Valdivia expedition
The Valdivia expedition was the first large-scale German expedition to explore the deep sea . Its initiator and scientific director was the zoologist Carl Chun . The research ship Valdivia , a steamer of the Hamburg-American Packetfahrt-Actien-Gesellschaft ( HAPAG ) that had been converted for the expedition , set sail on July 31, 1898 and returned on May 1, 1899 from its voyage that took him over 32,000 nautical miles through the Atlantic and led the Indian Ocean back to Hamburg. In addition to extensive depth sounding under the direction of the oceanographer Gerhard Schott , the main objective of the company was to collect biological samples. The yield was so overwhelming that the publication of the scientific report in 24 volumes was not completed until 1940.
precursor
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Around the middle of the 19th century it was still believed that no life would be possible below a water depth of about 550 meters (Abyssus theory by Edward Forbes ). In 1850, however , the zoologist Michael Sars proved that in Norwegian fjords and off the Lofoten there is a rich fauna below this mark. Inspired by these observations, Wyville Thomson undertook dredges in the waters around Great Britain and the Mediterranean in the late 1860s . In the years 1872 to 1876, the first oceanographic expedition took place under Thomson's direction on the corvette HMS Challenger , which covered a distance of 68,890 nautical miles and circled the earth in the process. The results of the Challenger expedition were so extensive that their publication in fifty volumes lasted until 1896 and occupied numerous international scientists. Thousands of species of previously unknown marine organisms have been described. Under the impression of the Challenger expedition, several states, but also private individuals, started their own undertakings to study the deep sea in the following years. Mention should be made of the expeditions of the American Alexander Agassiz with the ship Blake in the Gulf of Mexico, the Caribbean Sea and along the Atlantic coast of the USA (1877-1880) as well as with the steamer Albatross along the west coast of Central America to the Galapagos Islands (1891). At the end of the 1870s, the Norwegians Henrik Mohn and Georg Ossian Sars explored the oceanographic conditions of the North Atlantic with the Vøringen . In the 1880s there were four French expeditions under Alphonse Milne-Edwards in the Atlantic and the Mediterranean. The Mediterranean was also the destination of the Prince of Monaco and the Austro-Hungarian Pola expeditions , the last two of which also led to the Red Sea .
preparation
Germany had not undertaken its own deep-sea expedition until the 1890s. On the SMS Gazelle's research trip from 1874 to 1876, extensive soundings were carried out to measure profiles of the sea floor, but the gazelle was not equipped to take samples of the deep-sea fauna. On the plankton expedition of 1889, only six depth soundings were carried out. The collection of organisms focused on the plankton of the uppermost water layer to a depth of 200 meters.
Carl Chun, who had plans for a deep-sea expedition, presented his plan to the assembly of the Society of German Natural Scientists and Doctors in September 1897 , encouraged by the influential Prussian Ministerial Director Friedrich Althoff . In his zoological and oceanographic investigations, Chun wanted to concentrate primarily on the Indian Ocean , which the Challenger expedition had only touched on its southern edge. At the suggestion of a commission set up by the Society's scientific committee, consisting of the polar researcher Georg von Neumayer , the physician Rudolf Virchow and the anatomist Heinrich Wilhelm Waldeyer , the assembly approved an immediate application to Kaiser Wilhelm II. This application was accepted with goodwill, and on 31 January 1898, the German Reichstag approved the requested funds of 300,000 marks for the planned expedition.
Attendees
The official scientific staff consisted of the zoologist and expedition leader Carl Chun (Leipzig), the botanist Wilhelm Schimper (Basel), the oceanographer Gerhard Schott (Hamburg), the chemist Paul Schmidt (Leipzig), the zoologists Carl Apstein (Kiel), Fritz Braem (Breslau) and Ernst Vanhöffen (Kiel) as well as the navigation officer of HAPAG Walter Sachse (Hamburg).
In addition, the doctor and bacteriologist Martin Bachmann (Breslau), the zoologists August Brauer (Marburg) and Otto zur Strassen (Leipzig) and the scientific draftsman and photographer Friedrich Wilhelm Winter (Frankfurt am Main) joined the expedition. R. Schmitt (Leipzig) was on board as a conservator. After Bachmann's death, on February 16, 1899, the doctor G. Hay joined the expedition. The crew of the Valdivia , including Captain Adalbert Krech, consisted of 43 people.
