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Dr. Amy Siuda, Sea Education AssociationNASA/Sargasso Sea Commission Workshop/Meeting - 21 March 2016
Field Observations of Pelagic Sargassum
Sargassum Research Themes
• Concentration/Distribution/Circulation– geographic patterns– temporal patterns– aggregation/dispersion patterns
• Community Ecology– composition: abundance, richness, diversity
• between Sargassum forms• between regions • with Sargassum age• with Sargassum clump size/structure
– connectivity between populations
• 6-week SEA Semester cruises
• annually-repeated tracks
• data collected by > 7500 undergraduates 90
oW 80
oW 70
oW 60
oW 50
oW
5oN
10oN
15oN
20oN
25oN
30oN
35oN
40oN
45oN
50oN
Shipboard Pelagic Sargassum Sampling
WINTER
SPRING
SUMMER
FALL
Neuston Net1m x 0.5m
335µm mesh
Tow1 nm @ 2 knots
2x a day
Shipboard Pelagic Sargassum Sampling
Shipboard Pelagic Sargassum Sampling
Sargassum (g m-2)1992 to 2015
6985 tows
56% w/ Sarg.
Sargassum natans Sargassum fluitans
Sargassum: Two Pelagic Species
S. natans
S. fluitans
Sargassum Species Dominance (Sn-Sf)
Frequency of Aggregation Patterns
Visual Obs.
Near-Earth Pelagic Sargassum Observation
Near-Earth Pelagic Sargassum Observation
Recent Caribbean Inundations
2011 samples
2014 samples
S. natans-I S. fluitans-III S. natans-VIII
Pelagic Sargassum: 2 Species, Many Forms
Thorns on stem
absent present absent
Spines on float (scale = 5mm)
present absent rare
Blade Shape and Size (scale = 5mm)
long, narrow short, wide long, wide
(Parr,1939)
S. natans-I S. fluitans-ssp. S. natans-VIII
S. natans-I S. fluitans-ssp. S. natans-VIII
3 Common Forms, Distinct Distributions
Schell et al. 2015 Oceanography
Caribbean Disconnected from Sargasso Sea
Schell et al. 2015 Oceanography
Windrows of Sargassum fragments
Dense Sargassum mat composed of
large branching clumps
Long-
term
30x
Long-
term
300x
Long-
term
November 2014 v. 2015 Observations
Columbus crab
bryozoans
sea anemones
hydroids
Sargassum Community - Sessile
nudibranchs
crabs fishes
Sargassum Community - Mobile
snails
shrimp
Detailed Clump/Fauna Analysis
• Caribbean– Total: 6 species
– Unique: 1 species
• Gulf of Mexico– Total: 15 species
– Unique: 9 species (mostly fish)
• Sargasso Sea– Total: 12 species
– Unique: 5 unique
Sargassum Community - Sessile
Martin 2015
Collaborators: Lesley-Ann Dupigny-Giroux (UVM)
Deborah Goodwin (SEA)
John Hanning (Archimedes Aerospace)
Darren Hitt (UVM / VT Space Grant)
Lindsay Martin (TAMU)
Jeffrey Schell (SEA)
Robbie Smith (BAMZ)
Funding: Sea Education Association
University of Vermont
IUCN and Sargasso Sea Alliance
National Science Foundation
New England Aquarium
Marine Conservation Action Fund
Solvin Zankl