APMS 2005, San Antonio, Texas Production and growth rates of Egeria densa in the Sacramento-San Joaquin Delta, California Toni G. Pennington & Mark D.

APMS 2005, San Antonio, Texas

Production and growth rates of Production and growth rates of Egeria densaEgeria densa in in the Sacramento-San Joaquin Delta, Californiathe Sacramento-San Joaquin Delta, California

Toni G. PenningtonToni G. Pennington&&

Mark D. SytsmaMark D. SytsmaCenter for Lakes & ReservoirsCenter for Lakes & Reservoirs

Portland State UniversityPortland State UniversityPortland, OregonPortland, Oregon


Models of growth & Models of growth & productionproduction

• Important to know conditions that favor/limit growth of Important to know conditions that favor/limit growth of nuisance aquatic plants under variable climates nuisance aquatic plants under variable climates Light availability, temperature, nutrients, water velocity, Light availability, temperature, nutrients, water velocity,

alkalinityalkalinity• Better inform management decisionsBetter inform management decisions

Herbicide application time, herbivore requirementsHerbicide application time, herbivore requirements• To predict effects of changing plant assemblages on water To predict effects of changing plant assemblages on water

quality and vice versaquality and vice versa Restoration, changes in turbidityRestoration, changes in turbidity


Egeria densaEgeria densa (Brazilian elodea)(Brazilian elodea)

• Submersed macrophyte Submersed macrophyte • DioeciousDioecious• Reproduces by fragmentationReproduces by fragmentation• Introduced through aquarium tradeIntroduced through aquarium trade• Widely naturalized (Japan, New Zealand, Australia, Widely naturalized (Japan, New Zealand, Australia,

Denmark, Germany, France, Chile) Denmark, Germany, France, Chile) • Impedes recreation & navigation Impedes recreation & navigation • Alters pH and temperatureAlters pH and temperature• Controlled by herbicides and mechanical meansControlled by herbicides and mechanical means


E. densaE. densa distribution in US distribution in USw

ww

. pl

ant

s.us

da.g

ov


www. ucce.ucdavis.edu


PurposePurpose

• To describe seasonal phenological To describe seasonal phenological responses of responses of EgeriaEgeria growing in growing in Western waterways to improve Western waterways to improve management efforts management efforts

• Accomplished by determining Accomplished by determining seasonal changes in: seasonal changes in: – nitrogen allocation nitrogen allocation – rates of photosynthesis & growth rates of photosynthesis & growth


HypothesesHypotheses

• Egeria Egeria exhibits changes in nitrogen allocation between plant exhibits changes in nitrogen allocation between plant parts and seasons parts and seasons

• There are seasonal differences in maximum photosynthetic There are seasonal differences in maximum photosynthetic rate, light saturation, and growth rates of rate, light saturation, and growth rates of EgeriaEgeria


Methods & results overviewMethods & results overview

• Study siteStudy site• Seasonal nitrogen allocationSeasonal nitrogen allocation• Photosynthetic responsePhotosynthetic response

– Maximum photosynthetic Maximum photosynthetic rate (Pmax)rate (Pmax)

– Photosynthetic efficiencyPhotosynthetic efficiency– Light saturation levelsLight saturation levels

• Growth rateGrowth rate


Methods - Methods - study sitestudy site

• Sacramento-San Joaquin Delta, Sacramento-San Joaquin Delta, CA (Disappointment Slough)CA (Disappointment Slough)– Upper San Francisco BayUpper San Francisco Bay– 700 mi. of channels and 700 mi. of channels and

sloughssloughs– California Bay-Delta California Bay-Delta

Restoration ProjectRestoration Project

Ray Sterner, John H

opkins Univ.


Methods – nitrogen allocationMethods – nitrogen allocation

• Plants collected monthly Dec 2003 to June 2005Plants collected monthly Dec 2003 to June 2005• Separated into: Separated into:

– Tips (upper 3 cm)Tips (upper 3 cm)– Lower stems (1Lower stems (1stst 15 cm from root crown) 15 cm from root crown)– Root crownsRoot crowns– RootsRoots

• Dried at 70Dried at 70ººC and groundC and ground• Analyzed on CHN elemental analyzerAnalyzed on CHN elemental analyzer


• In tips: highest in winter ( 5.5%) and lowest in late summer (3.5%)In tips: highest in winter ( 5.5%) and lowest in late summer (3.5%)• Lower stems: 2.7% Lower stems: 2.7% • Root crowns: 3.6% Root crowns: 3.6% • Roots: 2.7%Roots: 2.7%

