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  • 201. Anton, K.
    Plant distribution along a snow-cover gradient with special reference to microclimatic conditions of selected macrolichens near Vassijaure, Swedish Lapland.1993Studentuppsats (Examensarbete)
  • 202. Anton, K.
    et al.
    Bodin, A.
    Eckstein, R.L.
    Measurements of pH variations in front of glaciers in the Abisko region.1993Ingår i: STOU-NG, Vol. 96, s. 34-36Artikel i tidskrift (Övrigt vetenskapligt)
  • 203. Anton, K.
    et al.
    Eckstein, R.L.
    Accumulation of nitrogen and carbon on moraines of different age in front of the Kårsaglacier, Swedish Lapland.1991Rapport (Övrigt vetenskapligt)
  • 204. Antonsson, Henrik
    et al.
    Björk, Robert G.
    Molau, Ulf
    Nurse plant effect of the cushion plant Silene acaulis (L.) Jacq. in an alpine environment in the subarctic Scandes, Sweden2009Ingår i: Plant Ecology & Diversity, Vol. 2, nr 1, s. 17-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Facilitation plays important roles in the structuring of plant communities and several studies have found that it tends to increase with environmental severity in alpine plant communities. In addition, cushion plants have been shown to act as nurse plants, moderating extreme environmental conditions, and providing resources for other species, with substantial effects on local plant diversity. Aims: This study addresses the nurse plant effects of Silene acaulis – a common, circumpolar alpine plant species with a compact cushion-forming growth form – along an altitude transect in the mid- to high-alpine zones in northern Sweden. Methods: The numbers of species in paired S. acaulis cushions and identical-sized control plots along an altitude transect between 1150 m and 1450 m above sea level were compared, and differences in species composition were analysed. Results: At altitudes above c. 1280 m, but not at lower altitudes, more species were found inside the cushions than in their paired control plots. Species composition was similar inside cushions and in control plots. Conclusions: Our results suggest that S. acaulis acts as a nurse plant at altitudes higher than a certain threshold (c. 1280 m at the investigated site). It appears to play an important role in creating focal points for local vascular plant diversity in high-alpine environments, where vegetation is open and occurs in small patches.

  • 205. Arbetarnas bildningsförbund,
    Vår framtida fritidsmiljö - Torneträskområdet1980Rapport (Övrigt vetenskapligt)
  • 206. Arbetsgruppen för de outbyggda älvarna,
    Promemoria den 20 november 1969. Del 1: Redogörelse, överväganden och förslag.1969Rapport (Övrigt vetenskapligt)
  • 207. Arcalis-Planas, Anna
    et al.
    Sveegaard, Signe
    Karlsson, Olle
    Hårding, Karin C.
    Wåhlin, Anna
    Harkonen, Tero
    Teilmann, Jonas
    Limited use of sea ice by the Ross seal (Ommatophoca rossii), in Amundsen Sea, Antarctica, using telemetry and remote sensing data2015Ingår i: Polar Biology, ISSN 0722-4060, E-ISSN 1432-2056, Vol. 38, nr 4, s. 445-461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To understand the use and importance of the Antarctic sea ice to the Ross seal (Ommatophoca rossii), four adult females were tagged with Argos satellite transmitters in the Amundsen Sea, Antarctica. The Ross seal is the least studied of the Antarctic seal species and nothing was previously known about their behaviour in the Amundsen Sea. During almost 1 year, their movements, haul out behaviour and time spent at different temperatures were logged. By comparing their movements with daily ice maps, distances to the ice edge were calculated, and seals dependence on sea ice for resting, breeding and moulting was analysed. The tagged seals spent on average 70.8 % (range 66.8-77.8 %) of their time in the water and hauled out mainly during the moult in December-January, and in late October-mid-November during breeding. During the pelagic period, they were on average 837.5 km (range 587-1,282 km) from the ice edge indicating a fully pelagic life during several months. Their pelagic behaviour suggests that Ross seals, although being an ice obligate species, may adapt comparatively easy to climate change involving ice melting and recession and thereby potentially being less sensitive to the reduction of sea ice than other Antarctic seal species. Although nothing is known about their mating behaviour, they appear to be relatively stationary during moulting and breeding, hence requiring a small ice surface. Although previous studies in other parts of Antarctica have found similar results, still many questions remain about this peculiar species.

  • 208. Arck, M.
    et al.
