earth science

Halomonas meridiana

Halomonas meridiana is a earth 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 Halomonas meridiana rather than just read about it. In short: Halomonas meridiana (H. meridiana) is a bacterial species discovered in 1990 in the hypersaline lakes of Vestfold Hills, Antarctica. Taxonomy Halomonas meridiana is a Gram-negative microorganism of the family Halomonadaceae.

Key takeaways

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

Reference excerpt

Halomonas meridiana (H. meridiana) is a bacterial species discovered in 1990 in the hypersaline lakes of Vestfold Hills, Antarctica.

Taxonomy Halomonas meridiana is a Gram-negative microorganism of the family Halomonadaceae. There are several known strains of this microbe including DSM 5425, ACAM 246, ATCC 49692, and CIP 104043. It shares many characteristics with other species in the same genus. H. meridiana was placed in this genus due to its halophillic nature as well as its close genomic relation to others in the same taxa. This species shares a close relationship with the known species Halomonas elongate, Halomonas halmophila, and Halomonas subglaciescola.

Characteristics/morphology Halomonas meridiana is a Gram-negative halophilic organism found in the lakes of Antarctica. It is a rod-shaped cell with rounded ends, and it has peritrichous, all over the surface, flagella. It is between 2 and 3 micrometers in length and 1 micrometer wide. This organism has an average genome currently sized 3.8 mega base pairs (Mbp) containing 56.96% GC's, or guanine and cytosine content. It has 3,864 genes of which 3,696 of those genes are protein coding. H. meridiana is a commensal marine bacteria that is found living on reef-building corals as part of their surface microbiome. It is not known to be pathogenic. Halomonas meridiana is a heterotrophic organism capable of anaerobic growth with the aid of glucose when nitrogen is not present.

Discovery In 1997, James et al. published a paper describing an organism they had discovered. It was found in the Vestfold Hills, Antarctica salt lakes, which contained many undescribed microbes including this organism. Water from the lake was placed on agar plates and incubated. After allowing time for growth, single cells were removed from colonies and grown on new agar places. After 2–4 weeks of incubation, colonies were transferred to a basal media designed to simulate an organic lake. Many species of microorganisms and several strains of what would later be identified as Halomonas meridiana were found and tested for physical and chemical characteristics using quantitative phylogenetic techniques. James et al. mapped the results of DNA base composition, salt tolerance, and temperature tolerance tests against those of other known organisms of the same family. After careful study, they determined that the organism they had found was different from the rest. They placed the organism in the genus Halomonas. In addition to Antarctica, Halomonas meridiana was also isolated from the host of organisms found living in and on coral, Acropora, across the world. The found organism was identified as Halomonas meridiana using sequences of parts of the 16S rRNA gene. The word Halomonas comes from the Greek word halos meaning "salt" and monas meaning "unit" and The word meridiana comes from the word meridian meaning "of or belonging to the south".

Importance This species helps expand our knowledge of the importance of heterotrophic bacteria that live in a symbiotic relationship with other organisms. This organism is a symbiont that lives on the surface of coral reefs. Halomonas meridiana was discovered living on the surface of the species Acropora, which are reef building coral. Halomonas meridiana also produces proteases. These metalloproteases specific to marine bacteria are important for cleavage of connective tissues as well as adhesion of detachment to mucus. The alkaline proteases are important aspects of the processes involving detergents, leather, food, and silk for consumer consumption. Halomonas meridiana was an important organism used in defining the new term, haloversatile. H. meridiana exhibits properties of both halotolerant and slightly halophilic bacteria, and as a result a new term, haloversatile, describes the salinity tolerance of this organism better than the traditional terms. Halotolerant and halophilic bacteria, like H. meridiana can also provide valuable information about species that have been adapted to the salt lakes in cold temperatures as well as retaining the ability to live in symbiosis with other organisms.

References

External links Type strain of Halomonas meridiana at BacDive – the Bacterial Diversity Metadatabase

Worked examples

Example 1 — a first encounter with Halomonas meridiana

Start with the simplest possible case. Write down what Halomonas meridiana claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth 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 Halomonas meridiana 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 Halomonas meridiana 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 Halomonas meridiana

In research: Halomonas meridiana appears in earth 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 Halomonas meridiana 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: Halomonas meridiana is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bacteria described in 1990, Gram-negative bacteria, Halophiles, so understanding it makes those chapters shorter.
In everyday life: Look for Halomonas meridiana 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 Halomonas meridiana in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Halomonas meridiana 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 Halomonas meridiana out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Halomonas meridiana in simple terms?

Halomonas meridiana (H. meridiana) is a bacterial species discovered in 1990 in the hypersaline lakes of Vestfold Hills, Antarctica. Taxonomy Halomonas meridiana is a Gram-negative microorganism of the family Halomonadaceae.

Why does Halomonas meridiana matter?

Because it connects several earth 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 Halomonas meridiana?

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 Halomonas meridiana.