eDNA and Nessie

I received a phone call from a Sunday Post journalist last week asking for my opinion on an upcoming project at Loch Ness. They have now run this article on attempts to DNA profile the loch using the proven technique of Environmental DNA retrieval or eDNA. Some of my comments appear in the article but I wanted to flesh out some of them here.

The journalist had contacted me through an article I had written three years ago on the search for Nessie carcasses and I had suggested eDNA may be a tool for finding clues to unidentified species in the loch. Coming to the present day, I welcome such a scientific endeavour, even as I did back then. My comments to him with additional thoughts are set out below.

Firstly, the water sampling needs to be planned properly. Loch Ness is the largest body of freshwater in the United Kingdom.  How many water samples have to be taken and where? I note that a similar study done at England's largest lake, Windermere, last year involved more than 60 two-litre samples. Since the water volume of the lake is 314 million cubic metres compared to 7.4 billion cubic metres for Loch Ness, does this mean an equivalent sampling of 1400 buckets will need to be done?

In terms of large, unknown creatures, their biomass will generally be a fraction of the biomass they predate. How does that affect the required sensitivity of the sampling? Also, if they are mainly benthic or littoral residents rather than open water pelagic dwellers, then sample locations have to take this into account.

Secondly, the eDNA experiment would have to prove its worth by detecting those indigenous species we already know about such as Arctic char and European eels. One may even include such things as human DNA from sewage works discharges! But how will the experiment fare when attempting to detect rarer populations such as Pike and Lamprey?

If a known species cannot be detected, then this has to be highlighted as a limit on the experiment. That particular survey on Lake Windermere successfully identified 14 out of 16 of the known resident species. The rarest two were not detected, so it is not perfect, but it is more efficient than live samples using nets.

Thirdly, there is the matter of occasional visitors such as Atlantic salmon, Sea trout and seals. Will their DNA persist in the loch long enough to enable detection? I understand that DNA in water can degrade in a matter of weeks, depending on various factors. Obviously, this has a bearing on the theory that the Loch Ness Monster is actually not indigenous but itinerant and visits the loch in the same manner of seals. In this sense, eDNA is more a technique for monitoring the ebbs and flows of species permanently resident in aquatic regions.

Fourthly, having identified and eliminated known DNA traces from the water samples, what will be left? This is clearly the part that interests everyone the most and would potentially consist of known and unknown DNA samples. It is clear that no one knows what Plesiosaur DNA looks like. A hit on sturgeon DNA would be interesting but is dependent on point three. Indeed, what about the Wels Catfish hypothesis?

Moreover, if Nessie was indeed a giant eel, could this be distinguished from the DNA of the indigenous European eels? It is likely that any DNA that has no clear parallel in available DNA databases could still be placed in a higher taxonomy. So what would we deduce if a DNA sample classified as "reptilian" was found?

Fifthly, there is the side subject of Sedimentary Ancient DNA or sedaDNA. This is an aspect of eDNA which looks for ancient DNA traces in sedimentary deposits and if the sediment is sufficiently deprived of oxygen, allows the resident DNA to survive longer. Where one would obtain such samples is not clear. My thoughts turned to the core samples done by Adrian Shine in years past, but I doubt any DNA in them would have survived to the present day.

In conclusion, those who believe in an itinerant or paranormal Nessie will predict nothing will be found. Those who believe in a giant Nessie eel may not be able to conclusively detect such DNA.  Those who are more sceptical may yet hold out for giant catfish or a surprise sturgeon. My own view is that the creatures are part itinerant and part resident, but the time proportions are not known to me.

For the rest, if the tests are done properly, the idea of a present and continuously breeding, indigenous herd of large predators may yet receive its stiffest test. Note I say "present" as this will give no indication of the past in Loch Ness when any population in the loch may have been higher than it is now.

POSTSCRIPT: Professor Gemmell adds further thoughts in this May 5th article.

POSTSCRIPT 2: It seems the professor needs £100,000 to do this project and aims to raise it through crowdfunding. This could be a major stumbling block ...


The author can be contacted at lochnesskelpie@gmail.com

Text of Sunday Post Article (for archive purposes):

IT is a mystery that has persisted for more than a thousand years.
But now a scientist is hoping to use cutting-edge dino-DNA technology to determine once and for all whether the Loch Ness Monster exists or not.

Professor Neil Gemmell wants to solve the mystery by looking for traces of unusual DNA in the water of the loch.

The study would involve gathering water samples from various locations at different depths of Loch Ness, before analysing them using the same techniques police forensic teams use at crime scenes.
Prof Gemmell, from The University of Otago in New Zealand, believes his scientific study could solve the enduring, world famous monster mystery.

He said: “Our group uses so- called environmental DNA to monitor marine biodiversity. From a few litres of water, we can detect thousands of species ranging from whales, sharks to plankton.
“Essentially all large organism lose cells from their skin, or digestive system, or whatever, as they move through their environment.

“New genomic technology is sensitive enough to pick this up even when rare, and we can use comparisons to large sequence databases that span the majority of known living things. If there was anything unusual in the Loch, these DNA tools would likely pick up that evidence.”

News of the potential DNA study has sent shockwaves through the Nessie-monitoring world.
Researcher and enthusiast Roland Watson, 54, welcomed the study.
He said: “I’m all for scientific inquiry and trying to find this thing by any means we have.
“I’m not aware of anyone having done a DNA test before.

“I’d want to know if the test would be sensitive enough to detect animals that are visitors to the loch, such as seals and Atlantic salmon. The monster could be visiting. There are some monster supporters that would not care about the result because they believe it is something paranormal and so wouldn’t expect to see any DNA.”

Naturalist Adrian Shine is the leader of the Loch Ness Project and has carried out field work on the loch for a host of universities and researchers since 1973. He said he and his team could potentially help gather samples for the study.

He said: “I would be very interested in the results.
“We would certainly be able to help getting samples.”

Steve Feltham has spent 26 years trying to solve the mystery from his base on the shores of the loch. He said: “If anyone thinks they can identify it – bring them on.
“Anything that gives us more knowledge is to be welcomed.”

Steve also said that he wouldn’t give up his hunt even if the study suggested there was nothing there.
He said: “I can guarantee you someone would see something the next day.”
Dores Community Council chairwoman Ella Macrae said she would be interested in the study but said the results won’t change the popularity of the myth.

She said: “The mystery will still be spoken about in decades to come when this study is done.
“I don’t think they will ever get to the bottom of it.”