BIO 469 Lecture 21: Sargasso Sea
13 Jun 2018
School
Department
Course
Professor
Sargasso Sea
Key spatial and temporal dimensions:
● Vast spatial scale of the distribution of the animals and the seaweed
● The intimate scale of life within a clump or mat of Sargassum weed
○ Animals may spend their entire life within 1 square meter
● Temporal scales of distribution and oceanographic processes
○ Migratory animals use the Sargasso Sea on a seasonal basis
○ Mass migration of plankton and fishes from deep water into the shallow surface
waters each night
Interacting patterns of water movement
● Prevailing current systems in the N Atlantic formed a grye that retains floating
Sargassum forming the “Sargasso Sea”
○ John Ryther
● Are there any patterns in the distribution of Sargassum within the Sargasso Sea and
how many different species are associated with Sargassum ?
Spatial Distribution of Sargassum
● A great challenge of studying Sargassum is knowing where it is and if there are
conditions or factors that have variable influence on the plants (ex. Water temp, day
length) , the associated animals or key processes, according to latitude or longitude
What does Sargassum look like at sea?
How does this influence our ability to measure its occurrence?
● Long “windrows” formed by wind and subsurface currents
● Buoyant
● Large mats can form under low winds, when windrows begin to aggregate mats can be
5-20 metres across
○ Marine turtles spend time in Sargassum
■ Security from bottom + air
Bloom
● Caribbean bloom in 2011
● Temporally very abundant if conditions favor it
● Very few organisms eat sargassum, brown algae
Measuring Sargassum
● Towing a surface neuston net for about 1 nautical mile
○ Can have a bias by either cutting across windrows or by following along a
windrow
● BIOS had long term study around 1971-1976 by Jim Butler and Bryon Morris
● Alan Stoner from SEA began sampling in 1977 and the SEA continues to do this work
nearly 40 years of continuous effort
○ Shows more sargassum to the N Sargasso Sea in Fall; more to the SW
Sargasso in the spring
○ Maybe due to faster growth in lower latitudes early in the year, followed by re-
distribution by hurricanes and subsequent growth at higher latitudes in the late
summer
● More study
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Vast spatial scale of the distribution of the animals and the seaweed. The intimate scale of life within a clump or mat of sargassum weed. Animals may spend their entire life within 1 square meter. Temporal scales of distribution and oceanographic processes. Migratory animals use the sargasso sea on a seasonal basis. Mass migration of plankton and fishes from deep water into the shallow surface waters each night. Prevailing current systems in the n atlantic formed a grye that retains floating. A great challenge of studying sargassum is knowing where it is and if there are conditions or factors that have variable influence on the plants (ex. Water temp, day length) , the associated animals or key processes, according to latitude or longitude. Long windrows formed by wind and subsurface currents. Large mats can form under low winds, when windrows begin to aggregate mats can be. Temporally very abundant if conditions favor it. Very few organisms eat sargassum, brown algae.
