Landslides vs Archaeology

Landslides are one of the few types of natural hazards that have affected Sweden regularly in the recent past. We can expect that this geological phenomenon will only increase in frequency in the near future given the ongoing processes of anthropogenic climate change, and this likelihood motivates some historical retrospection. This paper explores how landslides have impacted archaeological sites in Västra Götaland, the country’s most landslide-prone region, from the mid-twentieth century onwards, and how, in turn, archaeologists have had to respond to these disasters. The 1957 Göta, 1973 Fröland, 1977 Tuve and 2006 Småröd landslides are highlighted in particular, as is the landslide-impacted site Hjälpesten. Connections are made to other different but related archaeologies of hazard and disaster, providing insights into the impact that climate change has had and will have on the discipline. While the paper showcases a set of local case studies, it is further argued that its findings have relevance for other areas as well, calling for the attention of the cultural heritage sector.

Exploring the plant environmental DNA diversity in soil from two sites on Deception Island (Antarctica, South Shetland Islands) using metabarcoding

The few Antarctic studies to date to have applied metabarcoding in Antarctica have primarily focused on microorganisms. In this study, for the first time, we apply high-throughput sequencing of environmental DNA to investigate the diversity of Embryophyta (Viridiplantae) DNA present in soil samples from two contrasting locations on Deception Island. The first was a relatively undisturbed site within an Antarctic Specially Protected Area at Crater Lake, and the second was a heavily human-impacted site in Whalers Bay. In samples obtained at Crater Lake, 84% of DNA reads represented fungi, 14% represented Chlorophyta and 2% represented Streptophyta, while at Whalers Bay, 79% of reads represented fungi, 20% represented Chlorophyta and < 1% represented Streptophyta, with ~1% of reads being unassigned. Among the Embryophyta we found 16 plant operational taxonomic units from three Divisions, including one Marchantiophyta, eight Bryophyta and seven Magnoliophyta. Sequences of six taxa were detected at both sampling sites, eight only at Whalers Bay and two only at Crater Lake. All of the Magnoliophyta sequences (flowering plants) represent species that are exotic to Antarctica, with most being plausibly linked to human food sources originating from local national research operator and tourism facilities.

Diversity of Pteridophyte Flora in Rajamala, Eravikulam National Park, Kerala, India

Aims: To enumerate the fern diversity in the disturbed landscapes of Rajamala part of Eravikulam National Park, Western Ghats Study Design: Purposive sampling method was adopted in the study area and habitats suitable for ferns were surveyed. Place and Duration of Study: The study area is Rajamala, a tourist impacted site inside Eravikulam National Park in Kerala, India. Intensive field explorations were carried out in this area during February 2018- April 2019, to document the ferns and fern-allies. Methodology: A preliminary study was conducted in February 2018 to identify the probable habitats of ferns for further detailed study. Purposive sampling was done in the study area considering the most suitable habitats in both shola ecosystems and grassland ecosystems of the area. Materials for herbaria were processed using standard methods. The collected plants were identified with the help of standard field guides and flora. The potential medicinally important ferns were also listed out. Results: 54 species of pteridophytes including fern and fern allies belonging to sixteen different families were found from the Rajamala region of Eravikulam National Park. Aspleniaceae was the most common family with 11 species followed by Polypodiaceae. The majority of the Pteridophytes found in the region are showing terrestrial habit. Eleven species found in the study site are medicinally important. Conclusion: Despite the high tourism pressure in the study area, pteridophyte species richness is higher in the Rajamala region of Western Ghats. The suitable habitat with ideal substrate conditions and year-long moisture availability in the substrates could be the reason for a higher number of pteridophyte species in this area.

Compositional and Functional Microbiome Variation Between Tubes of an Intertidal Polychaete and Surrounding Marine Sediment

