Biomarker-derived phytoplankton community for summer monsoon reconstruction in the western South China Sea over the past 450ka

Li, Li; Li, Qianyu; He, Jin‐Sheng; Wang, Hui; Ruan, Yanming; Li, Jianru

doi:10.1016/j.dsr2.2015.11.006

Cited by 14 publications

(7 citation statements)

References 102 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During MZ-I, there was a predominance of diatoms and dinoflagellates, indicated by the concentrations above the long-term mean of 28D 5,22E and 30D 22E , respectively (Volkman, 1986). A similarity between 28D 5,22E and 30D 22E contents was also observed by Li et al (2015), indicating that diatoms and dinoflagellates respond similarly to hydrological variability. During the MZ-II and MZ-III, a relative increase in long-chain alkenones content, biomarkers produced by coccolithophores (Epstein et al, 2001), was observed.…”

Section: Composition Of the Marine Primary Producer Communitymentioning

confidence: 86%

“…Distinct primary producers characterized the MZs, and Figure 6B summarizes the variations in marine OM productivity and the relationship between these producers. Although differential degradation among different compounds during diagenesis makes it challenging to infer the abundance of living organisms from the biomarker data, their normalized MAR may reflect changes in the contribution of each specific group of organisms (Li et al, 2015). During MZ-I, there was a predominance of diatoms and dinoflagellates, indicated by the concentrations above the long-term mean of 28D 5,22E and 30D 22E , respectively (Volkman, 1986).…”

Section: Composition Of the Marine Primary Producer Communitymentioning

confidence: 99%

See 1 more Smart Citation

Late Pleistocene to Holocene variations in marine productivity and terrestrial material delivery to the western South Atlantic

et al. 2022

View full text Add to dashboard Cite

Despite the increased number of paleoceanographic studies in the SW Atlantic in recent years, the mechanisms controlling marine productivity and terrestrial material delivery to the South Brazil Bight remain unresolved. Because of its wide continental shelf and abrupt change in coastline orientation, this region is under the influence of several environmental forcings, causing the region to have large variability in primary production. This study investigated terrestrial organic matter (OM) sources and marine OM sources in the South Brazil Bight, as well as the main controls on marine productivity and terrestrial OM export. We analyzed OM geochemical (bulk and molecular) proxies in sediment samples from a core (NAP 63-1) retrieved from the SW Atlantic slope (24.8°S, 44.3°W, 840-m water depth). The organic proxies were classified into “terrestrial-source” and “marine-source” groups based on a cluster analysis. The two sources presented different stratigraphical profiles, indicating distinct mechanisms governing their delivery. Bulk proxies indicate the predominance of marine OM, although terrestrial input also affected the total OM deposition. The highest marine productivity, observed between 50 and 39 ka BP, was driven by the combined effects of the South Atlantic Central Water upwelling promoted by Brazil Current eddies and fluvial nutrient inputs from the adjacent coast. After the last deglaciation, decreased phytoplankton productivity and increased archaeal productivity suggest a stronger oligotrophic tropical water presence. The highest terrestrial OM accumulation occurred between 30 and 20 ka BP, with its temporal evolution controlled mainly by continental moisture evolution. Sea level fluctuations affected the distance between the coastline and the sampling site. In contrast, continental moisture affected the phytogeography, changing from lowlands covered by grasses and saltmarshes to a landscape dominated by mangroves and the Atlantic Forest. Our results suggest how the OM cycle in the South Brazil Bight may respond to warmer and dryer climate conditions.

show abstract

Section: Composition Of the Marine Primary Producer Communitymentioning

confidence: 86%

Section: Composition Of the Marine Primary Producer Communitymentioning

confidence: 99%

Late Pleistocene to Holocene variations in marine productivity and terrestrial material delivery to the western South Atlantic

et al. 2022

View full text Add to dashboard Cite

show abstract

“…In the northern and southern subbasins, relatively high PP occurs during winter in response to the stronger vertical mixing promoted by EAWM NE winds (Tian et al, 2005;Su et al, 2013;Su et al, 2015), while the EASM winds promote upwelling especially in the western SCS subbasin Chai, 2009). Hence, glacial stages have been characterized to be more productive than interglacial stages, since the EAWM is more intense than the EASM (Chen, 2005;Chai, 2009;Li et al, , 2015.…”

