#PAGE_PARAMS# #ADS_HEAD_SCRIPTS# #MICRODATA#

DOC export is exceeded by C fixation in May Creek: A late-successional watershed of the Copper River Basin, Alaska


Autoři: Patrick L. Tomco aff001;  Rommel C. Zulueta aff002;  Leland C. Miller aff003;  Phoebe A. Zito aff004;  Robert W. Campbell aff005;  Jeffrey M. Welker aff003
Působiště autorů: Department of Chemistry, University of Alaska Anchorage, Anchorage, Alaska, United States of America aff001;  National Ecological Observatory Network, Inc., Boulder, Colorado, United States of America aff002;  Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, United States of America aff003;  Department of Chemistry, University of New Orleans, New Orleans, Louisiana, United States of America aff004;  Prince William Sound Science Center, Cordova, Alaska, United States of America aff005;  Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland aff006
Vyšlo v časopise: PLoS ONE 14(11)
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pone.0225271

Souhrn

Understanding the entirety of basin-scale C cycling (DOC fluxes and CO2 exchanges) are central to a holistic perspective of boreal forest biogeochemistry today. Shifts in the timing and magnitude of dissolved organic carbon (DOC) delivery in streams and eventually into oceans can be expected, while simultaneously CO2 emission may exceed CO2 fixation, leading to forests becoming stronger CO2 sources than sinks amplifying rising trace gases in the atmosphere. At May Creek, a representative late-successional boreal forest watershed at the headwaters of the Copper River Basin, Alaska, we quantified the seasonality of DOC flux and landscape-scale CO2 exchange (eddy covariance) over two seasonal cycles. We deployed in situ fDOM and conductivity sensors, performed campaign sampling for water quality (DOC and water isotopes), and used fluorescence spectroscopy to ascertain DOC character. Simultaneously, we quantified net CO2 exchange using a 100 ft eddy covariance tower. Results indicate DOC exports were pulse-driven and mediated by precipitation events. Both frequency and magnitude of pulse-driven DOC events diminished as the seasonal thaw depth deepened, with inputs from terrestrial sources becoming major contributors to the DOC pool with decreasing snowmelt contribution to the hydrograph. A three-component parallel factorial analysis (PARAFAC) model indicated DOC liberated in late-season may be bioavailable (tyrosine-like). Combining Net Ecosystem Exchange (NEE) measurements indicate that the May Creek watershed fixes 142–220 g C m-2 yr-1 and only 0.40–0.57 g C m-2 yr-1 is leached out as DOC. Thus, the May Creek watershed and similar mature spruce forest dominated watersheds in the Copper River Basin are currently large ecosystem C sinks and exceeding C conservative. An understanding of DOC fluxes from Gulf of Alaska watersheds is important for characterizing future climate change-induced seasonal shifts.

Klíčová slova:

Carbon dioxide – Ecosystems – Forests – Rivers – Seasons – Spring – Surface water – Watersheds


Zdroje

1. Tarnocai C, Canadell J, Schuur E, Kuhry P, Mazhitova G, Zimov S. Soil organic carbon pools in the northern circumpolar permafrost region. Global biogeochemical cycles. 2009;23(2).

2. Pan Y, Birdsey RA, Fang J, Houghton R, Kauppi PE, Kurz WA, et al. A large and persistent carbon sink in the world’s forests. Science. 2011;333(6045):988–93. doi: 10.1126/science.1201609 21764754

3. Jarvis P, Morison J, Chaloner W, Cannell M, Roberts J, Jones H, et al. Atmospheric carbon dioxide and forests [and discussion]. Philosophical Transactions of the Royal Society B: Biological Sciences. 1989;324(1223):369–92.

4. Dutta K, Schuur EAG, Neff JC, Zimov SA. Potential carbon release from permafrost soils of Northeastern Siberia. Glob Change Biol. 2006;12(12):2336–51.

5. Zimov SA, Schuur EAG, Chapin FS. Permafrost and the global carbon budget. Science. 2006;312(5780):1612–3. doi: 10.1126/science.1128908 16778046

6. Hugelius G, Strauss J, Zubrzycki S, Harden JW, Schuur E, Ping C-L, et al. Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps. Biogeosciences. 2014;11(23):6573–93.

