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Untreated sewage and fertilizer runoff threaten the Florida manatee’s main food source, contributing to malnutrition
Aarin-Conrad Allen, Florida International University
The gentle, slow-moving Florida manatee has no natural predators.
And yet, these charismatic mammals face numerous threats.
Manatees are struck by vessels in busy waterways across the state, and a majority bear scars from these collisions.
Harmful algal blooms – characterized by the rapid growth of algae that degrades water quality – can impair their nervous systems.
With less blubber, or fat, compared with other marine mammals like whales, dolphins, seals and sea lions, manatees are vulnerable to cold-stress syndrome during winter months.
And they can ingest or get entangled in marine debris like derelict fishing gear and drown or be crushed by floodgate and water control structures.
I am a doctoral candidate in marine biology at Florida International University’s Institute of Environment. Over the past 15 years, I have gained extensive experience working with marine mammals, particularly manatees.
Recently, my colleagues at the United States Geological Survey, Florida Department of Environmental Protection and I documented a change in the dietary pattern of manatees. We found that manatees are eating less seagrass – traditionally their primary food source – and more algae than in decades past. This change occurred along Florida’s Atlantic coast during a period of extensive seagrass decline.
We believe this represents an emerging threat to the species’ survival.
Protected species
Manatees were listed as an endangered species under the Endangered Species Act of 1973. By the early 1990s, the manatee population in Florida had dwindled to less than 1,300.
Researchers believe that federal protection, along with additional state measures such as slow-speed zones and no-entry refuges, has contributed to the growth of the manatee population in Florida.
In 2017, manatees were reclassified from endangered to threatened. Surveyors counted 5,733 individual manatees during a statewide aerial survey conducted in 2019.
Florida manatees average 9-12 feet (2.7-3.7 meters) in length and typically weigh about 1,000 pounds (450 kilograms), but they can grow as large as 3,500 pounds (1,600 kilograms). As the largest fully aquatic herbivore, they consume 5% to 10% of their body weight in vegetation each day.
While manatees eat a broad diet of over 60 different plants, they most commonly feed on species of seagrass. Seagrasses are marine plants that, like land plants, have leaves, flowers, roots and seeds, and make their food through photosynthesis.
So what happens when these seagrasses are no longer available?
A changing estuary
The Indian River Lagoon is an estuary along Florida’s east coast that covers roughly 350 square miles (560 square kilometers) between the mainland and barrier islands, from Ponce Inlet to Jupiter Inlet.
It is a critical habitat for manatees, which feed on native seagrass meadows in the lagoon during their seasonal migrations.
Seagrasses are vital to the health of marine ecosystems. They are a habitat for juvenile fish and other marine organisms, provide food for aquatic herbivores, reduce carbon in the atmosphere and improve water quality. They also protect coastal habitats by stabilizing sediments and reducing wave energy that can erode shorelines and damage coastal infrastructure, especially during hurricanes.
For more than a decade, the Indian River Lagoon has experienced extensive loss of seagrass meadows, due to a series of algae blooms associated with nutrient runoff and degraded water quality from septic overflow leaching into the environment.
When untreated sewage and fertilizers flow into the estuary, they add nitrogen, phosphorus and other nutrients that drive excessive algal growth. These harmful algal blooms deplete oxygen levels and block sunlight, which seagrass needs for photosynthesis.
Between 2011 and 2019, over 50% of all seagrass in the lagoon was lost. This led to an increase in macroalgae and even led to a change in the animal communities that live in the lagoon. For example, among finfish, sheepshead populations declined, while seabream numbers increased. Invertebrate communities were also affected, with bryozoans colonizing areas previously dominated by barnacles.
Manatees along the Atlantic coast have suffered two unusual mortality events since the seagrass decline, including one that is ongoing. Researchers attribute the increase in manatee deaths to malnutrition due to a shortage of seagrasses in the Indian River Lagoon.
A shift in manatees’ diet
In our study, we examined 193 manatee stomach samples collected from carcasses recovered from the Indian River Lagoon during two time periods – one before and one after the onset of the seagrass loss in 2011.
We compared stomach sample contents from carcasses collected between 1977 and 1989 with samples collected between 2013 and 2015.
Our findings indicate that manatees consumed 45% less seagrass and 74% more algae after the seagrass decline.
Recently, in a study supported by FIU’s Center for Aquatic Chemistry and Environment, I investigated differences in the nutritional composition – like protein, fat, carbohydrate and fiber – of items identified in manatee stomach samples. My preliminary results show notable differences in the nutritional composition of seagrass and algae.
Marine mammals are particularly vulnerable to dietary shifts due to their large size and high energy demands. Such changes can worsen their physical health and increase the likelihood of starvation.
Depleted oxygen levels are having a similar impact on aquatic vegetation and seagrass meadows in other regions of Florida, like Biscayne Bay and the Caloosahatchee River and Estuary. This suggests that the ecological challenges seen in the Indian River Lagoon could become more widespread.
What is the solution?
Remediation efforts within the lagoon have incorporated the restoration of seagrass through aquaculture and replanting strategies, similar to efforts to restore coral reefs.
