Published on: September 29, 2026
NOAA and partners successfully completed their eighteenth PIRATA Northeast Extension cruise in support of a key tropical Atlantic observing system. Aboard NOAA Ship Pisces, a new ship for this science mission, scientists spent nearly a month at sea traveling from the Canary Islands to Barbados conducting various research efforts along the way. Their journey was leg 2 of the broader PIRATA Northeast Extension cruise which took place in two separate legs over the span of two months.
Researchers from NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) completed 67 CTD (Conductivity, Temperature, Depth, oxygen concentration, and currents) casts collecting data from the ocean’s surface to about a mile deep, and deployed 8 profiling floats and 11 surface drifters. Partners from Woods Hole Oceanographic Institution (WHOI) collected Sargassum and nutrient samples, and a team from Virginia Union University measured aerosols and atmospheric chemistry.
PIRATA (Prediction and Research Moored Array in the Tropical Atlantic) is a collaborative project between Brazil, France, and the United States that uses moorings to study and improve the predictability of air-sea interactions in the tropical Atlantic Ocean. Air-sea interactions have a large impact on weather and climate variability and can be a determining factor in the prediction of extreme weather and ocean changes. In the tropical Atlantic, these interactions influence development of droughts, floods, marine heat waves, severe tropical storms and hurricanes, and fisheries landings, with direct impacts in the Americas and Africa.
PIRATA Northeast Extension (PNE) is a joint project between NOAA’s AOML and Pacific Marine Environmental Laboratory (PMEL) that expands the PIRATA array of moored buoys into the northern and northeastern sectors of the tropical Atlantic Ocean. It is important to collect measurements in this part of the ocean because this is the main development region for Atlantic hurricanes.
In support of the PNE project, the team conducted 67 CTD casts along their route to collect ocean data across the tropical Atlantic. CTD devices give scientists a detailed look into the properties of the water column by detecting how the salinity and temperature of the water change relative to depth. The CTD rosette was augmented by total dissolved oxygen and Lowered Acoustic Doppler Current Profilers to also measure oxygen and velocity.
Additionally, scientists and crew deployed 7 Argo floats provided by WHOI, 1 ALAMO (Air-Launched Autonomous Micro Observer) float, and 11 surface drifters at various locations along the cruise track. Argo floats complete a profile every 10 days, collecting temperature and salinity ocean data from the surface to 1.2 miles deep, while ALAMO floats profile more rapidly (every 8 hours) to a depth of about a half of a mile. Drifters float at the ocean’s surface collecting ocean surface temperature and sea level pressure data while also helping scientists understand ocean currents. Unlike CTD casts which only capture a moment in time, floats and drifters remain out at sea collecting data for more than a year. These ocean observing instruments are deployed throughout the global ocean and help to improve weather forecasts and advance our knowledge of climate fluctuations.
“Everything went very smoothly on our first PNE cruise aboard the Pisces. We accomplished all of our science objectives and had time to collect additional Sargassum and upper-ocean water samples, thanks to efficient CTD operations and the flexibility of the Pisces’ crew and officers. The unique data acquired during the cruise will help us understand and predict weather and ecosystems throughout the tropical Atlantic and downstream in the Caribbean and the southeastern U.S.,” said Greg Foltz, PhD, AOML oceanographer and Chief Scientist on the cruise.
Researchers from WHOI joined the PNE cruise for the third time to conduct Sargassum sampling in support of various Sargassum research projects.
WHOI scientists are investigating the changing chemical balance inside Sargassum over time to see if changes in nutrient supply in the ocean are fueling Sargassum blooms. When Sargassum was spotted along the cruise track, a physical sample was obtained and surface water samples were collected for nutrient analysis. On average, WHOI collected 9 samples at each location, drying them for later analysis.
Sargassum is a type of floating brown alga, commonly called “seaweed,” that floats at the sea surface, where it can aggregate to form large mats in the open ocean. Historically, the majority of Sargassum grew and lived in the Sargasso Sea in an area of the western North Atlantic Ocean. In 2011, the geographic range of Sargassum expanded, and massive amounts appeared in the Tropical Atlantic, creating the Great Atlantic Sargassum Belt which stretches from the coast of West Africa to the Caribbean Sea and Southeast U.S.
Although Sargassum provides habitat, food, protection, and breeding grounds for hundreds of diverse marine species, the sudden overgrowth has led to unprecedented mass beaching events which can disrupt coastal ecosystems as well as shipping, tourism, and fishing industries. Collecting Sargassum samples helps researchers to understand the environmental conditions that affect Sargassum growth, its species diversity, and how its spatial distribution and abundance change over time.
“This partnership with NOAA has provided an outstanding opportunity to sample Sargassum in what appears to be one of the initiation zones for the Great Atlantic Sargassum Belt. We are deeply grateful for this collaboration with the PNE team” said Dennis McGillicuddy, PhD, a scientist at the Woods Hole Oceanographic Institution.
Additionally, there were two participants from the AEROSE Team represented by Virginia Union University (VUU) aboard the cruise to measure aerosols and atmospheric chemistry. AEROSE stands for the Saharan Dust Aerosols and Ocean Science Expeditions. It is a series of transatlantic field campaigns to explore African air mass outflows and their impacts on climate, weather, and environmental health.
During the expedition, the VUU team deployed several atmospheric monitoring instruments: an ozone analyzer for ozone concentrations, an Aerodynamic Particle Sizer (APS) for aerosol size distributions and human health impact data, and two Microtops II multi-band sun photometers to measure aerosol optical properties which provides information on aerosol concentration, particle size, and aerosol type. Special emphasis was placed on observing Saharan dust outbreaks, biomass burning aerosols, haze layers, and cirrus cloud conditions across a wide range of latitudes and longitudes.
To study transatlantic dust transport, dust samples were collected for lab analysis to determine particulate composition and correlate physical and chemical characteristics with APS data and potential health impacts. Additionally, over 200 ocean water samples were taken at PNE mooring locations to evaluate relationships between atmospheric dust deposition and marine environments.
Throughout the expedition, the VUU participants also provided daily meteorological briefings to the science team which included analyses of sea-state conditions, wind and wave characteristics, storm development, and four-day forecasts of atmospheric and oceanic conditions.
Occurring annually, the PIRATA Northeast Extension cruise provides a place for multiple research projects to take place at the same time. Traversing the tropical Atlantic Ocean over the course of a month offers an unique opportunity to deploy instrumentation, gather data and collect samples from remote regions. Researchers take advantage of this valuable platform to advance their science missions.
This cruise is funded by NOAA’s Global Ocean Monitoring and Observing (GOMO), with personnel and equipment support from NOAA’s AOML, NOAA’s PMEL, and University and Cooperative Institute partners.
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