The gloomy future of the ocean (part 1)

Terric Klinger began to wonder about the future of kelp sex.

Klinger, of the University of Washington in Seattle, studies the kelp wing and kelp crawl, a species that spreads its leaves like rubber from the ocean floor off the Pacific coast. The leaf strips of kelp are not in need of any seductive action, but only broken into pieces of chocolate.

These pieces release spores. They swim away and settle on a surface and start the next generation. The new small kelp root does not look like the same species, or even with them, with their parents. Baby kelps only grow in rows of cells, but the problem here is about their gender.

'Only those of us who have spent so much time watching them can distinguish males and females.' Sophisticated fibers of female algae form eggs and release pheromones to invoke sperm from male algae.

Genital fibers have kept kelp species alive for millennia, but Klinger says she wants to know what happens when carbon emissions are altering the chemical structure of seawater.The complex reproductive cycle of kelp is an example of a sophisticated system that can withstand enormous impacts from seemingly small changes of seawater chemical composition.

This chemical composition has gradually changed due to the increasing concentration of CO ₂ emissions in the atmosphere from human activities. According to Richard Feely, the National Oceanic and Atmospheric Administration, Seattle, not all CO2 emissions from burning fuels remain in the air. The ocean has absorbed half of the carbon dioxide from burning fuel since the beginning of the industrial age. The ocean collects about 22 million tons of CO2 every day.

This absorption has caused a process that scientists call ocean acidification . This is just the term. The ocean environment is not acid at the moment and Feely or other scientists do not expect seawater to become acid in the future. However, elevated CO ₂ is driving the ocean toward the acidic environment on a pH scale. Feely said that by the end of the century, about 100 meters, or more, the surface of the seawater would be more acidic than at any time in the past 20 million years.

Klinger is just one of many scientists trying to figure out what changes in seawater chemistry will cause algae, corals, fish and other marine life. Fibers of winged kelp and kelp develop significantly slower in acidic seawater, reported Klinger at the 2008 Marine Science meeting in Orlando, Florida.

Biologists are discussing what chemical change will do for marine life: it seems to be bad news for calcium-using organisms and is a new beginning for viscous rocks. It may begin a period of simplification of the ocean ecosystem. In any way, everyone agrees that burning fuels will produce a new type of ocean by changing the chemistry and biology of the ocean.

The sea environment is changing

Scientists believe that in the oceans today chemical changes are taking place, although at first this change seems very small.

Feely placed the top layer of seawater at 8.10 on the pH scale. This scale moves from 14 to 0 and describes the concentration of hydrogen ions. White water, classified as neutral, lies at 7. Lower values ​​imply increasing acidity and more hydrogen ions. Feely said that since the industrial phase began, the pH of the seawater had slipped about 0.11 per pH unit.

According to a 2005 report on ocean acidification by the Royal Society of the United Kingdom, it was a significant change. The pH scale is logarithmic, so level 7 means that the amount of ion is 10 times higher than the level of 8. The industrial age has increased the concentration of hydrogen ions by about 1/3.

The change in pH since this century may be even bigger. The current scenario of carbon emissions will push the ocean surface pH to as low as 0.3 or 0.4 units by the end of the century.

However, this is not an acidic environment. In order for the ocean pH to be below 7, it is predicted that humans must burn all the carbon from the fuel on the earth plus a relative amount of methane hydrate.

GeoEye The blooming of single-celled algae phytoplankton (light blue water) in the Bering Sea from the banks of the Aleutian Islands in July 1998 can be observed through satellite images.The changes in the chemical environment of seawater are small but can also have a big impact on similar small organisms.(Photos: (SeaWiFS) / NASA / GSFC, GeoEye)

However, describing this process as ocean acidification is not wrong.Seawater is acidified in the sense that it is climbing up the acid level on the scale. Even if the ocean is not too acidic, even small pH changes can have a big impact on marine life.

Marine species from corals to snails or floating creatures called coccolithophores create carbonate calcium structures. Increasing CO2 makes this more difficult.

An important component of calcium carbonate is carbonate ion, CO ₃ ^-2 . When this ion comes into contact with water, CO ₂ forms carbonic acid H ₂ CO ^₃ . ' It's the same as adding carbon dioxide to carbonated drinks so it foams.' Carbonic acid decomposes, releasing hydrogen ions that react with water carbonate ions, making it difficult for calcium carbonated species like corals to grow. Feely said that carbon density in warm water in coral habitats has decreased by 16% since pre-industrial times.

Dangerous for corals

The pink coral polyp species (Hainan, China) will have difficulty in forming coral reefs when carbon emissions change the ocean's chemical composition.(Photo: iStockphoto)

According to Ove Hoegh-Guldbergh, University of Queensland, St. Lucia, Australia, the future of coral depends on the amount of CO ₂ present in the atmosphere . At the annual meeting of the American Association for the Advancement of Science in Boston, he mentioned his latest work. In Science on February 14, he and 16 other scientists summarized their predictions about the three possible futures of corals.

Hoegh-Guldbergh offers a set of three photos of coral reefs. In the first picture, multicolored fish swim around on brown coral reefs crowded together, a classic postcard of a diverse coral reef. This scene represents a world where people also emit less CO2. Air CO ₂ is stable at 380 parts / 1 million (ppm). Some changes in the ocean ecosystem are now unavoidable, but for the majority of the current reefs in the world, coral is still the dominant species.

The second image depicts this world when the amount of atmospheric CO2 has soared between 450 and 500 ppm. The ocean grass trail used to be a friendly place with reefs that became so hungry and carbonate that more and more corals within the top 100m of seawater could not be added to the coral frame. The multicolored fish narrowed down because this range of rocks no longer provided shelter for them. Large and bristling microalgae filled the abandoned coral frame, making it more difficult for coral spores to settle.

The last image is the world with a CO ₂ content of over 500, showing a murky slope full of rubble. 'You get oil-filled rocks.'

This ocean perspective could become a reality by the end of the century even when the Intergovernmental Panel on Climate Change is optimistic that the future of atmospheric CO2 content is around 550 ppm by 2100 .