    Scherer, D.
    Problems in the determination of sensible heat flux over snow.2002Ingår i: Geografiska Annaler, Vol. 84A, nr 3-4, s. 157-170Artikel i tidskrift (Övrigt vetenskapligt)
  • 209. Arft, A.M.
    et al.
    Walker, M.D.
    Gurevitch, J.
    Alatalo, J.M.
    Bret-Harte, M.S.
    Dale, M.
    Diemer, M.
    Gugerli, F.
    Henry, G.H.R.
    Jones, M.H.
    Hollister, R.D.
    Responses of tundra plants to experimental warming: meta-analysis of the International Tundra Experiment.1999Ingår i: Ecological Monographs, Vol. 69, nr 4, s. 491-511Artikel i tidskrift (Övrigt vetenskapligt)
  • 210. ARGALADEI-expeditionen,
    Lullehacårro-grottan, en liten vägvisare.1980Rapport (Övrigt vetenskapligt)
  • 211. Armstrong, E.A.
    The behaviour of birds in continuous daylight.1954Ingår i: Ibis, Vol. 96, s. 1-30Artikel i tidskrift (Övrigt vetenskapligt)
  • 212. Armstrong, E.A.
    The song-flights of some northern birds.1953Ingår i: Ibis, Vol. 95, s. 143-145Artikel i tidskrift (Övrigt vetenskapligt)
  • 213. Arnault, Joel
    et al.
    Kirkwood, Sheila
    Dynamical influence of gravity waves generated by the Vestfjella Mountains in Antarctica: radar observations, fine scale modelling and kinetic energy budget analysis2012Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 64, s. 1-21Artikel i tidskrift (Refereegranskat)
  • 214. Arnborg, T.
    Phytogeographical Forest Excursion to North Sweden, July 2l - August 6, 1950.1950Rapport (Övrigt vetenskapligt)
  • 215.
    Arndt, Jan Erik
    et al.
    Alfred Wegener Inst Polar & Marine Res, Bremerhaven, Germany..
    Schenke, Hans Werner
    Alfred Wegener Inst Polar & Marine Res, Bremerhaven, Germany..
    Jakobsson, Martin
    Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden..
    Nitsche, Frank O.
    Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY USA..
    Buys, Gwen
    British Antarctic Survey, Cambridge CB3 0ET, England..
    Goleby, Bruce
    Geosci Australia, Canberra, ACT, Australia..
    Rebesco, Michele
    Ist Nazl Oceanog & Geofis Sperimentale, Sgonico, Italy..
    Bohoyo, Fernando
    Inst Geol & Minero Espana, Madrid, Spain..
    Hong, Jongkuk
    Korean Polar Res Inst, Inchon, South Korea..
    Black, Jenny
    Inst Geol & Nucl Sci, Lower Hutt, New Zealand..
    Greku, Rudolf
    Ukrainian Acad Sci, Inst Geol Sci, Kiev, Ukraine..
    Udintsev, Gleb
    Vemadsky Inst Geochem & Analyt Chem, Moscow, Russia..
    Barrios, Felipe
    Serv Hidrog & Oceanog, Valparaiso, Chile..
    Reynoso-Peralta, Walter
    Serv Hidrog Naval, Buenos Aires, DF, Argentina..
    Taisei, Morishita
    Japan Coast Guard, Hydrog & Oceanog Dept, Tokyo, Japan..
    Wigley, Rochelle
    Univ New Hampshire, Ctr Coastal & Ocean Mapping, Joint Hydrog Ctr, Durham, NH 03824 USA..
    The International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0-A new bathymetric compilation covering circum-Antarctic waters2013Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 40, nr 12, s. 3111-3117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0 is a new digital bathymetric model (DBM) portraying the seafloor of the circum-Antarctic waters south of 60 degrees S. IBCSO is a regional mapping project of the General Bathymetric Chart of the Oceans (GEBCO). The IBCSO Version 1.0 DBM has been compiled from all available bathymetric data collectively gathered by more than 30 institutions from 15 countries. These data include multibeam and single-beam echo soundings, digitized depths from nautical charts, regional bathymetric gridded compilations, and predicted bathymetry. Specific gridding techniques were applied to compile the DBM from the bathymetric data of different origin, spatial distribution, resolution, and quality. The IBCSO Version 1.0 DBM has a resolution of 500 x 500 m, based on a polar stereographic projection, and is publicly available together with a digital chart for printing from the project website (www.ibcso.org) and at .

