Plant and Animal Invaders

Plant and Animal Invaders
by Krista Bergesen

The year 2010 marked the beginning of the UN’s International Year of Biodiversity in response to the present planet’s extinction crisis. But after a while, a person could start to wonder: what are some of the driving forces behind the loss of biodiversity on the planet? Well, there’s fossil fuel burning and deforestation to name a couple. That isn’t the end of the story, however.

Humans may have messed around with the ecological system even more than you may think. The increase in travel and importation going along with a global economy has allowed the transportation of many non-native plants and animals to sensitive habitats.

And that is just the beginning. These invasive species consume the resources of the original flora and fauna in the system. According to the International Union for Conservation of Nature, 40% of species are recorded as extinct because the effects of invasive species.

This has even caused economic damage. Yearly, 1.4 trillion dollars are spent worldwide on control measures and habitat restoration because of the havoc wreaked on the environment. The US itself suffers a loss of 138 billion dollars a year just for its own issues with invasive species.

As already stated, the unattended and unmanaged environment containing invasive species can result in extinction of native species. What’s worse is that the changing global temperatures are enabling non native species to gain a stronger foothold in their new environments.

For example, British Columbian forests are being plagued by mountain pine beetles, whose population has invaded and subsequently increased in number due to the milder winter temperatures. Normally, these creatures would not survive in such a harsh climate, but with the increasing global temperatures they can move further north with increasing speed in destructive numbers. Predictions have estimated that this beetle will be responsible for the devastation of 80% of pine in the province by the year of 2015.

Eradication and control efforts are commonly made against invasive species. However, in areas with multiple introduced species, it can become very difficult to foresee the consequences of various control efforts. Eradicating one invasive species may actually lead to increased damage from another.

The New Zealand ecosystem, only recently populated by humans, has faced many difficulties because of human-introduced species. Their many “management responses” dealing with the threats of invasive plants and animals have often had unforeseen consequences. Livestock, brought by human colonists has limited the habitat of Whitaker’s skink. However, when livestock was removed from certain areas to restore skink populations, predators moved in only to further reduce the skink numbers.

Despite difficulties faced in ecological restorative efforts, they are exceedingly important in maintaining diversity. To be successful, the control projects must be “intensive” and continued for long periods of time, otherwise any progress made with restoration will be lost. Also, when considering a project, all possible outcomes must be considered to ensure that more negative effects on the system are not accidently created.

It should be noted that many successful control efforts in have been documented, and that native species is preservation can be achieved. As global temperatures rise, these efforts will be more and more essential to preserving biodiversity and help slow the accelerating rates of extinction worldwide.

Berger, Matthew. “Invasive Species Threaten US Biodiversity” Guardian Environment Network. <>
5 Jan 2010.

Strong, Donald and Robert Pemberton. “Biological Control of Invading Species–Risk and Reform.” Science Magazine. Vol. 288: 1969-1970. 16 Jun 2000.

Norton, David. “Species Invasions and the Limits to Restoration: Learning from the New Zealand Experience.” Science Magazine. Vol. 325: 569-571. 31 Jul 2009.


Leave a comment

Filed under Biology, Ecology, Genetics, Policy

In the Middle of a Mass Extinction

by Krista Bergesen

The phrase “mass extinction” can conjure some scary images. Maybe one person imagines a giant meteorite hitting the earth and killing all of the dinosaurs, while another person may think of the last article they read about the human impact on the environment. Either way, it doesn’t sound like a very upbeat topic.

But what is mass extinction anyway? For one, it encompasses much more than what many of us can fathom. It usually means that at least 75% of the species globally have or are dying out on the planet. The planet would never have the same species again, and it would take around 10 million years to regenerate the same species diversity that had once existed.

It may not surprise a lot of people to know that we are in the midst of the largest extinction since that of the dinosaurs. Magazines, television ads, and even movies have tried to spread the word. Some of the messages are depressing, some are inspirational. Either way, the message is clear: the extinction is happening and humans are a major cause.

In a recent study done on the mammals in North America and their extinction rate, a group of scientists concluded that with the migration of humans to the North American continent the “normal” species’ richness declined 15-42%. Going by the definition of a mass extinction said earlier, North American mammals are already one fifth to one half of the way there. And this was before the effects of industrialization.