7. Lepistö A, Kortelainen P, Mattsson T. Increased organic C and N leaching in a northern boreal river basin in Finland. Global Biogeochemical Cycles. 2008;22(3).

8. Finlay J, Neff J, Zimov S, Davydova A, Davydov S. Snowmelt dominance of dissolved organic carbon in high‐latitude watersheds: Implications for characterization and flux of river DOC. Geophys Res Lett. 2006;33(10).

9. Laudon H, Berggren M, Ågren A, Buffam I, Bishop K, Grabs T, et al. Patterns and dynamics of dissolved organic carbon (DOC) in boreal streams: the role of processes, connectivity, and scaling. Ecosystems. 2011;14(6):880–93.

10. Stubbins A, Hood E, Raymond PA, Aiken GR, Sleighter RL, Hernes PJ, et al. Anthropogenic aerosols as a source of ancient dissolved organic matter in glaciers. Nature Geoscience. 2012;5(3):198–201.

11. Neal EG, Hood E, Smikrud K. Contribution of glacier runoff to freshwater discharge into the Gulf of Alaska. Geophys Res Lett. 2010;37.

12. Milly PCD, Dunne KA, Vecchia AV. Global pattern of trends in streamflow and water availability in a changing climate. Nature. 2005;438(7066):347–50. doi: 10.1038/nature04312 16292308

13. Chapin FS, Walker LR, Fastie CL, Sharman LC. Mechanisms of Primary Succession Following Deglaciation at Glacier Bay, Alaska. Ecological Monographs. 1994;64(2):149–75.

14. Milner AM, Brown LE, Hannah DM. Hydroecological response of river systems to shrinking glaciers. Hydrological Processes. 2009;23(1):62–77.

15. Hood E, Fellman J, Spencer RGM, Hernes PJ, Edwards R, D'Amore D, et al. Glaciers as a source of ancient and labile organic matter to the marine environment. Nature. 2009;462(7276):1044–U100. doi: 10.1038/nature08580 20033045

16. Fellman JB, Spencer RGM, Hernes PJ, Edwards RT, D'Amore DV, Hood E. The impact of glacier runoff on the biodegradability and biochemical composition of terrigenous dissolved organic matter in near-shore marine ecosystems. Marine Chemistry. 2010;121(1–4):112–22.

17. Schroth AW, Crusius J, Chever F, Bostick BC, Rouxel OJ. Glacial influence on the geochemistry of riverine iron fluxes to the Gulf of Alaska and effects of deglaciation. Geophys Res Lett. 2011;38.

18. O'Neel S, Hood E, Bidlack AL, Fleming SW, Arimitsu ML, Arendt A, et al. Icefield-to-ocean linkages across the northern Pacific coastal temperate rainforest ecosystem. Bioscience. 2015;65(5):499–512.

19. Deluca TH, Boisvenue C. Boreal forest soil carbon: distribution, function and modelling. Forestry. 2012;85(2):161–84.

20. Fenner N, Freeman C, Lock MA, Harmens H, Reynolds B, Sparks T. Interactions between elevated CO2 and warming could amplify DOC exports from peatland catchments. Environmental Science & Technology. 2007;41(9):3146–52.

21. Yoshikawa K, Bolton WR, Romanovsky VE, Fukuda M, Hinzman LD. Impacts of wildfire on the permafrost in the boreal forests of Interior Alaska. J Geophys Res-Atmos. 2002;108(D1).

22. Neff JC, Finlay JC, Zimov SA, Davydov SP, Carrasco JJ, Schuur EAG, et al. Seasonal changes in the age and structure of dissolved organic carbon in Siberian rivers and streams. Geophys Res Lett. 2006;33(23).

23. Wickland KP, Aiken GR, Butler K, Dornblaser MM, Spencer RGM, Striegl RG. Biodegradability of dissolved organic carbon in the Yukon River and its tributaries: Seasonality and importance of inorganic nitrogen. Global Biogeochemical Cycles. 2012;26.

24. Black T, Den Hartog G, Neumann H, Blanken P, Yang P, Russell C, et al. Annual cycles of water vapour and carbon dioxide fluxes in and above a boreal aspen forest. Glob Change Biol. 1996;2(3):219–29.

25. Litvak M, Miller S, Wofsy SC, Goulden M. Effect of stand age on whole ecosystem CO2 exchange in the Canadian boreal forest. Journal of Geophysical Research: Atmospheres (1984–2012). 2003;108(D3).

