The response of coral reefs to rapid environmental change and the use of reef records in past sea-level reconstructions

This thesis addresses the overarching question: how do coral reefs respond to and record geologically rapid sea-level and environmental change? To answer this, the environmental controls on reef development and demise are investigated. Specifically, the conditions leading to reef drowning, the controls on reef re-initiation, and patterns of reef development under sea-level fluctuations are examined at chosen study sites. Three case studies represent distinct geologic and temporal Indo-Pacific reef settings, and through a consistent approach integrating geochronology, sedimentology, and geomorphology, reef development and past environment are analyzed. First, the drowning of a rapidly subsiding Hawaiian reef terrace in response to deglacial sea-level rise is analyzed. This provides improved temporal constraints on meltwater pulse-1A (14.75 ka), and analysis of the conditions leading to reef drowning and backstepping. Second, a new growth model for the Holocene initiation of One Tree Reef (Great Barrier Reef) from ~8.2 ka is presented from new high-resolution geochronology and paleoecology. Corresponding geochemical data from coral skeletal-bound organic nitrogen (δ15N) is reported; combined these studies reveal a growth phase from 87 ka characterized by slower, deeper and more sediment-tolerant reef builders coeval with elevated terrigenous nutrient levels. Third, multiple stages of reef development under Marine Isotope Stage 5 (~130-100 ka) sea-level rise and fall in Western Australia are examined. Based on open-system U-Th ages, sedimentology and paleoecology from an accommodation-limited reef terrace, there is evidence for a MIS 5e sea-level oscillation and peak of +3.2 m, and MIS 5c reef growth identified here for the first time following a sea-level drop of >26 m (up to -18 m deep). These case studies contribute to a globally-applicable framework for understanding factors contributing to reef resilience or vulnerability under changing environmental conditions

Relative Sea-Level Trends in New York City During the Past 1500 Years

New York City (NYC) is threatened by 21st-century relative sea-level (RSL) rise because it will experience a trend that exceeds the global mean and has high concentrations of low-lying infrastructure and socioeconomic activity. To provide a long-term context for anticipated trends, we reconstructed RSL change during the past ~1500 years using a core of salt-marsh sediment from Pelham Bay in The Bronx. Foraminifera and bulk-sediment δ13C values were used as sea-level indicators. The history of sediment accumulation was established by radiocarbon dating and recognition of pollution and land-use trends of known age in down-core elemental, isotopic, and pollen profiles. The reconstruction was generated within a Bayesian hierarchical model to accommodate multiple proxies and to provide a unified statistical framework for quantifying uncertainty. We show that RSL in NYC rose by ~1.70 m since ~575 CE (including ~0.38 m since 1850 CE). The rate of RSL rise increased markedly at 1812–1913 CE from ~1.0 to ~2.5 mm/yr, which coincides with other reconstructions along the US Atlantic coast. We investigated the possible influence of tidal-range change in Long Island Sound on our reconstruction using a regional tidal model, and we demonstrate that this effect was likely small. However, future tidal-range change could exacerbate the impacts of RSL rise in communities bordering Long Island Sound. The current rate of RSL rise is the fastest that NYC has experienced for \u3e1500 years, and its ongoing acceleration suggests that projections of 21st-century local RSL rise will be realized

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Early Chapman, Dickinson County

Kelsey Sanborn, “Early Chapman, Dickinson County,” Chapman Center Research Collections, https://ccrsresearchcollections.omeka.net/items/show/122.This study of early Chapman and the Sanborn Lumber Yard in Dickinson County, Kansas, includes a map of the county, an interview, and photographs of the Sanborn Lumber Yard

Holocene microbialite geochemistry records > 6000 years of secular influence of terrigenous flux on water quality for the southern Great Barrier Reef

