Toxicology Centre
Inferring long-term trends in prairie reservoirs
(Saskatchewan, Canada) through analysis of DNA in
sediment cores
Tse, T. J.a,b, Song, T.a, Hecker, M.a,b, Giesy, J.P.a,b,c, Doig, L. E.a,b, and Jones, P. Da,b,d
aToxicology
Center, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3,
Canada
bGlobal Institute for Water Security, University of Saskatchewan, 11 Innovation Boulevard,
Saskatoon, SK, S7N 3H5, Canada
cDepartment of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, S7N
5B4, Canada
dSchool of Environment and Sustainability, University of Saskatchewan, 117 Science Place,
Saskatoon, SK, S7N 5C3, Canada
TitleCEW
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2015
Date
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October
5,
Toxicology Centre
Introduction
•
Lake Diefenbaker
• Large multi-purpose reservoir (225-km long) located in southern
Saskatchewan, Canada.
• Provides water for 45% of Saskatchewan residences (WSA 2012).
• Moderately eutrophic1 up-reservoir to oligo-mesotrophic downreservoir2.
•
Buffalo Pound Lake
• Provides water for 25% of Saskatchewan residences (WSA 2014).
• Naturally rich in nutrients
• Eutrophic3.
Lake Diefenbaker
Buffalo Pound Lake
1Hecker,
M., et al. 2012. J. Water Resource Prot. 4: 180-202.
et al. 2014. J. Great Lakes Res. (Submitted)
3Dodds, W. K. 2010. Freshwater Ecology: Concepts and Environmental Applications (Aquatic Ecology). ISBN: 978-0122191350.
2015
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2Dubourg
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Introduction
• Residual or “environmental” DNA in the sediment can remain preserved over
time and can possibly allow retrospective genetic monitoring of an aquatic
system5.
• eDNA can be extracted from the sediments and can be used to identify the
presence of organisms and changes in community composition.
• eDNA can provide insight regarding the emergence or presence of problematic
or harmful organisms within an aquatic system (e.g. toxin-producing
cyanobacteria).
http://media.nordicmicroalgae.org/original/Dolichospermum%20lemmermannii_1.jpg
5Turner,
C. R. et al., 2015. Biological Conservation.
2015
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Toxicology Centre
Introduction
Goal: To reconstruct historical trends of the cyanobacterial community in two
Saskatchewan reservoirs (Lake Diefenbaker and Buffalo Pound Lake).
• Study objectives:
•
Isolate DNA from sediment
and amplify the 16S rRNA
gene region to assemble
cyanobacterial
community
composition and trends .
•
Identify potentially harmful
cyanobacterial species.
•
Identify toxin producing genes
if known toxin-producers are
present.
http://media.nordicmicroalgae.org/original/Dolichospermum%20circinale_1.jpg
2015
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Sample Sites
Gardiner arm
Qu’Appelle arm
Buffalo Pound Lake
Figure 1: Map of sediment core locations from Lake Diefenbaker Gardiner arm (white),
Qu’Appelle arm (yellow) and Buffalo Pound Lake (teal) in Saskatchewan, Canada.
2015
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Toxicology Centre
Introduction
•
Lake Diefenbaker Algal Pigments:
•
•
6Tse,
Algal pigments analysis
suggested an increasing
cyanobacterial presence in
Gardiner arm6.
Myxoxanthophyll was present at
only these two locations on Lake
Diefenbaker.
et al., 2015. Journal of Great Lakes Research. Accepted September 2015.
Title or place of presentation
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Materials and Methods
•Genomic DNA (gDNA) was extracted
from sediment using EZNA Soil DNA kits.
•PCR amplification was completed using
cyanobacterial 16S rRNA primers modified
from Nübel et al., 19977 with Illumina
recommended overhangs.
7Nübel,
•
•
Sequencing was completed using a
MiSeq Desktop Sequencer.