26. Aiken GR, Spencer RGM, Striegl RG, Schuster PF, Raymond PA. Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin. Global Biogeochemical Cycles. 2014;28(5):525–37.

27. O'Donnell JA, Aiken GR, Kane ES, Jones JB. Source water controls on the character and origin of dissolved organic matter in streams of the Yukon River basin, Alaska. J Geophys Res-Biogeosci. 2010;115.

28. Wickland KP, Neff JC, Aiken GR. Dissolved organic carbon in Alaskan boreal forest: Sources, chemical characteristics, and biodegradability. Ecosystems. 2007;10(8):1323–40.

29. Kothawala DN, Stedmon CA, Muller RA, Weyhenmeyer GA, Kohler SJ, Tranvik LJ. Controls of dissolved organic matter quality: evidence from a large-scale boreal lake survey. Glob Change Biol. 2014;20(4):1101–14.

30. Balcarczyk KL, Jones JB Jr., Jaffe R, Maie N. Stream dissolved organic matter bioavailability and composition in watersheds underlain with discontinuous permafrost. Biogeochemistry. 2009;94(3):255–70.

31. Mann PJ, Davydova A, Zimov N, Spencer RGM, Davydov S, Bulygina E, et al. Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin. J Geophys Res-Biogeosci. 2012;117.

32. Cory RM, McKnight DM. Fluorescence spectroscopy reveals ubiquitous presence of oxidized and reduced quinones in dissolved organic matter. Environmental Science & Technology. 2005;39(21):8142–9.

33. McKnight DM, Boyer EW, Westerhoff PK, Doran PT, Kulbe T, Andersen DT. Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity. Limnology and Oceanography. 2001 Jan;46(1):38–48.

34. Vidon P, Carleton W, Mitchell MJ. Spatial and temporal variability in stream dissolved organic carbon quantity and quality in an Adirondack forested catchment. Appl Geochem. 2014;46:10–8.

35. Ohno T. Fluorescence inner-filtering correction for determining the humification index of dissolved organic matter. Environmental science & technology. 2002 Feb 15;36(4):742–6.

36. Murphy KR, Stedmon CA, Graeber D, Bro R. Fluorescence spectroscopy and multi-way techniques. PARAFAC. Analytical Methods. 2013;5(23):6557–66.

37. Stedmon CA, Bro R. Characterizing dissolved organic matter fluorescence with parallel factor analysis: a tutorial. Limnology and Oceanography: Methods. 2008 Nov;6(11):572–9.

38. Murphy KR, Stedmon CA, Graeber D, Bro R. Fluorescence spectroscopy and multi-way techniques. PARAFAC. Analytical Methods. 2013;5(23):6557–66.

39. Baldocchi DD, Hicks BB, Meyers TP. Measuring biosphere-atmosphere exchanges of biologically related gases with micrometeorological methods. Ecology. 1988;69(5):1331–40.

40. Aubinet M, Vesala T, Papale D, editors. Eddy Covariance A Practical Guide to Measurement and Data Analysis: Springer Verlag; 2012.

41. Vickers D, Mahrt L. Quality control and flux sampling problems for tower and aircraft data. J Atmos Ocean Technol. 1997;14(3):512–26.

42. Wilczak J, Oncley S, Stage S. Sonic Anemometer Tilt Correction Algorithms. Boundary-Layer Meteorology. 2001;99(1):127–50.

43. Webb EK, Pearman GI, Leuning R. Correction of flux measurements for density effects due to heat and water-vapor transfer. Quarterly Journal of the Royal Meteorological Society. 1980;106(447):85–100.

44. Burba G, Schmidt A, Scott RL, Nakai T, Kathilankal J, Fratini G, et al. Calculating CO2 and H2O eddy covariance fluxes from an enclosed gas analyzer using an instantaneous mixing ratio. Glob Change Biol. 2012;18(1):385–99.

45. Ibrom A, Dellwik E, Larsen SE, Pilegaard KIM. On the use of the Webb–Pearman–Leuning theory for closed-path eddy correlation measurements. Tellus B. 2007;59(5):937–46.

46. Moncrieff J, Clement R, Finnigan J, Meyers T. Averaging, detrending, and filtering of eddy covariance time series. In: Lee X, Massman W, Law B, editors. Handbook of Micrometeorology. Dordrecht: Kluwer Academic Publishers; 2004.

