Variations in GDGT distributions through the water column in the South East Atlantic Ocean

Hernández-Sánchez, María Teresa; Woodward, E. Malcolm S.; Taylor, Kyle; Henderson, Gideon M.; Pancost, Richard D.

doi:10.1016/j.gca.2014.02.009

Cited by 58 publications

(43 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…6d), suggesting that the GDGT-2 and GDGT-3 are key components causing the bias of TEX 86 in the transitional zone. Similar observations were made by Taylor et al (2013) and Hernandez-Sanchez et al (2014) for other marine environments. On the other hand, the variation of GDGT-1 and crenarchaeol regioisomer exhibited no correlation with TEX 86 in this region (data not shown), suggesting that these two compounds may have little impact on the variation of TEX 86 in the transitional zone.…”

Section: Possible Mechanisms For the Unusually Low Tex 86 In The Transupporting

confidence: 88%

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

et al. 2015

View full text Add to dashboard Cite

Section: Possible Mechanisms For the Unusually Low Tex 86 In The Transupporting

confidence: 88%

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

et al. 2015

View full text Add to dashboard Cite

“…Similarly, TEX 86 warming observed within oxygen minimum zones is likely caused by energy stress and a corresponding decrease in ammonia oxidation rates; that is, it is not directly caused by physiological response to low O 2 as suggested by Qin et al (22). This explains why the subsurface TEX 86 warming trend also is observed in welloxygenated water columns and not limited only to oxygen minimum zones (23,27). In contrast, cold TEX 86 temperatures are observed in surface sediments and SPM at high-nutrient/highproductivity sites such as upwelling systems (e.g., refs.…”

Section: Cellular Energy Balance and The Synthesis Of Gdgts: The Redumentioning

confidence: 80%

“…Although it is now acknowledged that other factors such as community dynamics (e.g., refs. 29, 34) may affect TEX 86 and that in situ temperatures and TEX 86 are decoupled in the global subsurface ocean (23)(24)(25)(26)(27)(28), these arguments remain centered around a temperature-driven response.…”

Section: Discussionmentioning

confidence: 99%

“…Culture studies have shown that the average number of cyclopentyl moieties in GDGTs can increase with growth temperature in marine Archaea (19)(20)(21)(22); however, TEX 86 values of suspended particulate material (SPM) through the water column do not reflect in situ temperatures either in trend or in magnitude (23)(24)(25)(26)(27)(28)(29). TEX 86 -calculated temperatures in sinking particles and core-top sediments are often colder than mean annual average, especially in highly productive regions such as upwelling systems (30)(31)(32)(33).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Influence of ammonia oxidation rate on thaumarchaeal lipid composition and the TEX ₈₆ temperature proxy

Hurley

Elling

Könneke

et al. 2016

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

133

142

View full text Add to dashboard Cite

Archaeal membrane lipids known as glycerol dibiphytanyl glycerol tetraethers (GDGTs) are the basis of the TEX 86 paleotemperature proxy. Because GDGTs preserved in marine sediments are thought to originate mainly from planktonic, ammonia-oxidizing Thaumarchaeota, the basis of the correlation between TEX 86 and sea surface temperature (SST) remains unresolved: How does TEX 86 predict surface temperatures, when maximum thaumarchaeal activity occurs below the surface mixed layer and TEX 86 does not covary with in situ growth temperatures? Here we used isothermal studies of the model thaumarchaeon Nitrosopumilus maritimus SCM1 to investigate how GDGT composition changes in response to ammonia oxidation rate. We used continuous culture methods to avoid potential confounding variables that can be associated with experiments in batch cultures. The results show that the ring index scales inversely (R 2 = 0.82) with ammonia oxidation rate (ϕ), indicating that GDGT cyclization depends on available reducing power. Correspondingly, the TEX 86 ratio decreases by an equivalent of 5.4°C of calculated temperature over a 5.5 fmol·cell −1 ·d −1 increase in ϕ. This finding reconciles other recent experiments that have identified growth stage and oxygen availability as variables affecting TEX 86 . Depth profiles from the marine water column show minimum TEX 86 values at the depth of maximum nitrification rates, consistent with our chemostat results. Our findings suggest that the TEX 86 signal exported from the water column is influenced by the dynamics of ammonia oxidation. Thus, the global TEX 86 -SST calibration potentially represents a composite of regional correlations based on nutrient dynamics and global correlations based on archaeal community composition and temperature.T he glycerol dibiphytanyl glycerol tetraether (GDGT) membrane lipids of Archaea are abundant in marine water columns and sediments. The major source of GDGTs to ocean sediments is thought to be planktonic, ammonia-oxidizing Archaea (AOA) affiliated with the phylum Thaumarchaeota (formerly Marine Group I Crenarchaeota) (1, 2). Thaumarchaeota play a primary role in the nitrogen cycle, performing the first and rate-limiting step of nitrification-namely, the oxidation of ammonia to nitrite (3-5). Accordingly, Thaumarchaeota are most abundant at the base of, or below, the euphotic zone (6-9). Based on the phylogeny of their ammonia monooxygenase gene, the planktonic Thaumarchaeota are divided into two distinct clusters, the Water Column Cluster A that is most abundant in the epi-and upper mesopelagic (above ∼200 to ∼500 m, depending on location) and the Water Column Cluster B that dominates thaumarchaeal assemblages in the deeper mesopelagic and bathypelagic (7-10). These clusters putatively represent thaumarchaeal ecotypes adapted to high and low ammonium flux, respectively (11,12).Thaumarchaeota produce GDGTs containing from zero to four cyclopentane rings (GDGT-0 to GDGT-4) or four cyclopentane rings and one additional cyclohexane ring (e.g., in crenarchaeol;...

