Rhodopsin & why the ocean 'dead zones' are increasing in size and number.

What's rhodopsin? a light receiving pigment in our eyes. Rhodopsin containing marine bacteria don't make oxygen & they like more acidic ocean waters which oxygen producing algae & bacteria don't like.

Rhodopsin is a vitamin A containing pigment which helps us see in dim lighting but isn’t really part of our bright light vision. Our skin cells, however, do have rhodopsin and that is why sleeping with lights on, or a street light shining in the window is bad for our circadian health. Any bits of light at night disrupt our production of melatonin.

Rhodopsin as a keyword brings up quite a few posts in my archives, this one has a section about it towards the end: Children and Fairy Tales - Is Lying Okay?, (Substack) but my copy/paste seems broken so I can’t link it. -> ??????

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The low oxygen or oxygen free areas in the ocean have been increasing in size and new ones are being discovered. The rate of increase in the size and number of these oxygen deprived areas of the ocean is unprecedented per specialists. (1)

• Originally published on earth-ocean.info Dec 10, 2019.

• Continuation from this post (deNutrients.substack).

Ocean dead zones & agricultural phosphorus.

In the ancient history of the planet's oceans were all low oxygen. Sulfur-loving bacteria do not produce oxygen and they were the most common species 2.52 billion years ago. (2) They have been found to be increasing in the low oxygen zones of the Baltic Sea. While sulfur-loving bacteria were common in the ancient ocean water, photosynthesis was still newly evolved, and there was very little oxygen in the air. (2)

Algae and other microbes or larger seaweeds and sea grass that use photosynthesis to create energy from sunshine, use carbon dioxide in the chemical reaction and release oxygen just like plants on the land do. Planting more trees on land and mangroves and sea grass along coastal regions can help remove carbon dioxide from the air and increase oxygen in the ocean or air supply.

Over the history of the planet there have been five times when many species became extinct. During three of the times of extinction an increase in sulfur using bacteria in marine waters and the resulting low oxygen level in the water was involved in the loss of species. (3)

"Biodiversity loss among marine taxa, for at least 3 of these mass extinction events (Late Devonian, end-Permian and end-Triassic), has been connected with widespread oxygen-depleted and sulfide-bearing marine water." (3)

We are seeing a sixth major extinction event. Large numbers of plants, animals, insects and other species are endangered or already extinct. Loss of oxygen in the oceans is due in part to excess agricultural chemicals reaching the ocean. The excess can cause an overgrowth of algae which then eventually run out of the seasonal increase in agricultural chemicals and die off and then decomposition bacteria which use oxygen grow in excess numbers.

Overfishing is also involved. Depleting one type of fish species can upset the balance across the food chain and lead to overgrowth of some types which then overuse nutrients leading to species die-off of other species dependent on the nutrients.

The early posts on this site are a series with inventions that already exist which might help ocean health and brainstorming ideas of mine. I am not a marine expert but am trained as a nutritionist and I care about survival of biodiversity and the planet. Human existence is also dependent on oxygen in the air and we, at a planet wide level, get about a third of our protein rich food from marine species. The series of posts are combined in this document: Oxygenating the Ocean, with fewer pictures than are included among the individual blog posts.

The Pacific Ocean at Ventura, California.

Rhodopsin containing marine bacteria don't make oxygen.

(First posted on Aug. 14, 2019)

Algae and phytoplankton make oxygen and use carbon dioxide with chlorophyll like other land plants. This also means they help us survive by providing oxygen and using up the carbon dioxide that we exhale - animals and plants live in harmony. This also means they have been helping reduce the amount of greenhouse gases which add to climate change.

Another type of bacteria common in ocean water doesn't use carbon dioxide or create oxygen. They can create energy with sunlight but not in the same way as plants do with chlorophyll, they make it with rhodopsin, a light absorbing pigment that is also found in the human eye. Rhodopsin can convert a signal perceived as light in the eye into a nerve signal which will then be interpreted by other areas of the brain as to shape or color or movement of the light signal.

The ocean has been absorbing a large amount of the carbon dioxide that human civilization creates in various ways. The increase in carbon dioxide in the ocean increases the acidity of the water which is already harming some species. As the temperature and acidity of the ocean waters increase it is possible that the rhodopsin containing bacteria may become more prevalent and chlorophyll containing microbes may become less so which could add to the risk of climate change as less carbon dioxide would be used and less oxygen would be created.

The air we breathe is in a constant cycle flowing upward with the evaporation of water from the ocean and other bodies of water, and then falling downward as rain or snow. We need our air, our atmosphere, to contain enough oxygen for our survival and for all the other animals that breathe oxygen.

• A marine microbe could play increasingly important role in regulating climate: A light-snatching bacteria may get its place in the sun and alter how oceans absorb carbon dioxide -- *less carbon dioxide could be used by chlorophyll containing marine microbes if the population of microbes shifted towards the rhodopsin containing bacteria. (sciencedaily.com)

• Marine Bacterial and Archaeal Ion-Pumping Rhodopsins: Genetic Diversity, Physiology, and Ecology, ( mmbr.asm.org).

We breathe in oxygen & exhale carbon dioxide. Plants do the opposite. Rhodopsin bacteria use light in a different way than plants, more like the way our eyes can perceive light, and don't use carbon dioxide.

Plastic found to be harmful to some oxygen creating ocean microbes.

(First posted on May 17, 2019)

The plastic pollution in the oceans is harming larger species which eat colorful pieces but can't digest it. The plastic collects in the animals’ digestive system and they eventually starve. More recently it was discovered that some microbes may also be absorbing plastic and are being harmed.

The risk to ocean and human life is in the loss of oxygen that the microbes would otherwise be adding to the atmosphere. The photosynthetic bacteria would also be part of the food supply for other marine life.

• Read more: Plastic Pollution Harms Bacteria that Produce 10 Percent of Oxygen we Breathe, (The Independent).

Ocean microbes make as much as half of the oxygen in our atmosphere. Trees in the Amazon rain-forest and elsewhere also are important oxygen producers.

Slideshow - ‘Pick up litter’ - a collection of image collages: (canva.com).

Disclaimer: Information provided for educational purposes within the guidelines of Fair Use.

References:

1. Fiona Harvey, Oceans losing oxygen at unprecedented rate, experts warn. The Guardian, Dec. 7, 2019. https://www.theguardian.com/environment/2019/dec/07/oceans-losing-oxygen-at-unprecedented-rate-experts-warn?CMP=share_btn_tw

2. Stephanie Pappas, 2.5-Billion Year Old Fossils Predate Earth's Oxygen. livescience.com, Dec. 1, 2016, https://www.livescience.com/57051-ancient-life-fossils-predate-earth-oxygen.html

3. Schobben M, Stebbins A, Ghaderi A, Strauss H, Korn D, Korte C. Eutrophication, microbial-sulfate reduction and mass extinctions. Commun Integr Biol. 2015;9(1):e1115162. Published 2015 Dec 4. doi:10.1080/19420889.2015.1115162 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802792/