Anthropocene climate change and water quality degradation represent unprecedented challenges to modern coral reefs. Although declining reef health after European colonization is well documented around the world and increased terrigenous sediment flux is known to have terminated deglacial reefs in the Great Barrier Reef (GBR), longer-term patterns of water quality are poorly understood. Here we present the first direct proxy-based Holocene water quality reconstruction for any reef. The unique geochronological framework provided by cores from Heron and One Tree reefs (offshore, southern GBR) allowed reconstruction of offshore water quality from 8200 to 1800 years before present (BP) using centennially resolved microbialite-based geochemical proxies. Terrigenous sediment-sourced trace elements were measured in microbialites from a well dated succession of reef rock and in paleosol (ancient soil) formed at the Pleistocene-Holocene unconformity. Microbialite-hosted rare earth element and yttrium distributions (e.g., Nd/YbSN = 0.36; Y/Ho = 57) are consistent with precipitation from shallow oxygenated seawater but show a non-linear trend through the Holocene with distinct intervals of higher and lower terrigenous influence relative to average values. Immediately following reef initiation (>8300 years ago) our data suggest increasing terrigenous influence by 8000 ka. Surrounding reef seawater became less affected by terrigenous runoff from ~7000 years ago, but showed marked mid-Holocene variability related to regional climatic factors. Major fluctuations between intervals of high and low relative terrigenous influence correlate well with particular regional and more global climate records. These include local relative sea level fluctuations, fluctuations in Indian-Australian Summer Monsoon (IASM) strength, and dampened El Niño Southern Oscillation (ENSO) frequency corresponding to greater terrigenous influence in the southern GBR at ~7.0, 5.4, and 2.7 ka BP. Water quality then improved significantly after 3200 years BP. More broadly, it is well established that water quality has a major effect on reefs and reef communities, but for past reef history, inferences about water quality are commonly highly speculative. Reefal microbialite geochemistry provides an independent, high-quality proxy for ambient water quality that can be used to directly compare contemporaneous reef growth dynamics and ecological shifts to changing water quality. The high concentrations of trace elements in reefal microbialites, relative to other marine carbonates, provide a very robust, if time averaged, proxy for investigating ancient seawater chemistry, even in offshore reefs, such as Heron Reef. At the same time, the proxy provides a new independent data set for that may aid interpretation and model of climate change relevant to reef growth at centennial to millennial scales. As reefal microbialites are common in many global reef systems, where associated with high quality dating, they may provide useful proxies for investigating secular changes in water quality and associated climatic drivers at various temporal scales in other regions of the world.</p

High-resolution hyperspectral imaging of diagenesis and clays in fossil coral reef material: a nondestructive tool for improving environmental and climate reconstructions

Hyperspectral imagery (1000–2500 nm) was used to quantitatively map carbonate and clay minerals in fossil reef cores that are relevant to accurately reconstructing past environmental and climatic conditions. Techniques were developed using hyperspectral imagery of fossil reef corals and cores acquired from three different geological settings, and were validated against independent measures of calcite to aragonite ratios. Aragonite, calcite, and dolomite were distinguished using a combination of the wavelength position and asymmetry of the primary carbonate absorption between 2300 and 2350 nm. Areas of core containing small amounts of calcite (>2–5%) were distinguished from aragonite in imagery of two cores, enabling quantitative maps of these minerals to be constructed. Dolomite was found to be the dominant mineral in another core. Trace amounts of the aluminium-rich clay mineral kaolinite were detected, quantified, and mapped in one core using its diagnostic absorption feature near 2200 nm. The amounts of clay detected from hyperspectral imagery were below the limits of detection by standard X-ray diffraction techniques but its presence was confirmed by Fourier Transform Infrared Spectroscopy. Hyperspectral imagery acquired at high spatial resolution simplifies vetting procedures for secondary carbonate minerals in coral reef cores, significantly reduces sampling time and costs, and is a powerful nondestructive tool to identify well-preserved coral aragonite in cores for uses in paleoclimate, paleoenvironment and paleoecosystem reconstruction

Holocene reef growth in the tropical southwestern Atlantic: Evidence for sea level and climate instability

