UBC researchers believe a group of killer whales observed hunting marine mammals including sperm whales, as well as a sea turtle, in the open ocean off California and Oregon could be a new population.

Based on available evidence, the researchers posit in a new study published in Aquatic Mammals that the 49 orcas could belong to a subpopulation of transient killer whales or a unique oceanic population found in waters off the coast of California and Oregon.

“The open ocean is the largest habitat on our planet, and observations of killer whales in the high seas are rare,” said first author Josh McInnes, a master’s student at the UBC Institute for the Oceans and Fisheries (IOF). “In this case, we’re beginning to get a sense of killer whale movements in the open ocean and how their ecology and behavior differs from populations inhabiting coastal areas.”

Three ecotypes of killer whales live along the coasts of California and Oregon: ‘residents,’ ‘transients,’ and ‘offshores’.

The unknown orcas have been spotted before, but the new paper contains a weight of evidence gathered from nine encounters with 49 animals from 1997 to 2021, enough to form a solid hypothesis, the researchers said.

“It’s pretty unique to find a new population. It takes a long time to gather photos and observations to recognize that there’s something different about these killer whales,” said co-author Dr. Andrew Trites, IOF professor.

The 49 killer whales could not be matched with any known animals through photos or descriptions. “In one of the first encounters researchers had with a pod of these oceanic killer whales, they were observed taking on a herd of nine adult female sperm whales, eventually making off with one. It is the first time killer whales have been reported to attack sperm whales on the West Coast,” said McInnes.

“Other encounters include an attack on a pygmy sperm whale, predation on a northern elephant seal and Risso’s dolphin, and what appeared to be a post-meal lull after scavenging a leatherback turtle.”

Shark scars provide vital clues

A key clue to the new population’s presumed habitat range lies in cookie-cutter shark bite scars observed on almost all of the orcas. This parasitic shark lives in the open ocean, meaning the new population primarily inhabits deep waters far from land.

The orcas also feature physical differences from the three main ecotypes, including in their dorsal fins and saddle patches—the gray or white patches by the fin.

“While the sizes and shapes of the dorsal fins and saddle patches are similar to transient and offshore ecotypes, the shape of their fins varied, from pointed-like transients to rounded-like offshore killer whales,” said McInnes. “Their saddle patch patterns also differed, with some having large uniformly gray saddle patches and others having smooth narrow saddle patches similar to those seen in killer whales in tropical regions.”

Along with marine mammal stock assessment surveys, fishermen and passengers on an open-ocean birding expedition and whale-watching tour also provided observations of the unidentified killer whales, said Dr. Trites. Spotting the new population has become something of a hobby among fishermen, some of whom have bought cameras for their trips specifically to snap an encounter, the researchers said.

The researchers hope to document more sightings and gather more information, including acoustic data about the orcas’ calls and genetic information from DNA samples to investigate further how these killer whales may differ, or not, from already documented populations.

Researchers from China and Japan have discovered distinct characteristics of Earth’s lower mantle flow field. They investigated seismic anisotropy in the upper part of the lower mantle beneath the Philippine Sea Plate (PSP) and found that the ancient lower mantle flow field is still preserved there.

The lower mantle is an important layer of the Earth and may play an important role in the evolution and material cycling of Earth’s interior. It is generally believed to be not only the final destination of subducted slabs, but also the birthplace of mantle plumes, which are two major styles in the evolution and material cycling of the Earth’s surface and interior. However, our knowledge of the characteristics of the flow field and geodynamics of the lower mantle is still deficient.

In this study, the researchers performed P-wave azimuthal anisotropy tomography to image the 3D anisotropic structure of the crust and mantle down to a depth of 1,600 km beneath the PSP. The tomographic results show that N-S fast velocity directions (FVDs) exist at depths of 700–900 km below the mid-PSP. They also observed two isolated fast velocity anomalies with NW-SE FVDs at depths of 700–1,600 km beneath the PSP.

They found that the N-S FVDs at depths of 700–900 km are not related to the slab subduction, because they occur away from the present subduction zones. They are also independent of a mantle plume, as there has been no active mantle plume beneath the PSP since the early Cenozoic.

Based on previous geodynamic simulations and seismological results, the researchers inferred that the N-S FVDs at depths of 700–900 km reflect the remnant Pacific lower mantle flow field at about 50 Ma.

