Transcript Effects of Hypoxia on Survival and Growth of Barnacle Larvae Off the

Effects of Hypoxia on Survival and
Growth of Barnacle Larvae Off the
Oregon Coast
Amanda Amstutz
Department of Zoology
Dr. Bruce Menge
Dafne Eerkes-Medrano
Department of Zoology
HYPOXIA:
Dissolved oxygen concentrations of less than 1.4 ml /L
• Hypoxia can cause mass die offs of marine life in
areas known as DEAD ZONES
Hypoxia off the Oregon Coast
• Hypoxia in shallow waters
(50m or less) was first documented
in the summer of 2002 and has
occurred every summer from 2002-2007
Hypoxia off the Oregon Coast
A healthy rockfish reef before 2006 anoxia (left)
and after 2006 anoxia (right).
Barnacles!
 Barnacles are found on hard
substrata in coastal regions
 They are filter feeders
 Barnacles have a total of eight life
stages
 Seven of these life stages are
open-ocean larval forms
www.microscopy-uk.org.uk/mag/imgjan99/naup.jpg
Barnacles are important as:
Ecological engineers
Prey
Photos courtesy Dr. Mark Hixon
Because barnacles are ecologically important species, fluctuations in barnacle
populations effect entire ecosystems.
Rear barnacle larvae in the laboratory
Research Goals:
Expose larvae to hypoxia
1. Determine mortality of larvae
Measure
at increasingly severe
levelssurvival
of hypoxia for a
given exposure period
Monitor
growth
and
development
2. Determine if exposure to hypoxic
conditions effects growth of larvae
Predictions:
 Due to the historical lack of hypoxia close to shore, barnacle
larvae are predicted to experience high mortality when
exposed to hypoxia
 Larvae are predicted to experience increased mortality with
increasing severity of hypoxia and duration of exposure
 Larvae are predicted to have slower growth rates when they
have been exposed to hypoxia
Preliminary Results
experiment 1
1.2
microxia
normoxia
proportion mortality
1.0
0.8
0.6
0.4
0.2
0.0
0
1
2
3
4
5
6
7
days after 24 hr exposure
Cumulative mortality of Balanus glandula mixed stage larvae through a six day
period after exposure to microxia (0.5 mg/l dissolved oxygen) or normoxia (5 mg/L
dissolved oxygen) for 24 hours. (Means ±SD; normoxia n=3; microxia n=3 )
What’s Next
 Ensure errors in system have been corrected
 Perform 48 and 72 hour trials
 Monitor development and growth
Acknowledgements
 Howard Hughes Medical Institute
 OSU University Honors College
 Dr. Kevin Ahern
 Dr. Bruce Menge and Dafne Eerkes-Medrano
 Hatfield Marine Science Center
 Dr. Chris Langdon