William Beebe in the context of New York Zoological Society

In the deep ocean, marine snow (also known as "ocean dandruff") is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below, which is referred to as the biological pump. Export production is the amount of organic matter produced in the ocean by primary production that is not recycled (remineralised) before it sinks into the aphotic zone. Because of the role of export production in the ocean's biological pump, it is typically measured in units of carbon (e.g. mg C m d). The term was coined by explorer William Beebe as observed from his bathysphere. As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthetic activity and ocean currents. Marine snow can be an important food source for organisms living in the aphotic zone, particularly for organisms that live very deep in the water column.

The Gonostomatidae are a family of mesopelagic marine fish, commonly named bristlemouths, lightfishes, or anglemouths. It is a relatively small family, containing only eight known genera and 32 species. However, bristlemouths make up for their lack of diversity with relative abundance, numbering in the hundreds of trillions to quadrillions. The genus Cyclothone (with 13 species) is thought to be one of the most abundant vertebrate genera in the world.

The fossil record of this family dates back to the Eocene epoch. Living bristlemouths were discovered by William Beebe in the early 1930s and described by L. S. Berg in 1958. The fish are mostly found in the Atlantic, Indian, and Pacific Oceans, although the species Cyclothone microdon may be found in Arctic waters. They have elongated bodies from 2 to 30 cm (0.79 to 11.81 in) in length. They have a number of green or red light-producing photophores aligned along the undersides of their heads or bodies. Their chief common name, bristlemouth, comes from their odd, equally sized, and bristle-like teeth. They are typically black in color which provides camouflage from predators in deep, dark waters. They mainly feed on zooplankton and small crustaceans due to their small size.

The Bathysphere (from Ancient Greek βαθύς (bathús) 'deep' and σφαῖρα (sphaîra) 'sphere') was a unique spherical deep-sea submersible which was unpowered and lowered into the ocean on a cable, and was used to conduct a series of dives off the coast of Bermuda from 1930 to 1934. The Bathysphere was designed in 1928 and 1929 by the American engineer Otis Barton, to be used by the naturalist William Beebe for studying undersea wildlife. Beebe and Barton conducted dives in the Bathysphere together, marking the first time that a marine biologist observed deep-sea animals in their native environment. Their dives set several consecutive world records for the deepest dive ever performed by a human. The record set by the deepest of these, to a depth of 3,028 ft (923 m) on August 15, 1934, lasted until it was broken by Barton in 1949 in a vessel called Benthoscope.

The Benthoscope was a deep sea submersible designed by Otis Barton after the Second World War. He hired the Watson-Stillman Company, who had earlier constructed his and William Beebe's bathysphere, to produce the new design of deep diving vessel, which was named from the Greek benthos, meaning "bottom".

The Benthoscope was essentially similar to the bathysphere, but was built to withstand higher pressures, with a crush depth of 10,000 feet (3,000 m). Its internal diameter was 4.5 feet (1.4 m), and its wall thickness was 1.75 inches (44 mm). It weighed 7 short tons (6,400 kg), an increase in weight of 1,600 pounds (730 kg) over the bathysphere. Two windows of fused quartz were installed, one facing straight ahead and the other diagonally down. Other arrangements followed the bathysphere, with oxygen supplied from cylinders, and calcium chloride and soda lime used to absorb moisture and CO₂ respectively.