Results - nitrogen allocation

1

2

3

4

5

6

O-0

3

N-0

3

D-0

3

J-04

F-0

4

M-0

4

A-0

4

M-0

4

J-04

J-04

A-0

4

S-0

4

O-0

4

N-0

4

D-0

4

J-05

F-0

5

M-0

5

A-0

5

M-0

5

J-05

J-05

% N

Tips

1

2

3

4

5

6

O-0

3

N-0

3

D-0

3

J-04

F-0

4

M-0

4

A-0

4

M-0

4

J-04

J-04

A-0

4

S-0

4

O-0

4

N-0

4

D-0

4

J-05

F-0

5

M-0

5

A-0

5

M-0

5

J-05

J-05

% N

Tips Lower stems

1

2

3

4

5

6

O-0

3

N-0

3

D-0

3

J-04

F-0

4

M-0

4

A-0

4

M-0

4

J-04

J-04

A-0

4

S-0

4

O-0

4

N-0

4

D-0

4

J-05

F-0

5

M-0

5

A-0

5

M-0

5

J-05

J-05

% N

Tips Lower stems Root crowns

1

2

3

4

5

6

O-0

3

N-0

3

D-0

3

J-04

F-0

4

M-0

4

A-0

4

M-0

4

J-04

J-04

A-0

4

S-0

4

O-0

4

N-0

4

D-0

4

J-05

F-0

5

M-0

5

A-0

5

M-0

5

J-05

J-05

% N

Tips Lower stems Root crowns Roots


Methods – production rateMethods – production rate

• Monthly from Dec 2003 to June 2005 bet. 10 am and 2 pmMonthly from Dec 2003 to June 2005 bet. 10 am and 2 pm• Incubated 15 cm tips in 300 ml BOD bottles in shipboard Incubated 15 cm tips in 300 ml BOD bottles in shipboard

circulating water bathcirculating water bath• Five light levels: 0 to 100% of surface irradianceFive light levels: 0 to 100% of surface irradiance• Measured DO, pH, and DIC to model Measured DO, pH, and DIC to model Pmax, photosynthetic Pmax, photosynthetic

efficiency and light saturationefficiency and light saturation


Photosynthesis versus Irradiance (P vs I) curvesPhotosynthesis versus Irradiance (P vs I) curvesMichaelis – MentenMichaelis – Menten

P = P = (Pmax * I)(Pmax * I)

Ik + IIk + I

Pmax

Photosynthetic efficiency

Light saturation (I sat)


• Same PmaxSame Pmax• Different saturationDifferent saturation


Results – production ratesResults – production rates

• For some months, maximum production rates were For some months, maximum production rates were not achievednot achieved

• Why? Low ambient lightWhy? Low ambient light


Results – Results – Photosynthetic Photosynthetic

efficiencyefficiency

(-) surface irradiance (+) %N in upper stems(-) surface irradiance (+) %N in upper stems

y = -1E-05x + 0.0339

r2 = 0.61p = 0.0001

0

0.01

0.02

0.03

0.04

0.05

0 1000 2000 3000Surface irradiance

Ph

oto

sy

nth

eti

c e

ffic

ien

cy

y = 0.0126x - 0.0282

r2 = 0.32p = 0.018

0

0.01

0.02

0.03

0.04

0.05

0.06

2.5 3.5 4.5%N Upper stems

Ph

oto

sy

nth

eti

c e

ffic

ien

cy


Results – monthly PmaxResults – monthly Pmax

• Where maximum photosynthetic rate was observed, model Where maximum photosynthetic rate was observed, model and observed mean Pmax in close agreementand observed mean Pmax in close agreement

• Positive but weak relationship between Pmax and Positive but weak relationship between Pmax and temperature (p = 0.06)temperature (p = 0.06)

0

2

4

6

8

10

12

D-0

3

J-04

F-0

4

M-0

4

A-0

4

M-0

4

J-04

J-04

A-0

4

S-0

4

O-0

4

N-0

4

D-0

4

J-05

F-0

5

M-0

5

A-0

5

M-0

5

J-05

Pm

ax

(m

g O

2/m

g D

W/h

)

Observed Mean Pmax

Modelled Pmaxy = 0.1526x + 2.2253

r2 = 0.25p = 0.06

0

2

4

6

8

10

8 12 16 20 24Temperature (C)

