About

Peter D. Ward is a professor in the Department of Biology at the University of Washington. His research focuses on evolution and systematics, paleobiology, and the history of life. Ward has contributed to understanding the latitudinal selectivity gradient at the end-Cretaceous mass extinction through his work on the bivalve network, and has studied the impacts of hypoxia and global warming on terrestrial extinctions during the Late Permian. He has been featured in media outlets such as KUOW, Salon.com, and bioGraphic for his research on nautilus, a 'living fossil,' and has received recognition including an honorary membership by The Rainier Club.

Research topics

• Biology
• Paleontology
• Geochemistry
• Ecology
• Climatology
• Zoology
• Fishery
• Geology
• Earth science
• Evolutionary biology
• Anatomy

Selected publications

• Comparative habits and habitat in extant and extinct nautiloid cephalopods from acoustic telemetry and stable oxygen isotope analyses

  Universität Zürich, ZORA · 2026-02-14

  articleOpen access1st authorCorresponding

  Information about behavior and habitat depths of Nautilus and Allonautilus species, the last remaining nautiloid cephalopod genera, is relevant both to paleobiologists trying to interpret the lives of extinct chambered cephalopods as well as to ecologists seeking to better understand the food webs of the Mesophotic Zone (200–800 m), fore-reef slope communities of the tropical Indopacific where these archaic animals live. One long-standing question is whether the extant nautiloid species live in deeper water than the many extinct species; a second is whether there are habitation depth differences of adult nautiloids compared to juveniles - either now or in the past. Using shell-mounted acoustic transmitters on seven different species in the two extant genera, and oxygen isotope shell thermometry on these same species as well as from fossils of 18 extinct fossil nautiloid species, we found regular, diurnal migration in only one species of each extant genus. Mature individuals in all tracked species of both genera were found to inhabit significantly shallower (and warmer) depths (~ 200 m) than the immature nautiluses and allonautiluses of the same populations (~ 350–400 m). Extinct nautiloid genera showed significantly warmer shell growth temperatures, with the single exception of Eocene through Miocene-aged species of the ammonoid-like genus Aturia, although diagenesis from not only ancient, but modern carbonates cannot be ruled out.

  PublisherDOI

• Late Jurassic true polar event revealed by paleomagnetic study in the North China Craton and its implication for regional tectonics and biota evolution in East Asia

  2025-03-14

  preprintOpen access

  The reorientation of Earth through rotation of its solid shell relative to its spin axis is known as True polar wander (TPW). It is well-documented at present, but the occurrence of TPW in the geologic past remains controversial. This is especially so for Late Jurassic TPW, where the veracity and dynamics of a particularly large shift remain debated. Here, we report three palaeomagnetic poles at 153, 147, and 141 million years (Myr) ago from the North China craton that document an ~12° southward shift in palaeolatitude from 155–147 Myr ago (~1.5° Myr-1), immediately followed by an ~10° northward displacement between 147–141 Myr ago (~1.6° Myr-1). Our data support a large round-trip TPW oscillation in the past 200 Myr. By comparison of Jurassic paleomagnetic poles of the NCC and SIB, we suggest that the Late Jurassic true polar wander event may have biased paleomagnetic results and thereby affected the interpretation of the final closure of the Mongol-Okhotsk Ocean. Combining paleomagnetic data with regional geological evidence, we propose that the Mongol-Okhotsk Ocean was closed in its eastern segment in the Late Jurassic, marking the formation of the central Asian continent. We suggest that the shifting back-and-forth of the continents may contribute to the biota evolution in East Asia and the global Jurassic–Cretaceous extinction and endemism. 

  PublisherDOI

• New paleotemperature and paleobiological results consistent with a far-traveled alternative for the Baja-BC hypothesis

  Geological Society of America eBooks · 2025-11-25

  book-chapterOpen access1st authorCorresponding

  ABSTRACT This study tested the Baja–British Columbia (Baja-BC) hypothesis using paleobiological and geochemical data in three separate ways. First, the pattern and values of paleotemperatures obtained from mollusks sampled from the Nanaimo Group, British Columbia (part of the Insular superterrane), were compared to those from basins in western North America (Sacramento and San Joaquin Valleys, California, and Rosario Basin, Baja California, Mexico) during the Coniacian–Maastrichtian time interval. Sequentially younger fossils in the Nanaimo Group show cooling that is consistent with a northernly moving microcontinent into higher latitudes with cooler climate and seawater temperature. The fossils in the basins in western North America do not show this pattern. Second, there is a reduction in the number of ammonite species shared by the Nanaimo Group and western North American sedimentary basins during the Santonian–Maastrichtian time interval. These data are consistent with increasing distance between the two regions over Late Cretaceous time. Third, nautiloid cephalopod assemblages from the Nanaimo Group and North America basins differ sufficiently to allow estimates of the possible deep, open-water distance between the Insular superterrane and North America during the Coniacian–Maastrichtian interval. These results are all consistent with the “far-traveled” Insular microcontinent hypothesis. However, the data also suggest that the Insular superterrane could have been farther offshore than previous models invoking the Baja–British Columbia hypothesis.

