Nanobdellati

Some tiny life forms are very small. They belong to a group called Nanobdellati. These living things are smaller than other tiny life.

Many of them need help to live. They live close to other tiny life. This help gives them what they need. They cannot make everything on their own.

They live in many strange places. Some live in very hot water. Others live in very salty water. Some even live in old mines.

It is hard to find them. They are often hidden in deep water. Scientists must look very closely to see them.

These tiny things are quite amazing. They find ways to live anywhere!

Nanobdellati is a kingdom of tiny living things called archaea. These archaea are very small. Scientists call them nanoarchaea because of their tiny size.

Many of these tiny life forms have small genomes. A genome is the set of instructions for a living thing. Because their instructions are small, they cannot make everything alone. Many are episymbionts. This means they live on or near other life forms to get help. They rely on other microbes to meet their needs.

These tiny creatures live in many different places. Some like very hot water. Others live in very salty water. Some live in acid from old mines.

Finding them is a big challenge. They are often found in deep groundwater or lake sediments. They are rarely found in the open ocean. Scientists use special ways to study them. Some groups, like the ARMAN archaea, were found in mines in the USA. Others were found near Iceland. Scientists are still learning how they all fit together.

Nanobdellati is a special kingdom of tiny living things called archaea. These microbes are so small that scientists call them nanoarchaea. They are much smaller than other types of archaea. This small size is a very important part of who they are. Many of these tiny creatures have very small genomes. A genome is the set of instructions a living thing needs to work. Because their instructions are small, they have limited ways to make what they need to live.

To survive, many Nanobdellati act as episymbionts. This means they live on or near other living things to get help. They often rely on other microbes to provide what they cannot make themselves. Some of them can live on their own. Those that live freely are often fermentative and aerobic heterotrophs. This means they get energy by breaking down organic matter. Most of them live without oxygen, which is called being anaerobic. They are very hard to grow in a lab.

Scientists first proposed the kingdom Nanobdellati in 2013. Before that, many groups were known by the name DPANN. This name is an acronym for the first five groups found. These groups are Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota. Later, scientists found more groups like Woesearchaeota and Pacearchaeota. In 2017, a group called Altiarchaeota was also added to this superphylum. Researchers like Rinke and others have worked hard to name them.

These tiny organisms live in many extreme places. Some live in hot water near Iceland. Others live in very salty water or very acidic water. For example, Parvarchaeota were found in acidic mine drainage in the USA. These are often called ARMAN archaea. Some groups are found in lake sediments or groundwater. Diapherotrites were found in groundwater from a gold mine in the USA. It is a hard job to find them because they are not often in the open ocean.

Scientists are still studying how Nanobdellati fits into the tree of life. There is a big debate about their family history. Some tests suggest they belong to a group called Euryarchaeota. Other tests suggest they might be polyphyletic. This means they might actually come from many different places. This happens because they have a high mutation rate. This can cause something called long branch attraction in scientific studies. This makes them look related even if they are not.

Nanobdellati is a unique kingdom of archaea that was first proposed in 2013. These organisms are often called nanoarchaea or ultra-small archaea because of their nanometric size. They are significantly smaller than most other types of archaea. This tiny size is directly linked to their very small genomes. A genome is the complete set of genetic instructions a cell needs to function. Because their genomes are so small, these microbes have limited catabolic capacities. This means they have a restricted ability to break down substances for energy.

Many members of Nanobdellati survive by being episymbionts. An episymbiont is an organism that lives on the surface of another organism. These microbes often depend on a symbiotic or parasitic association to stay alive. They lack the central biosynthetic pathways needed to make nucleotides, amino acids, and lipids. Because they cannot make these essential building blocks, they must rely on other microbes. For example, the ARMAN archaea depend on neighbors to meet their biological requirements. However, some Nanobdellati can live freely. These free-living forms are typically fermentative and aerobic heterotrophs. Most of the group remains anaerobic, meaning they live without oxygen, and they are difficult to cultivate in laboratories.

Scientists often use the acronym "DPANN" to describe this group. This name comes from the initials of the first five groups discovered. These include Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota. Over time, more groups have been added to this superphylum. Woesearchaeota and Pacearchaeota were discovered and proposed later. In 2017, the phylum Altiarchaeota was also placed within the DPANN superphylum. The classification of these groups is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and the NCBI.

The different phyla within Nanobdellati live in many different environments. Their lifestyles and metabolisms vary widely. Nanoarchaeota were the first to be discovered in 2002. They were found in a hydrothermal source near the coast of Iceland. These organisms live as symbionts of other archaea. Parvarchaeota and Micrarchaeota were discovered in 2006. They live in acidic mine drainage from a mine in the United States. These are provisionally called ARMAN, which stands for Archaeal Richmond Mine acidophilic nanoorganisms. Other groups like Nanohalarchaeota thrive in environments with high salinity.

Finding these microbes is a difficult task for researchers. They are rarely found in the open ocean or on the ground. Some have been detected in nitrate-rich groundwater. Others have been found on the water surface, but not below it. Aenigmarchaeota have been located in wastewater from mines and hot spring sediments. Woesearchaeota and Pacearchaeota are found in the sediments and surface waters of lakes and aquifers. These groups often abound in saline conditions. This wide distribution shows how diverse the kingdom can be.

There is a major scientific debate regarding the phylogeny of Nanobdellati. Phylogeny is the study of the evolutionary history and relationships of organisms. Some analyses suggest Nanobdellati might be the first divergent clade of archaea. However, other studies suggest they belong to the Euryarchaeota. It is even possible that they are polyphyletic. A polyphyletic group is one where the members do not share a single common ancestor. Instead, they might occupy various different positions within the Euryarchaeota. This uncertainty exists because these phyla have a high mutation rate.

This high mutation rate can cause a scientific error called long branch attraction (LBA). LBA is an artifact where lineages are grouped together artificially at the base of a phylogenetic tree. This happens even if the lineages are not actually related. Because of this, the exact placement of Nanobdellati remains a subject of intense study. Scientists continue to use genomic comparisons to understand these evolutionary origins. The relationship between Nanobdellati and other groups, such as the Altiarchaeota, is still being debated. Understanding these tiny organisms helps us learn more about the diversity of life on Earth.