Gulf of Mexico Dead Zone

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
The GoM Dead Zone set a new record this year - 8,800 sq. miles. Over-nutrification from the Mississippi River. Below 2 ppm oxygen the Gulf goes dead.

Here's the histogram for past years. New record.
 
Jun 21, 2004
2,897
Beneteau 343 Slidell, LA
This phenomenon occurs every year in late summer. Thought that the deep water horizon oil spill may be a factor; however, the histogram indicates otherwise. Undoubtedly nutrification from the MS River has a huge effect; however, it is interesting that the greatest oxygen depletion occurs farther west around the LA / TX border.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Yeah, I believe the drift is west. Looks like it is Messing with Texas!
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
I call it the "Bayou Effect" Slow moving water and low surf because of marsh grass or literally a swamp, doesn't lead to Oxygenation of the Water.
However it is not really dead.
We love crawfish in Louisiana taken from stagnant swamps and bayous.
Catfish abound there also.
Note all the swamp entries just north of the RED Zone...
_____
The natural living habit along the LA coast also is shrimp breeding grounds and they don't need bottom O2.
_____
The Mississippi River, once thought to be DEAD, is now full of fish. The Chemical Oxygen Demand in the Big Muddy has been controlled for many many years. No longer is untreated sewage dumped in the River.

However...
Our Oceans are the real key to human survival, since they produce 95% of our worlds Oxygen supply and also the largest consumer of CO2.:clap:

Jim...
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
big bunches of specks:
Those speckled trout [specks for short] love to eat the shrimp and I love to eat both.:)
Trout flourish and live near the Oxygenated surface waters.

This time of year, the "Lilly Pads" and "Swamp Scum" abound which are O2 consumers too.
The nutrients from "Cow Poop" in the rain water run off is probably not the reason for the "area of interests". More likely rice, sugar cane, and swamp creatures.
This is the Navigational chart for that area. Note the Green area and that the Intercoastal Waterway is NOT along the coast.
Welcome to the most "Growing State" in the union. Delta mud.;)
Jim...

PS: I am not making light of the NOAA termed "Dead Zone" I read enough of their study to see it was seasonal. Just like the shrimp are.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
Oops I forgot, Budweiser beer drinkers Trivia.
Guess what grain is used to make Bud?
Tic Tic Tic...




Louisiana Rice!
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Actually this dead zone has been carefully studied and understood for 30 years or so and has a direct analogue - the Chesapeake Bay, where a dead zone is being shrunk by efforts to remove nutrients (nitrogen and phosphorus) from the tributary rivers. Like the Gulf of Mexico, the Chesapeake continues to receive an overload of nutrient, mostly from ag operation runoff. The nutrients promote the growth of algae and grass which then dies and as it rots and sinks to the bottom it consumes oxygen (BOD).

While you may see some species able to swim out of the zone and survive, others that do not or cannot swim out die. We saw this with the Chesapeake where the dead zone crushed our crab population and affected fisheries dependent on blue crabs. In the Gulf, it looks like large brown shrimp are an effected fishery:
https://coastalscience.noaa.gov/new...-shrimp-affected-by-gulf-of-mexico-dead-zone/
Since many large agriculture operations are non-point source nutrient dischargers it took a Federal lawsuit against the Bay states to reach a settlement where the states would impell a cleanup of their river water quality. Like Pennsylvania, you may find that Iowa and Arkansas legislators will be resistant and care little about what is going on off Louisiana and Texas.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
Here is the 2017 Shrimp Season in Louisiana. Guess Why. Then read why!

SHRIMP!
Jim...
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Yeah, looks like the white shrimp are fished out and the shrimpers are being sent after the less valuable brown shrimp. In Carolina as a boy they practically gave the brown shrimp away, we used them as bait and brought the leftovers home as a snack. Ma called us her little Indians!
 
  • Like
Likes: Rick486

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
looks like the white shrimp are fished out
Sorry, but this is the reason from my link on SHRIMPS...