  PublisherDOI

• Evidence for multimillion-year diachroneity of the paleomagnetically defined Santonian-Campanian stage boundary between its European stratotypes and Pacific Ocean basin localities

  Geological Society of America Bulletin · 2025-11-13 · 1 citations

  article1st authorCorresponding

  Abstract The recent and revolutionary decision by the International Union of Geological Sciences to formally define the Santonian-Campanian (Cretaceous) stage boundary at the paleomagnetic polarity change between magnetochron C34n (the “Cretaceous Long Normal”) and the reversed polarity of C33r dated 83.6 Ma now allows high-resolution dating of this boundary to regions both geographically far from the European stage stratotypes, but more importantly, to regions that share few or none of the biostratigraphically important species that help define these stages in their stratotype regions. However, as demonstrated here, a significant error in the identification of the biostratigraphic zone, whose base most nearly coincides with the C34n-C33r boundary for much of the Indopacific Faunal Realm, has created a multimillion-year error in correlation to the stratotype section in Italy. Secondly, it is shown here that there appears to be a misidentification of magnetochron C33r (and thus its boundaries) in the currently accepted, Campanian stage chronostratigraphy for the Northwest Pacific region (Japan and Sakhalin) of the Indopacific Faunal Realm, which further causes diachroneity. Thirdly, here for the first time, the Santonian-Campanian boundary in Antarctica can be based on magnetostratigraphy integrated to cosmopolitan (Indopacific) ammonite and inoceramid species, taxa also found in the Northeast and Northwest Pacific region, thus allowing first-order correlation. The concluding part of this paper contains a proposal for two new auxiliary stage boundary stratotypes (one for the Northeast Pacific and another on James Ross Island, Antarctica) and a proposal for defining a three-substage Campanian based entirely on magnetostratigraphy integrated to high-resolution mollusk and microfossil biostratigraphy.

  PublisherDOI

• Cephalopod body size and macroecology through deep time

  Scientific Reports · 2025-08-21 · 3 citations

  articleOpen accessSenior author

  As actively swimming predators, cephalopods have played a key role regulating and engineering marine ecosystems for more than 500 million years and continue to do so. For the first time, we portray fluctuations of cephalopod body size including species from the Cambrian to today. For comparability, we determined the maximum body volumes of each species using various proxies, because classical measures like mantle length cannot be applied homologously to all groups. We separately examined Cephalopoda with orthoconic conchs (without ammonoids and coleoids), Nautilida, Ammonoida (without heteromorphs), and Neocoleoida (squids, octopuses and their ancestors). The long-term trajectories of these groups differ in their overall trends. Each of these groups reacted in other ways to the mass extinctions. All groups except the nautilids evolved species exceeding one meter in size, which belong to the marine megafauna. Nautilids and orthocones share a threshold volume of about 100 litres, while in ammonoids and neocoleoids, the limit lies closer to 500 litres.

  PublisherOA PDFDOI

• Longevity of a Threatened Species: Allonautilus scrobiculatus from Papua New Guinea

  Abstracts with programs - Geological Society of America · 2025-01-01

  articleSenior author
  PublisherDOI

• Quantifying Hydrogen Sulfide-Induced Plant Growth with δ34S, δ13C, and δ15N Isotopic Signatures

  2024-08-26

  preprintSenior author

  Hydrogen sulfide (H 2 S) impacts biological systems in multiple ways, including the arrest of aerobic respiration rendering it a highly toxic substance. However, H 2 S can paradoxically drive plant germination rates when administered in micromolar concentrations. We investigated changes in δ 34 S, δ 13 C, δ 15 N, and masses of sulfur, carbon, and nitrogen in Zea mays L. (corn) seedling stems grown at these low concentrations of H 2 S associated with growth. The δ 34 S and sulfur composition in seedlings increased with concentration, but only when grown in light-exposed conditions. Light-exposed seedlings also scored lower in both compared to their dark-grown counterparts. Additionally, δ 34 S signatures in seedlings with the longest stems matched values of S 0 products of the H 2 S oxidation process within anoxygenic photosynthesis in Chlorobium tepidum. It appears from these findings that 34 S fractionation patterns in H 2 S-induced plant germination is a result of the light-dependent reactions of photosynthesis. Furthermore, this δ 34 S signature could suggest the presence of anoxygenic photosynthesis via sulfur oxidation in vascular plants, challenging the current understanding of plant evolution.