47. Moncrieff J, Massheder JM, de Bruin H, Elbers J, Friborg T, Heusinkveld B, et al. A system to measure surface fluxes of momentum, sensible heat, water vapour and carbon dioxide. Journal of Hydrology. 1997;188–189(0):589–611.

48. Kljun N, Calanca P, Rotach M, Schmid H. A simple parameterisation for flux footprint predictions. Boundary-Layer Meteorology. 2004;112(3):503–23.

49. Mauder M, Foken T. Documentation and instruction manual of the eddy-covariance software package TK3. Arbeitsergebnisse: Univ. Bayreuth Abt. Mikrometeorologie, ISSN: 1614-89166; 2011.

50. Goulden ML, Munger JW, Fan S-M, Daube BC, Wofsy SC. Measurements of carbon sequestration by long-term eddy covariance: methods and a critical evaluation of accuracy. Global Change Biology. 1996;2(3):169–82.

51. Gu LH, Falge EM, Boden T, Baldocchi DD, Black TA, Saleska SR, et al. Objective threshold determination for nighttime eddy flux filtering. Agric For Meteorol. 2005;128(3–4):179–97.

52. Falge E, Baldocchi D, Olson R, Anthoni P, Aubinet M, Bernhofer C, et al. Gap filling strategies for defensible annual sums of net ecosystem exchange. Agric For Meteorol. 2001;107(1):43–69.

53. Moffat AM, Papale D, Reichstein M, Hollinger DY, Richardson AD, Barr AG, et al. Comprehensive comparison of gap-filling techniques for eddy covariance net carbon fluxes. Agric For Meteorol. 2007;147(3–4):209–32.

54. Reichstein M, Falge E, Baldocchi D, Papale D, Aubinet M, Berbigier P, et al. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology. 2005;11(9):1424–39.

55. Dutton A, Wilkinson BH, Welker JM, Bowen GJ, Lohmann KC. Spatial distribution and seasonal variation in O-18/O-16 of modern precipitation and river water across the conterminous USA. Hydrological Processes. 2005;19(20):4121–46.

56. Leffler AJ, Welker JM. Long-term increases in snow pack elevate leaf N and photosynthesis in Salix arctica: responses to a snow fence experiment in the High Arctic of NW Greenland. Environmental Research Letters. 2013;8(2):025023.

57. Welker JM. Isotopic (delta O-18) characteristics of weekly precipitation collected across the USA: an initial analysis with application to water source studies. Hydrological Processes. 2000;14(8):1449–64.

58. Alstad K, Welker J, Williams S, Trlica M. Carbon and water relations of Salix monticola in response to winter browsing and changes in surface water hydrology: an isotopic study using δ13C and δ18O. Oecologia. 1999;120(3):375–85. doi: 10.1007/s004420050870 28308014

59. Vachon RW, Welker JM, White JWC, Vaughn BH. Monthly precipitation isoscapes (delta O-18) of the United States: Connections with surface temperatures, moisture source conditions, and air mass trajectories. J Geophys Res-Atmos. 2010;115.

60. Jencso KG, McGlynn BL, Gooseff MN, Wondzell SM, Bencala KE, Marshall LA. Hydrologic connectivity between landscapes and streams: Transferring reach-and plot-scale understanding to the catchment scale. Water Resour Res. 2009;45.

61. Koch JC, Ewing SA, Striegl R, McKnight DM. Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA). Hydrogeol J. 2013;21(1):93–106.

62. Simmons T. Central Alaska Network flowing waters monitoring program: 2009 annual report. Natural Resource Technical Report NPS/CAKN/NRTR National Park Service Ft Collins, Colorado. 2011;454.

63. Fichot CG, Benner R. A novel method to estimate DOC concentrations from CDOM absorption coefficients in coastal waters. Geophys Res Lett. 2011;38.

64. Downing BD, Boss E, Bergamaschi BA, Fleck JA, Lionberger MA, Ganju NK, et al. Quantifying fluxes and characterizing compositional changes of dissolved organic matter in aquatic systems in situ using combined acoustic and optical measurements. Limnol Oceanogr Meth. 2009;7:119–31.

