Clean Fuels Could Reduce Deaths From Ship Smokestacks By 40,000 Annually

Rising levels of smokestack emissions from oceangoing ships will cause an estimated 87,000 deaths worldwide each year by 2012 — almost one-third higher than previously believed, according to the second major study on that topic. The study says that government action to reduce sulfur emissions from shipping fuel (the source of air pollution linked to an increased risk of illness and death) could reduce that toll.

James Winebrake and colleagues note that most oceangoing ships burn fuels with a high sulfur content that averages 2.4 percent. Their smokestacks emit sulfur-containing particles linked to increased risks of lung and heart disease. A 2007 study by the researchers estimated that about 60,000 people died prematurely around the world due to shipping-related emissions in 2002. The new study estimates that the toll could rise to 87,000 by 2012, assuming that the global shipping industry rebounds from the current economic slump and no new regulation occurs.
Policymakers now are considering limiting ships emissions by either restricting sulfur content in fuel or designating air pollution control areas to reduce air pollution near highly populated coastal areas. Requiring ships to use marine fuel with 0.5 percent sulfur within 200 nautical miles of shore would reduce premature deaths by about 41,200, the study concludes. Lower sulfur reductions could reduce deaths even further, they say, adding that designated emission control areas will also have a positive impact.
Journal reference:
Winebrake et al. Mitigating the Health Impacts of Pollution from Oceangoing Shipping: An Assessment of Low-Sulfur Fuel Mandates. Environmental Science & Technology, 2009; 43 (13): 4776 DOI: 10.1021/es803224q
Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Unique Acoustic System Protects Manatees From Injuries And Death

Researchers at Harbor Branch Oceanographic Institute at Florida Atlantic University have developed and improved upon a unique acoustic system designed to keep manatees from being injured or killed by flood gates and boat locks. Locks are used on sections of a canal or river that may be closed off by gates to control the water level to enable the raising and lowering of boats passing through.

The “Manatee Acoustic Detection Sensor Protection System” is composed of an array of unique acoustic transmitters and receivers that provide non-contact detection of manatees as they pass through the gates of the lock. When a manatee blocks the acoustic beams, which they cannot hear, the gates stop and remain open long enough to allow them to pass through safely. Harbor Branch recently received a $5.8 million federal contract from the U.S. Army Corps of Engineers to install the system in southern Florida on the six navigation locks around Lake Okeechobee. Among these are Moore Haven lock at Clewiston and the Port Mayaca lock where the St. Lucie River meets Lake Okeechobee, a waterway that links the Atlantic Ocean to the Gulf of Mexico.
Engineers at Harbor Branch designed manatee protective pressure systems more than a decade ago for canal lift gates used by the South Florida Water Management District. Last summer, the Harbor Branch manatee protection team installed the system on the Ortona Lock on the Caloosahatchee River which is part of the Okeechobee Waterway System operated by the U.S. Army Corps of Engineers. The Corps wanted a new system for lock gates that swing open too fast and sent out a public request for bids for replacement—Harbor Branch’s high frequency sound system won.
“This summer we’ll be entering into phase 2 of the second year of this important project and we will begin assisting with the installation of the devices at six locks in Lake Okeechobee,” said Larry Taylor, project manager for manatee protection systems at Harbor Branch. “We installed the prototype acoustic system about ten years ago in the St. Lucie lock. Since then, we have redesigned the system with underwater sensor cartridges. The device is now smaller, cheaper, faster and easier to operate.”
Aside from watercraft collisions, the highest incidence of human-caused mortality to manatees is due to entrapment in floodgates and canal locks. According to the Florida Fish and Wildlife Conservation Commission, locks or gates caused at least 191 manatee deaths statewide since 1974. Manatees live in shallow, calm rivers, estuaries, saltwater bays, canals, and coastal areas. They move from fresh to salt water easily and the Florida manatee frequents most areas of Florida. It is estimated that there are approximately 3,000 Florida manatees in existence today.
Adapted from materials provided by Florida Atlantic University.

Acoustic Phenomena Explain Why Boats And Animals Collide

Researchers at Florida Atlantic University have laid the groundwork for a sensory explanation for why manatees and other animals are hit repeatedly by boats. Last year, 73 manatees were killed by boats in Florida’s bays and inland waterways. Marine authorities have responded to deaths from boat collisions by imposing low speed limits on boats.

