A new Late Middle Cambrian paleomagnetic pole for the Ellsworth Mountains, Antarctica

first_imgA paleomagnetic study of the late Middle to possibly early Late Cambrian Liberty Hills Formation in the Ellsworth Mountains, Antarctica, reveals a stable magnetization with positive fold and reversal tests. The paleopole is based on 16 sites from volcanic and sedimentary rocks and lies at lat 7.3°N and long 326.3°E ( $mathrm{A},_{95}=6.0^{circ }$ ). The new paleomagnetic data support the view that the Ellsworth Mountains are part of a microplate—the Ellsworth‐Whitmore Mountains crustal block—that rotated independently of the main Gondwana continental blocks during breakup. The Liberty Hills pole differs from both previous poles recovered from Cambrian rocks in the Ellsworth Mountains and from the available Gondwana reference pole data. Our pole indicates a more northerly prebreakup position for the Ellsworth Mountains than previously suggested, contradicting the overwhelming geologic evidence for a prebreakup position close to southern Africa. The reasons for this are uncertain, but we suggest that problems with the Gondwana apparent polar wander path may be important. More well constrained, early Paleozoic paleomagnetic data are required from the Ellsworth Mountains and the Gondwana continents if the data are to constrain further the Middle‐Late Cambrian location of the Ellsworth‐Whitmore Mountains block.last_img read more

Throwing light on straddling stocks of Illex argentinus: assessing fishing intensity with satellite imagery

first_imgMarine fisheries provide around 20% of animal protein consumed by man worldwide, but ineffectivemanagement can lead to commercial extinction of exploited stocks. Fisheries that overlap nationally controlled and highseas waters cause particular problems, as few management data are available for the high seas. The Argentinean shortfinnedsquid, Illex argentinus, exemplifies such a “straddling stock”. Here we demonstrate that light emitted by fishingvessels to attract squid can be detected via remote-sensing. Unlike conventional fisheries data, which are restricted bypolitical boundaries, satellite imagery can provide a synoptic view of fishing activity in both regulated and unregulatedareas. By using known levels of fishing effort in Falkland Islands waters to calibrate the images, we are able toestimate effort levels on the high seas, providing a more comprehensive analysis of the overall impact of fishing on thestock. This innovative tool for quantifying fishing activity across management boundaries has wide-ranging applicationsto squid fisheries worldwide.last_img read more

Interactions between climate, vegetation and the active layer in soils at two Maritime Antarctic sites

first_imgIn the summer 2000–01, thermal monitoring of the permafrost active layer within variousterrestrial sites covered by lichen, moss or grasses was undertaken at Jubany (King George Island) and SignyIsland in the Maritime Antarctic. The results demonstrated the buffering effect of vegetation on groundsurface temperature (GST) and the relationship between vegetation and active layer thickness. Vegetationtype and coverage influenced the GST in both locations with highest variations and values in theDeschampsia and Usnea sites and the lowest variations and values in the Jubany moss site. Active layerthickness ranged from 57 cm (Jubany moss site) to 227 cm (Signy Deschampsia site). Active layer thicknessdata from Signy were compared with data collected at the same location four decades earlier. Using aregression equation for air temperature versus ground surface temperatures the patterns of changing airtemperature over time suggest that the active layer thickness increased c. 30 cm between 1963 and 1990 andthen decreased 30 cm between 1990 and 2000. The documented increased rate of warming (2°C ± 1) since1950 for air temperatures recorded in the South Orkney Islands suggests that the overall trend of active layerthickness increase will be around 1 cm year-1.last_img read more

