本底质谱  background mass spectrum

表层底质  surface substrate

草型底质  vegetation bottom

沉积物底质图  types and distributions of surface sediments map

池塘底质改良  Ponds bottom soil quality improvement

船底质量  bottom quality

底质采样  bottom characteristics sampling

底质采样器  bottom sampler

底质沉积物  bottom sediment

底质调查  bottom characteristics exploration

底质分布图  bottom sediment chart

底质分类  bottom material classification; Seafloor classification; seabed material classification; bottom sediment classification; Seabed classification; seabed discrimination; substrate composition classification

底质符号  symbol of bottom matter

底质改良  bottom characteristic improvement

底质环境  sedimental environment

底质颗粒物  substrate particulate matter

底质类型  sediment types; Sediment type; surface sediments

底质类型估计  estimation of bottom sediment type

底质硫化物  sedimental sulfide