A study of carbon, nitrogen, and biogenic silica concentrations in Cyperus papyrus, the sedge dominating the permanent swamp of the Okavango Delta, Botswana, Africa
(2022) In Dissertations in Geology at Lund University GEOR02 20221Department of Geology
- Abstract (Swedish)
- Okawangodeltat är södra Afrikas största våtmark och en av världens minst påverkade våtmarker. Kunskapen om hur våtmarkssystemet fungerar är begränsad, särskilt vad gäller halter av näringsämnen och omsättning av näringsämnen i de dominerande våtmarksväxterna. I den här studien presenteras analyser av kol-
, kväve- och kiselhalter i Cyperus papyrus som är den dominerande akvatiska växten i stora delar av deltat. Papyrus samlades in från tre platser i den permanenta våtmarken i deltat. Material samlades in från växter med olika ålder,
från olika växtplatser och under hög- och lågvatten. Varje insamlad växt delades upp i: blomställningar, stammar, fjäll, rötter och jordstammar. Alla prover analyserades för halt av totalt kol, totalt kväve... (More) - Okawangodeltat är södra Afrikas största våtmark och en av världens minst påverkade våtmarker. Kunskapen om hur våtmarkssystemet fungerar är begränsad, särskilt vad gäller halter av näringsämnen och omsättning av näringsämnen i de dominerande våtmarksväxterna. I den här studien presenteras analyser av kol-
, kväve- och kiselhalter i Cyperus papyrus som är den dominerande akvatiska växten i stora delar av deltat. Papyrus samlades in från tre platser i den permanenta våtmarken i deltat. Material samlades in från växter med olika ålder,
från olika växtplatser och under hög- och lågvatten. Varje insamlad växt delades upp i: blomställningar, stammar, fjäll, rötter och jordstammar. Alla prover analyserades för halt av totalt kol, totalt kväve och kisel. Skillnader i
koncentration av näringsämnen från de olika växtdelarna analyserades med avseende på ålder, växtmiljö och vattenstånd. De högsta kvävehalterna uppmättes i blomställningar, rötter och jordstammar. Detta förklaras av att
blomställningar både är fotosyntetiserande och producerar blommor och frön, jordstammarna lagrar näring, och rötterna har ofta associerade kvävefixerande bakterier. Kvävehalten var också högre i juvenila växter, eftersom
växter har mer aktiv näringstransport under den första tillväxtfasen. Kvävehalterna var generellt högre under högvattenfasen, medan växtplatsens avstånd till strömfåran i deltat inte påverkade kvävehalten. Koncentrationen av
totalt kol låg mellan 39 och 43 procent med högst halter i blomställningar och jordstammar, och lägst i rötter. Halten totalt kol var inte korrelerad med växtmiljö eller vattenstånd. Andelen kisel var högst i äldre växter, vilket
beror på att växterna ackumulerar kisel under sin livstid. Kiselinnehållet var inte jämnt fördelat mellan olika växtdelar, sannolikt eftersom kisel fälls ut i större utsträckning i de delar som är påverkade av vattenförlust. Kiselhalten var högre vid högvatten än vid lågvatten, medan växtmiljön inte påverkade iselhalten. (Less) - Abstract
- The Okavango Delta is southern Africa’s greatest wetland and is among one of the most pristine wetlands in the world. There is moderate information about how this system functions, however, the research on nutrient concentrations and cycles is especially limited. This study provides new knowledge on the Okavango Delta by analysing samples of Cyperus papyrus, one of the main aquatic plants in the area. Total nitrogen (TN), total organic carbon (TOC), and biogenic silica (BSi) concentrations in papyrus were measured and examined. Papyrus was harvested from three sites in the permanent swamps of the Okavango Delta, and divided in the different organs: umbel, culm, scales, roots, and rhizome. The two methods used in this study are elemental... (More)
- The Okavango Delta is southern Africa’s greatest wetland and is among one of the most pristine wetlands in the world. There is moderate information about how this system functions, however, the research on nutrient concentrations and cycles is especially limited. This study provides new knowledge on the Okavango Delta by analysing samples of Cyperus papyrus, one of the main aquatic plants in the area. Total nitrogen (TN), total organic carbon (TOC), and biogenic silica (BSi) concentrations in papyrus were measured and examined. Papyrus was harvested from three sites in the permanent swamps of the Okavango Delta, and divided in the different organs: umbel, culm, scales, roots, and rhizome. The two methods used in this study are elemental combustion analysis for TN and TOC and wet chemical digestion for BSi. I investigated if there were differences in TOC, TN, and BSi
