Skip to main content
Select Source:

Ob

Ob (ôp), river, c.2,300 mi (3,700 km) long, W Siberian Russia. With the Irtysh River, its chief tributary, it is c.3,460 mi (5,600 km) long and is the world's fourth longest river. Formed by the junction of the Biya and Katun rivers (both of which rise in the Altai range) SW of Biysk, the upper Ob flows NW, then NE past Barnaul and Novosibirsk through the W Siberian lowlands to be joined by the Tom River. The middle Ob flows northwest through the swampy forests in the Tomsk and Narym regions and then is joined by the Chulym, Ket, and Irtysh rivers. The lower Ob consists of the Great Ob and the Small Ob and flows N, then E into Ob Bay, an estuary and shallow arm (c.500 mi/800 km long and 35–50 mi/56–80 km wide) of the Arctic Ocean between the Yamal and Gyda peninsulas. The width of the Ob increases downstream to c.25 mi (40 km) near its mouth. The valley of the middle Ob is subject to flooding each spring as the thaw occurs in the upper Ob basin before the ice in the lower course of the Ob has melted. Although frozen from five to six months of the year, the Ob is an important trade and transport route; Novosibirsk, Barnaul, Kamen-na-Obi, and Mogochin are the chief ports. There is a large hydroelectric power station at Novosibirsk. The largest oil and gas deposits in Russia are found in the basin of the middle and lower Ob. Severe pollution in the lower Ob has damaged the river's formerly famous fisheries.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Ob." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 23 Feb. 2018 <http://www.encyclopedia.com>.

"Ob." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 23, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/ob

"Ob." The Columbia Encyclopedia, 6th ed.. . Retrieved February 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/ob

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

Ob

Ob River in w Siberia, central Russia. It flows nw then ne through the lowlands of w Siberia, before continuing n and then e to enter the Gulf of Ob, an arm of the Kara Sea within the Arctic Ocean. Length: 3680km (2300mi). With its principal tributary, the Irtysh, it is the seventh-longest river in the world: 5410km (3360mi).

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Ob." World Encyclopedia. . Encyclopedia.com. 23 Feb. 2018 <http://www.encyclopedia.com>.

"Ob." World Encyclopedia. . Encyclopedia.com. (February 23, 2018). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/ob

"Ob." World Encyclopedia. . Retrieved February 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/ob

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.