Algae's hidden role in ocean air pollution

1 min read

In the vast expanse of marine ecosystems, a new source of nitrous acid (HONO) has been identified: abiotic photodecomposition of marine algae. This process, which involves the breakdown of algae by sunlight, was found to produce HONO under irradiation. Chamber experiments confirmed that common marine algae emit HONO when exposed to light, with fluxes increasing as the intensity and surface area of the algal material increase.

This discovery is significant because it highlights a previously unrecognized mechanism for HONO production in the ocean. Unlike microbial soil processes, which are well-documented, this abiotic process is distinct and occurs under specific conditions. The measured fluxes of HONO from algae under irradiation were found to be comparable to those from soil HONO emissions.

The implications of this finding are far-reaching, as it has been incorporated into atmospheric models to elevate HONO concentrations. This, in turn, enhances the production of hydroxyl radicals (OH) and ozone, with significant consequences for the oxidation of climate-relevant gases.

As we continue to grapple with the complex interactions between human activities and the natural world, this discovery serves as a poignant reminder of the intricate web of relationships within our planet's ecosystems. The emergence of HONO from marine algae underlines the dynamic nature of the ocean's chemistry, where even seemingly benign processes can have profound effects on the broader atmosphere.

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In the vast ocean, a tiny thread of light unravels a hidden story. Marine algae, those green and vibrant giants of the sea, are not just simple plants; they're also tiny factories that churn out nitrous acid, a potent precursor to hydroxyl radicals. This discovery was born from the observation that during Ulva prolifera's infamous green tides, daytime HONO levels mirrored the tidal cycles - peaking at low tide, when the sun's rays were strongest.

It turns out that these algae are not just passive victims of the sun; they're actually tiny producers of HONO. Chamber experiments confirmed this: under irradiation, common algae like Ulva prolifera and Sargassum emit HONO, with its release increasing with light intensity and surface area. This process is distinct from microbial soil production and is a previously unrecognized source of HONO.

The implications are significant: by incorporating this new source into atmospheric models, scientists found that it substantially elevated HONO concentrations, boosting the formation of ozone and oxidizing climate-relevant gases. As global algal blooms intensify due to eutrophication and climate warming, this process is expected to become increasingly important. The story of these tiny algae serves as a reminder of the intricate web of life that underpins our planet's ecosystems - and how even the smallest details can have a profound impact on our world.

1 min read

In the ocean, a tiny plant called Ulva prolifera grows and thrives. It makes its own food from sunlight, just like plants on land. But as it grows, it releases something into the air that can help form other important chemicals in our atmosphere. Scientists have discovered that when this algae is exposed to sunlight, it turns into a gas called nitrous acid - or HONO for short.

What's amazing is that this process happens all day long during high tides, and it produces more HONO than we thought was possible. This gas can then react with other chemicals in the air to form even more important substances like ozone and hydroxyl radicals. This discovery helps us understand how our oceans are connected to the air around us, and how changes in the ocean might affect our atmosphere - a connection that's becoming increasingly clear as algae blooms grow stronger due to climate change.