Nutrient contributions from Dreissena spp. to Lyngbya wollei

and Cladophora glomerata Patricia Armenio

Department of Environmental Sciences and the Lake Erie Center

University of Toledo

Increased light penetration System level

Benthic Primary Production

Local level Resource importation Structural complexity

What are local-scale interactions between Dreissena and benthic algae?

Contribution to algae •  N & P

–  Ammonium and phosphate

•  CO2 –  Respiration –  Decomposition

•  Feces and pseudofeces •  Organic matter

•  Other nutrients? •  Structure

–  Hard shells increase surface area

P. Bichier

Do Dreissena contribute to benthic algal blooms?

•  Not new to Lake Erie –  Have increased

•  Decrease aesthetic value •  Health risks •  Food web structure

•  What mechanisms from Dreissena facilitate these blooms?

Lyngbya wollei •  Cyanobacterium •  Common in southeastern

US •  Recently washed up on

shores of Lake Erie •  Requires relatively low

light •  Does not attach to hard

surfaces •  Toxic?

J. Joyner

P. Bichier

Cladophora glomerata

•  Green alga •  Requires relatively high light

and hard substrate •  Blooms common from

1950s through early 1980s •  Return of blooms since

mid- 1990s not associated with P loading –  Dreissena

Higgins et al. 2008

2009 Lyngbya survey

•  140 sites total

–  113 sites had dreissenid substrate

–  77 sites had Lyngbya

–  72 sites had both •  Only 5 sites that had

Lyngbya did not have dreissenid substrate

Panek et al.

Manipulative Experiments

•  Objective: test possible reasons why Dreissena may promote the growth of benthic algae and encourage blooms – N, P – C – Other nutrients

•  10 others quantified – Structure

Experimental set-up

Live Dreissena (N=10)

Empty Dreissena (N=10) Sand (N=10)

Lyngbya Experiment

•  4 treatments •  3400 Dreissena/m2 •  230 g/m2 Lyngbya •  Low-P lake water •  12 hour photoperiod •  One week •  N=40

Pottery shards (N=10)

Fed Dreissena throughout experiment

•  Chlamydomonas reinhardtii – Phytoplankton – Labeled with stable

isotope •  13C •  15N

– Given to all tanks

Laboratory Analyses •  C and N

–  CHN analyzer •  P and other nutrients

–  ICP-OES •  Chlorophyll a

–  UV-visible spectrophotometer •  Phycocyanin

–  10-AU fluorometer •  Photosynthetic efficiency

–  DIVING-PAM fluorometer •  13C and 15N

–  Samples sent to UC Davis, CA

Positive correlation between wet weight and dry weight

y = 0.1538x + 0.1367 R 2 = 0.798

0

0.5

1

1.5

2

2.5

3

0 5 10 15 20 wet weight (g)

dry

wei

ght (

g)

p<0.0001

Lyngbya

All tanks increase in weight, but no difference among treatments

0

0.5

1

1.5

2

2.5

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Dry

wei

ght (

g)

0

10

20

30

40

50

60

70

% in

crea

se in

wet

wei

ght

Error bars = SE

Lyngbya

No difference in photosynthetic efficiency, but decreases with more dry weight

substrate type

0 0.05 0.1

0.15 0.2

0.25 0.3

0.35 0.4

0.45 0.5

live Dreissena

empty Dreissena

pottery shards

sand

Phot

osyn

thet

ic e

ffici

ency

y = -2.8267x + 2.9382 R2 = 0.3987 p<0.0001

0 0.5

1 1.5

2 2.5

3

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 photosynthetic efficiency

dry

wei

ght (

g)

Lyngbya

No difference in chlorophyll a, but higher phycocyanin in live Dreissena treatment

0 50

100 150 200 250 300 350 400 450 500

Chl

orop

hyll

a (µ

g/g)

0

1000

2000

3000

4000

5000

6000

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Phyc

ocya

nin

(µg/

g) A

C

BC AB

Lyngbya

Dreissena increased carbon content in tissue

0

50

100

150

200

250

300

350

400

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Car

bon

(mg/

g)

