The Effect of High Temperatures on Carbon Sequestration in Natural Wetlands.

[NNadir]

Here's a paper raising a disturbing topic about which I knew nothing at all, the relationship between tyrosine and carbon sequestration:

Biochemical Investigations of Five Recombinantly Expressed Tyrosinases Reveal Two Novel Mechanisms Impacting Carbon Storage in Wetland Ecosystems Felix Panis and Annette Rompel Environmental Science & Technology 2023 57 (37), 13863-13873.

The paper, which caught my eye because for a period of my career, when I was a kid, I was an amino acid chemist, is somewhat technical, is labeled as open to the public. Even if it is open to the public, an excerpt nonetheless:

Wetlands are ecosystems characterized by permanently or seasonally water-logged soils in combination with plant growth. (1,2) For most types of wetlands (peatlands, mangrove forests, bogs, and marshes), high levels of phenolic compounds have been reported. (3,4) Wetlands represent unbalanced ecosystems in which the rate of carbon sequestration from the atmosphere (via the Calvin cycle of plant photosynthesis) exceeds the rate of carbon release, predominantly as CO2 and CH4. (5,6) Thus, they have accumulated vast amounts of carbon over the last millennia. While wetlands cover only 5–8% of the terrestrial land surface, they are estimated to store 20–30% (500–550 × 10¹⁵ g) of the global soil carbon pool, which is equivalent to 66–72% of the entire atmospheric carbon pool of 760 × 10¹⁵ g. (2,7?9) Within recent years, the so-called “latch mechanism” has been established to explain how wetlands act as long-term carbon sinks (Figure 1A). According to the “latch mechanism,” the imbalance between carbon storage and release results from the inhibition of organic matter degrading enzymes (e.g., ?-glucosidases, peroxidases, xylosidases, and chitinases) (10?12) by phenolic compounds. Phenolic compounds act as unspecific enzyme inhibitors and are naturally abundant within wetland ecosystems (4,13) due to plant secondary metabolism. Enzymes capable of oxidatively removing phenolic compounds in the presence of molecular oxygen (or H2O2 for peroxidases) are often grouped under the umbrella term “phenol oxidases”, and include, among others, tyrosinases, laccases, and peroxidases. (4) In wetlands, the activity of phenol oxidases (and thus the removal of phenolic compounds) is restricted by oxygen scarcity, resulting from water-logging. (13) Climate change, which will lead to increased temperatures and reduced rainfall, threatens water tables in wetlands and will, therefore, promote the aeration of previously anoxic wetland soils. This, in turn, will lead to increased levels of phenol oxidase activity, a consecutively reduced concentration of phenolic compounds, and an increased activity of organic matter degrading hydrolases. (13,14) As a consequence, the stability of wetland carbon stores is at risk, and vast amounts of carbon will potentially be emitted back into the atmosphere, which itself will further promote climate change.

I added the bold, to cut to the chase.

Happy thoughts, no?

These feedback loops from the destruction of ecosystems are going to be hell to pay.

Note: I have begun to use the HTML codes for exponents in anticipation of the full arrival of DU4.