particles (TEP) under ocean

sixcageyMechanics

Feb 22, 2014 (3 years and 3 months ago)

69 views

Transparent exopolymer
particles (TEP) under ocean
acidification conditions

Presented by Daneil Newcomb at Friday Harbor Labs for the Ocean
Acidification Apprenticeship

What is TEP?


A carbohydrate rich polysaccharide form of organic matter
produced by phytoplankton and some bacteria


Most likely produced as a response to cell stress (too little or
too much of a resource), not seen in actively growing cells


Increased TEP production is correlated with the maintenance
and senescence phases of phytoplankton growth


In previous ocean acidification studies:


Bulk TEP has been correlated to chlorophyll
-
a, bacterial production,
dissolved organic matter, and particulate organic matter


These correlations appear to be dependent on the presence of a phytoplankton
bloom.


A possible mechanism to increase export of carbon from
surface waters to depth


(
Wurl

et al. 2011)

Phytoplankton exude
polysaccharides

(
Wurl

et al. 2011)

Phytoplankton exude
polysaccharides

TEP is formed through
aggregation

(
Wurl

et al. 2011)

TEP is formed through
aggregation

Phytoplankton exude
polysaccharides

Aggregates
are removed
from system
via export

marine snow

(
Wurl

et al. 2011)

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Factors affecting TEP production and
cycling


Abiotic


Temperature


Turbulence


pH


Nutrients


Sedimentation



Biotic


Phytoplankton and
bacterial production


Bacterial
remineralization


Viral lysis


Grazing by zoo
-

and
microzooplankton

Experimental Objectives


Determine how chosen factors affect TEP
production within the mesocosm experiment


To examine correlations between bulk TEP
production and phytoplankton, bacteria, and
microzooplankton
.


To determine any significant difference in TEP
production between in situ water conditions and
FHL and the acidified ocean of the future.

Materials and Methods


Nine mesocosms, three
treatments


Duplicate samples taken
with an integrated
sampler


Samples filtered within
two hours of collection*


* Except made for fossil hunting


Materials and Methods


Analyzing TEP


Filters are stained with
Alcian

Blue, soaked in
80% sulfuric acid, then
analyzed using the
colorimetric method.


Absorbance is related to
weights using a
calibration curve

y = 0.0008x + 0.0575

R² = 0.6826

y = 0.0007x + 0.0201

R² = 0.5747

y = 0.0011x + 0.0253

R² = 0.921

0
0.05
0.1
0.15
0.2
0.25
0
50
100
150
200
Absorption (E787
-

C787)

Gum Xanthan (
m
g)

TEP Mesocosm Time Series

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)

HIGH

CONTROL

DRIFT

DOCK

TEP Mesocosm Time Series

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)

TEP Mesocosm Time Series

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)

Drift
-
High

0.848


p

< 0.001

Control
-
High

0.030

p = 0.902

Drift
-
Control

0.879

p = 0.001

TEP Mesocosm Time Series

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)

Why are the high and control
different from the drift but not
each other?

What makes the drift different?

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP (
m
g Gum
Xanthan

L
-
1
)

Time (Days)


How are the biotic
factors, such as
phytoplankton and
bacteria, responding to
the treatments?


How do the abiotic factor
differ between
treatments?


Which of these abiotic
factors effect the
physiological response
of these organisms?


Biotic Factor:
Phytoplankton

0
5
10
15
20
25
30
35
40
T0
T2
T4
T6
T8
T10
T12
T14
T16
T18
T20
Median Chlorophyll
(
m
g L
-
1
)

Time
(Days
)


Both Chlorophyll a and TEP
show the control ending above
the high, and increase over
time.


For both the drift treatment is
significantly lower than the
high treatment.


Suggest phytoplankton are the
main producers of TEP in the
system.


0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g
Gum
Xanthan

L
-
1)

Time (Days)

r

Control

0.837

High

0.851

Drift

0.794

P < 0.001

Biotic Factor:
Bacteria


The control and high
treatments are
significantly higher than
the drift treatment for
both Bacterial
Abundance and TEP.


0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g
Gum
Xanthan

L
-
1)

Time (Days)

r

Control

0.882

High

0.754

Drift

0.388

P < 0.03

But why is the drift significantly lower?


All treatments experienced the same
temperature and turbulence conditions


Initial nutrients were highly similar in all
treatments


The only factor which changed between
treatments was the pCO2


Drift was allowed to change whereas High and
Control concentrations were maintained

But why is the drift significantly lower?

DRIFT

But why is the drift significantly lower?

But why is the drift significantly lower?

But why is the drift significantly lower?

Photosynthesis: 106CO
2

+ 16NO
3

+ PO
4



ORGANIC MATTER + 138O
2

But why is the drift significantly lower?

HIGH OR
CONTROL

But why is the drift significantly lower?

But why is the drift significantly lower?

But why is the drift significantly lower?

Photosynthesis: 106CO
2

+ 16NO
3

+ PO
4



ORGANIC MATTER + 138O
2

But why is the drift significantly lower?

Photosynthesis: 106CO
2

+ 16NO
3

+ PO
4



ORGANIC MATTER + 138O
2

But why is the drift significantly lower?

