Movement of Bodies in Lake Ontario

TYLER G. O’BRIEN

Introduction

This paper explores the use of information about the effects of wind, temperature, and themovement of lake water as it may affect human remains. One focus is to understand thepotential for the movement of human bodies in a lake environment using limnological models.A second focus is on the environmental limits for the formation of adipocere in aquaticsettings. By way of illustration, a case study is presented of an unidentified adipociferous bodyfound on the shores of Lake Ontario for which the possibility of multiple taphonomic path-ways limits the estimation of postmortem interval.

Lake Effects

A typical lake passes through four phases which may be broken down into two distinctcategories: the overturn cycle and the stratified cycle (Boyce et al. 1989, 1991; Hough 1958;Pickett 1977; Simons and Schertzer 1987).

In the spring, due to winds and the resultant current action, the water is in upheaval. Inearly spring, shallower water near shore warms more rapidly. This rise in temperature causesthe warmer water to migrate away from shore, converge with colder offshore water, and sink.This overall turbidity is known as the “spring overturn.”

After the convergence, the water becomes differentially warmed due to mixing (Boyceet al. 1989, 1991). The onshore water temperature increases above 4˚C. and, due to its higherdensity, sinks, gradually increasing the overall lake temperature. In addition, the onshore/off-shore pressure gradient pushes warm water offshore. The effect of mixing is countered by theearth’s rotational force, known as the Coriolis effect. Coupled with the wind, the water tendsto deflect the waves to the right of the wind, setting up a counterclockwise pattern of surfacemovement. A floating object within such a pattern would be affected by centrifugal force,causing it to move away from the center and toward shore (Boyce et al. 1989). Winds blowingacross the center of the lake will additionally force the nearshore water along until it reachesthe end of the lake, meets the currents from the other side, and they converge. Their directionnow moves toward the center of the lake opposite the wind direction. This sets up a cyclewhere surface water warms and subsurface water cools to 4˚C. The combined result of theCoriolis effect and wind provides enough force for upwelling to occur on one shore anddownwelling on the opposite shore.

In Lake Ontario, the spring upwelling occurs on the northeast shore and the downwellingon the southeast (Simons and Schertzer 1987). The modifications of the upwelling anddownwelling circulation depend on the lake’s thermal stratification and basin geometry (Boyceet al. 1989).

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The second phase of lake effects occurs in the summer when the water is stratified intoan upper (epilimnion) layer and a lower (hypolimnion) layer (Hough 1958). A convectioncurrent from blowing winds moves surface water in a counterclockwise direction, due to theCoriolis effect. A thermocline continues to separate the warmer, low density water on topfrom the cooler, higher density water on the lake bottom (Boyce et al. 1989, 1991). Weatherconditions are the major factor determining the depth of each layer.

Large-scale currents are restricted to the epilimnion, while the hypolimnion remainsinsulated from the atmosphere and the air–water interface. But, due to the circulation of theoverlying layer, the shearing force against the cooler, lighter water moves it in a directionagainst the epilimnionic flow. Thus, the lower stratum maintains motion, while wind forcefrom storm surges keeps the surface water circulating (Boyce et al. 1991).

By the end of summer, the shore water warms again, convection disrupts the thermalbar, and the “fall overturn” is produced (Hough 1958). The overturn is primarily due todestabilization of the water column. It is followed by the “winter stratification” phase, a patternsimilar to that following the spring overturn.

Lake Ontario, the most easterly of the Great Lakes, has a long axis approximately parallelto prevailing winds. Its mean depth is about 86 m, and its maximum depth reaches 245 m(Boyce et al. 1989). A major influx of freshwater comes from the Niagara River located in thesoutheast corner of the lake. The mean monthly discharge of the Niagara River ranges from3289 to 7590 m/s and furnishes about 83% of the total annual input (Aubert and Richards1981). Particulate matter entering the lake will tend to be isolated into weight components,with the heavier, coarser particles settling to the bottom nearer the river (Boyce et al. 1991).Only forces such as storm surges produce enough power to resuspend these particles andflush them into the current.

Adipocere Formation

The formation of adipocere in aqueous environments has been documented by Cotton et al.(1987), Dix (1987), Mant (1960), Mant and Furbank (1957), O’Brien (1994), Simonsen(1977), and Takatori and Yamaoka (1977). Complete transformation of all soft tissues toadipocere in water settings may occur in as little as 3 weeks, and has also been documentedin cases up to 5 years after death (see Table 1).