In addition, the two isolated fast velocity anomalies are consistent with seismic scatterers at depths of 1,000–1,800 km detected by previous seismological studies, and their locations are generally consistent with that of the spreading center between the Izanagi and Pacific plates when this spreading center was about to subduct beneath the Eurasian Plate. Thus, the isolated fast velocity anomalies are inferred to be remnants of the subducted Izanagi slab.

“The NW-SE FVDs in the two isolated fast anomalies are further inferred to reflect the Pacific lower mantle flow field at about 40 Ma, because the two isolated fast velocity anomalies are surrounded by amorphous mantle flow field and are not affected by the present lower mantle flow,” said Prof. Fan Jianke from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS), first and corresponding author of the study.

“Our study shows that seismic anisotropy is more widespread in the lower mantle than previously thought,” said Prof. Fan. “These observations also provide important and independent seismic evidence for the existence of past deformation in the lower mantle, which can help us better understand the geodynamic properties of the lower mantle.”

April 17, 2021, was a day like any other day on the sun, until a brilliant flash erupted and an enormous cloud of solar material billowed away from our star. Such outbursts from the sun are not unusual, but this one was unusually widespread, hurling high-speed protons and electrons at velocities nearing the speed of light and striking several spacecraft across the inner solar system.

In fact, it was the first time such high-speed protons and electrons—called solar energetic particles (SEPs)—were observed by spacecraft at five different, well-separated locations between the sun and Earth as well as by spacecraft orbiting Mars. And now these diverse perspectives on the solar storm are revealing that different types of potentially dangerous SEPs can be blasted into space by different solar phenomena and in different directions, causing them to become widespread.

“SEPs can harm our technology, such as satellites, and disrupt GPS,” said Nina Dresing of the Department of Physics and Astronomy, University of Turku in Finland. “Also, humans in space or even on airplanes on polar routes can suffer harmful radiation during strong SEP events.”

Scientists like Dresing are eager to find out where these particles come from exactly—and what propels them to such high speeds—to better learn how to protect people and technology in harm’s way. Dresing led a team of scientists that analyzed what kinds of particles struck each spacecraft and when. The team published its results in the journal Astronomy & Astrophysics.

Currently on its way to Mercury, the BepiColombo spacecraft, a joint mission of ESA (the European Space Agency) and JAXA (Japan Aerospace Exploration Agency), was closest to the blast’s direct firing line and was pounded with the most intense particles. At the same time, NASA’s Parker Solar Probe and ESA’s Solar Orbiter were on opposite sides of the flare, but Parker Solar Probe was closer to the sun, so it took a harder hit than Solar Orbiter did.

Next in line was one of NASA’s two Solar Terrestrial Relations Observatory (STEREO) spacecraft, STEREO-A, followed by the NASA/ESA Solar and Heliospheric Observatory (SOHO) and NASA’s Wind spacecraft, which were closer to Earth and well away from the blast. Orbiting Mars, NASA’s MAVEN and ESA’s Mars Express spacecraft were the last to sense particles from the event.

Altogether, the particles were detected over 210 longitudinal degrees of space (almost two-thirds of the way around the sun)—which is a much wider angle than typically covered by solar outbursts. Plus, each spacecraft recorded a different flood of electrons and protons at its location. The differences in the arrival and characteristics of the particles recorded by the various spacecraft helped the scientists piece together when and under what conditions the SEPs were ejected into space.

These clues suggested to Dresing’s team that the SEPs were not blasted out by a single source all at once but propelled in different directions and at different times potentially by different types of solar eruptions.

“Multiple sources are likely contributing to this event, explaining its wide distribution,” said team member Georgia de Nolfo, a heliophysics research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Also, it appears that, for this event, protons and electrons may come from different sources.”

The team concluded that the electrons were likely driven into space quickly by the initial flash of light—a solar flare—while the protons were pushed along more slowly, likely by a shock wave from the cloud of solar material, or coronal mass ejection.

“This is not the first time that people have conjectured that electrons and protons have had different sources for their acceleration,” de Nolfo said. “This measurement was unique in that the multiple perspectives enabled scientists to separate the different processes better, to confirm that electrons and protons may originate from different processes.”

In addition to the flare and coronal mass ejection, spacecraft recorded four groups of radio bursts from the sun during the event, which could have been accompanied by four different particle blasts in different directions. This observation could help explain how the particles became so widespread.

“We had different distinct particle injection episodes—which went into significantly different directions—all contributing together to the widespread nature of the event,” Dressing said.

“This event was able to show how important multiple perspectives are in untangling the complexity of the event,” de Nolfo said.

