Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory

first_imgAstrammina rara, Crithionina delacai, and Notodendrodes hyalinosphaira are 3 of the largest and most abundant members of the foraminiferal assemblage at a shallow-water (28 to 32 m) site in Explorers Cove, Antarctica. This study summarizes observations from 2 decades of research, during which we employed laboratory-based feeding experiments and fatty acid biomarker analysis to characterize trophic dynamics and ecological roles of the 3 species, In feeding experiments, A. rara consumed a variety of co-occurring metazoans (several Crustacea, Mollusca, Echinodermata, and a Nephtys species). C. delacai, N. hyalinosphaira, and a number of other foraminiferal species from Explorers Cove successfully trapped Artemia sp. nauplius prey in a setup designed to examine the efficiency of prey capture. Fatty acid analyses on samples from early (November 7, 2001) and late (January 31, 2002) austral summer revealed that the 3 species contained substantial amounts (33 to 45.5%) of polyunsaturated fatty acids (PUFAs), which are produced by microalgae, indicating the downwards transfer of carbon from sea-ice associated primary production. In the case of A. rara, this may be due to the ingestion of herbivorous metazoa, rather than direct uptake of microalgal material. A. rara contained significantly (p < 0.05) higher amounts of the zooplankton biomarkers 20:1(n-9) and 22:1(n-11), and C. delacai contained more PUFAs early, compared to late, in the season. Two morphotypes of N. hyalinosphaira had different fatty acid Profiles, indicating distinct trophotypes. Our results illustrate specific adaptations to different trophic resources in these protists, and they demonstrate the potential impact that large carnivorous species of Foraminifera may have on the structure of benthic communities where they are abundant.last_img read more

Influence of Patagonian glaciers on Antarctic dust deposition during the last glacial period

first_imgIce cores provide a record of changes in dust flux to Antarctica, which is thought to reflect changes in atmospheric circulation and environmental conditions in dust source areas(1-9). Isotopic tracers suggest that South America is the dominant source of the dust(10-12), but it is unclear what led to the variable deposition of dust at concentrations 20-50 times higher than present in glacial-aged ice(8,9). Here we characterize the age and composition of Patagonian glacial outwash sediments, to assess the relationship between the Antarctic dust record from Dome C (refs 9, 13) and Patagonian glacial fluctuations(14-16) for the past 80,000 years. We show that dust peaks in Antarctica coincide with periods in Patagonia when rivers of glacial meltwater deposited sediment directly onto easily mobilized outwash plains. No dust peaks were noted when the glaciers instead terminated directly into pro-glacial lakes. We thus propose that the variable sediment supply resulting from Patagonian glacial fluctuations may have acted as an on/off switch for Antarctic dust deposition. At the last glacial termination, Patagonian glaciers quickly retreated into lakes, which may help explain why the deglacial decline in Antarctic dust concentrations preceded the main phase of warming, sea-level rise and reduction in Southern Hemisphere sea-ice extent(13).last_img read more

Lake highstands in the Pensacola Mountains and Shackleton Range 4300-2250 cal. yr BP: Evidence of a warm climate anomaly in the interior of Antarctica

first_imgWe surveyed and dated the former shorelines of one lake in the Shackleton Range and two lakes in the Pensacola Mountains, situated inland of the Weddell Sea embayment Antarctica between 80° and 85°S. These are amongst the highest latitude lakes in the Antarctic and are located in areas where there is little or no Holocene climate and hydrological information. Surveys of the lake shorelines show that past water levels have been up to 15.7, 17.7 and 69.5 m higher than present in the three study lakes. AMS radiocarbon dating of lake-derived macrofossils showed that there was a sustained period of higher water levels from approximately 4300 and until sometime after 2250 cal. yr BP. This is interpreted as being the result of an increased number of meltwater events and/or degree-days above freezing, relative to the present. The closest comparable ice cores from the Dominion Range in the Transantarctic Mountains (85°S, 166°E) and the Plateau Remote ice core on the continental East Antarctic Ice Sheet (84°S, 43°E) also provide some evidence of a warmer period beginning at c. 4000–3500 yr BP and ending after 2000–1500 yr BP, as does a synthesis of oxygen isotope data from five Antarctic ice cores. This suggests that the well-documented mid- to late-Holocene warm period, measured in many lake and marine sediments around the coast of Antarctica, extended into these regions of the continental interior.last_img read more