  • 216. Arneborg, L.
    et al.
    Wåhlin, A. K.
    Björk, G.
    Liljebladh, B.
    Orsi, A. H.
    Persistent inflow of warm water onto the central Amundsen shelf2012Ingår i: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 5, nr 12, s. 876-880Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The West Antarctic Ice Sheet contains enough ice to raise global sea level by several metres and, because it is grounded mainly below sea level, it is sensitive to ocean warming 1 . Accelerated thinning of glaciers that discharge into the Amundsen Sea over the past decades 2–4 has been proposed to be related to the presence of warmer waters beneath the ice shelves 4–6 . Three deep troughs crosscut the continental shelf of the Amundsen Sea, forming passages through which warm ocean waters can access the ice shelves, but oceanographic data has been limited. Here we present direct measurements from an ocean mooring and ship transect of the temperatures, salinities and velocities from one of these troughs in the central Amundsen Sea during the year 2010. The data show persistent inflow towards the ice shelf of relatively warm and salty water at the bottom of the trough throughout the year, and outflow of colder water above. Superposed on this background flow are barotropic current fluctuations that do not contribute significantly to the overall transport. In contrast to numerical models 7,8 , which show seasonal inflow changes in response to regional winds, we find that warm water is supplied to the Central Amundsen Shelf without strong seasonal variability.

  • 217. Arnell, H.W.
    Die schwedischen Arten der Gattungen Diplohyllum und Martinellia.1922Rapport (Övrigt vetenskapligt)
  • 218. Arnell, H.W.
    Die schwedischen Jungermania-Arten.1925Ingår i: Arkiv för Botanik, Vol. 19, nr 10, s. 1-99Artikel i tidskrift (Övrigt vetenskapligt)
  • 219. Arnell, S.
    Bidrag till kännedomen om levermossfloran i Norrbotten och Torne Lappmark.1941Ingår i: Botaniska Notiser, Vol. 1941, s. 226-230Artikel i tidskrift (Övrigt vetenskapligt)
  • 220. Arnell, S.
    Comments on some Swedish species of Cephaloziella.1950Ingår i: Botaniska Notiser, Vol. 1950, nr 1, s. 83-90Artikel i tidskrift (Övrigt vetenskapligt)
  • 221. Arnell, S.
    Leiocolea arctica nov. spec.1950Ingår i: Svensk Botanisk Tidskrift, Vol. 44, nr 2, s. 374-378Artikel i tidskrift (Övrigt vetenskapligt)
  • 222. Arnell, S.
    New hepatics found in Sweden and Norway.1954Ingår i: Svensk Botanisk Tidskrift, Vol. 48, nr 4, s. 796-797Artikel i tidskrift (Övrigt vetenskapligt)
  • 223. Arnell, S.
    Tre nya storcelliga levermossvarieteter.1950Ingår i: Svensk Botanisk Tidskrift, Vol. 44, nr 1, s. 81-85Artikel i tidskrift (Övrigt vetenskapligt)
  • 224. Arnemo, R.
    et al.
    Rosén, G.
    Fågel- och däggdjursiakttagelser i Abisko1956Ingår i: Fauna och flora, Vol. 51, nr 5-6, s. 219-222Artikel i tidskrift (Övrigt vetenskapligt)
  • 225. Aronson, Richard B
    et al.
    Smith, Kathryn E
    Vos, Stephanie C
    McClintock, James B
    Amsler, Margaret O
    Moksnes, Per-Olav
    Ellis, Daniel S
    Kaeli, Jeffrey
    Singh, Hanumant
    Bailey, John W
    Schiferl, Jessica C
    van Woesik, Robert
    Martin, Michael A
    Steffel, Brittan V
    Deal, Michelle E
    Lazarus, Steven M
    Havenhand, Jonathan N
    Swalethorp, Rasmus
    Kjellerup, Sanne
    Thatje, Sven
    No barrier to emergence of bathyal king crabs on the Antarctic shelf.2015Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithodidae), which were discovered recently on the adjacent continental slope. During the austral summer of 2010‒2011, we used underwater imagery to survey a slope-dwelling population of the lithodid Paralomis birsteini off Marguerite Bay, western Antarctic Peninsula for environmental or trophic impediments to shoreward expansion. The population density averaged ∼4.5 individuals × 1,000 m(-2) within a depth range of 1,100‒1,500 m (overall observed depth range 841-2,266 m). Images of juveniles, discarded molts, and precopulatory behavior, as well as gravid females in a trapping study, suggested a reproductively viable population on the slope. At the time of the survey, there was no thermal barrier to prevent the lithodids from expanding upward and emerging on the outer shelf (400- to 550-m depth); however, near-surface temperatures remained too cold for them to survive in inner-shelf and coastal environments (<200 m). Ambient salinity, composition of the substrate, and the depth distribution of potential predators likewise indicated no barriers to expansion of lithodids onto the outer shelf. Primary food resources for lithodids-echinoderms and mollusks-were abundant on the upper slope (550-800 m) and outer shelf. As sea temperatures continue to rise, lithodids will likely play an increasingly important role in the trophic structure of subtidal communities closer to shore.

