How Sea Otters Can Reduce CO2 in the Atmosphere: Appetite for Sea Urchins Allows Kelp to Thrive

ScienceDaily (Sep. 7, 2012) — Can an abundance of sea otters help reverse a principal cause of global warming? A new study by two UC Santa Cruz researchers suggest that a thriving sea otter population that keeps sea urchins in check will in turn allow kelp forests to prosper. The spreading kelp can absorb as much as 12 times the amount of CO₂ from the atmosphere than if it were subject to ravenous sea urchins, the study finds.

The theory is outlined in a paper released online September 7, 2012  in Frontiers in Ecology and the Environment by lead authors UC Santa Cruz professors Chris Wilmers and James Estes.

"It is significant because it shows that animals can have a big influence on the carbon cycle," said Wilmers, assistant professor of environmental studies.

Wilmers, Estes, a professor of ecology and evolutionary biology, and their co-authors, combined 40 years of data on otters and kelp bloom from Vancouver Island to the western edge of Alaska's Aleutian Islands. They found that otters "undoubtedly have a strong influence" on the cycle of CO₂storage.

Comparing kelp density with otters and kelp density without otters, they found that "sea otters have a positive indirect effect on kelp biomass by preying on sea urchins, a kelp grazer." When otters are around, sea urchins hide in crevices and eat kelp scraps. With no otters around, sea urchins graze voraciously on living kelp.

Kelp is particularly efficient at sequestering CO₂ from the atmosphere through photosynthesis. CO₂ concentration in the atmosphere has increased 40 percent since the beginning of the industrial revolution, causing global temperatures to rise, the authors write.

Wilmers and Estes acknowledge that a spreading otter population won't solve the problem of higher CO₂ in the atmosphere but argue that the restoration and protection of otters is an example how managing animal populations can affect ecosystems abilities to sequester carbon.

"Right now, all the climate change models and proposed methods of sequestering carbon ignore animals," Wilmers said. "But animals the world over, working in different ways to influence the carbon cycle, might actually have a large impact.

"If ecologists can get a better handle on what these impacts are, there might be opportunities for win-win conservation scenarios, whereby animal species are protected or enhanced, and carbon gets sequestered," he said.

Mitigating increased CO₂ in the atmosphere is a pressing issue in global environmental conservation with many obstacles and no easy solutions, the authors write. They note that markets have been established in Europe and the United States to trade carbon credits and thus inject an economic incentive into either reducing CO₂ output or increasing CO₂sequestration.

They estimate that the CO₂ removed from the atmosphere via the otter-kelp link could be worth between $205 million and $408 million on the European Carbon Exchange. "An alluring idea," they write, would be to sell the carbon indirectly sequestered by the sea otter protected kelp forest "as a way to pay for their reintroduction and management or to compensate losses to shell fisheries from sea otter predation."

Globular Star Cluster With a Secret

ScienceDaily (Sep. 3, 2012) — A new image from ESO's La Silla Observatory in Chile shows the spectacular globular star cluster Messier 4. This ball of tens of thousands of ancient stars is one of the closest and most studied of the globular clusters and recent work has revealed that one of its stars has strange and unexpected properties, apparently possessing the secret of eternal youth.

The Milky Way galaxy is orbited by more than 150 globular star clusters that date back to the distant past of the Universe. One of the closest to Earth is the cluster Messier 4 (also known as NGC 6121) in the constellation of Scorpius (The Scorpion). This bright object can be easily seen in binoculars, close to the bright red star Antares, and a small amateur telescope can show some of its constituent stars.

This new image of the cluster from the Wide Field Imager (WFI) on the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory reveals many more of the cluster's tens of thousands of stars and shows the cluster against the rich background of the Milky Way.

Astronomers have also studied many of the stars in the cluster individually using instruments on ESO's Very Large Telescope. By splitting the light from the stars up into its component colours they can work out their chemical composition and ages.

New results for the stars in Messier 4 have been surprising. The stars in globular clusters are old and hence not expected to be rich in the heavier chemical elements. This is what is found, but one of the stars in a recent survey was also found to have much more of the rare light element lithium than expected. The source of this lithium is mysterious. Normally this element is gradually destroyed over the billions of years of a star's life, but this one star amongst thousands seems to have the secret of eternal youth. It has either somehow managed to retain its original lithium, or it has found a way to enrich itself with freshly made lithium.

Most of the chemical elements heavier than helium are created in stars and dispersed into the interstellar medium at the end of their lives. This enriched material then forms the building blocks of future stellar generations. As a result very old stars, such as those in globular star clusters, which formed before significant enrichment had occurred, are found to have lower abundances of the heavier elements when compared to stars, such as the Sun, that formed later.

Attempts Made By Johann Döbereiner and Johann Newlands to Classify the Elements

Johann Wolfgang Döbereiner began to formulate one of the earliest attempts to classify the elements. In 1817 Johann Döbereiner noticed that the atomic weight of strontium fell midway between the weights of calcium and barium, elements possessing similar chemical properties.

