Food and feeding ecology of Wilson’s storm petrel Oceanites oceanicusat South Georgia

first_imgAt South Georgia, the diet of Wilson’s storm petrel was studied using the regurgitates of adults arriving to feed chicks. Feeding frequency and meal size were estimated by weighing chicks twice daily, or in some cases every 3 h during daytime. Crustaceans contributed 98% of the total number of individual items and 68% of the total weight consumed; fish, 1% of the number of items and 28% of the weight. The most abundant crustacean was the amphipod Themisto gaudichaudii, which accounted for 90% of the total number but only 44% of the total weight of crustaceans eaten. Most (79%) of the Themisto were juveniles. Euphausiids were much less numerous in the diet (5% by number) but were the main group by weight (55%); most (52%) were Antarctic krill, with juveniles and sub‐adults (25–50 mm long) predominating. Mysids, copepods and barnacle larvae were also present. Fish were all myctophids (lanternfish), Protomyctophum normani and P. bolini being identified; specimens were 50–85 mm long and weighed 1–4 g. Meal sizes averaged 6‐5‐7‐5 g (14–22% adult body mass); about 75% of chicks were fed each day (mainly at night), about 10% probably receiving meals from both parents. A review of storm petrel diets emphasizes the importance of fish to Oceanodroma species and of crustaceans to Oceanites, Garrodia and Pelagodroma. Euphausiids and amphipods (chiefly Themisto and Hyperia) are the main crustacean prey and range from 5–50 mm and 0‐005‐0‐7 g. Myctophids are the main fish prey and range from 20–100 mm and 1–5 g. Meal size ranges from 15–25% adult body mass and chicks are fed on 50–85% of days. This low delivery rate is mainly responsible for the disproportionately slow growth and long fledging period of storm petrel chicks.last_img read more

Favored regions for chorus-driven electron acceleration to relativistic energies in the Earth’s outer radiation belt

first_img[1] Pitch angle and energy diffusion rates for scattering by whistler-mode chorus waves are proportional to the wave magnetic field intensity and are strongly dependent on the frequency distribution of the waves and to the ratio between the electron plasma frequency (f(pe)) and the electron gyrofrequency (f(ce)). Relativistic electrons interact most readily with lower-band chorus (0.1 < f/f(ce) 300 nT). Enhanced waves in these regions could play a major role in electron acceleration to relativistic energies during periods of prolonged substorm activity.last_img

Antarctic ice-shelf thickness from satellite radar altimetry

first_imgIce-shelf thickness is an important boundary condition for ice-sheet and sub-ice-shelf cavity modelling. It is required near the grounding line to calculate the ice flux used to determine ice-sheet mass balance by comparison with the upstream accumulation. In this mass budget approach, theaccuracy of the ice thickness is one of the limiting factors in the calculation. We present a satelliteretrieval of the ice thickness for all Antarctic ice shelves using satellite radar altimeter data from thegeodetic phases of the European Remote-sensing Satellite (ERS-1) during 1994–95 supplemented by ICESat data for regions south of the ERS-1 latitudinal limit. Surface elevations derived from these instruments are interpolated on to regular grids using kriging, and converted to ice thicknesses using a modelled firn-density correction. The availability of new spatial variable firn-density correctionsignificantly reduces the error in ice thickness as this was previously the dominant error source.Comparison to airborne data shows good agreement, particularly when compared to SOAR CASERTZdata on the largest ice shelves. Biases range from –13.0m for areas where the assumption of hydrostaticequilibrium breaks down, to 53.4m in regions where marine ice may be present.last_img read more

Bayesian Glaciological Modelling to quantify uncertainties in ice core chronologies

first_imgValuable information about the environment and climate of the past is preserved in ice cores which are drilled through ice sheets in polar and alpine regions. A pivotal part of interpreting the information held within the cores is to build ice core chronologies i.e. to relate time to depth. Existing dating methods can be categorised as follows: (1) layer counting using the seasonality in signals, (2) glaciological modelling describing processes such as snow accumulation and plastic deformation of ice, (3) comparison with other dated records, or (4) any combination of these. Conventionally, implementation of these approaches does not use statistical methods. In order to quantify dating uncertainties, in this paper we develop the approach of category (2) further. First, the sources of uncertainty involved in glaciological models are formalised. Feeding these into a statistical framework, that we call Bayesian Glaciological Modelling (BGM), allows us to demonstrate the effect that uncertainty in the glaciological model has on the chronology. BGM may also include additional information to constrain the resulting chronology, for example from layer counting or other dated records such as traces from volcanic eruptions.Our case study involves applying BGM to date an Antarctic ice core (a Dyer plateau core). Working through this example allows us to emphasise the importance of properly assessing uncertain elements in order to arrive at accurate chronologies, including valid dating uncertainties. Valid dating uncertainties, in turn, facilitate the interpretation of environmental and climatic conditions at the location of the ice core as well as the comparison and development of ice core chronologies from different locations.last_img read more

