The role of sympagic meiofauna in Arctic and Antarctic sea-ice food webs [Elektronische Ressource] / submitted by Maike Kramer

Sujets

• Biologie

Informations

• Publié par: christian-albrechts-universitat_zu_kiel
• Publié le: 01 janvier 2010
• Nombre de lectures: 32
• Langue: English
• Poids de l'ouvrage: 19 Mo

Extrait

Institute for Polar Ecology (IPÖ),
Christian-Albrechts Universität zu Kiel
The role of sympagic meiofauna in
Arctic and Antarctic
sea-ice food webs
Dissertationthesis
forgainingthedoctoraldegree
oftheFacultyofMathematicsandScience
oftheChristian-Albrechts-UniversitätzuKiel
Dissertation
zurErlangungdesDoktorgrades
derMathematisch-NaturwissenschaftlichenFakultät
derChristian-Albrechts-UniversitätzuKiel
Submittedby
Vorgelegtvon
Maike Kramer
Kiel, 2010Supervising referee (Referentin): PD Dr. Iris Werner
Second referee (Korreferent): Prof. Dr. Ulrich Sommer
Date of oral examination (Tag der mündlichen Prüfung): January 31, 2011
Approved for print (zum Druck genehmigt): February 16, 2011
Gez. Prof. Dr. Lutz Kipp, DekanContents
Abstract xii
Zusammenfassung xiv
1 Introduction: The role of sympagic meiofauna in sea-ice food webs—
a three-method approach 1
1.1 Motivation and overview of my thesis . . . . . . . . . . . . . . . . . . . 1
1.2 Sea ice and sympagic communities . . . . . . . . . . . . . . . . . . . . . 2
1.3 Sympagic meiofauna in sea-ice food webs . . . . . . . . . . . . . . . . . 4
1.4 The three-method approach of this study . . . . . . . . . . . . . . . . . . 5
1.5 Publications included in or related to my thesis . . . . . . . . . . . . . . 7
2 Antarctic sympagic meiofauna in winter: comparing diversity, abun-
dance and biomass between perennially and seasonally ice-covered
regions 9
2.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 Field work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2 Determination of environmental parameters . . . . . . . . . . . . 14
2.3.3 Meiofauna community analyses . . . . . . . . . . . . . . . . . . 14
2.3.4 Comparison of the two study areas . . . . . . . . . . . . . . . . . 16
2.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4.1 Environmental parameters . . . . . . . . . . . . . . . . . . . . . 17
2.4.2 Meiofauna communities . . . . . . . . . . . . . . . . . . . . . . 19
2.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.5.1 Significance of old ice and perennial ice cover to sympagic meta-
zoan meiofauna . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.5.2 High meiofauna diversity, abundance and biomass in winter . . . 29
2.5.3 Occurrence of meiofauna internal and surface communities in
winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.5.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.S Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.S1 Stations and samples . . . . . . . . . . . . . . . . . . . . . . . . 33
2.S2 Meiofauna carbon content . . . . . . . . . . . . . . . . . . . . . 34
2.S3 Details on statistical procedures . . . . . . . . . . . . . . . . . . 36
2.S4 Morphology and taxonomy . . . . . . . . . . . . . . . . . . . . . 37
2.S5 Vertical distribution . . . . . . . . . . . . . . . . . . . . . . . . . 41
vContents
3 Brackish meltponds on Arctic sea ice—a new habitat for marine meta-
zoans 45
3.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.3 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.S Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.S1 Meltpond sampling stations . . . . . . . . . . . . . . . . . . . . 53
3.S2 Environmental conditions in meltponds . . . . . . . . . . . . . . 54
3.S3 Meltpond depth from literature . . . . . . . . . . . . . . . . . . . 56
4 Trophic positions of Arctic and Antarctic sympagic meiofauna and its
role in cryo-pelagic coupling identified by stable isotopes and fatty
acids 57
4.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.3 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.3.1 Sampling and sample processing . . . . . . . . . . . . . . . . . . 59
4.3.2 Stable isotope analyses and carbon and nitrogen contents . . . . . 61
