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View Full Version : Ocean as a desert - discussion


SamFamAustin
12-01-2006, 08:39 PM
Pellucid made an interesting comment on the AMB forum about the Abacos not being able to support a lot of bird populations like gulls and pelicans because the ocean was basically a "desert" devoid of nutrients.

I'm not disputing that in the least although I do have some comments, like how vast stretches of the Gulf are a real desert except for the occassional reef, canyon, or oil & gas rig. Now to me that's really a desert, with absolutely nothing growing!

Perhaps Pellucid might be saying that there is absolutely no nutrient flow from the wetlands, which are quite extensive in the Gulf of Mexico. There in the wetlands, crabs, worms, birds, and small bait thrive, allowing breeding and juvenile areas for fish such as snook, flounder, redfish (drum), sea trout (weakfish), and so forth. Call it a sandy mud thang, maybe.

Not being an aquatic biologist, I can say that the reef ecology of places such as the Abacos is quite a miracle because it lacks nutrients inflows from wetlands such as decomposed nitrogen, phosphorous, and trace metals such as zinc.

However, there is something called "ocean upwelling" that is able to stir up vast amounts of nutrients from the depths of the ocean. These can be caused by current eddies spinning off the Gulf Stream and interestingly, there are some currents and eddies which form east of the Abacos and join up with the Gulf Stream as well, to the north.

It is a fascinating subject but my limited understanding is that such current eddies can sweep up large quantities of plankton and nutrients, which attracts the bait fish and then the pelagics. That is perhaps why the Abacos has much better offshore fishing than other places along the Atlantic Coast, even Florida.

What is not clear in my mind is how the reef ecology does so well, since the eddy currents are several miles out to sea. Something keeps them going. Believe me, with the over-fishing experiences all along the Atlantic and Gulf coastlines, you're loaded with fish. It's just that there's not many birds.

Any ideas?

oldoc2
12-04-2006, 06:33 PM
Sam: the warm waters of the Bahamas, including south Fl. do not support plankton and small fish. The reefs support some fish but in numbers the waters of Alaska, Labrador, the great "Banks" off the east coast are, despite massive abuse, fish nurseries. I recall the giant Tuna feeding on the Stellwagon Bank off the Cape-they stayed all summer on into the fall.
There is no single answer to the question-of why no birds- but generally it is a lack of easily avalable food.
Let me add, that it is often the interface between thermoclines that is richest in plankton, small fish, bigger fish and so on.
Forgive my two cents!

SamFamAustin
12-04-2006, 07:56 PM
I think I catch your drift, although I might dispute that the Banks off Cape Cod and Maine really have any fish, as they are for the most part closed to fishing - modern day deserts. A few boats do fish the Gulf of Maine in search of Blue Tuna and a few cod, although very few are left, my friend. If it wasn't for the inshore commercial lobster and recreational striper, there would be almost nothing to speak of, and the other fisheries are in a complete state of collapse.

Thanks for posting and you're right, the plankton should be plentiful up there.
/Sam