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 Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State 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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>