The extent to which changes in pH affect a ligand’s ability to bind Fe depends on the number of protons (H+) released upon dissociation of Fe from the ligand (Y). The dissociation reactions can be written in a simplified but general form as:

FeY + 3H2O = Fe(OH)3 + HxY + (3–x)H+

The number of protons released varies between 3 (e.g., for the tetracarboxylate EDTA) and 0 (e.g., for the bis-catecholate azotochelin), and depends on the acidity of the binding moieties, the affinity of the ligand for other metals such as Ca2+ and Mg2+. Consequently, the effective binding strength of ligands that release more protons is more sensitive to changes in pH. In field manipulation experiments, a slower rate of Fe uptake by Thalassiosira weissflogii, with decreasing pH, was observed in both coastal and oceanic Atlantic surface water samples where Fe was bound to natural Fe-chelating ligands (Figure). This result is in agreement with the laboratory data, though the magnitude of the pH effect on the uptake of Fe was modest, suggesting that little of the Fe was bound to carboxylic acid moieties or other ligands that release protons upon dissociation in the field samples (Shi et al., 2010).

We note that the decrease in Fe bioavailability caused by the change in Fe chelation at low pH is only one of several potential effects that ocean acidification may have on Fe limitation of phytoplankton in the oceans. For example the rate of dissolution and precipitation of Fe oxides particles, through thermal or photochemical mechanisms, may also change and, perhaps, compensate for the increase in Fe complexation.

References

Field, C., et al. (1998). Primary production of the biosphere: Integrating terrestrial and oceanic components. Science 281:237-240.
Martin, J. and Fitzwater, S. (1988). Iron-deficiency limits phytoplankton growth in the Northeast Pacific subarctic.
Nature 331:341-343.
Rue, E. and Bruland, K. (1995). Complexation of iron(iii) by natural organic-ligands in the central North Pacific as determined by a new competitive ligand equilibration adsorptive cathodic stripping voltammetric method. Mar Chem. 50:117-138.
Shaked, Y. and Lis, H. (2012). Disassembling iron availability to phytoplankton. Front Microbiol. Chem. 3:123.
Shi, D., et al. (2010). Effects of ocean acidification on iron availability to marine phytoplankton. Science 327:676-679.

Shi D., Xu Y., Hopkinson B. M. & Morel F. M. M., 2013. Effects of ocean acidification on iron availability to marine phytoplankton. SOLAS NEWS 15, Summer 2013: 8-9. Article.

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Climate change is surely the looming disaster of our time.

Scientists say it’s inevitable that sea levels will rise 2 1/2-6 1/2 feet — sufficient to endanger or wipe out many cities. One scientist believes that in the long-term, 69 feet of sea level rise is inescapable.

And the source of the swelling oceans — rising temperatures — will stress the nation’s food system, while the increasing number of devastating storms will place an economic burden on a nation reeling from disaster to disaster, patching its wounds without effecting meaningful change.

It’s tempting to dismiss these projections as hysterical. That life as we know it could change so dramatically, so quickly, seems impossible. But on this topic, the scientific community (if not the political one) speaks with one voice.

Despite the preponderance of evidence — rising temperatures, powerful storms, droughts and fires — no significant action has been taken that would limit the impacts of climate change. Until last Tuesday.

President Barack Obama delivered a bold proposal for a set of regulatory changes that could turn the U.S. from its headlong rush into disaster. This is the course our nation must take if we are to preserve our way of life, and we’re energized to see the president championing such vital reform.

Obama’s plan calls for carbon pollution standards for new and existing power plants, efficiency standards that would reduce carbon pollution by at least 3 billion cumulative metric tons by 2030, fuel economy standards for heavy duty vehicles, the reduction of greenhouse gases and the development of a comprehensive methane strategy. It also provides federal support for local investment to mitigate the worst impacts of climate change.

The plan is sure to impact the way Americans live — or at least the way we pay bills. But that’s preferable to the alternative.

It won’t be easy to turn the nation from habits we’ve indulged for decades, though the true costs of capping carbon emissions are still unknown, and likely won’t be as severe as naysayers’ predictions. (Remember: Cap and trade was offered during the George H.W. Bush adminsitration as a “conservative” alternative to harsher regulation; now the nation’s right wing villifies it as a kind of commie profit-killer. Truth is often the victim of political rhetoric in this debate.)

But for that reason — not to mention that some obdurate lawmakers still deny the basic facts of climate change endorsed by the entire scientific community cling — the president is unlikely to find support in the U.S. Congress for the path we believe he must pursue.

Indeed, some members of Congress have made their careers by obstructing just such measures. Sadly, many of those whose denials of the causes and impacts of climate change ring the loudest represent the coastal areas most vulnerable to rising seas, an act of self-immolation that’s impossible to understand.

Obama’s climate change plan was heralded by these intransigent members as “job killing,” irresponsible and an abuse of executive fiat. (“War on coal” we’ll accept — the plan does take aim at coal, but 38% of greenhouse gas emissions are caused by power plants, most of which burn coal; the next biggest culprit is transportation, accounting for 31%. And these changes needn’t kill jobs — developing alternative energy technologies should provide new sources of employment.)

As a steward of America and American resources, for Obama to sit this one out is unacceptable. And remember that late in the 2012 presidential campaign, it was Obama’s promise to deal with climate change that wooed some unsure voters to his side. So what’s a responsible president to do?

Well, the president says he doesn’t need Congress. Rather, Obama says the broad reforms he envisions can be implemented by executive order, expanding the U.S. Environmental Protection Agency’s regulatory oversight of pollution to include carbon emissions, a use of the executive order is sure to prompt legal and political battles. It’s also worth nothing that Obama is the second American president to define the powers of the executive in broad terms, insisting that the office carries authority and autonomy traditionally not exercised by American presidents.

Obama’s willingness to circumnavigate Congress is a regrettable necessity.

In an ideal world, lawmakers would be swayed by the preponderance of scientific evidence, reach consensus and move to enact regulations that protect our environment. But that’s not what has happened. For a legislator to accept that climate change is happening has become a political, not scientific decision.

And while we’re wary of the increasing power of the presidency, what could be a more appropriate use of that power than to turn the country from environmental devastation?

According to the climate scientists they are just natural weather events.

climate disasters – hahahahaha

He meant storm damage.

Symptoms Of Climate Change
— stevengoddard
Be on the lookout for these :

Warm temperatures
Cold temperatures
Mild temperatures
Snow
Lack of snow
Rain
Lack of rain
Tornadoes
Lack of tornadoes
Hurricanes
Lack of Hurricanes
Hail
Lack of hail
Storms
Lack of storms
Floods
Lack of floods

All of these symptoms are sure fire signs of missing heat, and should be reported to authorities immediately.