Sunday, 6 August 2017

Bill Sladen (1920-2017): Penguins and Salt Glands

A number obituaries of William Joseph Lambart Sladen who died on 29 May aged 96 have been published in recent weeks. While they all record his pioneering studies on penguins in the Antarctic, his later involvement with migration and conservation projects in the northern hemisphere and his detection of DDT in penguins in the 1960s, they do not mention his involvement with a major scientific discovery of the 1950s which explained how penguins and other birds survive at sea.

Obituary in The Times

This year, marks the 60th anniversary of the announcement of the discovery of salt glands by Knut Schmidt-Nielsen and the publication of an abstract describing the work in Federation Proceedings. A full paper appeared in the American Journal of Physiology in March 1958. A month later a paper in Nature appeared entitled, Nasal salt secretion in the Humboldt Penguin by Schmidt-Nielsen and Sladen, which suggests that the work was done only a short time after that reported in the first paper on the Double-crested Cormorant Phalacrocorax auritus.

Schmidt-Nielsen and Sladen wrote:

In order to establish whether extra-renal salt excretion is of importance in the salt balance of other marine birds, we took advantage of the colony of Humboldt’s penguins (Spheniscus humboldti) in the laboratory of one of us (W.S.). These birds had been caught in the wild six months before, they were doing well in captivity, and were considered to be free of disease. Trial experiments in April 1957 showed that nasal secretion did occur, so the following experiments were performed.

The rest, as they say, is history.

How Schmidt-Nielsen and Sladen got together to do the study I do not know. Since the penguins were kept in Sladen’s lab at Johns Hopkins, I assume the male penguin used was given its salt-loaded fish in Baltimore.

I found this photograph of an Emperor Penguin skull which shows the
supra-orbital position of the nasal salt glands

Sladen by this time had already made his name from studying penguins in the Antarctic. British-born, medically-qualified and working as medical officer as well as biologist for the Falkland Islands Dependency Survey—FIDS—now the British Antarctic Survey, he was sole witness to the horrendous hut fire at Hope Bay in November 1948 that resulted in the death of two members of the survey team. After the fire he spent the next sixteen days alone and out of radio contact, sleeping in a tent, until the main survey party returned. He continued his work on penguins during this time, writing his Oxford doctoral thesis in Charles Elton’s Bureau of Animal Population.

Sladen moved to the U.S.A. in 1956, initially on a research fellowship, and became a U.S. citizen in 1962. He remained based at Johns Hopkins while commuting to the Antarctic and Arctic for his research.

Adélie Penguin - adult and chick
Sladen's early work was on this species at Hope Bay, 9 miles along the
coast from Brown Bluff on the Antarctic Peninsula where I took these
photographs on 26 January 2005.

Salt-gland secretion in this species was described by Donald S Douglas
in the 1960s.

I am taking video of the tens of thousands of Adélie
Penguins at Brown Bluff

Schmidt-Nielsen K, Jörgensen CB, Osaki H. 1957. Secretion of hypertonic solutions in salt glands. Federation Proceedings 16, 113-114

Schmidt-Nielsen K, Jörgensen CB, Osaki H. 1958. Extrarenal salt excretion in birds. American Journal of Physiology 193, 101-107

Schmidt-Nielsen K, Sladen WJL. 1958. Nasal salt secretion in the Humboldt penguin. Nature 181, 1217-1218