algae/proposals/lake_fenton.htm

April 18, 2001

Proposal title:

Proposal subject: lake chemistry, Fenton reaction potential, mixing,

target agency:

Objective: to demonstrate that the chemistry of iron in the water, and in particular the potential to form hydroxyl radical species, is a major constraint to growth of algae

Introduction

PvsE - photoinhibition effect

Ecritical as another way to look at this

imbalance in energy in different lights - phase 1 and 2

Production of H2O2 and sideproducts, in particular OH<dot>

Fenton reaction in media (EDTA chemistry)

Ecological context -

relate to CSR - see Pahl-Wostl

 

hypothesis: Cells produce H2O2, H2O2 plus FeChelator compexes produces OH<dot>, OH<dot> causes cell damage and inhibition

measurements:

1. Fenton reaction in water samples

a. filtered samples

b. add H2O2

c. DFB or other agent that blocks Fenton rxn

 

 

2. algal H2O2 production in vitro simulations of lake mixing regimes

a. example light trajectory calculated from Lake number, attenuation,

b. example light trajectories measured with Lagrangian floaters**

needs development

recording light data-aquisition in neutral density bags with timer

check Hobo

c. Hansatech O2 electrode measurments of O2 production vs. light and H2O2 production

d. scopoletin assay on collected samples (fixed sample method)

 

 

3. simulated effect of OH<dot> radical on algae

a. photoinhibition studies (preliminary data)

b. Ecritical

 

 

4. Siderophore production

CAS-HDTMA assay in lake water

Fe binding - OH<dot> production

 

Field Work

choice of lakes

iron present - high humics, such as Klamath lake

high altitude - high irradiance - Bend area lakes

 

Possible significance

constraint for algal growth in natural waters

fast growing cells/fast photosynthesizing cells may cause themselves more damage

related to medium chemistry

explains some aspects of Fe toxicity in growth media

possible value for siderophore production