27 February 2006

Some thoughts on Nessie and other musings

I recently watched Deep Sea Detectives on the History Channel, with the episode about the Loch Ness monster. I was struck by many things about the Loch and its physical structure and setup beyond just the entry/exit points and depth. A look at the Loch's physical structure should be able to reveal what is and is not possible there in the way of larger life forms.

First off the Loch Ness was covered by the last glacial period which ended around 10-12,000 years ago, more or less depending upon locale. Like the Great Lakes, Lake Champlain and Finger Lakes in New York State, the Loch was most likely a river channel before the previous ice age very shallow set of interconnected lakes. In particular Lake Champlain has a similar story of a monster in it, called "Champ". These sets of glacially formed lakes all have the similar feature of being under a mile or so of ice during the last glacial period and then serving as an outwash for glacial water as the glaciers retreated, which also served to deepen and widen the basins of each.

The weight of the mass of ice pushed the ground downwards, closer to sea level, and as was seen in the History Channel program, sea life did indeed live in the Loch for some short period of time. And just like all other areas that were covered by the ice sheet, Loch Ness undergoes isostatic rebound and is slowly rising upwards to compensate for the lack of that mass upon it. This can be clearly seen along the gorge leading from Niagara Falls between the US and Canada, in which the sides of the gorge not only get pushed upwards but inwards in response to the rebound. Because of the friable underlying strata of rock the gorge suffers slips and landfalls along the edges beyond what a normal river valley of this kind will undergo. Geologically speaking, the areas once covered by continental glaciers is slowly rising and will suffer minor and erratic earthquakes due to this, with the majority falling under 4 in the open-ended Richter Scale.

So Loch Ness has probably undergone similar uplift at a rate of about 1 inch per year for the last 12,000 years or so and continues to do so. And one would infer that the area is also geologically active because of this, with minor earthquakes barely felt throughout the region. Many animals, including humans, do feel such shaking on a sub-conscious level when it cannot be felt through gross movements, thus causing a bit of unease during such times. The stories from indigenous peoples across areas that have once had glaciers all bespeak of moving spirits, little people and strange happenings going on and many are probably attributable to this phenomenon. But actual, physical lake monsters are a different category altogether and need to be addressed separately from their somewhat spooky surroundings.

Secondly on the list of things is the sustainment of marine life as the ecosystem radically alters in a short period of time. Going from bare rock with ice above it to cold glacial outflow to marine influx and then a slow lifting and salt water outflow is a massive change in environmental conditions for Loch Ness and many other glacial outflow areas. And, most importantly, the creatures in these lakes would have, of necessity, been following the edges of the glacial ice sheets as their preferred habitat. Any creature in these lakes must have been a salt water based animal before entering and then either have the necessary aptations to continue on in fresh water or be a creature with a bi-modal living style able to exist in fresh or salt water with ease.

Third in this is the calorie budget for such a creature. Here large size plays well to the Square-Cube Law also known as Bergmann's Rule. The short of the Square-Cube Law for animals is that as the body size doubles/halves, mass follows a power of 3 and surface area a power of 2. So, take a man-size creature as being 1, with mass of 1 and surface area of 1. Double the man size creature to one of 2, will have a mass of 8 and surface area of 4. Take a half-man sized creatures as 0.5 and the mass will be 0.125 and surface area of 0.25. So large creatures gain mass far faster than surface area, and are thus able to stabilize body temperature as the outflow of heat is restricted to surface area. Similarly small creatures have disproportionately large surface area to mass and lose body temperature quickly and must have a higher energy budget. This is, by nature, a rule of thumb exercise with outliers and anomalies, but serves a general overall schema for determining necessary caloric budget of any life form. Big creatures can eat a lot, digest slowly and move slowly and get along just fine, while tiny creatures must consume large quantities of food in proportion to body mass just to stay alive and thus digest things very quickly.

