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Taphonomy is the study of decaying organisms over time and their process of fossilization. Taphonomy, originally a branch of palaeontology and anthropology, was developed to understand the ecology of a decomposition site, how site ecology changes upon the introduction of plant or animal remains and, in turn, how site ecology affects the decomposition of these materials. In recent years, these goals were incorporated by forensic science to understand the decomposition of human cadavers, to provide a basis on which to estimate postmortem and/or postburial interval, to assist in the determination of cause and circumstances of death, and to aid in the location of clandestine graves. These goals are achieved through the study of the factors that influence cadaver decomposition (e.g. temperature, moisture, insect activity). These studies have also provided insight into the belowground ecology of cadaver breakdown and allowed to develop useful protocols for mass disaster managements in humanitarian medicine. From the results obtained, new scientific disciplines have arisen, gathered under the word “taphonomics” such as the study of microorganisms living below/on a cadaver (thanatogeomicrobiology), and join the more classical forensic sciences such as anthropology, botany or entomology. Taking into account the specificities of the study object (human cadaver), primordial requirements are needed in terms of security (physical and environmental) as well as ethical and legal concerns which are studied in the Swiss context. The present review aims to present in a first part the concept of human forensic taphonomy facilities (HFTF, also colloquially named “body farm”) leading to an enrichment of forensic sciences with new “taphonomics”. The second part is focused on the mandatory points that must be addressed for a HFTF approach, especially because it requires a specific place to undertake this research which must be performed in conformity with a country’s human ethics and laws.

Ecological zonation of salt marsh macrophytes is strongly influenced by hydrologic factors, but these factors are poorly understood. We examined groundwater flow patterns through surficial sediments in two salt marshes in the southeastern United States to quantify hydrologic differences between distinct ecological zones. Both sites included tall- or medium-form Spartina alterniflora near the creek bank; short-form Spartina alterniflora in the mid-marsh; salt flats and Salicornia virginica in the high marsh; and Juncus roemarianus in brackish-to-fresh areas adjacent to uplands. Both sites had relatively small, sandy uplands and similar stratigraphy consisting of marsh muds overlying a deeper sand layer. We found significant hydrologic differences between the four ecological zones. In the zones colonized by S. alterniflora , the vertical flow direction oscillated with semi-diurnal tides. Net flow (14-day average) through the tall S. alterniflora zones was downward, whereas the short S. alterniflora zones included significant periods of net upward groundwater flow. An examination of tidal efficiency at these sites suggested that the net flow patterns rather than tidal damping controlled the width of the tall S. alterniflora zone. In contrast to the S. alterniflora zones, hypersaline zones populated by S. virginica were characterized by sustained periods (days) of continuous upward flow of saline water during neap tides. The fresher zone populated by J. roemarianus showed physical flow patterns that were similar to the hypersaline zones, but the upwelling porewaters were fresh rather than saline. These flow patterns were influenced by the hydrogeologic framework of the marshes, particularly differences in hydraulic head between the upland water table and the tidal creeks. We observed increases in hydraulic head of ~40 cm from the creek to the upland in the sand layers below both marshes, which is consistent with previous observations that sandy aquifers below fine-grained marsh soils act as conduits for flow from uplands to tidal creeks. This hydrologic framework supports relatively good drainage near the creek, increased waterlogging in the mid-marsh, and the development of hypersalinity adjacent to the freshwater upland. These hydrologic differences in turn support distinct ecological zones.

Submarine groundwater discharge (SGD) supplies nutrients, carbon, metals, and radionuclide tracers to estuarine and coastal waters. One aspect of SGD that is poorly recognized is its direct effect on dissolved oxygen (DO) demand in receiving waters, denoted here as SGD-OD. Sulfate-mediated oxidation of organic matter in salty coastal aquifers produces numerous reduced byproducts including sulfide, ammonia, dissolved organic carbon and nitrogen, methane, and reduced metals. When these byproducts are introduced to estuarine and coastal systems by SGD and are oxidized, they may substantially reduce the DO concentration in receiving waters and impact organisms living there. We consider six estuarine and coastal sites where SGD derived fluxes of reduced byproducts are well documented. Using data from these sites we present a semiquantitative model to estimate the effect of these byproducts on DO in the receiving waters. Without continued aeration with atmospheric oxygen, the study sites would have experienced periodic hypoxic conditions due to SGD-OD. The presence of H 2 S supplied by SGD could also impact organisms. This process is likely prevalent in other systems worldwide.

