Climate change is triggering population booms and declines for certain types of algae in Lake Tahoe, according to a recent study from the UC Davis Tahoe Environmental Research Center.

The shifting makeup of these algae communities could affect biological and physical conditions in the lake, including the food web and water clarity.

“We saw that smaller sized species are more abundant now, but diversity did not change,” said Monika Winder, a postdoctoral researcher and lead author of the study. “That shows us that the change in size structure is really driven by something else.“

Since 1970, the average water temperature of Lake Tahoe has increased nearly one degree while the surface water temperature increased nearly two degrees, according to TERC’s State of the Lake Report 2008.

The stronger warming trend in the surface compared to deeper water has changed the mixing pattern of the lake by decreasing circulation of water between the upper and lower depths.

Single-celled algae called diatoms depend on turbulent water mixing to remain suspended in the upper depths of the lake where there is enough light for them to grow, Winder said.

“The warming leads to conditions that are making it more difficult for larger diatom species to stay afloat,” said TERC director and contributing author Geoffrey Schladow in an e-mail interview. “So instead, the smaller species that were always present but in low numbers are filling the gap and taking over.“

The researchers looked at data collected from Lake Tahoe since the early 1970s, from which they could document changes in diatom species composition and size structure, water temperature and strength of water mixing. They found that while the overall amount of diatoms did not change significantly, there was a shift toward abundance of smaller sized species and decline in larger species.

The study confirmed previous hints from fossil evidence that warmer water temperature shifts the relative distribution of diatoms in favor of smaller sized species, Winder said.

The change correlated with a trend toward weaker water mixing over the years, an effect that can be explained by simple physics. Larger diatom species sink faster in the calmer waters compared to their smaller, lighter counterparts. Meanwhile, the smaller species flourish because they can remain in the upper light-reaching water layer for longer periods of time.

The structure of smaller species also makes them more efficient in taking up nutrients, which tend to accumulate at lower depths when there is less mixing, Winder said.

The amount of nutrients in the lake remained relatively stable over the years, and changes in water clarity did not appear to drive the change in size structure, she said.

“The size change in diatoms will impact those species that consume them,” Schladow said. “These feeders include tiny animals called zooplankton, which in turn are eaten by small fish, which are eaten by larger fish and birds, and so on up the food chain.“

The researchers agree that more studies are needed to determine how the change will affect the Tahoe food web.

It could change the abundances of zooplankton that select certain size diatoms for consumption, Winder said. She has observed a decrease in one zooplankton species during the study, but whether the decline is related to the change in diatom species or some other factor is a subject of ongoing research.

The proliferation of small diatoms in the upper water layer may also have indirect consequences for the lake by affecting carbon sequestration and cycling and reducing water clarity, Winder said.

The study was published several months after an earlier TERC report announced that ongoing loss in Lake Tahoe’s water clarity has slowed since 2001.

ELAINE HSIA can be reached at campus@californiaaggie.com.

HIV affects new populations in China

While China has a low number of HIV cases – 700,000 – for a population of 1.3 billion, the rising infection rate is cause for concern, according to a study based out of Rockefeller University.

Since 2005, the number of cases has risen by 8 percent and expanded into all provinces. Transmission is increasing especially rapidly among gay men and female prostitutes.

AIDS is believed to have entered China through drug traffickers in Yunnan province during the 1980s. Yunnan borders Southeast Asia‘s opium “Golden Triangle“ and is now the province the hardest hit with the epidemic. The disease spread further in Henan where illegal blood banks sold blood collected from indigent farmers. (source: nytimes.com)

Study shows one in four mammals face extinction

Conservation scientists have made the first update to the Red List of Threatened Species in over a decade. The study concludes that one in four of the world‘s mammals is threatened with extinction and the population of one in two is declining.

Primates are particularly threatened due to major habitat loss in Southeast Asia and hunting in Africa. There are also unusually high threats to hippos, bears, pigs and hogs. Larger mammals are more threatened as they tend to grow slower and have large ranges with low population density.

Habitat loss is the major threat to land species while marine mammals are threatened most by accidental death, especially from by-catch and being hit by ships.

The report was published by the International Union for the Conservation of Nature, the world‘s oldest environmental network consisting of more than 1,000 government and nongovernmental organizations and over 11,000 volunteer scientists in 160 different countries. The research took five years and involved over 1,700 scientists from around the world. (source: Associated Press)

Science Scene is compiled by ALYSOUN BONDE. She can be reached at campus@californiaaggie.com.

UC Davis chemistry lecturer Andreas Toupadakis came to America from Greece in 1978 to get his Ph.D. in chemistry from the University of Michigan. After teaching at several universities around the country, he found a home at UCD several years ago.

Toupadakis has more holistic extracurricular interests than your average chemistry professor – including philosophy, life planning, gardening and making his own soap.

What classes do you teach? Do you have a favorite?

For four years now I have been teaching General Chemistry, the 2ABC series, for freshman students majoring in the life sciences. I also teach Physical Chemistry for Life Sciences, the 107AB series, mainly for fourth year students. This year I am also teaching Chemistry 10 for the first time, which is for students majoring in something other than science.

I do not think I can say I have a favorite. Each level of these classes satisfies a different part of me.

Do you have a specific lecture style?

I definitely have a certain lecture style. I emphasize conceptual understanding rather than mechanical memorization. To that end, I try to attract the type of students to join my classes who are willing to do the “chemistry walk” in order to understand the mystery of our universe and feel the joy that results from such understanding and appreciation. I encourage the students who join my classes to participate in a Socratic dialog. In a Socratic dialog, the “teacher” never answers the question directly. Instead of giving an answer to the student’s question, the teacher replies with a question until the student sees the answer him/herself, until the answer comes from the teacher who lives within the student, until the student becomes the teacher him/herself.