Technical Equipment
The ship
After lengthy preliminary negotiations and thorough appraisals, the Reichsmarineverwaltung decided to charter the Valdivia steamer on the Hamburg-America Line for the expedition. But first some modifications had to be made. On the aft deck, a fifteen square meter deckhouse was converted into a microscope room. A chemical and a bacteriological laboratory as well as a photographic darkroom have been set up in the intermediate deck of the aft ship. In the intermediate deck of the fore ship there was the preservation room, in which the tools, reserve cables and nets were kept, but which was increasingly filled with vessels containing preserved organisms. To improve the lighting conditions in the laboratories, additional windows were cut and the electrical lighting was expanded. In addition, some cold rooms were created. Each scientist could have their own cabin as living space. A large steam winch was set up on deck and a heavy steel loading boom with a lifting capacity of ten tons was attached to the foremast , both in order to be able to lift the heavy dredges (bottom trawls) from the bottom of the deep sea on board.
Scientific equipment
Biological equipment
The most important part of the biological equipment were the various nets, above all the bottom trawls (also called dredges or trawls ), several of which were on board in various designs and sizes. Deep-sea traps equipped with baits were also used to catch animals at the bottom of the deep sea. In addition, plankton nets made of fine silk gauze were carried along, which were lowered to a certain depth and then pulled vertically upwards with the ship at a standstill in order to filter even the smallest planktonic organisms from the water. As a further net variant, locking nets were used, with which it was only possible to selectively catch organisms that occur at a desired depth.
To tow the dredges, a cable drum was installed on the fore ship , containing a 10,000 m long steel cable spliced together from two 6000 and 4000 m long pieces, the longer of which was 10 mm in diameter and the shorter 12 mm. For the lighter plankton nets, there was also a second, smaller cable drum on the fore ship, which took a weaker steel cable 7,000 m in length.
To cool the catch there was an ice machine on board that produced five kg of ice a day. The expedition was equipped with a large number of glass containers and with 8000 liters of 96% alcohol and 500 liters of formalin for preservation purposes.
Oceanographic equipment
The most important devices on board were two deep-sea plumbing machines, one of the French design after Jules Le Blanc (1832-1910), the other made according to the American system by Charles Dwight Sigsbee . The latter was equipped with piano wire 0.9 mm in diameter and was preferred by the expedition because it showed the ground contact more clearly.
Since great importance was attached to temperature measurement, the expedition was equipped with several deep-sea thermometers of various types. This included an electrical thermometer developed by Siemens that could be used for depths of up to 750 meters. The physical examination of the sea water, which was taken from different depths with special water scoops, was carried out with hydrometers and refractometers . A standardized color scale was used to assess the water color .
For meteorological studies there was on the Valdivia more enrollees partly barometer, thermometer and hygrometer, plus a Aßmann MOORISH Aspiration and Schwarzkugelinsolationsthermometer for measuring the intensity of solar radiation.
Course of the expedition
Atlantic Ocean
On July 31, 1898, the Valdivia was ceremoniously adopted in Hamburg. John Murray , editor of the Challenger Expedition's research reports , was also on board as a guest of honor . In the North Sea , the first dredging operations were carried out on the Dogger Bank, mainly to test the technology and gain experience with it. On August 3rd, Edinburgh was called, where Murray disembarked and the expedition received further equipment. A small damage to the cable drum could be repaired quickly. On the evening of August 4th, the ship left for the Faroe Islands . On August 6th and 7th the first deep sea scouts and dredges of the Valdivia expedition were undertaken here. In addition, the water temperature was measured at different sea depths. North of the island of Suðuroy , near the 62nd parallel, the expedition reached its northernmost point on August 7th and then set course for the Canary Islands . After a heavy storm from August 9th to 13th, the scientific work could only be resumed on August 15th. East of Madeira , the Seine bank was visited and measured on August 18th. Tenerife was called on August 20th . After botanical excursions on Tenerife and Gran Canaria , the course was set for the African coast. On August 24, the ship was 40 nautical miles from Cape Bojador . Following the north equatorial current, the Valdivia reached the Cape Verde Islands on August 29th . After several dredges in the vicinity of Boa Vista , which above all provided numerous glass sponges , the route was continued in a south-easterly direction and the warm Guinea Current was crossed from August 31st .
