UPSC Mains 2019 · GS I · Q17 · 15 marks · 250 words

How do ocean currents and water masses differ in their impacts on marine life and coastal environment ? Give suitable examples.

हिन्दी में

महासागर धाराएँ और जल राशियाँ समुद्री जीवन और तटीय पर्यावरण पर अपने प्रभावों में किस-किस प्रकार परस्पर भिन्न हैं ? उपयुक्त उदाहरण दीजिए ।

Oceanography

How a topper answered the closest question

Toppers wrote this one in a test series: “What are the major controlling forces of global ocean currents? Illustrate how ocean currents influence marine fisheries and coastal climate.”

AakritiAIR 93 · CSE 2025 · 176 wordsTheir whole copy

Opening · a definition

Ocean currents are narrow bands of fast moving ocean water that redistribute the nutrients, heat & carbon.

Body · points and prose

Diagram
Types of ocean currents (1) HOT eg. Kyoshio, gulf stream (2) COLD eg. oyoshio, canary, labrador
Diagram
[Map showing global ocean currents with labels: North Pacific Drift, California, Labrador, Gulf Stream, North Atlantic Drift, Norway, Canary, Oyoshio, Kyoshio, Chile-Peru, Humbolt, East Australian, West Australian] fig: global ocean currents

Factors influencing

1.) Heat differential → eg. Equator - warm water expands → moves towards upper latitudes eg. Kyoshio

2.) Contour of continents eg. Brazillian current

3.) Regional winds eg. Indian ocean currents change with monsoon winds

4.) Earth's rotation eg. Equitorial currents.

5.) Land & water distribution eg. Antarctic circumpolar current - continuous.

Influence of ocean currents

(A) On coastal climate

(a) Desert formation eg. Namibia due to Benguela current (Dessicating effect)

(b) Heavy rainfall eg. British type climate due to effect of warm gulf stream.

(c) Fog formation eg. Newfound-land- mixing of warm & cold current

(B) On Marine fisheries

(a) Dense fish stock in areas of warm-cold current mixing eg. near Japan

Diagram
[Arrow pointing to box labelled KUROSHIO]

(b) Areas of upwelling → nutrient increase → more fish. eg. coasts of south americas.

Close · a way forward

ocean currents are a life giving & regulating force in oceans. Its effects pattern must be carefully studied especially as climate change is weakening the Atlantic Meridional Ocean Current

How toppers approach this question, and more on its topic: open the question.

Toppers’ answers to other close questions

Source: UPSC, Civil Services (Main) Examination 2019, General Studies Paper I, Q17. The paper on upsc.gov.in. Themes and links to toppers’ answers are by UPSC Grade, not by UPSC.