The anthropogenic time period, or era in which humans have existed is referred to as the “Holocene Period.” When compared with fossil samples from preceding periods, it was concluded that the beginning of the dominance of humans on the North American continent is concurrent with the decline of mammalian diversity. There has been an extinction of nine subspecies and a significant loss of habitat for other North American mammals because of the predominance of humans on the landscape.  Also, the growth of human biomass has matched the decline of the biomass of other species. Thus, the diversity of mammals, as well as the diversity of other animals is being greatly threatened by human development.

Although the study done on North American mammals is by no means representative of the whole world, it does establish one important fact. It quantifies the extinction of a certain type of animal that stands for an important part of the animal population.

In 2006, an estimate was put out by the World Conservation Union stating that 844 species had gone extinct in the past 500 years, attributing the causes to “habitat change, over-exploitation, the introduction of invasive species, nutrient loading, and climate change.” Techniques used for agriculture homogenize the plant life, and often can rid animals of their habitat or food sources. And none of these problems have shown any sign of slowing.

So what can be done? It’s pretty obvious that things have not been going well for other species on the planet with the rapid growth of the human population. For one, awareness, along with conscious action will be very important. Reserves for the natural environment need to be maintained and added to, as well as a development of sustainable energy and food production practices. Sounds difficult, and maybe impossible at this point. But the point is that something needs to be done now or the planet will face a loss of many diverse and important creatures.


Reuters. “Humans spur worst extinctions since dinosaurs.” ABC News Online.< >. 21 March 2006.

Carrasco, Mark, et al. “Quantifying the Extent of North American Mammal Extinction Relative to the Pre-Anthropogenic Baseline”. PloS one. 2009. Volume 4; Issue 12. 8331.

Barnosky, Anthony. “Megafauna biomass tradeoff as a driver of Quaternary and future extinctions.” The National Academy of Sciences of the USA. 2008. Volume 105. 11543-11548.

Leave a comment

Filed under Biology, Ecology, Policy

Tryone Hayes and the global decline of amphibians

By: Justin Scioli

Dr. Tyrone Hayes is the kind of guy that is impossible to not admire. While growing up, a young Hayes spent his free time chasing frogs, his greatest passion, through the swamps and woodlands of his native South Carolina. He took his passion in Herpetology, the study of amphibians and reptiles, all the way to Harvard University to receive his undergraduate biology degree and to UC Berkeley to receive his doctorate and later to join the faculty. But the most admirable thing about Hayes is that he is a hard-nosed scientist, keeping his data unbiased even when the results are ugly truths that many people don’t want to face. And some of Hayes’ findings are quite ugly, especially to some powerful chemical corporations.

Hayes has been primarily studying the effects of chemicals, specifically pesticides, on development of amphibians. Many of his studies examine the effects of Atrazine, the most commonly used herbicide in the United States and one of the most common in the entire world. Atrazine is used to kill weeds in crops, however like all chemical pesticides it is easily spread through runoff. This runoff carries the potent pesticide into nearby rivers, lakes, and other bodies of water where it affects the flora and fauna there.

In 2002, Hayes published a study that examined the effects of Atrazine on the sexual development of African clawed frogs (Xenopus laevis) which have been introduced in North America. The results showed that even a very small amount of Atrazine was capable of causing a tenfold decrease in testosterone levels in male frogs, making them into hermaphrodites. Hayes believes this is because Atrazine induces Aromatase which promotes the conversion of testosterone into estrogen. This basically means reducing the stuff that makes boys into boys. Of course this has detrimental effects on the sex ratio of frog populations, and Hayes believes the use of pesticides could be a major factor in a worldwide decline in amphibian populations.

