Swim Bladder

One of the ways fish swim down to great depths is to use swim bladders, or gas bladders. These are basically air sacs located within fish to help them regulate their boyancy. The question becomes how does that help anyways?
Oxygen is much more plentiful in the atmosphere than in water. On average there is 210 cubic centimetres of oxygen in one litre of air compared to 10 units in water.
Swim bladders help fish dive to great depths and return to the surface. Some fish must inflate their swim bladders from the atmosphere and others can inflate it by diffussion of oxygen from their lungs. I wanted to quickly look at the evolutionary history of this fish and I found this interesting article that states swim bladders from fish that use the oxygen method to control buoyancy are all related. This means the evolution of this type of method evolved just once. So this is my little post. If you're dying for more biology related information go here.


The earliest fishes, as well as modern cyclostomes, sharks and rays all live without a swim bladder.

Seiches

This phenomena is basically a standing wave in an enclosed/partially enclosed body of water. It can seem to be lunar tidal related but I don't think it is. This phenomena is equivalent to the sloshing of water in a bathtub and there is a nice diagram explaining the phenomena here. It is basically the sloshing around of water in an enclosed area due to prevalent winds pushing water in one direction. Once the wind stops blowing the water returns from the direction it came from. The movement can seem tide like but it isn't directly related to the sun or moon, such is the case with neap and spring tides. As always, there is more information available from wikipedia.

Lunar Tides

Tides are basically the rise and fall of the sea surface relative to land. They are basically produced by gravitational forces from the Sun and the Moon. Two major lunar tide types are Spring Tide and Neap Tides. The NAOO has a nice little diagram of how both occur. Spring tides occur when the moon is full/new and the gravitational pull of the sun are combined. Neap tides occur when the moon and sun are at right angles of each other. The end result is that Spring tides have higher highs and lower lows and neap tides are less intense tides. Check out this site for more information.

HARBOUR WAVE!!!!!!!!!!!!!!!!!!!!!!!!!!

Harbour waves don't bring up the same mental imagery of a TSUNAMI but they mean the same thing. I also found the Canadian Geographic website, which has a great article about tsunamis and how they form. It also has air photos of before and after a tsunami struck. I just don't know how to link these into this blog thing.
I find the article interesting because it points out that the mental imagery of a tsunami is not really the same as the real thing. Tsunamis are not a single huge wave engulfing our coasts.
Tsunamis form by earthquakes or some other cataclysmic event that allows water to rise. In open oceans tsunami waves are barely visible, sometimes being no more than a meter or so high. They don't get dangerous until they hit the coast and it is the shallowing of the land near the coast that makes a tsunami bigger and consequently more dangerous.
That is my lesson for the day.Make sure to check out the photo's!

Octopus Origins

Found this article in the Globe and Mail that was pretty interesting. It says that the deep sea waters of Antartica's Southern Ocean is the home of most of the world's deep sea octopus. So I guess we can say that deep sea octopus had this out of antarctica movement that had occurred some 30 million years ago.
What is interesting that Canadians are involved in this. One researcher is from Memorial University, located on The ROCK.

Great little discoveries like this make my day so much brighter

Tsunami Institute

Following our class discussion on Tsunamis, I found this website of the Tsunami Institute. It has some pretty interesting pages like Tsunami Formation. The diagram shows the tectonic influence in tsunami formation. There is also a really nice section on Tsunami Occurence which shows a map of tsunamis from a world wide perspective. You can even subscribe, for a price!, to their Tsunami Alarm System which will send you a message via satellite if a Tsunami were to strike. The important thing though is that as we learned in class there must be a tsunami detection system in place for this to work.

Pollution in the Bay

Here is a quick post about pollutants in the Bay of Fundy. This website says that it is because of the 'flushing' effect of the Bay of Fundy combined with the low population densities found around the Bay that contribute to it being relatively clean. The take home point is the word relative. It is not to say the Bay is pristine but it is relatively clean. Relatively clean means that the Bay has 2-5ppm of PCB's conmpared to 9-10PPm of PCB's found in the St. Lawrence estuary. I still think that 2-5ppm is alot but I'm no expert on the subject. I just think this is enough for me to stay away from sea food as a whole but to each their own. Pollution to me is more than about impacts to humans and animals of this generation. It is a legacy that we leave to those that come after us and if nothing else we should think of what sort of message we are sending out to those future generations.