  • 226. Aronsson, M.
    Floraväkteri i Torne Lappmark 1997.1998Ingår i: Svensk Botanisk Tidskrift, Vol. 92, nr 1, s. 21-Artikel i tidskrift (Övrigt vetenskapligt)
  • 227. Aronsson, M.
    Inte bara lappfela - fem års botanikkurs i Abisko.2000Ingår i: Svensk Botanisk Tidskrift, Vol. 94, nr 2, s. 123-134Artikel i tidskrift (Övrigt vetenskapligt)
  • 228. Aronsson, M.
    Sammanställning av Torneträskområdets växter.1991Manuskript (preprint) (Övrigt vetenskapligt)
  • 229. Aronsson, M.
    Torneträskområdets kärlväxter.1994Manuskript (preprint) (Övrigt vetenskapligt)
  • 230. Aronsson, M.
    Torneträskområdets kärlväxter.1998Rapport (Övrigt vetenskapligt)
  • 231. Aronsson, M.
    Torneträskområdets kärlväxter.2002Rapport (Övrigt vetenskapligt)
  • 232. Aronsson, M.
    Torneträskområdets kärlväxter.1999Rapport (Övrigt vetenskapligt)
  • 233. Aronsson, M.
    Torneträskområdets kärlväxter checklista.1996Rapport (Övrigt vetenskapligt)
  • 234. Aronsson, M
    et al.
    Lund, S
    Nya fynd av oppdalsbräcka Saxifraga x opdalensis2013Ingår i: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 108, nr 4, s. 18-20Artikel i tidskrift (Refereegranskat)
  • 235. Arrhenius, O.
    Ståndort och osmotiskt tryck.1919Rapport (Övrigt vetenskapligt)
  • 236. Arrhenius, O.
    et al.
    Söderberg, E.
    Der osmotische Druck der Hochgebirgspflanzen.1918Ingår i: Svensk Botanisk Tidskrift, Vol. 11, nr 3-4, s. 373-380Artikel i tidskrift (Övrigt vetenskapligt)
  • 237. Arwidsson, Th.
    Mykologische Beiträge.1936Ingår i: Botaniska Notiser, Vol. 1936, s. 463-480Artikel i tidskrift (Övrigt vetenskapligt)
  • 238. Arwidsson, Th.
    Über einige auf der Gattung Empetrum vorkommende Pilze.1936Ingår i: Svensk Botanisk Tidskrift, Vol. 30, nr 3, s. 401-418Artikel i tidskrift (Övrigt vetenskapligt)
  • 239. Ask, Jenny
    et al.
    Karlsson, Jan
    Persson, Lennart
    Ask, Per
    Byström, Pär
    Jansson, Mats
    Whole-lake estimates of carbon flux through algae and bacteria in benthic and pelagic habitats of clear-water lakes2009Ingår i: Ecology, Vol. 90, nr 7, s. 1923-1932Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study quantified new biomass production of algae and bacteria in both benthic and pelagic habitats of clear-water lakes to contrast how carbon from the atmosphere and terrestrial sources regulates whole-lake metabolism. We studied four small unproductive lakes in subarctic northern Sweden during one summer season. The production of new biomass in both benthic and pelagic habitats was calculated as the sum of autotrophic production by algae and heterotrophic production by bacteria using allochthonous organic carbon (OC). Whole-lake production of new biomass was dominated by the benthic habitat  (86% ± 4% [mean ± SD]) and by primary production (77% ± 9% Still, heterotrophic bacteria fueled by allochthonous OC constituted a significant portion of the new biomass production in both benthic  (19% ± 11%) and pelagic habitats (51% ± 24%).In addition, overall net production (primary production minus respiration) was close to zero in the benthic habitats but highly negative (−163 ± 81 mg C·m−2·d−1)) in pelagic regions of all lakes. We conclude (1) that allochthonous OC supported a significant part of total production of new biomass in both pelagic and benthic habitats, (2) that benthic habitats dominated the whole-lake production of new biomass, and (3) that respiration and net CO2 production dominated the carbon flux of the pelagic habitats and biomass production dominated the benthic carbon flux. Taken together, these findings suggest that previous investigations have greatly underestimated the productivity of clear-water lakes when benthic autotrophic production and metabolism of allochthonous OC have not been measured.

