Ice cores from the Tibetan Plateau reveal bacterial community convergence related to

climate and anthropogenic activity

Yongqin Liu , Tandong Yao , Baiqing Xu

Institute of Tibetan Plateau Research, CAS

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Glaciers on the Tibetan Plateau

Number ： 46298 , Area ： 59406 km2 , Volume ： 5590 km3

Account for ~50% of glacier area in the non-polar region2

Microbe in the Glaciers

Rhodopseudomonas sp. Massilia sp.

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Glacier Glacier

OCEAN

4Average precipitation:279, 392 m, and 797 mm, Temperature: -4.1 ,2.8 and and 12.1 °C

GLDD, NJKS, and ZQP: are surrounded by steppe, meadow, and forests land

Ice core drill decontaminate

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Bacterial abundance

Extract DNA

PCR

454 Pyrasequence

Bacterial community

Chemical analysis

Methods

6Bacterial abundance increased in the past 60 years in all three ice cores

4.3×104 ± 4.7×104

cells mL-1

2.6×104 ± 2.3×104

cells mL-1

1.6×104 ± 0.4×104

cells mL-1

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GLDD NJKS ZQP

edf F P edf F p edf F p

Temperature 0.70 0.62 0.04 0 0 0.78 1.83 0.57 0.09

log(Black Carbon) Data not available 1.05 2.15 0.01 2.27 7.74 <0.001

log(Dust) 3.76 4.39 <0.001 6.05 0.77 0.04 0 0 1.00

India Monsoon 0 0 0.92 2.97 22730 1.00 0.75 0.88 0.03

Time 13.57 8.88 <0.001 3.38 3.11 <0.001 0 0 0.93

Deviation

explained 86% 81% 53%

Time range 1957-2004 1960-2006 1970-2006

Summary of bacterial time-series GAM Regression Model

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Bacterial community composition in different years in three ice cores

GLDD NJKS

ZQP

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Bacterial phylogenetic diversity (Shannon) in different years in three ice cores

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Abundance

Diversity

Bacterial abundance and diversity in three ice cores

Year distance-decay relationship of bacterial communities

diss

imila

rity

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Nonmetric multidimensional scaling of Bray-Curtis dissimilarities at the OTU level in three ice cores over the past 60 years. Note the converging trend after 1990

GLDD ZQP13

Ac

tin

ob

ac

teri

a (

%)

Ba

cte

roid

ete

s (

%)

Major group variation at different years in GLDD and ZQP

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SourceTracker algorithm showing the percentage of the tracked community associated with sequences from regional soils, lake sediments, lake water, and marine water

Soil associated bacterial in GLDD decreased response to the increase of westerly precipitation

(年 )

15

So

il a

sso

cia

ted

b

act

eri

al (

%)

Ac

cu

mu

lati

on

(m

m)

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Ocean source bacteria decreased with the South Asian Monsoon, and soil assosiated

bacteria increased in ZQPS

oil

ass

oc

iate

d

ba

cte

ria

l (%

)

Ma

rin

e a

sso

cia

ted

b

act

eri

al (

%)

SA

M in

dex

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Factors influence bacterial Communities

Mantel test results show the significant factors:

GLDD: Year (r=0.72,p=0.001); Westerly (r=0.22, p=0.05)

ZQP: Year (r=0.59, p=0.001) ;Temperature ( r=0.68,p=0.001);

Black Carbon ( r=0.62, p=0.001); SST (( r=0.44,p=0.003)

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Atmospher ic c i rcula t ion

Prec ip i ta t ion Glaciers

Habi ta t homogenizat ion

Human act iv i ty homogenizat ion

Bacter ia l converage

Conclusion

we report the first high-resolution bacterial records from the last half-century in ice cores collected from three Tibetan Plateau glaciers.

Bacterial abundance, diversity, and community composition among the ice cores was related to geographical location and annual climatic events specific to each glacier.

Despite the broad environmental differences among the three ice cores studied, bacterial community composition in the ice cores converged through time while overall bacterial diversity decreased. Bacterial abundance also increased with the anthropogenic production of black carbon.

These biotic changes are related to increasing air temperature, atmosphere cycle impacts, and anthropogenic activities that have occurred on and around the Plateau during the last half-century.

Thank you!

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