Friday Find: Adrift for the sake of science

Drift bottles were once important scientific tools

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Drift bottles have become poetic symbols of loneliness: A desperate person writes an open letter to the world, closes it up into a bottle, and tosses it into the sea in the hopes of making a connection or being found and rescued from their shipwreck on a distant island. 

But before the 1970s, many important scientific studies were conducted via bottle. 

 
This is a clear bottle with a US Coast and Geodetic Survey flag. There is a pink drift card inside.

Bottles like this one were used by scientists up until the middle of the twentieth century for studying ocean currents. This one was left unused during a 1959 study conducted by the Coast and Geodetic Survey, a bureau which was later incorporated into NOAA.

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Scientists would carefully seal messages into glass containers and throw them from ships or planes in specific locations. Sometimes, 4H clubs would even assist with the work. 

Citizens who found bottles with cards were often paid small amounts of money for their return. A Bureau of Commercial Fisheries study conducted between 1962-1963 included more than 7,000 bottles filled with postcards in both English and Spanish, each offering a reward of 50 cents if the card was mailed back to the laboratory doing the study. Respondents were asked to record the exact location and time that they found the bottle. 

Left: A notice from the Coast & Geodetic Survey explaining the large-scale study of ocean currents. It was stuffed inside a drift bottle. Right: A postcard that the finder of a drift bottle could return to the U.S. Coast & Geodetic Survey with information on where and when the bottle was found. This was also stuffed inside a drift bottle.
Left: A notice from the Coast & Geodetic Survey explaining the large-scale study of ocean currents. It was stuffed inside a drift bottle. Right: A postcard that the finder of a drift bottle could return to the U.S. Coast & Geodetic Survey with information on where and when the bottle was found. This was also stuffed inside a drift bottle. (Image credit: U.S. Coast & Geodetic Survey)

Researchers then made maps detailing where and when each bottle was found. The data provided insights into how currents moved through remote parts of the ocean. For the Fisheries study, researchers used the results to figure out how changes in currents affected shrimp crops. 

Other drift bottle studies were conducted by the U.S. Coast and Geodetic Survey. Often, the most important variable for such studies was speed. Bottles that moved quickly meant a strong current was present. Some scientific papers note that the bottles that were found on shore many months or years later were not useful, despite public fascination. Several very old drift bottles have been found along the shorelines of Massachusetts and Alaska in recent years, which has renewed public interest in this archaic method of scientific study. 

Drift bottles were eventually replaced by drift cards made of wood, aerial photography and the development of satellite networks. Today NOAA is able to provide incredibly detailed views of a changing ocean in real time thanks to drifters, satellites, GPS-enabled sensors and powerful computers. 

An increased awareness regarding marine debris and its impact on ecosystems prompts us to ask that no one throw anything – including bottles with notes – into the water anymore.

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