Jacob Jaskiel, a PhD student in the Rotjan Lab, Peter Schroedl, a PhD candidate in the Marlow Lab, and Lili Vizer, a PhD student in the Buston Lab, received the Warren McLeod Summer Award.
Jacob studies tropical Pacific tunas including skipjack, yellowfin, and bigeye, which constitute some of the world’s largest wild capture fisheries. His research focuses on questions relating to large-scale basin-wide population dynamics, as well as larval dynamics potentially affecting recruitment (e.g. predator-prey interactions). Jacob’s fisheries-independent research relies largely on high-resolution zooplankton sampling inside the Phoenix Islands Protected Area (PIPA), and employs next-generation sequencing, metabarcoding, and community assemblage analyses to: 1) understand which tuna species utilized PIPA as a spawning ground during its fully no-take status, how their populations are structured, and what their recent demographic histories were; 2) Identify important trophic linkages involving tuna larvae through 18s rRNA sequencing of larval gut contents; and 3) Leverage a dataset of over 20,000 larval fish (N=1,141 tuna) and 80,000 individually identified zooplankton to characterize persistent assemblages containing tuna larvae, additionally combining information on larval diets from Chapter 2 to make inferences about larval ecology and planktonic interactions possibly influencing recruitment.
During Jacob’s Warren-McLeod Fellowship, he will process and analyze 18s v9 rRNA sequencing data of gut contents, resulting in the first characterization of larval tuna diets in the central Pacific Ocean. Larval tuna feeding preferences have been studied in other regions, yielding fascinating insights into trophic niche partitioning and other ecological dynamics, but no such studies have been conducted within the Western and Central Pacific, a region that supplies over half of the world’s tuna. Investigating tuna feeding ecology during their most critically important life history stage is a necessary step in gaining a holistic, ecosystem-informed perspective on the factors governing the successful recruitment of larvae and juveniles to the fisheries on which millions of people depend.
Peter is a 5th year phd candidate in the Marlow Geomicrobiology Lab. His phd focuses on microbe-mineral interactions in extreme environments. At the ~4,000m deep Clarion-Clipperton Zone in the heart of the Pacific Ocean, polymetallic nodules rich in iron, manganese, copper, cobalt, and other valuable metals carpet the seafloor. They are found in discrete regions within every ocean basin and many freshwater lakes on Earth. On a UN mandated environmental impact assessment, our collaborator Dr. Andrew Sweetman studied seafloor ecology with deep-sea landers. He measured unexpected seafloor increases in oxygen on this and other cruises. Shipboard, we also preserved samples for future analyses and detected populations of microbes capable of dark oxygen production and biomineralization. This fellowship will aid in our understanding of the geomicrobial mechanisms impacting polymetallic nodule formation and dark oxygen production in the deep-sea and perhaps other valuable ecosystems (e.g. subsurface aquifers) which have also been found to generate oxygen without photosynthesis.