The Littoral Zone
295
vegetation into the emergent vegetation, to a point where environmental conditions indicate
that the sediments are not continually water-saturated.
2. One team should collect plants along the transect for species composition, relative abundance,
and sediment characteristics (see Exercises 5 and 12).
a. In the laboratory, these plants should be identified as specifically as experience and time
permit. Use taxonomic keys of regional marsh and aquatic flora.
b. Plot graphically the vegetation distribution and relative abundance along the transect
gradient.
c. Plot the relative changes in the sediment characteristics along the gradient.
3. The second team should evaluate the foliage and root/rhizome biomass ofthe macrophytes in
four or more quadrats along the transect.
a. Using 0.25- to 0.50-ml quadrats, collect all above-ground biomass within the sampling
area.
b. Take at least five random cores ofthe root/rhizome materials within the quadrat extending
down through the root mass. Keep records of the sections of the root cores associated
with different dominant plant populations.
c. In the laboratory, determine the dry weight (l05°C) biomass of the foliage. On
representative subsamples, establish the ash by combustion at 550"C and calculate the
ash-free organic weight of the plant materials.
d. In white enamel or plastic pans, separate the viable roots and rhizomes from dead or
partially decayed materials and sediments. Determine the dry weight (105 q and the
ash-free dry weight (dry wt - ash wt) of all of the materials from the combustion of
representative samples at 550°C.
e. Calculate the dry weight and ash-free dry weight per m 2 of foliage, rooting material, and
the total combined biomass for dominant species of the quadrats. Repeat for other species
as time permits.
f. Calculate the estimated organic carbon of the materials from the ash-free dry weight data.
g. Plot the data graphically and compare the differences along the transect.
h. Assuming that the macrophytes are annual plants and that you sampled at maximum
seasonal biomass, calculate and compare the primary productivities of the dominant
species.
4. The third team should collect both qualitative and quantitative samples of algae attached
to plant surfaces and the sediments.
a. Using the artificial substrata, such as glass slides, that were placed about one month earlier
among the macrophytes and adjacent to littoral sediments, analyze for the following algal
biomass components:
1. Carefully collect the substrata so as to minimize loss upon retrieval. Place into
containers so that the surfaces do not rub against the substrata (e.g., wide-mouth
bottles with rubber stoppers containing cuts extending 5 mm into the narrow end; one
edge of a slide can be inserted into each slot of the stopper and then suspended into the
bottle).
II. In the laboratory, carefully remove all attached algae from a known area (e.g., cork
borer from a styrofoam substratum if these are used; or, using the edge of a clean slide,
scrape all microflora from one or both sides of the colonized slide) into a known
amount of filtered lake water.
111. Mix thoroughly and measure a known portion into a cell counting chamber (e.g.,
Palmer-Malony cell or sedimentation chamber-see Exercise 10).
IV. Enumerate and identify algae.
v. Filter a known volume of the homogeneous algae onto membrane filters and extract
chlorophyll a with 90% acetone as described in Exercise 10. Chlorophyll a and
phaeopigment concentrations can then be calculated as follows (Wetzel and Westlake,
1971 ):
flg ChI a per sample = 11.9 [2.43(ODb - ODa)] (v//)
where OD b = optical density at 665 nm in basic acetone, corrected for turbidity at
295
vegetation into the emergent vegetation, to a point where environmental conditions indicate
that the sediments are not continually water-saturated.
2. One team should collect plants along the transect for species composition, relative abundance,
and sediment characteristics (see Exercises 5 and 12).
a. In the laboratory, these plants should be identified as specifically as experience and time
permit. Use taxonomic keys of regional marsh and aquatic flora.
b. Plot graphically the vegetation distribution and relative abundance along the transect
gradient.
c. Plot the relative changes in the sediment characteristics along the gradient.
3. The second team should evaluate the foliage and root/rhizome biomass ofthe macrophytes in
four or more quadrats along the transect.
a. Using 0.25- to 0.50-ml quadrats, collect all above-ground biomass within the sampling
area.
b. Take at least five random cores ofthe root/rhizome materials within the quadrat extending
down through the root mass. Keep records of the sections of the root cores associated
with different dominant plant populations.
c. In the laboratory, determine the dry weight (l05°C) biomass of the foliage. On
representative subsamples, establish the ash by combustion at 550"C and calculate the
ash-free organic weight of the plant materials.
d. In white enamel or plastic pans, separate the viable roots and rhizomes from dead or
partially decayed materials and sediments. Determine the dry weight (105 q and the
ash-free dry weight (dry wt - ash wt) of all of the materials from the combustion of
representative samples at 550°C.
e. Calculate the dry weight and ash-free dry weight per m 2 of foliage, rooting material, and
the total combined biomass for dominant species of the quadrats. Repeat for other species
as time permits.
f. Calculate the estimated organic carbon of the materials from the ash-free dry weight data.
g. Plot the data graphically and compare the differences along the transect.
h. Assuming that the macrophytes are annual plants and that you sampled at maximum
seasonal biomass, calculate and compare the primary productivities of the dominant
species.
4. The third team should collect both qualitative and quantitative samples of algae attached
to plant surfaces and the sediments.
a. Using the artificial substrata, such as glass slides, that were placed about one month earlier
among the macrophytes and adjacent to littoral sediments, analyze for the following algal
biomass components:
1. Carefully collect the substrata so as to minimize loss upon retrieval. Place into
containers so that the surfaces do not rub against the substrata (e.g., wide-mouth
bottles with rubber stoppers containing cuts extending 5 mm into the narrow end; one
edge of a slide can be inserted into each slot of the stopper and then suspended into the
bottle).
II. In the laboratory, carefully remove all attached algae from a known area (e.g., cork
borer from a styrofoam substratum if these are used; or, using the edge of a clean slide,
scrape all microflora from one or both sides of the colonized slide) into a known
amount of filtered lake water.
111. Mix thoroughly and measure a known portion into a cell counting chamber (e.g.,
Palmer-Malony cell or sedimentation chamber-see Exercise 10).
IV. Enumerate and identify algae.
v. Filter a known volume of the homogeneous algae onto membrane filters and extract
chlorophyll a with 90% acetone as described in Exercise 10. Chlorophyll a and
phaeopigment concentrations can then be calculated as follows (Wetzel and Westlake,
1971 ):
flg ChI a per sample = 11.9 [2.43(ODb - ODa)] (v//)
where OD b = optical density at 665 nm in basic acetone, corrected for turbidity at