According to the Maritime Zones Act 2005, natural resources refer to minerals and other non-living materials found in the subsoil and seabed and the marine organisms in a sedentary state, that is, they are unfit for movement when they are harvested or depend on water or soil movement for displacement ^[1].

Minerals present in the continental shelf

The island of Mauritius emerged from the sea about 7-10 million years ago; four volcanic episodes created the land mass that we can now see. Each phase created a different layer of minerals, starting from the oldest to the most recent: ^[2]

• the Breccia series – basalt oceanites (mineral olivine)
• the Old lava series – picrite basalt (rich in the mineral olivine), olivine basalt, hawaites (rich in andesite pyroxene), basalt rich in feldspars, andesites, hawaites, mugearites (oligoclase)
• the Early lava series – olivine basalt
• the Recent lava series – olivine basalt

Resources found on the ocean floor

Deep-sea drilling of the ocean floor reveals the presence of polymetallic nodules in the Indian Ocean. It is estimated that these nodules have a coverage of about 10-15 million km², weighing about 1.5×10¹¹ tonnes, across the whole of the Indian Ocean ^[3].

Mauritius is located in the West Indian Ocean Basin; geomorphological analyses of the seabed near Mauritius report numerous seamounts and guyots (flat based mountains), trenches and fractures ^[2]. All these different structures influence the type of minerals that can possibly be found in the areas close to Mauritius.

1. Polymetallic nodules – they are rich in manganese and are located in the sediment of the deep sea; important metals include copper, nickel, cobalt.
2. Ferromanganese crust – 11% of the total ferromanganese crust minerals is evaluated to be in the Indian Ocean. They usually form on the surface and flanks of seamounts. The crust is a source of cobalt, nickel, manganese, titanium, copper, cerium and trace metals tungsten, molybdenum, platinum and tellurium.
3. Polymetallic sulphides – hydrothermal polymetallic sulphides are usually located around volcanic structures in mid-ocean ridges, island arcs or back-arc spreading zones. These are the black smoker zones pilling up important metal ores of copper, lead, zinc, gold, silver, germanium, bismuth, indium and selenium ^[4].

Recently, new discoveries suggest that Mauritius may be lying on a part of an oceanic crust or microcontinent called ‘Mauritia’. The land mass broke off Madagascar during plate separation 65 million years ago but finally sunk to the bottom ^[5]. Being made of continental granite, mineral content in this layer could be fascinating. Detrital zircons have already been found in the granitic rock as lava-plumes have brought minerals to the surface ^[6].

Sedentary marine organisms in the Mauritian waters

Shallow water species that have been identified include the:

• annelida (worms; ⁓42 species),
• arthropoda (crustaceans, organisms with exoskeleton; about ⁓660 species),
• ascomyta (fungi; ⁓74 species),
• bacillariophyta (microalgae; 1 species),
• basidiomycota (fungi; 2 species),
• brachiopod (organisms with upper and lower valves; 3 species),
• chaetognatha (arrow worms; 18 species),
• chlorophyta (green algae; about ⁓180 species),
• cnidaria (jellyfish, coral polyps; ⁓450 species),
• cyanophycota (blue green algae; ⁓76 species),
• deuteromycotina (imperfect fungi; 14 species),
• echinodermata (organisms with radial symmetry like starfish; ⁓170 species),
• echuira (spoon worms; 2 species),
• ectoprocta (filter feeders; ⁓40 species),
• hemichordate (worms; 2 species),
• heterokontophyta (algae; 1 species),
• magnoliophyta (flowering plants; 10 species),
• mollusca (molluscs; ⁓2050 species),
• nemertea (ribbon worms; 5 species),
• phaetophyta (brown algae; ⁓85 species),
• phyllophoridae (sea cucumber; 1 species),
• porifera (sponge; ⁓80 species),
• rhodophyta (red algae; ⁓species) and
• sipuncula (worms; 17 species) ^[7].

To date, 8,000 sedimentary marine organisms have been documented in the Western Indian Ocean shallow waters ^[8]. A comprehensive study of the marine creatures on the ocean floor is still to be made as deep sea exploration is quite difficult to undertake.

In 2011, 6 new sea creatures were discovered in vents in the South West Indian Ocean floor ^[9]. More recently, oil and gas reserves have been detected near Seychelles ^[10]. All these discoveries suggest that the deep ocean floor around Mauritius may be hiding a lot of amazing treasures.

References:

1. United Nations. United Nations Convention on the Law of the Sea. [pdf]. Available at http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf [Accessed 08.03. 2018]
2. Saddul, P. (2002). Mauritius, A Geomorphological Analysis. Moka, Mauritius: MGI, pp 32,33; pp8
3. Siddiquie, A.R., et al. (1984). Superficial mineral resources of the Indian Ocean. Deep Sea Research Part A. Oceanographic Research Papers. Vol 31 (6-8), pp763-812. Available at https://www.sciencedirect.com/science/article/pii/0198014984900402 [Accessed 08.03.2018]
4. Investigation of marine mineral resources. [online] Available at https://www.bgr.bund.de/EN/Themen/MarineRohstoffforschung/Erkundung-mariner-mineralischer-Rohstoffe/erkundung-mariner-mineralischer-rohstoffe_node_en.html [Accessed 08.03.2018]
5. Geological Report. (2015). Opportunity assessment for the development of geothermal energy in Mauritius. [pdf]. Milano, Italy: ELC-Electroconsult. Available at http://publicutilities.govmu.org/English//DOCUMENTS/01_GEOLOGICAL_REPORT.PDF [Accessed 08.03.2018]
6. Torsvik, T.H., et al. (2013). A precambrian microcontinent in the Indian Ocean. Nature Geoscience, [online] Vol 6, p 223–227. Available at https://www.nature.com/articles/ngeo1736 [Accessed 10.03.2018]
7. Database of Marine Organisms of Mauritius. (2007). Mauritius Oceanography Institute. [online]. Available at http://moi.gov.mu/marinedb[Accessed 23.03.2018]
8. Richmond, M.D. The marine biodiversity of the western Indian Ocean and its biogeography: How much do we know? VLIZ, Platform for marine research. [pdf] Available at vliz.be/imisdocs/publications/246534.pdf [Accessed 08.03.2018]
9. Lewis, D. (2016). Six new deep sea creatures just discovered at site slated for underwater mining. [online]. com. Available at https://www.smithsonianmag.com/smart-news/six-new-species-sea-creatures-discovered-region-slated-underwater-mining-180961480/ [Accessed 08.03.2018]
10. Kabukuru, W. (2014). Oil and gas finds lift western Indian Ocean prospects. [online] Available at http://www.seychellesnewsagency.com/articles/640/Oil+and+gas+finds+lift+western+Indian+Ocean+prospects [Accessed 08.03.2018]