Northern Hemisphere forcing of climatic cycles in Antarctica over the past 360,000 years

first_imgThe Milankovitch theory of climate change proposes that glacial–interglacial cycles are driven by changes in summer insolation at high northern latitudes. The timing of climate change in the Southern Hemisphere at glacial–interglacial transitions (which are known as terminations) relative to variations in summer insolation in the Northern Hemisphere is an important test of this hypothesis. So far, it has only been possible to apply this test to the most recent termination because the dating uncertainty associated with older terminations is too large to allow phase relationships to be determined. Here we present a new chronology of Antarctic climate change over the past 360,000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the Dome Fuji and Vostok ice cores. This ratio is a proxy for local summer insolation, and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter. The accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation. Our results indicate that orbital-scale Antarctic climate change lags Northern Hemisphere insolation by a few millennia, and that the increases in Antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of Northern Hemisphere summer insolation. These results support the Milankovitch theory that Northern Hemisphere summer insolation triggered the last four deglaciations.last_img read more

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Depth gradients in shell morphology correlate with thermal limits for activity and ice disturbance in Antarctic limpets

first_imgTo fully understand how species distributions will respond to changing environments it is essential to understand the mechanisms underlying variation in animal performance and the relative importance of different ecological and environmental factors. A performance measure that has previously been used as an indicator of thermal capacity of the Antarctic limpet (Nacella concinna) to cope with regional warming is the ability to right if removed from the substratum and turned upside down. As part of an on-going study into limpet genetics and phenotypic plasticity, we tested the temperature limits for 50% righting of limpets from 6 and 30 m depth. The 50% threshold for limpets collected from 6 m (4.7 degrees C) was higher than for those collected from 30 m (0.7 degrees C). This compares with a previously published limit of 2.2 degrees C for limpets collected from 12-15 m at the same location. These thermal limits positively correlated with a depth gradient in shell height to length ratio; thickness and strength. Flatter limpets, had a reduced thermal limit for righting than taller limpets which we hypothesise is related to increased energy requirements of flat limpets, which have to turn through a greater angle to right than tall limpets. Of the factors that cause morphological plasticity of gastropod shells, iceberg disturbance is the most likely cause of the sub-tidal gradient in N. concinna shell shape, and therefore the thermal limit for righting of limpets from 6 to 30 m depth, rather than environmental temperature. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.last_img read more

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The effect of acclimation temperature on thermal activity thresholds in polar terrestrial invertebrates

first_imgIn the Maritime Antarctic and High Arctic, soil microhabitat temperatures throughout the year typically range between -10 and +5°C. However, on occasion, they can exceed 20°C, and these instances are likely to increase and intensify as a result of climate warming. Remaining active under both cool and warm conditions is therefore important for polar terrestrial invertebrates if they are to forage, reproduce and maximise their fitness. In the current study, lower and upper thermal activity thresholds were investigated in the polar Collembola, Megaphorura arctica and Cryptopygus antarcticus, and the mite, Alaskozetes antarcticus. Specifically, the effect of acclimation on these traits was explored. Sub-zero activity was exhibited in all three species, at temperatures as low as -4.6°C in A. antarcticus. At high temperatures, all three species had capacity for activity above 30°C and were most active at 25°C. This indicates a comparable spread of temperatures across which activity can occur to that seen in temperate and tropical species, but with the activity window shifted towards lower temperatures. In all three species following one month acclimation at -2°C, the chill coma (= the temperature at which movement and activity cease) and critical thermal minimum (= low temperature at which coordination is no longer shown) occurred at lower temperatures than for individuals maintained at +4°C (except for the CTmin of M. arctica). Individuals acclimated at +10°C conversely showed little change in their chill coma or CTmin. A similar trend was demonstrated for the heat coma and critical thermal maximum (CTmax) of all species. Following one month at -2°C, the heat coma and CTmax were reduced as compared with +4°C reared individuals, whereas the heat coma and CTmax of individuals acclimated at +10°C showed little adjustment. The data obtained suggest these invertebrates are able to take maximum advantage of the short growing season and have some capacity, in spite of limited plasticity at high temperatures, to cope with climate change.last_img read more

