Are we part of a holobiont? (7/29/2023)

If you haven’t been living in a hole in the ground, you must have heard about the word or concept called microbiome. Microbiome is defined as the community of microorganisms that exists in a particular environment. These can include fungi, bacteria, other singular cellular organisms and even viruses. When we look at us humans these are our gut bacteria and everything else that is down or better in there. Moreover, it seems that even our hands, our body and every other part of our body have a unique microbiome. The microbiome on our left hand might even differ from that on our right hand. Being a baker, I listened to a podcast on sourdough breads and it seems that every sourdough baker has a microbiome on their hands that is unique to the sourdough starter they use.

The microbiome seems to be responsible for a lot of things in our life including gut health; our resistance to diseases; dementia at older age; and even our mental health. It appears we have more (micro)organisms in our gut microbiome than cells in our body. We are what is considered by some scientists a holobiont.

A holobiont is defined as an assemblage of a host and the many other species living in or around it, which together form a discrete ecological unit. In other words, we as individual humans and our microbiome together are holobionts. There is still some controversy about this concept of holobiont and even my spell checker does not know the word yet.

What medical science is slowly telling us is that if our microbiome is off, we get in all kinds of trouble. The simple issue maybe diarrhea or other stomach upset. It may include weight loss or conversely in folks who suffer from obesity. As I mentioned above, it seems that Alzheimer can even be linked to our microbiome being out of balance, or at least it can excel the mental decline or onset of dementia in some. We can change our microbiome with the food we eat, and this is where the concept of not “not every calorie is the same” comes from. We are hopefully also all learning about probiotics (fermented foods rule), prebiotics, and now even post-biotics. All parts of a healthy nutrition that is good for gut health. Folks with CDIF (or Clostridium difficilus), a very virulent bacterial infection may even require a fecal or poop transplant to get a healthy microbiome from someone else implanted in their gut. Which might be the only way to shake this disease.

Anyway, I want to stop here, and write more about the concept of holobiont. This idea, an assemblage of a host and other species living together in some form of harmony is interesting to me and to a lot of scientists. I think this is what makes it so darn controversial. One of the reasons is that if we look at it on a large scale, we can look at an island or even the Earth as a holobiont as well, and that everything living on this earth are part of that assemblage. Ah, we are quickly entering the world of Gaia and I think this is where the whole concept of holobiont runs into trouble. Gaia is more metaphysical; it seems to be more the believe in the divine personification of the Earth and the matriarch of all things in existence. Modern pagans believe Gaia is the Earth and she is the spiritual embodiment of the Earth. In other words, scientist that consider the Earth a holobiont are skating on thin ice and can be accused of being pagans or some other form of religious heretics.

However, the concept is an interesting one. Like our gut with diarrhea, the earth can also get or be out of balance when the assemblage of species gets out of balance. An interesting concept isn’t it? It is somewhat Malthusian, but I am beginning to believe that we are exceeding the carrying capacity of the earth; the carrying capacity is the number of individual humans the earth can safely handle before things go awry. In my eyes, we humans could be considered the E. coli of even CDIF of the Earth. There are just too many of us, and the Earth is sick! That is what I think we are seeing, global warming, the weather is going bonkers; everything seems out of balance. Even today there was a report that the gulf stream that keeps western Europe warm may be diminishing and put Europe in an eventual deep freeze. Strange days indeed! Have we reached the point of no return? I don’t know, only time will tell.

During our hike last week we encountered communities like this.  Although not a holobiont, the lichen on the rock are a perfect union of algae and fungi living together in perfect harmony.  In addition I just loved the community of plants.  This was in Grayson Highland State Park.