Providing expert scientific advice on the Antarctic environment [editorial]

first_imgIt is hard to divorce most human activities, including science, completely from politics. Politics is about perceived certainty whilst science is about doubt – they make strange bedfellows. Politicians detest probabilities whilst scientists abhor the absolute. Nowhere is the relationship between politics and science more publicly developed than in the Antarctic Treaty System. In the only continent devoted to peace and science it might be supposed that, after more than thirty years, the role of science would be both more robust and more pivotal in decision-making than elsewhere in the world. So it appears at present but will it remain so?last_img read more

Maternal investment in Antarctic fur seals: evidence for equality in the sexes?

first_imgStudies of the otariids (fur seals and sea lions), a highly sexually dimorphic group, have provided conflicting evidence of differential maternal expenditure in male and female offspring and, thus, suggestions that they conform to predictions of investment theory are equivocal. Since the mid-1970s, a diversity of research on Antarctic fur seals (Arctocephalus gazella) including studies of their reproductive ecology, lactation energetics, and foraging behaviour have been conducted at Bird Island, South Georgia that have resulted in one of the more complete and diverse data sets for any species of otariid. These long-term data were reviewed to determine whether there was any evidence to support that differential maternal expenditure occurred in Antarctic fur seals. Most of the data examined were collected during five consecutive austral summers from 1988 through 1992 and included years in which local food resources were abundant and scarce. We were unable to detect differences in the sex ratios of pups at birth or sex-biased differences in growth rates estimated from serial data, the number of foraging trips made, the duration of attendance ashore, diving behaviour, suckling behaviour, or milk consumption in any year and in the duration of foraging trips or age at weaning in 2 of 3 years. In addition, we found no evidence of greater reproductive costs between mothers with sons or daughters relative to their reproductive performance the following year. In contrast, sex-biased differences were only found in the duration of foraging trips in 1990, the age at weaning in 1988, and consistently in growth rates estimated from cross-sectional data. We suggest that differential maternal expenditure does not occur in Antarctic fur seals because male pups probably do not gain greater benefit from additional maternal expenditure than female pups. After weaning, males experience a period of rapid juvenile growth over 3–4 years during which time body mass nearly trebles. This growth will almost certainly be dependent upon available food resources then rather than on any maternal expenditure received over the first 4 months of life and, thus, the assumptions of the Trivers and Willard hypothesis are probably invalid for Antarctic fur seals.last_img read more

The significance of the moult cycle to cold tolerance in the Antarctic collembolan Cryptopygus antarcticus

first_imgResearch into the ecophysiology of arthropod cold tolerance has largely focussed on those parts of the year and/or the life cycle in which cold stress is most likely to be experienced, resulting in an emphasis on studies of the preparation for and survival in the over-wintering state. However, the non-feeding stage of the moult cycle also gives rise to a period of increased cold hardiness in some microarthropods and, as a consequence, a proportion of the field population is cold tolerant even during the summer active period. In the case of the common Antarctic springtail Cryptopygus antarcticus, the proportion of time spent in this non-feeding stage is extended disproportionately relative to the feeding stage as temperature is reduced. As a result, the proportion of the population in a cold tolerant state, with low supercooling points (SCPs), increases at lower temperatures. We found that, at 5 degrees C, about 37% of the population are involved in ecdysis and exhibit low SCPs. At 2 degrees C this figure increased to 50% and, at 0 degrees C, we estimate that 80% of the population will have increased cold hardiness as a result of a prolonged non-feeding, premoult period. Thus, as part of the suite of life history and ecophysiological features that enable this Antarctic springtail to survive in its hostile environment, it appears that it can take advantage of and extend the use of a pre-existing characteristic inherent within the moulting cycle.last_img read more

Chemical weathering and solute export by meltwater in a maritime Antarctic glacier basin

first_imgSolute yields, laboratory dissolution data and both chemical and isotopic markers of rock weathering reactions are used to characterise the biogeochemistry of glacial meltwaters draining a maritime Antarctic glacier. We find that delayed flowpaths through ice-marginal talus and moraine sediments are critical for the acquisition of solute from rock minerals because delayed flowpaths through subglacial sediments are absent beneath this small, cold-based glacier. Here the mechanisms of weathering are similar to those reported in subglacial environments, and include sub-oxic conditions in the early summer and increasingly oxic conditions thereafter. Up to 85% of the NO3 − and 65% of the SO4 2− are most likely produced by bacterially mediated reactions in these ice marginal sediments. However, reactive pyrite phases are sparse in the host rocks, limiting the export of Fe, SO4 2− and cations that may be removed by weathering once pyrite oxidation has taken place. This means that dissolution of Ca2+ and Na+ from carbonate and silicate minerals dominate, producing moderate cationic denudation yields from Tuva Glacier (163 Σ*meq+ m−2 a−1) compared to a global range of values (94–4,200 Σ*meq+ km−2 a−1). Overall, crustally derived cations represent 42% of the total cationic flux, the rest being accounted for by snowpack sources.last_img read more

