Life Under the Sea: WARC Ocean Science

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Nearly two-thirds of our planet is covered by water with more than 120 million Americans living near an ocean or Great Lake. Celebrate Ocean Month and learn more about USGS ocean science research!

This June marks National Ocean Month. As part of the USGS Ecosystems Mission Area, WARC science helps inform the management of marine resources and the ecosystems that sustain these resources.

 

Why is the ocean salty?

(Creative Commons, Pixabay)

From the microscopic plants known as phytoplankton that form the basis of the aquatic food web

to the largest animal to ever live on Earth, the blue whale;

From color changing cephalopods like cuttlefishes and octopuses that propel themselves through the water column

to translucent jellyfish that float along with currents;

From the “Aww!”-inducing antics of paw-holding sleeping sea otters

to the alien-like deep-sea animals that inspire horror movies;

Our oceans are home to a wealth of biodiversity and every organism plays a critical role in the structure and function of this expansive marine environment. Maintaining this biodiversity is important because a healthy ocean provides us with oxygen, helps regulate climate and weather, acts as a source of protein for many people around the world, and provides jobs and opportunities for eco-tourism and recreation. USGS WARC science informs the management and conservation of marine biodiversity and habitats, from the coastlines down to the deepest trench.

 

Fig. 3. Loggerhead sea turtle, Cape San Bas, FL

The Gulf of Mexico Marine Assessment Program for Protected Species (GoMMAPPS) represents a multi-agency partnership dedicated to collecting broad-scale survey data for seabirds, marine mammals, and sea turtles. These surveys help determine species distribution and abundance in the Gulf of Mexico. Using aerial and vessel-based surveys, satellite tracking, and genetic analyses, USGS scientists are leading the charge on understanding sea turtle distribution and abundance, movement patterns, behavior, and habitat use.

Tracking Sea Turtles

One of the most charismatic of all the marine megafauna, sea turtles are among the oldest living animals on our planet. There are seven sea turtle species worldwide, six of which can be found in the waters off the United States. With study sites in the Gulf of Mexico, the Florida Keys, and the Caribbean (namely, the U.S. Virgin Islands, or USVI), much of WARC’s sea turtle research in the southeast focuses on four species, all of which are listed as endangered or threatened under the Endangered Species Act: greens, hawksbills, Kemp's ridleys, and loggerheads.

Besides the occasional breath at the sea surface or when females come ashore to lay their eggs, sea turtles spend most of their lives underwater. With the help of satellite and acoustic telemetry, USGS WARC scientists have been able to track the movement of sea turtles to help identify migration routes, habitat use, and foraging areas. This information helps assess their use of marine protected areas and offers managers a view into where and when human and turtle activities overlap.

Hatchling sea turtle heads to sea

Sea turtle nesting season runs from April to November. After a female sea turtle has laid her eggs, the USGS scientists insert a tag, much like a microchip used in pets, into her left shoulder for future identification. They also collect biological samples and measurements like shell length and width, and a few turtles receive transmitters that track their movements via satellite. This information helps inform management of the sea turtle species and the habitats they rely on, as well as local communities’ decisions about beach driving, night lighting, construction permits, and road work – activities that can disrupt turtle nesting behaviors.

Coral Reefs

When you think of “coral reefs,” you might envision a tropical seascape complete with warm temperatures and crystalline blue water as multicolored fishes dart about you. Often referred to as “the rainforests of the sea,” these shallow-water coral reefs are filled to the brim with diversity. Even though they cover less than 1% of the seafloor, coral reefs house more than 25% of marine life, including eye-catching fishes; sea stars; stingrays; crustaceans, like shrimp, lobsters, and crabs; and even the occasional shark. These animals depend on healthy coral reefs for feeding, breeding, habitat, and as a nursery for their young.

Coral reefs are also important to us. They provide coastal protection from storms, flooding, and erosion; reef inhabitants like sponges are a source of new medicines that could be developed to help treat various diseases; and local economies benefit from ecotourism activities like snorkeling and diving that revolve around healthy coral reef ecosystems.

Coral reefs in the Caribbean have been dealt their fair share of troubles. In 2005, increased sea surface temperatures led to widespread coral bleaching. Just a few months later, coral disease hit the already weakened corals causing an average 60% loss in coral cover. Now, USGS scientists are assessing how coral communities on St. John, USVI, were affected by the 2017 hurricane season. Hurricanes Irma and Maria caused widespread destruction over much of the island, including mangrove forests and corals in Hurricane Hole, the most visited part of the Virgin Islands Coral Reef National Monument. In 2014, Rogers and partners documented over 30 species of corals growing on or near mangroves in Hurricane Hole, indicating the mangroves provide refuge from thermal and irradiance stress and ocean acidification. Now, WARC scientists are documenting the damage within Hurricane Hole to evaluate hurricane effects on corals and mangroves and their recovery potential, and to learn more about how these ecosystems respond to natural disasters and changing climate.

Coral reefs are also exposed to environmental contaminants, some of which are known endocrine disruptors, immunosuppressors, and/or toxins that can stress corals and other reef organisms. On St. John, USVI, WARC research is focused on assessing the presence of contaminants, organotin compounds like those commonly used in anti-fouling paints on boats, and sunscreen compounds (like benzophenone-3). The Virgin Islands National Park includes sensitive marine habitats that are home to a number of vulnerable organisms including several federally listed coral species. This research will offer a better understanding of the risk from sunscreen chemicals for coral reefs on St. John.

Hurricane Hole, St. John, USVI before and after Hurricanes Irma and Maria in 2017

Hurricane Hole, St. John, USVI before and after Hurricanes Irma and Maria in 2017.  (Credit: Caroline Rogers, USGS.)

 

squat lobster

A single Eumunida picta squat lobster on a thicket of live deep-sea coral known as Lophelia pertusa.​​​​​​​ (Credit: Lophelia II 2012 Expedition, NOAA-OER/BOEM. Image courtesy of Lophelia II 2012 Expedition, NOAA-OER/BOEM)

Deepwater Ecosystems

Most life in the ocean exists in surface waters above 200 meters depth where they have access to sunlight. However, even below 200 meters, where little to no sunlight reaches, temperatures drop, and pressure increases, abundant life exists. A diversity of organisms, including fishes, crustaceans, anemones, sea stars, microbes, and even corals make their home in the deep sea.

From the Atlantic to the Pacific and the Gulf of Mexico in between, scientists from WARC and four other USGS science centers have implemented a multi-faceted offshore research program that weaves together expertise in a variety of disciplines to investigate deepwater ecosystems like trenches, seamounts, canyons, and coral reefs. This interdisciplinary approach relies on a network of partners from around the Nation and the world to examine microbiology, population genetics, paleoecology, food webs, taxonomy, community ecology, physical oceanography, seafloor characteristics, and submarine hazards in the little explored, yet vital, deep-sea ecosystems.

 

 

 

 

It truly takes an immense effort by scientists with varied expertise to explore the biodiversity that lives within the depths of our oceans. However, with more than eighty percent of our ocean still unobserved and unexplored, many of the ocean’s mysteries have yet to be revealed.

Keep on learning about WARC ocean science by following us on Twitter and check out the newest issue of Sound Waves newsletter to learn what other USGS centers are doing to better understand the ocean!