The Oceans; A Physical Geography

Friday, April 6, 2007

Great Barrier Reef: Gone in 20 years!

Biologists are saying that their is a great concern for the worlds great barrier reefs. If some drastic changes don't happen soon, the great barrier reef could be dead within 20 years.

There needs to be a huge cut in the greenhouse gas emissions or there will be drastic changes occurring. Because of the rising temperatures, and as a result rising sea temperatures, the corals that live within the sea are becoming bleached and dieing. Not only are the corals being bleached, the rising temperatures are making the oceans become more acidic and is preventing the corals from being able to create their limestone skeletons. he rising temperatures of the sea plus the increase in acidity could be harmful and deadly for the reefs of the oceans. If things keep going the way they are going, within 20 - 50 years there could be no more living corals within our oceans. This is not the first we've herd of this, the warning signs have been around for a couple of years now. This has been around since 1998, when there was a major bleaching event that occurred in the oceans causing an alarming 16% of the worlds corals died.

Global warming is not only having an effect on the worlds oceans, this is also affecting the rain forests and glaciers. Something needs to be done and it needs to be done today. If hings keep going the way they are going then the worlds oceans, rainforest's, plants, animals and us will suffer the consequences.

Thursday, April 5, 2007

South Pacific Tsunami

The Solomon Islands are located in the South Pacific Ocean, off the coast of Australia. On Monday, April 2/2007 (3 days ago), The tiny islands were in devastation as an earthquake, measuring 8 on the Richter scale. This triggered a tsunami warning, but after several hours of not being struck, by the massive wave,the danger period passed and the warning ended. A short while later, the small islands were struck by a tsunami. Ten feet of water was rushing through the towns, buildings along the waterfront were destroyed. Police in the town of Gizo reported seeing a wave several feet high crashing ashore, but then the communications were lost shortly after.

The quake struck at 7:39am, about 10kilometers beneath the saeas surface and 350kilometers northwest of Honiara. Since it measured so high on the Richter scale, the Hawaii-based Pacific Tsunami Warning Centre thought this could trigger a tsunami and issued a warning for the Solomon Islands and their neighbour Papua New Guinea. When Honiara received a 15-centimeter wave, the warning was cancelled.

After reading an article today, Thursday April 5/2007, on the oceans channel, there is still no aid at the islands and it is several days away. Thousands of people have been left homeless and things may remain that way for another couple days. Rescuers are struggling to reach the remote villages of the islands. At least 28 people have been killed and there could still be more.

Sunday, April 1, 2007

The Living Ocean

The worlds oceans are a very diverse place. Many different types of flora and fauna call the ocean home. Species can be found throughout the entire ocean, from the top, sunlit areas, to deep down where no light can penetrate and some species even live on or within the seafloor. The ocean can be divided into two general zones; the pelagic zone, also known as the water environment, and the benthic zone, also know as the seafloor environment. The pelagic zone can be divided into sub-categories. They are the coastal, or neritic zone, the area above the continental shelf, and the oceanic zone, the area of open ocean away from the direct influence of land. Depending on the depth, the benthic and pelagic zones can be further divided.
The most abundant organisms found in the ocean are called microbes or microorganisms. They are single celled organisms and they carry out a variety of processes. They are very small in size compared to other marine species, averaging about a few microns. Invertebrates, fish and whale species can be seen really easy compared to microorganisms. Most of the other species found in the ocean, like invertebrates, fish and whales, are considered multi-cellular organisms. This means they have several cells that interact and form tissues, organs and limbs. There are many other types of organisms that make up the food chain withint the oceans. The next species up from microorganisms would be plankton, then zooplankton, nekton, benthos and larger species.
There are many complex interactions that occur in the ocean. Species. The marine environment is made up of a variety of different ecosystems, with diverse communities. Species are grouped together based on either their relatedness or their function. Species can either be prokaryotes, unicellular organisms, with no internal membrane structures, or eukaryotes, unicellular or multi cellular organisms containing internal membrane-bound cell structures. After determining if the species belongs to the group of prokaryotes or eukaryotes, they are then further categorized by kingdoms, families, classes, orders, etc. This is a process known as taxonomy. Taxonomy is based on species who share common morphologies.
Species can also be categorized in two general types, based on how they obtain energy. First there are autotrphs, which generate organic matter from inorganic matter. Then there are heterotrophs consume the organic matter by consuming autotrophs.
Life in the ocean does no only stop at the species and what groups they are in, but there are other factors to be considered when looking at life in the oceans. Things like carbon, salinity, temperature, etc. Since the oceans are so diverse and complex, it is what makes them interesting and fun to learn about.
Read More~>
~Chapter 14 in "An Introduction to the World's Oceans", by Keith A. Sverdrup and E. Virginia Armbrust.

MarineBio.org

As I was searching the Internet to find something to write about in my blog, i came across this really cool website MarineBIO.org, and was Reading some of the articles. It has really interesting links about marine species, marine conservation, global warming, sustainable fisheries and then I came across another link about marine endangered species. I started looking through the list and I was absolutely shocked at the number of endangered species are listed on the ICUN red list. There are over 1,300 endangered marine species ranging from whales, dolphins, manatees and dugongs, salmon, seabirds, sea turtles, and sharks. It is amazing how this is all happening around us and a lot of people don't even have a clue about it. I know that I didn't know that there was that many marine species on the endangered list. I think governments and scientist should really start doing something today before those species go from being endangered to extinct. If there is mass extinctions in the oceans, then it will not only cause problems in the oceans, but for us on land too.

