CANAL 
leak 
60F _ it 
40-+ 
MARSH BAY 
PERCENT 
SHORE 
4of 
CENTER 
PERCENT 
80F 
100 A 6 . 
STATION 
Figure 2.—Sand, silt, and clay fractions of the sediments by station 
and zone. 
occurred at station 1, the farthest station from the 
open bay. Plant volume at station 4 (close to the bay) 
was similar to the volumes at stations 6 and 7 in the 
marsh. The highest volume of plant material occurred 
at station 8 where attached sea grasses were more 
abundant than at any other station. These grasses 
probably were effective in trapping detritus as it was 
flushed from the marsh by tidal action. Because almost 
no detritus was observed in the sediments from the 
open bay station, we think that most of the detritus in 
the altered area originated in the adjacent marsh. 
MILLILITERS 
Yy 7 | 7), 
_A_ m= lA | ZAE\Z. : 
1 4 6 7 8 1 
Figure 3.—Average volumes of organic matter (cord grass roots, sub- 
merged marine grasses, and organic detritus combined) by station and 
zone, March-October 1969. 
Seasonally, the volume of plant material changed 
little in the shore zone at stations 6, 7, and 8 where 
cord grass roots were abundant, but at the stations 
where detritus dominated the volume was much great- 
er during spring and early summer than in late summer 
and fall (Fig. 4). 
Dissolved oxygen values were consistently lower at 
station | in the deadend canal than at the other stations 
(Fig. 5); the observed values remained below 3 
m1/liter from June through mid-August. During this 
period, zero oxygen values were observed at station 1 
on three occasions (Corliss and Trent, 1971). 
Loa itr T T T T io Teen T Tea ol aa aaa T ~ | 
ah 77»SHORE STATION 
ae | ile 
O.5-F 
OF 
1OF 
5h 
(245}) 
5.0F 
40 
20 
nw- 
MILLILITERS 
10 
ob wr > —P | 
QE 4 1 1 4 1 4 4 = 1 4 1 JL 1 1 | 
25 8 226 20 3 17 | 15 29 l2 26 9 23 7 2i 
MAR APR. MAY JUN JUL AUG SEP Oct. 
Figure 4.—Average volume of organic matter by date, station, and 
zone. 
LILITERS PER LITER 
Figure 5.—Average dissolved oxygen by date for all six stations com- 
bined and for the stations having the highest and lowest average val- 
ues. 
RELATIVE ABUNDANCE 
During the study, 8,397 specimens of macroinver- 
tebrates belonging to four phyla were collected (Table 
1). The numbers of animals caught by station, family 
(phylum for nemerteans), date, and zone, and the vol- 
ume of the two samples by station and zone are shown 
in Appendix Tables 1 and 2. Polychaetes (Annelida) 
