Organic geochemical characterization of Early-Mid-Holocene swamp deposits near the Neolithic settlement in Yenikapı-Istanbul: Assessment of environmental variability and anthropogenic impacts

The Holocene ◽  
2021 ◽  
pp. 095968362110331
Author(s):  
Mehmet Namık Yalçın ◽  
Heinz Wilkes ◽  
Birgit Plessen
Keyword(s):  
Organic Matter ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Anthropogenic Impacts ◽  
Hydrological Regime ◽  
Climatic Conditions ◽  
Neolithic Period ◽  
Age Model ◽  
Isotopic Characterization

During the archaeological excavations in the Byzantine Theodosian harbor (Istanbul) a Holocene dark gray to black clay sequence was uncovered. This clay unit was deposited under anoxic conditions in a small swamp. Both wooden artifacts from the Neolithic period, but also dispersed organic matter were perfectly preserved within this sequence. The aim of this study was the assessment of environmental changes and anthropogenic impacts with the help of organic geochemical and isotopic characterization of organic matter in this clay unit. The age model, based on 14C data, showed that the clay was deposited during a period about from 11,100 to 7500 cal. years BP. Hydrogen Index values lower than 100 mgHC/gTOC, n-alkane distributions with maxima at nC29 or at nC31, a predominance of long-chain n-alkanes (C25–C33) and δ13Corg values around −24‰ to −27‰ suggest a predominantly terrestrial origin of organic matter from C3 plants. Obvious excursions of bulk δ13Corg and compound-specific δ13C and δD values of nC27, nC29, nC31, and nC33 are interpreted as indicators of changes in environmental and climatic conditions. Several shifts toward colder and warmer climatic conditions were identified and dated. Furthermore, two sudden changes in the hydrological regime were dated to 9000–8820 cal. years BP and to 8150–8050 cal. years BP toward wetter and drier conditions, respectively. Specific molecular organic geochemical indicators such as faecal sterols or a strong enrichment of δ15N caused by human impact could not be detected. Therefore, the swamp should not have been intensively affected by Neolithic people and/or respective indicators of their influence have been diluted due to the high sedimentation rate.

scholarly journals A Metacommunity Approach to Improve Biological Assessments in Highly Dynamic Freshwater Ecosystems

BioScience ◽  
2020 ◽  
Vol 70 (5) ◽  
pp. 427-438 ◽  
Author(s):  
Núria Cid ◽  
Núria Bonada ◽  
Jani Heino ◽  
Miguel Cañedo-Argüelles ◽  
Julie Crabot ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Environmental Variability ◽  
Anthropogenic Impacts ◽  
Dispersal Limitation ◽  
Freshwater Ecosystems ◽  
Metacommunity Ecology ◽  
Intermittent Rivers ◽  
Biological Assessments ◽  
Quality Assessments ◽  
Flow Intermittence

Abstract Rapid shifts in biotic communities due to environmental variability challenge the detection of anthropogenic impacts by current biomonitoring programs. Metacommunity ecology has the potential to inform such programs, because it combines dispersal processes with niche-based approaches and recognizes variability in community composition. Using intermittent rivers—prevalent and highly dynamic ecosystems that sometimes dry—we develop a conceptual model to illustrate how dispersal limitation and flow intermittence influence the performance of biological indices. We produce a methodological framework integrating physical- and organismal-based dispersal measurements into predictive modeling, to inform development of dynamic ecological quality assessments. Such metacommunity-based approaches could be extended to other ecosystems and are required to underpin our capacity to monitor and protect ecosystems threatened under future environmental changes.

Molecular and isotopic characterization of the particulate organic matter from an eutrophic coastal bay in SE Brazil

2009 ◽  
Vol 29 (19) ◽  
pp. 2293-2302 ◽  
Author(s):  
Francine A. Kalas ◽  
Renato S. Carreira ◽  
Stephen A. Macko ◽  
Angela L. R. Wagener
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Se Brazil ◽  
Isotopic Characterization ◽  
Coastal Bay

Molecular and isotopic characterization of organic matter in recent and sub-recent sediments from the Dead Sea

2000 ◽  
Vol 31 (4) ◽  
pp. 251-265 ◽  
Author(s):  
Thomas B.P Oldenburg ◽  
Jürgen Rullkötter ◽  
Michael E Böttcher ◽  
Arie Nissenbaum
Keyword(s):  
Organic Matter ◽  
Dead Sea ◽  
Isotopic Characterization ◽  
The Dead ◽  
Recent Sediments

Sources of 137Cs fluvial export from a forest catchment evaluated by stable carbon and nitrogen isotopic characterization of organic matter

2017 ◽  
Vol 314 (1) ◽  
pp. 403-411 ◽  
Author(s):  
Kotomi Muto ◽  
Mariko Atarashi-Andoh ◽  
Jun Koarashi ◽  
Erina Takeuchi ◽  
Syusaku Nishimura ◽  
...  
Keyword(s):  
Organic Matter ◽  
Stable Carbon ◽  
Carbon And Nitrogen ◽  
Forest Catchment ◽  
Isotopic Characterization

scholarly journals Geochemical characterization of clastic sediments sheds light on energy sources and on alleged anthropogenic impacts in cave ecosystems