Pm

ax


Results - light saturationResults - light saturation

• Light saturation for Light saturation for EgeriaEgeria ranged from 130 to 690 ranged from 130 to 690 µµE mE m-2-2 s s-1-1 and and averaged 400 averaged 400 µµE mE m-2-2 s s-1-1

• Low saturation levels positively associated with increased N contentLow saturation levels positively associated with increased N content

SpeciesSpecies Collection site Collection site (Temp C)(Temp C)

Saturation Saturation ((µµE mE m-2-2 s s-1-1))

ReferenceReference

V. americanaV. americana WI lake (25)WI lake (25) 140140 Titus & Adams 1979Titus & Adams 1979

E. densaE. densa CA Delta (8-25)CA Delta (8-25) 400400 Present studyPresent study

M. spicatumM. spicatum FL lakes (30)FL lakes (30) 600600 Van et al. 1976Van et al. 1976

H. verticillataH. verticillata FL lakes (30)FL lakes (30) 600600 Van et al. 1976Van et al. 1976

C. demersumC. demersum FL lakes (30)FL lakes (30) 700700 Van et al. 1976Van et al. 1976


Methods – seasonal Methods – seasonal growth rategrowth rate

• ~20 plants tagged on six occasions ~20 plants tagged on six occasions • Measured for tip, stem and Measured for tip, stem and

branch/bud growthbranch/bud growth• Potted in Delta sediment and allowed Potted in Delta sediment and allowed

to grow ~ three weeks in situto grow ~ three weeks in situ


Results – growth Results – growth ratesrates

• Tips: 0.2 to 0.7 cm Tips: 0.2 to 0.7 cm .. d d-1-1

• Stems: 0.02 to 0.3 cm Stems: 0.02 to 0.3 cm .. d d-1-1

• Branch/bud: 0.03 to 0.8 cm Branch/bud: 0.03 to 0.8 cm .. d d-1-1

• Cumulative: 1 cm dCumulative: 1 cm d-1-1 April 2005 April 2005

AA

B

AAA

0

0.2

0.4

0.6

0.8

1

Nov-03 Dec-03 Apr-04 Aug-04 Nov-04 Apr-05

Gro

wth

(c

m/d

)

Tip

A AA

B

AA

A

B

AB A

B

0

0.2

0.4

0.6

0.8

1


Gro

wth

(c

m/d

)

Tip Stem

A AA

B

AA

A

B

AB A

B

A

A

A

0

0.2

0.4

0.6

0.8

1


Gro

wth

(c

m/d

)

Tip Stem Branch/bud


ConclusionsConclusions

• Maximum nitrogen content observed in tips during the winter Maximum nitrogen content observed in tips during the winter and least in roots compared to all plant partsand least in roots compared to all plant parts

• Nitrogen content positively associated with photosynthetic Nitrogen content positively associated with photosynthetic efficiency and negatively associated with light saturation efficiency and negatively associated with light saturation

– i.e. more nitrogen = more efficient with less lighti.e. more nitrogen = more efficient with less light

• Maximum photosynthetic rates occurred during the summer, Maximum photosynthetic rates occurred during the summer, however that relationship to temperature was weakhowever that relationship to temperature was weak

• Maximum growth rate occurred during in April and growth Maximum growth rate occurred during in April and growth continued through the wintercontinued through the winter


SummarySummary

• EgeriaEgeria under ideal temperature under ideal temperature conditions in the Deltaconditions in the Delta

• No “winter-type” growth form as No “winter-type” growth form as observed in S. Carolina and Japanobserved in S. Carolina and Japan

• Rapid spring growth suggests early Rapid spring growth suggests early season systemic herbicide application season systemic herbicide application

• Capable of adapting to low lightCapable of adapting to low light

Reduced photosynthetic efficiency with increased lightReduced photosynthetic efficiency with increased light

Low light saturation levels during the winterLow light saturation levels during the winter


AcknowledgementsAcknowledgements

California Bay-Delta AuthorityCalifornia Bay-Delta Authority

USDA-APHISUSDA-APHIS

Perry Lake ManagementPerry Lake Management

Aquatic Ecosystem Aquatic Ecosystem Restoration FoundationRestoration Foundation

Staff & Students at the Center Staff & Students at the Center for Lakes & Reservoirsfor Lakes & Reservoirs

San Marcos River, Texas 1998

APMS 2005, San Antonio, Texas Production and growth rates of Egeria densa in the Sacramento-San Joaquin Delta, California Toni G. Pennington & Mark D.

Documents

san antonio

light saturation slide

texas production

growth rates of egeria

turbidity slide

oregon slide

texas photosynthesis

texas www