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Sự bẫy chất hữu cơ trong các vùng cây cỏ ở các kênh của Đồng bằng Okavango: một vấn đề về chất lượng
Tóm tắt
Vai trò của thực vật thủy sinh trong dòng chảy như những kỹ sư hệ sinh thái trong việc phân bố chất hữu cơ đã được nghiên cứu tại Đồng bằng Okavango, một trong những vùng đầm lầy oligotrophic lớn nhất thế giới. Các lòng kênh của Okavango được phủ tới 50% bằng các vùng cây cỏ ngập nước. Bằng cách tích lũy và tập trung chất hữu cơ trong trầm tích dưới các vùng cây cỏ, thực vật ngập nước có khả năng ngăn chặn tình trạng thiếu dinh dưỡng tại địa phương. Lượng N gấp 21 lần, C gấp 18 lần, P gấp 13 lần và Si gấp 6 lần có thể được tìm thấy trong các trầm tích có thực vật so với các trầm tích không có thực vật. Việc tích lũy dinh dưỡng riêng biệt liên quan đến mức độ khan hiếm tương đối của nó trong nước phía trên. Có sự suy giảm N hòa tan so với P, trong khi Si lại tương đối dồi dào. Nước ở Đồng bằng Okavango thường được đặc trưng là oligotrophic dựa trên thành phần loài thực vật (ví dụ: sự hiện diện của các loài thực vật ăn thịt và sự vắng mặt của các loài thực vật nổi), tỷ lệ N:P thấp của thực vật, và các nồng độ dinh dưỡng và nguyên tố thấp. Quy trình khoáng hóa tại địa phương và chu trình dinh dưỡng tăng cường trong các trầm tích được giả thuyết là rất quan trọng cho sự tồn tại của thực vật ngập nước vì nó cung cấp nguồn dinh dưỡng thiết yếu mà các thực vật không thể có được đủ từ nước nghèo dinh dưỡng. Bằng cách kỹ sư hệ sinh thái như vậy, thực vật ven kênh cũng làm chậm mất đi các nguyên tố và dinh dưỡng tới dòng nước ngầm trên đảo, góp phần vào một trong những quy trình chính thúc đẩy năng suất cao của Đồng bằng Okavango, làm cho nó trở nên độc đáo giữa các vùng tương tự.
Từ khóa
#thực vật thủy sinh #chất hữu cơ #đồng bằng Okavango #oligotrophic #chu trình dinh dưỡng #kỹ sư hệ sinh thái.Tài liệu tham khảo
Adamec L (1997) Mineral nutrition of carnivorous plants: a review. Bot Rev 63:273–299
Alfredsson H, Hugelius G, Clymans W, Stadmark J, Kuhry P, Conley DJ (2015) Amorphous silica pools in permafrost soils of the Central Canadian Arctic and the potential impact of climate change. Biogeochemistry 1–19
Appleton CC, Curtis BA, Alonso LE, Kipping J (2003) Chap. 4: Freshwater Invertebrates of the Okavango Delta, Botswana. In: Alonso LE, Nordin L-A (eds.) A rapid biological assessment of the aquatic ecosystems of the Okavango Delta, Botswana: high Water Survey Conservation. International Center for Applied Biodiversity Science, Washington, DC, pp 58–68
Bal K, Brion N, Woulé-Ebongué V, Schoelynck J, Jooste A, Barrón C, Dehairs F, Meire P, Bouma T (2013) Influence of hydraulics on the uptake of ammonium in two freshwater aquatic plants. Freshw Biol 58:2452–2463
Battin TJ, Kaplan LA, Findlay S, Hopkinson CS, Marti E, Packman AI, Newbold JD, Sabater, F (2008) Biophysical controls on organic carbon fluxes in fluvial networks. Nat Geosci 1: 95–100
Berg B, McClaugherty C (2003) Plant litter: decomposition, humus formation, carbon sequestration. Springer, Berlin
Bouma TJ, van Duren LA, Temmerman S, Claverie T, Blanco-Garcia A, Ysebaert T, Herman PMJ (2007) Spatial flow and sedimentation patterns within patches of epibenthic structures: combining field, flume and modelling experiments. Cont Shelf Res 27:1020–1045