The taxonomy and palaeobiogeography of small chorate dinoflagellate cysts from the Late Cretaceous to Quaternary of Antarctica

first_imgSmall chorate dinoflagellate cysts are common in Upper Cretaceous to Quaternary sedimentary successions around the Antarctic margin. Taxonomic confusion surrounding dinoflagellate cysts and acritarchs of similar morphology throughout the southern high palaeolatitudes has hitherto limited investigation of their palaeoecological significance. This study aims to solve the taxonomic problems, and to allow a new assessment of dinoflagellate cyst acmes. A detailed morphological study of new material from the López de Bertodano Formation of Seymour Island, Antarctic Peninsula, is presented. These dinoflagellate cysts are identified as Impletosphaeridium clavusWrenn & Hart 1988 emend. nov. Their gross morphology and their vast abundances in the James Ross Basin are strongly suggestive of dinoflagellate blooms. This scenario implies similarities to modern dinoflagellate cysts from the polar regions.last_img read more

DVM: The World’s Biggest Game of Hide-and-Seek

first_imgDiel vertical migration (DVM) refers to the daily, synchronized movement of marine animals between the surface and deep layers of the open ocean. This behavior is the largest animal migration on the planet and is undertaken every single day by trillions of animals in every ocean. Like a big game of hide-and-seek, animals that perform DVM spend the day hiding from predators in the deep ocean, and then migrate to the surface to feed under the cover of darkness. In this article we will explore this incredible strategy for survival. We will introduce the animals involved, describe how the environment of the open ocean drives DVM, and reveal the questions still to be answered as the ocean environment continues to change.last_img read more

Utah Baseball Drops Season Opener at Texas State

first_img FacebookTwitterLinkedInEmailSAN MARCOS – Utah dropped its season opener to Texas State 8-3 in San Marcos, Texas on Friday, February 15.Erick Migueles led the way at the plate going 2-4 and having an RBI. Dominic Foscalina also had an RBI for the Utes.Utah got to the Bobcats early scoring two runs in the second to tie the score and then took the lead in the third scoring one more run. Oliver Dunn doubled in the beginning of the inning and Migueles singled up the middle to bring him home.After taking the lead 3-2, Utah had trouble getting anything going after that. Texas State didn’t give up a hit after the third inning and took the lead back in the fifth for good. They added some insurance runs in the seventh and eighth innings.Kyle Robeniol got the start for Utah and went 4.1 innings. He gave up three earned runs on seven hits. Ian MacIver, David Watson and Zac McCleve made appearances out of the bullpen.For the game, Utah totaled three runs on four hits.The Utes are in a tournament at Texas State and will play Missouri State next at 11 a.m. MT on Saturday, February 16. Riley Pierce will be on the mound for Utah. February 15, 2019 /Sports News – Local Utah Baseball Drops Season Opener at Texas State Robert Lovell Tags: Utah Utes Baseball Written bylast_img read more

USU releases statement regarding postgame incident with Nevada

first_img FacebookTwitterLinkedInEmailLOGAN, Utah – Utah State Vice President and Director of Athletics John Hartwell released the following statement Monday afternoon regarding the postgame incident with its men’s basketball home game against Nevada last weekend. Robert Lovell March 4, 2019 /Sports News – Local USU releases statement regarding postgame incident with Nevada Written bycenter_img “First of all, we want to thank both the Mountain West and the University of Nevada in helping us review the postgame incident from Saturday night. While unfortunate, it should not overshadow what was a great college basketball game between two NCAA Tournament-caliber teams. After reviewing all the evidence, from surveillance video to eyewitness accounts, the incident was not a game management issue and was not caused by our students rushing the court. The unsportsmanlike behavior following the game did not include any of our student-athletes, but rather a couple of staff members, which is unacceptable, and we will handle those issues internally. Moving forward, Utah State Athletics will review our game management procedures in an effort to continually learn and improve.” Tags: Mountain West/Nevada Wolf Pack/Utah State Aggies Basketballlast_img read more

