Barry Biggs National Institute of Water & Atmospheric Research · National Institute of Water...

Barry Biggs

National Institute of Water & Atmospheric Research

For the

‘Rock-snot team’

TheDidymo Science Story

(in part)

Outline

• What is the problem?• Where does didymo do best?• Some didymo biology• Overview of BioSec NZ sponsored science

programme• Vectors – in brief• Control possibilities

Courtesy of

Southland Fish & Game

What is theproblem ?

- A worst case bloom

0

100

200

300

400

Ash

-fre

e dr

y w

eigh

t (g/

m2 )

1993

2001200220042005

199719992000

It grows in very large masses in clean waters….trophic cascade of effects

What is the problem?

Biomassguidelinefor fish2006

Lower Waiau River, Southland Didym

o arrived

Courtesy of Meridian Energy

Courtesy of

Southland Fish & Game

Waiau River trout abundance - Excelsior Creek

0

20

40

60

80

100

120

140

160

180

1996 1997 1998 1999 2000 2001 2002 2006

Tro

ut p

er k

m

Brown Trout

Rainbow TroutIncrease in f low Didymo discovery

What is the problem?

Courtesy of

Southland Fish & Game

What is theproblem?

Courtesy of

Southland Fish & Game

What is the problem?

• Hydraulic habitat preferences

0.0 0.3 0.6 0.9 1.2 1.5Water velocity at 0.6 depth (m/s)

0

100

200

300

400

500

Where does didymo do best?

Bio

volu

me

inde

x

0

100

200

300

375

Sep-2004 Oct-04 Nov-04 Dec-04 Jan-05 Feb-05 Mar-05 Apr-05s ite 79719

Flo

w r

ecor

ded

at M

LC (

m3 /

s)P

eriphyton cover index (max. 300)

Didymo mat sloughing; overgrown with black cyanobacterial mat

No bed movement Didymo dominating, but “medium mats”remnants

Mostly Didymo remnants

300

200

100

0

Jericho

�� Stable river bedsStable river beds

Where does didymo do best?

Courtesy of Meridian Energy

Some didymo biology

Prof. M. Gretz, Michigan Tech.

Some didymo biology

Prof. M. Gretz, Michigan Tech.

Some didymo biology

Overview of BioSec NZ sponsored science programme

– Monitoring • Cathy Kilroy - NIWA

– Detection• Craig Cary – Waikato Uni

– Delimitation• Maurice Duncan - NIWA

– Ecology II• Scott Larned - NIWA

– Trout • John Hayes - Cawthron

– Survival• Cathy Kilroy - NIWA

– Control• Barry Biggs - NIWA

UnderstandingDistribution

UnderstandingImpacts

Containment&

Control

Vectors – in brief

• Inter-catchment– Fishermen– Kayakers– Jet boaters– Hydro generation– Irrigation

• Intra-catchment– Fish– Birds– Vehicles– Hydro generation– Irrigation

Vectors – in brief

felt_sole

gumboot

leather_boot

neoprene0

10000

20000

30000

40000

50000Li

ve d

idym

o c e

lls p

er it

em

After 5 hr ‘drying’

felt_sole

gumboot

leather_boot

neoprene0

100

200

300

400Li

ve d

idym

o ce

lls p

er i t

em

After 36 hr ‘drying’

But, decontamination chemicals did not penetrate felt material!!

Vectors – in brief

Control possibilities

• Attacking the stalks – Stalk degradation (Prof. M. Gretz – Mich. Tech)

• Attacking the growing cells – Biocides toxic to didymo (NIWA)

-20

0

20

40

60

80

100

120

0 1 2 3 4 5 6

Time (hours)

% S

talk

Mas

s Lo

ss

Trifluoroacetic acid - RHS(1)

Penicillium enzymes (non-buffered) - RHS(1)Penicillium enzymes (non-buffered) - FD(2)Penicillium enzymes (pH 5) -FD(2)DH20 w/ Steam - FD(2)

NaOH w/ Steam - FD(2)

Penicillium enzymes (pH 5) -Fresh(3)EDTA - FD(2)

Hot Water - FD(2)

Loss of stalk material as a function of treatment

Attacking the stalks

Longer termCell toxicant10 ppmGermanium

Longer termExfoliation & degradation10 ppmEDTA

Longer termPhotosynthetic inhibitor1 ppmHydrothol

ImmediatePhotosynthetic inhibitor1000 ppmOrganic Interceptor

ImmediateCell toxicant10 ppmZinc sulphate

ImmediateMetabolic inhibitor1 ppmSimazine

ImmediateMembrane disruption20 ppmQAC

ImmediatePhotosynthetic inhibitor5 ppmDiquat

ImmediatePhotosynthetic inhibitor5 ppmCopper compound

ImmediatePhotosynthetic inhibitor5 ppmChlorine

Response timeMode of actionConcentrationBiocide

Biocide screening

Attacking the growing cells

Biocide screening

Attacking the growing cells

Monowai Experimental Facility (MEF)(at Monowai Power Station)

• Testing facility

4 Biocides @ 3 concs.

1 hr exposures

Application method

Fish added to channels as a toxicity assay

Daphnia magna used in laboratory toxicity testing

•Additional toxictyassaysMultipipettor being used during toxicity sampling

Attacking the cells -Ideal Ecotox Profile

Biocide Concentration (mg/L)

0 20 40 60 80 100 120 140

% S

urvival

0

20

40

60

80

100

120

Fish

Invertebrates

Algae

Didymo

Concentration (mg Cu/L)

0 2 4 6 8 10

Sur

vivo

rshi

p

0.0

0.2

0.4

0.6

0.8

1.0

Didymo

Invertebrates

Algae

Fish-channels Fish-Lab data

Attacking the cells –Results of Gemex TM

Where to from here?

• Devel rapid response strategy for new incursions (eg, for Tongariro) (completed)

• Short-term management– Product formulation/toxicity (started)

– Small stream field testing (trials designed, consents being applied for)

– Design short-term control/application strategies (started)

• Long-term management– Product formulation/toxicity– Application strategies– Design long-term control strategies

Acknowledgements

particularly Christina Vieglais

particularly Bill Jarvie and Stu Sutherland

particularly Peter Mulvihill and Warren Greene

Meridian Energy particularly Dave Herrick