  • 240. Asklund, B.
    En återblick på den svenska fjällkedjeforskningen.1946Ingår i: GFF, Vol. 68, nr 2, s. 212-250Artikel i tidskrift (Övrigt vetenskapligt)
  • 241. Asplund, C.I.
    Till Rautasvuoma lappar och Jukkasjärvi högfjäll.1905Rapport (Övrigt vetenskapligt)
  • 242. Asplund, E.
    Taxonomical Excursion to the Subalpine and Alpine Belts of Northern Lappland, July 2l - August 3, 1950.1950Konferensbidrag (Övrigt vetenskapligt)
  • 243.
    Aune, K.
    Naturgeografi.
    GIS som metod för planering av turism i fjällmiljö: en metodstudie i Torneträskområdet.1998Studentuppsats (Examensarbete)
  • 244. Aurén, T.E.
    Observations concerning ultra-violet solar radiation in some places in Sweden.1930Ingår i: Geografiska Annaler, Vol. 3, nr 3-4, s. 257-267Artikel i tidskrift (Övrigt vetenskapligt)
  • 245. Aurén, T.E.
    Radiation Climate in Scandinavian Peninsula.1939Rapport (Övrigt vetenskapligt)
  • 246. Avery, G.S. Jr.
    Lappland - Magnificent and Strangely Interesting.1951Ingår i: Brooklyn Botanic Garden Record. Plants & Gardens. New Series 7(2): 76-83, Vol. 7, nr 2, s. 76-83Artikel i tidskrift (Övrigt vetenskapligt)
  • 247. Awebro, K.
    Tre gruvfält i norr - Gustafsfält, Kalix kopparbruk och Sjangeli1989Ingår i: Studia Lapplandia, Vol. 10, s. 49-72Artikel i tidskrift (Övrigt vetenskapligt)
  • 248. Axelsson, M
    et al.
    Agnisola, C
    Nilsson, S
    Tota, B
    Fish cardio-circulatory function in the cold1998Ingår i: SEMINAR SERIES-SOCIETY FOR EXPERIMENTAL BIOLOGY, 1998, Vol. 66, s. 327-364Konferensbidrag (Refereegranskat)
  • 249. AXELSSON, M
    et al.
    DAVISON, B
    FORSTER, M
    NILSSON, S
    BLOOD-PRESSURE CONTROL IN THE ANTARCTIC FISH PAGOTHENIA-BORCHGREVINKI1994Ingår i: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 190, s. 265-279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanisms of cardiovascular control in the Antarctic fish Pagothenia borchgrevinki were investigated during rest and swimming exercise using pharmacological tools to reveal the nature of the control systems involved. Simultaneous and continuous recordings of ventral and dorsal aortic blood pressure, heart rate and ventral aortic blood flow (cardiac output) were made using standard cannulation procedures and a single-crystal Doppler flowmeter. Exercise produced a clear and consistent decrease in dorsal aortic blood pressure caused by a decrease in systemic vascular resistance. At the same time, ventral aortic blood pressure increased owing to the combined effects of a markedly increased cardiac output (by about 80 %) and branchial vasoconstriction. Judged from the effects of the alpha-adrenoceptor antagonist prazosin, control of the branchial vasculature involves an alpha-adrenoceptor-mediated vasoconstriction, in addition to more traditional cholinergic vasoconstrictor and beta-adrenoceptor-mediated dilatory mechanisms. The range of heart rates is large, from 3-4 beats min(-1) in individual fish during hypertensive bradycardia to about 28 beats min(-1) after atropine treatment. Both chronotropic and inotropic effects are responsible for a marked increase in cardiac output during exercise. The increase in blood pressure caused by adrenaline injection was due largely to an increase in cardiac output, while direct effects on the systemic vasculature were small and transient. The increase in cardiac output, in turn, was due solely to an adrenergic stimulation of stroke volume. A barostatic bradycardia, often seen in other vertebrates in response to adrenaline injection, was absent and it is possible that a decrease in heart rate was offset by direct adrenergic stimulation of the heart. Angiotensin II (Ang II) produced consistent hypertension by systemic vasoconstriction. In contrast to the effects of adrenaline injection, the hypertension caused by Ang II was accompanied by a marked bradycardia. This could be abolished by atropine, suggesting a cholinergic vagal reflex of the type found in other vertebrates.

