Soil chemistry dynamics of Sus scrofa carcasses with and without delayed Diptera colonization

Abstract

A large percentage of the organic matter in terrestrial ecosystem soil are of plant-origin (e.g., leaf litter, stems, seeds, and fine root exudates) [1]. Because of this, plant litter decomposition receives greater attention in the scientific community [1,2] compared to the decomposition of dead vertebrates, which has been largely neglected [3]. The fate of carcass-derived carbon and nutrients contribution to the ecosystem and its food webs are little understood [4]. Studies on nutrient recycling of human or other vertebrate remains in the soil have only recently emerged in the literature with most published from those researchers with an interest in forensics.Arthropods, especially insects, vertebrate scavengers, and microbes compete for cadaveric resources [5][6][7]. Insects are usually the first to consume a carcass [7,8]. Smaller carcasses, such as rodents, tend to be consumed away from the site that death occurred so that the amount of cadaveric materials entering the soil is expected to be negligible [9]. Adult or large carcasses tend to be consumed in place,

Soil microbial communities and biogeochemistry during human decomposition differs between seasons: evidence from year-long trials

“…In all but winter core soils we observed nitrate concentrations in decomposition soils to decrease below controls during ammonium enrichment in the early phases of decay when soil oxygen dropped below approximately 75%. Once oxygen returned to 70-75% later in decomposition, nitrate concentrations increased, indicating ammonium could be transformed via nitri cation to nitrite and nitrate or nitrous oxide [1,5,11,15,19,24]. It is likely that other anaerobic nitrogen transformations were also occurring during the period of hypoxia (i.e., denitri cation, dissimilatory nitrate reduction (DNRA), and annamox) as have been documented by other studies [1].…”

Soil elemental changes during human decomposition

“…Animal studies consistently report initial increases in soil P across multiple extraction fractions at the onset of decay [ 15 , 16 , 18 , 19 ] as early as day 8 [ 18 ] and 190 ADD [ 16 ]. Following the initial increase, P generally decreased gradually but remained elevated for months or years under animals > 1.5 kg [ 12 , 13 , 18 , 21 , 22 , 24 , 25 , 28 ]. Due to difficulties associated with replication in human decomposition studies, soil P has not been characterized to the same extent for human decomposition, especially longitudinally, so patterns are unclear.…”

“…These nutrient pulses are dispersed throughout the wider ecosystem in a variety of ways: into the atmosphere via gaseous emissions (including volatile organic compounds, or VOCs) [ 1 ], into insects and scavengers which may move materials over large distances [ 2 – 4 ], and into the soil creating ephemeral hotspots of enhanced nutrient cycling and microbial activity [ 5 – 8 ]. Changes to soil biogeochemistry in these hotspots have been described, including pH [ 5 – 20 ], electrical conductivity (EC) [ 6 , 7 , 10 , 12 , 13 , 15 , 17 , 20 , 21 ], organic and inorganic carbon (C) and nitrogen (N) speciation and cycling [ 5 – 15 , 17 – 19 , 21 – 28 ], and soil oxygen [ 7 ]. However, patterns associated with the deposition and cycling of elements other than C and N have not been explored with the same degree of detail.…”

“…Of the remaining elements, total C and N, their organic and inorganic fractions, and their transformation products are the most commonly documented for surface decomposition [ 5 , 7 – 15 , 17 – 19 , 21 – 28 ]. This is followed by the plant nutrients P [ 5 , 10 , 12 , 13 , 15 – 19 , 21 , 22 , 24 – 26 , 28 ] and K [ 9 , 10 , 16 – 18 , 22 , 25 , 28 , 30 ], the latter of which is also an exchangeable soil cation. In contrast, soil changes of other exchangeable cations, Ca, Na, and Mg, have received only general characterization [ 9 , 10 , 16 , 17 , 25 , 26 , 28 , 30 ], and while the presence of S and chloride have been noted, their soil concentration changes are poorly described [ 9 , 10 , 25 ].…”

“…These nutrient pulses are dispersed throughout the wider ecosystem in a variety of ways: into the atmosphere via gaseous emissions (including volatile organic compounds, or VOCs) [1], into insects and scavengers which may move materials over large distances [2][3][4], and into the soil creating ephemeral hotspots of enhanced nutrient cycling and microbial activity [5][6][7][8]. Changes to soil biogeochemistry in these hotspots have been described, including pH [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], electrical conductivity (EC) [6,7,10,12,13,15,17,20,21], organic and inorganic carbon (C) and nitrogen (N) speciation and cycling [5][6][7][8][9][10][11][12][13][14][15][17][18][19]…”