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Multifrequency Radar Imagery and Characterization of Hazardous and Noxious Substances at Sea

first_imgThe increase in maritime traffic, particularly the transport of hazardous and noxious substances (HNSs), requires advanced methods of identification and characterization in environmental chemical spills. Knowledge about HNS monitoring using radar remote sensing is not as extensive as for oil spills; however, any progress on this issue would likely advance the monitoring of both chemical and oil-related incidents. To address the need for HNS monitoring, an experiment was conducted in May 2015 over the Mediterranean Sea during which controlled releases of HNS were imaged by a multifrequency radar system. The aim of this experiment was to establish a procedure for collecting evidence of illegal maritime pollution by noxious liquid substances using airborne radar sensors. In this paper, we demonstrate the ability of radar imagery to detect and characterize chemicals at sea. A normalized polarization difference parameter is introduced to quantify both the impacts of released product on the ocean surface and the relative concentration of the substance within the spill. We show that radar imagery can provide knowledge of the involved HNS. In particular, one can distinguish a product that forms a film on the top of the sea surface from another that mixes with seawater, the information that is critical for efficient cleanup operations.last_img read more

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Antarctic climate variability on regional and continental scales over the last 2000 years

first_imgClimate trends in the Antarctic region remain poorly characterized, owing to the brevity and scarcity of direct climate observations and the large magnitude of interannual to decadal-scale climate variability. Here, within the framework of the PAGES Antarctica2k working group, we build an enlarged database of ice core water stable isotope records from Antarctica, consisting of 112 records. We produce both unweighted and weighted isotopic (δ18O) composites and temperature reconstructions since 0 CE, binned at 5- and 10-year resolution, for seven climatically distinct regions covering the Antarctic continent. Following earlier work of the Antarctica2k working group, we also produce composites and reconstructions for the broader regions of East Antarctica, West Antarctica and the whole continent. We use three methods for our temperature reconstructions: (i) a temperature scaling based on the δ18O–temperature relationship output from an ECHAM5-wiso model simulation nudged to ERA-Interim atmospheric reanalyses from 1979 to 2013, and adjusted for the West Antarctic Ice Sheet region to borehole temperature data, (ii) a temperature scaling of the isotopic normalized anomalies to the variance of the regional reanalysis temperature and (iii) a composite-plus-scaling approach used in a previous continent-scale reconstruction of Antarctic temperature since 1 CE but applied to the new Antarctic ice core database. Our new reconstructions confirm a significant cooling trend from 0 to 1900 CE across all Antarctic regions where records extend back into the 1st millennium, with the exception of the Wilkes Land coast and Weddell Sea coast regions. Within this long-term cooling trend from 0 to 1900 CE, we find that the warmest period occurs between 300 and 1000 CE, and the coldest interval occurs from 1200 to 1900 CE. Since 1900 CE, significant warming trends are identified for the West Antarctic Ice Sheet, the Dronning Maud Land coast and the Antarctic Peninsula regions, and these trends are robust across the distribution of records that contribute to the unweighted isotopic composites and also significant in the weighted temperature reconstructions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of natural variability over the last 2000 years. However, projected warming of the Antarctic continent during the 21st century may soon see significant and unusual warming develop across other parts of the Antarctic continent. The extended Antarctica2k ice core isotope database developed by this working group opens up many avenues for developing a deeper understanding of the response of Antarctic climate to natural and anthropogenic climate forcings. The first long-term quantification of regional climate in Antarctica presented herein is a basis for data–model comparison and assessments of past, present and future driving factors of Antarctic climate.last_img read more

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How will vessels be inspected to meet emerging biofouling regulations for the prevention of marine invasions?

first_imgInternational and national guidelines and regulations to limit the inadvertent transfer of non-native species on the submergedsurfaces of vessels and mobile infrastructure are progressing. However, methods to assess compliance must be developed toassist both regulators and industry. While there is a history of biofouling inspections in maritime industries, includingcommercial shipping and infrastructure, such surveys are tailored for vessel safety and performance rather than being drivenby biosecurity purposes. Thus, these inspections are likely inadequate for confirming compliance with biosecurity regulations. Todetermine regulatory compliance, agencies will likely rely on a combination of risk profiling, assessment of documentation ofbiofouling management, archival data and images, and real-time in-water surveys made by divers or remotely operatedvehicles (ROVs) specific to biosecurity regulations. Divers may exceed ROVs at finding organisms in recesses and othertopographically complex areas, and when regulations require confirmation of species identity or viability. In contrast, ROVsmay be well suited for regulations that establish upper thresholds on biofouling levels with little concern for organismidentity or condition. Several factors will inform how a survey is conducted, including cost, the type of data required byregulations, environmental conditions, safety, and logistics. Survey designs and requirements should be transparent tomanage industry’s expectations of border procedures, to increase the efficiency with which industry and agencies managebiofouling and potentially align the evaluation of best practices in hull and niche area maintenance across jurisdictions.last_img read more

