Seasonal effects of water temperature and dissolved oxygen on the isoGDGT proxy (TEX86) in a Mediterranean oligotrophic lake

Cao, Min; Rivas-Ruiz, Pedro; Trapote, Maria del Carmen; Vegas‐Vilarrúbia, Teresa; Rull, Valentı́; Rosell‐Melé, Antoni

doi:10.1016/j.chemgeo.2020.119759

Cited by 18 publications

(11 citation statements)

References 63 publications

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“…Significant correlations were found between TEX 86 and DO (R 2 = 0.14, p < 0.01) and pH (R 2 = 0.36, p < 0.01), indicating that TEX 86 does not only serve temperature in the ECS during summer. Samples with temperatures below 25.0 • C have relatively low DO content and pH values driven by stratification, and TEX 86 increased compared to the relational equation for samples with a temperature greater than 25.0 • C. This phenomenon was consistent with previous findings, indicating that a decrease in DO or pH could lead to an increase in TEX 86 (Elling et al, 2015;Zhang et al, 2016;Lü et al, 2019a;Cao et al, 2020). For samples with a temperature below 25.0 • C, a significant correlation was found between pH and TEX 86 (R 2 = 0.33, p < 0.05), but no significant correlation was found between DO and TEX 86 , indicating that the effect of pH on TEX 86 was greater than that of DO.…”

Section: Re-evaluating the Records And Robustness Of Tex 86supporting

confidence: 89%

Variation of Isoprenoid GDGTs in the Stratified Marine Water Column: Implications for GDGT-Based TEX86 Paleothermometry

et al. 2021

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Isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) derived from archaea are lipid biomarkers that exhibit high sensitivity to changes in water temperature, leading to the widespread application of the isoGDGT-based tetraether index of 86 carbon atoms (TEX86) in surface seawater temperature (SST) reconstruction. However, there remain some uncertainties regarding the robustness of TEX86 under changing water conditions (e.g., variations in water depth, oxygen and pH). Here, we analyzed isoGDGTs in suspended particles at different depths of the East China Sea (ECS) during summer 2020, aiming to constrain the applicability of the TEX86 proxy in coastal waters. Our data showed that the isoGDGTs were mainly derived from planktonic Thaumarchaeota, as revealed by the low ratio of GDGT-0/crenarchaeol (<0.5). The vertical distribution of isoGDGT concentration depicted a downward increase from the surface to the bottom. This observation was likely shaped by Thaumarchaeota, which regulate the extent of ammonia oxidation based on the availability of ammonium. The occurrence of maximal isoGDGT concentrations in the bottom layer suggests that the isoGDGTs in sediments are mainly controlled by bottom archaeal production rather than surface archaeal production. By reanalyzing the published isoGDGT data of surface sediments in the ECS inner shelf, we found that the sedimentary TEX86 relates much better to the annual mean bottom seawater temperature (BST) than to the annual mean SST, indicating that sedimentary TEX86 is more inclined to be a proxy for the BST in the shallow ECS. In addition, the positive bias of TEX86 driven by low dissolved oxygen and low pH was observed under the pycnocline, indicating that the application of TEX86 to reconstruct seawater temperature should be carefully appraised in coastal environments with strong water column stratification.

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Section: Re-evaluating the Records And Robustness Of Tex 86supporting

confidence: 89%

Variation of Isoprenoid GDGTs in the Stratified Marine Water Column: Implications for GDGT-Based TEX86 Paleothermometry

et al. 2021

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“…DO reflects the oxygen content in the water body. An important indicator to measure the self-purification ability of water bodies (Cao et al 2020).…”

Section: Water Qualitymentioning

confidence: 99%

Ecosystem Health of the Beiyun River Basin (Beijing, China) as Evaluated by the Analytic Hierarchy Process Method

Yuan

Zhao

et al. 2021

Preprint

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Ecosystem services provided by river ecosystems rely on healthy ecosystem structure and ecological processes. The Beijing-Tianjin-Hebei urban is a typical water-deficient area. As an important part of the urban-rural integration construction, evaluating the health status of the Beiyun River Basin and discovering the weak links in the water environment is the basis for improving the health of the basin. In this study, Analytic Hierarchy Process was used to establish an evaluation index system for the Beiyun River Basin from 5 aspects including water quality, biology, habitat, hydrology, and social functions, and to assign weights to the index layer. The evaluation results showed that the health evaluation results of the Beiyun River Basin in 2019 are “sub-healthy”, and the overall health status is gradually worsening from northwest to southeast. In the middle reaches of the region, the evaluation result is "healthy", followed by the upstream, and the downstream is the worst. The results showed that areas with less human interference are in better health. The factors that affect the overall health evaluation status in the basin are the level of nutrition, biodiversity, and vegetation coverage. For the comprehensive management of the Beiyun River, the improvement of water quality and habitat ecological restoration is the key to the health of the upstream ecosystem health status. The improvement of the health status of the downstream should focus on equal emphasis on water quality and quantity, restoration of biodiversity, and improvement of the quality of the riparian ecological environment.