Caraco N, Cole J, Findlay S, Wigand C (2006) Vascular plants as engineers of oxygen in aquatic systems. Bioscience 56:219–225
Cotton JA, Wharton G, Bass JAB, Heppell CM, Wotton RS (2006) The effects of seasonal changes to in-stream vegetation cover on patterns of flow and accumulation of sediment. Geomorphology 77:320–334
Cronberg G, Gieske A, Martins E, Stenstrom I (1996) Hydrobiological studies of the Okavango Delta and Kwando–Linyanti–Chobe River, Botswana. Surface water quality analysis. Botsw Notes Rec 27:151–226
Dallas HF, Mosepele B (2006) A preliminary survey and analysis of the spatial distribution of aquatic invertebrates in the Okavango Delta, Botswana. Afr J Aquat Sci 32:1–11
DeMaster DJ (1981) The supply and accumulation of silica in the marine-environment. Geochim et Cosmochim Acta 45:1715–1732
Dobson M, Magana A, Mathooko JM, Ndegwa FK (2002) Detritivores in Kenyan highland streams: more evidence for the paucity of shredders in the tropics? Freshw Biol 47:909–919
Ellery WN, Tacheba B (2003) Chap. 5: Floristic diversity of the Okavango Delta, Botswana. In: Alonso LE, Nordin L-A (eds) A Rapid Biological Assessment of the Aquatic Ecosystems of the Okavango Delta, Botswana: High Water Survey Conservation International Center for Applied Biodiversity Science Washington, DC p69–96
Emsens W-J, Schoelynck J, Grootjans AP, Struyf E, Van Diggelen R (2016) Eutrophication alters Si cycling and litter decomposition in wetlands. Biogeochemistry 130:1–11
Fisher SG, Grimm NB, Marti E, Holmes RM, Jones JB (1998) Material spiraling in stream corridors: A telescoping ecosystem model. Ecosystems 1:19–34
Frings PJ, De La Rocha C, Struyf E, van Pelt D, Schoelynck J, Hudson MM, Gondwe MJ, Wolski P, Mosimane K, Gray W, Schaller J, Conley DJ (2014) Tracing silicon cycling in the Okavango Delta, a sub-tropical flood-pulse wetland using silicon isotopes. Geochim et Cosmochim Acta 142 :132–148
Gessner MO, Chauvet E, Dobson M (1999) A perspective on leaf litter breakdown in streams. Oikos 85:377–384
Grasshoff K, Ehrhardt M, Kremling K (1983) Methods of seawater analysis. Wiley-VCH, Germany
Green JC (2005) Modelling flow resistance in vegetated streams: review and development of new theory. Hydrol Processes 19:1245–1259
Gumbricht T, McCarthy J, McCarthy TS (2004) Channels, wetlands and islands in the Okavango Delta, Botswana, and their relation to hydrological and sedimentological processes. Earth Surf Process Landf 29:15–29
Gurnell AM (2014) Plants as river system engineers. Earth Surf Process Landf 39:4–25
Hagerthey SE, Cole JJ, Kilbane D (2010) Aquatic metabolism in the Everglades: Dominance of water column heterotrophy. Limnol Oceanogr 55:653–666
Heiri O, Lotter AF, Lemcke G (2001) Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results. J Paleolimnol 25:101–110
Hicks DM, Duncan MJ, Lane ST, Tal M, Westway R (2008) Contemporary morphological change in braided gravel–bed river: new developments from field and laboratory studies, with particular reference to the influence of riparian vegetation. In: Habersack H, Piégay H, Rinaldi M (eds.) Gravel-bed Rivers VI: from process understanding to river restoration (developments in earth surface processes). Elsevier, Amsterdam, pp 557–584