Since the 1980’s amphibians, like frogs and salamanders, have been declining severely. The rate of extinction in this group is 211 times the background extinction rate, meaning that they are going extinct 211 times more frequently than rate of natural extinction recorded due to geological and ecological changes in the environment. Many causes are believed to contribute to this massive decline. In addition to pesticides, culprits such as sound pollution that interferes with vocal communication, the spread of a fatal fungus, as well as climate change and habitat destruction that is affecting nearly all life on earth. The loss of an entire class of animals would spell serious damage to food webs from the tropics to temperate regions, and some ecosystems are dependent on amphibians as an entire trophic level of organisms. What Hayes and other biologists are extrapolating from the amphibian decline is even closer to home for us.

Amphibians are a very sensitive group, largely because they absorb water through their skin. This makes them an ideal “canary in the coalmine” for seeing the levels of chemical toxicity due to pollution in a given environment in which they are naturally occurring. When amphibians are dying, that is a good sign that toxicity levels are increasing. More and more studies are showing the detrimental effects of pesticide exposure on human health. In a talk given in 2008, Hayes discussed that levels of toxicity are shown to be lower in breastfeeding women. This is due to the fact that they are excreting toxin through their breast milk and thereby transferring it to their child. Frog or human, developmental stages of life are much more sensitive to toxic pesticides than adults. This spells compromised immune systems for the young and developing, and the fact that Atrazine is the most common contaminant in ground, surface and drinking water is concerning for many.

The European Union banned the use of Atrazine in 2004. The United States on the other hand continues not just to use it in agriculture but to allow a given concentration of it in drinking water. Recent studies show that the allowed amount of Atrazine can lead to low birth rates, birth defects and menstrual problems. Despite this, the EPA continues to suggest that there is no need for concern and is not officially suggesting water filters to pregnant mothers. They will not review those studies until next year at the earliest, and in the meantime pregnant women throughout the U.S. could be sipping up Atrazine any time they drink from a tap.

Leave a comment

Filed under Biology, Chemistry, Ecology

Sagittarius A*: Our Galactic Neighbor

By: Josiah Houck

Ever heard of Sagittarius A*? It’s kind of a big deal. It weighs as much as 4.5 million of our suns put together, and it has a diameter of 44 million kilometers. It is, as some would say, supermassive. And it’s relatively close to earth. So how come you’ve never heard of it? (or, if you have heard of it, how come you don’t think about it more often?)

Sgr A* (as it is lovingly known by astronomers and astrophysicists) is the name of the Milky Way Galaxy’s hub. It is the gravitational center around which the spiral arms of our galaxy spin, and without it our solar system would be either flying through space, confused and directionless, without a place to call home, or, we’d be stuck in some other galaxy knowing there was something better out there.

Our relationship with Sgr A* is a complex one. Albert Einstein was one of the first to discover just how intertwined our lives are with this gravitationally immense neighbor.  He showed in his theory of relativity that gravity actually impacts the “flow” of time, and that areas of the universe like Sgr A* actually warp time with their attractive forces.

Theoretical physicists (like Einstein, Stephen Hawking, and Sheldon from Big Bang Theory) have surmised that in order to satisfy their extensive calculations, areas such as this must exist. The term that has become popular to describe them is “black hole.” Essentially, a black hole is an area through which material can only flow one way. “Material” in this case refers to “spacetime,” which is a convenient way of grouping time and space together in equations, making them a singular unit composed of four dimensions (the fourth being time).

General relativity predicts that black holes exist because gravity arises from the curvature of space. Without getting into the intricacies of the mathematics involved in the claim, suffice it to say these black holes are the cause of these spatial curvatures, bending spacetime with their gravitational pulls.

There are two main groupings of black holes: stellar-mass, and supermassive. The first is created from the remnants of a massive star that has collapsed. A star more than eight times as large as our sun (or much larger) collapses in on itself and creates a supernova explosion or gamma ray burst.

It is not known exactly how or when supermassive black holes form, though there are several theories, but it is known that they are massive in the literal sense, ranging from hundreds of thousands to billions of solar masses large. Interestingly though, all black holes are hyper-condensed, so even one that had a solar mass of one billion would fit within the orbit of Neptune (Broderick and Abraham, Scientific American, 2009).

