Science Snippets: Priorities, Redux

Draft script:

I recently released a video focused on priorities. Priorities apply to individuals as well as society, although I recognize that individuals have little control over society. Societal actions are beyond the ability of the masses to influence. Exceptions include billionaires and, to a lesser extent, politicians. This video focuses, again, on priorities. I will start with two topics I have discussed previously in this space.

I have written and spoken a few times about ocean acidification. An overview can be found at a video extracted from my long essay, Climate Change Summary. In short, ocean acidification is proceeding at a rate unparalleled during the last 300 million years, according to a peer-reviewed paper in the renowned journal, Science. This video indicates that the situation has worsened during the nearly five years that have passed since I created that short video.

An article at Phys.Org published 12 March 2025 is titled Eukaryotic phytoplankton decline due to ocean acidification could significantly impact global carbon cycle. Here’s the expansive lede: “Princeton University and Xiamen University researchers report that in tropical and subtropical oligotrophic waters, ocean acidification reduces primary production, the process of photosynthesis in phytoplankton, where they take in carbon dioxide …, sunlight, and nutrients to produce organic matter (food and energy).”

The next two paragraphs indicate the importance of this research-based information: “A six-year investigation found that eukaryotic phytoplankton decline under high CO₂ conditions, while cyanobacteria remain unaffected. Nutrient availability, particularly nitrogen, influenced this response.

Results indicate that ocean acidification could reduce primary production in oligotrophic tropical and subtropical oceans by approximately 10%, with global implications. When extrapolated to all affected low-chlorophyll ocean regions, this translates to an estimated 5 billion metric tons loss in global oceanic primary production, which is about 10% of the total carbon fixed by the ocean each year.”

“Global implications,” indeed. Oceans sequester a tremendous amount of carbon, acting as a storage bank for carbon dioxide and heat. Global oceans absorb about 30% of the carbon released into the atmosphere. They hold 50 times more carbon than the atmosphere. In the process of sequestering all this carbon, the oceans become more acidified. Ocean acidification is one of the consequences of carbon sequestration. When carbon is sequestered by the ocean, the increased concentration of hydrogen ions leads directly to acidification.

The final paragraph of the article at Phys.Org indicates the potential disaster associated with ocean acidification: “These findings suggest that ongoing ocean acidification may significantly alter carbon cycling in nutrient-depleted marine ecosystems, potentially impacting global fisheries and food webs, with long-term implications for accelerating climate change through reduced ocean sequestration capacity.” This “reduced ocean sequestration capacity” is a cause for serious concern.

I now turn to the peer-reviewed paper mentioned in the Phys.Org article. Written by 10 scholars for the renowned Proceedings of the National Academy of Sciences, the paper is titled Eukaryotic phytoplankton drive a decrease in primary production in response to elevated CO₂ in the tropical and subtropical oceans. The peer-reviewed paper begins with a Significance section: “Marine phytoplankton, which contribute ~45% of global net primary production, are projected to be affected by ongoing ocean acidification ... However, the response of phytoplankton to acidification is not well constrained in ultraoligotrophic tropical and subtropical oceans where small (<20 millionths of a meter …) phytoplankton dominate. By conducting onboard microcosm experiments, we found community-level primary production decreased consistently following CO₂ enrichment in the North Pacific Subtropical Gyre and northern South China Sea, while no significant changes were observed at the northernmost boundary of the subtropical gyre. Eukaryotic phytoplankton but not cyanobacteria were key drivers of these responses which occur primarily under nitrogen limitation. These findings enhance our understanding of OA impacts on phytoplankton and marine productivity in a changing climate.”

The Abstract of the peer-reviewed paper indicates that “extrapolating these results to global tropical and subtropical oceans predicts a potential decrease of about 5 Pg C/year in primary production.” Pg is short for petagram, a unit of mass equal to 10 to the 15th power. In other words, the Abstract of the peer-reviewed paper indicates that we can expect a huge reduction in primary production as a result of ocean acidification. Considering there are already too many people on this overcrowded Earth, a significant reduction in food at the bottom of the food web indicates some of those people will not persist in the face of reduced primary productivity.

Perhaps we can switch to land-based food production, rather than relying on the seas. Unfortunately, recent research indicates otherwise. Specifically, an article published by Phys.Org on 4 March 2025 points to a paper in the peer-reviewed, open-access Nature Communications. The Phys.Org article is titled Agriculture is main cause of seasonal carbon ups and downs, study finds. It opens with this paragraph: “The overall amount of carbon dioxide in the atmosphere has been steadily increasing, a clear trend linked to human activities and climate change. Less concerning but more mysterious, the difference between the highest and lowest amounts of carbon dioxide in the atmosphere each year has also been increasing.” The Phys.Org article indicates that agriculture is the primary cause of these seasonal swings in the atmospheric carbon cycle.

The peer-reviewed, open-access paper at Nature Communications is titled Agricultural fertilization significantly enhances amplitude of land-atmosphere CO₂ exchange. Published on 18 February 2025, it was written by 13 scholars. The Abstract indicates that multiple drivers contribute to the increased amplitude of CO₂. It concludes with a recommendation: “Our results emphasize the fundamental role of agricultural management in Northern Hemisphere carbon cycle feedbacks and illustrate that agricultural … [nitrogen] fertilization should be considered in future carbon cycle simulations.”

There is much to be done as Earth continues to lose habitat for human animals. Priorities vary among individuals, and few of us have any control other individuals or over outcomes. Our actions matter, albeit primarily only to us. Acting otherwise is a prescription for disappointment. However, on the rare occasion we can positively influence the life of another, our character indicates we must.