A review of surface ozone in the polar regions

first_imgSurface ozone records from ten polar research stations were investigated for the dependencies of ozone on radiative processes, snow-photochemisty, and synoptic and stratospheric transport. A total of 146 annual data records for the Arctic sites Barrow, Alaska; Summit, Greenland; Alert, Canada; Zeppelinfjellet, Norway; and the Antarctic stations Halley, McMurdo, Neumayer, Sanae, Syowa, and South Pole were analyzed. Mean ozone at the Northern Hemisphere (NH) stations (excluding Summit) is 5 ppbv higher than in Antarctica. Statistical analysis yielded best estimates for the projected year 2005 median annual ozone mixing ratios, which for the Arctic stations were 33.5 ppbv at Alert, 28.6 ppbv at Barrow, 46.3 ppbv ppb at Summit and 33.7 ppbv at Zeppelinfjellet. For the Antarctic stations the corresponding ozone mixing ratios were 21.6 ppbv at Halley, 27.0 ppbv at McMurdo, 24.9 ppbv at Neumayer, 27.2 ppbv at Sanae, 29.4 ppbv at South Pole, and 25.8 ppbv at Syowa. At both Summit (3212 m asl) and South Pole (2830 m asl), annual mean ozone is higher than at the lower elevation and coastal stations. A trend analysis revealed that all sites in recent years have experienced low to moderate increases in surface ozone ranging from 0.02 to 0.26 ppbv yr−1, albeit none of these changes were found to be statistically significant trends. A seasonal trend analysis showed above-average increases in ozone during the spring and early summer periods for both Arctic (Alert, Zeppelinfjellet) and Antarctic (McMurdo, Neumayer, South Pole) sites. In contrast, at Barrow, springtime ozone has been declining. All coastal stations experience springtime episodes with rapid depletion of ozone in the boundary layer, attributable to photochemically catalyzed ozone depletion from halogen chemistry. This effect is most obvious at Barrow, followed by Alert. Springtime depletion episodes are less pronounced at Antarctic stations. At South Pole, during the Antarctic spring and summer, photochemical ozone production yields frequent episodes with enhanced surface ozone. Other Antarctic stations show similar, though less frequent spring and summertime periods with enhanced ozone. The Antarctic data provide evidence that austral spring and summertime ozone production in Antarctica is widespread, respectively, affects all stations at least through transport events. This ozone production contributes to a several ppbv enhancement in the annual mean ozone over the Antarctic plateau; however, it is not the determining process in the Antarctic seasonal ozone cycle. Although Summit and South Pole have many similarities in their environmental conditions, this ozone production does not appear to be of equal importance at Summit. Amplitudes of diurnal, summertime ozone cycles at these polar sites are weaker than at lower latitude locations. Amplitudes of seasonal ozone changes are larger in the Southern Hemisphere (by 5 ppbv), most likely due to less summertime photochemical ozone loss and more transport of ozone-rich air to the Arctic during the NH spring and summer months.last_img read more

Antarctic biology, the International Polar Year, and beyond

first_imgAs we draw towards the end of the massive effort that has been the International Polar Year (IPY), it is opportune to consider what impact it has had on Antarctic biological research and its research community. Have we seen or are we going to see major advances in any particular areas of science? Has the hoped-for international integration of research communities been advanced, including those of the ‘non-traditional’ or ‘less developed’ polar nations? Have the ‘global public’ become more engaged with the polar regions?last_img

Dynamics of seasonal movements by a trans-Pacific migrant, the Westland petrel

first_imgKnowledge of the dynamics of long-distance migrations of pelagic seabirds is limited. Recent advances in tracking technology have yielded detailed, continuous accounts of the movements of individual seabirds over large spatial and temporal scales. We studied the timing of migration and year-round distribution of the Westland Petrel (Procellaria westlandica), listed by the IUCN as vulnerable, with miniature archival light loggers (geolocators) deployed on 10 incubating birds breeding in 2007 at Westland, New Zealand. We retrieved data from eight Westland Petrels, indicating the birds migrated in November directly east 7000 km from the coast of New Zealand to South American waters in 6 days (range 47), then returned the following April in 10 days (range 813). The durations of an individual’s outward and return flights and the dates of its outward and return migrations were positively correlated. During their journeys east and west, birds spent on average (SD) 9.9% (9.7) and 17.2% (12.0), respectively, of their time on the water. There was also considerable variation in individuals’ foraging areas: while breeding, birds used three major coastal areas <1200 km from their colony; during the nonbreeding period, six birds remained off the south coast of Chile, while two others continued their migration through the Drake Passage to waters off southern Argentina. These results expand the known distribution of the species, identify new key foraging areas, and show patterns of outward and return migration behavior consistent in individuals.last_img read more

Contrasting strategies of resistance vs. tolerance to desiccationin two polar dipterans

first_imgLow water availability is one of the principal stressors for terrestrial invertebrates in the polar regions, determining the survival of individuals, the success of species and the composition of communities. The Arctic and Antarctic dipterans Heleomyza borealis and Eretmoptera murphyi spend the majority of their biennial life cycles as larvae, and so are exposed to the full range of environmental conditions, including low water availability, over the annual cycle. In the current study, the desiccation resistance and desiccation tolerance of larvae were investigated, as well as their capacity for cross-tolerance to temperature stress. Larvae of H. borealis showed high levels of desiccation resistance, only losing 6.9% of their body water after 12 days at 98.2% relative humidity (RH). In contrast, larvae of E. murphyi lost 46.7% of their body water after 12 days at the same RH. Survival of E. murphyi larvae remained high in spite of this loss (>80% survival). Following exposure to 98.2% RH, larvae of E. murphyi showed enhanced survival at −18°C for 2 h. The supercooling point of larvae of both species was also lowered following prior treatment at 98.2% RH. Cross-tolerance to high temperatures (37 or 38.5°C) was not noted following desiccation in E. murphyi, and survival even fell at 37°C following a 12-day pre-treatment. The current study demonstrates two different strategies of responding to low water availability in the polar regions and indicates the potential for cross-tolerance, a capacity which is likely to be beneficial in the ever-changing polar climate.last_img read more

