January 2005

Have you noticed that nearly everyday in the newspaper or on the television we hear more about global warming? A series of typhoons and storms have recently caused severe flooding and loss of life in the Philippines. Is this a global warming signal? Scientists are not sure. Most scientists agree global warming is real; how can they deny the data, the melting glaciers and warming oceans? And most scientists believe global warming is intensified by humans producing greenhouse gasses such as carbon dioxide.

According to a new paper in Nature, a British research team has determined, using powerful mathematical models and super computers, the increased greenhouse gasses have more than doubled the risk of record breaking hot European summers. In 2003 more than 27,000 excess deaths occurred across the continent, and the summer temperatures of 2003 were the highest in Europe in the last 500 years. This graph presents one of the more pessimistic possible scenarios forecast for temperatures in Europe over the next century. The temperatures observed in the summer of 2003 are noted by a star. According to this forecast, last year's highs could be the starting point for much warmer temperatures to come. (Credit: Peter A. Stott, D.A. Stone & M.R. Allen/Nature/NPR). You can learn more about global warming and greenhouse gasses in the article below written by CSI Fellow Meghna Tare.

But greenhouse gasses are not the only pollutant humans are dumping into the environment. One of the most common pollutants is petroleum products, and a new book enlightens us to the toxicity of these compounds. Sound Truth and Corporate Myths, by Dr. Riki Ott (Dragonfly Sisters Press) focuses on the findings from the Exxon Valdez oil spill experience. It's really two books in one with one section dedicated to understanding the effects of oil and chemicals used during the cleanup on oil spill workers, while the other section describes the effects on fish, birds, mammals, invertebrates and their habitat.

After the Exxon Valdez spilled oil into the pristine waters of Prince William Sound a small army was deployed to clean up the mess. One of techniques for washing the oil off the beach rocks was to blast the beaches with high pressure seawater heated to 160 degrees. The spray created a toxic cloud of oil mist and oil aerosols that enveloped the workers, made many sick, and may have caused permanent damage to thousands of workers. Dr. Ott diligently reviewed Exxon's air quality monitoring data, Exxon's clinical data, and medical records in personal injury lawsuits filed by sick workers, and medical texts and other reports about the effects of inhalation of oil droplets by people. She compared this to what she learned from interviewing the spill workers. She uncovered what Exxon doesn't want anyone to know: that inhalation of petroleum compounds can cause permanent damage to people; and that long-term consequences include reproductive and developmental damage, central nervous system damage and cancer, and can include damage to a person's chromosomes.

When cleaning the beaches proved to be difficult to impossible, Exxon began to use chemical cleanup products, dispersants and other chemicals, which were sprayed on the oiled beaches by workers without adequate protection. Many of the test products, including Corexit 9527, Inipol EAP 22, and simple green, contain 2-butoxyethanol, a chemical listed by U.S. OSHA as a human health hazard and which the U.S. EPA describes as posing very high risks to people and the environment, and capable of causing reproductive and fetal damage, and liver, kidney, and blood damage.

Workers described their symptoms as dizziness, nausea, depression, difficulty breathing, and severe headaches, among others. These can all be symptoms of chemical poisoning. Through manipulation of the legal system, most of the chemical exposure cases against Exxon we thrown out of court or settled for the minimum of $10,000. According to Dr. Ott's investigation, environmental medicine doctors recognize that anyone who comes into contact with any of these chemicals, including low levels of airborne oil from burning of fossil fuels and household products that contain 2-butoxyethanol, is at risk of building up these chemicals in their bodies to a level that may harm health.

The high pressure heated seawater treatment used to clean the beaches also had dire consequences for habitat and wildlife. The government research findings conclude that this cleanup technique washed the sand and mud away so infauna, animals that live in sand and mud, had no place to live. They perished and their recovery was impossible without their sediment habitat. Dr. Ott systematically describes these and the government's other damage assessment research findings as well as the Exxon-hired scientists' findings. She exposes the abuses of statistics and the scientific process Exxon scientists used in an attempt to discredit any research findings that found the oil spill and cleanup caused harm, especially long-term harm.

But if there is such a thing as a perfect place to spill oil to study long-term effects, it is Prince William Sound which was relatively pristine and where the federal government had baseline data on background oil levels. The oft-used defense by oil polluters is that their pollution was not significant because of the pre-existing pollution. But this was not the case in Alaska; Sound Truth and Corporate Myth$ presents the irrefutable scientific evidence that oil causes long-term harm to wildlife.