Semiautomated detection and mapping of vegetation distribution in the Antarctic environment using spatial-spectral characteristics of WorldView-2 imagery.

first_imgEffective monitoring of changes in the geographic distribution of cryospheric vegetation requires high-resolution and accurate baseline maps. The rationale of the present study is to compare multiple feature extraction approaches to remotely mapping vegetation in Antarctica, assessing which give the greatest accuracy and reproducibility relative to those currently available. This study provides precise, high-resolution, and refined baseline information on vegetation distribution as is required to enable future spatiotemporal change analyses of the vegetation in Antarctica. We designed and implemented a semiautomated customized normalized difference vegetation index (NDVI) approach for extracting cryospheric vegetation by incorporating very high resolution (VHR) 8-band WorldView-2 (WV-2) satellite data. The viability of state-of-the-art target detection, spectral processing/matching, and pixel-wise supervised classification feature extraction techniques are compared with the customized NDVI approach devised in this study. An extensive quantitative and comparative assessment was made by evaluating four semiautomatic feature extraction approaches consisting of 16 feature extraction standalone methods (four customized NDVI plus 12 existing methods) for mapping vegetation on Fisher Island and Stornes Peninsula in the Larsemann Hills, situated on continental east Antarctica. The results indicated that the customized NDVI approach achieved superior performance (average bias error ranged from ~6.44 ± 1.34% to ~11.55 ± 1.34%) and highest statistical stability in terms of performance when compared with existing feature extraction approaches. Overall, the accuracy analysis of the vegetation mapping relative to manually digitized reference data (supplemented by validation with ground truthing) indicated that the 16 semi-automatic mapping methods representing four general feature extraction approaches extracted vegetated area from Fisher Island and Stornes Peninsula totalling between 2.38 and 3.72 km2 (2.85 ± 0.10 km2 on average) with bias values ranging from 3.49 to 31.39% (average 12.81 ± 1.88%) and average root mean square error (RMSE) of 0.41 km2 (14.73 ± 1.88%). Further, the robustness of the analyses and results were endorsed by a cross-validation experiment conducted to map vegetation from the Schirmacher Oasis, East Antarctica. Based on the robust comparative analysis of these 16 methods, vegetation maps of the Larsemann Hills and Schirmacher Oasis were derived by ensemble merging of the five top-performing methods (Mixture Tuned Matched Filtering, Matched Filtering, Matched Filtering/Spectral Angle Mapper Ratio, NDVI-2, and NDVI-4). This study is the first of its kind to detect and map sparse and isolated vegetated patches (with smallest area of 0.25 m2) in East Antarctica using VHR data and to use ensemble merging of feature extraction methods, and provides access to an important indicator for environmental change.last_img read more

Hale, Wood selected First Team All-WCC

first_imgMay 22, 2018 /Sports News – Local Hale, Wood selected First Team All-WCC FacebookTwitterLinkedInEmailSAN BRUNO, Calif.—Juniors Brock Hale and Jordan Wood of BYU baseball were selected to the 13-member All-West Coast Conference First Team.Hale and Wood were the only Cougars named to any of the All-WCC honors announced on Tuesday. These teams and major award winners were voted on solely by the league’s 10 head coaches.Hale, an outfielder from Mesa, Arizona, started all 50 games and topped the WCC in batting average and slugging for most of the season.  Hale led BYU in most offensive categories: .342 batting average, 40 runs, 67 hits, 15 doubles, 8 homers, 31 RBI, 108 total bases, .551 slugging, .425 on-base percentage and 7 of 9 stolen bases.Hale committed only one error in 101 chances, including three assists. He was Rawlings WCC Player of the Week vs. Auburn in the first week of March. He batted .408 in the month of March when he had a slugging average of .789. Hale batted .400 in WCC games only with a .545 slugging percentage.Wood, a right-handed pitcher from Friendswood, Texas, started 13 games and his 2.66 earned run average was fourth best in the WCC.  He posted a 5-4 record with a complete game in an 8-1 win against Omaha when he struck out nine batters.Wood was one batter shy of a complete game last week in the 3-1 win against Pacific in the short contest that lasted one hour and 55 minutes. Wood also registered victories against Gonzaga, San Diego and San Francisco and was the victim of four one-run losses.​ Tags: Baseball/Brock Hale/BYU Cougars/Jordan Wood/WCC Robert Lovell Written bylast_img read more

