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Peter Gaube

Principal Oceanographer

Email

pgaube@apl.washington.edu

Phone

206-616-0611

Education

B.A. Ecology and Evolutionary Biology, University of Arizona, 2003

M.S. Physical Oceanography, Nova Southeastern University, 2007

Ph.D. Oceanography, Oregon State University, 2012

Peter Gaube's Website

http://gaubelab.org

Publications

2000-present and while at APL-UW

Mesoscale eddies structure mesopelagic communities

Della Penna, A., and P. Gaube, "Mesoscale eddies structure mesopelagic communities," Front. Mar. Sci., 7, 454, doi:10.3389/fmars.2020.00454, 2020.

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8 Jul 2020

Mesoscale eddies play a key role in structuring open ocean ecosystems, affecting the entire trophic web from primary producers to large pelagic predators including sharks and elephant seals. Recent advances in the tracking of pelagic predators have revealed that these animals forage in the mesopelagic and the depth and duration of their foraging dives are affected by the presence of eddies. The ways in which eddies impact the distribution of mesopelagic micronekton, however, remain largely unknown. During a multi-seasonal experiment we used a shipboard scientific echosounder transmitting at 38 kHz to observe the distribution of acoustic backscattering in the energetic mesoscale eddy field of the northwestern Atlantic. Observations were collected at 24 stations with 6 located in anticyclonic and 7 in cyclonic eddies. The sampled anticyclonic eddies are characterized by intense acoustic backscattering in the mesopelagic and changes in the intensity of acoustic backscattering layers match gradients of surface properties. Furthermore, mesopelagic daytime backscattering is positively correlated with sea level anomaly. These results suggest that anticyclonic eddies in the northwestern Atlantic impact the distribution of mesopelagic micronekton and may have the potential to locally enhance or structure spatially mesopelagic communities.

Shifts in phytoplankton community structure across an anticyclonic eddy revealed from high spectral resolution lidar scattering measurements

Schulien, J.A., A. Della Penna, P. Gaube, A.P. Chase, N. Haëntjens, J.R. Graff, J.W. Hair, C.A. Hostetler, A.J. Scarino, E.S. Boss, L. Karp-Boss, and M.J. Behrenfeld, "Shifts in phytoplankton community structure across an anticyclonic eddy revealed from high spectral resolution lidar scattering measurements," Front. Mar. Sci., 7, doi:10.3389/fmars.2020.00493, 2020.

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30 Jun 2020

Changes in airborne high spectral resolution lidar (HSRL) measurements of scattering, depolarization, and attenuation coincided with a shift in phytoplankton community composition across an anticyclonic eddy in the North Atlantic. We normalized the total depolarization ratio (δ) by the particulate backscattering coefficient (bbp) to account for the covariance in δ and bbp that has been attributed to multiple scattering. A 15% increase in δ/bbp inside the eddy coincided with decreased phytoplankton biomass and a shift to smaller and more elongated phytoplankton cells. Taxonomic changes (reduced dinoflagellate relative abundance inside the eddy) were also observed. The δ signal is thus potentially most sensitive to changes in phytoplankton shape because neither the observed change in the particle size distribution (PSD) nor refractive index (assuming average refractive indices) are consistent with previous theoretical modeling results. We additionally calculated chlorophyll-a (Chl) concentrations from measurements of the diffuse light attenuation coefficient (Kd) and divided by bbp to evaluate another optical metric of phytoplankton community composition (Chl:bbp), which decreased by more than a factor of two inside the eddy. This case study demonstrates that the HSRL is able to detect changes in phytoplankton community composition. High spectral resolution lidar measurements reveal complex structures in both the vertical and horizontal distribution of phytoplankton in the mixed layer providing a valuable new tool to support other remote sensing techniques for studying mixed layer dynamics. Our results identify fronts at the periphery of mesoscale eddies as locations of abrupt changes in near-surface optical properties.

Eddy-modified iron, light, and phytoplankton cell division rates in the simulated Southern Ocean

Rohr, T., C. Harrison, M.C. Long, P. Gaube, and S.C. Doney, "Eddy-modified iron, light, and phytoplankton cell division rates in the simulated Southern Ocean," Global Biogeochem. Cycles, 34, e 2019GV006380, doi:10.1029/2019GB006380, 2020.

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1 Jun 2020

We examine the effects of Southern Ocean eddies on phytoplankton cell division rates in a global, multiyear, eddy‐resolving, 3‐D ocean simulation of the Community Earth System Model. We first identify and track eddies in the simulation and validate their distribution and demographics against observed eddy trajectory characteristics. Next, we examine how simulated cyclones and anticyclones differentially modify iron, light, and ultimately population‐specific cell division rates. We use an eddy‐centric, depth‐averaged framework to explicitly examine the dynamics of the phytoplankton population across the entire water column within an eddy. We find that population‐averaged iron availability is elevated in anticyclones throughout the year. The dominant mechanism responsible for vertically transporting iron from depth in anticyclones is eddy‐induced Ekman upwelling. During winter, in regions with deep climatological mixed layer depths, anticyclones also induce anomalously deep mixed layer depths, which further supply new iron from depth via an increased upward mixing flux. However, this additional contribution comes at the price of deteriorating light availability as biomass is distributed deeper in the water column. Therefore, even though population‐averaged specific division rates are elevated in Southern Ocean anticyclones throughout most of the year, in the winter, severe light stress can dominate relieved iron stress and lead to depressed division rates in some anticyclones, particularly in the deep mixing South Pacific Antarctic Circumpolar Current. The opposite is true in cyclones, which exhibit a consistently symmetric physical and biogeochemical response relative to anticyclones.

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In The News

Billfish expedition to the Red Sea

Sport Fishing, Martin Arostegui

This was not a vacation trip but rather a research fishing expedition with the express goal of outfitting swordfish and other large pelagic fish in the Red Sea with satellite tags to study their movement behavior.

4 Feb 2020

South Florida fishermen part of ambitious and revolutionary tagging program for swordfish

Miami Herald, Steve Waters

South Florida fishermen are helping fisheries scientists to better understand swordfish as well as uncharted ocean depths through an ambitious, revolutionary satellite tagging program. The tags will enable University of Washington scientists Peter Gaube and Camrin Braun to learn new information about swordfish, which spend most of their lives in what the researchers call the ocean twilight zone.

27 Dec 2019

Swordfish as oceanographers? Satellite tags allow research of ocean's 'twilight zone' off Florida

UW News, Hannah Hickey

Researchers from the University of Washington are using high-tech tags to record the movements of swordfish – big, deep-water, migratory, open-ocean fish that are poorly studied – and get a window into the ocean depths they inhabit.

4 Nov 2019

More News Items

Inventions

Continuous Underway Multi-sensor Profiler

Record of Invention Number: 48207

Peter Gaube, Kyla Drushka

Disclosure

15 Nov 2017

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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