Sgr A* is nowhere near that big, but it still qualifies as supermassive, as well as super relevant. It is only 24,000 light years away, which seems like an insane distance to preface with “only.” BUT, when you consider that the entire Milky Way Galaxy is 100,000 light years across, that means that we are relatively close compared to the rest of our galaxy. To further put it into perspective, the next-closest supermassive black hole that astrophysicists have found suitable for study is 55 million light years away. So, I maintain that it is a close neighbor.

If you think of the galaxy as a community, the Milky Way Manor, or something along those lines, Sagittarius A* is the rich, powerful resident with a lot of sway about town. All the stars revolve around it, and are subject to its daily whims. Luckily, it is consistent and non-volaitaile. For now, it seems content to keep the arms of the Milky Way spinning, while occasionally devouring an unlucky photon or gaseous particle that goes to close to its event horizon. Let’s hope it stays that way, lest it become an annoying (or deadly) neighbor. For now, this is the only neighborhood we can afford to live in.

Leave a comment

Filed under Physics

Chlorine in Your Bleach?

By: Lizzie Caldwell

Through consistent pressuring from environmental watchdogs such as Greenpeace, Clorox has made plans to stop using chlorine in their bleach. This could be a good thing and a bad thing. Think of a swimming pool. Chlorine is extremely reactive, which makes it a really effective chemical to use against bacteria and other organic waste that can make us sick.  This is why we chlorinate pools every day. However, because chlorine is extremely reactive, it can be dangerous to our bodies and to the environment when it gets thrown into the ocean. This is why we are told not to swim in pools shortly after chlorine is thrown in. After a few hours, chlorine reacts with organic molecules that come from everyone’s mouths, feet, hair and skin to produce neutralized compounds that will not make us sick, and we can swim in the pools again. For the same reasons, chlorine in laundry detergent is good because it gets rid of those food and grass stains, but bad because it can be potentially harmful to us and the surrounding environment (after the waste with chlorine gets dumped into oceans).
Chlorine is strongly electronegative, which is what makes it reactive. Electronegativity is when an atom doesn’t have enough (or has too many) electrons to make it stable. If you look at the periodic table of elements, you can see the row of helium, neon, and argon is the last row on the right. These elements aren’t reactive because their “outer shell of electrons” are completely filled. Each outer shell, except for hydrogen and helium, has space for 8 electrons. The element directly before or directly after this last row has 1 too many electrons for stability or 1 too few electrons for stability.

Being so close to a stable state makes the element VERY eager to gain an electron or give away an electron. Chlorine in particular is very eager to gain an electron, and becomes attracted to other elements that are very eager to lose an electron. This trend holds true for any element in row 1 and 17. Row 18 is for the most stable elements, which is where neon and argon lie.

Chlorine is particularly bad for oceans because of this reactivity. When chlorine comes into contact with water (which consists of 2 hydrogen atoms attached to an oxygen atom, thus H20), chlorine rips apart the bonds between those elements and can turn into various acids: hydrochloric acid (HCl), chloric acid (HClO3), perchloric acid (HClO4) and more. When we wash our clothes and our laundry detergent goes down the drains into the ocean, we are literally making the ocean more acidic.

Whether your background in chemistry is strong or weak, many people know that acid is bad! Luckily, the acid isn’t strong enough to harm humans, but fish and plants that live in the ocean are much more sensitive to the acid. Increasing the acidity of the ocean literally deteriorates ocean organisms. This is good for our swimming pools since we don’t want our swimming pools full of animals and wildlife – but do we want our oceans looking like our swimming pools? Lifeless and sterile? Where would our sushi and our crab cakes come from? Who would want to scuba dive anymore?

Of course, there is another portion to every argument. In this case people are concerned about how effective bleach without chlorine can be at removing stains we don’t want. One company, BleachTech, can make bleach directly from salt without isolating chlorine (table salt is made up of sodium molecules and chlorine molecules). Since the House of Representatives passed H.R. 2868, which requires high-risk chemical plants and water-treatment facilities to use safer processes or chemicals, other bleach and laundry detergent companies will follow suit to find safer and more eco-friendly alternatives instead of chlorine. Clorox has also made a statement that the new bleach will not be different in color, smell or quality. Thus, Clorox’s decision to remove chlorine from their bleach is a very good thing because it will prevent the environment from suffering further damage, while the quality is not compromised.

