New Wave Media

February 26, 2021

Undisturbed Benthic Sampling with Multiple Corers

  • (Photo: OSIL)
  • (Photo: OSIL)
  • (Photo: OSIL) (Photo: OSIL)
  • (Photo: OSIL) (Photo: OSIL)

Traditional benthic samplers such as box corers must be deployed with sufficient momentum to ensure penetration of the seabed. This creates a bow wave that will disrupt the surface layer of the seabed before the corer is able to collect a full sample.

The multiple corers available from seabed sampling experts Ocean Scientific International Ltd (OSIL) are able to overcome the traditional difficulties associated with benthic sampling and collect truly undisturbed sediment samples. The multiple corers are landed on the seabed at slow speed which, in combination with the minimal footprint of the corer, prevents a bow wave from forming and driving away the delicate flocculant material that forms on the surface layer of the seabed.

The penetration speed is controlled by a hydrostatically damped piston and central weight system which enables up to 12 core tubes to be slowly driven into the seabed at a consistent rate. The core tubes are automatically sealed top and bottom immediately on commencement of the recovery process (using a hydrostatic seal at the top, and a mechanical seal at the bottom), capturing a pristine sediment sample together with the overlying supernatant water, and allowing the corer and samples to be rapidly recovered to the vessel without compromising the integrity of the sample. The transparent cast acrylic core tubes are removed individually and can be subsampled immediately or treated/preserved for later study.

The delicacy of sampling of these corers has meant that their standard use is specified in a number of Environmental Impact Assessment studies, such as the exploration and exploitation licensing procedures for marine mineral extraction, in addition to academic studies of the microbiology and flora/fauna of shelf and deep-sea sediments and analysis of the associated processes.

The multiple corers can be configured to accommodate varying numbers of core tubes, and delivery times for the corers and spares kept low, meaning even last-minute cruises are well supported, with systems remaining in constant use for many years.

OSIL have an abundance of global experience in the construction and operation of a wide range of sediment coring equipment, including the industry standard multi corer and the unique giant piston corer which is capable of achieving cores up to 60m in length. OSIL also offer a full design, build and implementation service for all of their heavy offshore equipment.

Marine Technology Reporter takes a deep dive into Oceanography in its February 2021 eMagazine edition, including insights on the GO-BGC Array Project to Monitor Ocean Health.
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