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Shumardiid trilobites had a small, unique morphology, and formed a key constituent in trilobite faunas during the Cambrian–Ordovician. Because of their unusual morphology, they have been the subject of research s, into various aspects such as their life habit, functional morphology, evolutionary origin and ontogeny. Originally, a flat, adult-like protaspid morphology was suggested for shumardiids, but subsequently a bulbous protaspid morphology interpreted to be associated with metamorphosis was also suggested for this unique trilobite group. This article documents the ontogeny of the two co-occurring shumardiid trilobites, Akoldinioidia latus Park and Kihm and Koldinioidia choii Park and Kihm, from the middle Furongian Hwajeol Formation, Taebaeksan Basin, Korea. Interestingly, protaspides of the two shumardiids have a bulbous morphology. Given the stratigraphic occurrences of the two shumardiids, it can be inferred that commutavi protaspis appeared quite early in the shumardiid evolution. The co-occurrence of the two closely related trilobites is reminiscent of sexual dimorphism, although further evidence is required to prove it. The appearance of metamorphosis-undergoing protaspides in the Furongian shumardiids may have been due to the onset of increasing ecological pressure in the early phase of the Great Ordovician Biodiversification Event. Copyright © Cambridge University Press 2017


News Article | May 15, 2017
Site: www.chromatographytechniques.com

To outer space and the deep ocean, add “beneath the ice” to the list of rarely charted frontiers of science exploration. There have been very few expeditions where robots dived beneath polar ice shelves to characterize and measure them. UC Davis engineering professor Alexander Forrest recently returned from one of them. Forrest led a six-member robotics team in Antarctica on the Western Ross Sea and Terra Nova Bay as part of an international expedition, LIONESS, led by the Korea Polar Research Institute. That stands for Land-Ice/Ocean Network Exploration with Semiautonomous Systems. The team spent nearly two months in January and February aboard the South Korean icebreaker R/V Araon. Their mission? Deploy two robots, or autonomous underwater vehicles (AUV) —  one to dive beneath the sea ice to map the bottom of the Nansen ice shelf, from which two Manhattan-sized icebergs broke last year. The other, a glider with wings named Storm Petrel, to patrol the front of the ice shelf for 10 days, looking for evidence of freshwater and capturing change over time. Why? Ultimately, to better predict how — and when — ice shelves collapse. “Ice shelves are melting,” Forrest said. “We know this. But we don’t know how fast they’re melting. To actually make on-site measurements is the next step. We’re trying to get a baseline understanding of what changes are happening in the Antarctic. As a global community, we don’t really understand what we’re losing.” From one pole to the other This July, the team will head in the opposite direction, to the Arctic’s Milne Fjord, where Forrest and colleagues plan to study the last epishelf lake in Canada. Epishelf lakes form when meltwater flowing off a glacier is trapped behind a floating ice shelf. As ice shelves in the Arctic disappear, so do the epishelf lakes dammed behind them. While Canada may soon be epishelf-free, others remain in Greenland and Antarctica. The research is intended to better explain time scales, as ice shelves are melting faster than scientists earlier predicted. “It comes down to understanding how this environment is now so we can understand how potential future climate scenarios will drive these systems in Greenland and Antarctica, as well,” Forrest said. When not swimming alongside polar ice, the Storm Petrel glider trades the ocean for freshwater. It’s currently settling in to its new home at Lake Tahoe, which stretches across the California and Nevada borders. The UC Davis Tahoe Environmental Research Center plans to deploy it in the lake early this summer. The plan is for the glider to take continuous measurements, provide real-time information to TERC’s network of instrumented buoys, chase storm events, and ultimately help round out the picture of the processes and impacts affecting Lake Tahoe. “Lakes are highly variable, both spatially and in time,” said Geoffrey Schladow, director of the UC Davis Tahoe Environmental Research Center. “Conventional measurements cannot capture this dynamism. But with a glider operating for weeks at a time, from the surface to the very bottom, we finally have the appropriate tool.” Lake Tahoe is getting “smarter” all the time with its network of nearshore sensors, NASA buoys and good old-fashioned manual sampling from TERC’s research vessel. But the glider can do something those other tools cannot: Move around the lake in bad weather and rough conditions. And, as nearly everyone who studies freshwater lakes can attest, bad weather — with its mixing, churning, swelling and upwelling — is when everything really interesting happens in a lake. Be it at the poles, or in a California lake, the data these robots collect are helping to shape the picture of how aquatic environments are changing, and what might be expected in the years to come.