The decorator worm Diopatra cuprea, a tube-forming marine polychaete common to intertidal and shallow subtidal waters, modifies habitats it occupies through microreef construction and algal gardening. While several studies have demonstrated that decorator worm tubes are hotspots of biogeochemical activity (i.e., nitrogen and sulfur cycling), it is still largely unclear whether the tube microbiome differs compositionally from the surrounding sediment and what distinct functional processes tube microbiomes may have. To address these unknowns, this study analyzed the bacterial communities of D. cuprea tubes and surrounding sediments using high-throughput 16S rRNA gene amplicon sequencing. Tubes and sediments were sampled at three sites along an anthropogenic stress gradient within the Newport River Estuary to also assess geographic variation of tube microbiomes and the possible influence of human disturbance. We found a clear distinction in the microbial community composition and diversity between tubes and surrounding sediment. Tube microbiomes were significantly enriched for the phyla Bacteriodetes, Actinobacteria, Verrucomicrobia, Deferribacteres, Latescibacteria, and Lentisphaerae. Chloroplast sequences of macroalgae and grass species were consistently abundant in tubes and nearly absent in surrounding sediment. Functional annotation of prokaryotic taxa (FAPROTAX)-based functional predictions suggested that tube microbiomes have higher potentials for aerobic chemoheterotrophy, sulfur compound respiration, nitrate reduction, methylotrophy, and hydrocarbon degradation than surrounding sediments. Tube microbiomes vary across sites, though dissimilarity is comparatively low compared to tube-to-sediment differences. Contrary to our hypothesis, the tubes at the most highly impacted site had the highest microbial diversity [i.e., amplicon sequence variant (ASV) richness and Shannon’s diversity], yet tubes from the medium impacted site actually had the lowest microbial diversity. Our findings show that D. cuprea tubes support a microbiome that is significantly distinct in composition and function from the surrounding sediment. Diopatra cuprea tubes appear to create unique microhabitats that facilitate numerous microbially-mediated biogeochemical processes in the marine benthic environment.

Stable isotopes track the ecological and biogeochemical legacy of mass mangrove forest dieback in the Gulf of Carpentaria, Australia

A combination of elemental analysis, bulk stable isotope analysis (bulk SIA) and compound-specific stable isotope analysis of amino acids (CSIA-AA) was used to assess and monitor carbon (C), nitrogen (N) and sulfur (S) cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–2016, attributed to an extreme drought event. Three field campaigns were conducted 8, 20 and 32 months after the event over a period from 2016 to 2018 to obtain biological time-series data. Invertebrates and associated organic matter including mangroves and sediments from the impacted ecosystem showed enrichment in 13C, 15N and 34S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding and algae feeding were more 13C enriched at the impacted site, by 1.7 ‰–4.1 ‰, and these differences did not change over the period from 2016 to 2018. The CSIA-AA data indicated widespread 13C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. The seedling density increased from 0.2 m−2 in 2016 to 7.1 m−2 in 2018 in the impacted forest, suggesting recovery of the vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest is required to predict the long-term trajectory of ecosystem recovery. This study shows that time-series SIA can track biogeochemical changes over time and evaluate recovery of an impacted ecosystem from an extreme event.

GEOCHEMICAL ASSESSMENT OF TRACE METALS IN SOIL, STREAM WATER AND SELECTED FOOD CROPS AT KIBI GOLDFIELDS ENVIRONMENT, GHANA

This study assesses environmental receptors impacted by alluvial gold mining at Kibi Goldfields Limited in the Eastern region of Ghana to establish trace metals contamination risk. Specific objectives are to determine concentrations of (1) As, Cr, Ni and Pb in soils, drainage and food crops, using X-ray fluorescence, (2) Cl- in drainage using standard methods. Mean concentrations of As, Cr and Ni in soils are higher at impacted sites than control sites; while Pb and As concentrations in drainage exceeds the maximum contamination guideline values in drinking water. Using Cl- as a conservative tracer, As and Pb are adsorbing from water, while Cr and Ni are desorbing into water. In the food crops, bioaccumulation factors of As and Ni are profound at the impacted site than control sites; Except Cr in cocoyam at impacted sites, translocation factors are negligible in the food crops. Cr bioaccumulates in in cocoyam and plantain at the control site, while Ni bioaccumulates in only plantain at the impacted sites. Overall, the metal contamination is of concern in the receptors, except Pd in plants. Results from this study can be used for trace metals risk assessment in the environment.

SAT-LB131 Examination of Hepatic Gene Expression Following Developmental Exposure to Dieldrin in Trachemys Scripta and Discovery of a Novel Hepacivirus

