Marine chemist Richard Feely, a senior scientist with the National Oceanic and Atmosphere Administration, has been collecting water samples in the North Pacific for over 30 years. He’s observed a decrease in pH at the upper part of the water column, notably the region where carbon dioxide from automobile exhaust, coal-fired power plants, and other human activities has collected. This surface water is now acidic enough to dissolve the shells of some marine animals such as corals, plankton, and mollusks in laboratory experiments. Feely’s findings are just one sign of a troubling global phenomenon called ocean acidification.

We spend a lot of time worrying about carbon dioxide in the atmosphere, as a form of pollution and also as a key greenhouse gas that traps solar heat. But we pay less attention to the effects emissions have in the ocean. There is no debate that rapidly increasing seawater acidity is the result of man-made carbon emissions.

“The chemistry of the uptake of carbon dioxide and its changing pH of seawater is very, very clear,” explains Feely.

The oceans absorb an estimated 22 million tons of CO2 from the atmosphere every day. This buffers the greenhouse effect by drawing the planet-warming gas out of the atmosphere and storing it in water, but at a great cost to ocean life. This carbon mixes with the salt water to create carbonic acid, which immediately breaks down, forming bicarbonate and hydrogen. And this excess hydrogen increases the water’s acidity.

Higher acidity, in turn, makes life difficult for marine animals by hampering their ability to form shells and skeletons. For microscopic plankton and many other species at the base of marine food chains, this means slower growth and potential population decline. These problems trickle up to affect the large fish that depend on smaller organisms for food.

Acidification also causes some coral species to grow more slowly or disappear. Since coral reefs support 25 percent of the ocean’s species of fish, this spells widespread trouble. Marine ecosystems are so interconnected, in fact, that scientists cannot predict the full effects of acidification. They only know that changes in the availability of food and in community structure can scale up quickly.

Carbon emissions released since the start of the industrial revolution have sped the process of ocean acidification, leaving little time for plants and animals to adapt to altered conditions. Scientists now anticipate an average pH decline from 8.1 units to 7.8 in oceans by the end of this century. According to John Guinotte, a marine biogeographer at the Marine Biology Conservation Institute, in Washington, D.C., human activity is now increasing the amount of CO2 in the ocean at an accelerating rate. “Unless we alter human behavior,” he warns, “we may experience irreversible shifts in the marine environment that can have dire consequences for life on Earth.”

An international team of marine biologists recently traveled to Papua New Guinea where excess CO2 released from volcanic activity has already decreased local ocean pH to the levels that are expected globally by 2100. In this area, they found that more than 90 percent of the region’s coral reef species were lost. The study provided a glimpse of how oceans might one day change around the world and serves as a warning that we must curb carbon emissions as quickly as possible.

For us on land, ocean acidification will do more than raise the cost of seafood. A decline in reefs worldwide, for example, would make coastal communities more vulnerable to storm surges and hurricanes. Meanwhile, the fishing and shellfish industries stand to lose hundreds of millions of dollars, and countless jobs, because of acidification’s effects on shellfish, as well as associated changes in the populations of larger species. In the United States, oyster hatcheries in the Pacific Northwest have already experienced reduced shell growth due to higher acidity levels. No one can predict the full consequences of ocean acidification, but it’s clear our own species will experience them in many ways.

“About one billion people throughout the world depend on protein from fish for survival, so we have to think about what this means for international food security,” explains Feely.

Carbon emissions clearly cause problems beyond climate change. And because sea waters mix slowly, whether or not we reduce emissions now, acidification will continue for centuries. If Congress cannot act to restrict emissions, it must as least ensure that marine scientists have the funding needed to study the effects of changing pH on different marine species and, in the decades ahead, to search for ways to mitigate the effects of ocean acidification.

Even the most promising young scientists, those with the natural ability and discipline to fulfill their potential and become tomorrow’s leaders in innovation—and eventually upon which the nation’s future depends—are struggling.

Appearances, though, can be deceiving. Mounting evidence suggests that looming institutional shortcomings are eroding the ability of the so-called “science pipeline” to produce a healthy future national science infrastructure—and unless we shift the traditional paradigm rapidly, the consequences could be dramatic. Two recent studies underscore this point: One, from the National Institutes of Health, reports that the current generation of young scientists may be turning away from careers in research due to funding issues and the need for institutional change. Concurrently, the American Academy of Arts and Sciences’ new report, “ARISE: Advancing Research In Science and Engineering,” concludes that early-career researchers face greater challenges today than ever. The continual and grueling search for funding, the Academy suggests, fosters overly conservative decisions about laboratory research directions, which in turn impede the impact of government-funded science and thwart the careers of younger talents.