These results show the promise of future NASA heliophysics missions that will use multiple spacecraft to study widespread phenomena, such as the Geospace Dynamics Constellation (GDC), SunRISE, PUNCH, and HelioSwarm. While single spacecraft can reveal conditions locally, multiple spacecraft orbiting in different locations provide deeper scientific insight and offer a more complete picture of what’s happening in space and around our home planet.

It also previews the work that will be done by future missions such as MUSE, IMAP, and ESCAPADE, which will study explosive solar events and the acceleration of particles into the solar system.

Hammerhead sequences copied by the lower-fidelity polymerase drift away from their original RNA sequence (top) and lose their function over time. Hammerheads catalyzed by the higher-fidelity polymerase retain function and evolve fitter sequences (bottom).

Charles Darwin described evolution as “descent with modification.” Genetic information in the form of DNA sequences is copied and passed down from one generation to the next. But this process must also be somewhat flexible, allowing slight variations of genes to arise over time and introduce new traits into the population.

But how did all of this begin? In the origins of life, long before cells and proteins and DNA, could a similar sort of evolution have taken place on a simpler scale? Scientists in the 1960s, including Salk Fellow Leslie Orgel, proposed that life began with the “RNA World,” a hypothetical era in which small, stringy RNA molecules ruled the early Earth and established the dynamics of Darwinian evolution.

New research at the Salk Institute now provides fresh insights on the origins of life, presenting compelling evidence supporting the RNA World hypothesis. The study, published in Proceedings of the National Academy of Sciences (PNAS), unveils an RNA enzyme that can make accurate copies of other functional RNA strands, while also allowing new variants of the molecule to emerge over time. These remarkable capabilities suggest the earliest forms of evolution may have occurred on a molecular scale in RNA.

The findings also bring scientists one step closer to re-creating RNA-based life in the laboratory. By modeling these primitive environments in the lab, scientists can directly test hypotheses about how life may have started on Earth, or even other planets.

“We’re chasing the dawn of evolution,” says senior author and Salk President Gerald Joyce. “By revealing these novel capabilities of RNA, we’re uncovering the potential origins of life itself, and how simple molecules could have paved the way for the complexity and diversity of life we see today.”

Scientists can use DNA to trace the history of evolution from modern plants and animals all the way back to the earliest single-celled organisms. But what came before that remains unclear. Double-stranded DNA helices are great for storing genetic information. Many of those genes ultimately code for proteins—complex molecular machines that carry out all sorts of functions to keep cells alive.

What makes RNA unique is that these molecules can do a bit of both. They’re made of extended nucleotide sequences, similar to DNA, but they can also act as enzymes to facilitate reactions, much like proteins. So, is it possible that RNA served as the precursor to life as we know it?

Scientists like Joyce have been exploring this idea for years, with a particular focus on RNA polymerase ribozymes—RNA molecules that can make copies of other RNA strands.

Over the last decade, Joyce and his team have been developing RNA polymerase ribozymes in the lab, using a form of directed evolution to produce new versions capable of replicating larger molecules. But most have come with a fatal flaw: they aren’t able to copy the sequences with a high enough accuracy. Over many generations, so many errors are introduced into the sequence that the resulting RNA strands no longer resemble the original sequence and have lost their function entirely.

Until now. The latest RNA polymerase ribozyme developed in the lab includes a number of crucial mutations that allow it to copy a strand of RNA with much higher accuracy.

In these experiments, the RNA strand being copied is a “hammerhead,” a small molecule that cleaves other RNA molecules into pieces. The researchers were surprised to find that not only did the RNA polymerase ribozyme accurately replicate functional hammerheads, but over time, new variations of the hammerheads began to emerge.

These new variants performed similarly, but their mutations made them easier to replicate, which increased their evolutionary fitness and led them to eventually dominate the lab’s hammerhead population.

“We’ve long wondered how simple life was at its beginning and when it gained the ability to start improving itself,” says first author Nikolaos Papastavrou, a research associate in Joyce’s lab.

“This study suggests the dawn of evolution could have been very early and very simple. Something at the level of individual molecules could sustain Darwinian evolution, and that might have been the spark that allowed life to become more complex, going from molecules to cells to multicellular organisms.”

The findings highlight the critical importance of replication fidelity in making evolution possible. The RNA polymerase’s copying accuracy must exceed a critical threshold to maintain heritable information over multiple generations, and this threshold would have risen as the evolving RNAs increased in size and complexity.