Scoreboard roundup — 8/18/19

first_img Written by FacebookTwitterLinkedInEmailiStock(NEW YORK) — Here are the scores from Sunday’s sports events: MAJOR LEAGUE BASEBALLINTERLEAGUENY Mets 11, Kansas City 5AMERICAN LEAGUESeattle 7, Toronto 0Tampa Bay 5, Detroit 4Boston 13, Baltimore 7Cleveland 8, NY Yankees 4Minnesota 6, Texas 3Houston 4, Oakland 1LA Angels 9, Chi White Sox 2NATIONAL LEAGUESt. Louis 5, Cincinnati 4San Diego 3, Philadelphia 2Atlanta 5, LA Dodgers 3Washington 16, Milwaukee 8Colorado 7, Miami 6, 10 inningsArizona 6, San Francisco 1Chi Cubs 7, Pittsburgh 1WOMEN’S NATIONAL BASKETBALL ASSOCIATIONConnecticut 78, Dallas 68Washington 107, Indiana 68Las Vegas 100, Chicago 85Phoenix 78, New York 72Seattle 82, Minnesota 74NATIONAL FOOTBALL LEAGUE PRESEASONNew Orleans 19, LA Chargers 17Minnesota 25, Seattle 19Copyright © 2019, ABC Radio. All rights reserved. Beau Lundcenter_img August 19, 2019 /Sports News – National Scoreboard roundup — 8/18/19last_img read more

Serena Williams wins 100th US Open match

first_imgSeptember 4, 2019 /Sports News – National Serena Williams wins 100th US Open match Written by FacebookTwitterLinkedInEmailJoe Faraoni / ESPN Images(NEW YORK) — Serena Williams cruised to a speedy victory Tuesday night in the women’s quarterfinals to notch her 100th U.S. Open match win. Williams opened the Arthur Ashe Stadium program, defeating Qiang Wang 6-1, 6-0 in just 44 minutes in front of a packed house.The eighth-ranked Williams earned the historic win 30 years to the day Hall of Famer Chris Evert won her tournament record 101st match. Now, the tennis legend has just two matches left between her and a seventh U.S. Open singles championship title.Williams is also the last American — woman or man — standing in Flushing Meadows in hopes of taking home the fourth and final Grand Slam title of the season. The 23-time Grand Slam champ will face fifth seed Elina Svitolina, who previously upset Williams at the 2016 Rio Olympics.Williams’ last U.S. Open title came in 2014, but she has made it to at least the semifinal round at every U.S. Open she has played since 2007. The electric atmosphere continued for the men’s match, where unseeded Bulgarian Grigor Dimitrov battled and defeated Roger Federer in five sets to close out the evening.Copyright © 2019, ABC Radio. All rights reserved.center_img Beau Lundlast_img read more

Snow Women’s Basketball Closes Out Regular Season With A Win

first_imgFebruary 24, 2020 /Sports News – Local Snow Women’s Basketball Closes Out Regular Season With A Win Brad James Written by Tags: Snow Women’s Basketball FacebookTwitterLinkedInEmailRANGELY, Colo.-Lexi Peterson scored a season-high 19 points on Saturday afternoon, leading the Snow College women’s basketball team to a 71-50 victory over Colorado Northwestern in the Lady Badgers’ regular-season finale.In the third quarter, the Lady Spartans outscored Snow, 21-12 to cut the Lady Badgers’ lead to just five points; however, Snow turned up the heat in the final quarter to outscore CNCC, 25-9 to take the 21-point victory. Shawnee Simpson led the fourth-quarter surge, scoring nine of her 11 points. Snow shot 10-of-14 from the field in the final frame, including 5-of-6 from three-point range. The Snow College defense held the Lady Spartans to just 16.7 percent shooting in the fourth quarter.Regan Yamauchi scored 17 points and had seven rebounds in the victory, while Sydney Pilling added 10 points.The two teams will meet again on Thursday afternoon at the Region XVIII Tournament in Twin Falls, Idaho. Snow, the No. 4 seed, will take on Colorado Northwestern, the No. 5 seed at 5:30 p.m. The winner will take on No. 1 seed Salt Lake C.C. on Friday at 12 noon.last_img read more