@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 { ISI:000481723500018,
	title = {The application of delta C-13, TOC and C/N geochemistry of mangrove sediments to reconstruct Holocene paleoenvironments and relative sea levels, Puerto Rico},
	journal = {MARINE GEOLOGY},
	volume = {415},
	year = {2019},
	month = {SEP},
	pages = {105963},
	abstract = {We assessed the use of delta C-13, TOC and C/N values of bulk sedimentary organic matter (OM) to reconstruct paleoenvironmental and relative sea-level change from mangrove environments in Puerto Rico. The modern distribution of delta C-13, TOC and C/N values was described from 63 vegetation and 59 surface sediment samples collected from three sites containing basin and riverine mangrove stands, and was compared to microfossil (foraminiferal and thecamoebian) assemblages. Four vertically-zoned environments were identified: tidal flat (delta C-13: -18.6 +/- 2.8 parts per thousand; TOC: 10.2 +/- 5.7\%; C/N: 12.7 +/- 3.1), mangrove (delta C-13: -26.4 +/- 1.0 parts per thousand; TOC: 33.9 +/- 13.4\%; C/N: 24.3 +/- 6.2), brackish transition (delta C-13: -28.8 +/- 0.7 parts per thousand; TOC: 40.8 +/- 11.7\%; C/N: 21.7 +/- 3.7), and freshwater swamp (delta C-13: -28.4 +/- 0.4 parts per thousand; TOC: 42.8 +/- 4.8\%; C/N: 17.0 +/- 1.1). These environments had distinct delta C-13, TOC and C/N values, with the exception of the brackish transition and freshwater swamp zones that were difficult to distinguish on a geochemical basis alone. The foraminiferal assemblages were complicated by a group that did not show a relationship to elevation due to the presence of calcareous foraminifera occurring above mean higher high water (MHHW), likely resulting from washover or transport by storms. However, the ratio of foraminifera to thecamoebians (F/T) along with delta C-13, TOC and C/N values refines the distinction between brackish and freshwater environments. Using linear discriminant analysis, we applied the delta C-13, TOC, C/N and F/T distributions to a 1.7 m core containing a continuous sequence of Rhizophora mangle peat, which began accumulating at similar to 1650-1930 CE. Together, microfossils, delta C-13, TOC, and C/N values, and the core chronology from Cs-137 and radiocarbon dating revealed that sediments in the core likely accumulated in response to anthropogenic sediment delivery, making it unsuitable for relative sea-level reconstruction. We caution that in the absence of detailed litho-, bio-, chemo-, or chrono-stratigraphic analyses as presented here, care should be taken in interpreting sea-level histories derived from single dates on mangrove peats.},
	issn = {0025-3227},
	doi = {10.1016/j.margeo.2019.105963},
	author = {Khan, Nicole S. and Vane, Christopher H. and Engelhart, Simon E. and Kendrick, Chris 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.}
}
@article {2816,
	title = {The role of sediment compaction and groundwater withdrawal in local sea-level rise, Sandy Hook, New Jersey, USA},
	journal = {Quaternary Science Reviews},
	volume = {181},
	year = {2018},
	month = {Jan-02-2018},
	pages = {30 - 42},
	abstract = {The rate of relative sea-level (RSL) rise at Sandy Hook, NJ (4.0 {\textpm} 0.5 mm/yr) was higher than The Battery, NY (3.0 {\textpm} 0.3 mm/yr) from 1900 to 2012 despite being separated by just 26 km. The difference cannot be explained by differential glacial isostatic adjustment (GIA; 1.4 {\textpm} 0.4 and 1.3 {\textpm} 0.4 mm/yr RSL rise, respectively) alone. We estimate the contribution of sediment compaction to subsidence at Sandy Hook using high-resolution grain size, percent organic matter, and porosity data from three upper Quaternary (<=13,350 cal yr) cores. The organic matter content (<2\%) is too low to contribute to local subsidence. However, numerical modeling of the grain size-depth-age-porosity relationship indicates that compaction of deglacial silts likely reduced the column thickness by 10{\textendash}20\% over the past 13,350 cal yrs. While compaction rates were high immediately after the main silt deposition (13,350{\textendash}13,150 cal yrs BP), rates decreased exponentially after deposition to an average 20th century rate of 0.16 mm/yr (90\% Confidence Interval (C.I.), 0.06{\textendash}0.32 mm/yr). The remaining \~{}0.7 mm/yr (90\% C.I. 0.3{\textendash}1.2 mm/yr) difference in subsidence between Sandy Hook and The Battery is likely due to anthropogenic groundwater withdrawal. Historical data from Fort Hancock wells (2 km to the southeast of the Sandy Hook tide gauge) and previous regional work show that local and regional water extraction lowered the water levels in the aquifers underlying Sandy Hook. We suggest that the modern order of contribution to subsidence (highest to lowest) appears to be GIA, local/regional groundwater extraction, and compaction of thick Quaternary silts.},
	keywords = {Marginal marine, North America, numerical modeling, Quaternary, Sea-level change, sedimentology},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2017.11.031},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379117303657},
	author = {Johnson, Christopher S. and Miller, Kenneth G. and Browning, James V. and Kopp, Robert E. and Khan, Nicole S. and Fan, Ying and Stanford, Scott D. and Horton, Benjamin P.}
}
