A strait is a naturally formed narrow waterway running between two land masses and connecting two water larger water bodies. The Lombok Strait is located between the Indonesian islands of Lombok and Bali. It connects the Indian Ocean to the Java Sea.
Dimensions of the Lombok Strait
The Lombok Strait is 60 km long. It is widest at its northern opening where it is 40 km or 25 miles across. It is narrowest between the Lombok island and the Nusa Penida Island at its southern opening where its width is only 20 km or 12 miles. The Lombok Strait has a maximum depth of 250 m or 820 feet.
Navigation in the Lombok Strait
The Lombok Strait often acts as an alternative route for vessels like bulk carriers and supertankers transporting goods, especially oil, from Arabia to China. Since the Strait of Malacca has an average depth of only 82 feet, many ships are unable to navigate through it successfully. Vessels with the maximum tonnage that can pass through the relatively shallow Malacca Strait are called Malaccamax vessels while those exceeding this tonnage are called post-Malaccamax vessels. The latter types of vessels use the deeper Lombok Strait for passage although it requires traversing a longer route.
The Lombok Strait Allows Oceanic Water Exchange
Water exchange between the Pacific Ocean and the Indian Ocean takes place through the Lombok Strait. The Indonesian Throughflow is a major ocean current flowing through this strait that allows transport of warm, fresh water from the Pacific to the Indian Ocean. This water movement has an important role in shaping global climate.
Role of the Lombok Strait as a Boundary Between Two Biogeographical Realms
The Wallace Line is an imaginary line separating two major biogeographic realms of the world; the Indomalaya realm and the Australasian realm. Although not too far away, the islands of these two ecozones host fauna that is strikingly different. The Wallace Line is named after a Welsh explorer and scientist, Alfred Russel Wallace, who was the first to record this difference. The Lombok Strait forms part of this boundary that abruptly divides the two realms.
Today, biologists believe that the Lombok Strait is primarily responsible for the differences between animals of the Indomalaya and Australasian realms. During the Pleistocene ice age, the sea levels were significantly lower than what it is today. During that period, the Indonesian islands of Sumatra, Java, and Bali were all linked to each other and to mainland Asia. Thus, they shared Asian fauna. However, Lombok and the islands of the Lesser Sunda archipelago were separated from these islands and mainland Asia by the deep waters of the Lombok Strait. Thus, these islands were colonized by animals typical to Australasia like the marsupials.