Horvath TG (2004) Retention of particulate matter by macrophytes in a first-order stream. Aquat Bot 78:27–36
Humphries M, McCarthy T, Cooper G, Stewart RA, Stewart RD (2014) The role of airborne dust in the growth of tree islands in the Okavango Delta, Botswana. Geomorphology 206:307–317
Irons JG, Oswood MW, Stout RJ, Pringle CM (1994) Latitudinal patterns in leaf-litter breakdown—is temperature really important? Freshw Biol 32:401–411
Janauer GA, Schmidt-Mumm U, Reckendorfer W (2013) Ecohydraulic and aquatic macrophytes: assessing the relationship in river floodplains. In: Maddock I, Harby A, Kemp P, Wood P (eds.) Ecohydraulics: an integrated approach. Wiley, Chichester, pp 245–259
Jones CG, Lawton JH, Shachak M (1994) Organisms as ecosystem engineers. Oikos 69:373–386
Kleeberg A, Kohler J, Sukhodolova T, Sukhodolov A (2010) Effects of aquatic macrophytes on organic matter deposition, resuspension and phosphorus entrainment in a lowland river. Freshw Biol 55:326–345
Koerselman W, Meuleman AFM (1996) The vegetation N:P ratio: a new tool to detect the nature of nutrient limitation. J Appl Ecol 33:1441–1450
Krah M, McCarthy TS, Huntsman-Mapila P, Wolski P, Annegarn H, Sethebe K (2006) Nutrient budget in the seasonal wetland of the Okavango Delta, Botswana. Wetlands Ecol Manage 14:253–267
Larsen LG, Harvey JW (2010) How vegetation and sediment transport feedbacks drive landscape change in the Everglades and wetlands worldwide. Am Nat 176(3):E66–E79
Mackay AW, Davidson T, Wolski P, Mazebedi R, Masamba WRL, Huntsman-Mapila P, Todd M (2011) Spatial and seasonal variability in surface water chemistry in the Okavango Delta, Botswana: a multivariate approach. Wetlands 31:815–829
Madsen TV, Cedergreen N (2002) Sources of nutrients to rooted submerged macrophytes growing in a nutrient-rich stream. Freshw Biol 47:283–291
Masese FO, Kitaka N, Kipkemboi J, Gettel GM, Irvine K, McClain ME (2014) Macroinvertebrate functional feeding groups in Kenyan highland streams: evidence for a diverse shredder guild. Freshw Sci 33:435–450
McCarthy TS, Stanistreet IG, Cairncross B (1991) The sedimentary dynamics of active fluvial channels on the Okavango fan, Botswana. Sedimentology 38:471–487
McCarthy TS, Ellery WN, Dangerfield JM (1998) The role of biota in the initiation and growth of islands on the floodplain of the Okavango alluvial fan, Botswana. Earth Surf Process Landf 23:291–316
McCarthy JM, Gumbricht T, McCarthy T, Frost P, Wessels K, Seidel F (2003) Flooding patterns of the Okavango wetland in Botswana between 1972 and 2000. Ambio 32:453–457
McCarthy TS, Humphries MS, Mahomed I, Le Roux P, Verhagen BT (2012) Island forming processes in the Okavango Delta, Botswana. Geomorphology 179:249–257
Mladenov N, McKnight DM, Wolski P, Ramberg L (2005) Effects of annual flooding on dissolved organic carbon dynamics within a pristine wetland, the Okavango Delta, Botswana. Wetlands 25:622–638
Mosimane K, Struyf E, Gondwe MJ, Frings P, van Pelt D, Wolski P, Schoelynck J, Schaller J, Conley DJ, Murray-Hudson M (2017) Variability in chemistry of surface and soil waters of an evapotranspiration-dominated flood-pulsed wetland: solute processing in the Okavango Delta, Botswana. Water SA 43(1):104–115
R Core Team (2013) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org