On September 6th there was the equator baptism . The expedition members carried out extensive work in the Gulf of Guinea . The trawls were pulled over the ground at a depth of almost 5000 meters. The greatest sounded depth was 5695 meters. On September 15, the ship entered the port of Victoria in Cameroon, then a German colony . This was followed by a three-day excursion via Buea on the flank of the Cameroon Mountain . On September 19, they left Victoria, bypassed Cape Nightingale and entered the capital, Cameroon City . The expedition leader visited Rudolf Manga Bell , the King of the Duala , who was also received on board the Valdivia . Then eleven of the scientists took a steamboat trip on the Wouri inland to the rapids of Jabassi, and nine of them became infected with malaria . On September 25, the ship continued its voyage, followed the West African coast and entered the port of Banana at the mouth of the Congo on October 1 . At the invitation of the Belgian colonial administration, the river was sailed with a barge to the then capital Boma and the surrounding savannah was explored. On October 5th, the Valdivia lifted anchor and headed for the large fish bay ( Baía dos Tigres ), rich in plankton and fish, on the Angolan coast . From October 10th to 12th, the fish stocks, but also the rich bird life, were studied here.
The Valdivia now steered away from land into the South Atlantic. Tormented by malaria attacks and choppy seas with strong southeast trade winds , work could only be resumed on October 15. The soundings on October 17th surprisingly revealed a depth of less than 1000 m, where one had actually expected around 5000 m. As it turned out later, the expedition had discovered the whale ridge , which connects the mid-Atlantic ridge with southern Africa at the height of the Walvis Bay . The existence of such a barrier was also deduced by the Austrian oceanographer Alexander Supan from the measured temperature profiles in the Angola and Cape Basins , which show an average difference of almost 2 degrees at a depth of 4000 meters. The shallowest part of the whale ridge is now called Valdivia Bank . The dredge train on the bank brought in a rich catch. Dozens of deep sea fish ( Macrurocyttidae ), more than a hundred large red deep sea crabs ( Geryon maritae ) as well as hermit crabs , corals , sea cucumbers and barnacles went into the net. On October 26th we reached Cape Town , where Schimper undertook a botanical excursion inland, while the Valdivia immediately set out again to explore the continental shelf south of Cape Agulhas . From October 29th to 31st, the ship was in Port Elizabeth and then returned to Cape Town. On the Agulhasbank 29 dredges were undertaken, which, in addition to typical species from the Atlantic and Indian Oceans, also brought to the surface those that the zoologists working with Carl Chun had expected in Antarctic waters.
The Valdivia was anchored in Cape Town from November 6th to 13th . Then she drove south-south-west into areas that had not yet been explored and explored oceanographically, because both the Challenger and the Gazelle had left Cape Town to the south-east in the direction of Kerguelen . It was hoped to rediscover Bouvet Island , which was discovered by Jean-Baptiste Charles Bouvet de Lozier in 1739 , but was last sighted in 1825. In the 1840s, James Clark Ross and Thomas Moore (1819–1872) had searched in vain for the island. Carl Chun wanted to research the basic Antarctic fauna in their vicinity. On November 24th, the sounding of the depth indicated that a ridge had been reached again. The sea area was systematically searched and on November 25th the island actually came into view. Their position was determined exactly and an initial mapping was carried out. Five dredges were carried out near the island. The northernmost point of Bouvet Island was named Cape Valdivia . The glaciated plateau in the center of the island was named after Kaiser Wilhelm II.