News Article | May 15, 2017
Site: www.futurity.org

An iceberg off the inlet of Jang Bogo Station in Terra Nova Bay, Antarctica. (Credit: Damien Guihen/University of Tasmania) A teal ribbon of water flows on top of a glacier at Inaccessible Island, an extinct volcano and protected wildlife reserve in the South Atlantic Ocean. An uncommon sight, the researchers were unsure whether the ocean was rising over the ice, or whether freshwater was melting and flowing downward in this shot. The small black dots to the right of the teal green water are seals basking in the sun. (Credit: Damien Guihen/University of Tasmania) Adélie penguins live only in Antarctica. They are seen here with a seal in the background. Alex Forrest was amazed by Antarctica’s wildlife. He said that, unlike in the Arctic, wildlife in Antarctica have few predators, so they had little fear of humans. (Credit: Danielle Haulsee/University of Delaware) The underwater glider Storm Petrel makes its maiden voyage. After this initial round, the team processed the data and then sent it out again for its full 7-day mission. (Credit: Damien Guihen/University of Tasmania) Engineers Alex Forrest from UC Davis and Nathan Kemp (in orange) from Blue Ocean Monitoring ballast the autonomous underwater vehicle Gavia, testing its stability in calm water for later deployment in Terra Nova Bay in Antarctica. (Credit: Damien Guihen/University of Tasmania) UC Davis engineering professor Alex Forrest with the recovered underwater glider after its seven-day mission diving in Terra Nova Bay, Antarctica. (Credit: Damien Guihen/University of Tasmania) UC Davis engineering professor Alex Forrest, in orange jacket, and Nathan Kemp from Blue Ocean Monitoring out of Perth, Australia, do field repairs on the autonomous underwater vehicle (AUV) glider, Gavia. Much of their time was spent preparing and debugging the robots, which also included an AUV with wings, named “Storm Petrel.” (Credit: Damien Guihen/University of Tasmania) Fishing for a glider: Damien Guihen with the University of Tasmania and Xian Wei Wang, from New York University in Abu Dhabi, retrieve the autonomous underwater vehicle. (Credit Cassie Bongiovanni/University of New Hampshire) The R/V Araon, a South Korean icebreaker, moves through ice and ocean just offshore Jang Bogo Station in Antarctica. This shot was captured with an unmanned aerial vehicle. (Credit: Damien Guihen/University of Tasmania) A team of scientists is using robots to measure and map ice shelves in Antarctica, hoping to deepen our understanding of how the shelves collapse and change under the pressure of climate change. Alexander Forrest led a six-member robotics team in Antarctica on the Western Ross Sea and Terra Nova Bay as part of an international expedition, LIONESS, led by the Korea Polar Research Institute. That stands for Land-Ice/Ocean Network Exploration with Semiautonomous Systems. The team spent nearly two months in January and February aboard the South Korean icebreaker R/V Araon. Their mission: Deploy two robots, or autonomous underwater vehicles (AUV)—one to dive beneath the sea ice to map the bottom of the Nansen ice shelf, from which two Manhattan-sized icebergs broke last year. The other, a glider with wings named Storm Petrel, to patrol the front of the ice shelf for 10 days, looking for evidence of freshwater and capturing change over time. Why? Ultimately, to better predict how—and when—ice shelves collapse. “Ice shelves are melting,” says Forrest, an engineering professor at the University of California, Davis. “We know this. But we don’t know how fast they’re melting. To actually make on-site measurements is the next step. We’re trying to get a baseline understanding of what changes are happening in the Antarctic. “As a global community, we don’t really understand what we’re losing.” This July, the team will head in the opposite direction, to the Arctic’s Milne Fjord, where Forrest and colleagues plan to study the last epishelf lake in Canada. Epishelf lakes form when meltwater flowing off a glacier is trapped behind a floating ice shelf. As ice shelves in the Arctic disappear, so do the epishelf lakes dammed behind them. While Canada may soon be epishelf-free, others remain in Greenland and Antarctica. The research is intended to better explain time scales, as ice shelves are melting faster than scientists earlier predicted. “It comes down to understanding how this environment is now so we can understand how potential future climate scenarios will drive these systems in Greenland and Antarctica, as well,” Forrest says. When not swimming alongside polar ice, the Storm Petrel glider trades the ocean for freshwater. It’s currently settling in to its new home at Lake Tahoe, which stretches across the California and Nevada borders. The UC Davis Tahoe Environmental Research Center (TERC) plans to deploy it in the lake early this summer. The plan is for the glider to take continuous measurements, provide real-time information to TERC’s network of instrumented buoys, chase storm events, and ultimately help round out the picture of the processes and impacts affecting Lake Tahoe. “Lakes are highly variable, both spatially and in time,” says Geoffrey Schladow, director of TERC. “Conventional measurements cannot capture this dynamism. But with a glider operating for weeks at a time, from the surface to the very bottom, we finally have the appropriate tool.” Lake Tahoe is getting “smarter” all the time with its network of nearshore sensors, NASA buoys, and good old-fashioned manual sampling from TERC’s research vessel. But the glider can do something those other tools cannot: Move around the lake in bad weather and rough conditions. And, as nearly everyone who studies freshwater lakes can attest, bad weather—with its mixing, churning, swelling, and upwelling—is when everything really interesting happens in a lake. Be it at the poles, or in a California lake, the data these robots collect are helping to shape the picture of how aquatic environments are changing, and what might be expected in the years to come.


