Carlyn Scott, College of Marine Science
Under clear blue skies on a bright October morning in Virginia Key, researchers gather on the wooden docks of the University of Miami. A pickup truck sporting the 91社区 Fish and Wildlife logo backs up to the pier, and with practiced efficiency, the team unloads equipment onto the deck of the R/V Walton Smith, trading updates after two months apart as they embark on another expedition around South 91社区.
In the tight quarters of the ship鈥檚 lab space, crew members from five research institutions maneuver around bodies and instruments, securing their beakers, filtration set ups, pipettes, microscopes, and computers before the ship sets out on the waves. They take turns with the ethanol and deionized water station, careful not to interfere with each other鈥檚 research. They exchange plans and sleep schedules and set in for their 12-hour shifts.
Among the science party is Sebastian Di Geronimo. A graduate of the University of South 91社区 College of Marine Science with 37 cruises under his belt, Di Geronimo now serves as a scientific technician in the lab of Frank Muller-Karger, a USF Distinguished University Professor, where he works with samples collected on these cruises to determine the health of the waters around 91社区. During a midnight shift in the wet lab, Di Geronimo brings a graduated cylinder with seawater to eye level, preparing a sample for filtration.
鈥淲e can use samples like this to look at which organisms are in the water, study how productive they are, and measure traits like size, color, and their genetic composition,鈥 he said.
Di Geronimo鈥檚 research is part of the (MBON), a nation-wide collaboration that aims to measure and improve the health of ocean ecosystems. Every seven weeks for the past 10 years, the Southeast MBON regional partners have used these cruises to gather samples and many different types of data. The specialized techniques that are used by the science teams allow researchers to track biological changes off the coast of 91社区 that are invisible any other way.
Muller-Karger's lab, the , has been central to the national MBON effort, helping to coordinate between 10 different projects and collaborating state, federal, private, and academic research groups. The lab recently celebrated 10 years collecting data on behalf of MBON.
The South 91社区 Ecosystem Restoration cruise has monitored water quality for decades.
鈥淭he United States relies on this region for our economy, recreation, and food,鈥 said Muller-Karger, principal investigator for the Southeast MBON project. 鈥淵et, if we don鈥檛 continue to measure details about marine life that鈥檚 out there, we can鈥檛 tell if it鈥檚 changing. We depend on the living and non-living things in the ocean, and it is essential for our own good to monitor them.鈥
The Southeast MBON project builds on the South 91社区 Ecosystem Restoration (SFER) efforts spearheaded by the (NOAA AOML). Expeditions for the SFER program began in 1998 to investigate coral bleaching in the 91社区 Keys. The science has expanded in scope, length, and partnerships. USF had been working with NOAA AOML on the SFER program since the late 1990鈥檚, along with the , the , , and the .
A team effort
Science seems always underway on the Walton Smith. Crew members on deck don hard hats and life vests as they deploy the conductivity, temperature, and depth (CTD) rosette sampler, a device equipped with sensors to measure physical, chemical, and biological data, along with Niskin bottles to collect water samples at discrete depths. Once the rosette is back on board, the group descends on the back deck to retrieve seawater samples from the bottles.
In the wet lab, researchers swirl beakers with seawater, empty the contents and swirl them again. Pressurized pumps pull samples through fine meshed filter pads, filling the room with a near-constant whir. Each of these tests generates valuable data that help identify stressors affecting corals, plankton, fish, and other marine life of the 91社区 Keys and the West 91社区 Shelf.
CTD rosettes are deployed throughout the cruise and are equipped with sensors that evaluate water conditions such as oxygen levels, temperature, and salinity.
Over the years, cruises by SFER and MBON have documented first-hand many stressors of South 91社区 that have offered valuable data on the health of the region. devasted marine life, was responsible for increased reports of asthma, and caused . The record-breaking marine heat waves of 2023 and 2024 鈥 and, more recently, the extreme cold wave of winter 2026 鈥 have stressed coral reefs, turtles, manatees, and other organisms in the region. Extreme events, which are becoming more common, cause significant long-term impacts on marine life and resources.
