Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers using lignin phenols and long-chain n-alkanes as biomarkers

2021 ◽  
Author(s):  
Mengli Cao ◽  
Jens Hefter ◽  
Ralf Tiedemann ◽  
Lester Lembke-Jene ◽  
Gesine Mollenhauer
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Sediment Cores ◽  
Okhotsk Sea ◽  
Accumulation Rates ◽  
Amur Basin ◽  
Lignin Phenols ◽  
Wetland Extent ◽  
Mass Accumulation Rates ◽  
Mass Accumulation

<p>Anthropogenic climate change has profound impacts on Arctic temperatures, with consequences for Arctic ecosystems and landscapes, and the stability of organic-rich permafrost deposits. When mobilized, these permafrost deposits might release vast amounts of greenhouse gases. We use periods of past rapid warming in the high latitudes as analogues to study the ecological changes and effects on permafrost stability under climate change. We used marine sediment cores from the Bering and Okhotsk Sea continental margins, off the mouths of the Yukon and Amur rivers, to study two types of terrigenous biomarkers, which trace different terrestrial organic carbon (OC) components and transport pathways, and cover the early deglaciation to the early Holocene. The Yukon basin remains within the permafrost-affected region today, whereas the Amur basin changed from being subject to complete permafrost cover during the last glacial to permafrost-free conditions today. </p><p>Vascular plant-derived lignin phenols were analyzed and compared to published n-alkane content data. The carbon- and sediment-normalized contents of the vanillyl phenols (V), syringyl phenols (S), and cinnamyl phenols (C) phenols (Λ8 and Σ8) reflect the content of lignin dominantly transported by river runoff. The C/V and S/V ratios serve to distinguish between woody and non-woody tissues of angiosperms and gymnosperms. The acid to aldehyde ratios of V and S phenols ((Ad/Al)<sub>V</sub> and (Ad/Al)<sub>S</sub>) indicate the degree of lignin degradation. In addition, the ratio of 3,5-dihydroxybenzoic acid to V (3,5Bd/V) likely reflects the wetland extent, while lignin reflects primarily transportation into the marine sediment via surface runoff. In contrast, the n-alkane contents represent primarily terrigenous organic matter eroded from deeper deposits and a second marker for wetland extent via the Paq index. Lignin and n-alkane mass accumulation rates (MAR) can thus be used to reconstruct the mobilization of different carbon pools and the relative timing of the processes leading to their export to the ocean.</p><p>The MAR of biomarkers and the wetland indicators 3,5 Bd/V and Paq start to increase in the Bering Sea sediment during the early deglaciation (19-14.6 ka BP), while no obvious change in lignin MAR in the Okhotsk Sea occurred during this time. We observe distinct peaks of mass accumulation rates, wetland indices and indicators for degradation of lignin (Ad/Al) in both sediment cores during the warm Bølling-Allerød (12.9-14.6 ka BP) and Pre-Boreal (9-11.5 ka BP) intervals, and during the Younger Dryas cold spell (11.5-12.9 ka BP). In contrast, in the Okhotsk Sea, the ratios of S/V and C/V did not change before the Preboreal. </p><p>Our biomarker data suggest that the permafrost in the Yukon basin may have started to be remobilized by inland warming leading to wetland development in the early deglaciation, while the onset of permafrost degradation in the Amur basin occurred during the Preboreal.</p>

scholarly journals Productivity patterns and N-fixation associated with Pliocene-Holocene sapropels: paleoceanographic and paleoecological significance

2011 ◽  
Vol 8 (2) ◽  
pp. 415-431 ◽  
Author(s):  
D. Gallego-Torres ◽  
F. Martinez-Ruiz ◽  
P. A. Meyers ◽  
A. Paytan ◽  
F. J. Jimenez-Espejo ◽  
...  
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
N Fixation ◽  
Accumulation Rates ◽  
Ecological Changes ◽  
Bottom Waters ◽  
Mass Accumulation Rates ◽  
Mass Accumulation

