science

Nitrososphaeria

Nitrososphaeria is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nitrososphaeria rather than just read about it. In short: Nitrososphaeria (previously phylum Nitrososphaerota or Thaumarchaeota) is a class of Archaea under the phylum Thermoproteota. The first species, Cenarchaeum symbiosum, was discovered in 1996 and was found to have a genome distinct from other known archaea at the time; hence, it was classified as a separate phylum.

Key takeaways

Nitrososphaeria belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nitrososphaeria to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nitrososphaeria from memory before moving on to harder problems.

Reference excerpt

Nitrososphaeria (previously phylum Nitrososphaerota or Thaumarchaeota) is a class of Archaea under the phylum Thermoproteota. The first species, Cenarchaeum symbiosum, was discovered in 1996 and was found to have a genome distinct from other known archaea at the time; hence, it was classified as a separate phylum. A decade later, three ammonia-oxidizing archaea were described, Nitrosopumilus maritimus, Nitrososphaera viennensis, and Nitrososphaera gargensis. Genome analysis in 2010 revealed that C. symbiosum and the three archaea are genetically of the same group. Taxonomic reassessment in 2021 merged the archaeal group to the phylum Thermoproteota. Most species of Nitrososphaeria are chemolithoautotrophic ammonia-oxidizers and may play important roles in biogeochemical cycles, such as the nitrogen cycle and the carbon cycle. Metagenomic sequencing indicates that they constitute ~1% of the sea surface metagenome across many sites. The lipid crenarchaeol has been found only in Nitrososphaeria, making it a potential biomarker for the class. Nitrososphaeria-derived membrane-spanning tetraether lipids (glycerol dialkyl glycerol tetraethers; GDGTs) from marine sediments can be used to reconstruct past temperatures via the TEX86 paleotemperature proxy, as these lipids vary in structure according to temperature. Because most Nitrososphaeria seem to be autotrophs that fix CO2, their GDGTs can act as a record for past Carbon-13 ratios in the dissolved inorganic carbon pool, and thus have the potential to be used for reconstructions of the carbon cycle in the past.

Taxonomy In 1996, biologists at the University of California discovered archaea present in a sponge (Axinella sp.) which they had collected from the offshore of Santa Barbara. Genetic analysis showed that the archaea was different but related to Crenarchaeota, the major group of archaea known at the time. As a distinct species, it was named Cenarchaeum symbiosum. Further studies based on ribosomal RNA genes and DNA polymerase began to indicate that the archaea was not closely related to Crenarchaeota. In 2005, a team of German and American biologists at the University of Washington discovered ammonia-oxidizing archaea from various water sources around Seattle and gave the name Nitrosopumilus maritimus. It was classified under the phylum Crenarchaeota. Another related ammonia-oxidizing archaea, Nitrososphaera gargensis, was discovered in 2008 from Siberian Garga hot spring. By then, C. symbiosum was established as capable of oxidizing ammonia. Genome sequence showed that the group differ significantly from other members of the hyperthermophilic Crenarchaeota . Two phyla of archaea were recognized: Crenarchaeota and Euryarchaeota. Since the genetic difference of the ammonia-oxidizing archaea was huge from member of the two existing phyla, a third phylum Thaumarchaeota was introduced in 2008. The classification was based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. In 2014, Nitrososphaera viennensis was discovered from a garden soil in Vienna, Austria, for which Michaela Stieglmeier and her colleagues created the taxonomic hierarchy, family Nitrososphaeraceae, order Nitrososphaerales and class Nitrososphaeria. International Code of Nomenclature of Prokaryotes (ICNP, Prokaryotic Code), Aharon Oren and George M. Garrity fomralized in 2021 the phylum as Nitrososphaerota for the ammonia-oxidizing archaea, since Stieglmeier's classification was the first valid publication. At the same time, a team of Australian scientists led by Christian Rinke and Philip Hugenholtz published a new classification on archaea, in which they merged Crenarchaeota and Nitrososphaerota (in fact the entire TACK superphylum) into the phylum Thermoproteota, thereby demoting the phylum to the class level.

