Climate variability over the circum-Caribbean region during the past 1200 years from oxygen-isotope analyses of lake sediments
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Geography
Abstract
Variations in water availability, especially drought, on timescales of years to decades are a major concern for society. Changes in the frequency and magnitude of drought on such timescales are a likely outcome of future climate change, especially in subtropical regions. The area that encompasses the eastern part of Central America, the Gulf of Mexico and the Caribbean (hereafter the circum-Caribbean region) is likely to be especially sensitive to climate change in the future, especially in terms of the incidence and severity of drought: it is this region that is the subject of our proposed research. Meteorological records of rainfall are too short to encompass the full range of variations in past rainfall on timescales of years to decades or to indicate whether geographical patterns have changed through time and under different conditions. Natural 'archives' of past climate, including lake and marine sediments, speleothems (cave deposits) and tree rings, provide an opportunity to extend the meteorological records further back into the past and to shed light on the modes and causes of rainfall variability. In this research, we will investigate changes in rainfall over the past 1200 years using oxygen-isotope analyses of the calcite shells of ostracods preserved in lake sediments. We plan to analyse lake sediment cores that have already been collected from sites in the Yucatan Peninsula of eastern Mexico, Jamaica, Haiti and Barbuda. These sites are located on a west to east transect, along which changes in rainfall are known to have occurred over recent decades. Our reconstructions will be complemented by existing studies along a north to south transect within the circum-Caribbean region, thus allowing us to investigate changes in the geographical patterns of past rainfall. The past 1200 years is an important time period to study as it covers intervals of marked change in climate including the Medieval Climate Anomaly (MCA) of predominantly wet climate, the drier little ice age (LIA) and the terminal classic period of marked drought at the end of the MCA, which is thought to have contributed to major societal change in the Yucatan Peninsula. The broad variations in climate over this interval are quite well known, but changes in the geographical patterns in the region, despite being implied by existing data, are poorly constrained. Furthermore, links to potential causes, such as variations in ocean circulation and sea-surface temperatures, changes in solar activity and volcanic eruptions, are not well understood. By generating new reconstructions of variability in rainfall over the past 1200 years, we will provide further insights in to the nature and causes of change during this period. By extending the timespan of records beyond that of meteorological data, we will be able to show whether geographical patterns of rainfall variability have remained constant over the recent past or, as seems likely, have changed. In addition to providing important palaeoclimatic data for the circum-Caribbean region, our research will generate much-needed reconstructions of climate for archaeologists, especially those working on links between climate and society in Mexico and Barbuda.
Planned Impact
We have identified the following beneficiaries of the research described in this proposal.
1. State governments and government agencies. In Mexico, these include the governments of the States of Quintana Roo and Yucatan, which will be accessed via Universidad Autónoma de Yucatán (UADY) and ECOSUR (Centro de Investigaciones Ecologicas del Sureste). In Jamaica, the Ministry of Land, Water, Environment and Climate Change, the Water Resources Authority and the Jamaican Meteorological Office have expressed interest in our potential findings.
2. Schools and 6th form colleges in the UK and Jamaica. We have identified a number these who would welcome talks, presentations and workshops on the board themes addressed in our proposal. The precise subject matter and mode of delivery will depend on the age group of the audience, but will include general talks on climate and society to younger (e.g. UK year 6) pupils and seminars on palaeodata to High School and 6th form students. Target schools/colleges in the UK include Esher College, Hinchley Wood School and 6th Form College, Thames Ditton Junior School (all Surrey) and in Jamaica Meadowbrook High School, Wolmer's Boys and Wolmer's Girls schools, Jamaica College (all Kingston area).
1. State governments and government agencies. In Mexico, these include the governments of the States of Quintana Roo and Yucatan, which will be accessed via Universidad Autónoma de Yucatán (UADY) and ECOSUR (Centro de Investigaciones Ecologicas del Sureste). In Jamaica, the Ministry of Land, Water, Environment and Climate Change, the Water Resources Authority and the Jamaican Meteorological Office have expressed interest in our potential findings.
2. Schools and 6th form colleges in the UK and Jamaica. We have identified a number these who would welcome talks, presentations and workshops on the board themes addressed in our proposal. The precise subject matter and mode of delivery will depend on the age group of the audience, but will include general talks on climate and society to younger (e.g. UK year 6) pupils and seminars on palaeodata to High School and 6th form students. Target schools/colleges in the UK include Esher College, Hinchley Wood School and 6th Form College, Thames Ditton Junior School (all Surrey) and in Jamaica Meadowbrook High School, Wolmer's Boys and Wolmer's Girls schools, Jamaica College (all Kingston area).