But this has not changed the strategies of the oil companies to continue pressing to open up new areas for oil development and to use chemical products to clean up oil spills, so I recommend you read Sound Truth and Corporate Myth$ so you can learn how to respond to the industry's 'tobacco science.'

The book also examines the three ecosystem projects funded to help understand the affects of the oil spill in broader terms and other (natural) factors affecting the North Pacific Ocean ecosystem. The ecosystem project, Alaska Predator Ecosystem Experiment or APEX, investigated the issue of declines of some marine bird and mammal species prior to the oil spill in a way that put the spill into perspective (see http://www.conservationinstitute.org/apex.htm). Sound Truth and Corporate Myth$ does a good job of summarizing the APEX project and the two other ecosystem projects. (see also http://www.soundtruth.info/index.htm)

Many of the CSI staff and fellows have worked for the programs to study the effects to and restoration of the Exxon Valdez oil spill region. Anne Salomon is investigating the community structure, dynamics, and diversity of the region's rocky intertidal zone. Drs. Okey and Purcell have also worked in Prince William Sound. You can read more about oil spills and oil pollution at http://www.conservationinstitute.org/oilpollution.htm.

Many tools for large scale conservation planning have been set forth in terrestrial systems, but they have not yet been applied widely in marine systems. Only a few marine reserves have been established, and these are usually intended to protect species valuable to eco-tourism or sport fishing. Sharks have been widely overlooked in conservation planning even though they are experiencing precipitous population declines. Sharks are also becoming increasingly important commercially, both for fisheries and marine eco-tourism.

My goal is to develop a framework for bringing together information on basic biology with the needs of fishers, shoreline developers and tour operators to produce a conservation plan for a large marine vertebrate. My focus is on a species of large shark, the bull shark, Carcharhinus leucas. I will collect data on movements and migration, integrate them with what is known about the reproductive biology of other populations and develop an action plan for conservation that can serve as a model for others involved in marine conservation.

The Bull Shark Tagging Programme is currently in its second stage. We equipped six mature bull sharks in 2003 with state-of-the-art pop-up satellite tags at Walker's Cay, Bahamas. The reason for this pre-study was to develop a new tag attaching technique and to gain a first insight into bull shark migration behaviour. The results of this study are submitted to a journal for publication early next year.

The main study takes place around Fiji in the South Pacific. Between January and October bull sharks gather around a reef near Beqa Lagoon off the southern coast of Viti Levu. The exact size of the population is not yet known but many of the sharks are easily recognizable from external features such as color patterns or scars. Like the bull sharks from the northern hemisphere, these animals leave the area in late spring and return in late summer. But so far, nobody knows exactly where they go. When they return however, they are often seen with mating scars and without the massive belly the pregnant females display before their departure in springtime. There are plenty of questions we as researchers need answers to and with the satellite tagging effort we had started on the first step into a long and fascinating journey that could only lead to a profound insight into bull shark behavior and ecology.

When we tagged the bull sharks in the Bahamas in 2003 we used a fiberglass tag stick while working from a wooden platform which extended over the water. This allowed easy access to the sharks without getting wet. This time however, due to the 30 meter working depth of the resident population of sharks in Fiji we had to tag the bull sharks while free swimming with them.

For the first few days of diving we allowed the bull sharks to get used to us. We swam around the bull sharks with the tag stick to let the animals get used to our presence while carrying the device. Numerous times sharks would approach within inches to examine this curious appendage that we held while inspecting us as well. This is a typical behavioral trait that we have witnessed in bull sharks before. They seem very comfortable swimming within a few inches of a diver in a curious non- threatening manner. Of course if someone is not aware of this particular trait it is often misinterpreted as threatening or aggressive behavior that is being displayed by the shark.

By the end of the week we were ready to mount the first data collecting satellite tag. After destroying several tagging darts we learned quickly in those first tagging attempts that the skin of the bull shark is incredibly tough! However, after some tag anchor modifications we were able to place the first successful units beside the first dorsal fin in the thick fat and muscle pad of three mature bull sharks. The sharks certainly must have been amazed at the ensuing celebration underwater by all the staff when this first tagging effort was completed. And why not! We had perfected this free swimming tagging technique which minimized the trauma to the shark, unlike conventional tagging techniques which unfortunately can cause behavioral trauma and far too often a large mortality rate in its' subjects in the name of science. This technique also allowed us to specifically pick a particular individual which could yield the most abundant and significant data. And the tagged sharks could have cared less! Not one tagging effort induced a negative response in any shark. In fact all three initial subjects returned the same day to feed and interact, oblivious to the fact that they were already making scientific contributions! The units are set to pop-up to the surface at the end of the year after gathering valuable data on depth, temperature, light intensity and range of travel.

