KBS011: Equations for Soil Microbial Biovolume and Carbon Calculation

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Abstract

The equations for calculation of soil microbial biovolume and carbon are specified.

Protocol

Epifluorescence Microscopy: Equations for Soil Microbial Biovolume and Carbon Calculation


VARIATE:


DEFINITION AND EQUATION:


s:


Mass of soil per image(µg)

Mass of soil per image

where
x = 512 * 0.089(µm),
y = 768 * 0.089 (µm) for bacterial images;
x = 512 * 1.0 (µm),
y = 768 * 1.0 (µm) for fungal hyphal images;
%H2O = water content of soil sample.


bv:


Volume of each bacterial cell (µm3 )

Volume of bacteria

d = small diameter of cell


l= long diameter of cell


The volume (bv) of each bacteria is calculated from measurements of the large,
l, and small,
d, diameters of each cell by assuming that the cells are
prolate spheroids.


BAC_NUM:


Total bacteria (cells g-1soil)

BAC_NUM = count per image / S


BAC_VOL:


Bacterial biovolume (µm3g-1 soil)

BAC_VOL =Equation for bacterial volume


BAC_C:


Bacterial biomass C (µgC g-1soil)

BAC_C = BAC_VOL * 0.2

The factor 0.2 used to convert
bacterial biovolume to carbon © is thought to be the
best available based on a range of estimates available in
the literature.


hv:


Volume of each hyphal fragment (µm3)

Equation for hyphal volume

d = hyphal diameter


l = hyphal length


Hyphal volume for each fragment is calculated assuming
the hyphae are simple cylinders of length
l and diameter
d.


HYP_LEN:


Total fungal hyphal length (m g-1
soil)

HYP_LEN =Equation for hyphal length *10-6

l = hyphal length


HYP_DIAM:


Mean fungal hyphal diameter (µm)


HYP_VOL:


Fungal hyphal biovolume (µm3 g-1 soil)

HYP_VOL = Equation for hyphal volume


HYP_C:


Fungal hyphal biomass C (µgC g-1 soil)

HYP_C = HYP_VOL * 0.15

The factor 0.15 used to convert fungal
biovolumes to carbon © is thought to be the best
available based on a range of estimates available in the
literature.


DMC_C:


Total microscopic biomass C (µgC g-1 soil)

DMC_C = BAC_C + HYP_C

Author:

Datatables