It’s no secret that many young people who otherwise might nourish an interest in science—or in academia generally—get drawn away from the ivory towers to pursue private sector opportunities promising higher salaries and better possibilities for family and lifestyle. For those still hoping to advance in science, the practical barriers that our system currently creates are tremendous; and what’s more, all signs suggest they’re getting worse.

Science graduates intent on the journey to a professorship must first get through a postdoctoral appointment (or three), and sometimes a multiyear probationary period. In a 2005 survey, the average amount of time for holding a postdoctoral position was 3.8 years. All the while, salary is low and work hours are long. There is tremendous pressure to publish….or perish. And only then does the search for a faculty position begin—a search that keeps growing tougher.

The National Science Foundation reports that between 1972 and 2003, the share of recent doctorate holders hired into full-time faculty positions fell from 74 percent to 44 percent. During the same period, the number of science and engineering Ph.D.s in postdoctoral positions rose from 13percent to 34 percent. Even as we’re producing more advanced science graduates than ever, the traditional academic trajectory affords fewer and fewer options.

And that doesn’t even begin to address the difficulty of winning tenure. Between 1993 and 2003, the number of faculty-level jobs at research universities without the possibility of tenure increased from 55 percent to 70 percent. Most foreboding of all, the probability that a Ph.D. recipient under 35 years old will obtain a tenure-track job fell to 7 percent. In short, we’re shutting down opportunity for the vast majority of young American scientific talents.

And it’s not just happening because of a dearth of faculty positions, tenured or otherwise. Trends in the availability of research funding show a similar constriction of opportunity. Since 2003, the rate of funding for independent grants has fallen dramatically, and young scientists have been most affected. Today, less than three percent of the main independent research grants go to scientists under the age of 35, and the average age of first-time awardees is 43. And so at what should be the most productive period of their careers, new faculty must dedicate an enormous amount of time to submitting repeated grant applications. In fact, according to the ARISE report, new investigators are submitting twice as many proposals as established investigators and typically receive substantially smaller awards.

All of which means that at a time when they should focus on learning and honing their skills, young scientists must instead compete with senior scientists for funding. Indeed, given that an investigator’s scientific status derives in part from how many grants he or she obtains, it may not always in the best interest of mentors to pass on all their accumulated knowledge to students—for fear of losing future funding opportunities themselves.

In some cases, one can even single out an apparent hoarding of research funds. In 2007, two hundred scientists received six or more NIH grants, and a single investigator won 32 grants, while many others got close to ten. An NIH advisory panel has recommended that grant awardees devote at least 20 percent of their time to each, but these numbers show a clear disconnect between intentions and reality. These multiple awards are going to established investigators—who are certainly not spending one fifth of their time per study—while younger scientists would probably devote more energies to the work. Thus, laboratories around the country are fostering a “survival of the oldest” dynamic.

Particularly in the biomedical field, this opportunity gap between young and old is a quirk of politics. When NIH funding doubled between 1998 and 2003, many new Ph.D. positions were created, which in turn allowed established investigators with more students to submit better proposals. But then in 2003, NIH funding leveled off. Older scientists now had a successful history based on the funding boom, and fallout today reveals significantly more scientists over the age of 70 finding support compared to those under the age of 30. Perhaps the situation is best summed up by NIH Director Elias Zerhouni, who wrote in a recent Science magazine Policy Forum article, “Like farmers during difficult times, we should not ‘eat our seed corn,’ but protect it.”

Thus, the frustrating pursuit of funding in science severely constrains productivity and creative departures—and the United States will suffer from the loss of a healthy research enterprise if job market, tenure, and funding patterns continue to prevent innovative young researchers from pursuing their most daring ideas. While we obviously need to create some hurdles so as to identify the most gifted and dedicated minds, our current model goes far beyond a reasonable winnowing process. Even the most promising young scientists, those with the natural ability and discipline to fulfill their potential and become tomorrow’s leaders in innovation—and eventually upon which the nation’s future depends—are struggling.

Sheril Kirshenbaum is a marine biologist at the Nicholas Institute for Environmental Policy Solutions at Duke. She blogs at The Intersection with Chris Mooney.