Nav: Home

Flathead Bio Station researcher helps uncover ocean iron level mystery

August 29, 2019

POLSON, MONTANA - The middle of the Earth's oceans are filled with vast systems of rotating currents known as subtropical gyres. These regions occupy 40% of the Earth's surface and have long been considered remarkably stable biological deserts, with little variation in chemical makeup or the nutrients needed to sustain life.

However, there exists a strange anomaly in the North Pacific Subtropical Gyre ecosystem that has puzzled scientists for years. In this region that occupies the Pacific Ocean between China and the United States, the chemistry changes periodically. There's a particularly notable fluctuation in the levels of phosphorus and iron, which affects the overall nutrient composition and ultimately impacts biological productivity.

In a new study published in the Proceedings of the National Academy of Sciences, a group of researchers uncovered the reason behind these variations in the North Pacific Subtropical Gyre ecosystem. The group includes Matthew Church, a microbial ecologist with the University of Montana's Flathead Lake Biological Station, as well as Oregon State University's Ricardo Letelier and the University of Hawaii's David Karl, among others.

"Variations in ocean climate appear to regulate iron supply, altering the types of plankton growing in these waters, which ultimately controls ocean nutrient concentrations," Church said. "My laboratory has worked on questions related to the role of plankton in controlling ocean nutrient availability for many years, and this study places much of that work in context. As a result of sustained, long-term observations, our work confirms how tightly coupled plankton biology is to the supply of nutrients, specifically iron, delivered from the atmosphere."

Using three decades of observational data from Station ALOHA, a six-mile area in the Pacific Ocean north of Hawaii dedicated to oceanographic research, the team discovered that the periodic shift in iron levels result from iron input from Asian dust, accounting for the chemical variances and providing varying amounts of nutrients to sustain life.

The key to the variance is the Pacific Decadal Oscillation, an ocean-atmosphere relationship that varies between weak and strong phases of atmospheric pressure in the northeast Pacific Ocean.

In years when the low pressure weakens in the northeast Pacific, winds from Asia become stronger and move in a more southern direction. This brings more dust from the Asian continent, "fertilizing" the ocean surrounding Station ALOHA. When the pressure strengthens, the opposite occurs.

The supply of nutrients is a fundamental regulator of ocean productivity, and phosphorous and iron are key components for life. Typically, the ocean's upper water column is fertilized by nutrient-rich water mixing up from the deep. This is a difficult process in the North Pacific Subtropical Gyre ecosystem because the waters are very stratified and little mixing actually takes place.

When strong Asian winds bring in significant amounts of iron, organisms are allowed to grow and use phosphorus in the upper layers of the ocean. When Asian winds weaken and iron input is reduced, organisms are forced to return to a deep-water-mixing nutrient delivery system. This creates the periodic ebb and flow of iron and phosphorus levels in the North Pacific Gyre.

Church said the findings from this study emphasize the critical need to include both atmospheric and ocean circulation variability when forecasting how climate change might impact ocean ecosystems.

"It reaffirms the need to think about how tightly connected plankton biology is to changes in climate and ultimately also to changes in land use, which can directly impact dust supply to the sea," he said.

As Earth's temperature continues to warm, researchers expect to see long-term changes in wind patterns across the North Pacific. The evolution of land use and pollution driven by human activity in Asia also will affect the sources and magnitude of iron and other nutrients carried by wind across the ocean.

Further research is needed to better understand how these changes ultimately will impact ecosystems in this ocean region, as well as others around the world.
For more information about the study and Church's research, visit or email

The University of Montana

Related Climate Change Articles:

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.
Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.
Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.
Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.
Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.
A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.
Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
More Climate Change News and Climate Change Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.