To save the dwindling shark population of our planet it will take the efforts of thoughtful and committed citizens from around the world. The collaborative effort of an eclectic group of shark specialists combined with the citizens of Fiji and their love for their waters and the fragile creatures within its realm have merged intimately with science to create a formula that other countries around the world should take note of.

Most of us learned about the hydrological cycle in the science class when we were in high school. We learned the hydrological cycle is nature's way of providing us with water, a basic necessity of life. The cycle begins with the evaporation of water from the surface of large water bodies such as oceans and lakes. The water moves into the atmosphere, where it travels until it's cooled. It then condenses and precipitates in the form of rain or snow. The snow melts during summer and finds its way back into the ocean. A warmer atmosphere may intensify this cycle. Changes in the ocean circulation or the chemical property of water can disrupt this hydrological cycle causing droughts and/or floods in various parts of the world.

The oceans contain 97% water, experiences 86% of the evaporation and 78% of the precipitation in the form of rain or snow. With the increase in the temperatures due to global warming, the rate of evaporation increases. Since evaporation concentrates salt on the surface of oceans, detectable salinity spikes are observed as temperature rises. In contrast, low salinity generally reflects the addition of fresh water to the ocean through precipitation and runoff from the continents.

Scientists have observed that surface waters in the tropical and subtropical Atlantic Ocean have became more saline and much of the water column in the high latitudes of the North and South Atlantic have become fresher. These trends indicate that fresh water has been lost from the equator and added at the poles at a pace exceeding the ocean's ability to compensate. The North Atlantic is one of the few places on earth where the salty surface water is chilled and sinks to flow south towards Antarctica. There, it is cooled further to flow outward at the bottom of the oceans into the Atlantic, Indian, and Pacific basins. After upwelling primarily in the Pacific and Indian oceans, the water returns as surface flow to the North Atlantic. This thermohaline (temperature- and salinity-controlled density) circulation of the oceans water is called the “oceanic conveyor belt”. This conveyor helps draw warm Gulf Stream waters northward in the Atlantic, pumping heat into the northern regions that significantly moderates wintertime air temperatures, especially in Europe. The water releases heat into the cold northern atmosphere at a rate of a trillion kilowatts, an amount equivalent to a hundred times the world's energy consumption. This energy warms the air over Europe by about 5 degrees C. If the North Atlantic becomes too fresh its waters would stop sinking, and the conveyor could slow down or stop.

In a paper published in 2002 in Nature, oceanographers monitoring and analyzing conditions in the North Atlantic concluded that the North Atlantic has been freshening dramatically-continuously for the past 40 years but especially in the past decade. The data showed that since the mid-1960s, the North Atlantic has steadily and noticeably become less salty to depths of 1,000 to 4,000 meters. The melting of glaciers and polar ice - another consequence of global warming, also adds fresh water to the North Atlantic. Global warming thus affects the hydrological cycle because a warmer atmosphere carries more water. This, in turn, has implications for greenhouse warming, since water vapor itself is the most abundant greenhouse gas.

The bushmeat trade represents one of the most immediate threats facing tropical vertebrates in Africa. This threat follows a pattern in which increased hunting occurs in years with low fish supply. Fish is a staple food for many western African nations and when supplies run low, people look elsewhere for other sources of available protein.

A group of researchers studying the correlation between bushmeat trade and fish supply compared the annual rate of decline of annual standing biomass of 41 mammals in six Ghana nature reserves. The study used data from a 28-year period between 1970 and 1998 to compare and correlate fish supply and terrestrial biomass change.

The study found that years with below average fish supply had above average declines in wildlife biomass. Counts in nature reserves over this period show an increase in the number of hunters as fish supply dropped, increasing the pressure on wildlife. Also, as fish supply dropped in local markets, and price increased, the volume of bushmeat increased to fill the void.

Ghana, like many other nations, has a large proportion of its population living near the coast. Fishing provides not only an important food source, but also employs many people and drives local economies. The dual pressure from lack of jobs and available protein increases hunting pressure and the overall bushmeat trade. Although the impact on wildlife will be most severe in those parks and reserves closest to the coast, impacts from low fish supply negatively affected wildlife in all six reserves in the study.

