open ocean habitats

The video on open ocean habitats that we watched in class was very interesting. I had never really thought about the types of living conditions that occured in open ocean environments. Most videos and photographs that I had seen this semester involved the ocean floor, or coastal areas. However, I know that the oceans are cast and now I am able to see that many forms of marine life are occuring in these open areas. I especially liked the section that involved that small fish eating bacteria and such off of larger species for food, and in turn cleaning off the larger fish. It is interesting to see the way that species in the oceans work together like this. I also liked the section about fish using trash and floating debris for protection and hiding purposes. In such large, open areas, there would be few places that fish could hide. It was suprising to see that floating nets and other trash like buckets could be used to hide out in. Like the video said, trawling nets that normally destroy marine habitats can be used for protection when they are floating in the open ocean.

Humpback Bubbles

Today in class one of the groups discussed the bubble net fishing method of the humpback whale. Previously, I had never heard of this bubble feeding. I found it very interesting and unique and decided to do a little research of my own. On the left I have an image of a whale creating a bubble net. As the whale swims upwards, it slowly begins to spiral. While doing this it blows bubbles creating a bubble net that is free of bubbles in the middle. The fish, afraid of the disorienting bubbles, remain within the calm centre of the net. Finally, the whale swims up through the net with its mouth open, which is know as "lunge feeding" and swallows the fish that are swarmed in the middle. Apparently, as mentioned in class, other whales help to blow bubbles on the net to intensify the bubble wall, and more make loud noises to further disorient the fish. This is also a cue for all of the whales to be ready to lunge at the same time. Furthermore, accoustics in water reacts differently with bubbles compared to bubble free water. The bubbles keep much of the sound within the net (the bubbles act as a sort of barrier), which allows for more efficient disorienting of the prey in terms of noise. On the top is a photograph of the bubble net as seen from the surface. I found this all very interesting, the way the whales work together in order to all get a nice lunch.

Sable Island, being off the coast of Nova Scotia, is a very isolated area. I was interested in finding out the quality of the Ocean near the island in terms of pollution. Because it is isolated, I figured there would be very little pollution. However, I was incorrect. I found a study conduscted in to 90's about pollution in the area, mainly pieces of trash and garbage. It turns out that each month 200 pieces of trash float ashore per km of coastline. (This is just counting plastics). Sable island is approximately 40km long, so this trash washes onto the shore at a rate of about 8000 pieces a month. Considering the isolation and lack of human population, thats a lots of trash. The island is home to many forms of marine life. Since there is a lack of humans generally in the area, the island provides isolated beaches and such for marine species. Trash and garbage pieces float ashore and disrupt their haibtat. Pictured above are a herring gull and a seal caught in plastic in 2002. Another negative impact that this garbage has is on search and rescue. Apparently, when rescue missions are required in the area, it is often difficult to distinguish between the search mission and pieces of trash (rescuers can't see the people in danger, or they mistake it for garbage). So even though we are polluting areas along our own shores, humans deposit great amounts of trash that flot long distances and can have severe impacts many miles away.

Overfishing

This is an image that I found that represents overfishing in many areas. Although it is only a cartoon, I think it does a good job at displaying the issue at hand. Basically, so many areas of the world's oceans have been overfished that there are hardly any fish left to catch. At one point, there were so many fish that people believed that the oceans could never be overfished and people took whatever amount they pleased. However, like most resources, when extracted too rapidally without allowing time for renewal, the resources can dissappear. This is especially true with fishing and I think that it is terrible that in many cases it is almost too late. If used in oderation, many species of marine life would be able to replenish itself, but with the speed that many types of fish and other life in the oceans have been caught, they were unable to do so. Fish are thought to have been one of the first creatures on Earth, and they were around a long time before humans. Furthermore, the first vertebrates are decendants of fish. This being said, we are extremely distand ancestors of fish and they have inhabited this Earth for millions of years longer than humans, it is a shame that it is taking an extrememly short amont of time in respect to Earth/marine life history for us to overfish and destroy many species.

Halifax Explotion Tsunami

Until discussing tsunamis yesterday in class, I didn't realize that Halifax had ever been affected by one. Although not caused by geological processes like most tsunamis are, it still managed to reach heights of 18 metres above the high water mark in Halifax. The wave was so strong that it washed the ship Imo ashore on the Dartmouth side where it stayed until the following spring. It is inateresting to find out that there are no official records or accounts of the tsunami itself. Many people were already dead form the explotion, and the people and buildings that were in the immediate downtown areas had already been destroyed before this wave hit. However, in 1918 a man by the name of Archibald Macpherson interviewed survivors and wrote an article about their accounts of the explotions. A firefigter named William Wells survived both the explotion and then encountered the tsunami, and this is what he told of his experience:

"The force of the explosion flung (Wells) across the street against a telegraph, or electric light pole. His own account is that he left the engine, or the engine left him, he did not know which, but anyhow they parted company. There he lay until the sea drove over the road, washing him as far as the middle of Mulgrave Park. He was drenched and almost drowned and when picked up was not expected to live. He did, however, recover and regained his usual health."

Tsunami

This photograph shows tourists literally running for their lives from a tsunami wave in Asia December, 2004. After discussing such waves in class today I was interested to see more footage. After watching many videos I realized that most of them show people standing around staring at the waves. It is terrible that they had absolutely no warning at all. This photograph shows people running at the last minute. Many people thought the waves looked like interesting big waves coming toward them and did not realize just how big and dangerous they were. I am sure that after such events, major research projects and warning systems have been set up in the area. However, before the 2004 tsunamis, no such tracking/warning station was set up. It makes me wonder what sort of losses could have been avoided if there had been more warning. Although there had been no recent destructive waves in the area prior to these events, there are records and signs of massive destructive waves along many coastlines from many years ago. If they were possible then, and seismic activity triggers them, which we already knew, another destructive event was clearly possible. It is unfortunate that it took such a catastrophe to occur for more research and planning projects to go into the this area of ocean.