While the lagoon’s seagrass has recently shown signs of regrowth, the rehabilitation of the ecosystem must begin with improving and maintaining water quality.
Counties along the lagoon have enacted fertilizer bans that aim to reduce the levels of nitrogen and phosphorus in the water that drive algal blooms.
New research, however, indicates that these restrictions alone will not fix the problem, as residential septic systems are the primary source of nutrient pollution in the lagoon.
Furthermore, many of the factors contributing to harmful algal blooms are intensified by global warming and changing climate, which could accelerate the decline of seagrass in Florida and elsewhere.
Given the multiple, synergistic threats facing manatees, I believe that improving water quality, protecting their food sources, and further research – coupled with community outreach and education – are critical to ensure the long-term survival of this iconic Florida species.
Aarin-Conrad Allen, Ph.D. Candidate in Marine Sciences, Florida International University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Last Updated on April 12, 2026 by Daily News Staff
Today, we’re undertaking important site maintenance to improve the performance and user experience of the Sleeves SPR Store while completing the merger with STM-STORE.
This transition marks a key step in streamlining our online shopping experience—bringing all merchandise under one unified platform. Our goal is to deliver a faster, more reliable, and more seamless store for our community.
What to Expect During Maintenance
As we work through this upgrade and integration process, visitors may notice:
- Temporary downtime on both Sleeves SPR Store and STM-STORE
- Intermittent access interruptions
- Ongoing updates and improvements behind the scenes
We understand that downtime can be inconvenient, and we appreciate your patience as we complete these upgrades.
Staying Informed
We’ll continue to keep you updated on our progress and notify you as key milestones are reached. Our team is working to complete this transition as efficiently as possible while ensuring everything runs smoothly once fully launched.
Thank You for Your Support
We’re grateful for your continued support as we improve and grow. This merger represents an exciting step forward, and we look forward to delivering an enhanced shopping experience very soon.
Stay tuned for updates.
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Space and Tech
Jupiter’s moons hide giant subsurface oceans − Europa Clipper is one of 2 missions on their way to see if these moons could support life
NASA’s Europa Clipper and ESA’s JUICE missions aim to explore Jupiter’s icy moons, focusing on the potential habitability of their underground oceans, particularly Europa’s, by gathering vital scientific data.
Last Updated on April 11, 2026 by Daily News Staff
On Oct. 14, 2024, NASA launched a robotic spacecraft named Europa Clipper to Jupiter’s moons. Clipper will reach the ice-covered Jovian moon Europa in 2030 and spend several years collecting and sending valuable data on the moon’s potential habitability back to Earth.
Clipper isn’t the only mission highlighting researchers’ interest in Jupiter and its moons.
On April 13, 2023, the European Space Agency launched a rocket carrying a spacecraft destined for Jupiter. The Jupiter Icy Moons Explorer – or JUICE – will spend at least three years on Jupiter’s moons after it arrives in 2031.
I’m a planetary scientist who studies the structure and evolution of solid planets and moons in the solar system.
There are many reasons my colleagues and I are looking forward to getting the data that Europa Clipper and JUICE will hopefully be sending back to Earth in the 2030s. But perhaps the most exciting information will have to do with water. Three of Jupiter’s moons – Europa, Ganymede and Callisto – are home to large, underground oceans of liquid water that could support life.
Meet Io, Europa, Ganymede and Callisto
Jupiter has dozens of moons. Four of them in particular are of interest to planetary scientists.
Io, Europa, Ganymede and Callisto are, like Earth’s Moon, relatively large, spherical complex worlds. Two previous NASA missions have sent spacecraft to orbit the Jupiter system and collected data on these moons. The Galileo mission orbited Jupiter from 1995 to 2003 and led to geological discoveries on all four large moons. The Juno mission is still orbiting Jupiter today and has provided scientists with an unprecedented view into Jupiter’s composition, structure and space environment.
These missions and other observations revealed that Io, the closest of the four to its host planet, is abuzz with geological activity, including lava lakes, volcanic eruptions and tectonically formed mountains. But it is not home to large amounts of water.
Europa, Ganymede and Callisto, in contrast, have icy landscapes. Europa’s surface is a frozen wonderland with a young but complex history, possibly including icy analogs of plate tectonics and volcanoes. Ganymede, the largest moon in the entire solar system, is bigger than Mercury and has its own magnetic field generated internally from a liquid metal core. Callisto appears somewhat inert compared to the others, but serves as a valuable time capsule of an ancient past that is no longer accessible on the youthful surfaces of Europa and Io.
Most exciting of all: Europa, Ganymede and Callisto all almost certainly possess underground oceans of liquid water.
Ocean worlds
Europa, Ganymede and Callisto have chilly surfaces that are hundreds of degrees below zero. At these temperatures, ice behaves like solid rock.
But just like Earth, the deeper underground you go on these moons, the hotter it gets. Go down far enough and you eventually reach the temperature where ice melts into water. Exactly how far down this transition occurs on each of the moons is a subject of debate that scientists hope to resolve with JUICE and Europa Clipper. While the exact depths are still uncertain, scientists are confident that these oceans exist.
