Describe the various factors that influence ocean currents and discuss their multi-dimensional impact. (15 marks, 250 words)

Factors influencing ocean currents.

(a) Wind pattern - planetary winds like roaring 40s, trade winds drive surface water to move. Eg: Peru current, Benguela current

(b) Coriolis force - force from earth's rotation. Eg: equatorial currents.

(c) Temperature & salinity gradient cause difference in density causing currents. Eg: gulf stream

(d) coastal topography Eg: Hudson bay current.

(e) counter currents to balance water displacements Eg: counter equatorial current.

[World map diagram showing major ocean currents: Labrador, Canary, Gulf, Equatorial counter current, Benguela, Indian Ocean current, Oyashio, Kuroshio, West wind drift, Peru current]

Multidimensional Impact of oceanic currents:-

-i- Areas where ocean currents meet i.e. warm & cold make up for great fishing grounds hence support fish industry.

Eg: Labrador (cold) - Gulf stream (warm) - Canadian fishing industry

Oyashio - Kuroshio current - in Japan coast

-ii- International shipping lanes are impacted by current (sailing with current -> ↓ fuel cost)

-iii- Helps as strategic advantage. Eg: Indian ocean current helps navy sailing.

-iv- Impacts local weather condition. Eg: Californian cold current causes Mohave desert in USA.

Hence, ocean currents have a multidimensional impact.

Due to global warming, glaciers are melting causing slower oceanic currents impacting fauna and industry. Also, illegal waste dumping affects current, Eg: central atlantic garbage patch.