show abstract

“…As Thaumarchaeota live throughout the water column [ Karner et al , ], it is also likely that subsurface archaea are exported to sediments [ Pearson et al , ; Shah et al , ; Taylor et al , ; Hernández‐Sánchez et al , ]. During the Eocene, unexpectedly large offsets between TEX 86 H and TEX 86 L (ΔH‐L) are observed above 15°C [ Hollis et al , ].…”

Section: Introductionmentioning

confidence: 99%

Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions

et al. 2015

View full text Add to dashboard Cite

The TEX 86 proxy, based on the distribution of marine isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs), is increasingly used to reconstruct sea surface temperature (SST) during the Eocene epoch (56.0-33.9 Ma). Here we compile published TEX 86 records, critically reevaluate them in light of new understandings in TEX 86 palaeothermometry, and supplement them with new data in order to evaluate long-term temperature trends in the Eocene. We investigate the effect of archaea other than marine Thaumarchaeota upon TEX 86 values using the branched-to-isoprenoid tetraether index (BIT), the abundance of GDGT-0 relative to crenarchaeol (%GDGT-0), and the Methane Index (MI). We also introduce a new ratio, % GDGT RS , which may help identify Red Sea-type GDGT distributions in the geological record. Using the offset between TEX 86 H and TEX 86 L (ΔH-L) and the ratio between GDGT-2 and GDGT-3 ([2]/[3]), we evaluate different TEX 86 calibrations and present the first integrated SST compilation for the Eocene (55 to 34 Ma). Although the available data are still sparse some geographic trends can now be resolved. In the high latitudes (>55°), there was substantial cooling during the Eocene (~6°C). Our compiled record also indicates tropical cooling of~2.5°C during the same interval. Using an ensemble of climate model simulations that span the Eocene, our results indicate that only a small percentage (~10%) of the reconstructed temperature change can be ascribed to ocean gateway reorganization or paleogeographic change. Collectively, this indicates that atmospheric carbon dioxide (pCO 2 ) was the likely driver of surface water cooling during the descent toward the icehouse.

show abstract

Variations in GDGT distributions through the water column in the South East Atlantic Ocean

Cited by 58 publications

References 62 publications

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

Influence of ammonia oxidation rate on thaumarchaeal lipid composition and the TEX ₈₆ temperature proxy

Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions

Contact Info

Product

Resources

About

Variations in GDGT distributions through the water column in the South East Atlantic Ocean

Cited by 58 publications

References 62 publications

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

Unusually low TEX86 values in the transitional zone between Pearl River estuary and coastal South China Sea: Impact of changing archaeal community composition

Influence of ammonia oxidation rate on thaumarchaeal lipid composition and the TEX 86 temperature proxy

Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions

Contact Info

Product

Resources

About

Influence of ammonia oxidation rate on thaumarchaeal lipid composition and the TEX ₈₆ temperature proxy