The best evidence of these oceans comes from Jupiter’s magnetic field. Saltwater is electrically conductive. So as these moons travel through Jupiter’s magnetic field, they generate a secondary, smaller magnetic field that signals to researchers the presence of an underground ocean. Using this technique, planetary scientists have been able to show that the three moons contain underground oceans. And these oceans are not small – Europa’s ocean alone might have more than double the water of all of Earth’s oceans combined.
An obvious and tantalizing next question is whether these oceans can support extraterrestrial life. Liquid water is an important piece of what makes for a habitable world, but far from the only requirement for life. Life also needs energy and certain chemical compounds in addition to water to flourish. Because these oceans are hidden beneath miles of solid ice, sunlight and photosynthesis are out. But it’s possible other sources could provide the needed ingredients.
On Europa, for example, the liquid water ocean overlays a rocky interior. That rocky seafloor could provide energy and chemicals through underwater volcanoes that could make Europa’s ocean habitable. But it is also possible that Europa’s ocean is a sterile, inhospitable place – scientists need more data to answer these questions.
Upcoming missions from ESA and NASA
Europa Clipper and JUICE are set up to give scientists game-changing information about the potential habitability of Jupiter’s moons. While both missions will gather data on multiple moons, JUICE will spend time orbiting and focusing on Ganymede, and Europa Clipper will make dozens of close flybys of Europa.
Both of the spacecraft will carry a suite of scientific instruments built specifically to investigate the oceans. Onboard radar will allow Europa Clipper and JUICE to probe into the moons’ outer layers of solid ice. Radar could reveal any small pockets of liquid water in the ice, or, in the case of Europa, which has a thinner outer ice layer than Ganymede and Callisto, hopefully detect the larger ocean.
Magnetometers will also be on both missions. These tools will give scientists the opportunity to study the secondary magnetic fields produced by the interaction of conductive oceans with Jupiter’s field in great detail and will hopefully give researchers clues to salinity and volumes of the oceans.
Scientists will also observe small variations in the moons’ gravitational pulls by tracking subtle movements in both spacecrafts’ orbits, which could help determine if Europa’s seafloor has volcanoes that provide the needed energy and chemistry for the ocean to support life.
Finally, both craft will carry a host of cameras and light sensors that will provide unprecedented images of the geology and composition of the moons’ icy surfaces.
Maybe one day, a spacecraft will be able to drill through the miles of solid ice on Europa, Ganymede or Callisto and explore oceans directly. Until then, observations from spacecraft like Europa Clipper and JUICE are scientists’ best bet for learning about these ocean worlds.
When Galileo discovered these moons in 1609, they were the first objects known to directly orbit another planet. Their discovery was the final nail in the coffin of the theory that Earth – and humanity – resides at the center of the universe. Maybe these worlds have another humbling surprise in store.
This article, originally published April 10, 2023, has been updated with details about the Europa Clipper launch.
Mike Sori, Assistant Professor of Planetary Science, Purdue University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
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Last Updated on April 11, 2026 by Daily News Staff
April 10, 2026 — NASA’s Artemis II crew has safely returned to Earth, marking the successful completion of the first crewed mission to the Moon’s vicinity in more than 50 years.
Credit: NASA/Joel Kowsky
The Orion spacecraft splashed down in the Pacific Ocean off the coast of California at 5:07 p.m. PDT, carrying NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian astronaut Jeremy Hansen back home after a nearly 10-day journey through deep space.
🚀 A Mission for the Record Books
During the mission, the crew traveled a total of 694,481 miles, reaching a maximum distance of 252,756 miles from Earth—farther than any humans have ever gone, surpassing the Apollo 13 record set in 1970.
Launched on April 1 aboard NASA’s powerful Space Launch System (SLS) rocket, Artemis II tested critical systems needed for future missions, including life support, navigation, and deep space communication.
🌕 Science, Exploration, and Stunning Views
While orbiting the Moon, the astronauts captured more than 7,000 images, including views of the lunar far side, a rare solar eclipse, and detailed observations of craters, lava flows, and surface features.
The mission also included scientific experiments to better understand how the human body responds to deep space conditions, helping prepare for longer missions to the Moon and Mars.
🛰️ Safe Return and Recovery
Following splashdown, recovery teams quickly reached the spacecraft and transported the crew by helicopter to the USS John P. Murtha for initial medical evaluations. The astronauts are expected to return to NASA’s Johnson Space Center for further assessments.
🌍 What Comes Next
With Artemis II complete, NASA is now turning its focus to Artemis III, the next mission aimed at landing astronauts on the Moon and establishing a long-term human presence.
The success of Artemis II marks a major step forward in humanity’s return to deep space—and the beginning of a new era of exploration.
For more information on NASA’s Artemis program, visit the official NASA website.
🔗 Source & Further Reading
- NASA Blog: Artemis II Flight Day 10 – Re-entry Live Updates
- NASA Artemis II Mission Overview
- NASA Artemis Program – Return to the Moon
- Orion Spacecraft Details and Technology
- NASA Image and Video Library (Artemis II Photos & Media)
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