Tag Archives: Ocean

The Seaweed is Always Greener in Another Pond

When you ask a group of people to name Earth’s most important group of organisms you’ll receive a variety of answers. Regardless of whether or not they have a scientific background, you will rarely hear anyone say algae. However, as more and more research accumulates, it is becoming clearer and clearer that the correct answer might just be algae. That’s right, that weird green and red slime that you see at the beach is by far one the most important group of organisms on this planet.

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Courtesy of Arthur Chapman via Flickr Creative Commons

Whether it is green, brown, or red, algae are the most important organisms you have probably never considered before. Consider the following: the breath of fresh oxygen that you’ve been enjoying while reading this sentence, as well as every other breath you have taken in your life, is mostly thanks to oceanic algae. In fact, it is estimated that about 70 – 80% of the oxygen we breathe is a product of algal photosynthesis. This is an astounding figure, especially when most people consider our forests to be our source of O2. And it’s not just oxygen that algae provide humans with.

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Courtesy of Oregon State Parks’ via Flickr Creative Commons

Have you ever enjoyed a nice scoop of ice cream on a hot summer’s day? Have you ever enjoyed a dairy product, or bread, or canned meat? If the answer to any of these is yes, then you might just have to send thanks to algae. Algae are a source of agar, which acts as a thickener, and is an additive in nearly everything, from food to cosmetics. Agar is also irreplaceable in fields of science such as biology and pharmacy where organism growth is a key part of research.

Courtesy of Kate Donkin via Flickr Creative Commons

Algae don’t just provide a medium for biological and health related research – even before the emergence of science, as we know it, Corallinae algae were used for thousands of years as an anti-worm remedy. Nowadays, algae are still used in the healthcare industry. Corallinae, with their structure and calcium content have been found to greatly enhance bone regeneration, extracts from the Dumontiaceae algal family have been shown to inhibit the herpes virus in non-human patients, and Carrageens, which are extracted from red algae, are currently an active ingredient in a number of anti-viral drugs.

Recently, algae have begun to play an even more important role in our lives. With global warming becoming a larger and larger concern, Exxon, BP, and Chevron have started to grow and harvest large quantities of algae for biofuel. Not only does the use of biofuel prevent the environmentally destructive harvest of non-peak oil, but the growth of large amounts of algae also acts to remove a significant amount of C02 from the atmosphere. On a smaller scale, a French scientist has started working on a unique algal lamp. These lamps, using just oxygen, a small internal light source, and photosynthetic algae produce both light and oxygen, consuming only CO2. And the quantity of CO2 is substantial – it is estimated that a single lamp uses 150-200x the amount of CO2 annually that a tree will use in its lifetime.

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Courtesy of shamengo2 via Youtube

Although you wouldn’t usually think twice about them, algae are, in a lot of ways, the cornerstone of life as we know it.

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– Abby Perehudoff, Clarissa Ngui, Brian Kahnamelli, Jong Jin Park

Salty Sea

Ocean
Copyright: Best Wallpapers

Starting in the 1500s, many geologists began to estimate the age of the Earth using faulty sources and theories. For example, James Ussher estimated the age of the Earth to be over 6,000 years old based on the timelines given in the Bible and other historical events. One of the estimation that stood out was made by John Joly, an Irish geologist. In 1899, Joly published a paper estimating the age of the ocean, which he believed to be the same age as the earth, to be 90 million years old. He made his estimation based on his idea that the ocean started out fresh and as the Earth grew older, the ocean grew proportionally saltier also. However, this idea has been proven wrong today with our understanding of the ocean.

Process of Weathering and Evaporation
Copyright: Woods Hole Oceanographic Institution

There are many ways that the ocean gets saltier. For example, weathering, hydrothermal vents, submarine volcanoes, as well as evaporation of the ocean. The process of weathering is a condition caused by the sulfuric-containing rain falling on rocks and sediments that causes it to release minerals that are contained within. When these minerals are released from the rocks, they are then transported from the river to the ocean. This increases the overall salinity of the ocean. A second way to increase the salinity is from the hydrothermal vent sat the bottom of the seafloor.

Hydrothermal Vents
Copyright: USGS

At the hydrothermal vents, high pressure and high temperature causes the degradation of the sediments at the oceanic floors, which in turns releases minerals trapped within to the surrounding waters. Similarly, the submarine volcanoes releases minerals in the same way. Finally, the most well-known method to increase the salinity of the ocean is through evaporation of the ocean. When the ocean undergo evaporation on a hot day, it leaves behind the salts in the ocean while the water particles moves itself into the atmosphere. Therefore, evaporation is the most readily method to increase the salinity of the ocean and this is most evident in areas of high temperature.

 

Coccolithophore: an example of marine organism requiring calcium for shell
Copyright: Great Belt Research Cruise

While there are many ways to increase the salinity of the ocean, our ocean is not, by Joly’s theory, getting saltier with time. The reason for this is due to the plate tectonics movements as well as the circle of life of marine organisms. Firstly, when an oceanic plate collides with another continental plate, the oceanic plate tend to collide below the continental plate into the earth. When this happens, the salty minerals-containing sediments are buried deep within the Earth and therefore removing the salt in the ocean. However, the seafloor tectonic plates movement is also the cause for tsunami. Secondly, the ions in the ocean are required by marine organisms to survive. For example, these organisms require sodium to survive and calcium are needed to build skeletons and shells. When the organisms take up these ions, they also contribute to the removal of salts from the ocean. Therefore, although the ocean does get salty with time, as James Ussher predicted, the ocean also provides mechanisms that removes the salts. This is due to a phenomenon called the steady state where the ocean reaches an equilibrium between the rate of addition of salts and the rate of removal of salts.

YouTube Preview Image This Youtube video demonstrate how the plate tectonic collides at the seafloor.

-Vivian Wu