A horizon scan of global conservation issues for 2015

first_imgThis paper presents the results of our sixth annual horizon scan, which aims to identify phenomena that may have substantial effects on the global environment, but are not widely known or well understood. A group of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics via an iterative, Delphi-like process. The topics include a novel class of insecticide compounds, legalisation of recreational drugs, and the emergence of a new ecosystem associated with ice retreat in the Antarcticlast_img

A comparison of Antarctic ice sheet surface mass balance from atmospheric climate models and in situ observations

first_imgIn this study, 3265 multiyear averaged in situ observations and 29 observational records at annual time scale are used to examine the performance of recent reanalysis and regional atmospheric climate model products [ERA-Interim, JRA-55, MERRA, the Polar version of MM5 (PMM5), RACMO2.1, and RACMO2.3] for their spatial and interannual variability of Antarctic surface mass balance (SMB), respectively. Simulated precipitation seasonality is also evaluated using three in situ observations and model intercomparison. All products qualitatively capture the macroscale spatial variability of observed SMB, but it is not possible to rank their relative performance because of the sparse observations at coastal regions with an elevation range from 200 to 1000 m. In terms of the absolute amount of observed snow accumulation in interior Antarctica, RACMO2.3 fits best, while the other models either underestimate (JRA-55, MERRA, ERA-Interim, and RACMO2.1) or overestimate (PMM5) the accumulation. Despite underestimated precipitation by the three reanalyses and RACMO2.1, this feature is clearly improved in JRA-55. However, because of changes in the observing system, especially the dramatically increased satellite observations for data assimilation, JRA-55 presents a marked jump in snow accumulation around 1979 and a large increase after the late 1990s. Although precipitation seasonality over the whole ice sheet is common for all products, ERA-Interim provides an unrealistic estimate of precipitation seasonality on the East Antarctic plateau, with high precipitation strongly peaking in summer. ERA-Interim shows a significant correlation with interannual variability of observed snow accumulation measurements at 28 of 29 locations, whereas fewer than 20 site observations significantly correlate with simulations by the other models. This suggests that ERA-Interim exhibits the highest performance of interannual variability in the observed precipitationlast_img read more

Keirsey Has Five Hits as Utah Baseball Falls to Washington, 13-7

first_imgMay 19, 2018 /Sports News – Local Keirsey Has Five Hits as Utah Baseball Falls to Washington, 13-7 Tags: Baseball/Pac 12/Utah Utes Robert Lovell Written by FacebookTwitterLinkedInEmailSALT LAKE CITY – In what will likely be his final game at Smith’s Ballpark, junior DaShawn Keirsey, Jr., tied his career high with five hits as the Utah baseball team fell to Washington, 13-7, to close out the three-game series.Keirsey went 5-for-5 for the Utes, which included his league-leading 23rd double of the year. He also scored two runs. Rykker Tom went 2-for-4 with three RBI and a walk while Chandler Anderson also had two hits for the Utes.Senior Josh Lapiana earned the loss, allowing nine runs (eight earned) on 10 hits with four walks and four strikeouts. Austin Moore pitched 1 2/3 innings and did not allow a run. Riley Pierce, Trenton Stoltz and Spencer Johnson all made brief appearances on the mound.Both teams scored two runs in the first inning. Utah’s came on three-straight hits from Keirsey, Oliver Dunn and Tom, with Tom hitting a two-RBI double to right center. Washington added two runs in the second to take a 4-2 lead.Although the Huskies held a slight advantage throughout the game, the Utes came within a run several times. Chandler Anderson led off the fourth with an RBI triple and scored on a sacrifice fly to cut the lead to 4-3. Washington scored two runs in the top of the fifth and Utah again rallied in the bottom of the inning with two runs on three hits to put the score at 6-5. The Huskies again pulled ahead with three runs in the sixth following a three-run home run. Utah made it 9-7 with two runs in the seventh inning. Tom walked to lead off the inning and Erick Migueles hit an RBI double. Migueles scored later in the inning on a ground out following an error.Washington added insurance runs in the late innings to pull ahead for the final score of 13-7, scoring a run in the eighth and plating three runs in the ninth.The Utes play their final series of the season on the road at Washington State beginning on Thursday, May 24, at 4:00 p.m. PT, with all three games aired on the Pac-12 Networks.last_img read more