Raymond J.A.,University of Nevada, Las Vegas | Kim H.J.,Korea Polar Research Institute | Kim H.J.,Korean University of Science and Technology
PLoS ONE | Year: 2012

Diatoms and other algae not only survive, but thrive in sea ice. Among sea ice diatoms, all species examined so far produce ice-binding proteins (IBPs), whereas no such proteins are found in non-ice-associated diatoms, which strongly suggests that IBPs are essential for survival in ice. The restricted occurrence also raises the question of how the IBP genes were acquired. Proteins with similar sequences and ice-binding activities are produced by ice-associated bacteria, and so it has previously been speculated that the genes were acquired by horizontal transfer (HGT) from bacteria. Here we report several new IBP sequences from three types of ice algae, which together with previously determined sequences reveal a phylogeny that is completely incongruent with algal phylogeny, and that can be most easily explained by HGT. HGT is also supported by the finding that the closest matches to the algal IBP genes are all bacterial genes and that the algal IBP genes lack introns. We also describe a highly freeze-tolerant bacterium from the bottom layer of Antarctic sea ice that produces an IBP with 47% amino acid identity to a diatom IBP from the same layer, demonstrating at least an opportunity for gene transfer. Together, these results suggest that the success of diatoms and other algae in sea ice can be at least partly attributed to their acquisition of prokaryotic IBP genes. © 2012 Raymond, Kim.


News Article | March 26, 2016
Site: www.techtimes.com

The Antarctica seabirds, the brown skuas (Stercorarius Antarcticus) seem to have the ability to recognize humans after brief interactions, claim a group of researchers from South Korea. Birds that live among human habitation such as crows, parrots, magpies and mockingbirds have been known to display traits of recognizing humans. But in the case of skua birds, they live remotely in Antarctica with hardly any contact with humans, and hence it makes it an amazing fete. "It is amazing that brown skuas, which evolved and lived in human-free habitats, recognized individual humans just after 3 or 4 visits. It seems that they have very high levels of cognitive abilities," exclaimed Won Young Lee, one of the senior study researchers. Researchers from the Korea Polar Research Institute, South Korea, ventured into Antarctica to essentially study the breeding behavior of brown skuas. For this purpose, researchers had to physically examine the nests and eggs. In the process, they began to realize that these seabirds could actually recognize those researchers who got too close to their nests or eggs. Following which, the birds would display aggressive behavior and try to carry out focused attacks aimed at the "intruders". The researchers who did not disturb their nest were left alone. "I had to defend myself against the skuas' attack," said Yeong-Deok Han, a Ph.D. student at Inha University. "When I was with other researchers, the birds flew over me and tried to hit me. Even when I changed my field clothes, they followed me. The birds seemed to know me no matter what I wear." There are predominantly two hypotheses that have been arrived at by the researchers in their study towards determining how animals in the wild distinguish humans. One hypothesis is that they possess pre-existing intelligence that helps them distinguish and the other is that they acquire this ability through periodic exposure to humans. The interesting details of the study have been published in the journal Animal Cognition dated March 3.


