phytoplankton

Fertilizing The Ocean | Earth Wise

January 23, 2023 By EarthWise Leave a Comment

There are a variety of schemes for removing carbon dioxide from the atmosphere. Some require advanced and generally not-very-well developed technology. Others, such as planting vast numbers of trees, are nature-based but are daunting with respect to the scale to which they need to take place in order to be truly effective.

Researchers at the Pacific Northwest National Laboratory in Richland, Washington have been examining the scientific evidence for seeding the oceans with iron-rich engineered fertilizer in order to feed phytoplankton. Phytoplankton are microscopic plants that are a key part of the ocean ecosystem.

Phytoplankton take up carbon dioxide as they grow. In nature, nutrients from the land end up in the ocean through rivers and from blowing dust. These nutrients fertilize the plankton. The idea is to augment these existing processes to increase the growth of phytoplankton. As they eventually die, they sink deep into the ocean, taking the excess carbon with them.

The researchers argue that engineered nanoparticles could provide highly controlled nutrition that is specifically tuned for different ocean environments. Surface coatings could help the particles attach to plankton. Some could be engineered with light-absorbing properties, allowing plankton to consume and use more carbon dioxide.

Analysis of over 100 published studies showed that numerous non-toxic, abundant, and easy-to-create metal-oxygen materials could safely enhance plankton growth. According to the researchers, the proposed fertilization would simply speed up a natural process that already sequesters carbon in a form that could remove it from the atmosphere for thousands of years. They argue that given the current trends in the climate, time is of the essence for taking action.

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Fertilizing the Ocean to Store Carbon Dioxide

Photo, posted August 2, 2007, courtesy of Kevin McCarthy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Less Phytoplankton In The Gulf Of Maine | Earth Wise

July 20, 2022 By EarthWise Leave a Comment

Phytoplankton, also known as microalgae, are the base of the marine food web and also play a key role in removing carbon dioxide from the air. They are eaten by primary consumers like zooplankton, small fish, and crustaceans.

Phytoplankton, like land plants, absorb carbon dioxide from the atmosphere and use photosynthesis to grow. Then they become a food source for other organisms and ultimately for people who depend upon marine ecosystems. If phytoplankton productivity is disrupted, there can be adverse effects on regional fisheries and the communities that depend on them.

The Gulf of Maine is becoming warmer and saltier, because of ocean currents pushing warm water into the gulf from the Northwest Atlantic. These temperature and salinity changes have led to a significant decrease in the productivity of phytoplankton. According to a new paper from scientists at Bigelow Laboratory of Ocean Sciences in Maine, phytoplankton are about 65% less productive in the gulf than they were 20 years ago.

The study’s results come from the analysis of the Gulf of Maine North Atlantic Time Series, a 23-year sampling program of the temperature, salinity, chemical, biological, and optical measurements of the gulf. The scientists refer to what they describe as a giant windmill effect happening in the North Atlantic, which is changing the circulation of water coming into the Gulf of Maine. In the past, inflows from the North Atlantic brought water from the Labrador Current, which made the gulf cooler and fresher. The new circulation is making the water warmer and saltier.

These changes have significant implications for higher marine species, fisheries, the lobster industry, and other activities in the states that border the Gulf of Maine.

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NASA-funded Study: Gulf of Maine’s Phytoplankton Productivity Down 65%

Photo, posted November 15, 2015, courtesy of Paul VanDerWerf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Large Mammals And Climate Change | Earth Wise

April 14, 2022 By EarthWise Leave a Comment

The natural world has an important part to play in mitigating the effects of climate change. We mostly think about the role of plant life which absorbs carbon in trees, grasses, and other flora. However, a new study published by Oxford University looks at the role of large wild animals in restoring ecosystems and reducing the effects of climate change.

According to the study, there are three important ways in which large animals such as elephants, rhinos, giraffes, whales, bison, and moose can potentially mitigate the effects of climate change: carbon stocks, albedo, and fire regimes.

When large herbivores graze, they disperse seeds, clear vegetation, and fertilize soil. All of these things build more complex and resilient ecosystems which helps to maintain and increase carbon stocks in the soil and in plant tissues thereby helping to reduce CO2 in the atmosphere.

Grazing large animals trample vegetation which opens up areas of dense vegetation to create open mixes of grass and shrubs and can reveal snow-covered ground in cold regions. Such open habitats are lighter in color (higher in albedo) and reflect more solar radiation into the atmosphere, cooling the Earth’s surface rather than heating it up.

Large grazing animals can lessen wildfire risk by browsing on woody vegetation that would otherwise fuel the fires and also by creating paths that act as firebreaks.

In marine ecosystems, whales and other large animals fertilize phytoplankton, which capture some 37 billion tons of CO2 each year.

Overall, large animals are an important part of the natural world’s ability to reduce the effects of the changing climate by helping with localized adaptation to the changes taking place in ecosystems.

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Large mammals can help climate change mitigation and adaptation

Photo, posted August 20, 2017, courtesy of Jon Niola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Whales As Ecosystem Engineers | Earth Wise

December 14, 2021 By EarthWise Leave a Comment

Researchers from Stanford University have been studying the role of large whales on ocean ecosystems with some surprising results.