Indian Ocean
On November 28, 1898, the Valdivia left the waters around Bouvet Island and, until December 16, always drove along the edge of the pack ice along 50 degrees of longitude to the east. A large number of icebergs were photographed and measured during the trip . Thanks to the good weather, depth soundings could be carried out every day. Up until the start of the expedition, there had only been 15 soundings south of the 50th parallel worldwide. The Valdivia increased this number by 29. For theoretical considerations, the Antarctic Sea had previously been ascribed only a shallow depth. However, a large part of the soundings of the Valdivia resulted in depths between 5000 and 6000 m. On December 13th, when the ice border receded, the opportunity arose to advance further south towards the Antarctic mainland. Although the Valdivia was not ice-capable, the captain managed to steer south and reach the 64th parallel by December 16. When the southernmost point of the route was reached, Enderbyland was only 100 nautical miles away. On December 17, a dredging was carried out at a depth of 4636 m, which was a high risk due to the duration of several hours and the constant danger of being trapped by the ice. Here, too, the yield of animals was overwhelming. The stones brought up by the trawl made it clear that Enderbyland is not of volcanic origin, as previously assumed.
Due to stormy weather, which prevented any scientific work, the Valdivia now drove to the northeast and reached the Kerguelen on Christmas Day , where she anchored in the well-protected Gazelle Bay for three days to carry out the necessary cleaning of her steam boiler. The time was used to study the unique flora and fauna of the archipelago. The journey continued on December 28th. Since the weather had calmed down, samples of the marine life could be collected again. After a stopover in the Christmas port, where leopard seals and penguins were also killed and taken on board as samples, the Valdivia left Kerguelen on December 29th.
The turn of the year was celebrated with a strong westerly storm between the Kerguelen and St. Paul Island , a small volcanic island that had been scientifically explored in detail by the Novara expedition in 1857. The Valdivia expedition arrived at the island on January 3, 1899. During a dredge at a depth of almost 700 m, the trawl was severely damaged by the rocky seabed. The catch was of scientific importance insofar as the corals brought up in large numbers proved to be valuable for the elucidation of the connection between the deep-sea fauna of the Atlantic and Indian Oceans. The next day we reached the nearby Amsterdam island . The bottom trawl brought basaltic bombs and only a few animals to light near the island and on the following day at a distance of over 100 nautical miles .
The Valdivia continued on its way north-east only interrupted by regular soundings and dredges . On the morning of January 14th, the expedition doctor and bacteriologist Martin Bachmann was found dead in his cabin. The following day he was buried in the sea. On January 17th, the expedition passed the Cocos Islands without going ashore. The following day a dredging was carried out at a depth of over 5000 m. The deep sea thermometer was unable to withstand the pressure of over 500 atm and broke, but various animals were found even at this depth. With the vertical net, rich prey was made from a depth of up to 2500 m, including deep-sea fish.
On January 21st, Sumatra came into view. On January 22nd, the Valdivia entered the Emma port of Padang . After visiting the highlands, the expedition continued on January 30th towards Siberut , the largest of the Mentawai Islands off Sumatra . The aim was to examine the little-explored Mentawai Basin more closely from a zoological and oceanographic point of view. The soundings revealed depths of up to 1760 m. The special feature of the measured temperature profile was that the temperature fell steadily down to a depth of 900 m and then remained constant at 5.9 ° C down to the bottom. It was concluded from this that there is no water exchange with the free ocean beyond this mark, i.e. that the roads between the Mentawai Islands, which connect the basin with the ocean, cannot be deeper than 900 m. The open ocean was reached again through the Siberut Strait. On February 1st, the equator was crossed and the next day the island of Nias was visited, which was briefly visited. 60 nautical miles west of Nias were sounded 5214 m on February 3rd. With further frequent sounding, Aceh was stopped and the island of Weh entered briefly. The journey continued to the Nicobar Islands . Dredsch trains on February 7th and 8th uncovered mainly glass sponges . On February 9, the Valdivia anchored in the port of the island of Nankauri . The scientists insisted on going ashore here and visiting a village.