A

B B B

Lyngbya

Dreissena helped retain macronutrient content in tissue

0 5

10 15 20 25 30 35 40 45

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Nitr

ogen

(mg/

g)

0

1

2

3

4

5

6

Phos

phor

us (m

g/g)

A

B B B

A

B B B

Lyngbya

No P deficiency, but N deficiency in all treatments except live Dreissena

•  <143 is no P deficiency

•  >9.4 C:N is a N deficiency –  No deficiency in

live Dreissena treatment

0

2

4

6

8

10

12 C

:N ra

tio

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

0 20 40 60 80

100 120

C:P

ratio

A

B B

B

A

B B B

Kahlert 1998

Lyngbya

Dreissena helped retain nutrient content in tissue

0

0.5

1

1.5

2

2.5

3

3.5

4

Pota

ssiu

m (m

g/g)

0 0.5

1 1.5

2 2.5

3 3.5

4

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Sulfu

r (m

g/g)

A

B B

B

A

B B B

Lyngbya

However…

0

20

40

60

80

100

120

140

160

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

Cal

cium

(mg/

g) A

B B B

Lyngbya

Stable isotope: less 13C in live Dreissena treatment,

no significant difference in 15N -25

-20

-15

-10

-5

0 live

Dreissena empty

Dreissena pottery shards

sand

substrate type

δ 13

C (‰

)

A

B B B

Lyngbya

Two week preliminary experiment with Cladophora: the 13C difference goes

away and there becomes a significant difference in 15N

0

0.5

1

1.5

2

2.5

3

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

δ 15

N (‰

) A

B B

B

Summary for Lyngbya

•  Dreissena did not increase the biomass of Lyngbya

•  Increased phycocyanin •  Supplied several nutrients, prevented a

decrease in others •  Decreased Ca •  Decreased 13C •  Did not respond to substrates

Live Dreissena (N=10)

Empty Dreissena (N=10) Sand (N=10)

Cladophora Experiment

•  4 treatments •  3400 Dreissena/m2 •  160 g/m2 algae •  Low-P lake water •  One week •  12 hour photoperiod •  N=40 •  Fed Chlamydomonas

Pottery shards (N=10)

Extra data for Cladophora

•  Took algal samples after 24 hours and 48 hours – Tissue nutrient content – Stable isotope

•  Water samples from each tank at end of experiment compared to initial water – Nutrient

y = 0.1387x + 0.4254 R2 = 0.6933

0

0.5

1

1.5

2

2.5

3

0 2 4 6 8 10 12 14 16 18 wet weight (g)

dry

wei

ght (

g)

p<0.0001

Positive correlation between wet weight and dry weight

Cladophora

All tanks increase in weight, significant difference when other treatments are

grouped

0 10 20 30 40 50 60 70 80

% in

crea

se in

wet

wei

ght

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

0

2

4

6

8

10

12

wet

wei

ght (

g)

bottom biomass

B

A

Cladophora

2

0 0.2 0.4 0.6 0.8 1

1.2 1.4 1.6 1.8

live Dreissena

empty Dreissena

pottery shards

sand

substrate type

dry

wei

ght (

g)

bottom biomass

Separation in biomass, more with live Dreissena

Cladophora

Cladophora Results

•  More variability than Lyngbya

•  No difference in pigments among treatments – Chl a or b

•  No difference in photosynthetic efficiency among treatments

Photosynthetic efficiency significantly decreased at end

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

first last

day

Phot

osyn

thet

ic e

ffici

ency

Cladophora

Nutrient tissue was significantly different between days, but not treatments

live Dreissena empty Dreissena pottery shards sand

200

220

240

260

280

300

320

340

day 1 day 2 day 7

Car

bon

(mg/

g)

Cladophora

Trend of higher nutrient concentration with live Dreissena

0 0.5

1 1.5

2 2.5

3 3.5

4 4.5

Phos

phor

us (m

g/g)

live Dreissena empty Dreissena pottery shards sand

day 1 day 2 day 7 0 5

10 15 20 25 30 35 40

Nitr

ogen

(mg/

g)

