Materials and Methods

Introduction

Results and Discussion

Acknowledgements

References Cited

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Hopmans, E.C., Weijers, J.W.H., Schefuß, E., Herfort, L., Sinninghe Damsté, J.S., Schouten, S., 2004. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids. Earth Planet. Sci. Lett. 224, 107–116.

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Kim, J.-H., van der Meer, J., Schouten, S., Helmke, P., Willmott, V., Sangiorgi, F., Koç, N., Hopmans, E.C., Sinninghe Damsté, J.S., 2010. New indices and calibrations derived from the distribution of crenarchaeal isoprenoid tetraether lipids: implications for past sea surface temperature reconstructions. Geochim. Cosmochim. Acta 74, 4639–4654.

Lee, K.E., Kim, J.-H., Wilke, I., Helmke, P., Schouten, S., 2008. A study of the alkenone, TEX86, and planktonic foraminifera in the Benguela upwelling system: implications for past sea surface temperature estimates. Geochem. Geophys. Geosyst. 9. doi:10.1029/2008GC002056 Q10019.

Lipp, J.S., Morono, Y., Inagaki, F., Hinrichs, K.-U., 2008. Significant contribution of Archaea to extant biomass in marine subsurface sediments. Nature 454, 991–994.

Menzel, D., Hopmans, E.C., Schouten, S., Sinninghe Damsté, J.S., 2006. Membrane tetraether lipids of planktonic Crenarchaeota in Pliocene sapropels of the Eastern Mediterranean Sea. Palaeogeogr. Palaeoclimatol. Palaeoecol. 239, 1–15.

Pearson, P.N., van Dongen, B.E., Nicholas, C.J., Pancost, R.D., Schouten, S., Singano, J.M., Wade, B.S., 2007. Stable warm tropical climate through the Eocene Epoch. Geology 35, 211–214.

Powers, L.A., Werne, J.P., Johnson, T.C., Hopmans, E.C., Sinninghe Damsté, J.S., Schouten, S., 2004. Crenarchaeotal membrane lipids in lake sediments: a new paleotemperature proxy for continental paleoclimate reconstruction? Geology 32, 613–616.

Schouten, S., Hopmans, E.C., Schefuss, E., Sinninghe Damsté, J.S., 2002. Distributional variations in marine crenarchaeotal membrane lipids: a new tool for reconstructing ancient sea water temperatures? Earth Planet. Sci. Lett. 204, 265–274.

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Zhang, C.L., Wang, J., Wei Y., Zhu, Y., Huang L., Dong H., 2012. Production of branched tetraether lipids in the lower Pearl River and estuary: effects of exraction methods and impact on bGDGT proxies. Fron. Micro. Doi: 10.3389/fmicb. 2011. 00274.

Zhu, C., Weijers, J., Wagner T., Pan J., Chen J., Pancost R.D., 2011. Sources and distributions of tetraether lipids in surface sediments across a large river-dominated continental margin. Org. Geo 42, 376 – 386.

We thank Dai L., Li Y., Zhong D., Hong Y.,Wong C., and Shao L. for helping with the sampling and analysis of greatly appreciated for helping with the field experiments during the cruise. This research was supported by the South China Sea-Deep program of the National Science Foundation of China (91028005) and the State Key Laboratory of Marine Geology of Tongji University. some of the samples collected for this study. Captain Deng was

Sediment and suspended particulate matter samples were collected from the lower Pearl River and the Pearl River Estuary, in China SE.

ConclusionsLC-MS/MS analysis 3. Comparisons of TEX86-derived temperatures to satellite-based water surface temperatures in the lower Pearl River and estuary.

Detection was performed using the Agilent 6460 triple-quadrupole spectrometer MS with an atmospheric pressure chemical ionization (APCI) ion source.

Lipid extraction and fractionation followed the procedure described in Zhang et al. (2012).

The GDGTs were analyzed on an Agilent 1200 liquid chromatography equipped with an automatic injector coupled to QQQ 6460 MS and Mass Hunter LC-MS manager software using a procedure modified from Schouten et al. (2007).

