SEASONAL CHANGES IN NUTRIENTS IN A TROPICAL SWAMP: NORTH SWAMP, LAKE NAIVASHA, KENYA
SEASONAL CHANGES IN NUTRIENTS IN A TROPICAL SWAMP: NORTH SWAMP, LAKE NAIVASHA, KENYA
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热带沼泽养分的季节性变化：肯尼亚奈瓦沙湖北部沼泽
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发表时间：
1979
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影响因子：
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通讯作者：
J. Gaudet
中科院分区：
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作者：
J. Gaudet
(1) 1975- 1976年，对肯尼亚奈瓦沙湖北端的纸莎草沼泽北沼泽进行了溶解（0-45-，um-过滤）营养物质的测定：NO2-N、NH3- N、有机N、全磷、P04 - P、S04 - s、Fe、Mn、02、pH、电导率和有机质。(2)偶尔分析颗粒物（0-45-100,um）的总C、N、S、Fe、Mn、阳离子、Cl、二氧化硅和有机物。(3)利用漂浮纸莎草垫下的沉积物捕集器估算了沼泽内的沉积速率。(4)所有溶解营养物（N、P、S、Fe和Mn）在沼泽垂直剖面上总体上表现出共同的规律，在沼泽表面最小，在沼泽底部最大。(5)沼泽中普遍的pH值、02和氧化还原电位表明，大部分铁在表面以铁-铁的形式存在，而铁-铁在底部占主导地位；P04 - P可能被吸附在沼泽表面的铁有机配合物上；锰是可溶的；S04 - S含量低，可能被吸附或以其他方式结合；H2S浓度极低；甲烷存在；氧气通常较低或缺乏。有机氮的年输出量远远大于河流的总输入量，这表明氮的数量是固定的。(6)最大不溶性物质（碎屑和颗粒物）超过27000 mg l-1。大部分营养物质都在这种有机沉积物中，这代表了沼泽每年养分输入的很大一部分。(7)纸莎草沼泽有效地从热带河流系统中提取溶解的营养物质，但这些营养物质后来以有机颗粒物的形式输出或被吸附到颗粒中，并通过通流进入湖泊。(8)纸莎草沼泽为湖泊-沼泽系统提供了相当数量的固定氮。
SUMMARY (1) North Swamp, a papyrus swamp at the north end of Lake Naivasha, Kenya, was assayed monthly during 1975-76 for dissolved (0-45-,um-filtered) nutrients: NO2-N, NH3- N, organic N, total P, P04 - P, S04 -S, Fe, Mn, 02, pH, conductivity and organic matter. (2) Particulate matter (0-45-100 ,um) was analysed occasionally for total C, N, S, Fe, Mn, cations, Cl, silica and organic matter. (3) Sediment traps under the floating papyrus mat were used to obtain an estimate of the rate of sedimentation inside the swamp. (4) All of the dissolved nutrients (N, P, S, Fe and Mn) generally showed a common pattern in vertical profiles through the swamp, with minimum values at the swamp surface and maximum values on the bottom. (5) The prevailing pH, 02 and redox potentials in the swamp indicate that at the surface much of the iron would be present as ferric-Fe, while ferrous-Fe predominates on the bottom; P04 - P may be adsorbed to Fe-organic complexes at the swamp surface; Mn would be in a soluble form; S04 - S is low and may be adsorbed or otherwise bound; H2S is in very low concentration; methane is present; and O2 is generally low or lacking. The annual output of organic N is much larger than the total input from the river, suggesting that nitrogen is fixed in appreciable quantities. (6) The maximum insoluble material (detritus and particulate matter) exceeds 27 000 mg l-1. Most of the nutrients were in this organic sediment, which represents a large portion of the annual nutrient input to the swamp. (7) It is concluded that papyrus swamps effectively extract dissolved nutrients from tropical river systems, but such nutrients are later exported as organic particulate matter or adsorbed to particles which are carried into the lake by through-flow. (8) It is also concluded that papyrus swamps contribute appreciable amounts of fixed nitrogen to lake-swamp systems.