1 / 22

Projected changes to the tropical Pacific Ocean

Projected changes to the tropical Pacific Ocean. Based on Chapters 3 & 4. Outline. Projected temperatures and currents: surface and vertical structure Implications for oceanic nutrients Acidification Food web for tuna Influence of temperature on tuna. Sea surface temperature.

reia
Download Presentation

Projected changes to the tropical Pacific Ocean

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Projected changes to the tropical Pacific Ocean

  2. Based on Chapters 3 & 4

  3. Outline • Projected temperatures and currents: surface and vertical structure • Implications for oceanic nutrients • Acidification • Food web for tuna • Influence of temperature on tuna

  4. Sea surface temperature Change in SST °C (2000-2100) • 2000: 27.4°C • 2035: 28.1°C (+0.7°C) • 2100: 29.9°C (+2.5°C) Ocean is heat sink!

  5. Vertical structure and stratification } Warm, mixed-layer } Thermocline depth } Cold, deepocean

  6. Vertical structure and stratification } } }

  7. Vertical structure and stratification • Most warmingoccurs at surface • Leads to increase in stratification

  8. Projected changes in vertical currents Less downwelling Less downwelling Less UPWELLING Less downwelling

  9. Implications for nutrients Warm, mixed-layer • Thermocline acts as a barrier • Limits the supply of nutrients Cold, deepocean Lownutrient High nutrient

  10. Implications for nutrients Warm, mixed-layer Cold, deepocean Lownutrient Increased stratification makes it harder to bring nutrients upwards High nutrient

  11. Why is this important? Nutrients support the food web for tuna

  12. Image: Marc Taquet, FADIO, IRD/IFREMER

  13. Projected changes in major currents

  14. Eddies

  15. Nutrient supply by eddies • Eddies temporarily lift the nutrient-rich waters • Eddy activity is related to current strengths

  16. Eddies and nutrients

  17. Convergence zone

  18. Similarities with ENSO • Skipjack tuna catch Source: Lehodey et al. (1997)

  19. Ocean acidification

  20. Projected acidification • Saturation >4 healthy conditions • Saturation falls below 3.3 causing problems for some corals • Saturation decreases to 2.4

  21. Sea level rise

  22. Summary • Increases in sea surface temperature • Stronger stratification • Nutrient supply reduced due to increase in stratification, with effects on tuna food web • Slowdown of equatorial currents and upwelling • Aragonite drops below critical levels • Sea level rise, > 1 m cannot be ruled out

More Related