Abstract. We have studied a suite of 35 sapropel sequences from a transect of four ODP sites across the Eastern Mediterranean to explore for paleoproductivity patterns and provide new insights on ecological changes during their deposition. Paleoproductivity variations were identified using TOC and Babio mass accumulation rates and δ15Ntotal and δ13Corg values. Elevated Ba/Al and TOC mass accumulation rates record periods of basin-wide amplified productivity. Our data further support that sapropels were formed by cyclic increases in primary production of marine organic matter largely sustained by N-fixing bacteria. This productivity increase was triggered by climate factors leading to increased fluvial discharge and amplified nutrient input that also favored the establishment of N-fixing bacteria. Enhanced productivity led to depletion of deepwater dissolved oxygen and consequently improved organic matter preservation. Primary production was more intense during the middle to Late Pleistocene compared to Pliocene equivalents, coinciding with increasing total sedimentation rates. δ15N values are dramatically lower in the sapropels than in TOC-poor background sediments, indicating a major contribution from nitrogen-fixing bacteria to the higher productivity during sapropel deposition. Additionally, different degrees of denitrification occurred as a consequence of water column oxygenation which in turns evolved from stagnant anoxic bottom waters during Pliocene sapropels to oxygen depleted and sluggish circulation in late Quaternary layers. These differences between sapropel layers provide new evidences for the general evolution of the Eastern Mediterranean basin during the last 3 Mys in terms of paleoceanographic conditions and the intensity of climate variability leading to sapropel deposition.

scholarly journals Radiocarbon Dating, Chronologic Framework, and Changes in Accumulation Rates of Holocene Estuarine Sediments from Chesapeake Bay

2002 ◽  
Vol 57 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Steven M. Colman ◽  
Pattie C. Baucom ◽  
John F. Bratton ◽  
Thomas M. Cronin ◽  
John P. McGeehin ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
Deep Water ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Complex Mixture ◽  
Estuarine Sediments ◽  
Accumulation Rates ◽  
Pollen Stratigraphy ◽  
Mass Accumulation Rates ◽  
Mass Accumulation

AbstractRapidly accumulating Holocene sediments in estuaries commonly are difficult to sample and date. In Chesapeake Bay, we obtained sediment cores as much as 20 m in length and used numerous radiocarbon ages measured by accelerator mass spectrometry methods to provide the first detailed chronologies of Holocene sediment accumulation in the bay. Carbon in these sediments is a complex mixture of materials from a variety of sources. Analyses of different components of the sediments show that total organic carbon ages are largely unreliable, because much of the carbon (including coal) has been transported to the bay from upstream sources and is older than sediments in which it was deposited. Mollusk shells (clams, oysters) and foraminifera appear to give reliable results, although reworking and burrowing are potential problems. Analyses of museum specimens collected alive before atmospheric nuclear testing suggest that the standard reservoir correction for marine samples is appropriate for middle to lower Chesapeake Bay. The biogenic carbonate radiocarbon ages are compatible with 210Pb and 137Cs data and pollen stratigraphy from the same sites.Post-settlement changes in sediment transport and accumulation is an important environmental issue in many estuaries, including the Chesapeake. Our data show that large variations in sediment mass accumulation rates occur among sites. At shallow water sites, local factors seem to control changes in accumulation rates with time. Our two relatively deep-water sites in the axial channel of the bay have different long-term average accumulation rates, but the history of sediment accumulation at these sites appears to reflect overall conditions in the bay. Mass accumulation rates at the two deep-water sites rapidly increased by about fourfold coincident with widespread land clearance for agriculture in the Chesapeake watershed.

scholarly journals Phosphorus burial in the ocean over glacial-interglacial time scales