Section: Limitations Of Using Planktonic Foraminiferal Dissolution In...mentioning

confidence: 99%

“…We use NGR values obtained onboard on the whole-round core section using the Natural Gamma Radiation Logger (NGRL) published by Li et al (2015). The NGRL measures the natural emission from the decay of 238 U, 232 Th, 40 K, and their daughters, allowing to estimate the abundance of each of these isotopes according to their specific spectrum of emitted energy (Li et al, 2015c).…”

Section: Natural Gamma Radiation (Ngr)mentioning

confidence: 99%

“…Enhanced PP during MIS 8 is associated with stronger EAWM winds promoting upper water mixing, thus supplying nutrients to the surface waters(Su et al, 2013;Zhang et al, 2016; Figure 1.6). In contrast, during MIS 7, high abundance of Gephyrocapsa oceanica and an abrupt decrease in F. profunda observed at the western SCS subbasin (core MD05-2901,Su et al, 2013) would be a result of upwelling occurrence induced by the southerly EASM winds(Su et al, 2013;Li et al, 2015; Figure 1.6f, g). The strengthening of the EASM over the last ~400 kyr is recorded in Chinese cave speleothems, evidenced by more negative δ 18 O values(Cheng et al, 2009; Figure6g).…”

mentioning

confidence: 95%

See 1 more Smart Citation

>b<Carbonate system and elementary geochemistry>/b<: Paleoceanographic and paleoclimatic implications in the South China Sea along the Late Quaternary

Gerotto¹

View full text Add to dashboard Cite

Understanding past ocean carbonate chemistry changes is critical to elucidate the role of the oceans in the global carbon cycle and Earth's climate control according to its large carbon dioxide (CO2) storage capacity. The South China Sea (SCS) is a tropical basin of great interest for understanding the evolution of the carbonate system. This marginal basin is under the influence of the East Asian Monsoon (EAM) which has a profound impact on the interactions between the atmosphere, land, and oceans. In this context, the present work aims to evaluate changes in SCS carbon system considering the carbonate cycles that acted in the basin along with the Quaternary controlling dissolution and dilution processes. For this, we applied using a multiproxy approach in marine sedimentary samples from cores recovered in the eastern, northeast, and northern subbasins of the SCS -Hole IODP U1431D (4240 m depth), Hole U1432C (3829 m), and ODP 1146 (2092 m) -and in surface sediments collected along the basin (R/V Sonne, at depths between 629-3809 m. We evaluated (i) the abundance, fragmentation, and dissolution indexes of planktonic foraminifera and total organic carbon in the last 600 ka; (ii) terrigenous input by the determination of major and trace elements in sediments and variations in natural gamma radiation; and (iii) performed the calibration of morphological attributes of coccoliths in response to a laboratory dissolution experiment and oceanic environmental parameters, generating a new proxy that was applied in the reconstruction of dissolution patterns in the last 210 kyr. The results showed that the records located below the modern lysocline and carbonate compensation were under strong dissolution. A punctual increase in planktonic foraminifera abundance was related to primary productivity and EAM dynamics, with the occurrence of turbidites influencing CaCO3 preservation. Despite the low carbonate preservation inherent to the depth of these records, the dilution of biogenic sediments by the terrigenous input was recorded due to the more significant terrigenous contribution of sediments potentially sourced from Luzon in response to the strengthened summer EAM. The dissolution experiment and the evaluation of surface sediments showed that changes in coccolith morphology, obtained by the ks factor, are mainly controlled by changes in carbonate saturation, and can be used as a proxy to track changes in carbonate saturation limits. When applied as dissolution proxy the ks factor recorded changes possibly related to variations in lysocline depth over the last 210 kyr consistent with changes in deepwater circulation between the Pacific and the SCS. The results of this thesis demonstrate that post-burial dissolution has a major influence on the composition of micro and nannofossils assemblages and in the carbonate preservation at SCS sediments and that the coccolith ks factor is a reliable proxy for tracking changes in carbonate chemistry.

show abstract

The South China Sea Deep: Introduction

Wang

Dai

2015

Deep Sea Research Part II: Topical Studies in Oceanography

View full text Add to dashboard Cite

Biomarker-derived phytoplankton community for summer monsoon reconstruction in the western South China Sea over the past 450ka

Cited by 14 publications

References 102 publications

Late Pleistocene to Holocene variations in marine productivity and terrestrial material delivery to the western South Atlantic

Late Pleistocene to Holocene variations in marine productivity and terrestrial material delivery to the western South Atlantic

>b<Carbonate system and elementary geochemistry>/b<: Paleoceanographic and paleoclimatic implications in the South China Sea along the Late Quaternary

The South China Sea Deep: Introduction

Contact Info

Product

Resources

About