4.3.3 Lipid, fatty acid and fatty alcohol analyses . . . . . . . . . . . . 64
4.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.4.1 C:N ratios and stable isotopes . . . . . . . . . . . . . . . . . . . 65
4.4.2 Lipid and wax ester contents and fatty acids . . . . . . . . . . . . 69
4.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4.5.1 Complexity of the sympagic food web . . . . . . . . . . . . . . . 72
4.5.2 Distinction of feeding grounds based on the stable isotope data . . 76
4.5.3 Cryo-pelagic coupling and the role of meltponds . . . . . . . . . 78
4.5.4 Suitability of stable isotope and fatty acid analyses to sympagic
meiofauna studies . . . . . . . . . . . . . . . . . . . . . . . . . . 80
4.5.5 Conclusions and outlook . . . . . . . . . . . . . . . . . . . . . . 81
4.6 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
4.S Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
4.S1 Stations and samples . . . . . . . . . . . . . . . . . . . . . . . . 83
4.S2 Required sample size . . . . . . . . . . . . . . . . . . . . . . . . 84
4.S3 Blank correction . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.S4 Derivation of the two-source model . . . . . . . . . . . . . . . . 86
4.S5 Calculation of dry mass . . . . . . . . . . . . . . . . . . . . . . . 89
4.S6 Details on results from SI and FA . . . . . . . . . . . . . . . . . 90
5 Diets, ingestion rates and feeding impact of sympagic meiofauna
based on experiments 99
5.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.3 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.3.1 Sampling and sample processing . . . . . . . . . . . . . . . . . . 101
viContents
5.3.2 Determination of ice-algae biomass and abundance and biomass
of sympagic meiofauna . . . . . . . . . . . . . . . . . . . . . . . 102
5.3.3 Setup of feeding experiments . . . . . . . . . . . . . . . . . . . . 103
5.3.4 Evaluation of feeding experiments . . . . . . . . . . . . . . . . . 105
5.3.5 Assessment of impact . . . . . . . . . . . . . . . . . . . 107
5.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
5.4.1 Ice-algae biomass and meiofauna abundance and biomass . . . . 108
5.4.2 Experimental diets and non-quantitative observations . . . . . . . 111
5.4.3 Grazing rates and selectivity of Tisbe spp. . . . . . . . . . . . . . 111
5.4.4 Predation rates of Arctic and Antarctic sympagic meiofauna . . . 114
5.4.5 Feeding impact . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
5.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
5.5.1 Predation and flexible feeding strategies in sea ice . . . . . . . . . 121
5.5.2 Factors influencing ingestion rates: functional response, compe-
tition, size and taxa . . . . . . . . . . . . . . . . . . . . . . . . . 123
5.5.3 Low grazing and high predation impact . . . . . . . . . . . . . . 125
5.5.4 Potential of feeding experiments and modelling in sympagic meio-
fauna studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
5.6 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
5.7 Role of the funding source . . . . . . . . . . . . . . . . . . . . . . . . . 128
5.S Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
5.S1 Details on the determination of grazing rates . . . . . . . . . . . . 129
5.S2 on the of selectivity . . . . . . . . . 131
5.S3 Details on the of predation rates . . . . . . . . . . 132
5.S4 on the assessment of the feeding impact . . . . . . . . . . 133
5.S5 Details on the results of grazing experiments . . . . . . . . . . . 134
5.S6 on the of predation e . . . . . . . . . . 137
6 Synopsis 145
6.1 Complexity of sea-ice food webs . . . . . . . . . . . . . . . . . . . . . . 145
6.2 Feeding impact of sympagic meiofauna . . . . . . . . . . . . . . . . . . 148
6.3 Sympagic meiofauna feeding ecology and cryo-pelagic coupling . . . . . 150
6.4 meiofauna under global warming: impacts on the Arctic ma-
rine food web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
6.5 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
References I
Acknowledgements XXII
Danksagung XXVIII
Curriculum vitae XXXIV
Lebenslauf XXXVII