Conclusions


TEP production is affected by repetitive
enrichment of waters with CO
2



The ways different factors influence TEP
concentrations are complex. Further studies
should be completed to ensure a better
understand of how TEP functions under ocean
acidification conditions.

Acknowledgements


OA apprentices, technicians, and advisors!


Jim Murray, Evelyn
Lessard
, Mike Foy, Amanda Fay, Barbara Paul, Kelsey, Amy,
Natsuko
,
Jennifer,
Kiely
, Phil, Kelly, Andrew.


Friday Harbor Labs


Project Funding:


Educational Foundation of America and the National Science Fund for funding the project


Alice M. Barger and Andrea Reister for funding my education the past two years


Mary Gates Research Endowment Fund


Steve Emerson and Kathy
Krogsland

for use of their lab equipment
at the UW



My family, partner, friends, and current roommate, Collin, for all of
the great support


Works Cited


TEP Mesocosm Time Series

0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
800.00
900.00
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
TEP (
m
g Gum
Xanthan

L
-
1
)

Time (Days)

Figure 1. Transparent exopolymer particle time series based on median values. Error
bars are the median standard deviation Green data represent control mesocosms, red
high mesocosms, blue drift mesocosms, and black the dock. Statistically significant
differences were found between the drift and high treatment (0.848, p=0.001) and the
drift and control treatment (0.879, p=0.000).

Why did TEP peak and then drop in
all treatments?

What caused the
sudden decreased
in TEP?

0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
800.00
900.00
0
2
4
6
8
10
12
14
16
18
20
TEP (
m
g Gum
Xanthan

L
-
1
)


Unlikely due to
sampling error, present
in all bags


Both Temperature and
pCO2 decrease in days
prior to TEP decrease


Source says
temperature affects
TEP production?

0
200
400
600
800
1000
1200
1400
1600
0
2
4
6
8
10
12
14
16
18
20
pCO2

8.00
8.10
8.20
8.30
8.40
8.50
8.60
8.70
0
2
4
6
8
10
12
14
16
18
20
Temperature (
°
C)

Time (days)

Biotic Factor: Phytoplankton


TEP production often
associated with
maintenance and
senescence phase of
phytoplankton


Population of
Thalassiosira

has
growth rates constant
and close to zero,
suggesting this is a
source of TEP

-20
-10
0
10
20
30
40
50
60
70
80
0
2
4
6
8
10
12
14
16
18
20
Growth
Rate

( cells days^
-
1)

Time (days)

Experimental Results


Were there any significant differences in TEP
production between current water conditions
and the predicted future conditions?




What biotic factors was TEP correlated to
within our mesocosm?




Why was the drift significantly different from
the high and the control, but the high and
control were not different from each other?




Why were initial TEP concentrations about
zero?


There was no significant difference between
TEP production in the control treatment and
the high treatment, but the drift treatment
was different from the control and high.



TEP is significantly correlated to Chlorophyll
a, Biogenic Silica, and Bacteria Abundance.





higher production is most likely associated
with the
repeatative

enrichment of CO2 to
the control and high treatments but not the
drift





Turbulence during filling of the mesocosms

TEP Mesocosm Time Series

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)

Why doesn’t TEP start at zero?

Why were initial concentrations of
TEP above zero?

0
100
200
300
400
500
600
700
800
900
0
2
4
6
8
10
12
14
16
18
20
Median TEP
(
m
g Gum
Xanthan

L
-
1
)

Time (Days)


Previous mesocosm
studies show increased
turbulence results in
increased TEP
formation in water


Highly turbulent
conditions persistent
during mesocosm
filling

Biotic Factor: Phytoplankton

y = 23.279x + 131.3

r

= 0.794

y = 22.623x + 152.07

r =

0.851

y = 19.285x + 167.47

r

= 0.873

0
100
200
300
400
500
600
700
800
0
5
10
15
20
25
Median TEP
(mg Gum
Xanthan

L
-
1
)

Median Chlorophyll
a
(
m
g L
-
1
)

y = 47.171x + 7.0361

r

= 0.687

y = 43.341x + 11.007

r

= 0.794

y = 61.23x
-

13.772

r
= 0.871

0
100
200
300
400
500
600
700
800
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Median TEP
(
m
g Gum
Xanthan


L
-
1
)

Median Biogenic
Silica (
m
mol

L
-
1
)

p < 0.01

p < 0.01

Biotic Factor: Bacteria


Two possible reasons
for this correlation:


Bacteria are producing
TEP


Currently no method for
discerning from a bulk
value whether TEP is
phytoplankton or bacteria
derived


Bacteria are
remineralizing

TEP


Further information
necessary

y = 0.0002x
-

28.908

r

= 0.388

y = 0.0003x
-

55.471

r

= 0.754

y = 0.0002x + 2.5189

r =

0.882

0
100
200
300
400
500
600
700
800
0.00E+00
1.00E+06
2.00E+06
3.00E+06
4.00E+06
Median TEP
(mg Gum
Xanthan

L
-
1
)

Median Bacterial
Abundance (cell mL
-
1
)

p < 0.05