Evaluation of environmental proxies based on long chain alkyl diols in the East China Sea

He, Linghui; Kang, Manyu; Zhang, Dongrong; Jia, Guodong

doi:10.1016/j.orggeochem.2019.103948

Cited by 8 publications

(13 citation statements)

References 51 publications

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“…Again, C 30 1,15-diol was the major diol in this core (accounting for 65%-79% of total diols, average = 72%, n = 22) followed by C 32 1,15-diol (7%-12%, average = 9.4%, n = 22), C 28 1,14-diol (3.9%-15%, average = 8.9%, n = 22), C 30 1,14-diol (3.4%-7.1%, average = 5.2%, n = 22), and finally the 1,13-diols (1.4%-4.0%, average = 2.3% for C 30 1,13-diol; 0.4%-3.2%, average = 2.0% for C 28 1,13-diol, n = 22). Overall, the distribution of LCDs in the sediments from cores T06 and T08 shows that C 30 1,15-diol is the dominant component, 1,14-diols are the second most abundant, and 1,13-diols are present in the lowest proportions, which is consistent with what is known about the surface sediments of the ECS (He et al, 2020).…”

Section: Resultssupporting

confidence: 83%

“…The reason may be that the degradation of mono-unsaturated 1,14-diols is preference to saturated 1,14-diols (Rampen et al, 2014b). Moreover, previous study in the surface sediments of the ECS showed that nutrient diol index (NDI) based on 1,14-diols did not correlate well with nutrient concentrations, which may be related to the increase in silicate content due to nutrient input from freshwater such as the Yangtze River (He et al, 2020). This nutrient structure would hinder the growth of Proboscia diatoms which biosynthesize the 1,14-diols (Sinninghe Damsteé t al., 2003).…”

Section: Resultsmentioning

confidence: 95%

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Evolutions of upwelling and terrestrial organic matter input in the inner shelf of the East China Sea in the last millennium revealed by long-chain alkyl diols proxies

et al. 2022

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Long-chain alkyl diols (LCDs) can be used as organic geochemical proxies for paleoceanographic change, especially in marginal sea areas where large volumes of sediments are deposited rapidly and continuously. However, little is known about the applicability and response on a millennium scale in relation with existing records in those sediments. We reconstruct changes in upwelling and terrestrial organic matter (OM) input in core sediments from the Zhejiang Fujian coastal station (T08) and Yangtze River Estuary station (T06) in the inner shelf of the East China Sea (ECS) over the last millennium, using the LCD based proxies: diol index 2 (DI-2), and FC321,15-diol. Our results show that DI-2 values ([(C28+C30)1,14-diols]/([(C28+C30)1,13-diols]+[(C28+C30)1,14-diols])) at T08 decrease significantly during 600–400 yr BP but increase gradually after 400 yr BP. The FC321,15-diol proxy ([C321,15-diol]×100/([(C28+C30)1,13-diols]+[(C30+C32)1,15-diols])) at T06 shows marked fluctuations during 1000–800 yr BP, followed by a significant decline during 800–500 yr BP but a subsequent increase from 500 to 300 yr BP. We find that variations in DI-2 values are broadly consistent with changes in the strength of the East Asian Summer Monsoon (EASM) and the Kuroshio Current and are likely linked to changes in the frequency and intensity of the El Niño-Southern Oscillation (ENSO). The increased strength of the EASM causes greater offshore movement of the upper layer of seawater, which in turn triggers upwelling of bottom waters formed by Kuroshio subsurface waters. We find that variations in FC321,15-diol proxy are controlled mainly by the East Asian Winter Monsoon (EAWM) and the Yangtze River discharge. By increasing the strength of the EAWM, southward transportation of material deposited in the estuary of the Yangtze River by the ECS coastal currents is promoted. In addition, we synthesize records of other organic geochemical indicators nearby core sediments in the ECS; these records emphasize the importance of reconstructing the evolutionary history of upwelling and subdividing the relative inputs of terrestrial OM. Our study provides a new means for reconstructing the evolution of upwelling and terrestrial OM input in the inner shelf of the ECS over the last millennium.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 95%

Evolutions of upwelling and terrestrial organic matter input in the inner shelf of the East China Sea in the last millennium revealed by long-chain alkyl diols proxies

et al. 2022

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“…1 A and G ), which is consistent with earlier observations that the LDI temperature proxy shows the strongest correlation with summer SSTs ( 34 , 35 , 46 ). To explore this in more depth, we combined the surface sediment LCD datasets from a number of studies ( 34 , 47 – 49 ) to compare LCD distributions with mean annual, seasonal, and monthly values of temperature, nutrients, salinity, and mixed-layer depths ( Fig. 4 ) at a 1° and 0.25° grid resolution, obtained from the World Ocean Atlas 2018 ( 50 ).…”

