Diatoms in Southeast Pacific surface sediments reflect environmental properties

Abrantes, Fatima F; Lopes, Cristina; Mix, Alan C; Pisias, Nicklas G

doi:10.1016/j.quascirev.2006.02.022

Cited by 67 publications

(27 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The younger sediments also contain abundant upwelling-indicative species such as Thalassionema nitzschioides and Chaetoceros sp. (Abrantes et al, 2007), whereby Chaetoceros brevis, a species from the Southern Ocean, has been shown to have a much higher ε of −2.1 ‰ (Sutton et al, 2013). That means, assuming the same surface water δ 30 Si Si(OH) 4 signatures, a dominance of Chaetoceros sp.…”

Section: Factors Influencing the Reconstruction Of The Utilisation Simentioning

confidence: 99%

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

et al. 2015

View full text Add to dashboard Cite

Abstract. For this study two sediment cores from the Peruvian shelf covering the time period between the Little Ice Age (LIA) and present were examined for changes in productivity (biogenic opal concentrations (bSi)), nutrient utilisation (stable isotope compositions of silicon (δ 30 Si opal ) and nitrogen (δ 15 N sed )), as well as in ocean circulation and material transport (authigenic and detrital radiogenic neodymium (ε Nd ) and strontium ( 87 Sr / 86 Sr) isotopes).For the LIA the proxies recorded weak primary productivity and nutrient utilisation reflected by low average bSi concentrations of ∼ 10 %, δ 15 N sed values of ∼ 5 ‰ and intermediate δ 30 Si opal values of ∼ 0.9 ‰. At the same time, the radiogenic isotope composition of the detrital sediment fraction indicates dominant local riverine input of lithogenic material due to higher rainfall in the Andean hinterland. These patterns were most likely caused by permanent El Niño-like conditions characterised by a deeper nutricline, weak upwelling and low nutrient supply. At the end of the LIA, δ 30 Si opal dropped to low values of +0.6 ‰ and opal productivity reached its minimum of the past 650 years. During the following transitional period of time the intensity of upwelling, nutrient supply and productivity increased abruptly as marked by the highest bSi contents of up to 38 %, by δ 15 N sed of up to ∼ 7 ‰, and by the highest degree of silicate utilisation with δ 30 Si opal reaching values of +1.1 ‰. At the same time, detrital ε Nd and 87 Sr / 86 Sr signatures documented increased wind strength and supply of dust to the shelf due to drier conditions. Since about 1870, productivity has been high but nutrient utilisation has remained at levels similar to the LIA, indicating significantly increased nutrient availability.Comparison between the δ 30 Si opal and δ 15 N sed signatures suggests that during the past 650 years the δ 15 N sed signature in the Peruvian upwelling area has to a large extent been controlled by surface water utilisation and not, as previously assumed, by subsurface nitrogen loss processes in the water column, which only had a significant influence during modern times (i.e. since ∼ AD 1870).

show abstract

Section: Factors Influencing the Reconstruction Of The Utilisation Simentioning

confidence: 99%

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

et al. 2015

View full text Add to dashboard Cite

show abstract

“…It has been reported that transfer functions based on diatom and radiolarian species offer a reliable tool for estimating paleoceanographic changes in the SE Pacific [ Pisias et al , 1997, 2006; Abrantes et al , 2007], together with planktonic foraminifera [ Mix et al , 1999; Feldberg and Mix , 2002; Kucera et al , 2005b; Morey et al , 2005]. However, no transfer function using coccolithophores has been done for the SE Pacific.…”

Section: Introductionmentioning

confidence: 99%

Coccolithophore estimates of paleotemperature and paleoproductivity changes in the southeast Pacific over the past ∼27 kyr

et al. 2011

View full text Add to dashboard Cite

We provide high‐resolution sea surface temperature (SST) and paleoproductivity data focusing on Termination 1. We describe a new method for estimating SSTs based on multivariate statistical analyses performed on modern coccolithophore census data, and we present the first downcore reconstructions derived from coccolithophore assemblages at Ocean Drilling Project (ODP) Site 1233 located offshore Chile. We compare our coccolithophore SST record to alkenone‐based SSTs as well as SST reconstructions based on dinoflagellates and radiolaria. All reconstructions generally show a remarkable concordance. As in the alkenone SST record, the Last Glacial Maximum (LGM, 19–23 kyr B.P.) is not clearly defined in our SST reconstruction. After the onset of deglaciation, three major warming steps are recorded: from 18.6 to 18 kyr B.P. (∼2.6°C), from 15.7 to 15.3 kyr B.P. (∼2.5°C), and from 13 to 11.4 kyr B.P. (∼3.4°C). Consistent with the other records from Site 1233 and Antarctic ice core records, we observed a clear Holocene Climatic Optimum (HCO) from ∼8–12 kyr B.P. Combining the SST reconstruction with coccolith absolute abundances and accumulation rates, we show that colder temperatures during the LGM are linked to higher coccolithophore productivity offshore Chile and warmer SSTs during the HCO to lower coccolithophore productivity, with indications of weak coastal upwelling. We interpret our data in terms of latitudinal displacements of the Southern Westerlies and the northern margin of the Antarctic Circumpolar Current system over the deglaciation and the Holocene.

show abstract

“…Fragile diatoms are particularly susceptible to dissolution in the water column, at the watersediment interface and in the sediment and are accordingly rare in most sediments (Abrantes et al, 2007 and references herein). Therefore only a few studies on sediment cores report the presence of (unidentified) Pseudo-nitzschia species (Stabell and Hasle, 1996;Abrantes et al, 2007), whereas others did not find Pseudo-nitzschia species in sediments (e.g. Hemphill-Haley and Fourtanier, 1995;Dickman and Glenwright, 1997;Abrantes and Moita, 1999).…”

Section: Introductionmentioning

confidence: 99%

A 100-year record of changing Pseudo-nitzschia species in a sill-fjord in Denmark related to nitrogen loading and temperature

Lundholm

Clarke²,

Ellegaard

2010

Harmful Algae

View full text Add to dashboard Cite

Diatoms in Southeast Pacific surface sediments reflect environmental properties

Cited by 67 publications

References 51 publications

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

Coccolithophore estimates of paleotemperature and paleoproductivity changes in the southeast Pacific over the past ∼27 kyr

A 100-year record of changing Pseudo-nitzschia species in a sill-fjord in Denmark related to nitrogen loading and temperature

Contact Info

Product

Resources

About