Fourth, to go along with the above, is the type of heat budget for such a creature. Calories generate food energy available to an animal, and body mass and surface area will determine heat retention and outflow. Reptiles, as 'cold blooded' creatures, depend upon external factors to regulate heat flow. Mammals, as 'warm blooded' creatures generate internal heat and operate over a wider range of temperature zones in a very active condition. Dinosauria do not fit well into either category, having some capability for internal heat generation and continuing to use external sources for heat moderation and loss.

In colder climates reptiles tend to remain sedentary or have a much slower metabolism and only become active when warmed by sunshine or other heat sources. In the desert, reptiles love to snuggle up to warm bodied sleeping mammals, as any hiker waking up to a snake under their tent will attest to. Mammals can vary their activity level and have evolved to be active in day and night, thus making their capabilities very flexible as a class of animals. Dinosauria present an interesting case in that their ability to generate heat outside of muscular activity needs to be taken into account and that in colder climates they would do well with a relatively thin skin and lack of fat layer while a mammal would need such a fat layer as insulation against the climate. Thus, dinosauria, as a class, would have evolved to adapt into such climates and fossil evidence of dinosaurs in arctic climates have been found and validated.

And the Norse peoples, in particular, tell of one serpent, Jormungandr that would fit this bill and fit in with their overall migration seawards during the glacial retreat. Stories and depictions of this creature as *world girdling* could be an exaggeration of an actual creature sighted at the edges of ice packs. And of course all sorts of people have sea monsters, but the Midgard Serpent would fit all the particulars.

By all accounts Nessie and Champie are either Plesiosaurs or Basilosaurs, each having their own proponents based on dinosauria vs. mammalia and looking at their overall body structure as compared to what is reported of the creatures. Either fits the general shape outline, although one would expect that the long-necked attributes of both creatures makes dinosauria a likelier prospect. Until either can be looked at, one final thing needs to be looked at.

Fifth, geographic isolation and the island dwarfing phenomenon. By all accounts, 12,000 years is not enough to allow much in the way of genetic drift, although some recent surveys of biota from Australia are bringing that into question. There, fast post-glacial change in habitat from lush vegetation to desert conditions has caused faster genetic drift due to impacts of changing diet from the ecosystem upon those members able to survive in it. Most die off, causing extinction, but survivors that have a high degree of change and some adaptability will survive and tend to rapidly speciate due to changing conditions. Genetic surveys are calling into question how fast such stressed species adapt as their genetic system undergoes mutation at a disproportionate rate.

What no one has proposed is that a small creature has undergone Island Gigantism, in which isolation of a small creature allows it to grow much larger, thus gaining the benefits of the Square-Cube Law. I am hard pressed to think of anything that could look like the reported Nessie or Champie in miniature... But I am sure that *some* creature might fit this bill in the history of life on this planet.

Still, 12,000 years will not change the morphology over much and such isolation will not change that to a significant degree. Island dwarfing (or in this case lake isolation dwarfing) can operate very quickly as growth ratios will become stunted due to lowered caloric intake. In a short period of time large animals will quickly change growth status to that of smaller sizes while retaining overall morphology. So one would expect that any large size creature migrating into these isolated areas would become smaller in the 12,000 years or so they have been there while still *looking* the same, just smaller. The final sizing would then have to fit inside the *sweet spot* that balances the following conditions:

1) Thermal regulation for heat loss in cold bodies of water.
2) Maximum supportable breeding population or number of individuals that can exist on the calories provided.
3) Maximum supportable body size due to caloric intake.
4) Metabolic rate changes due to overall class of the animal.
5) Aptation or pre-existing capability to exist in both fresh and salt water conditions, and vary diet in such a way as to get necessary amino acids for survival.

Each in turn:

1) Either dinosauria or mammalia can exist in arctic conditions on land and in water. So both pass this hurdle with ease.

2) and 3) are intertwined. However, both depend upon a survey of biota known to exist in Loch Ness and expected quantities of same. Also juvenile and adults may exist on different diets, so there may be some capability to expand the useful biota region for caloric intake downwards to smaller animals. Something a full size adult would pass up either through poor vision or just *not worth the effort * to go after and eat, a more active juvenile might find a tasty meal or snack.

