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Table 2 Comparison of Lotic Ecosystem Trophic Status Indices (LETSIs) and Trophic Classifications using Passive Diffusion Periphytometers in the Bosque River Watershed for all sites sampled during the indicated periods.

From: Measuring variability in trophic status in the Lake Waco/Bosque River Watershed

Date Site Number of Replicates Control Chl. a (ug cm-2)* N+P Chl. a (ug cm-2) LETSI Ecoregion 5 Trophic Classification#
July 17 – 30, 1997 NB-01 10 0.88 0.98 0.90 O
  NB-02 10 4.58 5.19 0.88 M
  NB-04 10 1.73 5.73 0.30 O
  NC 10 0.48 2.67 0.08 O
  MB 10 0.47 5.87 0.18 O
April 5 – 19, 1998 NC 10 0.71 1.21 0.59 O
  MB 10 0.56 0.91 0.61 O
May 11 – 26, 1998 NB-01 8 0.40 0.37 >1.0 O
  NB-02 9 9.02 8.07 >1.0 E
  NB-04 9 2.50 4.41 0.57 M
  NB-05 9 2.69 6.13 0.44 M
  HC 7 1.46 1.16 >1.0 O
  MB 8 0.83 6.35 0.13 O
July 30 – August 13, 1998 NB-04 8 0.49 4.55 0.11 O
  NB-05 9 0.99 2.15 0.46 O
October 10 – 24, 1998 NB-01 7 0.80 0.73 1.10 O
  NB-02 6 1.94 1.50 1.30 O
  NB-03 7 0.61 1.56 0.39 O
  1. *Measured as chlorophyll a production (μg cm-2) over 14 days on a control surface.
  2. # Trophic Classification defined by USEPA Eco-Region 5 (14), O = Oligotrophic, M = Mesotrophic, E = Eutrophic