  • 250. AXELSSON, M
    et al.
    DAVISON, W
    FORSTER, ME
    FARRELL, AP
    CARDIOVASCULAR-RESPONSES OF THE RED-BLOODED ANTARCTIC FISHES PAGOTHENIA-BERNACCHII AND P-BORCHGREVINKI1992Ingår i: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 167, s. 179-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to investigate cardiac performance and cardiovascular control in two red-blooded nototheniid species of antarctic fishes, Pagothenia bernacchii (a benthic fish) and P. borchgrevinki (a cryopelagic fish), and to make comparisons with existing information on haemoglobin-free antarctic teleosts. In quiescent P. bernacchii at 0-degrees-C ventral aortic pressure (PVA) was 3.09 kPa and cardiac output (Q) was 17.6 ml min-1 kg-1, with a heart rate (fH) of 10.5 beats min-1 and stroke volume of 1.56 ml kg-1. Following atropine treatment, Q was maintained but heart rate increased and stroke volume decreased. Resting heart rate resulted from an inhibitory cholinergic tone of 80.4 % and an excitatory adrenergic tone of 27.5 %. The intrinsic heart rate was 21.7 beats min-1 at 0-degrees-C. In quiescent P. borchgrevinki at 0-degrees-C, PVA was 3.6 kPa, Q was 29.6 ml min-1 kg-1 and stroke volume was 2.16 ml kg-1. The resting heart rate in P. borchgrevinki of 11.3 beats min-1 resulted from an inhibitory cholinergic tone of 54.5 % and an excitatory adrenergic tone of 3.2 %. The intrinsic heart rate was 23.3 beats min-1. P. bernacchii maintained Q during a progressive decrease in water oxygen tension from 20 to 6.7 kPa, but fH was increased significantly. Thus, although there is cholinergic control of the heart, no hypoxic bradycardia was observed. Recovery from hypoxia was associated with increases in Q and fH; stroke volume returned to control values. PvA declined in recovery as total vascular resistance decreased. Hypoxic exposure following atropine treatment resulted in progressive increases in PVA, Q and stroke volume; fH decreased during the recovery period. Hypoxic exposure in P. borchgrevinki produced similar cardiovascular responses to those observed in P. bernacchii. During an acute increase in water temperature from 0 to 5-degrees-C, P. bernacchii regulated Q and total vascular resistance. Stroke volume decreased as fH increased. The intrinsic heart rate had a Q10 of 1.96 over this temperature range. P. bernacchii maintained chronotropic inhibition up to a temperature of 2.5-3.0-degrees-C. However, by 5-degrees-C this chronotropic inhibition of the heart rate was lost. Infusion of adrenaline into the ventral aorta of P. bernacchii resulted in significant increases in Q, fH, PVA and total vascular resistance. Infusion of adrenaline after atropine treatment caused similar cardiovascular changes without the change in fH. P. borchgrevinki could sustain swimming in a water tunnel at approximately 1 body length per second for 6-10 min. During the bout of swimming there was a doubling of ventilation frequency, a 75 % increase in Q as fH doubled and a decrease in total vascular resistance. Similarities exist between these two red-blooded antarctic teleosts and haemoglobin-free channichthyids. These include a low PvA, associated with a low vascular resistance, and a high cardiac stroke volume. Ventricle mass is somewhat larger than in temperate species of teleosts, especially considering the low aortic pressures developed by the heart. The absence of a sustained bradycardia in P. bernacchii during hypoxia or an adrenaline-induced increase in PVA is unusual. This may in part reflect the very high inhibitory cholinergic tone to the heart, the highest value found in resting fish.

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