Saturday, March 31, 2007

Seaweed: The Oceans Forest

Seaweed are forms of algae and are marine plants. There are three basic types of seaweed, brown, green and red. Brown seaweed has about 5000 different species, green seaweed has about 800 species and red seaweed has about 2000 species. Seaweed is attached to the bottom of the ocean by holdfasts. They provide shelter and food sources for many species within the ocean. Some species of seaweed can grow several meters in length or be very tiny. They stay a float with tiny gas/air pockets. Seaweed an be found in all of the worlds oceans and is usually located in sandy bottoms or attached to rocks in intertidal zones. Seaweed is not considered a plant because it lacks the specialized vascular system. Like plants, seaweed is photosynthetic, converting energy form the sun into energy. Seaweed contains chlorophyll and seaweed can also contain other light absorbing pigments like red, blue, brown or golden, which provides the pretty colouration seen in red and brown seaweeds.

Seaweed is not only beneficial in the ocean. It is used as medicines and eaten by humans and sometimes used as fertilizer.

Friday, March 30, 2007

Sharks; 'Heading for Troubled Waters'

In today's newspaper, there was an article titled "Heading for Troubled Water", a study done by Dal Housie and the depletion on the worlds sharks. Many of the worlds sharks are near extinction and it is thought that this extinction is causing a serious/dangerous ripple effect in the marine food-chain. A study has been done, and it shows that there is a disappearance to depletion of other marine species. The species that sharks use to prey upon are now having a huge boom since there is not as many sharks around to prey on them.It has been shown that there is an increase in about a dozen smaller sharks, rays and skates and this has caused a cascading effect throughout various ecosystems because they are depleting the limited amount of nutrient sources, which is altering natures complex food webs. It is thought that since the larger animals are being disproportionately hit by overfishing, that it is effecting everything beneath them in the food web. This is restructuring the oceans food web and how it operates.
Scientists are now thinking that the shark populations are lower then what was previously thought. One of the main sources for this huge decline is the practice of finning the sharks then throwing the carcasses back overboard. Since there is such a huge decline in the top predators, there are not enough of them around to be fulfilling their roles in the food web and therefor no longer controlling the species below them. Not only is this having effects in the oceans, but it is having effects for communities that depend/thrive on healthy fisheries. Scientists are not yet sure of what this means for the oceans food web, but they do think that the greater increase in other species will disrupt the wider natural order in all the oceans world wide. It is estimated that the population of the rays alone has increased about ten percent.
Scientists only thought that this could happen in smaller ecosystems like ponds, but seeing it in the marine environments has become very alarming. Scientists are now seeing why one species, like the sharks, can be so important to the entire world and how it can disrupt the flow of energy.
Now that scientists know, they should be spreading the word around and start enforcing laws so that the populations in the oceans can get back to normal and their is not a mass extinction like what happened with the dinosaurs.
Read More~>
~ http://thechronicleherald.ca/NovaScotia/567675.html

Sea Turtles

Sea turtles (Chelonioidae) can be found in all of the worlds oceans except the Arctic ocean. Some species of the sea turtles do not just live within one ocean, but they travel between different oceans. The Leatherback Sea Turtle is the largest of the sea turtles and measure about 6-7 ft in length and 3-5 ft in width and can weigh up to 1300 pounds when it reaches sexual maturity. Most of the other species of seat turtles are much smaller in size, averaging about 2-4 ft in length and much smaller in width. There are seven different types of sea turtles, they are Kemp's Ridley, Flatback, Green, Olive Ridley, Loggerhead, Hawksbill and the Leatherback. All of them, except the Leatherback, belong to the family Chelonioidea and the Leatherback belongs to the family Dermochelyidae. The sea turtles are distinguished/identified by different features they have. Some of these features are scales on the head or the number and shape of scutes on the carapace. The Leatherback sea turtle is the only one that does not contain a hard shell covering its exterior, instead it has a mosaic of bony plates that are beneath its leathery skin.

Sea turtles have a very good sense of both time and location. They are very sensitive to the earths magnetic field and they use it to help them navigate. Sea turtles, if given the chance, can live up to 198yrs. Most sea turtles head back to the location where they were born to nest, which means that location must have imprint in its magnetic features. Most species nest individually, but the Ridley turtle go ashore in one mass, known as the "arribada" (arrival). The kemp's Ridley, this happens on the beach during the day and only on one particular beach in the entire world. There use to be larger numbers, but now, there is an extensive amount of poaching and hunting for turtle eggs, which has lowered the numbers. It is illegal to hunt turtles, but they are caught worldwide, mainly for the food industry. Some of them are even hunted for their shells. Turtles are very important, not only to humans but to the oceans and beaches as well. If turtles were to become extinct, then there would be a significant negative impact to the beaches and oceans.