The Southern Ocean is key to understanding how the Earth’s climate system regulates atmospheric CO2, and much of its history is recorded in the sediments filled with fossilized diatoms (a type of plankton). An upcoming NSF-funded, GSO-led expedition will investigate how diatoms in the Southern Ocean can help us decode these chemical signals, providing insight into nutrient cycling and climate interactions from past glacial periods to today.
From October 23 to December 6, the science team will board the RVIB Nathaniel B. Palmer for a research cruise focused on collecting water and particle samples along a transect from 67°S to 54°S. The goal is to study how diatoms build their nitrogen and silicon-rich shells and to better understand how these isotopic signals are produced and preserved in fossils. This work builds on a previous expedition in 2017, where unexpected chemical results raised questions about how recycled materials might affect the fossil record.
The team will collect many liters of water using a Niskin sampler, filter hundreds of liters of water using large pumps lowered to specific depths and conduct surface ocean net tows to capture diatoms. In shipboard culture experiments, they’ll grow live diatoms, enriching them with nutrients and using a fluorescent dye to trace how fast they produce their silica shells. This data will help scientists build models linking nitrogen and silicon isotope compositions to biological processes and ocean circulation.
The cruise welcomes NSF Polar STEAM fellows, two middle school science teachers from Oregon and Kansas, who will develop educational resources to bring polar science back into their classrooms. Additionally, Georgia Rhodes of RISD’s Nature Lab will work with the scientists on art-based approaches to visualization and creative collaboration.
Follow along with #NBP2410 and stay tuned for updates and insights from the RVIB Nathaniel B. Palmer.