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A sustainable future: Transformative marine stewardship

By Mary Hare

With areas of distinction in marine sciencematerials sciencedata science, biomedical science – and other research areas, OSU faculty and students are fighting climate change and moving the world forward to a greener future – whether that is through harnessing new materials, interpreting complex data or reimagining how organisms can adapt to changes. We share just a few examples in this three-part series.

With expertise spanning marine ecology, biofuel development, new modes of energy capture, evolutionary genetics and the microbiomes of coral reefs, student and faculty researchers at Oregon State University are committed to using science to help create a livable planet for the future. 

Oregon State has firmly established itself as a world leader in marine science. Our faculty are frequently called upon for their expertise in coral reef bleaching, ocean acidification and coastal ecosystem preservation. They exemplify the College’s dedication to leadership on the world stage - with Distinguished Professor of Integrative Biology Jane Lubchenco currently serving as  Deputy Director for Climate and the Environment for the Biden Administration, and several faculty holding leadership roles in other federal institutions. 

The fight to save coral reefs in peril

Although coral reefs make up a small percentage of ocean floor coverage, scientists believe they contain even more biodiversity than a tropical rainforest – or anywhere else in the world. Home to nearly one-quarter of all known marine species, coral reefs help regulate the sea’s carbon dioxide levels and are a crucial hunting ground that scientists use in the search for new medicines. 

Corals are made up of delicate living organisms, which live symbiotically with tiny colorful algae known as zooxanthellae. The zooxanthellae live inside the corals, and provide them with energy as well as their color. Corals are particularly sensitive to changes in temperature. Climate change-induced spikes in global temperatures cause corals to lose their zooxanthellae, which leads to starvation and often death. At extreme temperatures, distressed corals may die immediately, leaving a white skeleton barren of the nutrients the reef ecosystems depend on, which is known as mass bleaching.

The first mass bleaching event ever recorded occurred in 1998, and since then it has become an increasingly significant problem. A heatwave from 2014-17 caused a third mass bleaching event that affected more than 75% of tropical corals throughout the world. Since their first appearance 425 million years ago, corals have branched into more than 1,500 species, including the one at the center of this research: the critically endangered Acropora cervicornis, commonly known as the Caribbean staghorn coral.

In 2019, scientists in the lab of microbiology Associate Professor Rebecca Vega Thurber identified a new genus of parasitic bacteria that flourishes when reefs become polluted with nutrients, siphoning energy from the corals and making them more susceptible to disease. “The bacterial genus we’ve identified is found around the world and in multiple types of corals, but is most notably found in high abundance in the microbiomes of Caribbean staghorn coral,” said study co-author Grace Klinges, also a Ph.D. candidate in the Vega Thurber lab.

Meanwhile, biologist Virginia Weis has long been regarded as a world expert in the cell biology of coral-algae symbiosis. For more than two decades, her research has focused on the symbiotic association between corals and the algae they harbor within their cells, and the role of this mutualistic relationship in the foundation and sustenance of healthy coral reef ecosystems.

In her laboratory, Weis and her graduate students closely examine the molecular partnership between corals and algae, their communication and signaling patterns that regulate the symbiosis, and how dysbiosis or a breakdown in partnership results under conditions of stress induced by heat and environmental pollution. They are also investigating gene editing techniques that could alter the molecular cellular make-up of the symbionts of host animals. The long-term goal would be to provide the tools for engineering corals that are more resilient to bleaching. 

Giovannoni lab performs research off of a boat
Oregon State University microbiologists participate in BIOS-SCOPE, a five-year, multi-institutional research program for the study of microbial oceanography in the North Atlantic Ocean. BIOS-SCOPE leverages ocean measurements and ongoing research at the Bermuda Atlantic Time-series Study site, bringing new collaborations and technologies to study the ocean’s smallest life forms.

