Dana expeditions facts for kids
The Dana expeditions were a series of four important Danish science trips that happened between 1920 and 1930. These trips explored the oceans. The first two expeditions used a ship called Dana I. The third trip used a newer ship, Dana II.
These expeditions were partly paid for by the Carlsberg Foundation. They were all led by a famous biologist named Johannes Schmidt. The first three trips happened from 1920 to 1922. The last trip was from 1928 to 1930.
The main goal of these trips was to study how eels breed. During the first two expeditions, Schmidt proved his idea that European eels travel all the way to the Sargasso Sea to lay their eggs. The final expedition went to the Indian Ocean and collected many different samples.
Contents
Early Expeditions (1920–1922)
Planning the Ocean Journeys
From 1920 to 1922, the Dana ship went on three expeditions. These trips were led by a marine biologist named Johannes Schmidt. Schmidt and C. F. Dreschel first suggested a trip to explore the deep parts of the Atlantic Ocean in 1916.
At first, they thought about one very big expedition. But in 1917, Schmidt suggested two trips instead. The first would focus on the Atlantic. The second would sail around the world for two years. They decided to focus on the Atlantic first. They started planning and buying supplies. This was hard because World War I was happening. Schmidt also had bronchitis. By early 1918, they had most of what they needed.
Schmidt believed a trip around the world would be very helpful. It could get a lot of attention for Danish marine science. This would be like how the Challenger expedition helped the UK. But his ideas to change the plan were not successful.
In January 1919, they agreed that the first trip would start in Gibraltar in March. It would last three months. After World War I ended in November 1919, the first trip was almost ready. The Dana ship was finished by H.N. Andersen's East Asiatic Company. Andersen agreed to let Schmidt use the ship for three months and pay for it. But the start was delayed until 1920. This was so they could buy equipment at better prices. While they waited, the Dana carried goods for the company.
Schmidt and Dreschel then chose a special group to help with the expedition. Prince Valdemar of Denmark was the main leader. The group also included someone from the Carlsberg Foundation. The expedition was announced to the public in the summer of 1919. Schmidt then worked quickly. He wanted to prove his idea that European eels go to the Sargasso Sea to lay eggs. He wanted to do this before other scientists did. So, the big expedition was split into two smaller ones. The first one could be done fast.
In late 1920, Schmidt and Dreschel had a disagreement. Dreschel wanted to invite other countries to join the second trip. Schmidt wanted to keep it only for Denmark. He even said he would quit if it wasn't. Nothing came of these plans.
First and Second Trips
The first expedition started in early 1920 in England. The Dana left England on March 17 for Gibraltar. Schmidt joined the ship in Madeira. By April, they were in the Canary Islands. They left there on April 11. Seven days later, they reached the Sargasso Sea.
Soon after, the crew started catching many European eel larvae. They were looking for where the eels breed. But the ship started to leak. It had to go to Charlotte Amalie, St. Thomas, for repairs. Because of this problem, the East Asiatic Company gave Schmidt another three months with the ship. They waited on St. Thomas for a month. Then they went back to the Sargasso Sea in June.
However, by then, the season for eel eggs to hatch was over. They still caught 6,069 larvae of European eels. They also caught 1,027 American eel larvae. The first expedition ended on July 4 in the Bermuda Islands. The Dana was returned to the East Asiatic Company in Charleston, South Carolina. The group went back to Denmark. They still had most of their money. But they did not have clear proof that European eels spawned in the Sargasso Sea. A second expedition left on August 30, 1921, with the same goal.
Third Expedition with Dana II
Schmidt's third expedition made him known as a top marine scientist. In late 1920, the Danish government bought a new research ship in Great Britain. It was brought to Denmark, fixed up, and renamed R/V Dana or Dana II. This new ship had 10 kilometers (about 6 miles) of metal wire. This let it "fish deeper than anyone before."
The expedition began in late 1921. It arrived near Portugal and Spain in September. There, they studied the Strait of Gibraltar. The expedition worked for ten months. In early December, the Carlsberg Foundation agreed to pay for the trip to go through the Panama Canal. It did so on January 10.
In the Pacific Ocean, Dana II took many samples. These showed that the Pacific Ocean was cooler and less salty than the Atlantic. They also found an oxygen minimum zone. This is a layer about 500 meters (1,640 feet) below the surface where there is very little oxygen. The researchers on Dana II were the first to find this. Many tiny sea creatures (plankton) helped them see upwelling. This is when deep, cold water rises to the surface. Samples from deep levels showed more different kinds of species than in the Atlantic. On January 20, they left the Pacific. After stopping in Lake Gatun—where they found many desmid algae—they returned to Europe from Bermuda on May 30.
What Happened Next
From 1922 to 1923, Schmidt shared his ideas about how eels breed. His expedition became famous in magazines, on pottery, and through awards. The expedition found many new species. They also caught valuable live animals. And they made several important discoveries. A film showing the expedition was made in October 1922.
Fourth Expedition (1928–1930)
Schmidt started his fourth Dana expedition in June 1928. He returned in June 1930. Its full name was "The Carlsberg Foundation's Oceanographical Expedition round the World 1928-30 under the Leadership of Professor Johannes Schmidt." This was Schmidt's biggest expedition.
The ship traveled over 65,000 nautical miles (about 120,000 kilometers) from Europe to the Indo-Pacific region. One goal was to study the oxygen minimum zone found in 1920. Another goal was to look for freshwater eels in the Indian Ocean. They found larvae of a "true" freshwater eel in the Pacific. They also collected many other samples. Schmidt also used this trip to check his earlier research.
The science journal Nature wrote about Schmidt's work. It said that from North Iceland to Brazil, and from the Baltic Sea to Panama, Schmidt and his team studied the ocean. They looked at the water's physical, chemical, and biological conditions from the surface to the bottom.
The expedition also found a giant larva. They thought it belonged to the eel family. Based on how fast common eels grow, they guessed this larva could grow to be 30 meters (about 98 feet) long. Eleven years later, Anton Frederik Bruun, who helped lead the expedition, said, "I believe in the sea serpent." He gave talks about its possible existence.
