Green Options

The researchers further warn that increasing temperatures in this vital, globally-extended ecosystem could “reduce the transfer of primary produced organic matter to higher trophic levels” (e.g., such as those that sustain corals and the many species that use them as habitat), interfere with the global carbon pump, and possibly set up a positive feedback mechanism, further increasing atmospheric carbon dioxide.

Sigourney Weaver narrates “Acid Test“, an illuminating and terrifying NRDC documentary that explains how quickly our planet’s oceans are acidifying due to all of the carbon dioxide that we are pumping into our air. This pollution is causing rapid changes in our oceans’ chemistry that will completely disrupt all life on the planet as we know it on a scale that has not been seen for tens of millions of years.

In a possible solution to a marine chemistry mystery that has puzzled scientists for several decades, researchers have now calculated the contribution of teleost fish (bony fish) to marine carbonate (CO3) concentrations. They estimate that such fish secrete up to 15% of the ocean’s carbonate production, through their intestines, or guts (these are conservative estimates; the more liberal estimates show up to 45%).

This is important because sea water is saturated with calcium ions (Ca+2), which must be combined with carbonates to form the shells (as in bi-valves like clams and scallops) and habitat structures (as in gastropods, like conchs, and coral communities) made of Calcium carbonate (CaCO3). CaCO3 is a “neutral” (non ionic/reactive) and stable compound (within normal ocean ph ranges), and, with its plentiful constituent ions (Ca2+ and CO3-), it is an ideal material for marine creatures to utilize in constructing their shells and skeletons.

So-called “dead zones”–patches of ocean lacking aerobic (oxygen breathing) life–will most likely increase due to a rise in carbon dioxide (CO2) concentrations.

Because of CO2 build up in the atmosphere, its level of concentration in the oceans also increases. There, some of the CO2 converts to a simple acid called carbonic acid. (H2CO3).

What is becoming a much-studied phenomenon in recent years, these dead zones of depleted oxygen (02) - typically found at depths between 300 and 600 meters–are the result of several factors working separately and in combination: lower sea surface 02 levels, less heat exchanging (”ventilation”) with mid-level ocean depths due to over-all warming, and “euthrophication events” (an over-growth of a species due to excess nutrients).

Marine biologists have discovered a dense population of mussels (the vent mussel Bathymodiolus brevior, a common, edible bi-valve “shellfish”), carpeting the sides of a submarine volcano, which has survived–despite the highly acidic environment–for the past 40 years. The results of this study were reported in a recent, on-line edition of the Journal Nature Geoscience.

The acidification of ocean habitats due to increased absorption of CO2 (which reacts with water to form carbonic acid) has become an issue of great concern over the past decade. Shellfish and other marine species (like corals and snails) that make their “homes” or shells from carbonates of calcium (CaCO3), are vulnerable to more acidic waters. A lower ph (generally below 8 on the ph scale) marine environment makes calcium ions less available to these creatures to fabricate their fortifications against nature’s predators and chemical forces. The result of this acidic exposure in shellfish is typically a much thinner shell, thus making the creature more susceptible to predation and even disease (as in the case of many corals; see: One Third of Reef-Building Corals Face Extinction Risk ).

Scientists gathering specimens in a submersible off the coast of Hawaii have discovered the oldest living colonial creature on Earth, dated at 4,265 years old.

The geriatric discovery (Leiopathes sp.) is a deep water tree-like coral, which grows only a few micrometers every year. That’s an annual growth rate at around the size of a human blood cell. And the Leiopathes sp. wasn’t the only old creature found. Also discovered was a 2,742 year old gold coral (Gerardia sp.).

The discovery raises needed awareness about the delicate, fragile ecosystems of deep sea reefs, which are endangered due to trawling and global warming.

In terms of promoting and supporting the greatest variety of life, reef corals are the “rain forests” of the oceans.

The corals themselves also have commercial value (for jewelry, aquarium decoration, etc.).  Corals–symbiotic colonies of plant-like and animal-like creatures–have existed on this planet for tens of millions of years. However, some 45% of all coral species went extinct around the same time as the dinosaurs did. Hardest hit were a group of photosynthesizing, algae-harboring corals known as zooxanthellates. The symbiotic , red-brown algae that co-exist with these corals (and provide their energy source) are known as zooxanthellae.

Marine scientists have noted for several years now the spread of a coral disease known as Yellow Band Disease (YBD)–so named for the yellowish bands that spread across coral polyps–but had attributed its spread to thermal stress caused by global warming. Thermal stress is known to weaken much marine life, including corals, shellfish, and some species of zooplankton. But in November of 2008, researchers at Woodshole Oceanographic Institute (WHOI), on Cape Cod, Massachusetts, isolated the bacteria that caused YBD–actually four species of Vibrio bacteria that combine with the indigenous Vibrio bacteria to attack zooxanthellae (see the paper in the Journal of Applied Microbiology).

Ocean acidification, and it’s happening at a much more alarming rate than originally thought, according to a new report.