Cladophora

No P deficiency, but N deficiency in all treatments

•  <143 is no P deficiency

•  >9.4 C:N is a N deficiency

Kahlert 1998

live Dreissena empty Dreissena pottery shards sand

0 20 40 60 80

100 120 140 160 180

C:P

ratio

0

2

4

6

8

10

12

14

16

day 1 day 2 day 7

C:N

ratio

Cladophora

K showed more distinct pattern at end, but was not significantly different

0

5

10

15

20

25

30

Pota

ssiu

m (m

g/g)

0

5

10

15

20

25

Sulfu

r (m

g/g)

live Dreissena empty Dreissena pottery shards sand

day 1 day 2 day 7

Cladophora

Marginally significantly difference in tissue calcium, significant decrease in

water

0

50

100

150

200

day 1 day 2 day 7

Cal

cium

(mg/

g)

0 5

10 15 20 25 30 35 40 45

Cal

cium

(mg/

l)

initial end

Cladophora

Summary for Cladophora

•  Showed a biomass increase in the live Dreissena treatment

•  No significant difference among pigments •  Showed trends of higher nutrient concentrations

in live Dreissena treatment –  C, N, P, K, S

•  Dreissena decreased Ca concentration •  **Not yet received results for 13C and 15N •  Did not respond to structure

Overall Conclusions: growth

•  Dreissena increased growth in Cladophora, but not Lyngbya –  Cladophora responded to increased nutrients

•  Dilution •  Attachment

Overall Conclusions: growth

•  Dreissena increased growth in Cladophora, but not Lyngbya –  Cladophora responded to increased nutrients

•  Dilution •  Attachment

–  Not enough time for Lyngbya –  Lyngbya growth does not always positively respond to

N and P

–  Increased PC and nutrients indicate that Lyngbya was photosynthetically healthier with Dreissena

Overall Conclusions: nutrients

•  Dreissena can retain nutrient concentrations in benthic algae – Can translate to increase biomass over time – More than just C, N, P – Higher nutrient content can mean higher

quality of algae for grazers – Decrease Ca concentration, but unlikely to

affect algae in natural system

Overall Conclusions: structure

•  Not found to be as important as nutrient contributions – No difference among empty shell, pottery

shard, or sand alone treatments – Algae were floating in the water – Cladophora bulk biomass was not able to

reattach •  More attachment with live Dreissena

Implications •  Dreissena increased algal biomass of one species and

contributed several important nutrients to benthic algae –  Supports nearshore shunt hypothesis

Implications •  Dreissena increased algal biomass of one species and

contributed several important nutrients to benthic algae •  Nutrient reduction policies help control algal blooms, but

Dreissena aggregate N and P which benefits benthic algae –  May promote blooms despite reduced loading –  Target nutrient levels may have to be lower than previously

believed –  Nutrient reductions may be ineffective

•  Dreissena help benthic algae acquire C •  Benthic algae have a low affinity for nutrients in water column

Implications •  Dreissena increased algal biomass of one

species and contributed several important nutrients to benthic algae

•  Nutrient reduction policies help control algal blooms, but Dreissena aggregate N and P which benefits benthic algae

•  Algae can store nutrients –  Helpful when nutrient availability is low

•  Create longer presence of algae

Acknowledgements •  Advisor: Dr. Christine Mayer •  Committee: Dr. Scott Heckathorn, Dr. Thomas Bridgeman,

Dr. Rex Lowe •  Department of Environmental Sciences and the Lake Erie

Center •  Dr. Jonathan Frantz & USDA ARS team at UT •  Plant Science Research Center •  Lab/Field/Other Help

–  Mike Bur and Patrick Kocovsky, USGS –  Kristen DeVanna, Justin Chaffin, Sasmita Mishra, Dominic

Armenio, Sarah Panek, Shellie Phillips, Rachel Kuhanek, Nate Manning, Peter Bichier, Mike Kuebbeler, Todd Crail, Chris Bronish, Sam Guffey, Blake Quinton, Steve Timmons, Jeremy Pritt, Dale Lorenzen III

•  Funding sources –  Lake Erie Protection Fund, SG 384-10 –  EPA Lake Erie Algal Source Tracking