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“…During the last decade, these unique sediments have been intensively studied and have provided high-resolution paleoclimatic and paleoecological records that can be considered as a reference for the western Mediterranean region. These studies include, among others, varve formation and chronology, sediment yield history, past temperature and precipitation reconstructions (including heavy rainfall events), hypoxia and oxygenation events in lake waters, paleolimnological reconstructions (diatoms, pigments and other algae remains), vegetation and landscape dynamics, anthropization timing and patterns, human-impact history (burning, deforestation, cultivation, grazing), comparisons between paleoecological and historical records, and modern-analog studies for paleoclimatic and paleoecological reconstruction using physico-chemical and biological proxies, including biomolecular markers (Cao et al, 2020;Corella et al, 2011Corella et al, , 2012Corella et al, , 2014Corella et al, , 2016Corella et al, , 2019Montoya et al, 2018;Rull and Vegas-Vilarrúbia, 2014Rull et al, 2011Rull et al, , 2017Rull et al, , 2021aScussolini et al, 2011;Trapote et al, 2018a, b;Vegas-Vilarrúbia et al, 2018.…”

Section: Introductionmentioning

confidence: 99%

“…Trapote et al (2018) used short-term (~2 years) temperature series measured in lake waters to study the formation of modern varves in terms of climatic seasonality, and to extrapolate these relationships to the past. The same short-term climatic data were used to assess the responses of present-day photosynthetic algae to environmental drivers, as a tool for paleoclimatic inference using the same proxies preserved in lake sediments (Vegas-Vilarrúbia et al, 2020). Cao et al (2020) used similar shortterm climatic data to calibrate molecular biomarkers (GDGTs) in terms of temperature, to obtain a molecular paleothermometer.…”

Section: Introductionmentioning

confidence: 99%

“…The same short-term climatic data were used to assess the responses of present-day photosynthetic algae to environmental drivers, as a tool for paleoclimatic inference using the same proxies preserved in lake sediments (Vegas-Vilarrúbia et al, 2020). Cao et al (2020) used similar shortterm climatic data to calibrate molecular biomarkers (GDGTs) in terms of temperature, to obtain a molecular paleothermometer.…”

Section: Introductionmentioning

confidence: 99%

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Present climate of lake Montcortès (Central Pyrenees): paleoclimatic relevance and insights on future warming

Rull

Sigrò²,

Vegas-Vilarrúbia³

2022

CIG

Self Cite

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The varved sediments of the Pyrenean Lake Montcortès (Pallars Sobirà, Lleida) embody a unique continuous high-resolution (annual) paleoarchive of the last 3000 years for the circum-Mediterranean region. A variety of paleoclimatic and paleoecological records have been retrieved from these uncommon sediments that have turned the lake into a regional reference. Present-day geographical, geological, ecological and limnological features of the lake and its surroundings are reasonably well known but the lack of a local weather station has prevented characterization of current climate, which is important to develop modern-analog studies for paleoclimatic reconstruction and to forecast the potential impacts of future global warming. Here, the local climate of the Montcortès area for the period 1955-2020 is characterized using a network of nearby stations situated along an elevational transect in the same river basin of the lake. The finding of statistically significant elevational gradients for average temperature and precipitation (-0.59 °C and 82 mm per 100 m elevation, respectively) has enabled to estimate these parameters and their seasonal regime for the lake site. The estimated average annual temperature is 9.7±0.8 °C and the estimated total annual precipitation is 1031±34 mm, in average. A representative climograph has been shaped with these data that can serve as a synthetic descriptive and comparative climatic tool. The same analysis has provided climatic data for modern-analog studies useful to improve the interpretation of sedimentary records in climatic and ecological terms. In addition, the seasonal slope shifting of the climatic elevational gradients has been useful to gain insights about possible future climatic trends under a warming scenario

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Seasonal effects of water temperature and dissolved oxygen on the isoGDGT proxy (TEX86) in a Mediterranean oligotrophic lake

Cited by 18 publications

References 63 publications

Variation of Isoprenoid GDGTs in the Stratified Marine Water Column: Implications for GDGT-Based TEX86 Paleothermometry

Variation of Isoprenoid GDGTs in the Stratified Marine Water Column: Implications for GDGT-Based TEX86 Paleothermometry

Ecosystem Health of the Beiyun River Basin (Beijing, China) as Evaluated by the Analytic Hierarchy Process Method

Present climate of lake Montcortès (Central Pyrenees): paleoclimatic relevance and insights on future warming

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