Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sulfur in marine archaeological shipwrecks - the "hull story" gives a sour aftertaste

16.05.2008
Advanced chemical analyses reveal that, with the help of smart scavenging bacteria, sulfur and iron compounds accumulated in the timbers of the Swedish warship Vasa during her 333 years on the seabed of the Stockholm harbour.

Contact with oxygen, in conjunction with the high humidity of the museum environment, causes these contaminants to produce sulfuric acid, according to a new doctoral thesis in chemistry from Stockholm University.

The Vasa sank in Stockholm's harbour on her maiden voyage in 1628 and was salvaged in 1961. The impressively restored ship is, after conservation, on display in the Vasa Museum in Stockholm. At present over 2,000 acidic sulfate salt precipitates have been registered in the timbers of the wreck as a result of the sulfuric acid formation. In her doctoral thesis from Structural Chemistry at Stockholm University, Yvonne Fors indicates that sulfur contaminants are a common conservation concern for marine archaeological wood. Her thesis presents the background, consequences and some remedies for these processes.

The seawater at the Vasa's wreck site became heavily polluted over the course of time and bacterial degradation of organic waste from the growing city consumed most of the oxygen in the water. Malodorous hydrogen sulfide was produced by scavenging bacteria, resulting in the accumulation of different sulfur and iron compounds in the wreck's timbers during 333 years on the seabed.

... more about:
»Fors »Iron »Sulfur »Vasa »acid »sulfuric »thesis

"In the Vasa high sulfur concentrations are found only in the surface layers of the timbers, while for other shipwrecks such as the Mary Rose in Portsmouth, England, sulfur has penetrated throughout the hull. There are more than two tonnes of sulfur in each of them", says Yvonne Fors, who has studied how sulfur passes from seawater into the timbers. Advanced x-ray spectroscopic analyses at international research facilities in USA and France were used to map the distribution of the sulfur and iron compounds in the wood cells of the timber. Through contact with oxygen and high humidity conditions sulfur and iron compounds may develop sulfuric acid. Presently, there is approximately two tonnes of sulfuric acid in the Vasa's wood.

"It is essential to find out as much as possible about how and where the different compounds are bonded in the cell structure of the timber in order to be able to predict their reactivity and the possibility of removing them," says Yvonne Fors. It appears that the sulfur and iron contaminants can only be partially extracted, without seriously damaging the fragile wood. "It is important to keep a stable climate in the museum to slow down the processes," says Yvonne Fors. High acidity can have a long-term detrimental effect on the strength of the timber, and this must be limited. Yvonne Fors has carried out some promising initial experiments neutralising the acid in loose pieces from the Vasa by means of ammonia gas. However, any possible side effects on the wood must be carefully evaluated. The discoveries and conclusions in this thesis are an important first step in prolonging the expiration date of this national treasure.

The title of the thesis: Sulfur-Related Conservation Concerns for Marine Archaeological Wood. The Origin, Speciation and Distribution of Accumulated Sulfur with Some Remedies for the Vasa.
The thesis can be downloaded as a PDF file at:
http://www.diva-portal.org/su/theses/abstract.xsql?dbid=7627
Further information: Yvonne Fors, Department of Physical, Inorganic and Structural Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden; Phone: +46-8-162390, +46-70-4430007, e-mail: yvonne@struc.su.se

The Swedish warship Vasa sank on her maiden voyage in the mouth of the Stockholm harbour on the 10th of August 1628. The Vasa was fitted with what were then the most powerful armaments carried by any ship in northern Europe, and was sent to help the Swedish King Gustav II Adolf in the struggle for control over the Baltics. However, the ship lacked stability and keeled over in a gust and sank to a depth of thirty-two meters after sailing for just over a kilometre. The hull was salvaged in 1961, 333 years later, during a remarkable diving operation, and is now on display in the Vasa Museum in Stockholm.

Maria Erlandsson | idw
Further information:
http://www.vr.se
http://www.diva-portal.org/su/theses/abstract.xsql?dbid=7627

Further reports about: Fors Iron Sulfur Vasa acid sulfuric thesis

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>