Must be in APA format with a minimum of 300 words with references: Discuss the role of dissolved oxygen and how and what fish actually breath. Please read below
If all oxygen in seawater comes either from exchange with the atmosphere or from photosynthesis by phytoplankton in the euphotic zone, how do you explain that there is sufficient dissolved oxygen throughout the water column, even in the greatest depths, except in highly unusual locations? Now this will also relate to the Forum Topic for week * how did photosynthesis allow life to come out of the ocean and on to land? Here is a hint: it has to do with temperature, think about WHY they keep lobster tanks so cold in grocery stores. Please read the section below and the attached articles about lobsters..
Okay there is good news and bad news about lobsters:
The Good News : They taste great and are less filling especially with melted butter. By the way the claw bands are color-coded by size: yellow=1-lb, red=1.5-lb, blue=2-lbs, etc).
Also New England lobstering is the most regulated fishery you’ve ever seen. The states of Massachusetts, New Hampshire and especially Maine have very strict lobstering regulations and they are enforced stringently. All lobster traps have to have state identification tags, catch limits are imposed and lobstermen can only sell to “licensed dealers” thus the states can track the catches from seafloor to the market or the restaurant table. The penalties for catch undersidezed (or in Maine oversized, the reproductive stock) are severe: lobstermen can loose their license, traps, boat, and be heavily fined. But it is a way to keep people honest and thus protect the populations.
The Bad News : Both lobsters and crabs are SCAVENGERS (they eat dead nasty stuff) thus their bodies are full of bacteria . So they have to be kept alive until they cooked because their meat starts to spoil as soon as they die . So if you ever see them on ice in a seafood counter check them out they’ve been cooked! Some places will cook ’em if they look like they’re gonna die so they can still sell ’em. That’s also why they should be cooked thoroughly to kill the bacteria.
Now some soft-hearted folks can’t bear to put them directly into boiling water so they put them in cool water and bring it to a boil believing that the lobsters won’t suffer as the water heats. But here’s the deal: since lobsters can’t osmo-regulate (control the salt-levels in their tissues) they tend to die quickly once they are put in a pot of fresh/tap water because they can’t stand zero salinity thus they are dead well before the water boils.
In contrast blue crabs are called osmoregulators (they can adjust the salinity-levels in their tissues) thus blue crabs can stand open-ocean salinity (35/1,000) all the way down to almost fresh water (0/1,000) which is why they do so well in estuaries. Open and check out this cool power point about blue crabs. The pictures are great. BlueCrabproject.pptx as well as the article about scientists have just now learned to determine the ages of lobsters accurately.
Watch this very cool video: Attack of the Lobster Cannibals! www.youtube.com/watch