Biomass of the species included in this study dropped by over 75% over the 28-year period of the study. In addition to the overall loss of biomass, 16-45% of the species became locally extinct over the same time period. Fish supply numbers fared just as poorly. Human population over this period increased by three times, resulting in lower per capita fish supply overall. Exploitation and overfishing by foreign and domestic vessels led to unstable fish supply levels. Findings in this study suggest that the total collapse of either the bushmeat or fish markets would likely result in widespread famine, poverty, and social unrest.

Alternative food supplies, including agriculture and livestock, would help reduce the stress on wildlife in times of low fish supply. However, these would take years to implement and would likely face many economic and social obstacles. Effective measures aimed at protecting African terrestrial wildlife will have to include not only wildlife reserves but a fisheries management program that will ensure a consistent supply of fish to the people of Ghana and of west Africa.

The past decade has seen an unusual number of large, stand replacing fires in the western forests of the United States. They are unusual in that tree ring data from the time period 1500-1900 shows a trend of low intensity fires occurring on a frequent basis that helped to maintain open stands and preclude large stand replacing fires.

Forest fires in western ponderosa pine forests have increased in size and severity and have garnered substantial media and political attention. The US now spends over $1.5 billion annually on fire management and has adopted the Healthy Forest Restoration Act (HFRA) in an effort to curb fires. Many people believe that decades of fire suppression have created this current crisis. The HFRA prescribes thinning as the management tool to reduce fire loads, reduce catastrophic fires, and to reestablish ecological balance.

However, a group of researchers analyzing post fire related deposits, or debris flows, have proposed that fire suppression alone may not be the only culprit for the rise in catastrophic fires this century. Establishing a chronological record of erosion and debris flows over the past 8,000 years has uncovered a climactic pattern to fire history.

Using charcoal data found in these debris flows, the researchers correlated such flows with climate records. They found that colder periods were characterized by low intensity fires and small debris flows, whereas warmer periods experienced more catastrophic fires, followed by large debris flows. Cooler, wetter conditions maintain moisture in the canopy of trees and produce understory growth that lead to low intensity fires and maintenance of open stands. Warmer, drier conditions, particularly extended periods of drought, cause canopy moisture to decrease to critically low levels and increase the likelihood of catastrophic fire.

During the Medieval Climatic Anomaly (1050-650 years before present) warm temperatures led to multi-decade droughts, severe fire conditions and large debris flow events. In contrast, the Little Ice Age (from 1500-1900) produced high frequencies of low intensity burns. Current management strategies to reduce catastrophic fire, including the HFRA, use the Little Ice Age conditions as the baseline. Climate change this past century has created much drier conditions and a higher frequency of catastrophic fires that thinning will not likely be able to reduce.

Human impacts to coastal ecosystems, including overfishing, pollution, and other forms of habitat degradation, have led to visible declines in species and systems. While many species have the ability to avoid localized impacts of pollution, immobile invertebrate species living in the top layer of mud and sediment on the ocean floor, or benthic zone, do not.

Benthic invertebrates play a key role in marine ecosystems. Their movement on the ocean floor and in the soil beneath it influences bioturbation, or the biogenic mixing of ocean sediment. This mixing invigorates the system with oxygen, allowing for other species to flourish. A team of researchers have used these invertebrates to model the impact extinction of these species might have on important ecological functions.

The study looked at 139 invertebrate species from the Inner Galway Bay in Ireland and forecast how the extinction of species would impact biogenic mixing. Each species has a particular biogenic potential based on its size, abundance and several other factors. Given this potential, mathematical models were created to determine what impact the loss of any one species would have on overall biogenic mixing.

Predictions from the model indicate that the loss of species diversity impacts mixing in all extinction scenarios. The overall rate of change, however, depends on which species go extinct and when. Although the model suggests that the survival of high impact species can maintain sediment mixing for a time, a loss of species diversity overall could lead to dramatic consequences.

Their study concludes that the order of species extinction affects overall sediment mixing. The importance of this finding, they suggest, indicates that whatever contributes directly to extinctions determines the overall ecosystem consequences of biodiversity loss. Understanding which species are at risk, and for what reasons, will allow for predictions of what impacts extinction will have and for the protection of coastal ecosystems.