Meiobenthos with special reference to free-living marine nematodes as bioindicators for different mangrove types in Can Gio Biosphere Reserve, Vietnam [Elektronische Ressource] / Lai Phu Hoang

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• Biologie

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• Publié par: universitat_bremen
• Publié le: 01 janvier 2007
• Nombre de lectures: 54
• Langue: English
• Poids de l'ouvrage: 10 Mo

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Meiobenthos with special reference to
free-living marine nematodes as bioindicators
for different mangrove types in Can Gio
Biosphere Reserve, Vietnam
Lai Phu Hoang
Thesis submitted in partial fulfilment of the requirements for
the degree of Doctor of Natural Sciences
Faculty 2 (Biology/Chemistry)
University of Bremen
Bremen 2007 Supervisor: Prof. Dr. Ulrich Saint Paul, ZMT
Co-supervisor: DSc. Nguyen Vu Thanh, IEBRÕ
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ACKNOWLEDGEMENTACKNOWLEDGEMENT
First of all, I would like to express my sincere gratitude to Prof. Dr. Saint-Paul, my
supervisor, for the very valuable help and for providing such excellent working
conditions during my study research.
My great gratitude is also extended to DSc. Nguyen Vu Thanh, my co-supervisor, for
all professional guidance and all other efforts made for me to achieve successful
research results.
I am very grateful to Dr. Dietrich Blome, for his enthusiastic help in nematode
identification and many useful professional documents when I worked at the ZMT.
I am greatly indebted to AssocProf.Dr. Nguyen Ngoc Chau, and my colleagues at the
Department of Nematology, IEBR, who helped, supported and encouraged me during
my study research.
I would like to express thanks to Dr. Tran Triet, Dr Le Xuan Thuyen, Dr Vien Ngoc
Nam, and my colleagues at the University of Natural Sciences and the Institute of
Tropical Biology for the kind help during my sampling expeditions in Can Gio
Biosphere Reserve and while working in Ho Chi Minh City.
I am greatly indebted to Stefanie Bröhl for her help from the first time I came to the
laboratory to the time I completed my thesis.
I am very thankful to Gabriele Boehme and Silke Meyerholz for generosity,
hospitality and the valuable help with administrative affairs.
I would like to express my thanks to Tina Dohna for her useful help in reviewing the
English manuscript and for translating the abstract into German.
I would like to express my sincere thanks to Prof .Dr. Venu Ittekkot, Priv-Doz.Dr.
Rubén Lara, and all my colleagues at the ZMT, who shared their knowledge and
experience with me, creating an interesting atmosphere throughout my stay.
My grateful appreciation is extended to the Deutsche Forschungsgemeinschaft (DFG),
and Ministry of Science and Technology (MOST), Vietnam for their financial support
of the Can Gio Project.
I would also like to thank my Vietnamese friends in Bremen, who helped me
whenever needed and created a home-hearted atmosphere abroad.
Cu i cùng, tôi xin g i l i c m n n cha m , các thành viên trong gia ình, b n bè,
và nh ng ng i thân luôn quan tâm ng viên tôi hoàn thành lu n án này!
má³
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CONTENTSCONTENTS
List of Figures...............................................................................................................iv
List of Tables ................................................................................................................vi
Abstract....................................................................................................................... vii
Zusammenfassung ........................................................................................................ix
Tóm t t........................................................................................................................ xii
1 INTRODUCTION ......................................................................................................1
1.1 Statement of the problem.....................................................................................1
1.2 Meiobenthos and disturbance assessment............................................................3
1.2.1 Meiobenthos as bioindicators of habitat change...........................................3
1.2.2 Methods for the assessment of disturbance using meiobenthos ...................4
1.2.3 Meiobenthos studies in mangroves...............................................................5
1.3 Focus and objectives............................................................................................6
2 MATERIALS AND METHODS ...............................................................................8
2.1 Study area ............................................................................................................8
2.1.1 Location ........................................................................................................8
2.1.2 Natural conditions and vegetation ................................................................8
2.2 Sampling and data collection.............................................................................10
2.2.1 Sampling times and sites/stations ...............................................................10
2.2.2 Sampling, extraction and preparation of permanent slides.........................10
2.2.3 Data collection ............................................................................................12
2.3 Data analysis......................................................................................................13
3 RESULTS .................................................................................................................14
3.1 Abiotic factors....................................................................................................14
3.2 Meiobenthos.......................................................................................................14
3.2.1 Meiobenthic composition in three creeks ...................................................14
3.2.2 Changes in meiobenthic abundance in Rach Oc creek...............................15
3.2.2.1 Total meiobenthos................................................................................15
3.2.2.2 Nematodes ...........................................................................................16
3.2.2.3 Copepods and nauplii...........................................................................19
3.2.2.4 Foraminifera.........................................................................................20
3.2.2.5 Other less abundant groups..................................................................20
3.2.2.6 Variation of the nematodes/copepods ratio (N/C) ...............................21
3.2.3 Correlation with abiotic fators ....................................................................21
3.3 Nematode assemblage........................................................................................22
3.3.1 Taxonomy ...................................................................................................22
3.3.1.1 List of species ......................................................................................22
3.3.1.2 Family Leptolaimidae Örley, 1880......................................................22
3.3.2 Ecology .......................................................................................................42
3.3.2.1 Nematode composition ........................................................................42 iii
3.3.2.2 Age and sex composition .................................................................... 44
3.3.2.3 Trophic structure ................................................................................. 46
3.3.2.4 Nematode diversity ............................................................................. 48
3.3.2.5 Multivariate analysis ........................................................................... 52
3.4 Meiobenthos and nematode assemblage for differentiation of mangrove types63
4 DISCUSSION .......................................................................................................... 66
4.1 Meiobenthos...................................................................................................... 66
4.1.1 Composition and density of total meiobenthos.......................................... 66
4.1.2 Abundance of major meiobenthic groups .................................................. 69
4.2 Nematode assemblage....................................................................................... 70
4.2.1 Taxonomy .................................................................................................. 70
4.2.2 Nematode community structure ................................................................. 74
4.2.2.1 Nematode composition........................................................................ 74
4.2.2.2 Age and sex composition .................................................................... 76
4.2.2.3 Trophic structure ................................................................................. 76
4.2.2.4 Nematode diversity ............................................................................. 78
4.2.2.5 Community structures ......................................................................... 79
5 CONCLUSIONS...................................................................................................... 81
REFERENCES............................................................................................................ 83
APPENDIX..................................................