Standing up for Oregon’s oceans

Oxygen starvation in sea life close to home

The Northwest for two decades has had a “hypoxia season” that begins in mid-summer, said OSU marine ecologist Francis Chan, and climate change is making those low-oxygen seasons worse. When oxygen levels drop significantly, many marine organisms that are place-bound or cannot relocate quickly enough, such as Dungeness crabs, die of oxygen starvation. Hypoxia occurs because summertime north winds bring nutrient-rich but oxygen-poor ocean waters to shores – factors that are exacerbated by climate change.

Oregon’s coastal waters originate in the cold waters of the North Pacific off Japan and can take up to 60 years to reach us. Meanwhile, 25-30 percent of the pollution emitted from fossil fuel combustion is being absorbed in the ocean’s surface. Over time, this deadly combination has caused as much as a 30 percent increase in ocean acidity in the waters off the Oregon coast.

Last year, Oregon State was selected by the National Oceanic and Atmospheric Administration (NOAA) to lead the Cooperative Institute for Marine Ecosystem and Resources Studies, eligible for up to $37 million in funding over the next five years. With Chan as director, the institute will support collaborative marine research around the world, with emphasis on the Northeastern Pacific Ocean.

The quest to save a Pacific Northwest icon

The iconic sunflower sea star has been listed as critically endangered by the International Union for Conservation of Nature following a groundbreaking population study led by Oregon State University and The Nature Conservancy. Biology postdoctoral scholar Sarah Gravem was lead author on the study, along with University Distinguished Professor of Integrative Biology Bruce Menge. Populations of the sunflower sea star suffered dramatic crashes because of a marine wildlife epidemic event, referred to as sea star wasting syndrome, that began in 2013. “This listing is one step above extinction — and I don’t think they’re coming back without help like captive rearing and reintroduction and reducing direct harvest and accidental harvest,” said Gravem. More than 60 institutions joined the population study on the sunflower sea star, known scientifically as Pycnopodia helianthoides, which plays an important role in maintaining kelp forests, and thus sustaining marine life, along the West Coast from Alaska to Baja, California.

Working in Menge and Assistant Biology Professor Felipe Barreto’s Labs, biology student Kristofer Bauer assisted in the genetic analysis of sea stars to study their genetic resistance to sea star wasting disease. He witnessed first-hand the value of research. “I saw the impact that our research was having on understanding the effects of climate change on marine ecosystems and fisheries in Oregon. I saw that as something bigger than myself that I wanted to be a part of,” said Bauer.

Leadership on the world stage

Leaders of 14 major maritime nations have announced their commitment to achieve 100% sustainable ocean management of their national waters by 2025, acting on recommendations of global experts co-chaired by marine ecologistJane Lubchenco. The group was commissioned by the High Level Panel for a Sustainable Ocean Economy (Ocean Panel), a group of nations representing nearly 40% of the world’s coastlines.

As Expert Group co-chair, Lubchenco helped coordinate experts from 48 countries, including OSU scientists Kirsten Grorud-Colvert and Jenna Sullivan, in the production of 19 peer-reviewed papers, plus an Ocean Solutions Report to the Ocean Panel. The results, the panel says, would include producing up to six times more food from the ocean, generating up to 40 times more renewable energy, lifting millions of people from poverty and contributing 20% of the global greenhouse gas emission reductions needed by 2050 to stay within the 1.5° Celsius limit of the 2016 Paris Agreement. “It is exciting and gratifying to see presidents and prime ministers ask for, listen to and follow scientific guidance,” said Lubchenco.

closeup view of phytoplankton
Like marine plants, phytoplankton have chlorophyll to capture sunlight use photosynthesis to turn it into chemical energy. The foundation of the oceanic food web, they store an immense amount of carbon - critical to preventing a future climate emergency. 

The ocean as a carbon sink: Unexplored potential, and unforeseen risks

North Atlantic phytoplankton sampling

The ocean has long been regarded as one of the earth’s most important natural carbon sinks, storing around 80% of all carbon on the planet. Phytoplankton, aquatic microorganisms which serve as the foundation of the food web, consume carbon at a level equivalent to terrestrial forests. When they are eaten or decompose, the carbon dissolves into the ocean. Phytoplankton are responsible for almost all carbon uptake in the ocean, but just how this process will be affected by climate change remains uncertain. OSU microbiologists have made significant contributions to this field, questioning preconceived notions about which the world cannot afford complacency.