Classification and diversity The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)

Class Nitrososphaeria Stieglmeier et al. 2014 [Conexivisphaeria Kato et al. 2020] ?"Cenoporarchaeum" corrig. Zhang et al. 2019 ?"Candidatus Giganthauma" Muller et al. 2010 ?"Candidatus Nitrosodeserticola" Hwang et al. 2021 Order "Geothermarchaeales" Adam et al. 2022 Family Geothermarchaeaceae Adam et al. 2022 "Candidatus Geothermarchaeum" Adam et al. 2022 "Candidatus Scotarchaeum" Adam et al. 2022 Order PSMU01 Family PSMU01 "Candidatus Australarchaeum" Herbold et al. 2024 Order Conexivisphaerales Kato et al. 2020 Family Conexivisphaeraceae Kato et al. 2020 Conexivisphaera Kato et al. 2020 Family "Thermosulfuridaceae" Chang et al. 2026 [UBA164] "Acidarchaeum" Chang et al. 2026 [JAJZYL01] ?"Thermosulfuris" Chang et al. 2026 Order "Methylarchaeales" Ou et al. 2022 Family Methylarchaeaceae Hua et al. 2019 ?"Candidatus Methylarchaeum" Hua et al. 2019 ?"Candidatus Methanotowutia" Ou et al. 2022 Order "Nitrosocaldales" de la Torre et al. 2008 Family "Nitrosocaldaceae" Qin et al. 2016 "Candidatus Nitrosocaldus" de la Torre et al. 2008 "Candidatus Nitrosothermus" Luo et al. 2021 Order "Nitrosomirales" Zheng et al. 2024 Family "Nitrosomiraceae" Zheng et al. 2024 "Candidatus Nitrosomirus" Zheng et al. 2024 [UBA213] Order Nitrososphaerales Stieglmeier et al. 2014 Family "Gagatemarchaeaceae" Sheridan et al. 2023 "Candidatus Gagatemarchaeum" Sheridan et al. 2023 ?"Candidatus Subgagatemarchaeum" Sheridan et al. 2023 [Fn1; IMG2558309099] Family Nitrososphaeraceae Stieglmeier et al. 2014 "Candidatus Nitrosobungeria" Tan et al. 2026 [TH5893] "Candidatus Nitrosocosmicus" Lehtovirta-Morley et al. 2016 "Candidatus Nitrosomicrobium" Tan et al. 2026 [TA-21] "Candidatus Nitrosopolaris" Pessi, Rutanen & Hultman 2022 ?"Candidatus Nitrososappho" Singleton et al. 2025 Nitrososphaera Stieglmeier et al. 2014 Order Nitrosopumilales Qin et al. 2017 Family Nitrosopumilaceae Qin et al. 2017 "Cenarchaeum" DeLong & Preston 1996 Nitrosarchaeum corrig. Jung et al. 2018 "Candidatus Nitrosoabyssus" Garritano et al. 2024 ?"Candidatus Nitrosokoinonia" Glasl et al. 2023 "Candidatus Nitrosomaritimum" Zhao et al. 2024 "Candidatus Nitrosopelagicus" Santoro et al. 2015 Nitrosopumilus Qin et al. 2017 ?"Candidatus Nitrosospongia" Moeller et al. 2019 Nitrosotalea Lehtovirta 2024 "Candidatus Nitrosotenuis" Li et al. 2016

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Nitrososphaeria

Start with the simplest possible case. Write down what Nitrososphaeria claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nitrososphaeria before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nitrososphaeria ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nitrososphaeria

In research: Nitrososphaeria appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nitrososphaeria in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nitrososphaeria is common in secondary-school and first-year university syllabi. It links to neighbouring topics Archaea classes, Thermoproteota, so understanding it makes those chapters shorter.
In everyday life: Look for Nitrososphaeria outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Nitrososphaeria in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nitrososphaeria means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nitrososphaeria out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nitrososphaeria in simple terms?

Why does Nitrososphaeria matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nitrososphaeria?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nitrososphaeria.