『Abstract
It is well known that termites enrich organic matter in their
nests and alter its properties, but their influence on phosphorus
forms is less clear. The aim of our study was to quantify and
systemize phosphorus forms in different nest parts outer wall,
inner wall, and central part) of termites of varying feeding guilds
and soils in seven dominant Brazilian ecosystems. Organic (Po)
and inorganic P (Pi) were analyzed after sequential extraction
of six labile and stable P fractions in samples from the Amazon
region (Terra firme, and Varzea（最初のaの頭に´）
and Igapo（oの頭に´） floodplains), the Pantanal,
the Atlantic rain forest (Mata Atlantica（最初のaの頭に^）),
the Cerrado and the Caatinga. In addition, selected alkaline extracts
were characterized by means of liquid-state 31P NMR
spectroscopy. The central part of termite nests contained between
275 and 1871 mg kg-1 total P, dominated by Pi in nests
of soil/wood interface-feeder termites, but with balanced Po and
Pi contents in nests of wood-feeding termites. All Po fractions,
and, in most nests, also labile Pi forms were enriched in termite
mounds in comparison to soils. The P enrichment was most pronounced
in nests of the Terra firme (enrichment factors for labile Pi
forms and for Po fractions were 1.7-36.5 and 1.1-16.8, respectively),
and the Igapo（oの頭に´） (labile Pi: 4.1-34.0;
Po: 1.1-25.7) where the total P content of the soil was the lowest
with 141 and 171 mg kg-1. Nests of wood-feeding termites
mainly accumulated highly labile resin-Pi (enrichment factor 10.5-36.5)
and partially the stable HClconc-Pi fractions,
apart from Po, which can be all attributed to the organic food
source and food digestion. The soil/wood interface-feeder termites
had more variations in their nests, but in general had higher
portions of P bonded to minerals. Hence, we conclude that (i)
termite activity results in a gross enrichment of labile P forms
in the nests, (ii) the P composition in termite nests reflects
the major feeding guild, and (iii) the degree of this P enrichment
is partly driven by the P stock in the soil.
Keywords: Sequential phosphorus extraction; 31P NMR;
Wood-feeding; Soil/wood interface-feeding; Isoptera; Brazil』
1. Introduction
2. Materials and methods
2.1. Samples
2.2. Chemical analyses
2.3. Statistical analyses
3. Results
3.1. Sequential P extraction
3.1.1. Soils
3.1.2. Wood
3.1.3. Termite nests
3.2. Carbon content and C/P ratio
3.3. 31P NMR spectra
4. Discussion
5. Conclusion
Acknowledgements
References
※リンの連続抽出法は、Tiessen and Moir（1993）を基にして一部修正したものを用いている。