The journey continued through the Bay of Bengal towards Ceylon without dredging trains . On February 13, 1899, the Valdivia dropped anchor in the port of Colombo . With the help of the German consulate it was possible to win G. Hay as a new doctor for the expedition. Diego Garcia entered via the Maldives on February 23 . Regular depth soundings have shown that the Maldives are sitting on an oceanic ridge sloping from north to south, which continues to the Chagos Archipelago . After a short stay and a visit from Diego Garcia, we took a west course and reached the Seychelles island of Mahé on March 5th . Under the leadership of August Brauer, who had spent several months on the island in 1894/95, the remains of the jungle around Mount Harrison were visited. On March 8th, the ferry crossed over to Praslin , the second largest island in the Seychelles, and in the evening set course west towards German East Africa .
On the seven busy days before reaching the East African coast, the vertical nets brought rich yields of fish and cephalopods from the open water to the daylight, including a living hunchbacked frogfish , a bizarre fish larva with long stalks and cephalopods with stalked eyes. On March 15, the Valdivia entered the port of Dar es Salaam . After thorough exploration of the area and a dredging move in the coastal waters, the ship called at Zanzibar on March 21 .
In the last section of the expedition, the Valdivia followed the African coast at a distance of 15 to 20 nautical miles to the northeast. By the time they reached Aden on April 5, the researchers used the entire arsenal of their research methods. Another 25 trains were carried out with the large trawl. In Aden the scientific program of the expedition was fulfilled. The botanist Wilhelm Schimper disembarked to take a closer look at the flora of the area, which has a number of endemic species. The Valdivia made its way home through the Red Sea and the Suez Canal . On April 14th, coal was stashed again in Port Said . After the Strait of Messina (April 18), the Strait of Gibraltar was passed on April 22nd . On May 1, 1899, the ship entered the port of Hamburg, where the returnees were enthusiastically received.
Results
Biological results
The Valdivia expedition was committed to the biological research concept of the 19th century, describing all animal species and classifying them in the scientific system . Indeed, it was possible to find a large number of new animal forms, examine them while on board the ship and finally preserve them. The knowledge of the deep-sea fauna was thus significantly expanded.
A particular focus of the expedition was the study of the adaptation of organisms to the extreme conditions of their environment. Many deep-sea organisms have luminous organs that have been the subject of detailed anatomical studies. While the eyes of many bottom dwellers have receded, free-swimming fish, but also octopuses, have often developed telescopic eyes. Brauer and Chun have described this in detail.
One question which Carl Chun was particularly important to clarify was that of pelagic plankton. He believed that the entire water column and not just the deep sea floor was populated by organisms. This was contradicted by Alexander Agassiz, who - like the majority of marine biologists at the end of the 19th century - held the opinion that the free water of the deep sea was azoic. With ingenious locking nets that only fished off the desired part of the water column, Chun was able to prove a rich pelagic fauna in all parts of the ocean to which the expedition traveled. He also described the relationships of surface plankton to deep plankton and pointed to seasonal vertical migrations.
Oceanographic and geographic results
The oceanographic work was given a lower priority than the marine biological work. Soundings were often carried out to prepare for fishing trips with the vertical or bottom trawl. On the other hand, the course of the Valdivia was chosen as far as possible so that it touched areas that had not yet been explored or only little explored, especially in the Antarctic waters and the Indian Ocean. A total of 186 depth soundings were carried out during the Valdivia expedition. Mud samples could also be taken from the seabed 132 times. In the remaining cases the bottom was either rocky or the plumb bob was lost. Profiles of temperature and salinity were also usually recorded.
The first oceanographic discovery was the rather accidental finding of the Valdivia Bank off Walvis Bay. It later turned out to be part of the whale ridge, which is now known to run from the African continent to the Mid-Atlantic Ridge. For the expedition participants the shallow depth of less than 1000 meters at this point was a surprise.