Leave a comment

Filed under Chemistry, Policy

Ghost Fishing

By: Kimmie Riskas

Before the widespread use of synthetics in the 1950s, all fishing gear was made from natural fibers, typically hemp and cotton, and strengthened with a coating of tar or strips of canvas. If lost or discarded at sea, the natural fibers would quickly lose buoyancy, disintegrate, and be chewed into nothingness by marine microbes.

Plastics, however, are durable, lightweight, and cheap, which is why synthetics have almost entirely replaced natural fibers in fishing gear over the last 35 years. Synthetic gear doesn’t break down as readily under prolonged submersion and UV light bombardment as hemp does. Decomposition by algae and colonial invertebrates happens more slowly on synthetic gear, if at all. It’s cheaply mass-produced. If broken or mislaid, synthetic gear is readily dumped overboard, left to drift through the oceans intact. There’s evidence that plastics may last even longer in the ocean, where salinity, temperature, and varying periods of exposure to direct sunlight prolong the plastics’ life far past that of plastic abandoned on terra firma.

All these long-lasting ropes, nets, and lines in the ocean carry unintended consequences for the creatures unfortunate enough to come across them. It’s called ghost fishing, and it’s responsible for the deaths of thousands of seabirds, whales and dolphins, sea turtles, marine mammals, fish and crustaceans every year. Discarded nets and lines quickly accumulate growths of marine algae and fouling colonies of invertebrates (barnacles, crabs, anemones, worms, and the like). Fish predators attracted by this floating buffet meet their death by entanglement. The gear accrues such masses of algae, debris, and dead animals that it sinks under the weight, hovering under the surface at anywhere from twenty to two hundred meters. Once some of this organic load rots away, the ghost nets rise vertically in the water column via buoyant plastic floats, to ensnare more wildlife and being the cycle over again.

A 1997 study by D.W. Laist in the Marine Pollution Bulletin by found that marine debris harms more than 267 species worldwide, including 86% of all sea turtle species, 44% of all seabird species, and 43% of all marine mammal species. In 2000, a single, derelict net recovered in Alaskan waters contained 350 dead seabirds and hundreds of rotting salmon. Sea turtles often mistake floating plastic bags for the diaphanous jellyfish that make up the bulk of turtles’ diets; hundreds of whales and dolphins wash ashore annually whose stomachs and respiratory tracts are choked with plastic sheeting and packaging material. Ghost nets are also destroying coral reef communities, snagging and breaking the very structure of the reef as the nets are dragged along by currents.

In 1975, having completed the transition to synthetic fishing equipment, international fisheries collectively dumped 135,400 tons of plastic gear into the world’s oceans. Although it’s difficult to measure exactly how much of it is floating in the ocean today, expansion of international fisheries and shipping industries since 1975 suggests that the amount of jettisoned fishing paraphernalia has significantly increased as well. The dumping of plastic trash and fishing gear from ships at sea has been banned since 1990 by international shipping regulation MARPOL Annex V. While there is some indication that the amount of discarded flotsam and jetsam has declined slightly in well monitored areas since the ban’s implementation, the vast majority of the world’s oceans are unpatrolled and regulations remain unenforced. An estimated 6.5 million tons of plastic debris are still dumped overboard every year.

Despite the damage caused by ghost fishing in the world’s oceans, discarded fishing gear accounts for a small percentage of marine debris. Litter composition varies by area, reflecting local use of containers, packaging, and fishing equipment. For example, in the eastern China Sea, where fishing is the dominant economic activity, 72% of marine debris originates as nets, ropes, and buoys discarded from fishing vessels. In Jakarta Bay, Indonesia, 42% of marine debris is polythene plastic bags; fishing here has been curtailed as increasing discharge of sewage and industrial effluent from the nearby city poison the water and make commercial fishing unprofitable.

Leave a comment

Filed under Biology, Ecology, Policy

The Fight Against Neglected Diseases – Part I

Join Elena Coupal as she investigates the world of neglected diseases, medical research, orphan drugs and the pharmaceutical industry in a multi-part series: The Fight Against Neglected Diseases.