Sampling

Jinxiang Wang (jinxiang@uga.edu), Chuanlun Zhang (archaea.zhang@gmail.com) (Department of Marine Sciences, Univ. of Georgia, Athens, 30602, USA & State Key Laboratory of Marine Geology, Tongji Univ., Shanghai, 200092, China)

PP43B-2029

The TEX86 temperature proxy is based on archaeal glycerol

dialkyl glycerol tetraethers (GDGTs), which are abundant in river system (Hopmans et al., 2004; Herfort et al., 2006; Zhu et al., 2011). The biological sources are non-hyperthermophilic cren- and euryarchaeota, a major group of prokaryotes in today’s oceans and lakes (Karner et al., 2001; Powers et al., 2004).The relative distribution of these isoprenoidal GDGTs varies with growth temperature and linear regressions of core-top TEX86 values to SST enable the use of the TEX86 as a

temperature proxy (Kim et al., 2008, 2010; Schouten et al., 2002, 2007; Wuchter et al., 2005). Although, the TEX86 is increasingly used for reconstructing

ancient SSTs, a number of issues remain unresolved (Huguet et al., 2006; Pearson et al., 2007). It appears that the TEX86 can

be biased due to additional production of GDGTs below the mixed layer (Huguet et al., 2007; Lee et al., 2008), by seasonality in crenarchaeotal growth (Herfort et al., 2006; Menzel et al., 2006; Schouten et al., 2002) and by the ecology of planktonic cren- and euryarchaeota due to their presence in different water depths of the ocean and the theoretical possibility of GDGT synthesis by marine euryarchaeota (Delong, 2006; Wuchter et al., 2005). Additionally, archaea living in sediments of continental margins and the deep-sea may contribute to the GDGT pool and thus influence the TEX86 vale (Lipp et al., 2008; Shah et al., 2008). In coastal

settings, fluvial input of terrestrial isoprenoidal GDGTs may bias the TEX86 (Herfort et al., 2006).

 Here we present results of TEX86 from GDGTs analysis at

lower Pearl River and estuary, by comparing the results with available satellite-based water surface temperatures.

iso. Cren.GDGT3GDGT2GDGT1

iso. Cren.GDGT3GDGT2TEX86

)(TEX logTEX 86H86

C) 15 T(when 6.38TEX 68.4T H86

Estuary

Lower Pearl River

Liu et al., 2009

1. LC-MS/MS profiles of archaeal lipids

Filters-PLFilters-CL

Sediments-PLSediments-CL

2. Basic information on water depth, temperature, chemistry, nutrients, and particulates on filters.

Sample

WaterTemp.

ChemistrySPM

Core Lipids　 Polar Lipds 　 % PL (PL+CL)

depth pH

SAL TDS DO PO43- SiO4

2- NH4+ NO2

- NO3- DOC DIC iGDGTs iGDGTs iGDGTs

(m) ( )℃ ( )﹪ (g/l) (mg/l) (µmol/l) (µmol/l) (µmol/l) (µmol/l) (µmol/l) (mg/l) (mg/l) (mg/l) (μg/g spm) 　 (μg/g spm) 　 (%)

PR-F-9 2 30.7 5.8 0.0 0.2 3.9 1.5 155.0 63.0 2.4 315.2 3.3 18.4 n.c. n.c.　 n.c.　 n.c.