65. Wilson HF, Saiers JE, Raymond PA, Sobczak WV. Hydrologic Drivers and Seasonality of Dissolved Organic Carbon Concentration, Nitrogen Content, Bioavailability, and Export in a Forested New England Stream. Ecosystems. 2013;16(4):604–16.

66. Downing BD, Pellerin BA, Bergamaschi BA, Saraceno JF, Kraus TEC. Seeing the light: The effects of particles, dissolved materials, and temperature on in situ measurements of DOM fluorescence in rivers and streams. Limnol Oceanogr Meth. 2012;10:767–75.

67. Fellman JB, Hood E, Spencer RGM. Fluorescence spectroscopy opens new windows into dissolved organic matter dynamics in freshwater ecosystems: A review. Limnol Oceanogr. 2010;55(6):2452–62.

68. Coble PG. Characterization of marine and terrestrial DOM in seawater using excitation-emission matrix spectroscopy. Marine chemistry. 1996 Jan 1;51(4):325–46.

69. Coble PG, Green SA, Blough NV, Gagosian RB. Characterization of dissolved organic matter in the Black Sea by fluorescence spectroscopy. Nature. 1990 Nov;348(6300):432.

70. Stedmon CA, Markager S, Bro R. Tracing dissolved organic matter in aquatic environments using a new approach to fluorescence spectroscopy. Marine Chemistry. 2003 Aug 1;82(3–4):239–54.

71. Williams CJ, Yamashita Y, Wilson HF, Jaffé R, Xenopoulos MA. Unraveling the role of land use and microbial activity in shaping dissolved organic matter characteristics in stream ecosystems. Limnology and Oceanography. 2010 May;55(3):1159–71.

72. Yamashita Y, Kloeppel BD, Knoepp J, Zausen GL, Jaffé R. Effects of watershed history on dissolved organic matter characteristics in headwater streams. Ecosystems. 2011 Nov 1;14(7):1110–22.

73. Yamashita Y, Boyer JN, Jaffé R. Evaluating the distribution of terrestrial dissolved organic matter in a complex coastal ecosystem using fluorescence spectroscopy. Continental shelf research. 2013 Sep 1;66:136–44.

74. Murphy KR, Stedmon CA, Wenig P, Bro R. OpenFluor–an online spectral library of auto-fluorescence by organic compounds in the environment. Analytical Methods. 2014;6(3):658–61.

75. Tanaka K, Kuma K, Hamasaki K, Yamashita Y. Accumulation of humic-like fluorescent dissolved organic matter in the Japan Sea. Scientific reports. 2014 Jul 16;4:5292. doi: 10.1038/srep05292 25028129

76. Kulkarni HV, Mladenov N, Datta S, Chatterjee D. Influence of monsoonal recharge on arsenic and dissolved organic matter in the Holocene and Pleistocene aquifers of the Bengal Basin. Science of The Total Environment. 2018 Oct 1;637:588–99. doi: 10.1016/j.scitotenv.2018.05.009 29754092

77. Stedmon CA, Thomas DN, Papadimitriou S, Granskog MA, Dieckmann GS. Using fluorescence to characterize dissolved organic matter in Antarctic sea ice brines. Journal of Geophysical Research: Biogeosciences. 2011 Sep;116(G3). doi: 10.1029/2011jg001641

78. Yamashita Y, Boyer JN, Jaffé R. Evaluating the distribution of terrestrial dissolved organic matter in a complex coastal ecosystem using fluorescence spectroscopy. Continental shelf research. 2013 Sep 1;66:136–44.

79. Chen M, Kim SH, Jung HJ, Hyun JH, Choi JH, Lee HJ, Huh IA, Hur J. Dynamics of dissolved organic matter in riverine sediments affected by weir impoundments: Production, benthic flux, and environmental implications. Water research. 2017 Sep 15;121:150–61. doi: 10.1016/j.watres.2017.05.022 28527389

80. O'Donnell JA, Aiken GR, Butler KD, Guillemette F, Podgorski DC, Spencer RG. DOM composition and transformation in boreal forest soils: The effects of temperature and organic‐horizon decomposition state. Journal of Geophysical Research: Biogeosciences. 2016 Oct;121(10):2727–44.