2008 ◽  
Vol 5 (6) ◽  
pp. 5133-5162 ◽  
Author(s):  
F. Tamburini ◽  
K. B. Föllmi
Keyword(s):  
Climate Change ◽  
Global Scale ◽  
Interglacial Period ◽  
Accumulation Rates ◽  
The World ◽  
Mass Accumulation Rates ◽  
Mass Accumulation ◽  
Selection Of ◽  
The Last Glacial

Abstract. The role of nutrients and their impact on primary productivity and the fluctuations in atmospheric CO2 over glacial-interglacial periods are intensely debated. One of the cornerstones is the role of phosphorus (P; in the form of phosphate). Suggestions as to the importance of P evolved from an earlier proposal that P actively participated in changing productivity rates and therefore climate change, to the most recent one that changes in the glacial ocean inventory of phosphorus were small and not influential if compared to other macronutrients, such as nitrogen. Using new data coming from a selection of ODP sites, we illustrate oceanic P sedimentary phases distribution and reactive P burial fluxes, and we show how P burial fluxes changed over the last glacial-interglacial period. Concentrations of reactive P are generally lower during glacial times, while mass accumulation rates (MAR) show higher variability. On a global scale, glacial burial fluxes of reactive P are lower than those during interglacial periods by 7–10%, because lack of burial of reactive P on the glacial reduced shelf was apparently not compensated by burial in other regions of the ocean. Using the calculated changes in P burial, we try to infer their possible impact on the phosphate inventory in the world oceans. Using a simple mathematical approach, we find that these changes alone could have increased the phosphate inventory of glacial ocean waters by 20–40% compared to interglacial stages. Variations in the C/P reactive ratios and in the P sedimentary phases distribution at the investigated sites seem to indicate that at the onset of interglacial stages, shallower sites experienced an increase in reactive P concentrations. This seems to point to P-richer waters at glacial terminations, supporting the shelf-nutrient hypothesis and giving phosphorus a role as a potential player in climate change.

scholarly journals Productivity patterns and N-fixation associated with Pliocene-Holocene sapropels: paleoceanographic and paleoecological significance

2010 ◽  
Vol 7 (3) ◽  
pp. 4463-4503
Author(s):  
D. Gallego-Torres ◽  
F. Martínez-Ruiz ◽  
P. A. Meyers ◽  
A. Paytan ◽  
F. J. Jimenez-Espejo ◽  
...  
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Eastern Mediterranean ◽  
Oxygen Depletion ◽  
Middle Pleistocene ◽  
N Fixation ◽  
Sedimentation Rates ◽  
Accumulation Rates ◽  
Mass Accumulation Rates ◽  
Mass Accumulation

Abstract. Sapropels are organic matter enriched sediments cyclically deposited in the Eastern Mediterranean. We have studied a suite of 35 sapropel sequences from a transect of four ODP sites across the basin to explore for paleoproductivity patterns and their relationship to ecological changes in the region during their deposition. We assessed paleoproductivity variations using TOC and Babio mass accumulation rates and δ15Ntotal and δ13Corg values. Elevated Ba/Al and TOC mass accumulation rates record periods of basin-wide amplified productivity. δ15N values are dramatically lower in the sapropels than in TOC-poor background sediments indicating a major contribution from nitrogen-fixing bacteria to the higher productivity during sapropel deposition. Different degrees of denitrification occurred as a function of water column oxygen depletion. The evolution of sapropel deposition over the past 3 My is characterized by increased productivity together with enhanced preservation of organic matter during the late Pliocene, peaks in primary and export production and sedimentation rates during the middle Pleistocene, and a relatively weak increase in productivity during formation of the Holocene sapropel accompanied by high sedimentation rates. We conclude that sapropels were formed by cyclic increases in primary production of marine organic matter largely sustained by N-fixing bacteria that led to depletion of deepwater dissolved oxygen and consequently improved organic matter preservation. The increase in primary production was helped by nutrient input from continental sources climatically induced.

scholarly journals Quartz OSL dating of late quaternary Chinese and Serbian loess: A cross Eurasian comparison of dust mass accumulation rates