depending on the part of the plant, the age of the plant, the environment in which the plant was growing, and the flood period. The highest TN concentrations were found in umbels, rhizomes, and roots. Umbels function as both a photosynthetic organ and an inflorescence; rhizomes act as a storage for nutrients; and roots have been found to be colonized by N2-fixing bacteria. Moreover, TN concentrations in juvenile organs were higher than in mature ones. This was associated active translocation and recycling of nutrients in the first stages of growth of papyrus from mature to juvenile plants which then might cause a higher productivity in juvenile plants. The environment in which papyrus grows does not seem to influence TN concentrations, however, during high flood periods there was a higher TN amount in papyrus. The results of the study showed TOC concentrations between 39-43%, the highest concentrations were found in umbels and rhizomes and the lowest in the roots. Statistical analyses on TOC concentrations comparing the growing sites and the flood periods did not give any significant results for any part of papyrus. Lastly, the highest BSi concentrations were found in mature organs since silica is accumulated inside the plant throughout its life. BSi was not uniformly distributed among the different organs, possibly because of a passive transport of dissolved silica through the transpiration system and deposited in regions mostly affected by
water loss. The growing site does not seem to influence BSi concentrations in papyrus. However, BSi in rhizomes was twice as high during high flood periods than during flood recession. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9088635
- author
- Lodi, Giulia LU
- supervisor
-
- Daniel Conley LU
- Karl Ljung LU
- Johanna Stadmark LU
- organization
- course
- GEOR02 20221
- year
- 2022
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Okavango Delta, papyrus, total nitrogen, total organic carbon, biogenic silica
- publication/series
- Dissertations in Geology at Lund University
- report number
- 639
- language
- English
- id
- 9088635
- date added to LUP
- 2022-06-15 09:59:22
- date last changed
- 2023-06-30 03:42:00
@misc{9088635,
abstract = {{The Okavango Delta is southern Africa’s greatest wetland and is among one of the most pristine wetlands in the world. There is moderate information about how this system functions, however, the research on nutrient concentrations and cycles is especially limited. This study provides new knowledge on the Okavango Delta by analysing samples of Cyperus papyrus, one of the main aquatic plants in the area. Total nitrogen (TN), total organic carbon (TOC), and biogenic silica (BSi) concentrations in papyrus were measured and examined. Papyrus was harvested from three sites in the permanent swamps of the Okavango Delta, and divided in the different organs: umbel, culm, scales, roots, and rhizome. The two methods used in this study are elemental combustion analysis for TN and TOC and wet chemical digestion for BSi. I investigated if there were differences in TOC, TN, and BSi
depending on the part of the plant, the age of the plant, the environment in which the plant was growing, and the flood period. The highest TN concentrations were found in umbels, rhizomes, and roots. Umbels function as both a photosynthetic organ and an inflorescence; rhizomes act as a storage for nutrients; and roots have been found to be colonized by N2-fixing bacteria. Moreover, TN concentrations in juvenile organs were higher than in mature ones. This was associated active translocation and recycling of nutrients in the first stages of growth of papyrus from mature to juvenile plants which then might cause a higher productivity in juvenile plants. The environment in which papyrus grows does not seem to influence TN concentrations, however, during high flood periods there was a higher TN amount in papyrus. The results of the study showed TOC concentrations between 39-43%, the highest concentrations were found in umbels and rhizomes and the lowest in the roots. Statistical analyses on TOC concentrations comparing the growing sites and the flood periods did not give any significant results for any part of papyrus. Lastly, the highest BSi concentrations were found in mature organs since silica is accumulated inside the plant throughout its life. BSi was not uniformly distributed among the different organs, possibly because of a passive transport of dissolved silica through the transpiration system and deposited in regions mostly affected by
water loss. The growing site does not seem to influence BSi concentrations in papyrus. However, BSi in rhizomes was twice as high during high flood periods than during flood recession.}},
author = {{Lodi, Giulia}},
language = {{eng}},
note = {{Student Paper}},
series = {{Dissertations in Geology at Lund University}},
title = {{A study of carbon, nitrogen, and biogenic silica concentrations in Cyperus papyrus, the sedge dominating the permanent swamp of the Okavango Delta, Botswana, Africa}},
year = {{2022}},
}