September 2006, Vol. 18, No.9

Waterline

Waterline - Drug Discovery Team To Explore Newly Discovered Deep-Sea Reefs

In December, University of Miami researchers using advanced sonar techniques discovered new deepwater reef sites 600 to 900 m (2000 to 2900 ft) deep in the Straits of Florida between Miami and Bimini. In May, Harbor Branch Oceanographic Institution (HBOI; Fort Pierce, Fla.) scientists worked with their Miami colleagues to explore these areas for the first time using HBOI’s Johnson-Sea-Link II submersible vehicle.

The goal of the expedition, according to an HBOI press release, was to search for and collect marine organisms from the reefs to test them for the presence of new chemical compounds with the potential to treat human diseases, such as cancer and Alzheimer’s disease. The expedition is being funded largely by the State of Florida’s Florida Oceans Initiative.

“We’ve found incredible and surprising diversity at other deepwater reefs near Miami and Bimini, and some promising potential disease treatments,” said Amy Wright, director of HBOI’s Division of Biomedical Marine Research.

Researchers have suspected since the 1970s that deep reefs lay undiscovered between Miami and Bimini, because pieces of reef-building corals had been brought up using surface-operated dredge and grab sampling equipment. However, just as the majority of the ocean remains poorly mapped and unexplored, these potentially important areas remained unseen, the press release states.
In December, as part of the U.S. National Oceanic and Atmospheric Administration’s Ocean Exploration program, University of Miami researchers, led by geophysicist Mark Grasmueck and geologist Gergor Eberli, began mapping deepwater habitats off Miami and Bimini using an autonomous underwater vehicle equipped with advanced sonar technology.

Miami’s work with the underwater vehicle revealed what appears to be an extensive system of steep slopes and mounds as high as 107 m (350 ft), all of which are likely to harbor a wide array of sponges, corals, fish, and other animals, according to HBOI.

Following two May expeditions and a personnel and equipment turnaround, HBOI researchers returned to the Miami area on a separate expedition in early June to conduct the first in-depth survey of deep reef areas in the region to assess further the ecological importance of the reefs and identify factors responsible for their incredible diversity.

The expedition, whose outcomes at press time had not been reported, had two main goals. First, the team used the underwater vehicle to explore sea-floor areas that appeared most promising, based on their sonar map contours. From this, the team will be able to better predict correlations between map data and biodiversity on the bottom. Ultimately, this will enable them to assess more accurately the ecological importance of the entire area, rather than only the small swaths observed from the submersible vehicle.

During each submersible dive, HBOI experts collected samples of organisms, such as sponges and corals, that will be tested to determine if they or microorganisms living within them produce chemicals with pharmaceutical potential. A key goal is to find and collect organisms that have never been seen, which happens on almost every one of the HBOI team’s expeditions, according to the news release. HBOI’s quest for drugs from the sea began in the early 1980s and has led to the collection of tens of thousands of marine organism samples and the identification of a number of promising potential drugs now in various stages of development for treating cancer, Alzheimer’s disease, malaria, AIDS, and other ailments, the news release says.

Read more about HBOI and its expeditions and research at www.hboi.edu.  

National Guidance Issued To Prepare Ships as Artificial Reefs

 The U.S. Environmental Protection Agency (EPA) and the U.S. Maritime Administration recently released joint guidance recommending environmental best management practices for cleaning ships that are to be sunk as artificial reefs. The guidance, according to EPA, will help ensure that obsolete and decommissioned military and commercial vessels sunk for this purpose will not harm the environment.
The guidance identifies materials or categories of materials that may be on board ships, where the materials may be found, general cleanup performance goals, and information on how to achieve these goals. Verifying that the best management practice goals were met can help support permit and certification decisions for vessel-to-reef projects, an EPA news release states.

See the guidance on artificial reefs at www.epa.gov/owow/oceans/habitat/artificialreefs.

Acid Rain Causing Decline in Sugar Maples

Acid rain, the environmental consequence of burning fossil fuels, running factories, and driving cars, has altered soils and reduced the number of sugar maple trees growing in the northeastern United States, according to a new study led by researchers at Cornell University (Ithaca, N.Y.).

The sugar maple is the most economically valuable tree species in the eastern United States because of its high-priced lumber, syrup, and tourist-attracting fall colors, according to a Cornell press release.
The study, led by Cornell student Stephanie Juice, suggests that acid rain makes the soil more acidic and, therefore, is unfavorable for sugar maple growth. In acidic soils, sugar maples produce fewer seedlings that survive and mature, and more adult trees die, the researchers found. They drew these conclusions after adding nutrients to soil in a test plot and reproducing the favorable soil conditions that existed prior to 20th century industrial pollution. Sugar maples on the plot rebounded dramatically.

The nitric acid and sulfuric acid in acid rain leach calcium from the soil. Calcium is the second most abundant plant nutrient after nitrogen, according to the press release. In addition, the loss of calcium leads directly to more acidic soils, and when soils become too acidic, such trees as sugar maples become stressed and have a harder time growing or producing seeds and seedlings.

The study provides “the most conclusive evidence to date” that the decline of sugar maples is linked to the effects of acid rain produced by human activity, said Timothy Fahey, professor of forest ecology at Cornell and co-author of the study.

The research was conducted at Hubbard Brook Experimental Forest, a 3160-ha (7808-ac) reserve near North Woodstock, N.H., where scientists have measured soil composition for the past 50 years, the news release notes. The scientists added nutrients in a test plot to replicate soil conditions that existed prior to the loss of sugar maples during the past 25 years.

The study used two 10-ha (25-ac) watersheds. On one site, a calcium-rich mineral called wollastonite was spread in pellet form by helicopter in October 1999. The other site served as a control. While the pellets dissolve slowly during a 5- to 10-year period, the researchers found that by summer 2002, the soil acidity in both the top and lower layers of the test plot neutralized from being highly acidic to more acceptable levels for sugar maples. The researchers also found that by the second year, calcium levels in the maples’ leaves had risen.

Acid rain also increases levels of the trace nutrient manganese in the soil, which can be toxic to trees in higher doses, the news release states. By years 4 and 5, manganese in the leaves had declined to healthier levels. Seed production and the density and size of sugar maple seedlings all increased in the few years following treatment, compared with the untreated neighboring plot.

The researchers also found that the communities of mycorrhizae — soil fungi that help provide more nutrients to plant roots — were substantially greater around the roots of both seedlings and mature sugar maples in the treated plot. Future research will explore the relationship between mycorrhizae and acid rain.

Though pollution control legislation has helped reduce sulfuric acid by one-third since its high point in the 1960s, nitric acid from automobiles has not significantly declined.

For more information, contact Fahey at tjf5@cornell.edu