When considering the ocean as a carbon sink, the spring phytoplankton bloom in the North Atlantic is a clear winner. According to study author Steve Giovannoni, it is probably the largest biological carbon sequestration mechanism on the planet each year. In this yearly event, huge numbers of phytoplankton accumulate over thousands of square miles.

In the first-ever winter study of phytoplankton in the North Atlantic, microbiologist Steve Giovannoni and post-doc Luis Bolaños made a disturbing find. Diatoms, thought to dominate phytoplankton blooms in the North Atlantic, often were not a big part of the samples’ genetic profiles, and when they were a big part, the cells were small – either of the nano-phytoplankton variety or at the smaller end of the micro-phytoplankton scale.

Algorithms that predict carbon export from satellite-sensed chlorophyll tend to assign high export rates to phytoplankton blooms on the belief, based on observations from the eastern North Atlantic, that large diatoms dominate at their climax. The findings of this study, Giovannoni said, suggest that extrapolating those observations to the western North Atlantic may not be a valid practice.

Heterotrophic carbon cycling

In October, associate professor Ryan Mueller led a study that shed new light on the mechanisms of carbon cycling in the ocean, using a novel approach to track which microbes are consuming different types of organic carbon produced by common phytoplankton species.

As the ocean pulls in atmospheric carbon dioxide, phytoplankton use the CO2 and sunlight for photosynthesis: They convert them into sugars and other compounds the cells can use for energy, producing oxygen in the process. This so-called fixed carbon makes up the diet of heterotrophic microbes and higher organisms of the marine food web such as fish and mammals, which ultimately convert the carbon back to atmospheric CO2 through respiration or contribute to the carbon stock at the bottom of the ocean when they die and sink.

The collective respiratory activity of the heterotrophic microbial consumers is the main way that fixed dissolved organic carbon from phytoplankton is returned to the atmosphere as CO2. In his study, Mueller used stable isotope labeling to track carbon as it made its way into the organic matter produced by the phytoplankton and, ultimately, the heterotrophic microbes that consume it. The research is an important step toward forecasting how much carbon will leave the ocean for the atmosphere as greenhouse gas carbon dioxide and how much will end up entombed in marine sediments.

Photo of Glen Canyon Dam
Downstream of Glen Canyon Dam, researchers are implementing experimental flow releases as a way to minimize ecological damage to aquatic insects.  Aquatic insect and sensitive taxa are negatively associated with hydropeaking intensity, which limits the composition and potentially the quality of the invertebrate food base.

New management solutions for river ecosystems

Hydropower dams are a renewable alternative to fossil fuels, but they are not without their downsides. Large hydropower dams alter the flow of the river by creating physical barriers that alter the river’s flow regime, as well as dissolved oxygen levels, nutrients and temperature.

Biologist David Lytle teamed up with scientists from the United States Geological Survey in a project to examine how the Colorado river’s seven large dams affect aquatic invertebrate biodiversity. While on a seasonal or annual scale, hydropower dams are known to reduce the average variation in the flow level, surges in power usage throughout the day cause a phenomenon known as hydropeaking.

As the earth continues to warm, rivers have experienced steep declines in water availability; last summer, only 30% of the average amount of water entered the Colorado, with other rivers experiencing similar trends. With water availability already limited, daily water-level fluctuations may prove intolerable for many species. While declining snowpacks and drier summers may be unavoidable, Lytle’s research may help provide strategies to manage water release from dams to minimize the ecological impacts. “Invertebrates are food for fish, birds and bats, and we want to enhance that food base by testing out different flow regimes that mesh with management ideas.”

In part three of this series, learn how OSU researchers are harnessing data to uncover new perspectives on resource management, using simulations to predict possible outcomes and using their unique skills to advance climate research across many disciplines.