  PublisherDOI

• Dissecting 20 million years of deep-water forearc sediment routing using an integrated basin-wide Bayesian chronostratigraphic framework

  Geological Society of America Bulletin · 2024-01-31 · 7 citations

  articleOpen access

  Abstract Sedimentary deposits along convergent margins contain a record of sediment transfer and coupled tectonic processes. Deciphering the evolution of ancient convergent margins, both spatially and temporally, is challenging as their stratigraphic successions are often locally deformed, which makes it difficult to correlate stratigraphic units over large distances, and they may have limited age constraints. Here, we construct a novel Bayesian chronostratigraphic framework for Late Cretaceous–Paleocene units of the Nanaimo forearc basin in western British Columbia, Canada, which reveals unparalleled detail into long-term sedimentation processes along an active deep-water margin. The Upper Nanaimo Group outcrop belt features ~2000 m of forearc basin fill that includes the deposits of multiple submarine channel systems along a 160-km-long depositional strike-oriented cross section of the ancient continental margin. The age and longevity of individual slope-channel systems was determined by constructing a Bayesian Monte Carlo numerical model in which biostratigraphic and magnetostratigraphic measurements were used to further constrain 37 detrital zircon maximum depositional ages. Important context for the refined maximum depositional ages is provided by a detailed stratigraphic dataset composed of 2199 m of measured stratigraphic section and 4207 paleoflow measurements, which demonstrate the facies, architecture, distribution, and orientation of 12 slope-channel systems. In combination, our results reconstruct the spatio-temporal evolution of coarse-grained, deep-water sediment routing along the paleo-margin and enable the timing of sedimentation to be compared with hinterland and forearc processes. Our integrative approach demonstrates that submarine channel-system deposits of the upper Nanaimo Group cluster into three long-lived fairways (8–18 m.y.), each of which has a unique depositional history. Along-strike variations in the timing of sediment routing, channel-system architecture, and channel-system orientation are interpreted to be driven by local subsidence, magmatism, and subduction-related processes. We show, for the first time, how Bayesian age models can be applied at a basin-scale to produce robust chronostratigraphic frameworks for deciphering basin evolution that provide valuable insight into long-term geodynamic processes.

  PublisherOA PDFDOI

• Completing the loop of the Late Jurassic–Early Cretaceous true polar wander event

  Nature Communications · 2024-03-12 · 12 citations

  articleOpen access

  Abstract The reorientation of Earth through rotation of its solid shell relative to its spin axis is known as True polar wander (TPW). It is well-documented at present, but the occurrence of TPW in the geologic past remains controversial. This is especially so for Late Jurassic TPW, where the veracity and dynamics of a particularly large shift remain debated. Here, we report three palaeomagnetic poles at 153, 147, and 141 million years (Myr) ago from the North China craton that document an ~ 12° southward shift in palaeolatitude from 155–147 Myr ago (~1.5° Myr −1 ), immediately followed by an ~ 10° northward displacement between 147–141 Myr ago (~1.6° Myr −1 ). Our data support a large round-trip TPW oscillation in the past 200 Myr and we suggest that the shifting back-and-forth of the continents may contribute to the biota evolution in East Asia and the global Jurassic–Cretaceous extinction and endemism.

  PublisherOA PDFDOI

• Three new species of Nautilus Linnaeus, 1758 (Mollusca, Cephalopoda) from the Coral Sea and South Pacific

  Global Biodiversity Information Facility · 2023-01-01

  datasetOpen accessSenior author

  This dataset contains the digitized treatments in Plazi based on the original journal article Barord, Gregory J., Combosch, David J., Giribet, Gonzalo, Landman, Neil, Lemer, Sarah, Veloso, Job, Ward, Peter D. (2023): Three new species of Nautilus Linnaeus, 1758 (Mollusca, Cephalopoda) from the Coral Sea and South Pacific. ZooKeys 1143: 51-69, DOI: http://dx.doi.org/10.3897/zookeys.1143.84427, URL: http://dx.doi.org/10.3897/zookeys.1143.84427

  PublisherDOI

Recent grants

• Collaborative Research: Testing Hypotheses of Global Warming during Three Major Mass Extinctions

  NSF · $87k · 2007–2010

• Collaborative Research: Upper Cretaceous-lower Paleocene Strata from the Antarctic Peninsula: Chemo-, Magneto-, and Biomarker Tests of Correlation and Extinction Hypotheses

  NSF · $419k · 2008–2011

Frequent coauthors

• Joseph L. Kirschvink

  Life Science Institute

  42 shared

• Geoffrey H. Garrison

  Earth and Space Research

  32 shared

• D. E. Brownlee

  University of Washington

  31 shared

• Roger M. H. Smith

  University of the Witwatersrand

  24 shared

• Gregory J. Barord

  24 shared

• Roger Buick

  University of Washington

  22 shared

• James W. Haggart

  21 shared

• Kenneth L. Verosub

  University of California, Davis

  18 shared

Education

• Ph.D., Geology

  University of Washington

  1982

• M.S., Geology

  University of California, Santa Barbara

  1977

• B.S., Geology

  University of California, Santa Barbara

  1975

Awards & honors

• honorary membership by The Rainier Club (October 19, 2021)