The Massachusetts Military Reservation (MMR) is a Superfund site where ground water has been contaminated by a mixture of pollutants. Exposure to these chemicals is a public health concern and reproductive impairments have been observed in a population of turtles (Chrysemys picta) endemic to this site. We hypothesize that developmental exposure to endocrine disrupting compounds originating from the MMR might lead to abnormalities seen in adult animals. Upon examination of egg yolk from turtles at the impacted site, we found the presence of dieldrin and p,p’-DDE. Turtles from a reference site were also found to have p,p’-DDE present in the yolk. In order to investigate these chemicals in the laboratory we used a closely related turtle (Trachemys scripta) and applied vehicle, dieldrin, or p,p’-DDE to the eggshells. Absorption of p,p’-DDE through the eggshell was limited. Although there were variations in absorbance, we were able to achieve levels of dieldrin in the yolk similar to what was seen in animals from the impacted site. Following in ovo exposure to dieldrin, we used RNAseq to examine hepatic gene expression in neonates and found that several transcripts were repressed at least 1.5-fold in the dieldrin-treated animals. QPCR was carried out to confirm differences in gene expression. We found that hepatic gene expression (fold ± SEM) of Gamma-Butyrobetaine Hydroxylase 1 (Bbox1) was higher in vehicle-treated animals (1 ± 0.60) compared to dieldrin-treated animals (0.29 ± 0.12). Bbox1 catalyzes the last step in the L-carnitine biosynthetic pathway, which is necessary for mitochondrial beta-oxidation. Dieldrin-induced reduction in L-carnitine production may be a critical factor in adult reproductive function. Further, Protein-L-Isoaspartate (D-Aspartate) O-Methyltransferase Domain Containing Protein 1 (Pcmtd1) was higher (1± 0.76) in vehicle-treated animals compared to dieldrin-treated animals (0.13 ± 0.044), and DENN Domain Containing 5B (Dennd5b) was also found to be higher in vehicle-treated (1 ± 0.39) compared to dieldrin-treated (0.28 ± 0.10) turtles. We found that dieldrin exposure did not alter gene expression of Cytochrome p450 1a (Cyp1a) a marker of aryl hydrocarbon receptor signaling, or Vitellogenin 2 (Vtg2) a marker of estrogen signaling. In our RNAseq analysis we unexpectedly discovered a hepacivirus infecting T. scripta. In the dieldrin-treated group, we used QPCR to examine gene expression of potential markers of hepacivirus infection. Neither Interleukin 1 Beta (Il-1β), SMAD Family Member 6 (Smad6), C-C Motif Chemokine Ligand 5 (Ccl5), or TNF Receptor Superfamily Member 9 (Tnfrsf9) was found to differ in turtles carrying the virus, compared to non-infected animals. In conclusion, we found that developmental dieldrin exposure of T. scripta slightly reduces neonatal expression of several gene transcripts which may be correlated to adult reproductive fitness.

Stable isotopes track the ecological and biogeochemical legacy of mass mangrove forest dieback in the Gulf of Carpentaria, Australia

A combination of elemental analysis and stable isotope analysis (SIA) was used to assess and monitor C, N and S cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–16, attributed to an extreme drought event. Three field campaigns were conducted over a period from 2016 to 2018, at 8, 20 and 32 months after the event. Samples including invertebrates, mangroves, and sediment were analysed for CNS elemental and isotopic compositions including compound-specific stable isotope analysis (CSIA) of amino acid carbon. Samples collected from the impacted ecosystem were enriched in 13C, 15N and 34S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding, and algae feeding were more 13C enriched at the impacted site, by 1.7–4.1 ‰ and these differences did not change over the period from 2016 to 2018. The CSIA data indicated widespread 13C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. Mangrove seedling and sapling populations increased substantially from 2016 to 2018 in the impacted forest, suggesting recovery of the mangrove vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest would help to predict the long-term trajectory of ecosystem recovery. In such long-term monitoring programs, SIA that can track biogeochemical changes over time can help to detect underlying biological mechanisms that drive changes and recovery of the mangrove ecosystem. To gain further insight, our use of CSIA can help show feeding dependencies in mangrove food webs and their response to disturbances.

Spatio-temporal variation in rate of carbonate deposition by encrusting organisms in different reef microhabitats from Eastern Pacific coral reefs

Reef encrusting calcifiers (non-scleractinian species) constitute assemblages that participate in the carbon cycle at coral reefs. Despite their apparent secondary role in building the reef framework, they contribute to the reef consolidation binding sediments and inducing larval recruitment from other epilithic invertebrates. The contribution of encrusting calcifiers on reef accretion was examined by the assessment of their rate of carbonate deposition on four different simulated reef microhabitats using calcification accretion units (CAUs) during 12 months at Playa Las Gatas and Islote Zacatoso, two coral communities from the coast of the Mexican Pacific. Encrusting calcifiers from Playa Las Gatas, the most impacted site, showed a rate of carbonate deposition (mean ± SD) four times higher than at Islote Zacatoso (10.02 ± 3.22 g CaCO3 m−2 d−1vs 2.48 ± 1.01 g CaCO3 m−2 d−1). Overall, the rate of carbonate deposition on surfaces protected from sedimentation and light was up to 1.8 times higher than on exposed ones (11.40 ± 4.35 g CaCO3 m−2 d−1vs 6.18 ± 3.13 g CaCO3 m−2 d−1). Carbonate deposition by calcareous algae was higher on the well-lit exposed surfaces while filter-feeding invertebrates showed the major contribution on the shaded cryptic surfaces. Although rate of carbonate deposition by encrusting calcifiers seems to be lower than hermatypic corals, it seems to be relevant on coral reefs affected by anthropogenic impacts where coral calcification is low. Under global demise of coral reefs by environmental degradation and climate change, encrusting calcifiers may become relevant for the process of carbonate deposition.