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TEX86 sea surface temperature compilation for the Eocene epoch (56 to 34 million years ago). Also included are other GDGT-based indices which are used to flag potentially problematic SST estimates. The data accompanies Inglis et al. (2015; Palaeoceanography, v.30, p. 1000-1020) DOI: 10.1002/2014PA002723 Sheet 1: The fractional abundance of isoprenoidal GDGTs, TEX86 values and other related indices for new and published Oligocene and Eocene sediments (n.b. the fractional abundance of isoprenoidal GDGTs was unavailable for IODP Site 1356). Values with yellow shading are excluded from the TEX86 compilation used in Fig. 7-9. Values with red text are those with a Red Sea-type GDGT distribution (i.e. GDGTRS >30 %) and may overestimate SST. Sheet 2: Each TEX86H time-series was grouped into low- (<30 degrees) or high-latitude (>55 degrees) bins and translated into a relative temperature (Δ SST) by comparison to the warmest temperature in that time series and fitted with a non-parametric LOESS regression. Sheet 3: Sequential removal of one data series at a time (jackknifing) within the low-latitude compilation. Sheet 4: Same as above but within the high-latitude compilation. Samples were collected from a range of globally-distributed marine sediments. Either collected via DSDP, ODP, IODP or personal sampling expeditions.
The data is presented as relative abundances of all species encountered in 300 counts on standard light microscope smear slides. Counts are presented from 64 samples, ranging from sample U1510A 48X 1W 50-51 cm (435.90 m) to U1510A 52X CC 24 cm (478.09 m). A second dataset provides semi-quantitative data from the same samples, which includes species that were not encountered during the 300 count.
Two datasets containing multiple diversity metrics of planktonic foraminifera. Recent data is from MARGO (Multiproxy approach for the reconstruction of the glacial ocean surface); Eocene data is from NEPTUNE (a relational database of microfossil occurrence records from DSDP and ODP publications), supplemented by literature searches. These data are related to Fenton et al (2016) Phil Trans (DOI: 10.1098/rstb.2015.0224) Data used in Fenton et al (2016) Environmental predictors of diversity in Recent planktonic foraminifera as recorded in marine sediments. The original data is from the MARGO database (Kucera, 2007)
A set of climatological annual and monthly sea surface temperature and 1.5m air temperature for the Eocene Epoch as run in HadCM3L. The data also relates to NERC Grant NE/I006281/1
The global carbon cycle - how much carbon is stored in its interconnected reservoirs (ocean, atmosphere, plants and soils on land, sediments in the deep sea) as well as the fluxes between them, is not set in stone. We know from the geological record that the concentration of CO2 in the atmosphere has varied enormously over the last few hundred million years. The chemistry of the oceans also gradually changes with time and the organisms living within it adjust and evolve. As a result, how the carbon cycle 'works', and particularly, how well (or not) atmospheric CO2 (and hence climate) is regulated in the face of disruption, also changes on geological time-scales. This creates challenges to understanding the causes and consequences of past global warming like events and how such events can be related to potential future changes. Sediments slowly accumulating in the deep ocean reflect what goes on around and above them, both chemically and biologically. Of particular interest to us is the mineral calcium carbonate (CaCO3), which can be found in the form of chalk and limestone rocks today. CaCO3 is used by certain marine organisms for constructing shells and skeletons. Hence, the amount of CaCO3 that in buried in sediments tells us something about ancient organisms and ecosystems. In addition, CaCO3 will start dissolving in seawater if the conditions too are acidic or the depth (and thus pressure) too great. How much CaCO3 originally created by organisms at the surface that escapes dissolution in sediments below to be buried and preserved in the geological record can thus tell us something about the chemistry, depth, and when data from many locations is available, the circulation of the ocean in the past. Looking for subtle changes in the composition of ancient mud in the hundreds and hundreds of meters of sediment core recovered from the ocean floor by drill ship would be a little like looking for a needle in a haystack. However, Nature has been kind to us and the transition from white-colored sediments rich in the carbonate shells of dead marine organisms to clays devoid of carbonate is easy to spot. This point represents a fine balance between the amount of shell material being deposited to the sediments and the rate of dissolution of these shells. Hence, this reflects a certain relationship between surface ocean biological processes and deep ocean chemistry and circulation. Any change in these factors will drive sediments rich in CaCO3 or devoid of any trace of carbonate secreting organisms. In this project we will compile the records from many hundreds of different sediment cores that have been recovered since the 1960s. Will identify the 'balance point' in these cores (if one exists) and combine all the confirmation to reconstruct how this balance point has changed in depth and time in the different ocean basins. Because the age of the sediments in some cores extends back to well before the white cliffs of Dover were deposited, we will start our record there. The interpretation of our curve will not be entirely straightforward, because multiple environmental influences all push and pull the balance point in different directions and with different strengths. We will therefore also use a computer model representation of the Earth's climate and oceans, its carbon cycle, ocean chemistry, and the composition of sediments in the deep sea. We will use this model to explore how the different aspects of the global carbon cycle affect the balance point, and by comparing model predictions to our new curve, interpret how the carbon cycling and the sensitivity of atmospheric pCO2 (and hence climate) to being perturbed by massive greenhouse gas release, has changed over the past 150 million years. Hence we will not only be able to answer the question: do we live in a particularly 'lucky' or 'unlucky' time in terms of how sensitive our global environment is burning fossil fuels, but we will know why.
