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Effects of low salinity and sediments
- n sea urchin larvae
Andrea Glockner-Fagetti
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on sea urchin larvae Andrea Glockner-Fagetti 1 What we do at - - PowerPoint PPT Presentation
on sea urchin larvae Andrea Glockner-Fagetti 1 What we do at - - PowerPoint PPT Presentation
Effects of low salinity and sediments on sea urchin larvae Andrea Glockner-Fagetti 1 What we do at Victoria University Coastal Ecology Lab VUCEL supports SBS research programmes in coastal ecology that are conducted in the Wellington
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Annual Open Day
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@VUCEL
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We study…
- The natural history and
biology of organisms
- Interactions between
- rganisms
- How organisms are
affected by their environment
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Current students
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PhD in progress…
- Ecology and
reproduction of sea urchin (Evechinus chloroticus)
- Species of ecological and
economical importance
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Circulation patterns
Wellington Harbour South coast Wellington City
Exposed to runoff
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Study site
South Coast Harbour
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Research questions
South Coast Harbour Are the differences in density due to different reproductive patterns? Do natural stressors affect larval development? How? If so… what is affecting reproductive patterns?
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Life cycle of sea urchins
Water column Benthos Spawning Fertilisation Larval development Metamorphosis Settlement
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Recruitment
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Aims
- 1. To analyze the effects of low salinity and
suspended sediments on larval development of kina
- 2. To estimate the carry-over effects on
settlement success
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Larval cultures
Methods: Aim 1 Spawning Fertilisation Larval cultures
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Methods: Aim 1 Spawning
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Fertilisation
15 min later… 24 h later…
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Methods: Aim 1
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Methods: Aim 1
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Larval cultures
3 days later…
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Low High No (Control) Low salinities 28 32 36 Low High No Suspended sediments
Larval treatments
Methods: Aim 1
Measurements: Arm length Survival Proportion of normal larvae
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Statistical analysis: Multi-factorial ANOVA Fully factorial design 3x3 Replicates x3
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Settlement success
Carry-over effects on settlement
Methods: Aim 2
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Results
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Salinity 28 Salinity 32 Salinity 36 (Control) 3 7 14 21 Day 0.0 0.1 0.2 0.3 0.4 0.5 0.6 PO arm length (mm)
Larval growth
Salinity effect
PO
Growth delayed by salinity 28 Sediment effect
Results: Aim 1
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Low High No (Control) 3 7 14 21 Day 0.0 0.1 0.2 0.3 0.4 0.5 0.6 PO arm length (mm)
Larval growth
Salinity effect
PO
Sediment effect
Results: Aim 1
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0.2 0.4 0.6 0.8 1 Day 3 Day 7 Day 14 Day 21 Proportion of normal larvae 28 32 36
100 µm
Normal Abnormal
Proportion of normal larvae at different salinity treatments
Results: Aim 1
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Results Aim 2
Larvae exposed to salinity 28 had lowest settlement success
Settlement success
Results: Aim 2
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10 20 30 40 Low High Control Settlement success (%) Sediment treatment 28 32 36
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Survival of settlers
Results: Aim 2
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5 10 15 20 25 1 2 3 4 Number of settlers Week 28 32 36 Normal Abnormal
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Summary
- Low salinities had a negative effect on larval
growth and caused strong abnormalities
- Combination of low salinity and high sediments
caused lowest larval survival rates
- Settlement success was less than 10% for larvae
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- Carry-over effects on survival and growth of
settlers
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Conclusion
Even a short exposure to stressors during larval development has strong consequences in settlement, which could compromise recruitment to the adult population Further studies are needed to investigate long-term survival of settlers
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Thank you for your attention!
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