Some phytoplankton Gained Photosynthesis Superpowers From a ‘Proton Pump’

Recommendable! 

This article is a nice example of how little we still understand of what is going on in our oceans. It also demonstrates that Global Warming is a hoax and Climate Change is a religion. One more reason why climate models are largely junk!

"... Yet the clouds of phytoplankton that fill the oceans are the major drivers of that process in nature. The plantlike single-celled aquatic microbes generate more than 50% of the oxygen in the atmosphere, and they absorb nearly half of the carbon dioxide, converting it into the glucose, fats, proteins and other organic molecules that nourish the food web of the oceans.
A recently published study ... finally pins down the source of this unparalleled photosynthetic efficiency, which has long baffled scientists. The new research found that some phytoplankton are equipped with an extra internal membrane that carries a “proton pump” enzyme that supercharges their ability to convert carbon dioxide into other substances. The enhancements due to this one protein modification seem to contribute to the production of nearly 12% of the oxygen in the air and as much as 25% of all the carbon “fixed” (locked into organic compounds) in the ocean. ..."

From the highlights and abstract:

"Highlights

• The V-type H+-ATPase (VHA) promotes photosynthesis in secondary endosymbiotic algae

• VHA around diatom plastids contributes to the carbon-concentrating mechanism (CCM)

• This VHA-mediated CCM generates at least 7% of the primary production in the ocean

• Similar VHA-CCMs in extant photosymbioses are a selectable trait for symbiogenesis

Summary

Diatoms, dinoflagellates, and coccolithophores are dominant groups of marine eukaryotic phytoplankton that are collectively responsible for the majority of primary production in the ocean. These phytoplankton contain additional intracellular membranes around their chloroplasts, which are derived from ancestral engulfment of red microalgae by unicellular heterotrophic eukaryotes that led to secondary and tertiary endosymbiosis. However, the selectable evolutionary advantage of these membranes and the physiological significance for extant phytoplankton remain poorly understood. Since intracellular digestive vacuoles are ubiquitously acidified by V-type H+-ATPase (VHA), proton pumps were proposed to acidify the microenvironment around secondary chloroplasts to promote the dehydration of dissolved inorganic carbon (DIC) into CO2, thus enhancing photosynthesis. We report that VHA is localized around the chloroplasts of centric diatoms and that VHA significantly contributes to their photosynthesis across a wide range of oceanic irradiances. Similar results in a pennate diatom, dinoflagellate, and coccolithophore, but not green or red microalgae, imply the co-option of phagocytic VHA activity into a carbon-concentrating mechanism (CCM) is common to secondary endosymbiotic phytoplankton. Furthermore, analogous mechanisms in extant photosymbiotic marine invertebrates provide functional evidence for an adaptive advantage throughout the transition from endosymbiosis to symbiogenesis. Based on the contribution of diatoms to ocean biogeochemical cycles, VHA-mediated enhancement of photosynthesis contributes at least 3.5 Gtons of fixed carbon per year (or 7% of primary production in the ocean), providing an example of a symbiosis-derived evolutionary innovation with global environmental implications."

Microbes Gained Photosynthesis Superpowers From a ‘Proton Pump’ | Quanta Magazine New research reveals how marine microbes use an extra membrane that once had digestive functions to boost their yield from photosynthesis.

The V-type ATPase enhances photosynthesis in marine phytoplankton and further links phagocytosis to symbiogenesis

The diverse and intricately shaped aquatic microbes called diatoms are extraordinarily effective at converting carbon dioxide into organic molecules through photosynthesis.

Graphical abstract