Danny Torres ’27, Neuroscience

Danny Torres ’27

Major

Neuroscience

Project Title

Foraminifera-bound Nitrogen Isotope Measurements From the Arabian Sea Oxygen-deficient Zone Over the Last Glacial-interglacial Cycle

Presentation Link

View Danny's Presentation

Minor(s): Climate Science, Cognitive Science

I prepared samples for the analysis of nitrogen isotopic composition of organic matter trapped within planktonic (surface-dwelling) foraminifera calcite shells. This project was focused on the Arabian Sea oxygen-deficient zone (ODZ), where one-third of global marine denitrification occurs. Water column denitrification in such oxygen-starved environments is driven by bacterial respiration of nitrate, a process resulting in a preferential loss of the lighter nitrogen-14 isotope (14N), which results in higher levels of the heavier nitrogen-15 isotope (15N) in subsurface sea water. This fluctuating isotopic signature is imprinted in newly formed organic matter and is trapped within the foraminifera shells during their formation. When they die, these foraminifera shells sink to the deep ocean, where their isotopic signatures are preserved in seafloor sediments. We meticulously sorted and cleaned two species of foraminifera, some dating back 30,000 years, to prepare these ancient samples for chemical analysis and mass spectrometry, which will shed light on subtle isotopic variations tied to past ocean conditions across glacial-interglacial cycles. This experience enhanced my microscopy and laboratory techniques and deepened my appreciation for paleoceanographic research and the complex processes that govern Earth’s climate history.