@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @prefix dcterms: . @prefix grg: . @prefix iop: . @prefix ns0: . @prefix ns1: . @prefix owl: . @prefix pav: . @prefix prov: . @prefix puv: . @prefix qudt: . @prefix rdf: . @prefix rdfs: . @prefix reg: . @prefix sdo: . @prefix semapv: . @prefix skos: . @prefix sssom: . @prefix void: . @prefix xsd: . rdf:type sdo:DefinedTerm ; sdo:description "Developed in the mid-1960s (Powers and Robertson 1967), ponar grabs are used to sample coarse or fine, undisturbed sediment from the sea floor. It consists of a pair of weighted, tapered jaws held open by a catch bar across the top of the sampler. On touching the bottom, the tension bar is released, allowing the jaws to move and close. The device is activated by the release of the cable tension on the lifting mechanism when the sampler reaches the sediment. During retrieval, the tension on the cable keeps the jaws closed. It has a pair of metal side plates which prevents the sampler from falling over after the jaws' closure. Its jaws overlap to minimise sample washout during ascent. Depending on the variant (standard or petite), the sampled area can be between approx. 15-23 cm sq. (approx. 1000 - 7250 cubic metres)."@en ; sdo:inDefinedTermSet ; sdo:name "Unspecified ponar grab"@en ; sdo:termCode "SDN:L22::TOOL1214" .