Typical plankton analysis data sheet from the Discovery II, 13 April 1932.
Rediscovering the Discovery
25 February 2011
Between 1925 and 1951, three research ships made a series of pioneering voyages in Southern Ocean. The Discovery Investigations are well documented, but the valuable raw data they brought back remained out of reach of modern science. Andrew Mackey explains how these important records are finally seeing the light of day.
As I look through a large box containing all sorts of paraphernalia, I pick up a hand-drawn illustration of icebergs floating along the coast of a mountainous land. Under this is a notebook that belonged to one of the crew of the RRS William Scoresby. It opens on a page dated 3 November 1927, which describes the awful smell as the ship approaches a whaling station on the island of South Georgia. This is fairly typical of the hundreds of boxes around me, here at the National Oceanography Centre (NOC) archives in Southampton. They contain the records from the Discovery Investigations.
The Royal Society commissioned the Discovery Investigations, one of the most ambitious scientific studies ever undertaken. It was led by the RRS Discovery - the vessel that carried Scott and Shackleton on their first successful journey to the Antarctic. Among the esteemed crew of 47 was the director of the Investigations, Dr Stanley Kemp - according to the journal Nature, 'probably the leading authority on oceanography'. He was joined by Sir Alistair Hardy, founder of the Sir Alistair Hardy Foundation for Ocean Science (SAHFOS) and inventor of the Continuous Plankton Recorder (CPR), a device - used today more than ever - that is towed through the ocean collecting and preserving plankton on an ever-moving band of silk: ingenious! The following year Discovery was accompanied by the RRS William Scoresby, a trawler much better suited to maintaining the consistent speed needed for ocean sampling. Discovery was powered by coal-fired steam but relied on sail for long journeys. As a result she was replaced from 1929 by her namesake Discovery II, the largest research ship ever to explore the Southern Ocean.
The RRS Discovery.
The aim of the expeditions was to investigate all aspects of the ocean affecting the distribution of whales. Antarctic whale numbers were in steady decline, but no one knew enough about their distribution and migrations, or about the food chain supporting them, to do anything about it. Gaining this knowledge meant studying the biology, chemistry and physical oceanography of some the harshest seas on the planet. The data gathered resulted in 34 volumes of Discovery Reports, which contributed enormously to our understanding of this remote region. They were the first to describe the importance of krill - shrimp-like, planktonic crustaceans that form a critical link in the food chain - and the existence of the Antarctic Convergence. This is an oceanographic phenomenon that marks the physical boundary of the Southern Ocean, an area rich in marine life where cold, northward-flowing polar water meets warmer sub-Antarctic waters.
Baleen whales live almost exclusively on zooplankton, so the research into these tiny marine animals in particular was of paramount importance. In total nearly 4000 observation points or 'stations' from around the Southern Ocean were sampled for the composition and abundance of their plankton, along with hydrological readings such as water temperature and salinity. Most of these observations were made from the surface down to more than a thousand metres in depth.
Historical data can contribute a great deal to research into the effects of environmental change. Plankton are excellent 'biological indicators' - they are highly susceptible to changes in their environment and their response, in turn, can tell us about those changes. By understanding past ecological changes in the plankton community, scientists will be better equipped to predict future changes. That's why this raw data is so valuable - it gives us a window on the last 80 years.
Historical datasets can provide important context to new observations, and help scientists analyse longer-term trends and changes.
But scientists need access to complete, original ecological datasets to make meaningful comparisons with the past, and much of the documentation that was used in the synthesis of the now famous Discovery Reports has become separated and jumbled over the decades, so this information just hasn't been available to the scientific community. Until now.
This is where I come in. I work for the British Antarctic Survey (BAS) and, together with NOC and the Natural History Museum, London (NHM), I am working on a project to restore the true value of these incredible voyages, by bringing all the documents and data from the investigations together for the first time.
The idea is to make all the data available through an open-access, online data portal, giving everyone from the public to marine scientists the world over direct access. There will also be links to maps, graphs and the original Discovery Reports. NHM also has more than 27,000 jars containing the actual plankton samples. By carefully piecing together the various bits of information we can link a sample record with its corresponding jar. We're also identifying those yet to be analysed - several thousand jars may never even have been opened since they were collected, offering the exciting prospect of first-hand analysis of an 80-year-old ecosystem.
Some of the RRS William Scoresby crew.
A crucial part of the process is the painstaking entry of the original data onto spreadsheets. Tedious though this sounds, it's probably the most important stage in the data recovery. Without meticulous attention to detail, an error could lead to seriously wrong conclusions being drawn further down the track.
Research often focuses on gathering new data through expensive fieldwork and experimentation, but doesn't fully explore the potential of the large quantities of existing historical data. This means that important information is often neglected. Historical datasets can provide important context to new observations, and help scientists analyse longer-term trends and changes. Global climate change and ocean acidification would have meant little to the scientists and crew of the Discovery Investigations, but the data they collected may help us understand these phenomena. Changes in the abundance and distribution of plankton could have profound effects higher up the food chain, with potentially catastrophic consequences.
Since these historic voyages, many regions of the Southern Ocean have become warmer, particularly in the south-west Atlantic sector, and the old data will help us better understand whether the distribution of zooplankton communities has changed across the Southern Ocean as a result. So as well as making the records accessible to other researchers, we'll be publishing the results of our own modern analysis of the data. This will establish a baseline against which to compare present and future findings that will effectively extend our knowledge back in time, and give important context to the environmental changes we're seeing today.
The final Discovery voyage was made in 1950-51, 26 years after the first. The knowledge gathered by the investigations was not enough to prevent the massive exploitation of whales that has taken place during the last century. But the mindset of those involved, to investigate everything and overlook nothing, did bring about a comprehensive understanding of this harsh and most demanding of oceans.
Searching through the collections is an exciting part of my work; I never know what I might find once I open the lid of another old box. Sometimes I'll find beautiful, handwritten letters, black-and-white photographs of amazing scenery, and newspaper cuttings from the 1920s. But what I'm really looking for is the priceless plankton-catch data. These raw data sheets are the real treasure.
Andrew Mackey is a marine biologist in the ecosystems department and the Polar Data Centre at the British Antarctic Survey, in Cambridge. Email: Anck4@bas.ac.uk
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