Microbes in the
Anthropocene
Kathryn Forcone, Natascha Varona, Linhao Xu
What are microbes?
Bacteria, Fungi, Viruses, Arcea, Protists
Some fun facts:
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Some tasks include: nitrogen fixation, nutrient cycling,
oxygen synthesis, maintain symbiotic relationships,
cause/control of disease ect …
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The microbes on Earth would outnumber all the other
flora and fauna on Earth--and outweigh them as well.
Your body is composed of 10 trillion human cells, but is
host to around 100 trillion bacterial cells. Your body
bacteria cells outnumber your own human cells ten to
one
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(source: https://microbe.med.umich.edu/some-interesting-facts-missing-microbes)
Credit: Silveiralab
Microbes in the Anthropocene
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Humans focused on creating sterile areas - disrupting natural populations and
inadvertently selecting strains for resistance (Sariola and Gilbert, 2020)
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Microbial expansion and virulence, high density urban areas, COVID19
Lateral gene transfer in bacteria causes deadly, rapidly evolving populations Selection by antibiotics, disinfectants, and heavy metals.
First discovery and isolation of Penicillin from mold in WWII lead to a ramp-up in
global production of antibiotics and decreased mortality from Pneumonia and Staph
infections. People then started adding antibiotics to animals to promote faster growth
and less disease.
Wastewater, Sewage, Hospitals: Bacterial
antibiotic resistance
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High use of antibiotics contributes to global
antibiotic resistant bacteria
Hospital wastewater and drinking water help
spread drug resistant bacteria into surrounding
environments
○ One study from 222 water samples
showed all isolated gram-negative
bacteria resistant to amoxicillin and
ampicillin (Koudokpon et al., 2021)
○ Dispersal is associated with improper
waste disposal containing contaminants
○ (Tong et al., 2009) Antibiotic resistance in
wastewater from swine farms
Wastewater, Sewage, Hospitals: Bacterial
antibiotic resistance
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Surface soil ecosystems spread
antibiotic resistance from ground,
surface and wastewater.
Anthropogenic contaminants seep
into ground
Antibiotic resistance genes and
mobile genetic elements correlate
with heavy metals in the soil (Wang
et al., 2021, Zhao et al., 2019)
Global warming-Arbuscular mycorrhizal fungi( AMF)
Wilson et al. 2016
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Arbuscular mycorrhizal fungi (AMF) are plant mutualists in the subphylum
Glomeromycotina of Mucoromycota.
AMF can increase plant fitness and benefit ecological restoration.
However, global warming in the anthropocene directly decreased AMF colonization, which
would dampen plant community and ecosystem.
Anthropogenic soil degradation-AMF
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AMF density and richness are lower in
degraded areas than in reference sites.
Degraded areas have low potassium (K)
concentration and high levels of clay and
metals.
Low AMF compositions in the degraded
sites greatly decrease plant fitness.
Box-plots of AMF (a) density and (b) richness
Coutinho et al. 2019
Anthropogenic pollution (nitrogen deposition)-AMF
Allen et al. 2016
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AMF colonization is higher in plants grown in non-polluted soils than in polluted areas.
Nitrogen deposition decreased AMF activity.
Root colonization declined from 45% to 19%, and spore density declined from 105 to 23 spores with
elevated N.
Microbialization of the oceans
Haas et al. 2016
Microbialization of the oceans
DDAM model (Dissolved organic carbon, disease, algae, microbes)
Anthropogenic agents
leading to
microbializaition:
● Overfishing
● Agricultural
runoff
● Anthropogenic
climate change
Nelson and Altieri, 2019
Microbialization leads to an increase in
bacteriophages infecting microbes
(Knowles et al. 2016)
What next?
Citations
Tong, Lei, Ping Li, Yanxin Wang, and Kuanzheng Zhu. 2009. “Analysis of Veterinary Antibiotic Residues in Swine Wastewater and Environmental Water Samples Using Optimized SPE-LC/MS/MS.” Chemosphere
74 (8): 1090–97.
https://doi.org/10.1016/j.chemosphere.2008.10.051.
Wang, Xiaomin, Bangrui Lan, Hexin Fei, Shanyun Wang, and Guibing Zhu. 2021. “Heavy Metal Could Drive Co-Selection of Antibiotic Resistance in Terrestrial Subsurface Soils.” Journal of Hazardous Materials
411 (June): 124848.
https://doi.org/10.1016/j.jhazmat.2020.124848.
Zhao, Yi, Tatiana Cocerva, Siobhan Cox, Stacie Tardif, Jian-Qiang Su, Yong-Guan Zhu, and Kristian Koefoed Brandt. 2019. “Evidence for
Co-Selection of Antibiotic Resistance Genes and Mobile Genetic Elements in Metal Polluted Urban Soils.” Science of The
Total Environment 656 (March): 512–20. https://doi.org/10.1016/j.scitotenv.2018.11.372.
Barott, K.L., and Rohwer, F.L. (2012) Unseen players shape benthic competition on coral reefs. Trends Microbiol 20: 621–628
Dinsdale EA, Rohwer F. Fish or germs? Microbial dynamics associated with changing trophic structures on coral reefs. In: Coral Reefs: An Ecosystem in Transition. Springer Netherlands;
2011:231-240. doi:10.1007/978-94-007-0114-4_16
Haas AF, Fairoz MFM, Kelly LW, et al. Global microbialization of coral reefs. Nat Microbiol. 2016;1(6):1-7. doi:10.1038/nmicrobiol.2016.42
Jessen C, Roder C, Villa Lizcano JF, Voolstra CR, Wild C. In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the
Central Red Sea. Fulton C, ed. PLoS One. 2013;8(6):e66992. doi:10.1371/journal.pone.0066992
Knowles B, Silveira CB, Bailey BA, et al. Lytic to temperate switching of viral communities. Nature. 2016;531(7595):466-470. doi:10.1038/nature17193
Roach TNF, Abieri ML, George EE, et al. Microbial bioenergetics of coral-algal interactions. PeerJ. 2017;2017(6):e3423. doi:10.7717/peerj.3423
Nelson HR, Altieri AH. Oxygen: the universal currency on coral reefs. Coral Reefs. 2019;38(2):177-198. doi:10.1007/s00338-019-01765-0
Silveira CB, Coutinho FH, Cavalcanti GS, et al. Genomic and ecological attributes of marine bacteriophages encoding bacterial virulence genes. BMC Genomics. 2020;21(1):126.
doi:10.1186/s12864-020-6523-2
Some interesting facts from "missing Microbes". (n.d.). Retrieved March 30, 2021, from https://microbe.med.umich.edu/some-interesting-facts-missing-microbes