What are your research or other scientific interests?

During the last several years, my research has been more towards better methods of teaching and writing in science and in general, how students can be more successful in maintaining sustainable happiness and real personal growth. To that end, with the help of one of my past students, Brian Tu, there is now a website with a lot of material related to “Success in College and After College: How to Get and Stay on Course.” In addition, I am teaching a freshman seminar with the above title every quarter. That seminar grew out of informal lectures I used to give every quarter on the same topic. My other scientific interests are in green chemistry.

How did you get interested in life planning?

That is a good question. I feel I could write a series of books on the subject. As always is the case, any one of us suddenly can become a living spring of water from his/her life experiences. In my case, I always liked teaching and learning. I knew that from my first college years. But life circumstances caused me to drift away to work in various other work environments related to chemistry. Being so thirsty for expression and the discovery of human nature, I could not take being away from an academic teaching environment anymore. The issue became an issue of life and death; it was so strong. So I suddenly started on the new path by choosing to leave a very high-paying permanent position to take several temporary very low-paying positions. I know it sounds crazy but it happened, and it had a great impact on all the members of my family. I was very lucky to have the full support of my family.

What advice would you give a student on how best to choose a good career?

I would like to keep this answer short so anyone who reads this will always remember it. No pain, no gain. It is not without pain that we come to know who we are. By finding out who we are more every day, it is possible to “do” what we are. And by doing what we are, we are definitely home, gravitating effortlessly towards total success. Unfortunately, to have total success in life, inwardly and outwardly, a high GPA is not enough. To do what we love is very important but it still is not enough. Only if your personality type matches with what you are doing, where, how, when and with whom, then real success is within your reach. Therefore, I say to my students that if you want to be a success, know who you are.

Do you have any hobbies?

Yes, I have several hobbies. I love taking walks and spending time in nature. To that effect, I have gardens not only at my house but also at the Experimental College provided by the university. I encourage my students to get gardens so they can recalibrate themselves after studying and feel good about themselves. Some of them have responded. It is a great pleasure to meet them at the gardens and see them working with the soil and the plants. If you go to my personal website: http://andtou.freehostia.com/index.htm you will see several pictures of the products of some of my hobbies.

I also took a class on how to make soap and now I am making it from all natural components. In order to encourage my students to have hobbies, I thought of the “Natural Soap Award,” as I call it. For each class I teach, at the end, the student with the highest score gets a handmade soap. When they come to my office to pick up their award, while I am carving the “life curve” on it, I have the opportunity to tell them face to face how important it is to know themselves. I consider it very important especially for the students with high GPAs to be balanced in life. After all, most of them will end up in leadership positions and many people will be affected by their decisions. We must prepare these students the best way we can. I stress the fact that doing their work right would not be enough without considering the well being of others and our environment.

Who is your favorite scientist?

Albert Einstein is my favorite scientist, not only because of his bringing truth to science but because of his excellent personality and life values that perhaps most people are not aware of. Another reason is because of the way he spoke about my favorite person, Gandhi. “Generations to come will scarce believe that such a one as this walked the earth in flesh and blood,” -Albert Einstein, in regard to Mohandas Gandhi.

Do you have a favorite quote?

“You Must Be The Change You Wish To See In The World,” –Mohandas Gandhi.

UC Davis research physicist Richard Breedon and dean of mathematical and physical sciences Winston Ko are just a couple names from a group of UC Davis faculty working on the world’s largest and most powerful particle accelerator, the Large Hadron Collider.

“UC Davis was one of the very few American groups in particular that started in the very beginning,” Ko said.

In 1992, UC Davis was one of only four American institutions to sign the letter of intent for the international collaborative effort to construct the Compact Muon Solenoid, one of the general-purpose detectors of the LHC. Breedon and Ko, as well as retired physics professor Richard Lander, were the signatories, Ko said.

The LHC is an international research venture based at the European Organization for Nuclear Research, also known as CERN. Researchers, engineers and scientists from 111 countries are working together on one of the largest scientific experiments ever accomplished, according to the Large Hadron Collider’s website.

First powered up on Sept. 19, it was shut down because of an unexplained leak of liquid helium. CERN expects the maintenance will be completed and the LHC ready to operate by April.

One of the many purposes of the LHC is to create collisions between opposing beams of protons up to nearly the speed of light in order to understand the origin of mass after the Big Bang.

Also, by trying to understand the origin of mass, physicists hope to discover the Higgs Boson, the theoretical particle in the Standard Model that has yet to be seen. The Higgs Boson explains how massless photons with large amounts of energy can attract other particles to become mass.

“Particles go through the Higgs field and like a ball being dragged through sand, it accumulates mass,” Ko said.

Another aspect Breedon said he is most excited about is the prospect of supersymmetry, which predicts the existence of many new particles for physicists to discover and study, with the lightest particle being an excellent candidate for Dark Matter.

Hypothetically, Dark Matter and Dark Energy account for the vast majority of matter in the universe. Scientists have yet to prove its existence but hope that with the LHC, evidence will be found.

If supersymmetry exists, while some supersymmetric particles can be discovered with the LHC, to really understand them requires a new machine, a linear collider that will collide electrons and positrons. The development of such a machine, which is decades away, has begun as a truly international effort called the International Linear Collider, Breedon said in an e-mail interview.

“I expect substantial progress in understanding Dark Matter within a decade,“ he said. “Elucidating the Higgs field at the LHC and ILC could be a first step toward understanding Dark Energy, but that will certainly take much more time.“

If either the LHC or the ILC discover supersymmetry particles, it will, in turn, help clarify our understanding of how the universe came to be.

“It will show that the smallest [particle] is connected to the biggest [explanation],” Ko said.

NICK MARKWITH can be reached at campus@californiaaggie.com.