Ca   Sr   Ba     (40 + 137) ÷ 2 = 88 

40     88     137

In 1829, after discovering the halogen triad composed of chlorine, bromine, and iodine and the alkali metal triad of lithium, sodium and potassium he proposed that nature contained triads of elements the middle element had properties that were an average of the other two members when ordered by the atomic weight (the Law of Triads).

Li   Na  K         Cl   Br   I 

7     23     39           35    80   127

English chemist John Newlands (1837-1898), having arranged the 62 known elements in order of increasing atomic weights, noted that after interval of eight elements similar physical/chemical properties reappeared.  Newlands noted that many pairs of similar elements existed which differed by some multiple of eight in atomic number. However, his law of octaves, likening this periodicity of eights to the musical scale, was ridiculed by his contemporaries. It was not until the following century, with Gilbert N. Lewis' valence bond theory (1916) and Irving Langmuir's octet theory of chemical bonding (1919) that the importance of the periodicity of eight would be accepted. Newlands was the first to formulate the concept of periodicity in the properties of the chemical elements. In 1863 he wrote a paper proposing the Law of Octaves: Elements exhibit similar behaviour to the eighth element following it in the table. 

Why did the titanic sink even though it was deemed to be unsinkable?

RMS Titanic was a passenger liner that sank in the North Atlantic Ocean on 15 April 1912 after colliding with an iceberg during her maiden voyage from Southampton, UK to New York City, USA. The sinking of Titanic caused the deaths of 1514 people in one of the deadliest peacetime maritime disasters in history. She was the largest ship afloat at the time of her maiden voyage.

Figure of Titanic's hull

            How did the Titanic sink then? The Titanic was claimed to be nearly unsinkable and this gave passengers the false impression that it was a very safe ship. The Titanic struck an iceberg at around midnight on the 14 of April 1912. However, they have received warnings beforehand on there being pack ice around and even big icebergs. This is due to the fact that the ship’s “wireless” system was a bit faulty at the time when those warnings were issued and the radio operator just ignored most of the warnings.

            

What made the Titanic sink the way it did then? The Titanic was warned that there was an iceberg right ahead just 1 minute before collision and officers tried to ‘port’ the ship by swinging the bow around the obstacle and then swing the stern so that both ends of the ship will avoid a collision. However, this process was delayed by some error in relation of the message. Titanic barely avoided a head-on collision but the change in direction still caused the ship to strike the iceberg with a glancing blow. 

Figure of Titanic 'Porting around'

An underwater spur of ice scraped along the starboard side of the ship for about seven seconds; chunks of ice dislodged from the upper parts of the iceberg fell onto he forward decks. A few minutes later, all of Titanic’s engines stopped. The tear caused by the scrape caused about 7.1 tons of water to gush in every second. This filled up 5 of its 16 watertight compartments. However, the Titanic was only designed to have 2 of its compartments flooded and at most 3-4 compartments at different parts of the ship. This caused the titanic to tilt a bit and when pressure was mounting near the middle of the ship, this caused the middle of the ship to split into two and it just sank into the bottom of the ocean where the pressure is as high as 6500 pounds per square inch.

Term 3 Test Reflections

Our Science test was returned to us at last but I was sick on that day. Anyway, I got 38/45 which was a very good score considering how biology was not my strong suit and also, there were a lot of terms which I could not really understand but in the end, I still managed to pull through. I think why I did well this time was due to the fact that biology was not my strongest area in Science and I actually looked through the notes carefully to make sure that I understand everything. Time management was key as I had competitions and other commitments but studies was the top priority. Effective time management led to me being able to complete work and revise for the test sufficiently.

Term 2 Test Reflections

The Term 2 test will be centered mainly on physics, the topic on light which I am not that strong in. There will be some components on chemistry, about salt preparation. I had a target of 36/45 for the test, to at least get 80% but I did badly for the salt preparation questions which pulled down my score. I think I did improve in terms of my understanding of light throughout the term as a lot of emphasis was placed on that and in the end, the concepts got into my head.

2P07: Law of Reflection

It was a new term and it will be our first physics practical of the year. We will be experimenting with mirrors and light.

The experiment is as follows:

1. Place a plane mirror on a sheet of plain paper provided. Use a pencil to trace the outline of the plane mirror. Label the outline of the mirror as ABCD
2. Using a ray box, direct a ray of light at an angle, i = 20.0 degrees to P on the side AB of the plane mirror.
3. Use two crosses R and S to mark the ray incident on P and two more crosses T and U to mark the ray reflected from P.
4. Remove the plane mirror and the ray box. Draw a line OP normal to the plane. Draw a straight line through RS and TU. Let the line RS representing the incident ray meet the side AB at P. Let the line TU representing the reflected ray meet the side of AB also at P.
5. Use a protractor to measure the angles i and r and record in a table.
6. Repeat the experiment for different values of i.

From this experiment, I learnt about the law of reflection and how the angle of incident is always equal to the angle of reflection.