Deep Sea Minerals - Vol 2 - Manganese Nodules

2.1

Habitats and biodiversity in manganese nodule regions

Manganese nodules occur widely on the vast, sediment-cov- ered, rolling plains of the abyssal ocean (an environment that occupies more than half of Earth’s surface) at depths of about 4 000 to 6 500 m. The nodules are especially widespread in the North and South Pacific basins at latitudes greater than 10° N and S (McMurtry 2001). Where nodules occur, they are typically the predominant hard substrate, covering up to 75 per cent of the sea-floor. Manganese nodules vary in size, abundance, and

surface texture, producing habitat heterogeneity, or diversity, at the sea-floor on landscape (km) scales for both hard-bottom and soft-sediment biotas, or life forms. This habitat heteroge- neity leads to variations in faunal (animal) abundance and com- munity structure. Different communities live in sediments with heavy and light nodule cover, and distinct groups of animals live on the nodules themselves (Mullineaux 1987; Veillette et al . 2007a and b; Miljutina et al . 2010).

Depth: 4 000 - 6 500 metres

Very low ux of particulate Organic Carbon

V e r y w e a k b o t t o m c u r r e n t s ( l e s s t h a n 5 c m / s )

Very low bottom water temperature O

Note: nodules not on scale

Sediments

Living on the surface and above

Living on the nodules

Living in the sediments

Macrofauna

Microfauna

Meiofauna

Megafauna

Figure 15 Habitats and biodiversity in nodule regions. [GRID Arendal).

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