Utah Baseball Wins Rubber Match 5-4 Against USC

first_imgApril 13, 2019 /Sports News – Local Utah Baseball Wins Rubber Match 5-4 Against USC Written by FacebookTwitterLinkedInEmailSALT LAKE CITY, Utah – Utah baseball earned the series win with a 5-4 victory over USC on Saturday, April 13 at Smith’s Ballpark in Salt Lake City, Utah.Erick Migueles had a monster game going 3-3 with three doubles and three RBI. Chase Fernlund and Oliver Dunn each had two hits on the day as well. In all, the top three batters in the lineup went a combined 7-10 on the afternoon and scored four of the five runs to help clinch the series over the Trojans.Utah once again got their bats going early scoring one run in the first inning to take the lead when Shea Kramer knocked in Dunn from third.USC tied up the game in the third, but Migueles’ second double of the game scored Fernlund and Dunn putting the Utes back up 3-1.The Trojans tied up the score in the fifth scoring one run in each of the fourth and fifth innings, but Migueles came through once again with a double to score Fernlund.Utah added an insurance run in the seventh and ended up needing it as USC threatened in the ninth, scoring one run, but Dustyn Schramm got the save pushing Utah to victory.Joshua Tedeschi got the win moving his record to 4-3 on the season. He pitched 6.2 innings and only allowed three runs on six hits. Schramm came in for Tedeschi and closed things out over the final 2.1 innings to earn his second save of the season.The win was the 10th of the season for the Utes and earned them their first Pac-12 series victory as they bounced back to win the final two games.Utah is three games in to a seven-game homestand and will be back at Smith’s Ballpark to host Utah Valley on Tuesday, April 16 at 6 p.m.   Tags: Pac 12/Utah Utes Baseball Robert Lovelllast_img read more

Bees postpone Monday’s game due to death of former pitcher Tyler Skaggs

first_img Written by FacebookTwitterLinkedInEmail(Southlake, TX) — Los Angeles Angels pitcher Tyler Skaggs is dead at the age of 27.Police in North Texas say Skaggs was discovered dead yesterday in a hotel where the team was staying ahead of their matchup against the Texas Rangers. The game was postponed.Foul play is not suspected, but the cause of death hasn’t been released.Skaggs made 11 starts for the Bees between 2014-and-2017.The Salt Lake Bees did not play yesterday’s scheduled game against the Tacoma Rainiers due to the death of Skaggs.The Bees will play a doubleheader tonight in Tacoma. They have split the first two of the five-game series with the Rainiers. Tags: Los Angeles Angels/Salt Lake Bees/Tyler Skaggs July 2, 2019 /Sports News – Local Bees postpone Monday’s game due to death of former pitcher Tyler Skaggs Robert Lovelllast_img read more

SUU Men’s Basketball Returns To Action Thursday Against Northern Arizona

first_img Tags: NAU Basketball/SUU Basketball Written by Brad James January 15, 2020 /Sports News – Local SUU Men’s Basketball Returns To Action Thursday Against Northern Arizona FacebookTwitterLinkedInEmailCEDAR CITY, Utah-Thursday, Southern Utah men’s basketball (10-5, 3-1 in Big Sky Conference action) hosts the Northern Arizona Lumberjacks  (7-7, 1-4 in Big Sky play) as the conference season ensues for both squads.SUU is currently tied for second place in the conference standings with Northern Colorado with Montana, at 5-1, currently leading the Big Sky standings.Thunderbirds head coach Todd Simon is 46-68 (.404) at the helm of the SUU program and is easily having his best season to date presently, his fourth campaign.The Thunderbirds score 74.5 points per game which ranks SUU 113th nationally in scoring offense.Junior guard John Knight III (13.2 points per game) is currently SUU’s leading scorer.Fellow double digit scorers on-average this season for the Thunderbirds include redshirt senior guard/forward Cameron Oluyitan (13.1 points, 5.1 rebounds per game, team-bests in assists [34] and steals [21]) and redshirt senior forward Dwayne Morgan (11.2 points per game).Sophomore guard Harrison Butler averages a team-best 7.7 rebounds per game and redshirt senior center, Senegalese national, Daouda (David) N’Diaye has a team-best 19 blocked shots.The Thunderbirds surrender 63.3 points per game, ranking them 57th nationally in scoring defense.SUU out-rebounds opponents by a +7.4 margin (25th nationally) per game (39.5-32.1 on-average on the glass).The Lumberjacks are coached by Shane Burcar (7-7, .500) who wends his way through his first season as a Division I men’s basketball head coach.Northern Arizona scores 72.1 points per game, ranking the Lumberjacks 169th nationally in scoring offense.Sophomore guard Cameron Shelton (12.9 points, 6.5 rebounds per game) is Northern Arizona’s leader in scoring and assists (56) on the season.Also scoring in double figures on-average for the Lumberjacks are senior forward Brooks DeBisschop (10.6 points, a team-best 7.5 rebounds on the season, tied for the team lead in steals [17] with junior guard Cameron Satterwhite and leading the squad in blocked shots with 10), senior guard Ted McCree (10.2 points per game) and redshirt sophomore guard Luke Avdalovic (10 points per game).The Lumberjacks surrender 67.6 points per game, ranking Northern Arizona 149th nationally in scoring defense.The Thunderbirds lead the series against Northern Arizona 14-13 all-time.last_img read more