Table 2 Plume vertical extent and dilution factors measured during PLUMEX field studies and predicted by the DP1 and DP2 dynamic plume models.

From: Extent of impact of deep-sea nodule mining midwater plumes is influenced by sediment loading, turbulence and thresholds

Plume parameters

Saltwater plume 1

CCFZ sediment plume

Saltwater plume 2

Commercial plume

Maximum dynamic plume vertical extent (m)

PADS: 42–50

DP1 model: 35

PADS: 14–18

DP1 model: 15

PADS: 14–18

DP1 model: 15

DP1 model: 79 (110)

Near field neutral buoyancy depth (m)

DP2 model: 105

Epsilometer: 72–74

DP2 model: 69

Epsilometer: 72–74

DP2 model: 68

DP2 model:

1063 (1090)

Near field dilution factor (epsilometer; 30 m away from the discharge)

DP2 model: 118

Two strongest signals:

Tracer: 73 and 83

Sediment: 77 and 86

DP2 model: 110

Two strongest signals

Tracer: 64 and 80

DP2 model: 98

DP2 model: 200 (280)

Intermediate field dilution factor (CTD tow-yo; 500 m away from the discharge location and 118 minutes after the start of the discharge)

N/A

Two strongest signals:

Tracer: 283 and 517

Sediment: 282 and 515

Typical signal:

Tracer: 1114–2538

Sediment: 1094–2725

N/A

N/A

  1. The sediment concentration was measured by the turbidity sensor and the tracer concentration by the fluorometer, both mounted on the epsilometer. For the commercial-scale plume, current velocities of 5 (and 10) cm s−1 are applied for the dynamic plume model calculations.