Supplementary material for published paper, Early Paleogene wildfires in peat-forming environments at Schoningen, Germany by BE Robson et al, http://doi.org/10.1016/j.palaeo.2015.07.016 NERC grant abstract: Human activity has led to an increase in pCO2 and methane levels from pre-industrial times to today. While the former increase is primarily due to fossil fuel burning, the increase in methane concentrations is more complex, reflecting not only direct human activity but also feedback mechanisms in the climate system related to temperature and hydrology-induced changes in methane emissions. To unravel these complex relationships, scientists are increasingly interrogating ancient climate systems. Similarly, one of the major challenges in palaeoclimate research is understanding the role of methane biogeochemistry in governing the climate of ice-free, high-pCO2 greenhouse worlds, such as during the early Paleogene (around 50Ma). The lack of proxies for methane concentrations is problematic, as methane emissions from wetlands are governed by precipitation and temperature, such that they could act as important positive or negative feedbacks on climate. In fact, the only estimates for past methane levels (pCH4) arise from our climate-biogeochemistry simulations wherein GCMs have driven the Sheffield dynamic vegetation model, from which methane fluxes have been derived. These suggest that Paleogene pCH4 could have been almost 6x modern pre-industrial levels, and such values would have had a radiative forcing effect nearly equivalent to a doubling of pCO2, an impact that could have been particularly dramatic during time intervals when CO2 levels were already much higher than today's. Thus, an improved understanding of Paleogene pCH4 is crucial to understanding both how biogeochemical processes operate on a warmer Earth and understanding the climate of this important interval in Earth history. We propose to improve, expand and interrogate those model results using improved soil biogeochemistry algorithms, conducting model sensitivity experiments and comparing our results to proxy records for methane cycling in ancient wetlands. The former will provide a better, process-orientated understanding of biogenic trace gas emissions, particularly the emissions of CH4, NOx and N2O. The sensitivity experiments will focus on varying pCO2 levels and manipulation of atmospheric parameters that dictate cloud formation; together, these experiments will constrain the uncertainty in our trace greenhouse gas estimates. To qualitatively test these models, we will quantify lipid biomarkers and determine their carbon isotopic compositions to estimate the size of past methanogenic and methanotrophic populations, and compare them to modern mires and Holocene peat. The final component of our project will be the determination of how these elevated methane (and other trace gas) concentrations served as a positive feedback on global warming. In combination our work will test the hypothesis that elevated pCO2, continental temperatures and precipitation during the Eocene greenhouse caused increased wetland GHG emissions and atmospheric concentrations with a significant feedback on climate, missing from most modelling studies to date. This work is crucial to our understanding of greenhouse climates but such an integrated approach is not being conducted anywhere else in the world; here, it is being led by international experts in organic geochemistry, climate, vegetation and atmospheric modelling, and palaeobotany and coal petrology. It will represent a major step forward in our understanding of ancient biogeochemical cycles as well as their potential response to future global warming.
Carbon and oxygen isotopic composition of benthic foraminifera spanning the early and middle Eocene succession recovered from borehole 16/28-Sb01. For description of this sedimentary sequence see Haughton et al. 2005. Petroleum Geology: North-West Europe and Global Perspectives, Proceedings of the 6th Petroleum Geology Conference, 1077–1094.
Carbon and oxygen isotopic composition of planktic foraminifera spanning the early and middle Eocene succession recovered from borehole 16/28-Sb01. For description of this sedimentary sequence see Haughton et al. 2005. Petroleum Geology: North-West Europe and Global Perspectives, Proceedings of the 6th Petroleum Geology Conference, 1077–1094.
Carbon and oxygen isotopic composition of bulk sediment carbonate spanning the early and middle Eocene succession recovered from borehole 16/28-Sb01. For description of this sedimentary sequence see Haughton et al. 2005. Petroleum Geology: North-West Europe and Global Perspectives, Proceedings of the 6th Petroleum Geology Conference, 1077–1094.
These data were produced within the objectives of the NERC grant (alongside collaborator Gibbs at NOC, Southampton) and predominantly comprise biometric data collected under light microscope at x1500 magnification from the coccolithophore taxon Coccolithus pelagicus, a heavily calcified taxon with a long fossil record. The data was collected as part of a collaborative research effort bringing together the modern and fossil consortia within the UK Ocean Acidification research programme. The data are from batch culture experiments on both modern sub-species of C. pelagicus and provide cell size, coccosphere size, coccolith size and number of coccoliths per cell. The same parameters were measured from C. pelagicus from North Atlantic field and sediment trap samples from inside and outside bloom conditions. Again, the same parameters were also measured from C. pelagicus from exceptionally well-preserved fossil material from several shelf and off-shelf marine locations including New Jersey, Tanzania, California and the Bay of Biscay.