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