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Kaiho Super Science High School
Mangrove ecology: application of fatty acid biomarkers as trophic tracers in the
ecosystem
JSPS
Prosper Mfilinge
Advisor: Prof. Makoto Tsuchiya
Self Introduction
What are mangroves?
“Tropical & sub-tropical trees restricted to intertidal and adjacent communities” and adapted to live in salt water
Tropical:熱帯のIntertidal:潮間帯Adjacent:付近の
Mangal
Mangal “community (all animals and plants) that contains mangrove plants”
Mangrove ecology
“The study of interrelationships between living organisms and their environment”
Ecosystem “ecological system made up of various communities of organisms interacting with one another and influenced by the environment”
Interrelationships:相互関係Interact with:~と互いに影響し合う
Ecological significance of mangroves
Provide food, shelter, protection and nurseries for many species of fish
Sustain high biodiversity
Support aquatic and terrestrialfood webs
e.g. Birds, insects, reptiles which come to feed in mangroves
Terrestrial:陸生の
Source: ISME 1995
Ecological significance of mangroves
Mangrove assimilated energy and nutrients exported to surrounding coral reefs through export and food chain
Assimilate:吸収する nutrient:栄養分
Mangrove trophic ecology
Food chain/ food web(Energy transferred by feeding and nutrient recycled)
Examples of mangrove food chains in Okinawa mangroves
Example of food pyramid in Okinawa mangroves
Bacteria
3rd trophic level(Carnivores)
2nd trophic level(Herbivores)
1st trophic level(Primary producers)
In order to study trophic (food chains) relationships we need biomarkers
Trophic:栄養段階
What are biomarkers
Chemical compound/compounds characteristic of an organism, which can be used to indicate the presence of the organism/plant in the environment and to estimate its biomass
e.g. bacteria, diatoms, dinoflagellates, mangrove, algae
Estimate:推定する
Characteristic of a useful biomarker
Must be synthesized at low trophic levels e.g. mangrove and remain unchanged when transferred to higher trophic levels 3rd trophic level
(Carnivores)
2nd trophic level(Herbivores)
1st trophic level(Primary producers)
Why do we use biomarkers?
Because it is difficulty to identify types of food in stomachs once ingested
Or identify types of organic material in sediments after decay
To find links between ecosystems
Ingest:消化する decay:腐敗する
Sea-grasses Coral reefsMangroves
Examples of biomarkers used in marine ecology
Stable isotopes e.g. carbon (13C), nitrogen (15N), sulfur etc
Lipids e.g. fatty acids
fatty acids:脂肪酸 carbon:炭素 nitrogen:窒素
Classes of lipids
Phospholipids (Polar lipids), Sterols, Triacylglycerols, Free fatty acids, Waxes, Wax esters
What are fatty acids?
Major components of lipidsEssential components of all living cells and cell membrane lipids
Source of metabolic energy From http://www.oup.co.uk
Plant cell Animal cell
Fatty acids
cell membrane:細胞膜Metabolic: 代謝の
General features of a fatty acid structure
A long hydrocarbon chain ( 4-32 carbons), 14-30 is most common
A carboxylic acid group COOH
Hydrocarbon chain Carboxylicacid group
Classification of fatty acids
Based on the number of double bonds
CH3(CH2)14COOH
0 double bonds: Saturated fatty acids e.g. 16:0 (Palmitic acid)
One double bond: Monounsaturated fatty acids e.g. 16:1ω7 (Palmitoleic acid)
CH3(CH2)5CH=CH(CH2)7COOH
Palmitic acid:パルミチン酸 Monounsaturated:一価不飽和
Classification of fatty acids
2 or more double bonds: Polyunsaturated fatty acids e.g. 18:2ω6 (linoleic acid)
CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH
Branched fatty acids (odd and even number)
CH3CH2CH(CH2)10COOH
H3C
CH3CH2(CH2)11COOH
H3Ce.g. 15:0 iso
15:anteiso
Polyunsaturated:多価不飽和 Branched:分枝
Nomenclature of Fatty acids
There are 4 common naming systems
Palmitic acid Hexadecanoic acid 16:0 16:0
1) Trivial 2) IUPAC 3)Carboxylic reference 4) ω-reference
Oleic acid 9-Octadecenoic acid 18:1∆9 18:1ω9
Linoleic acid 9,12-Octadecenoic acid 18:2∆9,12 18:2ω6
Palmitic acid:パルミチン酸
ω & ∆ Designation
ω designated as X:YωZ Where X= number of carbon atoms Y= number of double bonds Z= Position of double bond from the terminal methyl group e.g. 16:0 and 18:2ω6
double bonds:二重結合 methyl:メチル基 CH3
CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH(∆designated)
CH3(CH2)14COOH 16:0
18:2ω6 (ωdesignated)
18:2 ∆9,12
Why two common designations?
