scholarly journals A high-resolution environmental change record since 19 cal ka BP in Pumoyum Co, southern Tibet

2011 ◽  
Vol 56 (27) ◽  
pp. 2931-2940 ◽  
Author(s):  
XinMiao Lü ◽  
LiPing Zhu ◽  
Mitsugu Nishimura ◽  
Yoshimune Morita ◽  
Takahiro Watanabe ◽  
...  
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
Southern Tibet ◽  
Pumoyum Co

Shelf ecosystem response to the Eocene-Oligocene Transition

2020 ◽  
Author(s):  
Laura Cotton ◽  
David Evans ◽  
Daniela Schmidt
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
Trace Element ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Open Ocean ◽  
Ecosystem Dynamics ◽  
Ecosystem Response ◽  
Holistic View ◽  
Shallow Marine

<p>The Eocene-Oligocene transition (EOT) is one of the most dramatic climate shifts of the Cenozoic with severe consequences for reef ecosystems. The onset of continental Antarctic glaciation is associated with widespread environmental change, resulting in a global peak in biotic turnover. Whilst numerous studies of the biotic response to the changes at the EOT have been carried out, most high-resolution studies consist of open ocean records of marine plankton and predominantly single groups of organisms. However, this is not representative of the ocean system as a whole and does not provide a holistic view of mechanism of restructuring of the marine ecosystems. The shelf seas and reefs are some of the most diverse and fundamentally important ecosystems of the oceans. Long-term diversity loss across the EOT has been shown in several macrofossil studies, but mainly at low resolution, and recovery is not well understood.  Many shelf species are ecosystem engineers whose loss and recovery have profound implications for the entire ecosystem. Understanding these interactions will provide insights into shallow marine ecosystems and their response to major climate perturbations.</p><p>The Tanzanian Drilling Project EOT record (TDP 11, 12, 17) is recognised globally for its completeness and exceptionally preserved calcareous microfossils. It is most importantly, though, a rare record of both shallow water organisms and open ocean plankton. The latter are fundamentally important for reconstructions of the environment and a globally calibrated timescale. Here we draw together a unique dataset of high-resolution mollusc, Dasycladaceae, bryozoan, larger benthic foraminifers, coral, smaller benthic foraminifera, trace element and isotope records from the EOT. The response and recovery of these species is compared with known, modern physiology of each group to provide a complete picture of the shallow marine ecosystem response.</p><p>Following rapid extinctions within the larger foraminifera during the transition, molluscs, Dasycladaceae and bryozoans all show increases in abundance, indicating a major shift in shelf ecosystem composition. These assemblage changes are coincident with a period of more positive values in d<sup>13</sup>C of both benthic and planktonic foraminifera and changes in trace element values. Comparison with the open ocean record of planktonic foraminiferal, pteropod, and nannofossils confirm these assemblage changes are a biological, rather than sedimentological response and additionally support a that a transition to more eutrophic conditions took place. an environmental framework of traditional and novel geochemistry, indicate that increased nutrient fluxes played a pivotal role in restructuring shelf ecosystem dynamics and therefore offers new insight into mechanisms of reorganisation under ecosystem loss and environmental change.</p>

Late Holocene glacier and climate reconstruction from proglacial records in Vatnsdalur, northern Iceland.

2020 ◽  
Author(s):  
Konstantin Nebel ◽  
Timothy Lane ◽  
Kathryn Adamson ◽  
Iestyn Barr ◽  
Willem van der Bilt ◽  
...  
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
North Atlantic ◽  
Late Holocene ◽  
Sediment Cores ◽  
Arctic Region ◽  
Arctic Climate ◽  
The Arctic ◽  
Air Masses ◽  
Proglacial Lake

<p>The Arctic region is experiencing surface air temperature increase of twice the global average. To better understand Holocene Arctic climate variability, there is the need for continuous, high-resolution palaeoclimate archives. Sediment cores from proglacial lakes can provide such climate archives, and have the potential to record past environmental change in detail.       </p><p>Vatnsdalur, a valley in northern Iceland, hosts small, climatically sensitive cirque glaciers that became independent from the Iceland Ice Sheet after its retreat following the Last Glacial Maximum (c. 15 ka BP). Importantly, this region is located at the confluence of warm water and air masses from the south and cold polar water and air masses from the north, making it highly sensitive to North Atlantic and Arctic climate change. However, at present the region is highly understudied, lacking any high-resolution climate reconstructions.           </p><p>To address this, we combine geomorphological mapping with the first high-resolution analysis of proglacial lake sediments, to thoroughly examine northern Iceland Late Holocene environmental change.</p><p>Field mapping supplemented by high-resolution drone data was used to characterise catchment geomorphology, including seven Holocene moraines. A sediment core (SKD-P1-18) from proglacial lake Skeiðsvatn, Vatnsdalur, was analysed for sedimentological (dry bulk density, loss-on-ignition, grain size), geophysical (magnetic susceptibility) and geochemical (X-ray fluorescence core scan, 2 mm resolution) parameters.             <br>We identify three main sedimentary facies from these analyses, indicating variations in glacial input and catchment environmental conditions. Radiocarbon dating of lake macrofossils, supplemented by tephrochronology, provides a chronological framework. Catchment point samples, also analysed using the above analytical techniques, were used for sediment fingerprinting to disentangle non-glacial from glacial end-members.</p><p>Our results indicate the disappearance and reformation of small, climatically sensitive cirque glaciers in Vatnsdalur during the Holocene. We interpret the data to show an abrupt return to a glaciated catchment. Our results fill a geographical gap of high-resolution proglacial sediment studies in the Arctic-North Atlantic region.</p>