Secondary analysis was completed using
the MiSeq Reporter, and an Illuminacurated version of the Greengenes
taxonomy database.
U., et al. 1997. Appl Environ Microbiol. 63: 3327-3332.
2015
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Results
DNA Concentration
DNA Purity
•
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DNA purity was relatively
conserved in all sediment
increments:
•
BPL ~ 1.8
•
LD: Gardiner arm ~ 1.8
•
LD: Qu’Appelle arm ~ 1.7
October 5,
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Comparisons Among Sites
Buffalo Pound Lake
Gardiner arm
2015
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Qu’Appelle arm
October 5,
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Toxicology Centre
Comparisons Among Sites and Depths
2015
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Abundance of Cyanobacteria – Buffalo
Pound Lake
2015
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Abundance of Cyanobacteria – Gardiner
arm
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Abundance of Cyanobacteria – Qu’Appelle
arm
2015
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ue
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Results Species – Buffalo Pound Lake
0
Sediment depth (cm)
5
10
15
20
25
30
0
1500 3000 0
3000 6000 0
1200 2400
0
800 1600
0
450 900
0
2000 4000
0
250 500 0
2000 4000 0 4000080000
0
800 1600
0
500010000 0
350 700
0
1500 3000
0
400 800
0 3000060000
0
300 600
0
600 1200 0
300 600
0
350 700
# of hits
•
19 different species of cyanobacteria in BPL sediments.
• 5 species with strains known to produce toxins.
1 D. circinale
2 D. lemmermannii
3 D. mendotae
4 M. novacekii
5 M. panniformis
2015
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0
ra
P.
m
ur
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D
.m
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Results Species – Lake Diefenbaker
•
8 different species of cyanobacteria in LD –
Gardiner arm sediments
• 3 species with strains known to produce
toxins.
1 D. lemmermannii
2 D. circinale
3 D. mendotae
•
6 different species of cyanobacteria in LD –
Qu’Appelle arm sediments
• 1 species with strains known to produce
toxins.
1 D. lemmermanii
Sediment depth (cm)
5
10
15
20
25
0
1500 3000
0
500 1000
0
300 600
0
600 1200 0
150 300
0
150 300
0
100 200
0
400 800
tu
m
nt
op
hy
sa
la
m
in
o
L.
ar
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an
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.p
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.l
em
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er
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.b
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ar
ss
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ni
# of hits
Sediment depth (cm)
2
4
6
8
10
0
500 1000
0
300 600
0
150 300
0
700 1400 0
90
180
0
18
36
# of hits
2015
TitleCEW
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October 5,
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Toxicology Centre
Discussion
• eDNA in sediments are fairly well preserved and can be used to track historical
changes in cyanobacterial community composition.
• Buffalo Pound Lake sediments had significantly higher abundance of cyanobacteria
DNA compared to Lake Diefenbaker sediment cores (e.g. Gardiner and Qu’Appelle
arm)
• Potentially harmful cyanobacteria were identified at all three sites.
• Cyanobacteria DNA abundance was greater in recent (top) sediments compared to
middle and bottom sediments in each sediment core.
• Useful in identifying arrival of invasive species.
• Useful in assessing changes in cyanobacterial community over time.
2015
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or place
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October 5,
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Toxicology Centre
Future Work
•
Identifying, quantifying and correlating algae toxin genes to cyanobacteria
community composition.
•
Correlating pigment data and other bio-geo-chemical datasets to cyanobacteria
community composition.
http://www.biomedcentral.com/content/figures/1471-2148-9-115-1-l.jpg
2015
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Toxicology Centre
Acknowledgements
Funding provided by:
• Global institute for Water Security (GIWS)
• Acknowledgements:
• Allison Hill
• Jon Doering
• Shawn Beitel
• Steve Wiseman
• Natural Sciences and Engineering Research
Council (NSERC) of Canada
2015
TitleCEW
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Toxicology Centre
Questions?
2015
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Date of presentation