Table 1 Case Reports Citing Bodies Found with Adipocere

Author (Year) Environment Time Period Condition

Cotton et al. (1987) Water 5 years CompleteMant and Furbank (1957) Water 1 year CompleteDix (1987) Water 10 months CompleteDix (1987) Water 6 months ModerateTakatori and Yamaoka (1977) Water 4.5 months CompleteDix (1987) Water 4 months SlightMellen et al. (1993) Water (lab) 2.5 months CompleteDix (1987) Water 3 weeks MinimalSimonsen (1977) Water 3 weeks CompleteEvans (1962) Buried 100–140 years CompleteRodriguez and Bass (1985) Buried 1 year CompleteRodriguez and Bass (1985) Buried 6 months ModerateRodriguez and Bass (1985) Buried 3 months MinimalRodriguez and Bass (1985) Buried 2.5 months Slight

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Adipocere formation occurs within a limited temperature range, generally tied to theoptimum growth temperature for the bacterium Clostridium perfringens (welchii) (Corry1978; Cotton et al. 1987; Payne and King 1972; Tomita 1975). Tomita (1975) notes the lowerlimit is 21˚C, Corry (1978) reports the optimum temperature is about 45˚C, and Bryan et al.(1962) reports the optimum at 35 to 37˚C. When the ambient temperature reaches a maximumor minimum, adipocere will not form due to a depression in the rate of bacterial action andenzymatic release.

The temperature range must be “just right,” a requirement termed the “Goldilocks phe-nomenon” (O’Brien 1994). When the water is too warm the tissues liquefy easily and tend tomacerate. Soft tissue cells autolyze, subcutaneous adipose deposits melt, and the leaking fluidadds to the liquefaction of all tissue. The soft tissue will decompose rapidly. If the water istoo cold, decomposition slows, and, if the water is freezing, all bodily fluid will freeze andcrystallization will commence (Zugibe and Costello 1993). When the temperature is moderate,the body will decompose and putrefaction will ensue. Bacteria will emerge from their intestinaland vascular lodging to penetrate the body’s cellular network and destroy it. Subsequentrelease of the internal cell’s mass will cause a chemical reaction (i.e., saponification) betweenthe bacteria, the watery environment, and the cellular contents resulting in adipocere. Overtime it accumulates, encasing the bacteria until they eventually die or until there is no moresoft tissue to hydrolyze. The body can remain in this state of preservation for an indefiniteinterval (Bass 1984, Evans 1962). Even if brought to the surface, the adipocere will maintainits consistency. If allowed to dry, the transformed tissue will become a saponified, caseousmass of crumbling, chalky “soap.”

Adipocere Formation and Postmortem Interval

Gonzales and co-workers (1954), Spitz and Fisher (1980), and Taylor (1965) state that thecomplete adipocere transformation of soft tissue can occur in about 3 to 6 months. However,Simonsen (1977) has documented extensive adipocere formation appearing within only 22 days.

A study of adipocere formation in an aquatic environment was conducted by O’Brien(1994). Three human cadavers were immersed in excavated water-filled holes for three monthsin an outdoor setting. Observations were made of climatological and meteorological condi-tions, ambient air and water temperature, and gross morphological changes in the cadavers.Liquid and tissue samples extracted at intervals during the study were analyzed for fatty acidcontent and microbial composition. Not surprisingly, the study confirmed that a warm (21to 45˚C.), moist, virtually anaerobic environment is suitable for adipocere formation, andthat 3 months is sufficient time. Less expected were the results that the two bodies whichformed adipocere were also the ones that floated the entire time of the study. Thus, completeimmersion was neither necessary nor sufficient. The progression of morphological changewhich occurred in these two bodies was as follows: float, bloat, insect activity, hatching,mummification/maceration, fungal growth, color loss, cutis anserina, and then adipocereformation.

Case Description

On April 8, 1992, the Onondaga County Medical Examiner’s Office in Syracuse, New York,recovered a body from a rocky shore of Lake Ontario behind the Alcan Aluminum Plant inOswego. The partial body, found on the rocks in a supine position, with the head orientedto the east, was in an advanced state of decomposition with partial skeletonization of limbsand skull. No clothing was present except the elastic waistband from a pair of men’s briefspositioned around the waist.

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Extensive abrasion was noted on the labial surface of the left maxillary canine, exposingdentin, on the nasal bones, the nasal aperture, the nasal spine, and the exposed frontal sinuses.The medial and lateral malleoli of the distal tibiae and fibulae were missing and the distalshafts eroded (see Figure 1). The right distal humerus showed a similar pattern; medial and lateralepicondyles were missing, probably due to erosion. Despite the distal humerus erosion, soft tissuekept the radius and ulna attached. Bones of the right hand and both feet were absent. Tissuecomprising the cheeks, lower neck, thorax, abdomen, and upper legs had been transformed intoadipocere; the abdominal cavity had been perforated, exposing internal organs. Although noexternal genitalia remained, the prostate was discernible at autopsy (Germaniuk 1992).