"to close any portion of Louisiana's inside waters to protect small juvenile white shrimp"

Oops shrimp are born and grow in the DEAD ZONE.;)

New opening date showed just this morning for shrimp after I posted the link. Reopening now August 18.:biggrin:

This is what is that Louisian Dept of Wildlife and Fishery [LDWF] Said this morning at my posting time....
"Data collected in recent weeks by LDWF biologists indicate increased quantity, distribution and percentage of small, juvenile white shrimp within these waters. The closure will protect these developing shrimp and provide opportunity for growth to larger and more marketable sizes."

Scientific Trivia: Dissolve Oxygen concentrations in water goes DOWN as Water Temperatures go UP!

Jim...
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Oops shrimp are born and grow in the DEAD ZONE.;)
I think you need to study the overlay of the closed areas with the dead zone a bit more :). And remember the dead zone is at depth, if something can swim to the near surface they can find oxygenated water.

More scientific trivia: Dissolved oxygen levels in open water do not fall below 2ppm by temperature, it requires BOD activity, in this case rotting algae.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
do not fall below 2ppm by temperature
Well... not so much.
You must include PRESSURE [Depth] and in "open water" the bottom temperatures.
Guess what loves low DO?
Red Fish, Drum, Catfish, Crab... etc. They love juvenile shrimp.

We can all agree the...
DEAD ZONE

Its not so dead, happens seasonally, sea life abounds, and continues to supply Commercial and Sportsman a great source of food and fun from our oceans. :stir:

And...

WE need to keep protecting our Oceans.:clap:
Jim...
 
  • Like
Likes: Rick486
Jun 21, 2004
2,897
Beneteau 343 Slidell, LA
Never the less, there are usually large fish kills annually that are associated with the so called "dead zone." Primarily manhadden. I don't believe that game fish and recreational fin fish ( reds & specks) are much affected, shrimp neither. Happens every year; don't think there is much that can be done locally as the run off from the entire MS River Valley empties into the GOM. Dolphin deaths are still at abnormally high levels since the oil spill. As Jim stated, we need to protect our coasts & oceans.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Menhaden are an essential feeder fish. When we stopped the overfishing of menhaden by the fish oil industry in the Bay and offshore the population of rockfish and other larger predator fish shot up. We are even seeing porpoises in the upper Chesapeake. Menhaden are candy to porpoises.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
7,770
Hunter 430 Waveland, MS
Menhaden are an essential feeder fish.
We call them "Pogey or Pogy" down here. This is a commercial fish that is harvested like shrimp [a herbivore] on the Gulf Coast. [Cat food, fish oils, fish meal, bait fish, etc.] The Pogey Boats are mini-fish processing plants that waste nothing on harvesting these LOW DO and Herbivore fish that eat Dead Zone algae, just like Carp.

Ain't Nature Wonderful?:clap:

We recently had a "fish kill". In my Opinion, a badly used term.

About 3 weeks ago the sportsman were out by the droves. What they call "BAIT" abounded in the Gulf Waters. When we were sailing, you can see the Shrimp so thick swirling and running at the surface to avoid the Carnivores, [that we all love to normally eat]. Pelicans, Gulls, Dolphin were feasting. If we would have held a fish net in the water, we could have caught more than we could eat for supper, just by sailing through the shrimp.

Then a few days later, dead shrimp and pogey, wash ashore along a few spot on public beaches.
OMG a FISH KILL? What did MAN do? The "knee jerk" reaction.

IMHO opinion too much BAIT, not enough food for them [and of course my boat killed some:rolleyes:]

The key to most life cycles is really the PLANKTON which are the Solar Collector of our Oceans. Plankton include algae and even jellyfish. They love to consume CO2 at times and O2 too in the Photosynthesis cycle

Thus RED ALGAE FISH KILLS. (pssttt there are green algae fish kills too:shhh:) but NOT Carp family fish.

Jim...

PS: Fish die of old age, disease, wounds, fright too.
 
Mar 20, 2011
623
Hunter 31_83-87 New Orleans
Just a thought. Didn't they open the Norco and the Morganza spillways last year and could that have led to the record area?