecosystem functioning: insights from a novel conceptual model (CLIMIFUN).

Periodic Reporting for period 2 - CLIMIFUN (Climatic and temporal control on microbial diversity-ecosystem functioning: insights from a novel conceptual model (CLIMIFUN).)

Reporting period: 2018-08-01 to 2019-07-31

Despite the importance of soil microbial communities for ecosystem functioning and human welfare, little is known about the mechanisms controlling the biodiversity of these communities, and the role of their attributes in regulating key ecosystem processes such as nutrient cycling. Many studies have identified the ecological drivers of plant and animal diversity. However, much less is known about the interactive effects of multiple ecological drivers (e.g. climate, soil properties etc) in regulating microbial diversity and ecosystem attributes. This lack of knowledge hampers our ability to predict microbial community shifts and their consequences for ecosystem functioning under climate change, and limits the inclusion of soil microbes in global biogeochemical models.

The main research objective of this action is to gain a deeper insight into the global patterns and mechanisms that drive soil microbial diversity and ecosystem processes under changing environments. We are using a novel conceptual framework combining multiple ecological predictors, climate change experiments and structural equation modelling to quantitatively evaluate the role of the multiple ecological drivers of microbial diversity and ecosystem processes. The research outlined in this proposal includes a range of state-of-the-art biochemical, molecular and genomic methods for the analysis of microbial communities and ecosystem processes that ensure the maximum utility and impact of our results. Altogether, CLIMIFUN will reveal the factors that control soil microbial diversity and key ecosystem processes (e.g. nutrient cycling) under changing environments. This work will thus address a key knowledge gap relevant to supporting increases in global demand for food and fiber over the next decades, and a research priority for H2020.
CLIMIFUN have led to the first global atlas of dominant bacterial taxa. Here, we showed that only 2% of bacterial phylotypes (~500 phylotypes) consistently accounted for almost half of the soil bacterial communities worldwide. Despite the overwhelming diversity of bacterial communities, relatively few bacterial taxa are abundant in soils globally. We clustered these dominant taxa into ecological groups to build the first global atlas of soil bacterial taxa, published in Science in January (Delgado-Baquerizo et al. 2018. Science 359: 320–325). A major breakthrough of this study is that habitat preferences are not predictable from phylum-level identity alone, given that all of the ecological clusters included phylotypes from multiple phyla. By narrowing down the number of phylotypes to be targeted in future studies from tens of thousands to a few hundred, our study paves the way for a more predictive understanding of soil bacterial communities, which is critical for accurately forecasting the ecological consequences of ongoing global environmental change.

CLIMIFUN has investigated the changes in soil biodiversity during ecosystem development (PNAS, 2019). Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower productivity ecosystems (drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity share similar ecological drivers as soils and ecosystems develop. Together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally-distributed ecosystem types, and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia. 

CLIMIFUN has also provided the first global assessment of the environmental factors controlling the priming effect (Nature Communications, 2019). Our work showed that the magnitude of the positive apparent priming effect (increase in CO2 release through accelerated microbial biomass turnover) was negatively associated with SOC content and microbial respiration rates. Our statistical modeling suggests that apparent priming effects tend to be negative in more mesic sites associated with higher SOC contents. In contrast, a single-input of labile C causes positive apparent priming effects in more arid locations with low SOC contents. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.

CLIMIFUN also investigated the importance of microbial communities as predictor of multifunctionality resistance (C, N and P cycling) to climate change and nitrogen fertilization. This work was published in Ecology Letters in September 2017 (Delgado-Baquerizo et al. 2017. Ecology Letters 20: 1295–1305).
So far, CLIMIFUN has led to multiple communication and dissemination items. The results from CLIMIFUN have been disseminated in multiple international conferences including (1) Biocrust3. Third International Workshop on Biological Soil Crusts. Arizona, USA (September 2016), (2) 2nd Global Soil Biodiversity Conference. Nanjing, China (October 2017, Keynote speaker) and (3) the international conferences: e.g. MEDECOS XIV International Conference & XIII AEET Meeting, Sevilla (January 2017). CLIMIFUN has also delivered informal talks to citizens.

Results from CLIMIFUN are constantly being advertised at Twitter (https://twitter.com/ManuDelBaq). Moreover, CLIMIFUN have resulted in multiple media items including radio shows (e.g. http://cienciaes.com/entrevistas/2018/02/23/mapa-mundial-de-bacterias/ and https://www.srf.ch/sendungen/wissenschaftsmagazin/forscher-erobern-den-sendeturm-beromuenster) and media press releases having a strong impact in the media in Europe and elsewhere (e.g. ABC, https://www.abc.es/ciencia/abci-crean-primer-mapa-global-universo-bacterias-suelos-tierra-201801182022_noticia.html El País https://elpais.com/elpais/2018/01/18/ciencia/1516289742_174723.html OPB, https://www.opb.org/news/article/npr-scientists-peek-inside-the-black-box-of-soil-microbes-to-learn-their-secrets/ NPR, https://www.npr.org/sections/thesalt/2018/01/18/578924748/scientists-peek-inside-the-black-box-of-soil-microbes-to-learn-their-secrets?utm_medium=RSS&utm_campaign=storiesfromnpr to name a few).

The results from CLIMIFUN have also been discussed in the international and prestigious blog of Nature Ecology and Evolution: https://natureecoevocommunity.nature.com/users/58180-manuel-delgado-baquerizo.
Finally, the scientific work derived from CLIMIFUN is available online via https://zenodo.org/search?page=1&size=20&q=delgado-baquerizo and open access journals such as Science Advances (e.g. http://advances.sciencemag.org/content/3/4/e1602008).
During its last year, CLIMIFUN will evaluate the effects of induced climate change on microbial communities and ecosystem processes in ecosystems from the Iberian peninsula, which will will yield significant new insights on the mechanisms driving soil biodiversity and ecosystem processes under climate change scenarios.
Canary Islands (Spain)
Colorado (USA)
Colorado (USA)