Three Millennia of Vegetation, Land-Use and Climate Change in SE Sicily

This study presents the first Late Holocene marine pollen record (core ND2) from SE Sicily. It encompasses the last 3000 years and is one of the most detailed records of the south-central Mediterranean region in terms of time resolution. The combined approach of marine palynology and historical ecology, supported by independent palaeoclimate proxies, provides an integrated regional reconstruction of past vegetational dynamics in relation to rapid climatic fluctuations, historical socio-economic processes, and past land-use practices, offering new insights into the vegetation history of SE Sicily. Short-term variations of sparse tree cover in persistently open landscapes reflect rapid hydroclimatic changes and historical land-use practices. Four main phases of forest reduction are found in relation to the 2.8 ka BP event, including the Late Antique Little Ice Age, the Medieval Climate Anomaly, and the Little Ice Age, respectively. Forest recovery is recorded during the Hellenistic and Roman Republican Periods, the Early Middle Ages, and the last century. Agricultural and silvicultural practices, as well as stock-breeding activities, had a primary role in shaping the current vegetational landscape of SE Sicily.

Economics and politics of “old confrontation” in the New Arctic

The modern Arctic is becoming the strategic space and area of competition of many powers, the arena of political confrontations between Arctic and non-Arctic states. Arctic research has moved from the sphere of science to the sphere of geopolitics and geoeconomics and is of strategic importance in the system of national security. Climatic fluctuations in the Arctic have increased the availability of hydrocarbon, biological and other resources, and improved ice conditions in the water area of the Northern Sea Route. The study analyzes the Arctic policy of Western European and North American countries in the conditions of the “New Arctic”. An overview of strategic documents on ensuring the spatial development.

Role of Polyamines in Regulating Abiotic Stress Tolerance in Agricultural Crops: A Review

At present plants had to face adverse climatic fluctuations which are often detrimental for their growth in order to cope up with this situation, they develop certain adaptive tactics like synthesis of new proteins, micro RNAs, compatible solutes/ osmolites and radical release to avoid its adverse effects. Of these study on compatible solutes such as polyamines (PAs) gained popularity among researchers. In plant, they are involved in a wide variety of regulatory and cellular processes under normal conditions. During these stresses they acts by activating biosynthesis of signaling molecules like NO, H2O2; affects abscisic acid synthesis; Ca2+ homeostasis; ion channel signaling or even apoptosis in severe conditions. Over expression of PAs is reported in various stresses due to the presence of stress-responsive elements in the promoters of PA biosynthetic genes. This review paper, summarizes the effect of polyamines in boosting plants growth during abiotic stress and its mechanisms of action.

The Effects of Climatic Variability on the Feeding Ecology of the Scalloped Hammerhead Shark (Sphyrna lewini) in the Tropical Eastern Pacific

Climatic variability changes ocean productivity and generates systematic cascading effects in marine food webs. Studying the feeding ecology of top predators, such as sharks, can provide insights into the overall health of marine ecosystems. We conducted a 4-year study to evaluate seasonal and inter-annual trophic variations and their relationship with El Niño Southern Oscillation (ENSO) on the largest aggregation of scalloped hammerhead shark (Sphyrna lewini) in the Tropical Eastern Pacific (TEP). We used δ13C and δ15N signatures to gain a better understanding of hammerheads’ feeding strategies as well as variations of their isotopic niche. Our results suggest that the hammerhead sharks in the Galapagos Marine Reserve respond to climatic fluctuations, with La Niña event potentially benefiting their trophic needs as the overall marine productivity increased in the region. This work is the first of its kind in the TEP and provides insights on how climate variability influences the feeding ecology of this critically endangered species. It also highlights the need to incorporate climate-related conservation strategies into the management of this species since ENSO events become more frequent and intense in the face of climate change.

Greenhouse gas emission fluxes from peat bogs in the Arak Lake Basin in 2021

Climate change has an important impact on greenhouse gas emissions from wetland ecosystems. The static box-meteorological chromatography method was used to determine the CO2 and CH4 emission fluxes of hummocky and hollow in the peat bogs in the Arak Lake Basin during the growing season in 2021. The results showed that the peaks of the CO2 and CH4 emission fluxes in the growing seasons of the hummocky and hollow appeared in July, and their value in May is the lowest. The average C02 emission flux (376.39±56.14 mg-m-2-h-1) during the growing season of hummocky is higher than that of hollow (167.36 mg-m-2-h-1), while the average emission flux of CH4 during the growing season of hummocky (2.00±0.31 mg-m-2-h-1) is lower than that of hollow (3.04 mg-m-2-h-1). The climatic fluctuations have caused differences in the CO2 and CH4 emission fluxes of the same micro-topography in the study area during the growing season between 2020 and 2021.

