The ocean surface is 30 percent more acidic today than it was in 1800, much of that increase occurring in the last 50 years -- a rising trend that could both harm coral reefs and profoundly impact tiny shelled plankton at the base of the ocean food web, scientists warn.
Despite the seriousness of such changes to the ocean, however, the world has yet to deploy a complete suite of available tools to monitor rising acidification and other ocean conditions that have a fundamental impact on life throughout the planet.
Marine life patterns, water temperature, sea level, and polar ice cover join acidity and other variables in a list of ocean characteristics that can and should be tracked continuously through the expanded deployment of existing technologies in a permanent, integrated global monitoring system, scientists say.
The Partnership for Observation of the Global Oceans (POGO), representing 38 major oceanographic institutions from 21 countries and leading a global consortium called Oceans United, will urge government officials and ministers meeting in Beijing Nov. 3-5 to help complete an integrated global ocean observation system by target date 2015.
It would be the marine component of a Global Earth Observation System of Systems under discussion in Beijing by some 71 member nations of the intergovernmental Group on Earth Observations.
The cost to create an adequate monitoring system has been estimated at $10 billion to $15 billion in assets, with $5 billion in annual operating costs.
Some 600 scientists with expertise in all facets of the oceans developed an authoritative vision of characteristics to monitor at a 2009 conference on ocean observations.
Dr. Trevor Platt, Executive Director of POGO, Plymouth Marine Laboratory, UK said, "We rely on the oceans for transportation, protein, pharmaceuticals, minerals and hydrocarbons. But we do not know nearly enough about how the oceans are changing. The world's coastal fringes, where 40 percent of humanity resides, suffer increasingly costly storms and flooding. Without the proper information, we are powerless to anticipate and prepare for what may come in the future. Our best defense is an observing network for the global ocean to warn of trouble."
Furthermore, as documented in the forthcoming proceedings of the 2009 conference (to be published shortly by the European Space Agency), the value of such information to the world's financial interests and to human security would dwarf the investment required.
"Although the US and European Union governments have recently signaled support, international cooperation is desperately needed to complete a global ocean observation system that could continuously collect, synthesize and interpret data critical to a wide variety of human needs," says Dr. Kiyoshi Suyehiro, Chairman of POGO.
"Most ocean experts believe the future ocean will be saltier, hotter, more acidic, and less diverse," states Jesse Ausubel, a founder of POGO and of the recently completed Census of Marine Life. "It is past time to get serious about measuring what's happening to the seas around us."
The risks posed by ocean acidification exemplify the many good reasons to act urgently.
POGO-affiliated scientists at the UK-based Sir Alister Hardy Foundation for Ocean Science recently published a world atlas charting the distribution of the subset of plankton species that grow shells at some point in their life cycles. Not only are these shelled plankton fundamental to the ocean's food web, they also play a major role in planetary climate regulation and oxygen production. Highly acidic sea water inhibits the growth of plankton shells.
The Foundation says the average level of pH at the ocean surface has dropped from 8.2 to 8.1 units, "rendering the oceans more acidic than they have been for 20 million years," with expectations of continuing acidification due to high concentrations of carbon dioxide in the atmosphere.
Because colder water retains more carbon dioxide, the acidity of surface waters may increase fastest at Earth's high latitudes where the zooplankton known as pteropods are particularly abundant. Pteropods (see links to images below) are colorful, free-swimming pelagic sea snails and sea slugs on which many animals higher in the food chain depend. Scientists caution that the overall global marine impact of rising carbon dioxide is unclear because warming of the oceans associated with rising greenhouse gases in the air could in turn lead to lower retention of carbon dioxide at lower latitudes and to potential countervailing effects.
Says Foundation Director Dr. Peter Burkill: "Ocean acidification could have a devastating effect on calcifying organisms, and perhaps marine ecosystems as a whole, and we need global monitoring to provide timely information on trends and fluxes from the tropics to the poles. Threatened are tiny life forms that help the oceans absorb an estimated 50 gigatonnes of carbon from Earth's atmosphere annually, about the same as all plants and trees on land. Humanity has a vital interest in authoritative information about ocean conditions and a global network of observations is urgently needed."
Ocean conditions that require monitoring can be divided into three categories:
Benefits of the comprehensive ocean system envisioned include:
Says Dr. Suyehiro: "What happens in the world's oceans profoundly affects the success of life throughout the Earth. We now have remarkable and proven ground-based, ocean-drifting, air-borne and space-based technologies to measure and report changing ocean conditions quickly, often in real-time. The right kind of data streams from the ocean will help us forecast regime shifts in weather patterns over continents and their consequences for agriculture, fisheries, tourism and other sectors. The value of the knowledge within our reach -- to human health, security and commerce -- is overwhelmingly large relative to its cost."
"The situation of scientists today is akin to that of a doctor schooled in the range of technologies that could record a patient's vital signs, sound an alarm when required, and suggest remedial options -- if only we would make the investment."
Says Tony Knap, Director of the Bermuda Institute of Ocean Sciences and a leader of POGO: "The top three meters of the oceans hold as much heat as Earth's atmosphere and changes in marine conditions are felt on land in profound ways. To obtain clear warning of weather-related disasters, we need to monitor oceans in an integrated, continuous and systematic manner. It will not be cheap, but it has to be done."
Elements of the ocean monitoring system in place today include:
To embrace the challenge of monitoring ocean life, world experts are formally puzzling through a recommended installation sequence; in other words, what, where and how many "life gauges" are top priorities in the proposed system.
The parts of the system now installed represent only a fraction of what's required for authoritative accuracy and global perspective, according to POGO. Needed are expansion of the array of the technologies above as well as:
The in situ observations would complement a suite of satellite-borne devices tracking sea-surface roughness, temperature, currents, ice cover and shifting distributions of marine plants. Satellites provide wide aerial coverage, but provide little information from deep within the ocean; hence the need for both types of observations.
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