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Research overview:
Research overview:
Climate science relies upon an expanding toolkit of geochemical techniques for quantifying climate variations over earth history prior to our observational records. But ecology is still incipient in the development of proxies for quantifying past changes. This is the gap I aim to fill through my research.
Climate science relies upon an expanding toolkit of geochemical techniques for quantifying climate variations over earth history prior to our observational records. But ecology is still incipient in the development of proxies for quantifying past changes. This is the gap I aim to fill through my research.
Using a geochemical technique -- the nitrogen isotopic composition (δ15N) of organics in fish otoliths (ear stones) -- that I developed with doctoral advisors Bess Ward and Danny Sigman at Princeton U, trophic level studies of fossil fishes are possible. I am applying this method to studies of historical (e.g., heavily fished Atlantic cod populations) and ancient (e.g., fossil otoliths from Miocene sediments) fish populations. The ultimate aim of my research is to gain a better understanding of the controls, feedbacks, and 'natural' variations in aquatic food webs. Through postdoctoral training at the Smithsonian Institution with Aaron O'Dea and UC Berkeley's Integrative Biology Department with Seth Finnegan, I am integrating paleontological methods and a deep time perspective into my research agenda.
Using a geochemical technique -- the nitrogen isotopic composition (δ15N) of organics in fish otoliths (ear stones) -- that I developed with doctoral advisors Bess Ward and Danny Sigman at Princeton U, trophic level studies of fossil fishes are possible. I am applying this method to studies of historical (e.g., heavily fished Atlantic cod populations) and ancient (e.g., fossil otoliths from Miocene sediments) fish populations. The ultimate aim of my research is to gain a better understanding of the controls, feedbacks, and 'natural' variations in aquatic food webs. Through postdoctoral training at the Smithsonian Institution with Aaron O'Dea and UC Berkeley's Integrative Biology Department with Seth Finnegan, I am integrating paleontological methods and a deep time perspective into my research agenda.
I am particularly interested in patterns relating to high trophic level fishes in marine ecosystems, as fisheries resources form the economic, cultural, and nutritional foundation of coastal communities around the world. Quantitative records of ecological variations in the past will be critical to improve predictions about the future of marine ecosystems. Due to the lack of tools available for quantifying trophic level in animals, there are still major gaps in our understanding of the importance of trophic level across extinction events, for rates of speciation within and among clades, and for long term macroevolutionary patterns broadly.
I am particularly interested in patterns relating to high trophic level fishes in marine ecosystems, as fisheries resources form the economic, cultural, and nutritional foundation of coastal communities around the world. Quantitative records of ecological variations in the past will be critical to improve predictions about the future of marine ecosystems. Due to the lack of tools available for quantifying trophic level in animals, there are still major gaps in our understanding of the importance of trophic level across extinction events, for rates of speciation within and among clades, and for long term macroevolutionary patterns broadly.
RESEARCH THEMES
RESEARCH THEMES
methods
methods
Can natural abundance stable isotopes of otolith organics be used as a tracer of fish dietary changes? Calibration, methods development, reproducibility
Proxy development of otolith-bound N isotope methods in modern and fossil otoliths
Cross-species calibration of conventional muscle tissue and new otolith N isotopic methods
N isotopic evidence for multiple otolith biomineralization pathways
Controlled laboratory diet switch quantifying the response time of otolith N to dietary changes
historical ecology
historical ecology
What was 'natural' in the past? Otolith-derived trophic level information is required because animal tissues degrade quickly (and are therefore inaccessible for isotope analyses of ancient fishes)
Paleo-oceanographic and ecological reconstruction of 7,000 year old Caribbean coral reef food webs in Panama and Dominican Republic
Relative impacts of fishing and climate on Georges Bank and Gulf of Maine Atlantic cod, 1620-2020
Oceanographic regime shifts and bottom-up effects on Icelandic food webs, 1930-2020
paleontology
paleontology
Does trophic level 'matter' for evolutionary outcomes? Detecting the drivers and consequences of fish trophic level on million-year timescales
Case studies using the Panama Isthmus as a natural experiment over the last 12 million years:
Did trophic mode affect extinction vulnerability during productivity collapse in the Neogene?
Do nutrient supply, nutrient utilization, and food web structure co-vary on long time scales?
isotopic groundtruthing
isotopic groundtruthing
Using fossil-bound N isotopes for trophic reconstruction requires consideration of temporal and spatial averaging of 'isotopic baseline'
Case study on the Northeast U.S. shelf: Multi-species, multi-trophic study: seawater nitrate isotopes, particulate nitrogen, zooplankton, and zooplanktivorous fish
Metazoan Stable Isotope Database In the Global Ocean (MSIDGO), a database of metazoan and autotrophic stable isotope data compiled from published literature
Do mesopelagic or pelagic fishes have 'better' isotopic fidelity to spatial variations in isotopic baseline?
environmental stressors
environmental stressors
Has deoxygenation of the Baltic Sea affected cod trophic dynamics over their life history?
Collaborator on Project Breathless, an NSF-funded interdisciplinary project led by Karin Limburg (SUNY-ESF)
Comparison of modern and Neolithic cod otolith chemical composition and trace elemental profiles
Micromilling methods development for nitrogen isotope composition in otoliths
biomineralization
biomineralization
What biomineralizatiion pathways are used by fishes to make their otoliths?
Comparison of otolith biomineralization pathways across different fish clades with hypothesized biomineralization differences
Polymorph selection and implications for trace elemental composition of otoliths
Carbonate precipitation rate and organic precipitation rate differences across species
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