Background Corals are known for their symbiotic relationships, yet there is limited evidence of chemoautotrophic associations. This is despite some corals occurring near cold seeps where chemosymbiotic fauna abound including mussels that host sulfur-oxidizing chemoautotrophs from the SUP05 cluster (family Ca. Thioglobaceae). We investigated whether corals near cold seeps associate with related bacteria and report here that these associations are widespread. Results We screened corals, water, and sediment for Thioglobaceae using 16S metabarcoding and found ASVs associated with corals at high relative abundance (10 – 91%). These ASVs were specific to coral hosts, absent in water samples, and rare or absent in sediment samples. Using metagenomics and transcriptomics, we assembled the genome of one phylotype associated with Paramuricea sp. B3 (ASV 4) which contained the genetic potential to oxidize sulfur and fix carbon, and confirmed that these pathways were transcriptionally active. Furthermore, its relative abundance was negatively correlated with the stable isotopic composition of its host coral’s tissue suggesting some contribution of chemoautotrophy to the coral holobiont. Conclusions We propose that some lineages of Thioglobaceae may facultatively supplement the diet of their host corals through chemoautotrophy at seeps or may provide essential amino acids or vitamins. This is the first documented association between chemoautotrophic symbionts and corals at seeps and suggests that the footprint of chemosynthetic environments is wider than currently understood.

The Gulf of Mexico is a place where the environment and the economy both coexist and contend. It is a resilient large marine ecosystem that has changed in response to many drivers and pressures that we are only now beginning to fully understand. Coastlines of the states that border the Gulf comprise about half of the US southern seaboard, and those states are capped by the vast Midwest. The Gulf drains most of North America and is both an economic keystone and an unintended waste receptacle. It is a renowned resource for seafood markets, recreational fishing, and beach destinations and an international maritime highway fueled by vast, but limited, hydrocarbon reserves. Today, more is known about the Gulf than was imagined possible only a few years ago. That gain in knowledge was driven by one of the greatest environmental disasters of this country’s history, the Deepwater Horizon oil spill. The multitude of response actions and subsequent funded research significantly contributed to expanding our knowledge and, perhaps most importantly, to guiding the work needed to restore the damage from that oil spill. Funding for further work should not wait for the next major disaster, which will be too late; progress must be maintained to ensure that the Gulf continues to be resilient.

Documenting anaerobic microbial metabolisms in hypersaline perennially ice-covered lakes in Antarctica further refines the environmental limits to life and may reveal rare biogeochemical mechanisms and/or novel microbial catalysts of elemental cycling. We assessed rates of sulfate reduction, methanogenesis, and anaerobic oxidation of methane using radiotracers and generated 16S rRNA gene libraries from the microbial communities inhabiting the deep calcium-chloride-rich brine and sediments of Lake Vanda, McMurdo Dry Valleys, Antarctica. Sulfate reduction rates were observed in surface sediments but not in the brine overlying the sediments. Methane formation through the methylotrophic, acetoclastic, and hydrogenotrophic pathways was quantified using 14C-labeled methylamine, acetate, and CO₂, respectively, and methanogenesis was detected in both the brine and the sediments. Hydrogenotrophic methanogenesis rates were the highest of all substrates tested in the sediments, while methylotrophic methanogenesis was highest in the brines. Anaerobic oxidation of methane was below the limit of detection in both the brines and sediments. The major taxa of Bacteria and Archaea detected were most similar to organisms previously observed in hypersaline environments and included examples related to known sulfate-reducing bacteria other than Deltaproteobacteria (surprisingly, sulfate-reducing Deltaproteobacteria were not observed in this study), and both methanogenic and methanotrophic Archaea. These data indicate an active microbial community in the anoxic brine of Lake Vanda that while similar in terms of community structure and metabolism to other brine habitats, is uniquely evolved to survive in this extreme environment.

We discovered a hotspot of elevated nitrate concentration (median = 431 μM) in shallow beach pore water that extended across the entire length of two barrier islands in the southeastern United States of America. We investigated this feature by surveying groundwater geochemistry, measuring fluctuations in in situ dissolved oxygen (DO) concentrations, modeling groundwater flow, and quantifying nitrification rates. Nitrification of groundwater ammonium was the only possible nitrate source, with a measured potential rate of 0.84 μmol m-2 h-1. However, the observed nitrate concentrations were far in excess of the predicted maximum achievable by aerobic nitrification assuming a 2 : 1 ratio of O : N and around 200 μM DO in air-saturated seawater. Groundwater DO concentrations within the hotspot (65 cm depth) were consistently 20–50 μM. The nitrate hotspot was located at the top of the water table beneath dry, undersaturated sand that allowed the penetration of air and the dissolution of excess oxygen into the pore fluids. The total dissolved nitrogen concentration of the hotspot was higher than anywhere else on the island, indicating nitrogen accumulation within the hotspot, most likely via ammonium adsorption. Vertical dispersion was the dominant pathway for nitrate loss from the hotspot. This nitrate was consumed in underlying anoxic sand, coupling microbial pathways of nitrogen oxidation and reduction and removing bioavailable nitrogen from the beach ecosystem.