The Holocene epoch offers a potential analogue for understanding future sea-level variability as both SST's and Global Mean Sea Levels (GMSL) were at times higher than observed today. However, GMSL can differ significantly from Relative Sea Level (RSL), even at far-field sites remote from margins of former ice sheets. Much of this spatial variability has been shown to be consistent with the predictions of glacial isostatic adjustment (GIA) models. Whilst it is generally accepted that RSL at far-field sites reached its maximum during the mid-Holocene, there have been many interpretations of sea level fall following the highstand from ∼6 ka. Here, we present a RSL history from several tectonically stable, far-field sites in eastern Brazil, derived from 17 microatoll and 45 fossil reef flat ages. Our results show evidence for two periods of RSL instability during the Holocene which differ from GIA predictions, including a hiatus in reef growth ∼3.7–2.5 ka. These results are broadly synchronous with several other locations in the Southern Hemisphere suggesting global rather than regional climatic forcing mechanisms are responsible. Variations in SST and southern hemisphere ice sheet dynamics are proposed as possible controlling mechanisms for the observed RSL oscillations beginning at ∼3.7 ka and 2 ka respectively. We suggest that these global processes combined with increased precipitation (and higher sediment flux) from several regional climatic forces created inhospitable conditions for reef growth, contributing to the observed hiatus and reduced reef flat accretion during the late Holocene (∼2 ka to present).</p

New evidence of Hawaiian coral reef drowning in response to meltwater pulse-1A

Fossil coral reefs are valuable recorders of glacio-eustatic sea-level changes, as they provide key temporal information on deglacial meltwater pulses (MWPs). The timing, rate, magnitude, and meltwater source of these sea-level episodes remain controversial, despite their importance for understanding ocean-ice sheet dynamics during periods of abrupt climatic change. This study revisits the west coast of the Big Island of Hawaii to investigate the timing of the −150 m H1d terrace drowning off Kawaihae in response to MWP-1A. We present eight new calibrated 14C-AMS ages, which constrain the timing of terrace drowning to at or after 14.75 + 0.33/-0.42 kyr BP, coeval with the age of reef drowning at Kealakekua Bay (U-Th age 14.72 ± 0.10 kyr BP), 70 kms south along the west coast. Integrating the chronology with high-resolution bathymetry and backscatter data, detailed sedimentological analysis, and paleoenvironmental interpretation, we conclude the H1d terrace drowned at the same time along the west coast of Hawaii in response to MWP-1A. The timing of H1d reef drowning is within the reported uncertainty of the timing of MWP-1A interpreted from the IODP Expedition 310 Tahitian reef record. © 2017 Elsevier LtdAustralian Research Council-DP1094001, DP120101793, NSF-OCE-1559040, and Japan Society for the Promotion of -JP15KK0151 and 17H0116

Environmental controls on holocene reef development along the eastern brazilian margin

Drilling of the eastern Brazilian continental shelf in the 1980’s identified several main factors controlling Holocene reef growth in the South Atlantic. However, this model is limited by few fossil reef cores, sparse uncalibrated dates (14-AMS ages with newly defined coralgal assemblages, sedimentary facies and lateral progradation rates from several transects in the Abrolhos Continental Shelf (ACS) and Anchieta reef, Eastern Brazil. The progression of reef flat development across the ACS reefs varies through time, influencing the timing at which each reef shifts from a juvenile to senile state. This has produced a range of reef evolutionary states not previously identified in the South Atlantic. This difference in timing is likely controlled by: (1) the availability of antecedent substrate and (2) inimical conditions created during the initial transgression ~ 8–10 thousands of years ago (ka), causing spatial and temporal delays in reef turn on. We suggest that weak hydrodynamic energy and unique mushroom-shaped morphology of the ACS reefs are responsible for the lack of discernible progradation direction, whilst high sedimentation and increased tolerance to adverse conditions produced the rapid progradation rates (762.5–1909 m/ky). Finally, following a reef flat hiatus from ~ 3.7–2.5 ka we show a distinct shift in the dominant reef assemblage from Mussissmilia to more stress-tolerant Siderastrea in the ACS reefs, as well as declining reef growth at Anchieta. Falling sea levels combined with increased precipitation and higher sediment flux from regional climatic mechanisms likely created inimical conditions responsible for the observed shifts. Our results demonstrate that even though the health of these reefs has fluctuated through cycles independent of anthropogenic impacts, they are particularly sensitive to deteriorating water quality, as is currently observed due to large-scale deforestation, industrial uses, and recent mining disasters in the region.</p