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Utah Men’s Swimming and Diving Team Honored By CSCAA

first_img Brad James FacebookTwitterLinkedInEmailSALT LAKE CITY-Tuesday, Utah men’s swimming and diving was selected as a Scholar All-American Team.The Utah men’s team had a 3.11 GPA, ranking third among Pac-12 schools.Furthermore, the Utes had six student-athletes named to the Pac-12’s all-academic first team earlier this year, the most in the conference.First-team honorees included senior fly Ben Scott of Steilacoom, Wash., senior distance free Brandon Shreeve of Corvallis, Ore., Daniel Theriault, a junior diver out of Winnipeg, Manitoba, Canada, sophomore distance free/breast Brody Lewis of Greeley, Colo., sophomore distance free Matteo Sogne of Modena, Italy, and sophomore back/breast/free/IM Jeremy Young of Casper, Wyo.Making the second team were senior breast Jack Burton of Ringwood, England, junior free/fly/M Austin Phillips of Centennial, Ohio, senior fly Chris Taber of Rancho Santa, Calif., and sophomore free Rahiti De Vos of Nice, France.This award is presented twice annually, once in the fall semester and again in the spring, to recognize teams achieving a 3.0 GPA during the semester. June 19, 2018 /Sports News – Local Utah Men’s Swimming and Diving Team Honored By CSCAA Written by Tags: Austin Phillips/Ben Scott/Brandon Shreeve/Brody Lewis/Chris Taber/Daniel Theriault/Jack Burton/Jeremy Young/Matteo Sogne/Rahiti De Vos/Utah Scholar All-America Teamlast_img read more

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University of Utah Men’s Basketball Has Pac-12 Season Pairings Announced

first_img FacebookTwitterLinkedInEmailSALT LAKE CITY-Monday, the Pac-12 conference released the weekly matchups and site designations for the league’s 2019-20 men’s basketball season.The University of Utah will commence their conference season January 1-5 by hosting Oregon and Oregon State.From January 8-12, the Utes will visit Colorado and Arizona-Arizona State between January 15-19. Between January 22-26, the Utes host Washington/Washington State. Between January 29-February 2, the Utes will play at UCLA/Utah. Between February 5-9, the Utes will host California/Stanford. Between February 12-16, the Utes will host Oregon/Oregon State. Between February 19-23, Utah will host UCLA/USC. Between February 26-March 1, the Utes will visit California/Stanford. Between March 4-7, the Utes will host Colorado.Official dates, broadcast networks and tip-off times will be revealed later this summer. Brad James July 22, 2019 /Sports News – Local University of Utah Men’s Basketball Has Pac-12 Season Pairings Announced Tags: broadcast schedules/conference pairings/Pac-12/Utah Men’s Basketball Written bylast_img read more