4) Is an interesting adjustment. With Island Dwarfing it can be expected that due to limited habitat the creatures will be smaller than their original ancestors. And the original class of creature will tend to give an idea of how well such a thing can be done. Here there is an advantage to dinosauria as they can use their limited heat regulation capability to up their metabolism a notch with relative ease. A mammal, however, loses fat disproportionately to size and thus has much less insulation per body weight and surface area. Mammals can make a go of it in such conditions, but their long-term survivability from a large size creature would be in doubt. Smaller animals, better adapted harsher extremes and having a proportionate fat to mass ratio would do better than a large creature scaling down. So possible, but less likely.

5) This is the real kicker for any salt-water creature: surviving with a breeding population in fresh water. The ability to do so is buried in the overall genetic toolkit of all vertebrates, so it may be expected to be possible, and some animals do actively live in both. While salmon are the best example, but eels exhibit a similar behavior. Bull sharks have a unique set of kidneys to deal with fresh water, and have been caught a thousand or more miles upriver from oceanic outlets. As both the dinosauria and mammalia use normal lungs to breathe with, filtering of salt is not a factor. Skin, however, is a cause for concern and a type of skin that would function well in salt water may not be suitable to fresh water. And there is also a diet change that would have to be done. In general, if suitable substitutes for their oceanic diets can be found and have sufficient nutrients to continue life without deficeits of amino acids, both should be able to handle the stress of change. There may be some outflow of ions through the skin membrane, and so one would expect that both classes would need to seek out some sources of these ions in their new habitat. This could be as easy as drinking from a stream that flows through a minor salt deposit or finding plants that tend to concentrate those elements necessary for an active nervous system and musculature.

So lets do the quick look at biota in Loch Ness. The place is a fisherman's haven! Luckily others have trod this area very well and have left their marks on looking at what Nessie would dine upon. The list is interesting and extensive:

1) Brown trout (also sea trout)
2) Pike
3) Arctic char
4) Salmon during mid-January to mid-October
5) Eels
6) Sturgeon
7) Catfish and Wels catfish
8) Migrating seals
9) Frogs, newts, toads (juvenile fare, one would expect)
10) Cormorants, ducks, herons (just drift up very slowly underwater and a quick bite for a tidbit... unless your digestive tract cannot handle the bones involved)
11) Non-game fish like perch, roach, dace, rudd and carp; and minnows
12) Deer
13) Otters
14) Vipers, small lizards and slow worms

The question is: does the distribution of fish types and sizes fit with a top predator like an expected Nessie?

The normal distribution that I have seen in freshwater lakes from New York State and Ontario, Canada, fit well with the reports of fishing sizes seen in Loch Ness. The lack of major predators to keep fish sizes down allows for a somewhat larger size to be achieved within the existing populations of fish. Of the two expected predators and some minimum colony size, one would expect there to be a flat distribution of fish sizes at the high end as larger individuals become the preferred food for the predators. At the low end, the somewhat more voracious, but less numerous juveniles would tend to drive smaller fish and their spawn closer to shore as the protective instincts of the adults would herd juveniles away from shoreline.

So, where does this leave the investigation of Nessie and its other monsterly kin?

In one of the strangest places of all: working with statistics.

Without a good demonstration of a large fauna top predator existing via physical evidence, we must look to the environment. If there is a *normal* (as in bell curve) distribution of sizes in the fish population by species, then you have a normal northern climate top predator scenario. Pike and other fishly predators will give a normal distribution by species that they prey upon. A larger top predator will cut the curve nearly flat at the top size distribution and its juveniles will drive smaller fish inshore and flatten out that part of the curve, also. A curve indicating a flatter low sizing and sudden cut-off in high size as compared to similar fish habitat will indicate a top predator culling the high end and its juveniles at the low end.

Show that, and you have a rock-solid demonstration of a top predator even if you do not know what it is. And with all that peat in the water, forget filter feeding as an alternative.

Without it, you gots a normal big cold lake, folks.

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