English to Spanish Tech/Engineering Geology Marine surveys

Necesito la primera parte de este término, entiendo que box core sampling es toma de muestras mediante sacatestigos (box core) y el grab sampling he podido ver que era algo asi como muestras de agarre pero no lo tengo muy claro, para sondeos marinos ver abajo gracias, en este contexto

Particle Size Distribution
Analytical results of all the processed samples (Appendix I and summarised in Table 14), along with observations made within the field, indicated that the seabed within the Tyra survey area was relatively homogeneous around a sandy coarse SILT, with some silty very fine SAND fractions.Analogue survey techniques using backscatter (as an indicator of sediment reflectivity) also indicated that the sediment type remained reasonably consistent throughout the survey area.
Seabed photography was performed at all environmental locations apart from ENV_16and grab/box core sampling was performed at all environmental locations.
For the most part, all sediments gave similar particle size distributions relating to poorly sortedsandy coarse SILTS throughout with a mean particle size of 35 to 71µm at all sites except ENV_15b which recorded 103µm (Figure 7).