The most important part of the expedition from an oceanographic and geographical point of view was the section between Cape Town and the Kerguelen Archipelago. The direct route, which had already been explored by the Challenger and the Gazelle , was deliberately avoided. Instead, the Valdivia drove south-south-west towards Bouvet Island, which had not been found for 73 years despite multiple attempts. The rediscovery of the island, which had already been assumed to have sunk in the sea, was a popular success for Captain Krech. For the area that the Valdivia then traveled from west to east, i.e. south of 50 ° south latitude and from 0 to 60 ° east longitude, no depth measurements were available in 1898. The crew as well as the ship's command were challenged to measure depths of often more than 5000 m with the not easy to use plumbing machines under the most difficult weather conditions and before the invention of the echo sounder . However, it was possible to carry out a deep sounding almost every day. The results were surprising. According to the soundings of the Challenger in the eastern half of the southern Indian Ocean, a gradual decrease in sea depth towards the South Pole was assumed. However, the Valdivia expedition almost always found depths of more than 4000 m around the 60th parallel, once even 5733 m. Gerhard Schott named this part of the deep sea Indian-Antarctic Basin . Today the term West Indian South Polar Basin is more common. The expedition was also able to provide new information on the expansion of the Antarctic continent. Rock samples found while dredging off Enderbyland were not of volcanic origin. This proved that this is not a volcanic island, but part of the Antarctic mainland.
Publication of the results
Multi-page, very detailed newspaper reports - including research results - appeared in the German Reichsanzeiger during the expedition . Immediately after the end of the trip, individual results were published in specialist journals. A popular scientific travelogue appeared in 1900 under the title From the depths of the ocean . A second, greatly expanded edition appeared as early as 1903. In it, Chun not only presents the zoological and oceanographic work and findings, but also describes in detail the flora that the expedition members found when they went ashore. This is supplemented by ethnological considerations and brief outlines of the history of the discovery of the islands and regions visited. The 24-volume complete edition of the arrangements of the collected material was published between 1902 and 1940 as Scientific Results of the German Deep Sea Expedition on the steamer “Valdivia” 1898–1899 .
The editor was Carl Chun until his death in 1914, then August Brauer, Ernst Vanhoeffen and finally Carl Apstein. In addition to the participants in the expedition, Heinrich Schenck , Franz Doflein , Heinrich Balss , Johannes Thiele , Karl August Möbius , Günther Enderlein , Franz Eilhard Schulze , Ludwig Döderlein , Eduard von Martens , Emil Philippi , Anton Reichenow , Johannes Meisenheimer , Ferdinand Zirkel , Robert Lendlmayer von Lendenfeld , Richard Goldschmidt , Willy Kükenthal , Wilhelm Weltner and Valentin Haecker appear as authors.
literature
- Carl Chun: From the depths of the ocean . 2nd revised and greatly increased edition. Gustav Fischer, Jena 1903 (Online: edoc server of the Humboldt University of Berlin ).
- Gerhard Schott: Oceanography and Maritime Meteorology . (= Carl Chun (Hrsg.): Scientific results of the German deep-sea expedition on the steamer “Valdivia” 1898–1899 , Volume 1), Gustav Fischer, Jena 1902.
- August Brauer: The deep sea fish. Systematic part . (= Carl Chun (Hrsg.): Scientific results of the German deep-sea expedition on the steamer "Valdivia" 1898–1899 , vol. 15, part 1), Fischer, Jena 1906.
- August Brauer: The deep sea fish. Anatomical part . (= Carl Chun (Hrsg.): Scientific results of the German deep-sea expedition on the steamer “Valdivia” 1898–1899 , Vol. 15, Part 2), Fischer, Jena 1908.
- Rudi Palla : Valdivia. The story of the first German deep sea expedition . Non-fiction book, Galiani Verlag (Berlin 2016). ISBN 9783869711249
Individual evidence
- ↑ Ludwig Darmstaedter (ed.): Handbook for the history of natural sciences and technology , Springer, Berlin 1908, p. 521
- ↑ Deutscher Reichsanzeiger No. 210 of September 5, 1898, No. 280 of November 26, 1898, No. 309 of December 31, 1898, No. 73 of March 25, 1899, No. 99 of April 27, 1899.
- ^ Carl Chun: Scientific results of the German deep-sea expedition on the steamer "Valdivia" 1898-1899 . G. Fischer, Jena, 24 volumes, 1902–1940, doi: 10.5962 / bhl.title.2171 .
Web links
- Information on the deep-sea expedition on the homepage of the Museum für Naturkunde, Berlin ( Memento from January 31, 2008 in the Internet Archive )