Techniques and applications of plant macrofossil analysisin sea‐level studies

Waller, Martyn

doi:10.1002/9781118452547.ch12

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…The ratio of stable carbon isotopes (δ 13 C) in bulk sediment, therefore, reflects the dominant vegetation community at the time of deposition and can be used to verify or constrain estimates of PME made by transfer functions because plant communities on salt marshes are also sea-level indicators (e.g. Johnson et al, 2007; Kemp et al, 2012b; Shennan, 1986; Waller, 2015). On the US mid-Atlantic and northeast coasts, the MHHW tidal datum is the boundary between communities of salt-marsh plants dominated by C 3 (e.g.…”

Section: Methodsmentioning

confidence: 99%

Relative sea-level trends in New York City during the past 1500 years

et al. 2017

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foraminifera, salt marsh, Bayesian transfer function, carbon isotope, The Bronx, sedimentation Abstract: New York City is at risk from 21st century relative sea-level rise because it is likely to experience a regional trend that exceeds the global mean and has high concentrations of low-lying infrastructure and socio economic activity. To provide a long-term context for anticipated future trends, we reconstructed relative sea-level change during the past ~1500 years using a sediment core from a salt marsh at Pelham Bay in The Bronx. Foraminifera and bulk sediment δ13C values were used as sea level indicators, while the history of sediment accumulation was established by radiocarbon dating of plant macrofossils 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 comprised of three modules (calibration, chronology, and process) to accommodate multiple proxies and to provide a unified statistical framework for quantifying uncertainty. We show that relative sea level in New York City rose by ~1.70 m since ~575 CE, of which ~0.38 m occurred after 1850 CE. The rate of relative sea level rise increased markedly between 1852 CE and 1911 CE, which coincides with other reconstructions along the U.S. Atlantic coast. A regional tidal model was used to investigate the possible influence of tidal-range change in Long Island Sound on our reconstruction and we demonstrate that this effect was likely small. However, future tidal-range change could http://mc.manuscriptcentral.com/holocene approximately mean high water (MHW) and mean higher high water (MHHW; e.g., van de Plassche, 1991;Redfield, 1972; Johnson and York, 1915). At the boundary between the salt marsh and surrounding, upland forest is a narrow vegetative zone dominated by Phragmites australis. This zone is found above the MHHW tidal datum. Peat forming in this environment is typically a black, amorphous organic matrix that hosts the rhizomes of Phragmites australis plants (e.g., Niering et al., 1977). Through time these rhizomes are commonly flattened and degraded, resulting in a homogenized peat. The halotype of Phragmites found on and around modern salt marshes in the northeastern United States is invasive, although native haloptypes existed prior to European colonization in this region (Saltonstall, 2002). Elsewhere this uppermost zone of marine influence may also be occupied by Schoeneplectus spp., Typha spp., and/or Iva fructescens. We estimated the great diurnal tidal range (mean lower low water, MLLW to MHHW) at the site to be 2.44 m using the VDatum Harbor and Long Island Sound. METHODS Core collection and levelingThe sediment beneath the Pelham Bay salt marsh was described from hand-driven cores collected along two transects ( Figure 1C, D). Core PBA-4 was selected for detailed analysis because it included the thickest accumulation of peat and was therefore anticipated to provide the longest RSL record and adequate materia...

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Section: Methodsmentioning

confidence: 99%

Relative sea-level trends in New York City during the past 1500 years

et al. 2017

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“…The reconstruction is produced by measuring the elevation of a paleo sea-level indicator in the field with respect to a modern tidal datum such as mean tide level. Sea-level indicators are physical, chemical, or biological proxies with a systematic and quantifiable relationship to contemporary tides (e.g., [92,99]) and include geomorphic features (e.g., [69]), coral reefs (e.g., [24]), coral microatolls (e.g., [108]), and saltmarsh plants (e.g., [103]) or micro-organisms (e.g., [41]). Each type of indicator forms or accumulates at a particular range of elevations that is termed the indicative range and that can be established by direct measurement of modern analogs (e.g., [109]).…”

Section: Relative and Global Mean Sea Levelmentioning

confidence: 99%

Paleo Constraints on Future Sea-Level Rise

Kemp

Dutton

Raymo

2015

Curr Clim Change Rep

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Sea-level rise predicted for the twenty-first century and beyond will become increasingly hazardous to coastal populations, economies, static infrastructure, and ecosystems. Accurately predicting the magnitude and rate of future sealevel rise at local, regional, and global scales is necessary to effectively plan for and manage this growing hazard. Sea-level reconstructions show how high and how fast sea level rose when Earth's climate regime was similar to that anticipated in the immediate future. We draw upon examples from the past three million years, including the Pliocene (∼3 million years ago), the Last Interglacial period (Marine Isotope Stage 5e, ∼125,000 years ago), and the Common Era (last ∼2000 years) to provide a synopsis of what is known about sea-level rise during these past warm periods and highlight some of the benefits and challenges of using paleo sealevel data to predict future changes.

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“…Several high-resolution records of sea level change over the last few thousand years have been reconstructed using sediment cores from salt marshes (e.g., Gehrels et al 2005;Kemp et al 2011;Waller 2015). This technique relies on looking at the assemblages of foraminifera, which allows us to constrain the vertical position of sea level based on the presence and absence of the various foraminiferal taxa.…”

Section: Sea Level Changes Over the Past Few Millenniamentioning

confidence: 99%

Sea Level Rise

Mitchum¹,

Dutton²,

Chambers³

et al. 2017

Florida’s Climate: Changes, Variations, &Amp; Impacts

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Sea level rise is naturally a topic of concern to many Floridians. Our intention in this chapter is to give the reader enough information on this topic to inform decisions Key Messages• Unless greenhouse gas emissions are reduced, sea level will most likely increase by 1-2 meters over the next 50 to 100 years. The time scale is not certain, but the ultimate rise of sea level is. The only way to mitigate this risk is to reduce greenhouse gas emissions as soon as possible and to commit to lowered emissions in the future.• The linkage between greenhouse emissions and sea level rise in incontrovertible. Sea level rise projections are often misinterpreted due a lack of understanding of this point. We cannot invoke any particular sea level rise projection without committing to the emission scenario associated with that sea level rise projection. The scatter seen in charts projecting sea level rise is due to the differing emission scenarios assumed, and is not due to uncertainty in the climate science that underlies the projections.• On shorter time scales of a few years to a few decades, sea level rise fluctuations due to oceanic and atmospheric changes and vertical land motion can substantially increase the frequency of nuisance flooding events. Although these smaller sea level changes are likely ephemeral, these events can have large economic impacts.• Sea level rise impacts in coming decades will be felt differently in different communities. Regional to local adaptations should be developed based on the best available science, and to support these efforts, scientists need to be involved at the local level. We do not discuss this point in our chapter, but would argue that an important outcome of this book is that local scientists, practitioners, and decision makers will have the information needed to inform at the local level.

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Techniques and applications of plant macrofossil analysisin sea‐level studies

Cited by 3 publications

References 21 publications

Relative sea-level trends in New York City during the past 1500 years

Relative sea-level trends in New York City during the past 1500 years

Paleo Constraints on Future Sea-Level Rise

Sea Level Rise

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