tracking coastal hypoxia: learning from the evidence for remediation (iwc6 presentation)

Tracking Coastal Hypoxia:Tracking Coastal Hypoxia:Learning from the Evidence Learning from the Evidence

for Remediationfor Remediation

Tracking Coastal Hypoxia:Tracking Coastal Hypoxia:Learning from the Evidence Learning from the Evidence

for Remediationfor RemediationRobert J Díaz

diaz@vims.edu

http://www.vims.edu/deadzone/

Robert J Díaz

diaz@vims.edu

http://www.vims.edu/deadzone/

Why is Hypoxia a problem?Why is Hypoxia a problem?

Seriousness of low Dissolved Oxygen is best expressed by motto of American Lung Association:

““When You Can’t Breathe, When You Can’t Breathe, Nothing Else Matters.”Nothing Else Matters.”

Spread of HypoxiaSpread of HypoxiaIn the 1960s the number of systems with reports of

hypoxia-related problems started to increase.

Diaz & Rosenberg 2008Updated by Diaz et al. 2010

www.wri.org/project/eutrophication

Spread of HypoxiaSpread of HypoxiaBy the 1980s there was an explosive increase in the number of

hypoxic systems.

Diaz & Rosenberg 2008Updated by Diaz et al. 2010

www.wri.org/project/eutrophication

Spread of HypoxiaSpread of HypoxiaBy the 1990s and 2000s most estuarine and marine systems in

close proximity to population centers had reports of hypoxia/anoxia.

Diaz & Rosenberg 2008Updated by Diaz et al. 2010

www.wri.org/project/eutrophication

Oxygen Minimum Zones (<0.5 ml/l) Touch 1,148,000 kmOxygen Minimum Zones (<0.5 ml/l) Touch 1,148,000 km22 of Seafloor Along Continental Margins.of Seafloor Along Continental Margins.

Oxygen Minimum Zones (<0.5 ml/l) Touch 1,148,000 kmOxygen Minimum Zones (<0.5 ml/l) Touch 1,148,000 km22 of Seafloor Along Continental Margins.of Seafloor Along Continental Margins.

31% in eastern Pacific Ocean

59% in Indian Ocean

10% in southeastern Atlantic

31% in eastern Pacific Ocean

59% in Indian Ocean

10% in southeastern Atlantic

Helly & Levin 2004Helly & Levin 2004

Recovered with Nutrient ManagementRecovered with Nutrient Management

58 systems have responded positively.