@article {3004,
	title = {Implications of Single-Step Graphitization For Reconstructing Late Holocene Relative Sea-Level Using Radiocarbon-Dated Organic Coastal Sediment},
	journal = {Radiocarbon},
	year = {2022},
	month = {08/2022},
	pages = {1 - 20},
	abstract = {Late Holocene relative sea-level reconstructions are commonly generated using proxies preserved in salt-marsh and mangrove sediment. These depositional environments provide abundant material for radiocarbon dating in the form of identifiable macrofossils (salt marshes) and bulk organic sediment (mangroves). We explore if single-step graphitization of these samples in preparation for radiocarbon dating can increase the number and temporal resolution of relative sea-level reconstructions without a corresponding increase in cost. Dating of salt-marsh macrofossils from the northeastern United States and bulk mangrove sediment from the Federated States of Micronesia indicates that single-step graphitization generates radiocarbon ages that are indistinguishable from replicates prepared using traditional graphitization, but with a modest increase in error (mean/maximum of 6.25/15 additional 14C yr for salt-marsh macrofossils). Low 12C currents measured on bulk mangrove sediment following single-step graphitization likely render them unreliable despite their apparent accuracy. Simulated chronologies for six salt-marsh cores indicate that having twice as many radiocarbon dates (since single-step graphitization costs \~{}50\% of traditional graphitization) results in narrower confidence intervals for sample age estimated by age-depth models when the additional error from the single-step method is less than \~{}50 14C yr (\~{}30 14C yr if the chronology also utilizes historical age markers). Since these thresholds are greater than our empirical estimates of the additional error, we conclude that adopting single-step graphitization for radiocarbon measurements on plant macrofossils is likely to increase precision of age-depth models by more than 20/10\% (without/with historical age markers). This improvement can be implemented without additional cost.},
	keywords = {age-depth model, mangrove, Massachusetts, Micronesia, Salt marsh},
	isbn = {0033-8222, 1945-5755},
	doi = {10.1017/RDC.2022.55},
	url = {https://www.cambridge.org/core/journals/radiocarbon/article/implications-of-singlestep-graphitization-for-reconstructing-late-holocene-relative-sealevel-using-radiocarbondated-organic-coastal-sediment/41F75E6A0679F0E659C96F438452D64C},
	author = {Sefton, Juliet P. and Kemp, Andrew C. and Elder, Kathryn L. and Hansman, Roberta L. and Roberts, Mark L.}
}
@article {khan_relative_2022,
	title = {Relative sea-level change in South Florida during the past ~5000~years},
	journal = {Global and Planetary Change},
	volume = {216},
	year = {2022},
	month = {09/2022},
	pages = {103902},
	abstract = {A paucity of detailed relative sea-level (RSL) reconstructions from low latitudes hinders efforts to understand the global, regional, and local processes that cause RSL change. We reconstruct RSL change during the past ~5~ka using cores of mangrove peat at two sites (Snipe Key and Swan Key) in the Florida Keys. Remote sensing and field surveys established the relationship between peat-forming mangroves and tidal elevation in South Florida. Core chronologies are developed from age-depth models applied to 72 radiocarbon dates (39 mangrove wood macrofossils and 33 fine-fraction bulk peat). RSL rose 3.7~m at Snipe Key and 5.0~m at Swan Key in the past 5~ka, with both sites recording the fastest century-scale rate of RSL rise since ~1900~CE (~2.1~mm/a). We demonstrate that it is feasible to produce near-continuous reconstructions of RSL from mangrove peat in regions with a microtidal regime and accommodation space created by millennial-scale RSL rise. Decomposition of RSL trends from a network of reconstructions across South Florida using a spatio-temporal model suggests that Snipe Key was representative of regional RSL trends, but Swan Key was influenced by an additional local-scale process acting over at least the past five millennia. Geotechnical analysis of modern and buried mangrove peat indicates that sediment compaction is not the local-scale process responsible for the exaggerated RSL rise at Swan Key. The substantial difference in RSL between two nearby sites highlights the critical need for within-region replication of RSL reconstructions to avoid misattribution of sea-level trends, which could also have implications for geophysical modeling studies using RSL data for model tuning and validation.},
	keywords = {Holocene, mangrove, Proxy reconstruction, Reproducibility, sea level},
	issn = {0921-8181},
	doi = {10.1016/j.gloplacha.2022.103902},
	url = {https://www.sciencedirect.com/science/article/pii/S0921818122001692},
	author = {Khan, Nicole S. and Ashe, Erica and Moyer, Ryan P. and Kemp, Andrew C. and Engelhart, Simon E. and Brain, Matthew J. and Toth, Lauren T. and Chappel, Amanda and Christie, Margaret and Kopp, Robert E. and Horton, Benjamin P.}
}
@article {2774,
	title = {Testing the Utility of Geochemical Proxies to Reconstruct Holocene Coastal Environments and Relative Sea Level: A Case Study from Hungry Bay, Bermuda},
	journal = {Open Quaternary},
	volume = {5},
	year = {2019},
	month = {May-02-2019},
	abstract = {On low-lying, tropical and sub-tropical coastlines freshwater marshes may be replaced by salt-tolerant mangroves in response to relative sea-level rise. Pollen analysis of radiocarbon-dated sediment cores showed that such a change occurred in Hungry Bay, Bermuda during the late Holocene. This well-established paleoenvironmental trajectory provides an opportunity to explore if geochemical proxies (bulk-sediment δ13C and Rock-Eval pyrolysis) can reconstruct known environmental changes and relative sea level. We characterized surface sediment from depositional environments in Bermuda (freshwater wetlands, saline mangroves, and wrack composed of Sargassum natans macroalgae) using geochemical measurements and demonstrate that a multi-proxy approach can objectively distinguish among these environments. However, application of these techniques to the transgressive sediment succession beneath Hungry Bay suggests that freshwater peat and mangrove peat cannot be reliably distinguished in the sedimentary record, possibly because of post-depositional convergence of geochemical characteristics on decadal to multi-century timescales and/or the relatively small number of modern samples analyzed. Sediment that includes substantial contributions from Sargassum is readily identified by geochemistry, but has a limited spatial extent. Radiocarbon dating indicates that beginning at {\textendash}700 CE, episodic marine incursions into Hungry Bay (e.g., during storms) carried Sargassum that accumulated as wrack and thickened through repeated depositional events until ~300 CE. It took a further ~550 years for a peat-forming mangrove community to colonize Hungry Bay, which then accumulated sediment rapidly, but likely out of equilibrium with regional relative sea-level rise.},
	keywords = {mangrove, radiocarbon, Rock-Eval pyrolysis, Sargassum, δ13C},
	doi = {10.5334/oq.49},
	url = {http://www.openquaternary.com/articles/10.5334/oq.49/},
	author = {Kemp, Andrew C. and Vane, Christopher H. and Khan, Nicole S. and Ellison, Joanna C. and Engelhart, Simon E. and Horton, Benjamin P. and Nikitina, Daria and Smith, Struan R. and Rodrigues, Lisa J. and Moyer, Ryan P.}
}