Organisations
- University of Nottingham (Lead Research Organisation)
- University of Florida (Collaboration)
- ABERYSTWYTH UNIVERSITY (Collaboration)
- University of North Carolina at Chapel Hill (Collaboration)
- Natural Environment Research Council (Collaboration)
- University of Tennessee (Collaboration)
- UNIVERSITY OF EXETER (Collaboration)
People |
ORCID iD |
Sarah Elizabeth Metcalfe (Principal Investigator) |
Publications
Metcalfe S E
(2019)
Coherence from complexity? Maya lowland records of hydroclimate and human impact
Metcalfe S
(2022)
Response of a low elevation carbonate lake in the Yucatan Peninsula (Mexico) to climatic and human forcings
in Quaternary Science Reviews
Holmes J
(2023)
An 1800-year oxygen-isotope record of short- and long-term hydroclimate variability in the northern neotropics from a Jamaican marl lake
in Quaternary Science Reviews
Title | Future Memories art exhibition |
Description | Future Memories was an exhibition by artist Josefina Nelimarka held at SPACE Art + Technology, London, April 2019. Jonathan Holmes (overall project PI) acted as a consultant to this exhibition. |
Type Of Art | Artistic/Creative Exhibition |
Year Produced | 2019 |
Impact | The exhibition engaged non-scientists interactively in climate change issues. |
URL | https://spacestudios.org.uk/art-technology/interview-with-josefina-nelimarkka/ |
Description | Monitoring of Yaal Chac since 2009 confirms that it is highly evaporated and effectively closed, in spite of being called a 'cenote' which would imply a free connection to the regional groundwater. Monitoring of Freshwater Pond and Wallywash Great Pond confirms that these lakes are also influenced by evaporative enrichment. The monitoring data therefore confirm our original assumption that the lake-sediment oxygen-isotope records are proxies for changing effective moisture. The oxygen-isotope records from lake sediments show large and systematic changes over the course of the records. In low latitude lakes such as the ones in our study, time series of oxygen-isotopes in lacustrine carbonates are controlled primarily by the isotopic composition of lake water, which in turn is determined by the degree of evaporative concentration and ultimately effective rainfall. Our data from Freshwater Pond, Barbuda, provide a record that covers the period from the 16th century to present. Episodes of strong El Niño-like activity that occurred during the 18th, early 19th and late 20th centuries were associated with inferred drier conditions in Barbuda whereas inferred wetter periods in the late 18th and the late 19th century correspond with La Niña-like conditions. Further dating of the Yaal Chac core YC2011 sequence has shown that there is no hardwater effect influencing the most recent sediments (NERC Radiocarbon allocation1724.0713), but may have been more significant earlier in the record with an offset of 471 years recorded between bulk sediment and plant macrofossil ages at 389 cm (NERC Radiocarbon 1943.1015).Dating now confirms that the core sequence covers much of the Holocene. The downcore d18O record indicates reduced evaporative concentration in the mid Holocene, with two major drying events since 471 ± 37 yr BP. Data from Wallywash Great Pond also show marked variability, which we interpret to represent shifts in effective moisture. However, until the age models for these sites have been fully developed (see below), the synchronicity or lack thereof between changes in Jamaica and the other sites will remain unclear. Further scrutiny of sediments from Wallywash Great Pond revealed several levels that contained what appeared to be datable plant macrofossils. These have been dated at the NERC RCL, East Kilbride. Although the age-depth relationship is not perfect and further work will be required in order to develop a robust chronology for this site, we are now optimistic that this will ultimately be achievable. Attempts to date the sediments using U/Th we not successful although analysis of tephra, which is still ongoing, holds some promise. Further analysis of the Yaal Chac sequence, through comparison with other cores from the same location, revealed that there was a small gap in the sediment sequence. This has been filled by splicing in a segment of core collected at a later date with the addition of new data including XRF core scanning and isotope data. |
Exploitation Route | Once the age models have been fully developed, our time series of oxygen-isotope analyses will be of interest to others working on the palaeoclimate of the northern neotropics, to archaeologists working in this region and to climate modellers. |
Sectors | Environment |
Description | Some of the data from the project have fed into undergraduate and postgraduate teaching, including field-based teaching, at UCL and the University of Nottingham. The Pi from the project has also been a consultant on an exhibition (see notes in return) to improve public awareness of climate change. |
First Year Of Impact | 2015 |
Sector | Education,Culture, Heritage, Museums and Collections |
Description | Envision DTP |
Amount | £71,257 (GBP) |
Funding ID | NE/L002604/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 10/2014 |
End | 04/2018 |
Description | Isotope hydrology of the Yucatan Peninsula |
Amount | £23,000 (GBP) |
Funding ID | IP-1812-0618 |
Organisation | Natural Environment Research Council |