81. Stedmon CA, Thomas DN, Papadimitriou S, Granskog MA, Dieckmann GS. Using fluorescence to characterize dissolved organic matter in Antarctic sea ice brines. Journal of Geophysical Research: Biogeosciences. 2011 Sep;116(G3). doi: 10.1029/2011jg001641

82. Hernes PJ, Bergamaschi BA, Eckard RS, Spencer RG. Fluorescence‐based proxies for lignin in freshwater dissolved organic matter. Journal of Geophysical Research: Biogeosciences. 2009 Dec 1;114(G4).

83. Wünsch UJ, Murphy KR, Stedmon CA. Fluorescence quantum yields of natural organic matter and organic compounds: Implications for the fluorescence-based interpretation of organic matter composition. Frontiers in Marine Science. 2015 Nov 13;2:98.

84. Carey SK. Dissolved organic carbon fluxes in a discontinuous permafrost subarctic alpine catchment. Permafrost Periglacial Process. 2003;14(2):161–71.

85. Fraser CJD, Roulet NT, Moore TR. Hydrology and dissolved organic carbon biogeochemistry in an ombrotrophic bog. Hydrological Processes. 2001;15(16):3151–66.

86. Prokushkin AS, Kajimoto T, Prokushkin SG, McDowell WH, Abaimov AP, Matsuura Y. Climatic factors influencing fluxes of dissolved organic carbon from the forest floor in a continuous-permafrost Siberian watershed. Can J For Res-Rev Can Rech For. 2005;35(9):2130–40.

87. Goulden ML, McMillan A, Winston GC, Rocha AV, Manies KL, Harden JW, et al. Patterns of NPP, GPP, respiration, and NEP during boreal forest succession. Glob Change Biol. 2011;17(2):855–71.

88. Goulden M, Wofsy S, Harden J, Trumbore S, Crill P, Gower S, et al. Sensitivity of boreal forest carbon balance to soil thaw. Science. 1998;279(5348):214–7. doi: 10.1126/science.279.5348.214 9422691

89. Dios VR, Goulden ML, Ogle K, Richardson AD, Hollinger DY, Davidson EA, et al. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems. Glob Change Biol. 2012;18(6):1956–70.

90. Froelich N, Croft H, Chen JM, Gonsamo A, Staebler RM. Trends of carbon fluxes and climate over a mixed temperate–boreal transition forest in southern Ontario, Canada. Agric For Meteorol. 2015;211:72–84.

91. Pelletier L, Strachan IB, Roulet NT, Garneau M, Wischnewski K. Effect of open water pools on ecosystem scale surface-atmosphere carbon dioxide exchange in a boreal peatland. Biogeochemistry. 2014:1–14.

92. Rupp TS, Chen X, Olson M, McGuire AD. Sensitivity of simulated boreal fire dynamics to uncertainties in climate drivers. Earth Interactions. 2007;11(3):1–21.

93. Duffy PA, Walsh JE, Graham JM, Mann DH, Rupp TS. Impacts of large-scale atmospheric-ocean variability on Alaskan fire season severity. Ecological Applications. 2005;15(4):1317–30.

94. Spotila JA, Buscher JT, Meigs AJ, Reiners PW. Long-term glacial erosion of active mountain belts: Example of the Chugach St. Elias Range, Alaska. Geology. 2004;32(6):501–4.


Článek vyšel v časopise

PLOS One


2019 Číslo 11
Nejčtenější tento týden
Nejčtenější v tomto čísle
Kurzy

Zvyšte si kvalifikaci online z pohodlí domova

KOST
Koncepce osteologické péče pro gynekology a praktické lékaře
nový kurz
Autoři: MUDr. František Šenk

Sekvenční léčba schizofrenie
Autoři: MUDr. Jana Hořínková

Hypertenze a hypercholesterolémie – synergický efekt léčby
Autoři: prof. MUDr. Hana Rosolová, DrSc.

Svět praktické medicíny 5/2023 (znalostní test z časopisu)

Imunopatologie? … a co my s tím???
Autoři: doc. MUDr. Helena Lahoda Brodská, Ph.D.

Všechny kurzy
Kurzy Podcasty Doporučená témata Časopisy
Přihlášení
Zapomenuté heslo

Zadejte e-mailovou adresu, se kterou jste vytvářel(a) účet, budou Vám na ni zaslány informace k nastavení nového hesla.

Přihlášení

Nemáte účet?  Registrujte se

#ADS_BOTTOM_SCRIPTS#