Chronology of sedimentation in Colesbukta, Spitsbergen (Svalbard Archipelago): the results of the 2018 expedition

This paper presents results of a study of sedimentation in Colesbukta (Isfjorden, Spitsbergen), a typical example of sedimentation in a shallow bay of the Svalbard Archipelago. We have examined sediment samples from several cores collected in Colesbukta in May 2018. To meet the goals of this study, geomorphological features of the Colesbukta catchment area have been identified and described. The lithological characteristics of bottom sediments from the study area have been described and their spatial and temporal changes analyzed. The chronology of sedimentation has been reconstructed by 210Pb and 137Cs. We have calculated sedimentation rates in Colesbukta and their temporal dynamics over the several latest decades. According to our estimations, the sedimentation rate has increased by 2–4 times compared to the middle of the 20th century and ranges from 0.2 to 0.46 mm/year depending on the individual conditions of sedimentation in each part of the bay. Climatic fluctuations are shown to have a direct impact on sedimentation processes in Colesbukta. We have revealed that on the periphery of the studied area the rate of sedimentation better depends on the temperature regime while in its central part it is rather a result of the amount of atmospheric precipitation.

The Stalagmite Record of Southern Arabia: Climatic Extremes, Human Evolution and Societal Development

The fluctuating climatic conditions of the Saharo-Arabian deserts are increasingly linked to human evolutionary events and societal developments. On orbital timescales, the African and Indian Summer Monsoons were displaced northward and increased precipitation to the Arabian Peninsula which led to favorable periods for human occupation in the now arid interior. At least four periods of climatic optima occurred within the last 130,000 years, related to Marine Isotope Stages (MIS) 5e (128–121 ka BP), 5c (104–97 ka BP), 5a (81–74 ka BP) and 1 (10.5–6.2 ka BP), and potentially early MIS 3 (60–50 ka BP). Stalagmites from Southern Arabia have been key to understanding climatic fluctuations and human-environmental interactions; their precise and high-resolution chronologies can be linked to evidence for changes in human distribution and climate/environment induced societal developments. Here, we review the most recent advances in the Southern Arabian Late Pleistocene and Early Holocene stalagmite records. We compare and contrast MIS 5e and Early Holocene climates to understand how these differed, benchmark the extremes of climatic variability and summarize the impacts on human societal development. We suggest that, while the extreme of MIS 5e was important for H. sapeins dispersal, subsequent, less intense, wet phases mitigate against a simplistic narrative. We highlight that while climate can be a limiting and important factor, there is also the potential of human adaptability and resilience. Further studies will be needed to understand spatio-temporal difference in human-environment interactions in a climatically variable region.

Evidence of Mid-Holocene (Northgrippian Age) Dry Climate Recorded in Organic Soil Profiles in the Central Appalachian Mountains of the Eastern United States

Peatlands in Canaan Valley National Wildlife Refuge hold a pedomemory of Pleistocene and Holocene climatic fluctuations in the central Appalachian Mountains of the eastern United States. A field investigation profiling 88 organic soil profiles, coupled with 52 radiocarbon dates and peat accumulation rates, revealed a distinct sequence of organic soil horizons throughout five study areas. The dominantly anaerobic lower portions of the organic soil profiles consist of varied thicknesses of hemic and sapric soil materials, typically layered as an upper hemic horizon, underlain by a sapric horizon, underlain by another hemic horizon. Peat deposition began after the Last Glacial Maximum with relatively high Heinrich Stadial 1 accumulation rates to form the lowest hemic horizon. Peat accumulated at significantly slower rates as the climate continued to warm in the early Holocene Greenlandian Age. However, between 10,000 and 4200 cal yr BP peat accumulation decreased further and the decomposition of previously deposited peat prevailed, forming the sapric horizon. This interval of greater decomposition indicates a drier climatic with dates spanning the late Greenlandian Age through the Northgrippian Age. The upper hemic horizon within the anaerobic portion of the soil profile formed from high peat accumulation rates during the wetter late Holocene Meghalayan Age.