21.   Out on the ocean, scallop boats that spent seven months scraping the sea bottom for scraps of wreckage have been replaced by sport fishing boats.

22.   Some Japanese experts speculate that the ships are mapping the offshore sea bottom, data of great value to the military.

23.   The calcium-carbonate crystals would have piled up in uneven bands along the sea bottom.

24.   The blooms eventually sink in thick carpets to the sea bottom, where they suck dissolved oxygen from the water and leave dead zones.

25.   The field extends into the sea bottom and is distorted slightly if any metal is present.

26.   The pictures, provided by the US Geological Survey, showed how fishing boats that drag their nets along the sea bottom catch far more than fish.

27.   The sea bottom there has been widely stained by contamination after a century of unfettered dumping.

28.   The sand matched the sand found on the present-day beaches of Abukir and not the silt that subsequently covered the sea bottom.

29.   The work requires heavy duty equipment that can withstand high seas, shifting sea bottoms and hazardous ice.

30.   There appeared to have been an explosion in the torpedo compartment in the nose of the submarine, sending it crashing to the sea bottom, Admiral Kuroyedov said.