Joyce’s team is re-creating this process in laboratory test tubes, applying increasing selective pressure on the system to produce better-performing polymerases, with the goal of one day producing an RNA polymerase that can replicate itself. This would mark the beginnings of autonomous RNA life in the laboratory, which the researchers say could be accomplished within the next decade.

The scientists are also interested in what else might occur once this mini “RNA World” has gained more autonomy.

“We’ve seen that selection pressure can improve RNAs with an existing function, but if we let the system evolve for longer with larger populations of RNA molecules, can new functions be invented?” says co-author David Horning, a staff scientist in Joyce’s lab. “We’re excited to answer how early life could ratchet up its own complexity, using the tools developed here at Salk.”

The methods used in the Joyce lab also pave the way for future experiments testing other ideas about the origins of life, including what environmental conditions could have best supported RNA evolution, both on Earth and on other planets.

Sea-floor samples for the study were taken with this deep-sea submersible vehicle (Alvin) from inactive as well as active hydrothermal systems in several thousands of meters of water. Credit: Woods Hole Oceanographic Institution, National Deep Submergence Facility, National Science Foundation.

Under certain conditions microbial communities can grow and thrive, even in places that are seemingly uninhabitable. This is the case at inactive hydrothermal vents on the sea floor. An international team that includes researchers from MARUM—Center for Marine Environmental Sciences at the University of Bremen, is presently working to accurately quantify how much inorganic carbon can be bound in these environments.

With its high pressure, darkness, and nutrient deficiency, the deep sea is generally not a hospitable place. But in the presence of heat and a rich influx of energy-rich fluids, as is the case at active hydrothermal vents, numerous fish, shellfish, and microorganisms are able to settle there. But what happens to these biotic communities when the source of hot fluids is exhausted?

The chimneys form over long time periods when seawater seeps through cracks into the Earth’s crust, is warmed there, then dissolves and takes up minerals on its way back up to the ocean floor. This hot, mineral-rich, and often smokey water seeks the most pervious path through the Earth’s crust and encounters cold, oxygen-rich water at the sea floor.

This results in the precipitation of minerals, which are deposited as chimneys. These hydrothermal vents are energy-rich habitats based on chemosynthesis where microorganisms from the base of the food webs. Depending on the region, chimneys at hydrothermal seeps contain minerals like copper, zinc, gold, or silver. As a result, there is a growing interest in exploiting inactive smokers in deep-sea mining activities.

When the flow of mineral-rich fluids dries up, the black smokers become inactive. Larger organisms migrate away to the next vent, but the microbial communities have ways to adapt to the new conditions.

“Even forty years after the discovery of the first hydrothermal fields, we constantly learn new things about how these ecosystems work,” says Dr. Florence Schubotz of MARUM, “particularly relating to the amount of CO₂ bound up in inactive smokers, but also with regard to the volume of microbial life, its activity, and rates of production.”

Determining how densely inactive smokers are colonized is the central focus of a research project in which Schubotz is working. The work involves sampling at the exact area where the first hydrothermal vents were discovered in the eastern Pacific around four decades ago.

“The initial results indicate that even inactive smokers are important locations for microbial activity and the production of organic carbon on the sea floor. We are just beginning to understand how the carbon cycle functions in the deep sea. It is certain that carbon is fixed at such hotspots.

“But,” according to Schubotz, “we do not yet understand these ecosystems well enough to estimate the magnitudes involved.” Broad areas of the ocean floor have not yet been investigated and still unknown hydrothermal systems await discovery.

Every plate-boundary spreading center is a potential colonization area. The samples from the eastern Pacific will provide a good starting point because there is already a good understanding of the extent of microbial communities at this location. The international team has therefore investigated samples from active and inactive smokers and compared them with each other.

The team obtained the samples during three expeditions in 2019 and 2021, in part with the help of the manned submersible research vehicle Alvin, from the East Pacific Rise (9 degrees north), an oceanic ridge at a Pacific plate boundary. Their objective is to understand better the deep-sea ecosystem and the interactions between various organisms and to calculate how metabolic rates change from active to inactive systems for the first time.

“Without this kind of data,” according to the publication, “our understanding of the element cycles in the inactive-chimney ecosystem and their possible influence on the biochemistry of the deep sea remains incomplete.” The team emphasizes that such investigations are essential before any decisions can be made about deep-sea mining.

The biogeochemistry at the sea floor and the interactions of marine ecosystems with the environment are also some of the core research themes within the Cluster of Excellence, “The Ocean Floor—Earth’s Uncharted Interface.”

The findings are published in the journal Nature Microbiology.