Part I: Private-Public Partnerships

Imagine your body racked with fever and chills, shaking uncontrollably from coughs that bring up anemic blood. The parasite Plasmodium falciparum has all but destroyed your red blood cells. Your parents, both long dead from AIDS, cannot help you. A sibling quickly rushes you to the village doctor, only to be given a grim prognosis: Malaria and tuberculosis. We do not have the medicine. Sorry; we can’t help you.

In a few days your body, overcome with disease, will give up the fight. You have now become a statistic, one of millions of children who die every year from treatable, preventable diseases. These diseases, which have been all but eradicated by vaccines and treatment in industrialized nations, include malaria, tuberculosis, dengue fever, and a host of other tropical diseases.

These tropical diseases thrive in the climates south of the Sahara and in Southeast Asia, which also include some of the most poverty-stricken regions in the world. This staggering loss of life occurs predominantly among the most at-risk groups: pregnant women, whose immunity is lowered by their pregnancy; young children, whose bodies haven’t yet developed any immunity; and migrants, who are susceptible to foreign diseases they have no immunity against. The mortality statistics seem almost unreal amidst the glitz and glamour of the modern science we enjoy today.

After all, if we can find treatments for cancer and develop drugs that alleviate the effects of Alzheimer’s and Parkinson’s, then what’s stopping us from removing diseases such as malaria and tuberculosis from the list of major world-wide problems? The answers all boil down to the main issue of cost.

According to the Drugs for Neglected Diseases Initiative (or DNDi):

Tropical diseases and tuberculosis account for 11.4% of the global disease burden

1,556 new drugs were approved between 1975 and 2004

However, only 21 (1.3%) were specifically developed for tropical diseases and tuberculosis

Because of the extreme poverty in regions where these diseases are endemic, there is no local capital available for disease control or for the research and development of new drugs. The process of producing and distributing drugs is extremely expensive. It can cost anywhere from $400 million to $800 million to cover research and development, clinical trials, registration, manufacturing, and distribution of a new medicine.

Since the people who need these drugs the most cannot afford to pay for them, any pharmaceutical companies and organizations that provide these medicines to poorer regions do not see one cent of profit. This fact is especially problematic for big pharma companies that have obligations to their profit-seeking shareholders.

However, the arrival of public-private partnerships, or PPPs, has resulted in a multitude of benefits for all. Top scientific experts from academia and industry teaming up with non-profits and philanthropy groups provide a vast new pool of resources from which drugs can be developed and disturbed to those most in need.

Such partnerships include the Novartis Institute for Tropical Diseases (NITD), Johnson & Johnson with the TB Alliance, Merck with Wellcome Trust to form MSD Wellcome Trust Hilleman Laboratories, and the PATH Malaria Vaccine Initiative (MVI) which was formed from donations from the Bill & Melinda Gates Foundation, just to name a few.

The corporate, for-profit organizations provide the latest technology and techniques, as well as extensive libraries of “starter molecules” for making drugs. They also provide professional advice about which projects would be best for non-profits to pursue.

Nonprofits have access to funds that do not require a return of capital. Nonprofits also have the freedom to focus on “the bigger picture,” and can gather a variety of results from the most recent clinical breakthroughs to assist and direct the process of drug discovery in the private sector. Also, partnering with a non-profit can be great PR for private corporations.

Although relatively new on the scene, PPPs have already shown early success. For instance, according to a 2005 London School of Economics report sponsored by Wellcome Trust, from 2000 to 2004 PPPs developed 46 new drug projects with only $112 million dollars, an astonishingly low number in comparison to what big pharmaceutical companies will usually spend on a similar number of projects (see the $800 million statistic above).

PPPs have a promising future, and with further collaborative efforts, will continue to succeed.

So far, PPPs have proven to be our best ally against these neglected diseases that cripple entire populations and hinder development and education efforts in unindustrialized nations. With help, support, and collaboration amongst many private, public, and philanthropic organizations, it has become more possible than ever to bring these neglected illnesses out of the shadows, so they can be conquered and eradicated.

But first you must get to know your opponents before you can fight them.

Come back for more on neglected diseases in the next few weeks!

1 Comment

Filed under Biology, Health