Ocean Chemistry on EARTH Magazine

Congress, states look to address impacts of ocean acidification

Tue, 16 Oct 2018 10:46:56 -0400

Shellfish such as oysters are a big business in the Pacific Northwest, but some places have seen mass mortalities of larvae in recent years due to acidic oceans. Credit: Rick Obst, CC BY 2.0.

Global ocean chemistry is changing at a historically unprecedented rate, with rising ocean acidity threatening populations of shellfish and other marine species worldwide. Recent observed changes in ocean chemistry off U.S. coasts, particularly along the shores of Alaska, California, Oregon and Washington, where fisheries are already being affected, have scientists studying the potential impacts, fishermen worrying about their livelihoods, and politicians pushing for action.

Gulf Stream eddies transport iron to North Atlantic subtropical gyre

Tue, 16 Oct 2018 10:20:31 -0400

New research shows that counterclockwise-rotating cold eddies are transporting iron from the Gulf Stream into the North Atlantic subtropical gyre. Credit: NASA Goddard Space Flight Center Scientific Visualization Studio.

Dust from the Sahara Desert is a major supplier of iron to the North Atlantic subtropical gyre — the huge circular ocean current stretching between North America and the west coasts of Africa and Europe — where cyanobacteria use the scarce nutrient to fuel nitrogen fixation, which then fertilizes other organisms at the base of the marine food chain. Now, researchers have discovered that eddies spinning off the Gulf Stream also transport iron to the northwestern edge of the gyre.

XPRIZE offers new ocean health awards

Tue, 29 Oct 2013 18:45:35 -0400

The newest XPRIZE will be awarded for studying ocean acidification. Jerry Reid, U.S. Fish and Wildlife Service

XPRIZE, the organization that used competition to propel the development of private space travel and super-efficient vehicles, is now making a commitment to improving ocean health.

Fish guts can alter ocean's chemistry

Thu, 05 Jan 2012 06:41:58 -0500

The ocean’s surface waters contain many more microorganisms than fish — and so for years, the carbonate-shelled microorganisms were thought to be the main contributor to the carbonate chemistry in deep ocean waters. Now, new research suggests that the tiny pellets that most bony fish produce in their guts can affect the chemistry of the oceans.

Shell-shocked: How different creatures deal with an acidifying ocean

Thu, 05 Jan 2012 06:41:58 -0500

Ries and one of his students collect specimens. Justin B. Ries

An aragonite conch shell reared under current atmospheric carbon dioxide levels (400 ppm) appears normal, but... Justin B. Ries

...when reared under elevated (2,850 ppm) levels, it shows clear signs of dissolution, especially at the upper lip of the shell. Justin B. Ries

An aragonite quahog shell reared at current (400 ppm) atmospheric carbon dioxide levels shows well-formed ridges. Justin B. Ries

Under elevated (2,850 ppm) carbon dioxide, however, the ridges on the shell are nearly dissolved away. Justin B. Ries

A tropical pencil urchin (high-magnesium calcite shell) reared under current (400 ppm) atmospheric carbon dioxide conditions still has well-formed spines. Justin B. Ries

When reared at elevated (2,850 ppm) carbon dioxide, however, another urchin's spines are nearly dissolved away. Justin B. Ries

Justin Ries look at 18 species of marine calcifiers, including crustaceans, corals, bivalves, gastropods, coralline algae and urchins. Justin B. Ries

Staghorn corals, such as these off of Belize, are more vulnerable to ocean acidification because they build their shells from aragonite, not calcite. Castillo, UNC-Chapel Hill

To survive in the ocean, soft-bodied organisms must possess one of five traits: big teeth, toxic flesh, invisibility, quickness or a hard shell. Most marine organisms that employ the latter, called calcifiers, build their hard shells from the mineral calcium carbonate. However, increasing atmospheric carbon dioxide levels are making the oceans more acidic — which, in turn, is reducing the concentration of carbonate ions dissolved in seawater that organisms use to build their protective shells and skeletons. Calcifying marine organisms — such as clams, crabs, corals and conchs — may soon find themselves short on building material.