2022 ◽  
Author(s):  
Rosangela Addesso ◽  
Jo De Waele ◽  
Simona Cafaro ◽  
Daniela Baldantoni
Keyword(s):  
Organic Matter ◽  
Energy Input ◽  
Anthropogenic Impacts ◽  
Limiting Factor ◽  
Ecological Processes ◽  
Clastic Sediments ◽  
Main Host ◽  
Cave Ecosystems ◽  
Oligotrophic Ecosystems

AbstractCaves are usually oligotrophic ecosystems, where the organic matter represents a limiting factor to the hypogeal community and sediments are often a significant energy source. With a view to identifying the energy input influencing the ecological processes occurring in caves, as well as the potential alteration sources of the natural equilibriums, geochemical features of several typologies of clastic sediments from the Pertosa-Auletta Cave (Italy) were investigated. The collected sediments, analyzed for a number of chemical (organic matter, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, Ti, V, Zn concentrations) and mineralogical (quartz, calcite, dolomite, clay minerals) characteristics, showed a different composition. Overall, their origin is supposed to be allochthonous, related to the important fluviokarst activities interesting the cave in the past, whereas the abundance of calcitic and dolomitic compounds can be autochthonous, being the carbonate the main host rock. The highest concentrations of organic matter, together with C, Cu, Mo, N, P, Pb, S and Zn, highlighted in one sample composed mainly of bats guano, revealed an important bioavailable energy input as well as a pollutant accumulation, mainly of anthropogenic origin.

scholarly journals Towards Organic Carbon Isotope Records from Stalagmites: Coupled δ13C and 14C Analysis Using Wet Chemical Oxidation

Radiocarbon ◽  
2019 ◽  
Vol 61 (03) ◽  
pp. 749-764
Author(s):  
Franziska A Lechleitner ◽  
Susan Q Lang ◽  
Negar Haghipour ◽  
Cameron McIntyre ◽  
James U L Baldini ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Isotope ◽  
Method Development ◽  
Chemical Oxidation ◽  
Low Concentrations ◽  
Crucial Information ◽  
Isotopic Characterization ◽  
Wet Chemical

AbstractSpeleothem organic matter can be a powerful tracer for past environmental conditions and karst processes. Carbon isotope measurements (δ13C and 14C) in particular can provide crucial information on the provenance and age of speleothem organic matter, but are challenging due to low concentrations of organic matter in stalagmites. Here, we present a method development study on extraction and isotopic characterization of speleothem organic matter using a rapid procedure with low laboratory contamination risk. An extensive blank assessment allowed us to quantify possible sources of contamination through the entire method. Although blank contamination is consistently low (1.7 ± 0.34 – 4.3 ± 0.86 μg C for the entire procedure), incomplete sample decarbonation poses a still unresolved problem of the method, but can be detected when considering both δ13C and 14C values. We test the method on five stalagmites, showing reproducible results on samples as small as 7 μg C for δ13C and 20 μg C for 14C. Furthermore, we find consistently lower non-purgeable organic carbon (NPOC) 14C values compared to the carbonate 14C over the bomb spike interval in two stalagmites from Yok Balum Cave, Belize, suggesting overprint of a pre-aged or even fossil source of carbon on the organic fraction incorporated by these stalagmites.

Decadal high-resolution multi-proxy analysis to reconstruct natural and human-induced environmental changes over the last 1350 cal. yr BP in the Altai Tavan Bogd National Park, western Mongolia

The Holocene ◽  
2020 ◽  
Vol 30 (7) ◽  
pp. 1016-1028 ◽  
Author(s):  
Julia Unkelbach ◽  
Kaoru Kashima ◽  
Gaadan Punsalpaamuu ◽  
Lyudmila Shumilovskikh ◽  
Hermann Behling
Keyword(s):  
High Resolution ◽  
Water Availability ◽  
National Park ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Climatic Conditions ◽  
Forest Steppe ◽  
Permafrost Degradation ◽  
Rainfall Events ◽  
The Impact

The ‘Altai Tavan Bogd’ National Park in the north-western part of the Mongolian Altai, Central Asia, is located in a forest-steppe ecosystem. It occurs under the influence of extreme continental and montane climate and is sensitive to natural and anthropogenic impacts. High-resolution (<20 years per sample) multi-proxy data of pollen, non-pollen palynomorphs (NPPs), macro-charcoal, diatoms, and XRF scanning from radiocarbon-dated lacustrine sediments reveal various environmental changes and the impact of different settlement periods for the late-Holocene. From 1350 to 820 cal. yr BP (AD 600–1130), the distribution of grass steppe indicates a climate similar to present-day conditions. Rapid improvements of climatic conditions (e.g. increased rainfall events) possibly favored a recovery of forest-steppe encouraging nomadic movements into alpine areas. In the period from 820 to 400 cal. yr BP (AD 1130–1550), the decline of forested areas suggests an increasingly drier and possibly colder climate. Some political shifts during the Mongol Empire (744–582 cal. yr BP; AD 1206–1368) favored variations in nomadic grazing habits. After 400 cal. yr BP (AD 1550), moisture and temperature increased slightly, and from ca. 40 cal. yr BP (AD 1910) to present, annual temperature continued to increase more markedly favoring an additional water availability due to permafrost degradation. Diatom data suggest several intervals of increased water availability in all periods which might have caused erosion due to heavier rainfall events or increased snow melt. Immediately after most of these high-water intervals, NPP data reveal periods of increased grazing activities in the area.

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