Section: Resultsmentioning

confidence: 99%

The Long chain Diol Index: A marine palaeotemperature proxy based on eustigmatophyte lipids that records the warmest seasons

Rampen

Friedl

Rybalka

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Significance Organisms adjust their lipid compositions to environmental conditions like temperature. Some adaptations involve changes in ratios between unique lipids, which can still be determined after millions of years. Analyzing such lipid ratios in ancient sediments can be used for climate reconstruction. One example is the Long chain Diol Index (LDI). The lipids, produced by unknown biological sources, occur ubiquitously in marine sediments, and the LDI correlates with temperature. However, LDI records often differ from other temperature reconstructions. We now show that a clade of eustigmatophyte algae produces these lipids, providing information on their evolutionary history. We further demonstrate that the LDI registers temperatures of the warmest months instead of annual mean temperatures, which is valuable information for climate research.

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“…In river discharge regions (Iberian Atlantic, Berua delta, and CRE), FC 32 1,15‐diol correlated well with other riverine input proxies. For instance, there were strong correlations between the FC 32 1,15‐diol and other riverine input proxies in Iberian Atlantic ( R 2 = 0.77, Figure 7c; de Bar et al., 2016), Berua delta ( R 2 = 0.53, Figure 7i; Lattaud, Kim, et al., 2017), and CRE ( R 2 = 0.80, Figure 7j; He et al., 2020). However, in other regions, FC 32 1,15‐diol had weak correlations with BIT index.…”

Section: Discussionmentioning

confidence: 98%

“…We suggested that two main reasons for the differences between LDI‐SST in SPM and observed temperatures. First, a significant point affecting its deviation may be due to the terrestrial input, the LDI may be biased by freshwater‐derived LCDs, which can lead to significant bias in LDI‐SST (He et al., 2020). Especially in summer, the terrestrial input by CR could reach a yearly maximum (∼56,600 m 3 /s; Kong et al., 2004).…”

Section: Discussionmentioning

confidence: 99%

Seasonal Variation of Long‐Chain Alkyl Diols Proxies in Suspended Particulate Matter of the Changjiang River Estuary

et al. 2022

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Long‐chain alkyl diols (LCDs) were applied as indicators of salinity, sea surface temperature (SST), upwelling, and nutrient conditions in marine settings. While increasing the body of most applications of LCDs proxies reconstructed paleo‐environment information, few studies reported seasonal variation in LCDs and evaluated their applicability as environmental indicators in modern marine environments. Here, the composition and distribution of LCDs in suspended particulate matter (SPM) in three seasons in the Changjiang River Estuary (CRE) were analyzed to evaluate seasonal influence on the application of LCDs as environmental indicators. We found that the reconstructed temperature based on the long‐chain diol index (LDI; LDI = C30 1,15‐diol/(C28 1,13‐diol + C30 1,13‐diol + C30 1,15‐diol)) was not consistent with satellite‐measured SST, likely due to vertical mixing of LCDs in this region. The 1,14‐diols previously used to indicate upwelling conditions, did not reflect the nutrient distribution of this region due to the Changjiang River (CR) nutrients discharge. Our results showed that the mean relative proportions of FC32 1,15‐diol (FC32 1,15‐diol = C32 1,15‐diol × 100%/(C28 1,13‐diol + C30 1,13‐diol + C30 1,15‐diol + C32 1,15‐diol)) gradually decreased from nearshore to offshore (71.1%, 37.4%, and 16.5%, respectively), suggesting that FC32 1,15‐diol was a reliable proxy for riverine input to the CRE. We found that the diol index (DI; DI = C30 1,15‐diol × 100/(C30 1,15‐diol + C32 1,15‐diol)) values were correlated strongly with salinities in spring (R2 = 0.82) and summer (R2 = 0.94), indicating that DI can be considered as a useful indicator for salinity construction in this estuary.

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Evaluation of environmental proxies based on long chain alkyl diols in the East China Sea

Cited by 8 publications

References 51 publications

Evolutions of upwelling and terrestrial organic matter input in the inner shelf of the East China Sea in the last millennium revealed by long-chain alkyl diols proxies

Evolutions of upwelling and terrestrial organic matter input in the inner shelf of the East China Sea in the last millennium revealed by long-chain alkyl diols proxies

The Long chain Diol Index: A marine palaeotemperature proxy based on eustigmatophyte lipids that records the warmest seasons

Seasonal Variation of Long‐Chain Alkyl Diols Proxies in Suspended Particulate Matter of the Changjiang River Estuary

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