Hi Art.
 
     While I have given my copy to my aspiring oceanographer son and can't
     give you a perfect reference, I'll refer you to a discrete chapter in
     Joel Hedgepeth [ed.], 1957(?).  Treatise on Marine Ecology and
     Paleoecology. Vol.1, Ecology.  Memoirs of the Geological Society of
     America. >1,000p.
 
     The questions and discussions on conch-l suggest that you and others
     are fairly unfamiliar with this well-studied, and
     taxonomically-well-defined ecosystem.
 
     This chapter (I've forgotten the author's name) is one of the
     classical descriptions of the pelagic Sargassum ecosystem.  Here,
     Sargassum ("Gulf weed") plays a role as a dominant plant genus (two
     main species in the Atlantic; S. natans, S. fluitans) supporting a
     predictable assemblage of invertebrates and fishes.  Sargassum is a
     floating brown macroalga (phaeophycophyta) and has nothing whatever to
     do with the microscopic dinoflagellates that can bloom in coastal
     waters, killing fishes.
 
     Sargassum is rather analagous to seagrass beds and mangrove forests
     that support their own associated fauna and flora.  Among the dominant
     animals in the Sargassum community are shrimps, a portinid crab,
     amphipods, attached bryozoans and hydroids, juvenile sea turtles,
     snails, and fishes.  In some ways the brown alga serves as a "benthic"
     substrate in an otherwise pelagic environment.
 
     The Sargassum Sea is a fuzzily-delimited region in the anticyclonic
     gyre in the North Atlantic, the western boundary of which coincides
     with the Florida Current and the Gulf Stream.  The main
     characteristics of the "Sea" is its relative self containment and
     isolation, low planktonic productivity and incredibly clear,
     cobalt-blue water (among the clearest in the world -- you can see a
     dime thrown overboard forever, it seems.) Salinity and temperature are
     pretty normal for the pelagic environment and they're definitely
     non-problems and not limiting factors in themselves.  The floating
     Sargassun serves as a sort of oasis of life in a biological desert.
     For this reason, there are a number of questions regarding the flow of
     energy, nutrients, carbon, and nitrogen into, passed through, and
     exported out of the system.  We do know that the Sargassum that dies
     and finally sinks into the deep sea can provide a significant source
     of energy to places like the Hatteras Abyssal Plain in about 5,000m of
     water.
 
     During storms, and through the action of certain spin-off eddies, lots
     of Sargassum can be entrained into shallow continental shelf habitats
     and then found stranded on the beach.  There are few better ways of
     teaching kids neat biology than letting them sort through fresh
     seaweed for living critters.
 
     Also try looking up "Sargassum" on the net.
 
     Robert M. Avent
     Oceanographer
     Minerals Management Service
     New Orleans, LA
     504-736-2899
 
     ps
 
     Oh -- and there's absolutely nothing to the "Bermuda Triangle" that
     can't be attributed to natural phenomena and local conditions.  There
     are no really unusual magnetic anomalies, ancient cities, sea monsters
     or little green alien dudes.  Sorry, shellers.
 
     Bob
 
 
______________________________ Reply Separator _________________________________
Subject: More on Sargasso Sea -Reply
Author:  MR ART WEIL <[log in to unmask]> at ~smtp
Date:    5/21/98 9:52 PM
 
 
Paul;-
   That's a very fine answer about Sargassum and Red Tide. Is the red
algae poisonous to mollusks that injest it?  Again, is the sargassum
home to small shrimp and crabs? Does the sargassum itself act as a
buffer to waves and movement or does it just exist in this quiet zone?
 Are there other such zones in other oceans similar to this?
      Art