Research roundup: distant meetings, carbon sequestration, salt accumulation in Gaza

Peña-Mora is working on a system prototype to incorporate these organizational and physical space issues into a tool that will increase the effectiveness of the space where virtual teams interact. His system will allow people to attend a meeting using personal digital assistants such as iPaqs or Palm Pilots, Java-enabled phones, and personal computers that interact with rich graphical programs such as computer-aided design tools.

Klein and Peña-Mora conclude that while traditional wisdom on forming and leading onsite teams also applies to a globally dispersed team, managing the latter requires more extensive discipline and attention to details because of fewer opportunities for informal interaction.

This research is funded by Ford, Visteon, and Intel under the auspices of the Leaders for Manufacturing (LFM) program and the MIT-Ford Alliance; the NSF, Draper Laboratory and Kajima Corporation from Japan.

Ocean fertilization: not a panacea

A policy tool key to arresting global warming could potentially wreak havoc on the oceans if instituted with no restrictions, warn Prof. Sallie (Penny) Chisholm of CEE and colleagues in the Oct. 12 issue of Science. The article was summarized in Tech Talk on Oct. 18, 2001 by Elizabeth Thomson.

Carbon trading, a feature of the Kyoto Protocol on Climate Change, would limit abiding countries' emissions of carbon dioxide. A country that exceeds its limit could fulfill its commitment by purchasing "carbon credits" from a country that emits less than its quota, or also from commercial industries that have developed ways to remove carbon from the atmosphere, potentially including ocean fertilization.

"Our objections are to commercialized ocean fertilization--the scaled-up consequences of which could be very damaging to the global oceans," write Chisholm and coauthors Paul G. Falkowski of the Institute of Marine and Coastal Sciences and Rutgers University, and John J. Cullen of Dalhousie University in Canada.

Small scientific experiments over the last ten years have shown that fertilizing parts of the ocean increases the number of phytoplankton that remove carbon dioxide from the atmosphere as part of their normal growth. Some of those organisms fall to the bottom of the sea, or are eaten and fall to the bottom as fecal matter, essentially moving carbon out of the air and into the deep.

Entrepreneurs watching these developments have concluded that fertilizing large patches of ocean might therefore be profitable if carbon trading is instituted. "Proponents claim that ocean fertilization is an easily controlled, verifiable process that mimics nature; and that it is an environmentally benign, long-term solution to atmospheric CO2 accumulation," write Chisholm and colleagues.

"These claims are, quite simply, not true," they continue, refuting each argument in turn within the Science article. For example, ocean fertilization is not easily controlled. "A fertilized patch in turbulent ocean currents is not like a plot of land."

Chisholm is particularly critical of claims that ocean fertilization is environmentally benign, particularly given the results of years of research on the negative effects of nutrient enrichment in lakes and coastal waters. She and her colleagues are not against individual experiments using ocean fertilization as a tool for studying the ocean's response to enrichment. Such experiments have already yielded "very exciting results that have contributed to our understanding of the role of the oceans in the global carbon cycle and in regulating climate." Instead, they oppose "the large-scale implementation of ocean fertilization as a carbon sequestration option."

Interest is growing in commercial implementation of ocean fertilization techniques. About seven patents have been filed on different techniques, and at least three small companies have been established. Chisholm recently talked to a representative from Mitsubishi Heavy Industries about ocean fertilization and notes, "So many large companies are watching with interest."

A given company fertilizing a relatively small patch of water would not by itself change the ecology of the oceans. However, "If it's profitable for one, it would be profitable for many, leading to exploitation and a classic tragedy of the commons.

One simple way to avert this potential tragedy is to remove the profit incentive for manipulation of the ocean common. We suggest that ocean fertilization in the open seas, or territorial waters, should never become eligible for carbon credits," they wrote in the Science article.

In September 2001, Jagat Adhiya '01 (SM) and Chisholm wrote a white paper about this topic for MIT's Center for Environmental Initiatives, now the Laboratory for Energy and the Environment. Is Ocean Fertilization Worth Pursuing as a Carbon Sequestration Option? can be downloaded from http://web.mit.edu/chisholm/www/, under "publications."

Salt in Gaza water could halt agriculture in 20 years

adapted from an article by Denise Brehm, MIT News Office

Lack of fresh drinking water poses a serious problem for the million residents of the Gaza Strip, who live and grow food in an area 1/10th the size of Rhode Island. They draw water for drinking and agricultural irrigation from aquifers on the Mediterranean that are becoming saltier each year.

The UN Nations Development Programme and US Agency for International Development currently recommend that Gaza can maintain its freshwater supply by using only an amount less than or equal to its usable annual rainfall. But a study conducted by CEE Prof. Charles Harvey and Annette Huber-Lee '87 (SM) shows that even if the residents stay within those quantity guidelines, the water quality will continue to deteriorate rapidly.

Because of saltwater intrusion from the sea into the aquifer, and recirculation and evaporation losses of pumped groundwater, the water is deteriorating faster than fresh rainwater can desalinate it. Gaza residents must acquire water from beyond their borders, which are closed at present; build a large desalination plant; or eliminate agriculture within the next two decades, said the two researchers.

"We're not talking about a hundred years into the future," said primary author Huber-Lee. "It's reaching a point where you have to decide what you are willing to impose upon people, and without additional sources of water, you finally have to eliminate agriculture."

Agriculture is about 30% of Gaza's gross domestic product. While this percentage has remained steady in the past 20 years, the increasing salinity has affected the types of food grown, eliminating most citrus fruit in favor of salt-tolerant vegetables and flowers.

The aquifer acquires salt in several ways. When water is overpumped from the aquifer, seawater seeps in underground to fill the emptying reservoir. Salt also comes from brackish upstream sources, and from the evaporation of irrigation water and wells that recapture irrigation water. As some of the irrigation water evaporates into the air, salt remains behind in the soil. That salt is then carried by irrigation water back into the aquifer, increasing its salinity with each cycle.

"Families send kids out with two-liter Coke bottles to get water that is less salty for drinking. You can certainly taste the salt, but it's drinkable," said Huber-Lee. "Still, the older people say to me, 'When I was younger, all this water was fresh.'"

Huber-Lee and Harvey built optimization computer models to predict freshwater availability in the Gaza Strip by incorporating numerical modeling of groundwater flow and salt transport in the region with a quantitative economic model of the region's domestic and agricultural water use.

Assuming that the Gaza regional government used only the amount of water renewed by annual rainfall (10-20 inches), the population of the Gaza Strip still would run dangerously low on fresh water within a decade, the researchers said. "Our simulation models indicate that current water use in Gaza is unsustainable with the current population. The steady-state sustainable model shows an extreme solution: the irrigation of crops would have to be stopped immediately and household water use curtailed to sustain water use into the future."

The researchers' transient model looked at how to use the water effectively from year to year. This type of model is the standard approach for evaluating the costs and benefits of water management plans over time, and it places a higher value on agricultural use of water today, regardless of what effect that has on the future. "The 75-year transient model shows that irrigated agriculture can remain, but leaves the groundwater too saline for future generations to use," they wrote.

"The solution is desalination or other new sources of freshwater, together with infrastructure to transport and treat water," said Huber-Lee and Harvey. They estimate that a desalination plant large enough to 50 million cubic meters per year would cost at least $100 million to build and have operational costs on the order of $0.70 per cubic meter of water.

The research was funded by grants from the Dutch Foreign Ministry and the US Environmental Protection Agency. Huber-Lee began working on the Gaza water project while doing her doctoral work at Harvard. She completed the project while working at MIT with Professor Harvey, who was on her doctoral committee.