From In Situ to satellite observations of pelagic Sargassum distribution and aggregation in the Tropical North Atlantic Ocean

The present study reports on observations carried out in the Tropical North Atlantic in summer and autumn 2017, documenting Sargassum aggregations using both ship-deck observations and satellite sensor observations at three resolutions (MSI-10 m, OLCI-300 m, VIIRS-750 m and MODIS-1 km). Both dataset...

Full description

Saved in:
Bibliographic Details
Published in:PloS one 2019-09, Vol.14 (9), p.e0222584-e0222584
Main Authors: Ody, Anouck, Thibaut, Thierry, Berline, Léo, Changeux, Thomas, André, Jean-Michel, Chevalier, Cristèle, Blanfuné, Aurélie, Blanchot, Jean, Ruitton, Sandrine, Stiger-Pouvreau, Valérie, Connan, Solène, Grelet, Jacques, Aurelle, Didier, Guéné, Mathilde, Bataille, Hubert, Bachelier, Céline, Guillemain, Dorian, Schmidt, Natascha, Fauvelle, Vincent, Guasco, Sophie, Ménard, Frédéric
Format: Article
Language:English
Subjects:
Agglomeration
Airborne observation
Atlantic Ocean
Biodiversity and Ecology
Biology and Life Sciences
Biomass
Brazil
Cloud cover
Coasts
Datasets
Earth Sciences
Ecology and Environmental Sciences
Ecology, environment
Ecosystems
Engineering and Technology
Environmental Sciences
Image resolution
Internet
Life Sciences
Measuring instruments
MODIS
Oceans
Physical Sciences
Rafts
Remote sensing
Sargassum
Sargassum (Seaweed)
Sargassum - growth & development
Satellite imagery
Satellite Imagery - methods
Satellite observation
Satellites
Seasons
Sensors
Ship decks
Ships
Summer
Typology
West Indies
Windrows
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The present study reports on observations carried out in the Tropical North Atlantic in summer and autumn 2017, documenting Sargassum aggregations using both ship-deck observations and satellite sensor observations at three resolutions (MSI-10 m, OLCI-300 m, VIIRS-750 m and MODIS-1 km). Both datasets reported that in summer, Sargassum aggregations were mainly observed off Brazil and near the Caribbean Islands, while they accumulated near the African coast in autumn. Based on in situ observations, we propose a five-class typology allowing standardisation of the description of in situ Sargassum raft shapes and sizes. The most commonly observed Sargassum raft type was windrows, but large rafts composed of a quasi-circular patch hundreds of meters wide were also observed. Satellite imagery showed that these rafts formed larger Sargassum aggregations over a wide range of scales, with smaller aggregations (of tens of m2 area) nested within larger ones (of hundreds of km2). Match-ups between different satellite sensors and in situ observations were limited for this dataset, mainly because of high cloud cover during the periods of observation. Nevertheless, comparisons between the two datasets showed that satellite sensors successfully detected Sargassum abundance and aggregation patterns consistent with in situ observations. MODIS and VIIRS sensors were better suited to describing the Sargassum aggregation distribution and dynamics at Atlantic scale, while the new sensors, OLCI and MSI, proved their ability to detect Sargassum aggregations and to describe their (sub-) mesoscale nested structure. The high variability in raft shape, size, thickness, depth and biomass density observed in situ means that caution is called for when using satellite maps of Sargassum distribution and biomass estimation. Improvements would require additional in situ and airborne observations or very high-resolution satellite imagery.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0222584