Thursday, 7 May 2009

Ocean acidification

I just came across yet another powerful appeal from scientists in response to rising CO2 levels - this one specifically on the problem of ocean acidification. As CO2 dissolves into seawater, it reacts to form carbonate and bicarbonate ions. Adding more CO2 changes the balance between these ions, and that lowers the pH of the water.

Seawater is naturally slightly alkali, but we have witnessed a drop in pH (lower pH = more acidic = less basic/alkali) of around 0.1 units of pH, from 8.2 to 8.1. That may not sound like much, but it is enough to affect marine organisms, and the effect is projected to worsen as CO2 emissions continue in the future.

Oceanographers have been reporting on this issue for some time now, and have expressed concern about the potential damage to marine ecosystems. The Monaco Declaration of January 30, 2009 was an attempt to highlight these serious concerns, bringing together some 155 oceanographers from 26 countries taking part in the ASLO Aquatic Sciences Conference.

The group have started an extensive website with background information on the problem, news on current research and goals for future work.

I quickly checked the list of signatories against my list of climate scientists, and found 16 I'd already listed. Oceanography is an allied discipline to climate science, given the central role of the ocean in the carbon cycle. Oceanographers appreciate the ecosystem risks inherent in rapidly forced changes to ocean pH that come with spiking CO2 in the atmosphere.

Overall, marine life is one of the hidden victims of carbon pollution. The oceans are under assault on so many fronts, from runoff of pesticides, fertilizer and general contaminants, through overfishing, fish farms causing outbreaks of fish lice and releasing antibiotics, shrimp farming driving destruction of mangrove forests needed as nurseries by many marine species, massive buildup of non-biodegradable plastic garbage (shopping bags, lost fishing nets, etc.) that are ingested by seabirds, turtles and fish, plus now water temperature changes, sea level rise and acidification, all piled one on top of the other. There's a horrendous negative synergy compounding between all these separate ways we impact marine life. All this takes place out of sight of most of us, largely unreported and unnoticed.

Losses of both subsistence and commercial fisheries threaten economic disaster in coastal communities worldwide. It's time for us to wake up to what's happening below the waves. I urge everyone to read the Monaco Declaration and look through the website. For more news on this topic, see Science Daily

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