Can high Arctic soil microarthropods survive eleveated summer temperatures?

first_img1. Tolerance of high summer temperatures was investigated in seven common species of oribatid mite (Acarina) and springtail (Collembola) found in soils associated with dominant vegetation types in West Spitsbergen, Svalbard. 2. Laboratory survival experiments are linked with field data from a 3-year temperature manipulation experiment to characterize the response of these animals to elevated field temperatures. 3. A 1-h exposure to 30⚬C under moist conditions showed that none of the species studied suffered significant mortality. The temperature required to kill all individuals was between 35-40 and 40-45⚬C for springtails and mites respectively. Under dry conditions at equivalent temperatures, differences in survival between mites and Collembola were strongly accentuated. Oribatid mites were little affected by the additional drought stress but the lethal temperature for springtails was shifted downwards by several degrees. 4. In parallel 3-h exposure experiments under moist conditions, the thermal death point was shifted downwards by c. 2.5⚬C in all the species, compared with 1-h exposures. Under dry conditions most Collembola died but mite survival differed little from that in the corresponding wet treatment over 3 h. 5. In longer-term experiments some mature Onychiurus arcticus survived more than 196 and 68 days at 5 and 25⚬C respectively. Above 30⚬C individuals survived for <24 h. 6. Regression relationships were established between maximum microhabitat temperatures and screen temperatures over 3 years. These were used to predict past maximum vegetation/litter mat and soil temperatures from historical screen data and to estimate the screen temperatures necessary to raise microhabitat temperatures to the thermal death point of the soil-dwelling arthropods. 7. The results are used to interpret the findings of a 3-year field experiment which examined the response of mite and springtail populations to temperature enhancement on two tundra sites, using small polythene tents. 8. High Arctic soil microarthropods appear able to cope with the higher summer temperatures they may experience as a result of climate change. It is the associated changes in soil moisture status that will probably produce the more significant changes in the microarthropod community. Species differ in their susceptibilities, but a decrease in soil moisture appears to favour oribatid mites at the expense of Collembola.last_img read more

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Ejuke: No regrets over Heerenveen move

first_imgRelatedPosts Joe Aribo out of Super Eagles friendlies Immobile extends Lazio contract till 2025 Celtic given tricky tie in UEFA Champions League qualifiers, Red Star drawn away Chidera Ejuke is happy with his decision to sign for Heerenveen last summer and is not thinking about leaving the club despite several interested clubs.Heerenveen picked up the winger last summer from Valerenga, despite interest from Celtic, Lazio and Besiktas. Ejuke said he does not regret his choice: “After talking to the trainer and the technical manager I knew enough.“I can become a better footballer at this club.“And I have not regretted my choice for a moment.“The people on the street are friendly, while everyone at the club wants to help me and give me confidence.”A Chinese club have already had a €7 million offer rejected by the Frisian’s this summer, and plenty of other clubs are showing interest in the Nigerian after an impressive first season in the Eredivisie. However, Ejuke is not thinking of a transfer: “I am not at all busy with a transfer.“Do you know what it is?“I see my career as a great adventure, of which I am only at the beginning.“Above all, I want to be happy and stay healthy.“Especially now we all realise that this is the most important thing.” Tags: BesiktasCelticChidera EjukeHeerenveenLazioValerengalast_img read more

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Andre Ethier’s steady season for LA Dodgers fueled by health, consistency

first_imgAndre Ethier hit an opposite-field single against Colorado Rockies pitcher Jon Gray in his first at-bat Monday — nothing spectacular, but perfectly in line with what he’s paid to do.On most nights this has been the story of Ethier’s 2015 season, which is in itself something remarkable.A player so often reviled for failing to live down his $85 million contract extension, so often the subject of trade rumors, has revived his career with his silent steadiness. The advanced statistics WRC+ and OPS+ both rate Ethier as the Dodgers’ best hitter this year among players with at least 50 plate appearances through Sunday.Ethier said it’s not just he’s been healthy all season, or that his playing time has steadied, “it’s both.” “Beginning of the year we didn’t know what it was going to be,” he said. “I happened to come into this role. The role I’ve had has been consistent since the second or third week of the season. That’s made it easier. “Then health-wise, being back physically, not only feeling right but capable of performing and executing the things I want to execute.”Ethier’s injuries were generally small but impactful, particularly a blister on the palm of his right hand that forced a series of ill-fated adjustments to his swing. Ethier always guarded his comments when discussing his injuries, which made their impact hard to gauge.Ethier did not guard his comments last December when he said he wanted to play every day, a goal that seemed unrealistic given his performance in 2014 and the Dodgers’ glut of outfielders.Since the 2015 season began, Ethier said, “I’m not having to compensate, not having to adjust, just going out there and really — simple as I can put it, just see and hit the ball. Just do that, not having to tinker and figure something out every day. I can see it and figure out a way to hit it. Showing up every day and not having to tinker with it.” Ethier won’t reach the number of plate appearances necessary to qualify for a batting title this season. Because the Dodgers rely so much on platoons, it’s likely that only three players will (Adrian Gonzalez, Joc Pederson and Jimmy Rollins).Yet he began the week batting .295 with a .367 on-base percentage and .484 slugging percentage. Each of those figures are above average for his career, something few 33-year-olds do anymore.At 32, Ethier batted .249 with a .322 on-base percentage and .370 slugging percentage — all career lows.“I think last year was a transition year,” Dodgers hitting coach Mark McGwire said, “and this year he really just said ‘screw it, I’m going to bust my ass and lay it on the line.’ And look what’s happened.”Peraza’s season in perilInfielder Jose Peraza could possibly be lost for the season, depending on the results of an MRI on his strained left hamstring, manager Don Mattingly said.Without Peraza, the Dodgers would be pressed to replace his speed off the bench. Corey Seager, Chase Utley and/or Carl Crawford’s chances of making the National League Division Series roster could improve.How much will it hurt the Dodgers to lose Peraza’s speed off the bench? “That’s up in the air right now,” Mattingly said. “It’s a luxury. Sometimes you would need it. Sometimes you wouldn’t. We had Dee (Gordon) a couple years ago. I think we used him one time. Maybe we had him another time and didn’t use him at all. That’s one of those things you’ll never know whether you need it or not when you get to that spot.” AlsoMattingly said he doesn’t intend to skip any of Clayton Kershaw or Zack Greinke’s scheduled starts the remainder of the season. … Justin Turner is one of seven finalists for the MLB Players’ Association Marvin Miller Man of The Year award. … Adrian Gonzalez is the Dodgers’ nominee for the Roberto Clemente Award, which Kershaw won in 2012 and Rollins won in 2014. … Rollins pushed back his scheduled batting practice and fielding practice to Tuesday and won’t be cleared to return from his right index finger injury before Wednesday. … Carl Crawford (hamstring) was held out of the lineup as a precaution. … Howie Kendrick (hamstring) took part in a simulated game and sprinted in the outfield afterward. He hit a home run.center_img Newsroom GuidelinesNews TipsContact UsReport an Errorlast_img read more

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