PR-F-8 2 30.2 5.4 0.0 0.1 1.1 1.8 167.0 120.1 1.1 600.6 5.1 10.6 11.3 5.90 2.49 29.67

PR-F-10 2 31.3 5.8 0.0 0.2 3.4 1.7 156.1 107.5 10.6 537.4 3.5 16.1 9.5 6.26 1.32 17.46

PR-F-7 2 30.2 5.2 0.0 0.1 0.8 1.2 168.4 100.6 0.4 503.2 2.5 11.8 17.6 2.23 0.50 18.32

PR-F-6 2 30.3 5.2 0.0 0.2 1.7 0.8 162.0 93.1 0.9 465.5 2.1 13.9 19.4 3.02 0.43 12.37

PR-F-5 2 30.2 5.2 0.0 0.2 1.9 0.7 163.9 126.5 0.9 632.3 2.6 13.2 6.4 1.74 1.01 36.74

PR-F-4 2 30.3 5.7 0.0 0.2 6.5 0.6 151.3 53.9 7.0 269.3 1.1 17.6 20.1 0.73 0.25 25.60

PR-F-3 1 30.1 5.3 0.0 0.2 3.2 0.9 162.5 107.0 1.3 535.1 2.8 13.5 20.3 2.10 0.42 16.77

PR-F-2 1 30.4 5.4 0.0 0.2 3.0 0.6 160.9 128.7 25.0 643.3 3.8 14.2 50.7 0.98 0.28 22.16

PR-F-1 3 29.8 5.2 0.0 0.2 1.4 0.7 156.4 108.0 30.9 540.0 1.5 13.4 28.9 2.66 0.69 20.60

PR-F-11S 1 30.1 6.3 0.1 1.2 4.4 1.0 139.1 22.3 17.1 111.5 1.2 18.1 14.7 0.77 0.20 20.72

PR-F-11D 4 30.0 6.3 0.1 1.2 4.5 1.0 138.6 29.5 16.4 147.3 3.0 19.0 n.c. n.c. n.c. n.c.

PR-F-12S 1 31.0 6.7 0.0 0.3 7.3 0.9 119.4 18.3 3.2 91.5 4.1 21.4 126.8 0.37 0.04 9.94

PR-F-12D 10 28.0 7.3 2.2 21.0 3.3 1.0 63.7 24.7 7.6 123.7 1.8 23.5 23.0 1.96 1.06 35.20

PR-F-13S 1 30.5 7.4 0.8 9.0 8.9 0.9 109.6 22.1 10.9 110.4 1.4 19.8 5.7 1.75 1.13 39.29

PR-F-13D 5 28.7 7.3 2.0 19.0 4.5 1.1 76.9 21.6 9.7 108.1 2.0 22.2 25.7 1.15 0.46 28.78

PR-F-14S 1 30.1 8.1 1.5 16.0 11.1 0.6 51.4 19.3 5.1 96.3 1.3 20.2 14.7 1.15 0.84 42.30

PR-F-14D 17 24.2 7.6 3.6 32.0 1.7 0.6 25.4 27.2 1.9 135.8 1.9 27.1 23.0 1.47　 0.74　 33.29

3. Comparisons of TEX86-derived temperatures to the satellite-based water surface temperatures and measured monthly mean air temperatures of the lower Pearl River drainage basin.

Greater abundances of PL-GDGTs and CL-GDGTs were found in the lower Pearl River.

The TEX86H temperature for CL-GDGTs reflect the annual

mean surface water temperature; whereas, the TEX86H

temperatures for PL-GDGTs have the potential to respond to seasonal variation.

In situ production of P-GDGTs in surface sediments may complicate the TEX86

H – derived temperatures in the estuary.

Caution needs to be excised when interpreting low TEX86H –

derived temperature as winter signals in paleo – coastal climate studies.

Two different compositions of GDGTs were separated by the interface, which was located in the boundary the lower Pearl River and estuary.

Most of the PL-GDGTs where produced in the in-situ environments.

TEX86H temperature for C-GDGTs ranged from 21.2℃ to 26.9℃ for suspended

particles, which were close to satellite-based annual mean water temperature (average 24.6±0.1℃); whereas the TEX86 temperatures for P-GDGTs have the potential to respond to satellite-based July mean water surface temperature.

The in situ production of PL-GDGTs in the sediments contributed to the good correlation between TEX86

H of PL-GDGTs derived temperature and satellite-based winter mean water surface temperature.

Terrestrial input of PL-GDGTs may be one of the maim reasons to cause the TEX86

H of PL-GDGTs derived temperature to be higher than satellite-based annual mean water temperature.

TEX86H of CL and PL derived temperatures in soil highly correlated with monthly

average air temperature in July.

The TEX86H of CL-GDGTs derived temperatures have more stability than that of PL-

GDGTs derived temperatures in sediments and filters.

TEX86H derived temperature is not affected by extraction method when

calculations are performed using the CL-GDGTs; Yet, it’s better to use the B-D method to do extraction when calculations are performed using the PL-GDGTs.

BD ProtocolSilica column

Polar Fraction

Apolar Fraction

Acid Hydrolysis

LC-MS

AR

GDGT (0)#9

AR

GDGT (0)

Crenarchaeol

#1

GDGT (0)#12B

AR

GDGT (0)

Crenarchaeol

#12S

GDGT (0)

Crenarchaeol

#14

Lower Pearl River Estuary SCS

Crenarchaeol

Crenarchaeol

Crenarchaeol

GDGT (0)GDGT (0)

GDGT (0)Sedi - #9

Soil - #1 Soil - #19

Sedi - #1

Sedi - #12

Sedi - #14