Short-Term Photochemical and Biological Unreactivity of Macrophyte-Derived Dissolved Organic Matter in a Subtropical Shallow Lake

Table 1

Limnological and biological characterization of the water in the initial conditions of the experiment.

𝑍mean

AT^1

pH

TS

Alk

TN

TP

DOC

Abs430

GR^2

LMW

HMW

Abs250 : 365

BP

BR

BGE

2.0

17.6; (3.4)

7.62; (0.07)

108; (2.6)

797; (72)

637; (326)

16.1; (2.6)

10.9; (1.5)

0.04; (0.001)

201.8; (70)

0.07; (0.006)

0.09; (0.004)

0.80; (0.060)

0.235; (0.042)

4.336; (4.255)

0.146; (0.183)

1Mean air temperature for the 5 days of incubation.
²Mean daily flux of GR during incubation (n = 5); 1 W = 1 J s⁻¹. For all other variables, n = 3.
³Figures in parentheses are ±standard deviations.
⁴𝑍_mean: mean depth (m); AT: air temperature (°C); TS: total solids (mg L⁻¹); Alk: alkalinity (μEq L⁻¹); TN: total nitrogen (μg L⁻¹); TP: total phosphorus (μg L⁻¹); DOC: dissolved organic carbon (mg L⁻¹); Abs430: absorbance at 430 nm; GR: global radiation flux (W m⁻²); LMW: low-molecular-weight substances (absorbance at 250 nm); HMW: high-molecular-weight substances (absorbance at 365 nm); Abs250 : 365: (ratio of absorbances at 250 and 365 nm); BP: bacterial production (µg C L h⁻¹); BR: bacterial respiration (µg C L h⁻¹); BGE: bacterial growth efficiency.