Research

Research

Using geochemical records to track humanity’s fingerprint on Tropical Eastern Pacific ecosystems through time
February 2022 - present

The field of Historical Ecology has only just started to unravel the evolution of broader “human ecosystem- environment (HEE)” relationships. A main strategy employed by historical ecologists is to establish a “pre-impact” record that captures an ecosystem’s past natural variation, which is then used to better contextualize modern structure, function, and variability. Classic methods for this type of research typically rely on available written records such as ship logs or nautical charts13, and/or the collection of recent death assemblages or fossils of opportunistically preserved taxa. Sparse research has compiled larger datasets of multiple taxa , or used proxies to understand environmental change. This lack of multi-taxa studies and the paucity of known ecological proxies in historical research inhibits our ability to contextualise past environmental change at regional scales. The reason for the paucity of such studies to date is both practical (collecting multiple different historical datasets is time-consuming and expensive), as well as methodological (there are limited methods/proxies that are appropriate indicators of environmental change on a temporal scale relevant for historical questions). To fully interpret past impacts to ecological systems, multiple different datasets, proxies, and interdisciplinary collaborations are needed in order to synthesise the HEE history. In this STRI Tupper Fellowship, I will establish novel nutrient, climate, human diet, and faunal trophic datasets for the TEP spanning the years since significant cultural occupation, using cutting-edge molecular geochemical techniques. With these data, I aim to answer the question:

"What is the interaction of human influence, our “human fingerprint”, with environmental forces, and how have they effected TEP ecosystems through time?"

This project is highly interdisciplinary, spanning the fields of ecology, palaeontology, archaeology, oceanography, and geosciences. By applying novel molecular geochemical techniques to the extensive collections and resources of STRI’s archaeological and ecological experts, this project will transform our understanding of human impacts on the TEP from early occupation to modern day.

Historical ecology and taphonomy of Pacific reefs
Smithsonian Tropical Research Institute, Panama
January 2019 - present

Rapid sea level rise is one of the many factors impacting coral reefs around the world. Coupled with local and global anthropogenic stressors, which lower coral productivity, it is not known whether corals will survive future climate projections. However, in order to predict what will happen to corals in the future, past environmental variability’s and their effects on the ecosystem must be better understood. One opportunity for research is a recent phenomenon that occurred after the last glacial maximum known as the mid Holocene sea level highstand. This highstand was a result of variable glacial ice melts, and caused sea levels in certain areas to rise several meters higher then mean sea level today. Future ice melt is projected to cause sea level dynamics similar to those that occurred during this highstand, resulting in significant sea level increases for tropical waters that presently harbor coral reefs. However, without identifying certainly if a highstand occurred in the past, it is unlikely that we can accurately predict sea levels in the future. Therefore, this short-term fellowship aims to answer this question for Panama, a presently rich coral habitat with debated past sea level dynamics. Using sediment push-cores and coral sub-fossil data, results from this project should definitively show whether or not a highstand occurred, and what affect it had on past coral assemblages. In this way, Panama will be able to better identify high-risk reef habitats under future IPCC climate projections, and plan local conservation accordingly.

Pictures: Jorge Alemon, Aaron O'Dea, STRI. Jihane Benbahtane

Lime-kilns and their impacts to local coral reefs
National Geographic Explorer Research, Sri Lanka/Hong Kong
March 2018 - 2021

Ancient lime production in Hong Kong harvested live coral from the surrounding environment as their source material to produce slaked lime. This in turn had a direct impact on the coral ecosystem, which could have been part of what has led to its presently degraded state. Though this practice stopped in Hong Kong during the early 1900’s, a similar industry persisted in Sri Lanka until the early 2000’s, and may still continue today. This research is a hybrid of ecology and ethnoarchaeology, inferring information from Sri Lankas’ industry to help piece together Hong Kong’s past coral biodiversity. Furthermore, this project looks to investigate the present impacts of Sri Lankan coral harvesting.

Nitrogen incorporation and use as a historic proxy
The University of Hong Kong, Hong Kong
January 2017 - present

This work focuses on understanding the coral calcification process, and the nutrients the animal uses during the creation of its organic matrix. Using labeled organic and inorganic nutrients, various feeding experiments have been conducted in order to track the nutrient uptake and utilization during calcification, with a focus on nitrogen. Nitrogen is important during this process, since the organic matrix has amino acids and proteins, but to date there is limited knowledge about where and how this nitrogen is utilized by the coral. If successful, these experiments could highlight the corals nitrogen preferences, which could help to determine what changes in the species biology may occur with the constant fluxes to the nitrogen cycle. This will then help us to infer historical nitrogen signals that are obtained from fossil corals. Various techniques are being tested in this project, including isotope ecology, compound specific isotope analysis, and nanoSIMS.

The historical ecology of Hong Kong coral
The University of Hong Kong, Hong Kong
September 2016 - 2022

In this project,  historic data (coral fossils and subfossils, historic water quality and environmental data) has been collected and analyzed in order to create a historic baseline of Hong Kong's marine environment. We used our data to determine both the anthropogenic and natural stressors upon past and present coral communities. In this way, we hope to get a picture of what the ecosystem was like in the past, how and why it may have changed in the present, and look to the best steps forward for its conservation and restoration. 

Media Credit

Header photograph: Steven Hightower, @life_of_hi
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