Nitrosopumilales

Overview

Illustration of a virus from the Thaspiviridae family

Nitrosopumilales is an order of the class Nitrososphaeria within the phylum Thaumarchaeota. These microorganisms are a group of ammonia-oxidizing archaea (AOA) that play a crucial role in the global nitrogen cycle by converting ammonia into nitrite, a process known as nitrification.

Taxonomy

The order Nitrosopumilales was established to classify a distinct lineage of archaea that are primarily found in marine environments. The members of this order are characterized by their ability to oxidize ammonia at low concentrations, which is a key ecological function in the ocean's nitrogen cycle.

Families and Genera

Nitrosopumilales includes several families and genera, with the most well-known being the genus Nitrosopumilus. This genus includes species such as Nitrosopumilus maritimus, which was one of the first ammonia-oxidizing archaea to be isolated and studied in detail.

Ecology

Diagram showing the structure of a Thaspiviridae virus

Members of the Nitrosopumilales are predominantly found in marine environments, including open oceans, coastal waters, and deep-sea ecosystems. They are also present in some terrestrial environments, such as soils and hot springs. These archaea are adapted to thrive in environments with low ammonia concentrations, which makes them particularly important in oligotrophic (nutrient-poor) conditions.

Role in the Nitrogen Cycle

Nitrosopumilales contribute significantly to the nitrogen cycle by oxidizing ammonia to nitrite, which is a critical step in the process of nitrification. This conversion is essential for the recycling of nitrogen in marine ecosystems, influencing both primary productivity and the global nitrogen budget.

Genomic Features

The genomes of Nitrosopumilales species are relatively small compared to other archaea, reflecting their specialized metabolic capabilities. Genomic studies have revealed the presence of genes encoding for ammonia monooxygenase, the enzyme responsible for the oxidation of ammonia, as well as other genes involved in nitrogen metabolism.

Related Pages

• Thaumarchaeota
• Nitrososphaeria
• Ammonia-oxidizing archaea
• Nitrification