Tom Marchitto

Research

Paleoceanographers deploy a multicorer aboard the R/V Knorr in the Florida Straits. This coring device is designed to capture multiple undisturbed samples of the sediment-water interface. Photo credit: Tom Marchitto.

These are some of my current research projects. I am also continually collaborating on multiple paleoceanographic studies spanning from the Pliocene to the Anthropocene.

Timing and Paleoceanographic Impacts of the Onset of Arctic-Baffin Bay Throughflow
PI: Anne Jennings; co-PIs: John Andrews, Alex Jahn, Tom Marchitto, Julio Sepulveda; Postdocs: Lineke Woelders, Hannah Zanowski
We are using numerical modeling and multi-proxy analyses of sediment cores from northern Baffin Bay to discover the timing and consequences of the Holocene (post-glacial) opening of the western gateway for Arctic freshwater to the Labrador Sea. We hypothesize that the establishment of this connection through the Canadian archipelago was important for the Atlantic meridional overturning circulation (AMOC) and the development of the North Water Polynya. Supported by NSF OPP Arctic Natural Sciences (2018-2021).

Fertilizing the North Atlantic: How Greenland's Icebergs Raft Sediments into the Ocean
PI: Irina Overeem; co-PI: Tom Marchitto; PhD student: Ethan Pierce
The rapidly changing Greenland Ice Sheet supplies about 8% of the global riverine sediment flux to the ocean. Sediments rafted by icebergs might be an even greater flux, but constraints are poor. We are using field work, laboratory analysis, and numerical modeling to improve quantitative estimates of the modern fluxes of sediments and soluble iron (an important micronutrient) from Greenland icebergs. Supported by CU Boulder Research & Innovation Seed Grant (2018-2021).

FORABOT: An Autonomous and Accessible System for Sorting Foraminifera
Collaborative PIs: Edgar Lobaton, Tom Marchitto; co-PI: Michael Daniele
We are developing an autonomous sorting system for foraminifera, which will be accessible (in terms of usability and cost) to the scientific community. The automated identification of forams to the species level is accomplished using machine learning, developed under our prior NSF grant "A Visual System for Autonomous Foraminifera Identification." The current system makes use of micromanipulation and microfluidics to facilitate the transport of forams from a hopper to their sorted receptacles. Supported by NSF OCE Ocean Technology and Interdisciplinary Coordination (2016-2018 & 2019-2021).

Development of Individual Foraminiferal Mg/Ca to Reconstruct Past ENSO Variability
PI: Tom Marchitto; PhD student: Brigitta Rongstad
Since planktic foraminifera only live for a few weeks, each shell provides a monthly-scale snapshot of upper ocean conditions. By measuring the paleotemperature proxy Mg/Ca in a population of individual shells, we can probe questions about past climate variance, such as seasonality and interannual variability. We are using tropical Pacific core tops to show that this method is valid, by constraining the impacts of partial dissolution, and by comparing fossil population statistics to upper ocean instrumental temperatures. We then apply the approach to infer ENSO variance during the Last Glacial Maximum. Supported by NSF OCE Paleo Perspectives on Climate Change (2016-2018).

Research Activities

Research Labs and Groups