Three-year decline of magmatic CO2emissions from soils of a Mammoth Mountain Tree Kill: Horseshoe Lake, CA, 1995-1997

Skousen and Aiuvalasit critique our article on the post-Mississippian occupation of the Horseshoe Lake watershed (White et al. 2020) along two lines: (1) that our findings are not supported due to a lack of archaeological evidence, and (2) that we do not consider alternative hypotheses in explaining the lake's fecal stanol record. We first respond to the matter of fecal stanol deposition in Horseshoe Lake and then address the larger issue, the primacy of archaeological data in interpreting the past.

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Long-term year-round observations of magmatic CO2 emissions on Mammoth Mountain, California, USA

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2021.107347 ◽

2021 ◽

pp. 107347

Author(s):

J.L. Lewicki

Keyword(s):

Co2 Emissions ◽

Mammoth Mountain

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Bridge River tephra: revised distribution and significance for detecting old carbon errors in radiocarbon dates of limnic sediments in southern British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e80-153 ◽

1980 ◽

Vol 17 (11) ◽

pp. 1454-1461 ◽

Cited By ~ 39

Author(s):

Rolf W. Mathewes ◽

John A. Westgate

Keyword(s):

British Columbia ◽

Sedimentary Rocks ◽

Lacustrine Sediments ◽

Igneous Rocks ◽

The South ◽

Radiocarbon Dates ◽

Carbon Contamination ◽

Horseshoe Lake ◽

Tephra Beds

Ash-grade Bridge River tephra, identified as such on the basis of shard habit, modal mineralogy, and composition of ilmenite, occurs in sedimentary cores from three lakes located to the south of the previously documented plume and necessitates a significant enlargement of the fallout area of that tephra in southwestern British Columbia.These new, more southerly occurrences are probably equivalent to the ~2350 year old Bridge River tephra, although it can be argued from the evidence at hand that the 14C dates and biotite-rich nature support relationship to a slightly earlier Bridge River event.Large differences exist in the 14C age of sediments immediately adjacent to the Bridge River tephra at these three lake sites; maximum ages of 3950 ± 170 years BP (GX-5549) and 3750 ± 210 years BP (I-10041) were obtained at Phair and Fishblue lakes, respectively, whereas the corresponding age at Horseshoe Lake is only 2685 ± 180 years BP (GX-5757). The two older dates are considered to be significantly affected by old carbon contamination for the bedrock locally consists of calcareous sedimentary rocks and the lacustrine sediments are very calcareous. The 14C date from Horseshoe Lake, which occurs in an area of igneous rocks, appears to be only slightly too old relative to the ~2350 year old Bridge River tephra.Well-dated tephra beds, therefore, can be very useful in assessing the magnitude of old carbon errors associated with radiocarbon dates based on limnic sediments. Calcareous gyttja deposits beneath Bridge River tephra within the study area exhibit old carbon errors of the order of 1350–1550 years.

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Monitoring natural analog of Geologic Carbon Sequestration using multi-temporal Landsat TM images in Mammoth Mountain, long valley cadera, California

2011 IEEE International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.2011.6050182 ◽

2011 ◽

Cited By ~ 1

Author(s):

Rattanasuda Cholathat ◽

Xiaojing Li ◽

Linlin Ge

Keyword(s):

Carbon Sequestration ◽

Landsat Tm ◽

Geologic Carbon Sequestration ◽

Mammoth Mountain ◽

Natural Analog ◽

Long Valley ◽

Multi Temporal

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Ecosystem responses to elevated CO<sub>2</sub> using airborne remote sensing at Mammoth Mountain, California

Biogeosciences ◽

10.5194/bg-15-7403-2018 ◽

2018 ◽

Vol 15 (24) ◽

pp. 7403-7418 ◽

Cited By ~ 3

Author(s):

Kerry Cawse-Nicholson ◽

Joshua B. Fisher ◽

Caroline A. Famiglietti ◽

Amy Braverman ◽

Florian M. Schwandner ◽

...

Keyword(s):

Remote Sensing ◽

Co2 Emissions ◽

Elevated Co2 ◽

Co2 Flux ◽

Ecosystem Structure ◽

Soil Co2 ◽

Ecosystem Responses ◽

Mammoth Mountain ◽

And Function ◽

Canopy Nitrogen

Abstract. We present an exploratory study examining the use of airborne remote-sensing observations to detect ecological responses to elevated CO2 emissions from active volcanic systems. To evaluate these ecosystem responses, existing spectroscopic, thermal, and lidar data acquired over forest ecosystems on Mammoth Mountain volcano, California, were exploited, along with in situ measurements of persistent volcanic soil CO2 fluxes. The elevated CO2 response was used to statistically model ecosystem structure, composition, and function, evaluated via data products including biomass, plant foliar traits and vegetation indices, and evapotranspiration (ET). Using regression ensemble models, we found that soil CO2 flux was a significant predictor for ecological variables, including canopy greenness (normalized vegetation difference index, NDVI), canopy nitrogen, ET, and biomass. With increasing CO2, we found a decrease in ET and an increase in canopy nitrogen, both consistent with theory, suggesting more water- and nutrient-use-efficient canopies. However, we also observed a decrease in NDVI with increasing CO2 (a mean NDVI of 0.27 at 200 g m−2 d−1 CO2 reduced to a mean NDVI of 0.10 at 800 g m−2 d−1 CO2). This is inconsistent with theory though consistent with increased efficiency of fewer leaves. We found a decrease in above-ground biomass with increasing CO2, also inconsistent with theory, but we did also find a decrease in biomass variance, pointing to a long-term homogenization of structure with elevated CO2. Additionally, the relationships between ecological variables changed with elevated CO2, suggesting a shift in coupling/decoupling among ecosystem structure, composition, and function synergies. For example, ET and biomass were significantly correlated for areas without elevated CO2 flux but decoupled with elevated CO2 flux. This study demonstrates that (a) volcanic systems show great potential as a means to study the properties of ecosystems and their responses to elevated CO2 emissions and (b) these ecosystem responses are measurable using a suite of airborne remotely sensed data.

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