So are you asking for $250 to interview sharks at the surface to see if they are lost? I might just pony up the $250 if I get to video the interview :bonk:
Otter
Hypothesis on Poor Vis and GW's
- Thread starter drbill
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So are you asking for $250 to interview sharks at the surface to see if they are lost? I might just pony up the $250 if I get to video the interview :bonk:
Otter
I think the interview should explore not only if they are lost but also if they are hungry, and maybe also mad about being lost, hungry and having to dive in crappy viz.
OP
Red tide does not seem to be affecting us much here on Catalina although some reported a possible red tide north of Long Point. We're just getting a strong bloom, but will have to do a plankton tow to see what the species composition is at Catalina.
Did hear from John Moore in San Diego that there may be a "new" species of dinoflagellate involved.
Of course I'll keep diving and hoping I find a break in the soup.
Dr. Bill
Did hear from John Moore in San Diego that there may be a "new" species of dinoflagellate involved.
Of course I'll keep diving and hoping I find a break in the soup.
Dr. Bill
Frank O
Contributor
For what it's worth, about a week ago I asked an ocean scientist friend who studies ocean temperatures why he thought we were having such an unusual year. His response is below. (This doesn't address the shark issue.)
It sounds as though his discussion of warming/cooling this summer squares generally with Bill's comment that started this thread. As you can see, he is fairly pessimistic for the outlook later this fall.
However, I'm having a bit of a hard time squaring this explanation with my experience in a normal year. In most years, upwelling from Santa Ana Wind conditions in the fall actually bring up unusually clear water, and this can be some of the finest diving of the entire year. Cold water in winter generally means pretty nice vis, as long as you dodge the storms. Then when water _warms_ in spring, we get the plankton bloom, which usually lasts from late March or April through June. Anyway, I guess we all have to stay tuned ...
Forwarded:
Since we switched to the negative phase of the Pacific Decadal Oscillation in 1998, the winds from the north have been stronger, causing more upwelling, more nutrients, more plankton, more fish (cold water types), and cooler coastal temps .... except for the last two months, when the high pressure system in SW has weakened winds and caused temporary warming of coastal waters. Now northerly winds are back, and ocean (and land) temps are dropping. With Santa Ana season coming up in late-Sept and Nov, this should continue to cool off ocean and make it more green/goopy.
For sea surface temperatures, go to:
http://www.nodc.noaa.gov/dsdt/wtg12.html
Winds from the north cause the water to move offshore (upwell). This is due to the Coriolis force that moves water to the right of the wind direction.
It sounds as though his discussion of warming/cooling this summer squares generally with Bill's comment that started this thread. As you can see, he is fairly pessimistic for the outlook later this fall.
However, I'm having a bit of a hard time squaring this explanation with my experience in a normal year. In most years, upwelling from Santa Ana Wind conditions in the fall actually bring up unusually clear water, and this can be some of the finest diving of the entire year. Cold water in winter generally means pretty nice vis, as long as you dodge the storms. Then when water _warms_ in spring, we get the plankton bloom, which usually lasts from late March or April through June. Anyway, I guess we all have to stay tuned ...
Forwarded:
Since we switched to the negative phase of the Pacific Decadal Oscillation in 1998, the winds from the north have been stronger, causing more upwelling, more nutrients, more plankton, more fish (cold water types), and cooler coastal temps .... except for the last two months, when the high pressure system in SW has weakened winds and caused temporary warming of coastal waters. Now northerly winds are back, and ocean (and land) temps are dropping. With Santa Ana season coming up in late-Sept and Nov, this should continue to cool off ocean and make it more green/goopy.
For sea surface temperatures, go to:
http://www.nodc.noaa.gov/dsdt/wtg12.html
Winds from the north cause the water to move offshore (upwell). This is due to the Coriolis force that moves water to the right of the wind direction.
OP
FrankO- Cold water contains more nutrients than warm water which may be seriously depleted and unsuitable for algal growth. This is the relationship (inverse temp/nutrients) that your friend is correctly referring to.
He also mentioned the decadal cycle of cooling and warming. Although I'm not current on this, my latest understanding is that we're looking at a period of 23-26 years of warming and cooling. Prior to the 1977 El Nino temperatures were colder in this region and kelp much more luxuriant, especially in the warmest waters of Catalina from Long Point to the East End (in which Casino Pt. is located).
The other factor of significance is daylength. Days have been shortening in length of daylight since late June and this should also affect algal growth.
Either the situation improves or I'm off to the tropics for the fall, winter and spring!
Dr. Bill
He also mentioned the decadal cycle of cooling and warming. Although I'm not current on this, my latest understanding is that we're looking at a period of 23-26 years of warming and cooling. Prior to the 1977 El Nino temperatures were colder in this region and kelp much more luxuriant, especially in the warmest waters of Catalina from Long Point to the East End (in which Casino Pt. is located).
The other factor of significance is daylength. Days have been shortening in length of daylight since late June and this should also affect algal growth.
Either the situation improves or I'm off to the tropics for the fall, winter and spring!
Dr. Bill
Frank O
Contributor
Good point about the day length -- quite apart from water temp, I've always heard that that's a significant factor driving the bloom each spring.
I guess what I'm trying to square is this. I understand from you and my remote-sensing friend that cold water typically contains more nutrients, which can drive a bloom. And my friend's point being that a major cause of the current bloom is the upwelling of cold, nutrient-rich water. But then why is it that in most years divers exult at the arrival of Santa Ana Wind conditions in the late fall, which I usually hear described as bring the upwelling of cold, clear water? Is there a time lag issue involved here -- is it that the water is indeed clear right when the upwelling occurs, but over a period of time as little critters near the surface start their repast the water subsequently clouds up? Or is it just that by that point in the year, day length doesn't support a lot of bloom? Thanks for shedding any light on this point.
I guess what I'm trying to square is this. I understand from you and my remote-sensing friend that cold water typically contains more nutrients, which can drive a bloom. And my friend's point being that a major cause of the current bloom is the upwelling of cold, nutrient-rich water. But then why is it that in most years divers exult at the arrival of Santa Ana Wind conditions in the late fall, which I usually hear described as bring the upwelling of cold, clear water? Is there a time lag issue involved here -- is it that the water is indeed clear right when the upwelling occurs, but over a period of time as little critters near the surface start their repast the water subsequently clouds up? Or is it just that by that point in the year, day length doesn't support a lot of bloom? Thanks for shedding any light on this point.
OP
FrankO- Can't address the question re: clear water upselled during Santa Ana's. The lack of plankton blooms could be due to shorter daylengths in fall. We don't really experience much true upwelling here on Catalina like areas on the mainland coast.
Dr. Bill
Dr. Bill
Frank O
Contributor
Dr Bill, okay, thanks. Let's hope that upwelling + day length is the anomalous combination this year, and that as the days get shorter my friend's pessimism will prove to be unfounded!
If thats the case, I am outta here! =-)
OP
Otter- No need to worry. The decadal cooling that many believe we have entered should bring good diving. I remember conditions off Catalina from 1969-1976 being pretty good. Very rich kelp forests in our warmest sites. Not necessarily extended pea soup conditions.
I haven't been in since Sunday. My buddy Andrea and I are heading back over tonight for a weekend of diving, but may have to go out on one of the local LDS dive boats to find some vis since she's bringing her photo gear. East and west quarries were good last weekend.
Dr. Bill
I haven't been in since Sunday. My buddy Andrea and I are heading back over tonight for a weekend of diving, but may have to go out on one of the local LDS dive boats to find some vis since she's bringing her photo gear. East and west quarries were good last weekend.
Dr. Bill
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