Department | NERC Isotope Geosciences Laboratory |
Sector | Academic/University |
Country | United Kingdom |
Start | 07/2018 |
End | 06/2020 |
Description | NERC Isoptope Geosciences Facilities Steering Group |
Amount | £7,500 (GBP) |
Funding ID | IP-1394-1113 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 02/2014 |
End | 02/2015 |
Description | NERC Isotope Geosciences Laboratory |
Amount | £29,200 (GBP) |
Funding ID | IP-1671-1116 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 11/2016 |
End | 07/2017 |
Description | Research Programme Grant 'Integrated ClimAte Resilience UnderStanding (ICARUS) Belize' |
Amount | £499,688 (GBP) |
Funding ID | RPG-2021-288 |
Organisation | The Leverhulme Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 02/2022 |
End | 01/2025 |
Title | Ostracod carbonate isotope data, Freshwater Pond, Barbuda |
Description | Ostracod carbonate isotope data, Freshwater Pond, Barbuda supplied to database held at National Geoscience Data Centre - British Geological Survey. |
Type Of Material | Database/Collection of data |
Provided To Others? | No |
Impact | None yet. |
Title | Water isotope data from Barbuda |
Description | Water isotope data from Freshwater Pond (lake), nearby groundwater and local precipitation. Supplied to database held at National Geoscience Data Centre - British Geological Survey |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | No |
Impact | None yet |
Title | Water isotope data from Jamaica |
Description | Water isotope data from Wallywash Great Pond (lake), nearby groundwater and local precipitation. Supplied to database held at National Geoscience Data Centre - British Geological Survey |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | No |
Impact | None yet |
Title | Water isotope data from Mexico |
Description | Water isotope data from Yaal Chac (lake), nearby groundwater and local precipitation. Supplied to database held at National Geoscience Data Centre - British Geological Survey |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | No |
Impact | None yet |
Description | Carbonate deposition in lowland lakes |
Organisation | University of Florida |
Department | College of Liberal Arts and Sciences |
Country | United States |
Sector | Academic/University |
PI Contribution | Invitation to contribute to conference presentation, plans for research grant application. |
Collaborator Contribution | Collaborative work on understanding the timing and nature of carbonate deposition in lowland lakes of the Maya region. |
Impact | Conference abstract and presentation at 2018 IAP meeting |
Start Year | 2018 |
Description | Radiocarbon age modelling of lake-sediment core BFWP |
Organisation | Natural Environment Research Council |
Department | NERC Radiocarbon Facility (Environment) |
Country | United Kingdom |
Sector | Charity/Non Profit |
PI Contribution | Collaboration with Dr Malu Cisneros-Dozal, NERC Radiocarbon Facility, East Kilbride, on age modelling of the lakesediment core BFWP from Freshwater Pond, Barbuda |
Collaborator Contribution | Radiocarbon age modelling of lake-sediment core BFWP using OxCal |
Impact | None as yet |
Start Year | 2017 |
Description | Scanning XRF analysis of sediment cores from Jamaica and Barbuda |
Organisation | University of Exeter |
Department | College of Life and Environmental Sciences |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Cores provided for XRF analysis |
Collaborator Contribution | XRF analysis of sediment cores |
Impact | None to date |
Start Year | 2015 |
Description | Synthesising regional climate records from the N. Neotropics |
Organisation | University of North Carolina at Chapel Hill |
Country | United States |
Sector | Academic/University |
PI Contribution | Collaborative work on synthesis of climate records. |
Collaborator Contribution | Collaborative work on synthesis of climate records. |
Impact | Presentation at forthcoming PAGES conference in Zaragoza, Spain (2017) |
Start Year | 2016 |
Description | Synthesising regional climate records from the N. Neotropics |
Organisation | University of Tennessee |
Country | United States |
Sector | Academic/University |
PI Contribution | Collaborative work on synthesis of climate records. |
Collaborator Contribution | Collaborative work on synthesis of climate records. |
Impact | Presentation at forthcoming PAGES conference in Zaragoza, Spain (2017) |
Start Year | 2016 |
Description | XRF core scanning Yaal Chac |
Organisation | Aberystwyth University |
Department | Department of Geography and Earth Sciences |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Cores provided |
Collaborator Contribution | XRF core scanning |
Impact | None to date for this project |
Start Year | 2013 |
Description | 6th Form Talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Talk to 6th form geography and politics students reported in college newsletter, which is circulated to all staff and parents of this large (almost 1800 on roll) 6th form college. |
Year(s) Of Engagement Activity | 2016 |
Description | School talk, Sutton Grammer School 'Climate change past, present and future' |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | General talk on climate change to a school Geography society (years 11 through to 13, including several teachers) - 30 attendees. The talk reached out to several students who had applied to study Geography at university. |
Year(s) Of Engagement Activity | 2019 |