MERC ER01-14
12
NTL Live Organisms ≥50 µm
Samples from the 35 µm mesh nets.
Sample ID
Ave (#/m
3
)
SD
Challenge
55,235
2,066
Treated
22,412
1,612
Zooplankton Taxa and Observations
Minimum dimensions measured.
Challenge (pre-filter)
1. Eleven (11) taxa or general categories were present in the challenge samples: copepod nauplii,
Calanoida, Cyclopoida, Harpacticoida, Rotifera, Polychaeta, barnacle nauplii, diatoms, eggs,
chaetognaths, and bivalves.
2. Copepod nauplii were the most abundant taxa.
Treated (post-filter)
1. Five (5) taxa or general categories, copepod nauplii, Polychaeta, Rotifera, eggs, and barnacle
nauplii were present in the treated samples.
2. Six (6) taxa or general categories listed in the challenge sample were
absent
in the treated
samples: Calanoida, Cyclopoida, Harpacticoida (all three are adult-stage copepods), diatoms,
chaetognaths, and bivalves.
3. Fifty percent (50%) fewer copepod nauplii were found in the treated samples than in the
challenge samples.
4. Copepod nauplii measured mainly in the 50-60 µm size class, with one measuring 85 µm.
5. Polychaetes, rotifers and eggs were similar in quantities in both challenge and treated samples.
6. Polychaetes measured mainly in the 50-80 µm size class, with two measuring 90 µm.
NTL Live Organisms
≥
10 - <50 µm
Samples from the time-integrated chambers.
Sample ID
Ave (#/ml)
SD
Challenge
1,124
107
Treated
459
85
Phytoplankton Observations
Challenge and Treated
1. Majority of the species observed are diatoms, including
Skeletonema
and
Chaetoceros
. Most
(at least three species) are short chain formers (8 cells or less). A few larger discoid and
pennate diatom forms were noted.
Treated (post-filter)
1. Numbers were noticeably reduced in the treated samples.
2. Some larger diatoms and chains over 20 µm were observed.