News Article | March 25, 2016
Site: phys.org

Scientists in South Korea studied brown skuas living in Antarctica and reported that these birds too recognize people who had previously accessed the nests to measure their eggs and nestlings. "I had to defend myself against the skuas' attack," says Yeong-Deok Han, a PhD student at Inha University. "When I was with other researchers, the birds flew over me and tried to hit me. Even when I changed my field clothes, they followed me. The birds seemed to know me no matter what I wear." The research team performed a series of experiments. The researchers checked the nests once a week to monitor the breeding status, and the skuas attacked at closer distances with repeated visits of the researchers. To test if the birds specifically distinguish the researchers who visited the nests from those who did not, a pair of humans consisting of nest intruder (who accessed the nests) and neutral human (who never accessed the nests before) approached to the nests and walked towards the opposite directions. All seven skua pairs followed and tried to attack the nest intruder but never followed the neutral human. "It is amazing that brown skuas, which evolved and lived in human-free habitats, recognized individual humans just after 3 or 4 visits. It seems that they have very high levels of cognitive abilities." says Dr. Won Young Lee, a Senior Researcher from Korea Polar Research Institute who led the research. The cognitive abilities of Antarctic animals have not been well studied before. Brown skuas have been recorded to steal food from other birds or even steal breast milk of nursing elephant seals. According to the researchers, this opportunistic feeding habits may make them cleverer with time. Dr. Lee commented: "Since this area has been inhabited by humans only after the Antarctic research stations were installed, we think that the skuas could acquire the discriminatory abilities during a short-term period of living near humans." These findings are published in the journal Animal Cognition. Check out the video to see how the birds reacted to the nest intruder in the discriminatory experiment. Explore further: I know you, bad guy! Magpies recognize humans


News Article | August 30, 2016
Site: www.chromatographytechniques.com

Historic changes to Antarctic sea ice could be unraveled using a new technique pioneered by scientists at Plymouth University. It could also potentially be used to demonstrate past alterations to glaciers and ice shelves caused by climatic changes, a study published in Nature Communications suggests. The new method builds on an existing technique, also developed by Plymouth University over the last 10 years, which identified a means by which scientists could measure changes to sea ice in the Arctic. That has already led scientists to reveal periods when the Arctic was previously ice free during summers, and when sea ice first expanded to is modern extent. "In addition to allowing us to unlock historical changes to Antarctic sea ice, our new method also has the potential to provide further insights into other critical climatic features that may have changed in the past. Indeed, sea ice around the Antarctic coastline is strongly influenced by nearby glaciers and ice shelves, both of which contribute to increased global sea level when they melt. Therefore, our new approach may also permit a much broader spectrum of climatic changes to be unraveled in the future," said Simon Belt, professor of chemistry at Plymouth University and lead author on the study. The previous technique is based on the presence of IP25 (ice proxy with 25 carbon atoms), a lipid chemical made solely by microalgae that live in the bottom of Arctic sea ice. When the ice melts, the algae and its lipids fall into the sediments that can be recovered, dated and analyzed. IP25 does not exist in the Antarctic, but scientists from Plymouth - working with colleagues from Hanyang University, the Korea Polar Research Institute, the British Antarctic Survey and Isoprime Limited - have discovered a related chemical in the Southern Ocean. Analysis of surface sediments covering different regions of Antarctica - including the Weddell Sea, the Antarctic Peninsula, the Bellingshausen Sea and the Ross Sea - showed the presence of IPSO25 (ice proxy for the Southern Ocean with 25 carbon atoms) in nearly all cases. Its source, Berkeleya adeliensis, is a widespread and commonly occurring constituent of microalgae inhabiting Antarctic sea ice, which explains why IPSO25 is so common in the sediments. "The identification of IPSO25 in the Antarctic sea ice diatom Berkeleya adeliensis likely ensures that future interpretations of the sedimentary occurrence of this sea ice proxy can be made with greater confidence and in more detail. Thus, in addition to representing a qualitative measure of the past occurrence of Antarctic landfast ice during late spring/summer, our findings indicate that variability in sedimentary IPSO25 potentially provides further insights into changes to ice shelf and glacial melt processes in long-term records," the paper concludes.