There are multiple fractures of all ribs; however, the lack of focal accumulation of bloodin the surrounding soft tissue suggests they were sustained after death. A posterior occipitalfracture which extends between the temporal bones could be peri- or postmortem, and maybe due to impact on the rocks with the action of the waves or other causes.

An estimated postmortem interval was developed using a taphonomic approach, includ-ing the abrasion of long bones and face, meteorological data for the weeks prior to discoveryof the body, models of lake water movement, and inferences regarding adipocere formation.

Abrasion

The location and position of the body suggests the focal abrasion on the long bones andcranium may be a result of abrasion by rocks rather than water. The action of waves pushingthe appendages back and forth against the rocks would have been sufficient to produce suchlocalized soft tissue and bone loss. If the body had been trapped below the ice shelf or brokenice blocks it would have been subjected to damage due to solid abrasive matter containedwithin the ice itself (Boyce et al. 1989). Rock fragments, wood, silt, and sand may all be heldwithin the ice layers (Fahnestock et al. 1973).

Meteorological Data

Environmental data at the Alcan Aluminum Plant provided current meteorological informa-tion about air temperature, wind speed, and wind direction for the week prior to recovery.

Figure 1 (A) Posterior aspect of left humerus; (B) posterior aspect of distal right humerus; (C)anterior aspect of distal right tibia and fibula; (D) anterior aspect of distal left tibia and fibula.Unmarked areas represent portion which was missing; speckled areas represent sites of erosion.

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Air temperature 9.1 m from shore ranged from 17.2 to 31.7˚C, while lake temperatures rangedmore narrowly from 19.4 to 21.8˚C. Both high temperatures occurred the day before discovery.Weather reports stated conditions were “mostly sunny, breezy and cool” (Niagara MohawkPower Corporation 1992).

Multiple Taphonomic Pathways

The condition of the remains reported earlier suggests multiple taphonomic processes: abra-sion due to sand-imbedded ice; skeletonization and disarticulation due to decomposition andwater movement; and adipocere formation due to relatively warm, moist, anaerobic condi-tions. The timing and, to some extent, the sequence of these events is unknown, however.

Information about meteorological conditions and particularly lake effects suggests thatthe lake contains multiple depositional environments which vary according to depth, distancefrom shore, and season. Additional variation is added with consideration of weather and theproximity to the factory’s effluent. Information from the literature about the formation ofadipocere suggests it can form in as little as 3 weeks time, that its formation is temperaturesensitive, and that it can form in bodies which float.

Examination of the context of discovery of the body suggests that the conditions at thatlocation at that time of year are sufficient to explain the presence of localized and position-dependent bone abrasion as well as the presence of both wet and dried adipocere. Theformation of the adipocere would probably have required a less aerobic microenvironment,and hence the body is hypothesized to have arrived at that location via lake current. Further,judging from the extent of the adipocere, the body most likely became located in a fairlystable, anaerobic setting, either floating or submerged, prior to extensive decomposition, andstayed there at least several weeks and probably longer.

Given the temperature-sensitive nature of adipocere formation as well as the fact that theoff-shore hypolimnion tends to be quite cold during all seasons, if the body had been sub-merged at that depth, both decomposition and adipocere formation would have been delayed,suggesting a longer postmortem interval would be more likely, perhaps even years. Alterna-tively, adipocere could have formed more quickly in the warmer waters near the surface andnear the shore, assuming the body was protected from predators and excessive aeration as itfloated (or was caught and held in place at a shallow depth). In that case, the postmorteminterval might have been shorter, perhaps months. In the absence of further data, however,one cannot choose between these two plausible scenarios.

Summary

Lake Ontario provides a complex range of depositional environments for both floating andsubmerged remains. And, despite a number of studies of adipocere formation, many unknownspersist about this important postmortem process. Nevertheless, knowledge about the optimumconditions for adipocere formation, as well as documentation about its formation in floatingremains, helped shape the taphonomic interpretation as well as the estimation of postmorteminterval the case presented here. The limits of this interpretation point to a continuing need forsystematic documentation of both the context of discovery and the condition of remains in futureforensic cases in order to understand the range of variation of postmortem changes in aquaticsettings, and ultimately increase of the accuracy of postmortem interval estimates.

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