In terms of ash-free dry mass, annual production amounted to 66.99 g AFDM
[m.sup.-2] [yr.sup.-1] (conversion factor 0.831 taken from Brey, 2001).
Breakdown rates (k) of each leaf species were calculated using the exponential decay model M = [M.sub.0][e.sup.-kt], where Mt is the remaining AFDM
at time t and [M.sub.0] is the initial mass.
Thus, the objective is (i) to present the general idea and formulation and (ii) to test the method in planar and spatial tensegrity structures of any type of complexity and to compare it with the DRM or the AFDM
The relationship between individual shell length and the AFDM
of the soft tissues was estimated by a linear regression analysis, following the equation: In W = ln a + b ln L, where W is the mean AFDM
(g); L is the individual length (mm); and a and b are the regression parameters.
To estimate the AFDM
to correct for the inorganic matter in the disks, they were dried and weighed according to the same process.
The samples were weighed and composited within category, then one subsample per category was ashed (550 C) to determine AFDM
We measured the concentration of suspended particulate organic matter (SPOM) by filtering 2-4 L of stream water at six locations through precombusted glass fiber filters (Whatman GFF) and determining AFDM
. Abundance of SPOM per unit area was calculated from SPOM concentration and average stream water depth.
Mean algal biomass for the reach (as chlorophyll a) increased from 14.75 [+ or -] 3.98 (SE) to 30.36 [+ or -] 2.09 mg/[m.sup.2] during this time, and sediment ash-free dry mass (AFDM
) increased from 85.07 [+ or -] 23.62 to 107.28 [+ or -] 14.46 g/[m.sup.2].
Other studies that have shown zoobenthos grazing to lower algal species diversity (Lowe and Hunter, 1988; Swamikannu and Hoagland, 1989; Underwood and Thomas, 1990), cell densities, chl a, and biomass (Hunter, 1980; Mulholland et al., 1983; Jacoby, 1985; Steinman et al., 1987; Lowe and Hunter, 1980; Osenberg, 1989; Underwood and Thomas, 1990; Bronmark et al., 1991; Tuchman and Stevenson, 1991; Hill et al., 1992), average cell biovolume (Bigger and Marvier, 1998), ash weight, and AFDM
(Steinman el al., 1987).
To compare biomass of fish and amphipods in common units, we estimated the aggregate ash-free dry mass (AFDM
) of grazers per unit of bottom (i.e., block) area (Table 2).
The filters were then dried (at 60 [degrees] C for 24 h), weighed to the nearest 0.01 mg, combusted (at 550 [degrees] C for 3 h), and reweighed to obtain periphyton ash-free dry mass (AFDM
We used grams of ash-free dry mass (AFDM
) as our energy proxy (e.g., Kingsley-Smith et al.