Kim B.-M.,Korea Polar Research Institute | An S.-I.,Yonsei University
Journal of Climate | Year: 2011

The regime behavior of the low-order El Niño-Southern Oscillation (ENSO) model, according to an increase in the radiative-convective equilibrium sea surface temperature (SST; Tr), is studied to provide a possible explanation for the observed increase in ENSO irregularity characterized by decadal modulation. During recent decades, a clear increasing trend of the warm-pool SST has been observed. In this study, the increase in the warm-pool maximum SST is interpreted as an increase in Tr following previous studies. A bifurcation analysis with Tr as a control parameter is conducted to reveal that the degree of ENSO irregularity in the model is effectively controlled by the equilibrium states of the model. At a critical value of Tr, bifurcation analysis reveals that period-doubling bifurcation occurs and an amplitude-modulated ENSO emerges. At this point, a subcycle appears within the preexisting ENSO cycle, which initiates decadal modulation of ENSO. As Tr increases further, nested oscillations are successively generated, illustrating clear decadal modulation of ENSO. The qualitative regime changes revealed in this study are supported by the observation of regime shifts in the 1970s. With increasing Tr, the mean zonal SST gradient increases, and the model adjusts toward a "La Niña-like" mean state. Further constraint with shoaling of the mean thermocline depth and increasing stratification causes ENSO to exhibit stronger amplitude modulation. Furthermore, the timing of the period-doubling bifurcation advances with these two effects. © 2011 American Meteorological Society.


Kim S.-Y.,Korea Polar Research Institute | Lim D.-I.,Korea Advanced Institute of Science and Technology
Progress in Oceanography | Year: 2014

Marine microfossil assemblages in core sediments from the northern East China Sea (ECS) were investigated to understand late Holocene paleoclimatic changes in the northwestern Pacific margin. We find a pronounced alternation of ocean condition during the late Holocene characterized by an abrupt decrease in dinoflagellate cysts and Kuroshio water species of planktonic foraminifera centered at ca. 4000-2500 14C yr BP. Compilation and merger of new and previously published data show that this oceanic event corresponds with terrestrial cooling and dry episodes in the northern China. The synchronicity between marine and terrestrial records is considered to be linked to a weakened Kuroshio influence that is in coupled with intensified winter monsoon, highlighting a significance of oceanic-atmospheric dynamics in determining moisture and heat distribution over both oceanic and terrestrial domains. Superimposed on the late Holocene, the synchronicity between this particular climatic shift in the northwestern Pacific and the Neoglacial cold events in the northern high-latitude regions is tentatively indicative of a global climate signal, possibly associated with dynamics of the North Pacific gyre system and the high latitude North Atlantic thermohaline circulation, and therefore positions of the mean latitude of the Kuroshio extension. © 2014 Elsevier Ltd.


Notothenia coriiceps, a typical Antarctic notothenioid teleost, has evolved to adapt to the extreme Antarctic marine environment. We previously reported an extensive analysis of the Antarctic notothenioid transcriptome. In this study, we focused on a key component of the innate immune system, the Toll-like receptors (TLRs). We cloned the full-length sequence of 12 TLRs of N. coriiceps. The N. coriiceps transcriptome for TLR homologue (ncTLR) genes encode a typical TLR structure, with multiple extracellular leucine-rich regions and an intracellular Toll/IL-1 receptor (TIR) domain. Using phylogenetic analysis, we established that all of the cloned ncTLR genes could be classified into the same orthologous clade with other teleost TLRs. ncTLRs were widely expressed in various organs, with the highest expression levels observed in immune-related tissues, such as the skin, spleen, and kidney. A subset of the ncTLR genes was expressed at higher levels in fish exposed to pathogen-mimicking agonists, heat-killed Escherichia coli, and polyinosinic-polycytidylic acid (poly(I:C)). However, the mechanism involved in the upregulation of TLR expression following pathogen exposure in fish is currently unknown. Further research is required to elucidate these mechanisms and to thereby increase our understanding of vertebrate immune system evolution.

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