In spite of manatee protection policies that have been in effect for nearly two decades to slow down boats passing through manatee-protection habitats, the number of injuries and deaths associated with collisions has increased and reached record highs.
In an effort to reduce manatee deaths and injuries from boats, Dr. Edmund Gerstein, director of marine mammal research and behavior in FAU’s Charles E. Schmidt College of Science, set out in 1991 to investigate what might be the underlying cause for these collisions. Gerstein disagreed with the unsubstantiated assumptions, which wildlife officials had relied upon, that manatees could hear boats, but they were just too slow and could not learn to avoid boats.
“Manatees have the cognitive prowess to learn and remember as well as dolphins and killer whales,” said Gerstein. “Furthermore, when startled or frightened, manatees explode with a burst of power and can reach swimming speeds of up to 6.4 meters per second in an instant.”
Given that manatees have the cognitive ability to recognize danger and the physical prowess to evade boats, Gerstein sought to explore the answers to some simple questions. “After a manatee has been hit more than once (some have been hit up to 50 different times) why doesn't the animal learn to get out of the way?” “Is it possible that manatees are not aware or cannot hear the sounds of an approaching boat?"
Gerstein and his colleagues conducted rigorous, controlled underwater psychoacoustic (audiometric) studies to understand what sounds manatees can hear in their environment. After a comprehensive series of hearing studies, his research revealed that manatees cannot hear the dominant low frequency sounds of boats and that those sounds do not transmit well in shallow water. Furthermore, ambient noise in manatee habitats can conceivably mask the perception of many kinds of signals. Unlike dolphins, which can use active sonar to navigate and detect objects in the environment, manatees are passive listeners restricted to listening to their auditory landscape.
"It is ironic that slow speed zones result in quieter and lower frequency sounds which manatees can’t hear or locate in Florida’s murky waters,” said Gerstein. “Slow speed zones make sense in clear water where the boater and the manatee can see each other and therefore actively avoid encounters. However, in turbid waters where there is no visibility, slow speeds actually exacerbate the risks of collisions by making these boats inaudible to manatees and increasing the time it takes for a boat to now travel through manatee habitats thereby increasing the risk and opportunities for collisions to occur.”
With these issues in mind, Gerstein and his colleagues developed an acoustic alerting device specifically tailored to exploit the manatees’ hearing ability. The environmentally friendly device is narrowly focused in front of the boat so that only manatees in its direct path are alerted.
“The alarm emits a high-frequency signal which isn’t loud, doesn’t scare or harm manatees and doesn’t disturb the marine environment,” said Gerstein.
Gerstein has been testing this alarm in a NASA wildlife refuge where controlled studies are possible. He has reported that 100 percent of the controlled approaches toward manatees by a boat with the alarm have resulted in the manatees avoiding the boat up to 30 yards away. Without this alarm, only three percent of the manatees approached by the same boat moved to avoid the boat.
Manatees aren’t the only animals that collide with boats. Other passive-listening marine mammals, including great whales, are vulnerable to collisions when near the surface, where the risk of collisions with ships and boats is greatest or in shallow water. Gerstein and his colleagues are using the findings from their studies to help understand and reduce collisions in the open seas where great whales are regularly injured and often killed by large ships.
Adapted from materials provided by Florida Atlantic University.

Microbial Stowaways: Are Ships Spreading Disease?

Ships are inadvertently carrying trillions of stowaways in the water held in their ballast tanks. When the water is pumped out, invasive species could be released into new environments. Disease-causing microbes could also be released, posing a risk to public health, according to an article in the May issue of Microbiology Today.

"There is no romantic adventure or skullduggery at work here," said Professor Fred Dobbs from Old Dominion University, Virginia. Ships pump water in and out of ballast tanks to adjust the waterline and compensate for cargo loading, making the ship run as efficiently as possible. These tanks can hold thousands of tonnes of water. "Any organisms in the water are likely to be released when it is next pumped out."
Many non-native animals and plants have been taken to new environments and become invasive, threatening the survival of local species; some fundamentally alter the ecosystem. Zebra mussels were introduced in North America and the comb jelly in the Black Sea and both have had enormous ecological and economic impacts
For more than 20 years we have known that a variety of large phytoplankton and protozoa are transported in this way, but we know very little about smaller microbes like bacteria and viruses. "It is inevitable that hundreds of trillions of micro-organisms enter a single ship's ballast tank during normal operations," said Professor Dobbs. The majority of these microbes are harmless, but some are a potential risk to public health.
"Vibrio cholerae, which causes cholera in humans, can be carried in ballast tanks," said Professor Dobbs. "There have been no known outbreaks of disease associated with ballasting activities, but the water is only sampled very rarely." Other disease-causing microbes in the tanks include Cryptosporidium parvum and Giardia duodenalis, which cause stomach upsets.
Some people say microbes are present everywhere; they may be easily dispersed because they are so small. However, many experts believe micro-organisms have a "biogeography", a natural home, which means they could become invasive if moved and have a negative effect on different environments. There is some evidence for this argument: two phytoplankton species called diatoms were introduced to the English Channel from the North Pacific Ocean.
The International Maritime Organisation, which sets rules and standards for the global shipping industry, has proposed an upper limit to the numbers of Vibrio cholerae, E. coli, and intestinal enterococci contained in discharged ballast water. A few ships are also using different treatments to reduce and even eliminate the microbes in their ballast water. "A number of techniques are being looked at for this purpose, from filtration to biocides, ultrasound to ultraviolet irradiation," said Professor Dobbs. "Our understanding of the issues involved will increase as more studies are carried out, particularly those employing the tools of modern molecular biology."
Adapted from materials provided by Society for General Microbiology, via EurekAlert!, a service of AAAS.