2019 ◽  
Vol 502 ◽  
pp. 30-44 ◽  
Author(s):  
Zoran Perić ◽  
Emma Lagerbäck Adolphi ◽  
Thomas Stevens ◽  
Gábor Újvári ◽  
Christian Zeeden ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Osl Dating ◽  
Accumulation Rates ◽  
Dust Mass ◽  
Mass Accumulation Rates ◽  
Mass Accumulation

scholarly journals Phosphorus burial in the ocean over glacial-interglacial time scales

2009 ◽  
Vol 6 (4) ◽  
pp. 501-513 ◽  
Author(s):  
F. Tamburini ◽  
K. B. Föllmi
Keyword(s):  
Primary Productivity ◽  
Deep Sea ◽  
Interglacial Period ◽  
Accumulation Rates ◽  
The World ◽  
Mass Accumulation Rates ◽  
Mass Accumulation ◽  
Selection Of ◽  
The Last Glacial

Abstract. The role of nutrients, such as phosphorus (P), and their impact on primary productivity and the fluctuations in atmospheric CO2 over glacial-interglacial periods are intensely debated. Suggestions as to the importance of P evolved from an earlier proposal that P actively participated in changing productivity rates and therefore climate change, to most recent ones that changes in the glacial ocean inventory of phosphorus were important but not influential if compared to other macronutrients, such as nitrate. Using new data coming from a selection of ODP sites, we analyzed the distribution of oceanic P sedimentary phases and calculate reactive P burial fluxes, and we show how P burial fluxes changed over the last glacial-interglacial period at these sites. Concentrations of reactive P are generally lower during glacial times, while mass accumulation rates (MAR) of reactive P show higher variability. If we extrapolate for the analyzed sites, we may assume that in general glacial burial fluxes of reactive P are lower than those during interglacial periods by about 8%, because the lack of burial of reactive P on the glacial shelf reduced in size, was apparently not compensated by burial in other regions of the ocean. Using the calculated changes in P burial, we evaluate their possible impact on the phosphate inventory in the world oceans. Using a simple mathematical approach, we find that these changes alone could have increased the phosphate inventory of glacial ocean waters by 17–40% compared to interglacial stages. Variations in the distribution of sedimentary P phases at the investigated sites seem to indicate that at the onset of interglacial stages, shallower sites experienced an increase in reactive P concentrations, which seems to point to P-richer waters at glacial terminations. All these findings would support the Shelf-Nutrient Hypothesis, which assumes that during glacial low stands nutrients are transferred from shallow sites to deep sea with possible feedback on the carbon cycle.

scholarly journals Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives

2014 ◽  
Vol 10 (6) ◽  
pp. 4277-4363 ◽  
Author(s):  
S. Albani ◽  
N. M. Mahowald ◽  
G. Winckler ◽  
R. F. Anderson ◽  
L. I. Bradtmiller ◽  
...  
Keyword(s):  
North Atlantic ◽  
Accumulation Rates ◽  
Dust Deposition ◽  
The Holocene ◽  
The North ◽  
Dust Mass ◽  
The North Atlantic ◽  
Mass Accumulation Rates ◽  
Mass Accumulation ◽  
Natural Archives

Abstract. Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP paleodust datasets in the last two decades provided a target for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust dataset that moves on from the positive experience of DIRTMAP and takes into account new scientific challenges, by providing a concise and accessible dataset of temporally resolved records of dust mass accumulation rates and particle grain-size distributions. We consider data from ice cores, marine sediments, loess/paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows investigation of the potential, uncertainties and confidence level of dust mass accumulation rates reconstructions, and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 43 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggest that minimum dust fluxes are likely observed during the Early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize datasets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate the mass balance and variability of the global dust cycle during the Holocene, with dust load ranging from 17.1 to 20.5 Tg between 2000 and 10 000 years ago, and a minimum in the Early to Mid-Holocene (6000–8000 years ago).

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