[Coral-List] Cold water upwelling- Florida

[John Reed]

Re: Cold water upwelling- Eastern Florida

[Sorry- my previous email incorrectly reported temp of 50C- I meant 50F]

In addition to the cold upwelling described by Dr. Alina Szmant's excellent
papers on
the Florida Keys, upwelling is also a major factor off central eastern
Florida from Cape Canaveral to Palm Beach.

We just finished one of the coldest and longest periods of intense upwelling
here since I started my studies in this area in 1976.  Divers reported
bottom temperatures of 50F (10C) (and one report of 48F) at the 30',60', 90'
reefs.  Typical bottom temperature on the shallow reefs here is 80+F in the
summer with periodic 1-2 week periods of upwelling from June to August.
Usually the upwelling produces bottom temperatures around 60 or upper 50s.
This year's event right during lobster mini season caused extensive death of
spotted moray eels and stunned snapper and grouper.

In deeper water of the this same region, the deep-water Oculina reefs have
periodic upwelling events every 4-6 weeks throughout the year (Reed 1981,
Smith 1981, Reed 1983, summarized in Reed 2002).  Long term thermographs and
current meters placed at the base of an Oculina bank (80 m) showed an
average bottom temperature of 16.2C (61F) and ranged from 7.4C (45F) to
26.7C (80F).
During upwelling events the temperature would drop below 10C (50F); also
levels of nutrients and chlorophyll increased nearly an order of magnitude:
nitrates from <2 uM during non-upwelling to 9-18 uM during upwelling;
phosphate from <0.25 to 0.5-2.0 uM; and Chlorophyll-a from <1 to 1-9 mg m3
(Reed, 1983; Reed 2002).

Reed, J. K.  2002.  Deep-water Oculina coral reefs of Florida: biology,
impacts, and management.  Hydrobiologia 471: 43-55.  

Reed, J.K.  1983.  Nearshore and shelf-edge Oculina coral reefs:  The
effects of upwelling on coral growth and on the associated faunal
communities.  Pp. 119-124, In: M. Reaka (ed.), The ecology of deep and
shallow coral reefs, Symposia Series for Undersea Research, Vol. 1, NOAA.

Reed, J.K.  1981.  In situ growth rates of the scleractinian coral Oculina
varicosa occurring with zooxanthellae on 6-m reefs and without on 80-m
banks.  Pp. 201-206, In: Proceedings Fourth International Coral Reef
Symposium, Vol. 2,  May 1981, Manila, Philippines.

Smith, N.P. 1981.  An investigation of seasonal upwelling along the Atlantic
coast of Florida. Proc. 12th Internat. Liege Colloque Ocean Hydrodynamics:
79-98.

Regards,
John Reed
Senior Research Specialist
Division of Biomedical Marine Research
Harbor Branch Oceanographic Institution
5600 U.S. 1 North, Fort Pierce, FL 34946
Phone- 772.465.2400 ext. 205
Fax- 772.461.2221
Email- jreed at hboi.edu