Change Detection Within Pipeline ROWs: Environmental Change Analysis Using High Resolution Satellite Imagery

2015 ◽  
Author(s):  
Otto Huisman ◽  
Arash Gharibi
Keyword(s):  
Decision Making ◽  
High Resolution ◽  
Environmental Change ◽  
Satellite Imagery ◽  
Vegetation Index ◽  
Low Cost ◽  
Comparison Method ◽  
Large Area ◽  
Change Analysis ◽  
High Resolution Satellite Images

One of the major concerns for pipeline operators is to efficiently monitor the events happening over the pipeline corridor, or right-of-way (ROW). Monitoring of the ROW is an important part of ensuring the safe and efficient transportation of oil and gas. Events occurring within this zone require rapid assessment and, if necessary, mitigation. These events could be physical intrusions such as encroachment from growing settlements, impact of vegetation, pipeline leakage or geo-environmental hazards. Analysis of satellite imagery can provide an efficient and low cost solution to access and quantify change across the ROW. Examining these events over a periodic interval requires implementation of specific methods that can support the on-going monitoring and decision making practices. In this context, satellite remote sensing images can provide a low cost and efficient solution for monitoring the physical and environmental impacts over the ROW of pipeline system. This paper reports on the development of a methodological approach for environmental change analysis using high resolution satellite images that can help decision making in pipeline systems. Analysis results and maps produced during this work provide an insight into landcover change over the study area and expected to support in on-going pipeline management practices. Two methods, Vegetation index differencing and post classification comparison have been implemented to identify change areas in the Taranaki region of the North Island of New Zealand. Vegetation index differencing with NDVI shows increase or decrease of overall vegetation within the study area. Special focus was given on large area increase and decrease with area threshold value above 0.2 hectare. Detailed analysis of change was conducted with post classification comparison method that uses land cover classification results of year 2010 and 2013. An overall change of 10% has been observed throughout the study area with large area change of approximately 5%. Results obtained from post classification comparison method were further analyzed with 6 focus areas and compared with the existing soil data and rainfall data. The methods adopted during this study are expected to provide a base for environmental change analysis in similar pipeline corridors to support decision making.

A high-resolution multi-proxy lake record of Holocene environmental change in southern Iceland

2015 ◽  
Vol 30 (3) ◽  
pp. 281-292 ◽  
Author(s):  
CELENE L. BLAIR ◽  
ÁSLAUG GEIRSDÓTTIR ◽  
GIFFORD H. MILLER
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
Lake Record ◽  
Holocene Environmental Change

Holocene environmental change inferred from a high-resolution pollen record, Lake Zhuyeze, arid China

The Holocene ◽  
2006 ◽  
Vol 16 (5) ◽  
pp. 675-684 ◽  
Author(s):  
Fa-Hu Chen ◽  
Bo Cheng ◽  
Yan Zhao ◽  
Yan Zhu ◽  
David B. Madsen
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
Pollen Record ◽  
Holocene Environmental Change

Technical Method to Study Climatic Environmental Change in Desert Region by Tamarix Cones

2012 ◽  
Vol 599 ◽  
pp. 888-893
Author(s):  
Hui Wang ◽  
Jia Zeng ◽  
Jing Zhang ◽  
Zeng Ying Sun ◽  
Yuan Jie Zhao
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
Theoretical Basis ◽  
Environmental Information ◽  
Desert Region ◽  
Environmental Sequence ◽  
The Past ◽  
Study Case ◽  
Lop Nor

Taking Lop Nor as a study case, the paper not only systematically discusses the dating of the Tamarix cone, the methods and technical routes to extract its climatic environmental information, but also interprets the environmental change in Lop Nor region in the past about one hundred and sixty years, which provides a new theoretical basis and technical reference for building the high-resolution environmental sequence in the relevant area.

Sign in / Sign up

Export Citation Format

Share Document