Ramberg L, Wolski P (2008) Growing islands and sinking solutes: processes maintaining the endorheic Okavango Delta as a freshwater system. Plant Ecol 196:215–231
Sand-Jensen K (1998) Influence of submerged macrophytes on sediment composition and near-bed flow in lowland streams. Freshw Biol 39:663–679
Schaller J, Struyf E (2013) Silicon controls microbial decay and nutrient release of grass litter during aquatic decomposition. Hydrobiologia 709:201–212
Schaller J, Schoelynck J, Struyf E, Meire P (2016) Silicon affects nutrient content and ratios of wetland plants. Silicon 8:479–485
Schoelynck J, Struyf E (2016) Silicon in aquatic vegetation. Funct Ecol 30:1323–1330
Schoelynck J, De Groote T, Bal K, Vandenbruwaene W, Meire P, Temmerman S (2012) Self-organised patchiness and scale-dependent bio-geomorphic feedbacks in aquatic river vegetation. Ecography 35:760–768
Schoelynck J, Meire D, Bal K, Buis K, Troch P, Bouma T, Meire P, Temmerman S (2013) Submerged macrophytes avoiding a negative feedback in reaction to hydrodynamic stress. Limnologica 43:371–380
Schoelynck J, Bal K, Verschoren V, Penning E, Struyf E, Bouma T, Meire D, Meire P, Temmerman S (2014) Different morphology of Nuphar lutea in two contrasting aquatic environments and its effect on ecosystem engineering. Earth Surf Process Landf 39:2100–2108
Struyf E, Conley DJ (2012) Emerging understanding of the ecosystem silica filter. Biogeochemistry 107:9–18
Struyf E, Mosimane K, Van Pelt D, Murray-Hudson M, Meire P, Frings P, Wolski P, Schaller J, Gondwe MJ, Schoelynck J, Conley DJ (2015) The role of vegetation in the Okavango Delta silica sink. Wetlands 5:171–181
Tal M, Paola C (2007) Dynamic single-thread channels maintained by the interaction of flow and vegetation. Geology 35:347–350
Taylor BR, Parkinson D, Parsons WFJ (1989) Nitrogen and lignin content as predictors of litter decay-rates—a microcosm test. Ecology 70:97–104
Temmerman S, Bouma TJ, Van de Koppel J, Van der Wal DD, De Vries MB, Herman PMJ (2007) Vegetation causes channel erosion in a tidal landscape. Geology 35:631–634
Thompson K (1976) The primary productivity of African Wetlands, with particular reference to the Okavango Delta, Paper presented at the Symposium on the Okavango Delta and its future utilization, Botswana Society, National Museum, Gaborone, Botswana
van Wesenbeeck BK, van de Koppel J, Herman PMJ, Bouma TJ (2008) Does scale-dependent feedback explain spatial complexity in salt-marsh ecosystems? Oikos 117:152–159
Vannote RL, Minshall GW, Cummins KW, Sedell JR, Cushing CE (1980) River Continuum Concept. Can J Fish Aquatic Sci 37:130–137
Walinga I, Van Vark W, Houba VJG, Van Der Lee JJ (1989) Plant analysis procedures. Soil and Plant Analysis, Part 7. Wageningen, NL
Webster JR, Benfield EF (1986) Vascular plant breakdown in fresh-water ecosystems. Annu Rev Ecol Syst 17:567–594
Wetzel PR, van der Valk AG, Newman S, Gawlik DE, Gann TT, Coronado-Molina CA, Childers DL, Sklar FH (2005) Maintaining tree islands in the Florida Everglades: nutrient redistribution is the key. Front Ecol Environ 3(7):370–376
Wolski P, Savenije HHG, Murray-Hudson M, Gumbricht T (2006) Modelling of the flooding in the Okavango Delta, Botswana, using a hybrid reservoir-GIS model. J Hydrol 331:58–72