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Prep Sports Roundup: 10/8

first_img FacebookTwitterLinkedInEmailGirls Soccer2-A SouthBEAVER, Utah-Laci Sissener amassed a hat trick and the Parowan Rams pounded the Beaver Beavers 11-0 Tuesday in 2-A South girls soccer action. Brooklyn Hulet and Marissa Gale combined on the shutout for the Rams.Region 14NEPHI, Utah-Ally Squire and Brynlee Golding each scored as the Manti Templars doubled up Juab 2-1 in Region 14 girls soccer action Tuesday. Marissa Hall scored in the loss for the Wasps.DELTA, Utah-Savannah Nielson posted the sole goal of the match as the Delta Rabbits blanked North Sanpete 1-0 Tuesday in Region 14 girls soccer action. Haylee Christensen posted the shutout for the Rabbits.VolleyballRegion 12MONROE, Utah-The South Sevier Rams smacked Carbon 3-1 in Region 12 volleyball action Tuesday. The Rams prevailed 25-12, 13-25, 25-22 and 25-23 to overpower the Dinos.Region 14NEPHI, Utah-The Juab Wasps outlasted Manti 3-0 Tuesday in Region 14 volleyball action. The Wasps earned wins of 25-23, 25-17 and 25-21 to best the Templars in straight sets.DELTA, Utah-The Delta Rabbits routed Maeser Prep 3-0 in Region 14 volleyball action Tuesday at the Palladium. The Rabbits routed the Lions 25-10, 25-20 and 25-18 to get the straight sets win over the Lions.Region 16COALVILLE, Utah-The North Summit Braves routed Gunnison Valley 3-0 in Region 16 volleyball action Tuesday. The Braves prevailed over the Bulldogs 25-17, 25-18 and 25-11 to earn the dominant straight sets victory.ALTAMONT, Utah-The Altamont Longhorns outlasted North Sevier 3-2 Tueday in Region 16 volleyball action. The Longhorns prevailed over the Wolves 9-25, 20-25, 25-23, 25-17 and 15-13 to get the hard-earned victory.Region 18KANAB, Utah-The Millard Eagles pounded Kanab 3-0 in Region 18 volleyball action Tuesday. The Eagles bested Kanab with wins of 25-17, 25-16 and 25-19 to get the straight sets win.Non-RegionMT. PLEASANT, Utah-The Richfield Wildcats went on the road and topped North Sanpete 3-0 in non-region volleyball action Tuesday.ESCALANTE, Utah-The Escalante Moquis knocked off Parowan 3-1 in non-region volleyball action Tuesday.Baseball1A State TournamentSPANISH FORK, Utah-Telos Academy topped Tintic 9-5 in the quarterfinals of the 1A baseball state tournament Tuesday at Nelson Field in Spanish Fork. Telos now advances to the semifinals and will play Panguitch at 12:30 pm Friday at Dixie State University.SPANISH FORK, Utah-The Panguitch Bobcats earned the upset over Valley 7-0 Tuesday in the quarterfinals of the 1A baseball state tournament in Spanish Fork. The Bobcats now advance to play Telos at 12:30 pm Friday at Dixie State University.SPANISH FORK, Utah-The Piute Thunderbirds knocked off the higher seeded Diamond Ranch 7-2 Tuesday in the quarterfinals of the 1A baseball state tournament in Spanish Fork. Piute advances to play Wayne in the semifinals at 10:00 am Friday at Dixie State University.SPANISH FORK, Utah-The top-seeded Wayne Badgers came from behind in extra innings to beat Tabiona 10-9 in the the quarterfinals of the 1A baseball state tournament. Hunter Batty, Daniel Ayala and Dallas Failner all doubled in the win for the Badgers as they earned the victory with 2 runs in the 8th inning. The Badgers will now play Piute in the semifinals at 10:00 am Friday at Dixie State University. Tags: prep sports Written by October 8, 2019 /Sports News – Local Prep Sports Roundup: 10/8 Brad Jameslast_img read more

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UVU Men’s Basketball Visits Seattle U. Saturday Evening

first_img Tags: Seattle U. Men’s Basketball/UVU Men’s Basketball Brad James FacebookTwitterLinkedInEmailSEATTLE-Saturday evening, Utah Valley men’s basketball (7-10, 1-1 in WAC play) continues conference play by visiting the Seattle U. Redhawks (8-9, 1-1 in WAC play) at the Redhawk Center.Under new head coach Mark Madsen (7-10, .412) the Wolverines are in the mix in the WAC, tied for fourth place in the conference standings.UVU scores 71.5 points per game as the Wolverines rank 193rd nationally in scoring offense.Junior guard Isaiah White leads UVU in both scoring (15.8 points per game) and rebounding (8.9 boards per game).Senior guard TJ Washington (13.5 points per game, a team-best 50 assists), redshirt junior guard Brandon Averette (13.4 points per game) and redshirt junior guard-forward Casdon Jardine (11.2 points per game) also score in double figures on-average for the Wolverines.Junior guard Jamison Overton leads UVU with 17 steals on the season.Senior forward Emmanuel Olojakpoke has 47 blocked shots on the season, tying him for 8th nationally with Seton Hall’s Romaro Gill.Olojakpoke’s 2.76 blocks per game ranks him 18th nationally. By virtue of his skills, the Wolverines are sixth nationally in blocked shots (96) and 15th in blocked shots per game (5.6).The Wolverines surrender 70.2 points per game, ranking them 209th nationally in scoring defense.Seattle U. is coached by Jim Hayford who is 46-38 (.548) in his third season at Seattle U. He is 152-129 (.541) as a collegiate head coach, having coached six seasons at Eastern Washington (106-91, .538) as well.The Redhawks score 72.6 points per game, ranking them 156th nationally in scoring offense.Redshirt junior guard Terrell Brown is Seattle U.’s overall statistical leader.Brown leads the Redhawks in scoring (20.3 points per game), is tied for the team lead in rebounding with redshirt senior Myles Carter (7.1 boards per game for each) and deadlocked for the team lead in steals with senior guard Morgan Means (20 apiece). He also leads the team in assists with 69.Means (10.8 points per game) and Carter (10 points per game) also score in double figures on-average for Seattle U. Carter also leads the Redhawks in blocked shots with 21.Seattle U. surrenders 71.4 points per game, tying the Redhawks for 230th nationally in scoring defense with Hofstra.The Wolverines lead Seattle U. 10-9 all-time in this series. Written by January 9, 2020 /Sports News – Local UVU Men’s Basketball Visits Seattle U. Saturday Eveninglast_img read more

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