From 1910 to 1970, people killed about 1.5 million baleen whales in the waters surrounding Antarctica. The whales were hunted for their blubber, baleen, and meat. Baleen is the filtering fringe that certain whales use instead of teeth to capture food from the ocean. A primary food source for these whales is krill, small shrimp-like creatures. One would assume that the decimation of the baleen whale population in the Southern Ocean would have led to a surge in krill populations. But the new research has found that the opposite is the case.

The precipitous decline of large marine mammals has negatively impacted the health and productivity of ocean ecosystems.

New high-tech tagging devices that attach to whales for brief periods allow researchers to record their movements and activities. For the first time, it has been possible to accurately determine how much krill whales actually consume, and the answer is that they eat two to three times as much as previously thought. Interestingly, the same technology shows that fish-eating whales like humpbacks eat somewhat less than previously thought.

Baleen whales are essentially mobile krill processing plants. They eat the krill, digest it, and produce iron-laden excretions that are needed by phytoplankton, which comprise the bottom of the food chain that nourish krill and other small creatures. With fewer whales, there is less nourishment for the krill. In fact, based on the new data, estimates are that the historic abundance of krill in the Southern Ocean had to be about five times what it is today.

Whales are important ecosystem engineers.

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Stanford researchers find whales are more important ecosystems engineers than previously thought

Photo, posted November 18, 2010, courtesy of Dr. Brandon Southall, NMFS/OPR via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildfires And Algal Blooms

October 12, 2021 By EarthWise Leave a Comment

Australia is no stranger to wildfires. But the 2019-2020 season proved to be particularly severe: wildfires destroyed 3,100 homes, displaced 65,000 people, and burned more than 72,000 square miles – roughly the same size as Washington State. The season is colloquially referred to as the Black Summer.

According to a new study recently published in the journal Nature, clouds of smoke and ash from these wildfires triggered widespread algal blooms thousands of miles downwind to the east in the Southern Ocean.

The study, which was led by researchers from Duke University, shows that aerosol particles in the smoke and ash fertilized the water as they fell into it. This provided the nutrients that fueled unprecedented blooms in that region, conclusively linking for the first time a large-scale response in marine life to fertilization by pyrogenic iron aerosols from a wildfire.

This finding raises questions about the role wildfires may play in the growth of phytoplankton, the microscopic marine algae that – through photosynthesis – absorbs large amounts of climate-warming carbon dioxide from Earth’s atmosphere.

According to the research team, the Australian algal blooms were so extensive that the subsequent increase in photosynthesis may have temporarily offset a substantial portion of the wildfires’ CO2 emissions. It remains to be seen how much of the absorbed CO2 remains safely stored in the ocean and how much it has been released back into the atmosphere.

The researchers plan to investigate the fate of the phytoplankton further. They also plan more research to better predict where and when aerosol deposition will boost phytoplankton growth in the future.

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Australian wildfires triggered massive algal blooms in Southern Ocean

Photo, posted January 12, 2020, courtesy of BLM-Idaho via Flickr.

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A Powerful Case For Protecting Whales

October 24, 2019 By EarthWise Leave a Comment

Efforts to mitigate climate change typically face two major challenges. One is to find effective ways to reduce the amount of atmospheric carbon dioxide. The other is how to raise enough money to implement climate mitigation strategies.

Many proposed solutions to climate change, like carbon capture and storage, are complex, expensive, and in some cases, untested. What if there was a low-tech solution that was effective and economical?

Well, it turns out there is one, and it comes from a surprisingly simple, “no-tech” strategy to capture CO2: increase global whale populations.

According to a recent analysis by economists with the International Monetary Fund, whales help fight climate change by sequestering CO2 in the ocean.

Whales sequester carbon in a few ways. They hoard it in their fat and protein-rich bodies, stockpiling tons of carbon apiece. When whales die, they turn into literal carbon sinks on the ocean floor. While alive, whales dive to feed on tiny marine organisms like krill and plankton before surfacing to breathe and excrete. Those latter activities release an enormous plume of nutrients, including nitrogen, iron, and phosphorous, into the water. These so-called “poo-namis” stimulate the growth of phytoplankton, microscopic marine algae that pull CO2 out of the air and return oxygen to the air via photosynthesis. Phytoplankton are responsible for every other breath we take, contributing at least 50% of all oxygen to the atmosphere and capturing approximately 40% of all CO2 produced.

With other economic benefits like ecotourism factored in, economists estimate that each whale is worth $2 million over its lifetime, making the entire global population possibly a one trillion dollar asset to humanity.

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How much is a whale worth?

Photo, posted June 12, 2013, courtesy of Gregory Smith via Flickr.

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Alien Waters Invade The Arctic

June 18, 2018 By EarthWise Leave a Comment

The Arctic is heating up faster than any other region of the planet. As a result, once-distinct boundaries between the frigid polar ocean and the warmer, neighboring Atlantic and Pacific Oceans are blurring, opening the way for the southern waters to enter the polar regions. The volume of Pacific Ocean water flowing into the Arctic Ocean through the Bering Strait has increased by 70% over the past decade. The Arctic Ocean’s cold layering system that blocks Atlantic inflows is breaking down.