PE EIE[R-Rg RESEARCH ON - HJ Andrews Experimental Forest

photosynthetic activity with respect to sea -
son, time of day, and depth, one might expec t
measurements to approach the maximu m
values that these variables would attain in
situ .
Reviews and key papers concerning variou s
aspects of the carbon cycle in the aquati c
realm include the following : zooplankto n
physiology (Corner and Coney 1968), primary
productivity (Ryther 1963, Steemann -
Nielsen 1963, and Strickland 1965), dissolve d
organic carbon (Provisoli 1963, Duursma
1965 ), detritus (Parsons 1963), bacteria
(Wood 1965, Brock 1966, and Lighthart
1969), and food chains (Riley 1963) . Also
some detailed methods are given in IBP Hand -
books 12 and 17, Primary Production i n
Aquatic Environments and Secondary Productivity
in Fresh Waters (Edmondson and
Winberg 1971) .
To this point, the discussion has been wit h
what might be called a primary system, the
components in the carbon web . This system is
controlled by another [or] secondary system ,
the physical and chemical environment . Som e
of the environmental factors operating on th e
primary system are listed in table 1 .
Because factors in the secondary syste m
regulate changes in the primary system, meas -
urements of the primary system may allow u s
to interpret the major controlling variables o f
the water bodies .
Table 1 .-Some environmental factors operating
on the aquatic carbon we b
Temperature
Light intensity, quality, and duration
pH
Trace elements
External inputs of organic matter ,
i.e ., nutrients, antibiotics, and
growth factors
Phosphorou s
Silica
Calciu m
Environmental confine s
Water circulation
Purpose
It is proposed that, when possible, one station
will be occupied on each of four lakes i n
the Cedar River watershed : Lake Washington ,
Lake Sammamish, Lake Chester Morse, an d
Lake Findley, during the four seasons of th e
year. While occupied, the flux and pool size s
of six carbon compartments will be measured
in the epi- and hypo-limnions . The purpose of
this investigation is to determine whether the
four lakes are distinguishable in terms of the
fluxes and pool sizes of the six carbon compartments
with the methods outlined below .
Methods
Carbon pools in each compartment will b e
made by : (1) estimating the protoplasmic
carbon pool from cell volume, and (2) from
infrared spectrophotometric measurement o f
oxidized cellular carbon . Carbon flux between
compartment pools will be estimated by
following the transfer of carbon-14 added to
specific compartments .
Carbon Pool Analysi s
It is necessary to determine the "cold "
carbon pool size, both to evaluate its standin g
stock, and in calculating specific activities .
Inorganic carbon in the lake water will b e
measured either by determining the tota l
alkalinity (American Public Health Association
1971), pH, and temperature, and the n
consulting the appropriate tables (Saunders e t
al. 1962) for total available inorganic carbon ,
or by direct measurement using an infrared
CO 2 analyzer (Menzel and Vaccaro 1964) .
The dissolved organic carbon in the water
samples will be determined on the filtrate of a
O.22µ Millipore filtered sample of the test
water using the method of Menzel and Vaccaro
(1964) . Carbonates will be driven off th e
filtrate prior to analysis by sparging th e
phosphoric-acid-acidified filtrate with nitrogen
gas .
The carbon content of the planktonic algae
will be made either from dry weight estimation
by calculation from cell counts an d
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