Three Dixie State Stars Are Named As Pac-West Scholar Athletes of the Year

first_img FacebookTwitterLinkedInEmailST. GEORGE, Utah-In a few weeks, Dixie State’s athletic department officially leaves the Pac-West Conference to join the football program in the Rocky Mountain Athletic Conference.With that said, three Trailblazers athletes have left the Pac-West on the right note, as the conference’s best scholar athlete in their respective sports.These stars include sophomore men’s golfer Jayce Frampton, senior women’s soccer player Darian Murdock and men’s basketball player Brandon Simister as confirmed by the Pac-West Tuesday.Frampton, a native of Centerville, Utah and a product of Viewmont High School of Bountiful, earned 2017-18 second-team all-Pac West honors after earning two individual event victories in Hawaii during the fall season. He is the owner of a 3.74 GPA while majoring in finance at Dixie State University.Murdock has graduated with a 3.98 GPA in nursing and is a native of Herriman, Utah and graduate of Herriman High School. Her stellar senior season was capped off with a second-straight CoSIDA Academic All-America second team selection.In 2017, she repeated as the Pac-West’s women’s soccer player of the year, earning D2CCA West region player of the year and D2CCA second-team All-American honors.Murdock ends her four year career with the Trailblazers as the program’s leader in game-winning goals (16) and finished third all-time in goals (42) career points (94), career shots (204) and career shots on goal (104).Simister, a native of St. George and a graduate of Desert Hills High School, earned CoSIDA second-team academic All-American honors last March and became a three-time CoSIDA academic all-district 8 selection with a 3.91 GPA in biology. He was a first-team all-Pac West and second-team D2CCA all-West region selection this past season after finishing as Dixie State’s leading scorer at 15.1 points per game. June 19, 2018 /Sports News – Local Three Dixie State Stars Are Named As Pac-West Scholar Athletes of the Year Tags: Brandon Simister/Darian Murdock/Dixie State/Jayce Frampton/Pac-West/Rocky Mountain Athletic Conference Written by Brad Jameslast_img read more

Grizzlies acquire Justin Holiday from Bulls in trade

first_img FacebookTwitterLinkedInEmailTim Warner/Getty Images(MEMPHIS, Tenn.) — The Memphis Grizzlies have acquired Justin Holiday from the Chicago Bulls, the team announced late Thursday.In exchange for the 29-year-old guard, Memphis sent guard MarShon Brooks and guard/forward Wayne Selden Jr. to Chicago. The Grizzlies also gave up two future second round draft picks to the Bulls.This season with Chicago, Holiday has started in every game in which he’s appeared. He’s averaged 11.6 points, 4.4 rebounds and 2.2 assists.Copyright © 2019, ABC Radio. All rights reserved. Written by January 4, 2019 /Sports News – National Grizzlies acquire Justin Holiday from Bulls in tradecenter_img Beau Lundlast_img read more

Weber State’s Iosua Opeta Selected for NFLPA Collegiate Bowl

first_imgJanuary 17, 2019 /Sports News – Local Weber State’s Iosua Opeta Selected for NFLPA Collegiate Bowl FacebookTwitterLinkedInEmailOGDEN, Utah-Thursday, offensive lineman Iosua Opeta, formerly of Weber State football was selected to play in the NFLPA Collegiate Bowl. All 32 NFL teams will be in attendance as well as nearly 200 scouts, player personnel staff, general managers and head coaches. This postseason all-star game is in its eighth year of existence and features some of the best seniors in college football. Tags: Iosua Opeta/Mike Tice/NFLPA Collegiate Bowl/Rose Bowl/Weber State Football Opeta was part of the winningest senior class in Weber State history and he graduated in December with a degree in human performance management. Written by The game will be played Saturday January 19 at the Rose Bowl in Pasadena, Calif. Opeta will compete for the National Team coached by Mike Tice, a former head coach with the Minnesota Vikings. Opeta ended his Weber State career as a 2-time All-American and started each game over the course of his last three seasons for the Wildcats. Brad Jameslast_img read more

Toronto Maple Leafs sign Auston Matthews to second-richest NHL contract

first_img Beau Lund FacebookTwitterLinkedInEmailPhoto by Phil Ellsworth / ESPN Images(TORONTO) — The Toronto Maple Leafs made 21-year-old star Auston Matthews one of the highest paid NHL players ever with a new five-year contract announced on Tuesday. The deal keeps Matthews in Toronto through the 2023-2024 season, for a reported $58.17 million. He would have been a restricted free agent after the current season.Matthews’ $11.634 million per year is behind only Edmonton Oilers star Connor McDavid, who makes $12.5 million per season. The Maple Leafs also have the third richest contract in center John Tavares, who makes $11 million each year.With 23 goals and 23 assists in his team’s first 38 games, Matthews has lived up to the hype that has surrounded him since before he was the number one overall draft pick in 2016. He is already a three-time All-Star, scoring 40 goals in his rookie campaign, and 34 in just 62 games last season.Copyright © 2019, ABC Radio. All rights reserved. Written bycenter_img February 5, 2019 /Sports News – National Toronto Maple Leafs sign Auston Matthews to second-richest NHL contractlast_img read more