Richfield’s Hayden Harward Places First At Cedar Invitational

first_imgSeptember 29, 2018 /Sports News – Local Richfield’s Hayden Harward Places First At Cedar Invitational Tags: Aspen Workman/Avery Foster/Brianne Beard/Cannon Anderson/Carli Begay/Carson Utley/Cason Southwick/Cody Rivers/Daran Beard/Dustin Bistline/Dylan Bistline/Elena Torgersen/Hannah Steele/Hayden Harward/Jake Church/Jamie Holt/Justin Reidhead/Justus Reitz/Kanab/Keenan Janke/McKenna Alger/Nathan Bowman/Nick Woolsey/Nora Foster/Richfield Cross Country/SeOnna Southwick Brad James Written by FacebookTwitterLinkedInEmailCEDAR CITY, Utah-Friday, various Mid-Utah Radio Sports Network school athletes competed at the Cedar High Cross Country Invitational, with Richfield’s Hayden Harward excelling above all of them.In the boys’ 3-mile run, Harward won the individual title, posting a time of 15:14.50, netting his second overall win of the season for the Wildcats.Harward’s contributions helped the Wildcats place 10th overall, with a collective score of 263. Other Wildcats who placed included Nick Woolsey (42nd place, 16:41.70), Justus Reitz (73rd place, 17:37.50), Cody Rivers (93rd place, 18:14.20), Cannon Anderson (94th place, 18:16.00), Carson Utley (101st place, 18:44.50), Cason Southwick (102nd place, 18:47.50), Keenan Janke (104th place, 19:04.80) and Daran Beard (111th place, 20:09.70).Kanab’s boys also excelled, placing 13th overall and netting a score of 410. For the Cowboys, Nathan Bowman finished 89th overall, posting a time of 18:03.60. Other Cowboys to place included Dustin Bistline (91st place, 18:12.70), Dylan Bistline (95th place, 18:19.00), Jake Church (103rd place, 18:56.40) and Justin Reidhead (110th place, 20:09.40).For the girls, Richfield placed 7th overall in the standings with 228 points. SeOnna Southwick was the highest-placing Wildcat, finishing in 36th place (19:56.90). Also placing for the Wildcats were Jamie Holt (45th place, 20:14.50), Nora Foster (57th place, 20:44.70), Avery Foster (64th place, 21:07.60), Aspen Workman (66th place, 21:10.10), McKenna Alger (84th place, 23:00.10), Carli Begay (85th place, 23:09.20), Hannah Steele (86th place, 23:09.60), Elena Torgersen (95th place, 24:38.30) and Brianne Beard (97th place, 24:53.40).last_img read more

Bees Edge River Cats

first_imgBour’s homer highlighted a seven-run second inning for Salt Lake.  Tags: PCL/Salt Lake Bees May 23, 2019 /Sports News – Local Bees Edge River Cats Robert Lovell FacebookTwitterLinkedInEmail (Sacramento, CA)  —  Justin Bour clubbed a grand slam and finished with five RBI as the Bees edged the River Cats 9-8 in Sacramento.  Written by The Bees improved to 20-and-25 and continue their series in Sacramento tonight. last_img

Utah Football’s Tyler Huntley, Francis Bernard, Named Pac-12 Players of the Week

first_img Written by FacebookTwitterLinkedInEmailSAN FRANCISCO-Monday, the Pac-12 named University of Utah senior quarterback Tyler Huntley and senior linebacker Francis Bernard their offensive and defensive players of the week, respectively as the No. 17 Utes clobbered Washington State 38-13.Huntley went 21-30 for 334 yards and two touchdowns in the Utes’ Homecoming rout of the Cougars. Huntley also ran for 31 yards and a pair of scores in the win.This is Huntley’s second Pac-12 offensive player of the week award as he was honored by the conference October 20, 2018 when the Utes downed the Trojans 41-28.Huntley was also named as the Rose Bowl Pac-12 player of the week and one of the Davey O’Brien “Great 8” performers of the week.Huntley ranks 7th nationally and second in the Pac-12 by completing 74.6 percent of his passes. He is 12th in the nation, and second in the Pac-12 in passing efficiency (179.3).Bernard posted 12 tackles and his second interception of the year in the win against Washington State.This is Bernard’s second-career Pac-12 defensive player of the week award as he was also honored August 29, 2019 when the Utes downed hated rival BYU 30-12.Bernard is second on the squad with 37 tackles and is third nationally in interception return yardage with 80 interception return yards. Brad James Tags: Francis Bernard/Pac-12 Player of the week award/Tyler Huntley/Utah Football October 1, 2019 /Sports News – Local Utah Football’s Tyler Huntley, Francis Bernard, Named Pac-12 Players of the Weeklast_img read more