The ω -designation is useful because it allows nutritionists and ecologists to track families of fatty acids or link diet with tissue fatty acid composition
The ∆-designation is useful to describe the biochemical reactions
Fatty acid metabolism
Synthesis in plants..where? in chloroplast
Synthesis:生合成Chloroplast:葉緑体
From http://www.oup.co.uk/oxed/children/oise/pictures/nature/plantcell/
Fatty acid metabolism
Smooth ER
Rough ER
Synthesis in animalsWhere? Phospholipids of smooth
endoplasmic reticullum(ER)
endoplasmic reticullum:小胞体
http://www.oup.co.uk/oxed/children/oise/pictures/nature/animalcell/From
Fatty acid metabolism
Fatty acids are synthesized from acetyl-CoA
First products of biosynthesis16:0
Subsequent metabolism and modification occur in endoplasmic reticulum
From http://www.oup.co.uk/oxed/children/oise/pictures/nature/plantcell/
Subsequent:次のModification:変化 Endoplasmic:小胞体 Reticulum:網状組織
Why do we use fatty acids as biomarkers
High structural diversity
High taxonomic specificity e.g.
Specificity:特異性
Terebralia palustris Terebralia sulcata
FA distributions in green and yellow leaves
Green leaves
16:0
16:1ω
717
:0
18:0
22:0
18:1ω
9 18:2ω
6
18:3ω
320
:0
24:0
28:0
26:0
23:0
14:0
% o
f tot
al F
As
Yellow leaves
16:0
16:1ω
717
:018
:0
22:0
18:1ω
918
:2ω
618
:3ω
320
:0 24:0
28:0
26:023:0
14:0
30:0
% o
f tot
al F
As
Even-Long chain FAs
FA distributions in decayed leaves and mangrove sediment
After 132 days
Mangrove sediments
18:0
18:2ω
6
16:0
16:1ω
717
:0
22:018
:3ω
3
23:0
14:0 28
:026:0
30:0
22:6ω
3
18:1ω
9/7
20:0
24:0
20:3ω
6
16:1ω
717
:0
22:0
23:0
14:0 28
:026:0
30:0
18:1ω
9/7
20:0
24:0
20:3ω
6
18:0
16:0
% o
f tot
al F
As
% o
f tot
al F
As
Even-Long chain FAsSediment:底質
FA should be transferred unchanged to high trophic level
26:028:030:032:0
15:0 iso; 15:0 anteiso; 17:0 iso17:0 anteiso; 18:1ω7
20:5ω3
18:4ω322:6ω3Bacteria
18:2ω618:3ω618:3ω3
Diet composition of gastropods
26:028:030:032:0
26:028:030:032:0
26:028:030:032:0
Diatoms (20:5ω3)
Algae 18:2ω618:3ω618:3ω3
Dinoflaggelates18:4ω322:6ω3
Bacteria 15:0 iso; 15:0 anteiso; 17:0 iso17:0 anteiso; 18:1ω70
2
4
6
Oura Okukubi Nagura Komi Urauchi
Dinoflagellates Bacteria 18:1ω7
18:2ω618:3ω618:3ω320:5ω3
18:4ω322:6ω3
15:0 iso15:0 anteiso17:0 iso17:0 anteiso; 18:1ω7
0
4
8
12
Oura Okukubi Nagura Komi Urauchi
Mangrove Macroalgae Diatoms
%
High
Low
Low
High
%
Fatty acid as indicators of sources & fate of organic matter
Mfilinge et al., (2005) Estuarine Coastal and Shelf Science, Vol. 63, 301-313
mangrove
Sand flat
Sand flat
Mud flat
Remarks and conclusions
Vascular plants (mangrove and terrestrial plants) share common fatty acid markers (even long chain FAs). Therefore it is impossible to distinguish between mangrove and terrestrial plants organic matter inputs.
Ongoing research: Find new fatty acid biomarkers that can distinguish between mangrove and terrestrial plants.
Vascular plants:維管束植物
Fungi:菌類
Acknowledgements
Prof. Makoto Tsuchiya
For his kind advice throughout my studies in Japan
Japan Society for the Promotion of Science (JSPS)
For the post-doctoral fellowship
THANK YOU