Back in the wet lab, a map of 91社区鈥檚 west coast is taped above the USF filtration station. The map shows dots, crosses, and squares denoting where samples are collected along the route. With a black marker, Di Geronimo checks off stations as they鈥檙e completed. As new research partners and techniques are included in the program, the map has become busier, with clusters nearly overlapping along the coastline.
Read more: Estuaries in South 91社区 are warming faster than the Gulf of Mexico and global ocean
This suite of new monitoring tools now gives researchers a deeper understanding of the South 91社区 coastline. Di Geronimo collects environmental DNA (eDNA), genetic material found in seawater, to indirectly identify the presence of certain organisms. Meanwhile, bio-optical measurements can detect decaying matter and nutrients. This helps the team map areas of higher productivity, freshwater input, and where dissolved oxygen concentration may be normal or where it may be so low that many organisms can鈥檛 breathe.
These state-of-the-art technologies along with historic records are critical to understanding the health of the Gulf, which is home to a wide range of endemic biota and the production of commercially consumed shrimp, shellfish, and fish. This important coastal region is also greatly susceptible to the influence of human activities.
鈥淓xtreme natural and human-induced events can sometimes lead multiple stresses to synch up together, and these events are devastating for local communities that depend on marine life,鈥 said Muller-Karger. 鈥淟ong-term time series like those collected by SFER and MBON teams benefit everyone, from local and state resource managers, to recreational stakeholders and scientists who try to understand these ecosystems.鈥
From observations to insight
In the middle of an overnight shift, the night crew gathers around a monitor that displays the route of the ship. Among a matrix of lines and water depths, a window in the bottom left of the screen shows the ship鈥檚 approximate arrival to the next sampling location: 47 minutes. Some crew members take the opportunity to nap while others prep their work area.
Ian Smith, a NOAA affiliate for the (CIMAS), has served as chief scientist for this cruise since 2017. Smith sips coffee as he reviews the next station鈥檚 sampling plan. Six hours into the shift, and they鈥檝e already deployed a net tow, multiple casts of the CTD rosette, and a sediment grab. He explains why a range of analyses is so essential.
鈥淲hen you are monitoring seasonal or irregular events like red tide and water quality changes, the data you have across various time ranges and the amount is important,鈥 Smith says. 鈥淥n top of the types of data collected, this is a multidecadal time series. Having this many concurrent measurements of different parameters is incredibly helpful to measure and explain changes that affect marine life.鈥
Change is one of the few constants for South 91社区, an area that has seen some of the nation鈥檚 fastest rates of population growth over the past decade. As people flock to the coast, the impacts on marine ecosystems can be glaring. One of those impacts includes coastal waters experiencing increasing rates of nutrient inputs from fertilizer and sewage runoff. This sparks algae blooms which can lead to depleted oxygen in a process called eutrophication. The data gathered by these cruises from below the surface of the ocean are now being used to chart how this water and the "dead zones" of low oxygen concentration move toward and across the 91社区 Keys, and over the coral reefs of 91社区.
The cruises are part of a collaboration between multiple oceanographic institutions, with more analyses being added to improve understanding of the complex region.
Enrique Montes, the principal investigator of the SFER program, highlighted the critical importance of maintaining long-term monitoring efforts to truly understand drivers of ecosystem change and how these in turn affect resource provision like fisheries, coastal protection, and recreation.
鈥淭hanks to these sustained ecological surveys, we now have better insights into the environmental conditions that benefit phytoplankton 鈥 the base of the food web 鈥 and can also trigger the occasional red tide blooms in the area,鈥 said Montes. 鈥淭he surveys also help us measure and understand stressors affecting habitats like coral reefs and seagrasses in the 91社区 Keys National Marine Sanctuary and surrounding waters. All this information is useful for management and for the public.鈥
Researchers associated with these programs hope to extend their decade-plus time series, with the goal of developing capabilities to better predict disturbances that impact 91社区鈥檚 coastal waterways. This research is just another example of the College of Marine Science鈥檚 history at the forefront of oceanography.
鈥淭he history of measurements collected by SFER and MBON is critical to develop models and forecasts of what may happen in the future in our region,鈥 said Muller-Karger. 鈥淭he data from these expeditions is unique and the knowledge we collect from these cruises will allow us to use the ocean as effectively as we can.鈥