MAYAN URBANISM - IMPACT ON A TROPICAL KARST ENVIRONMENT
MAYAN URBANISM - IMPACT ON A TROPICAL KARST ENVIRONMENT
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DOI：
10.1126/science.206.4416.298
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发表时间：
1979-01-01
期刊：
影响因子：
56.9
通讯作者：
FLANNERY, MS
中科院分区：
文献类型：
--
作者：
DEEVEY, ES;RICE, DS;FLANNERY, MS
从公元前第一个千年到公元9世纪的经典玛雅崩溃，在双子湖(雅克哈-萨克纳布)盆地，非城市人口呈指数级增长，每408年翻一番。雅克哈-萨克纳布盆地包含雅克哈的经典城市中心。花粉数据显示，在古典时代早期，森林基本上已经消失。城市建设放大了雅夏次盆地急剧加速的坡面冲刷和胶结作用，将营养物质加上钙质、粉质粘土转移到两个湖泊。除城市淤泥外，以湖泊沉积物形式出现的堆积物的总磷平均浓度与盆地土壤接近。根据这一事实，从土壤磷的丰度和分布，以及从玛雅之后的持续流入(每年每平方米80-86毫克磷)(没有其他明显来源)，我们得出结论，滨海土壤是人为土壤，湖泊长期磷负荷的机制是土壤的质量运输。磷的人均输出量与生理产量相匹配，每年人均磷约为0.5公斤。较小的表观输出量反映了城市淤泥的非磷组成；较大的社会输出量，表示来自森林砍伐、食物垃圾和殡葬处理的过量磷，是可能的，但不能从我们的数据中进行评估。富营养化并不明显，即使在受影响较小的湖泊中，也可能受到悬浮的玛雅淤泥的阻碍。环境菌株是加速农业工程需求和将营养物质隔离在冰川中的产物，发展得太慢，无法起到伺服机制的作用，抑制了人口增长，至少在古典时代晚期是这样。
From the first millennium B.C. through the 9th-century A.D. Classic Maya collapse, nonurban populations grew exponentially, doubling every 408 years, in the twin-lake (Yaxha-Sacnab) basin that contained the Classic urban center of Yaxha. Pollen data show that forests were essentially cleared by Early Classic time. Sharply accelerated slopewash and colluviation, amplified in the Yaxha subbasin by urban construction, transferred nutrients plus calcareous, silty clay to both lakes. Except for the urban silt, colluvium appearing as lake sediments has a mean total phosphorus concentration close to that of basin soils. From this fact, from abundance and distribution of soil phosphorus, and from continuing post-Maya influxes (80 to 86 milligrams of phosphorus per square meter each year), which have no other apparent source, we conclude that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil. Per capita deliveries of phosphorus match physiological outputs, approximately 0.5 kilogram of phosphorus per capita per year. Smaller apparent deliveries reflect the nonphosphatic composition of urban silt; larger societal outputs, expressing excess phosphorus from deforestation and from food waste and mortuary disposal, are probable but cannot be evaluated from our data. Eutrophication is not demonstrable and was probably impeded, even in less-impacted lakes, by suspended Maya silt. Environmental strain, the product of accelerating agroengineering demand and sequestering of nutrients in colluvium, developed too slowly to act as a servomechanism, damping population growth, at least until Late Classic time.