Primary Productivity in Meromictic Big Soda Lake, Nevada
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Great Basin Naturalist Volume 38 Number 2 Article 4 6-30-1978 Primary productivity in meromictic Big Soda Lake, Nevada R. P. Axler University of California, Davis, California R. M. Gersberg University of California, Davis, California L. J. Paulson University of Nevada, Las Vegas, Nevada Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Axler, R. P.; Gersberg, R. M.; and Paulson, L. J. (1978) "Primary productivity in meromictic Big Soda Lake, Nevada," Great Basin Naturalist: Vol. 38 : No. 2 , Article 4. Available at: https://scholarsarchive.byu.edu/gbn/vol38/iss2/4 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. PRIMARY PRODUCTIVITY IN MEROMICTIC BIG SODA LAKE, NEVADA R. P. Axler', R. M. Gersberg', L. and J. Paulson^ Abstract.— In situ radiocarbon uptake measurements conducted at Big Soda Lake, Nevada, indicate that (i) bacterial photosynthesis comprises an important fraction (30 percent) of the lake's total primary production and (ii) bacterial chemosynthesis contributes significantly to organic particle production. The results of nutrient enrichment bioassay experiments support Hutchinson's prediction that availability of inorganic nitrogen, rather than phosphorus, limits primary production in the mixolimnion. Nutrient additions of NO3-N with Fe + '' most stimulated l'*C uptake. Big Soda Lake was described hydro- to investigate the possible nitrogen limita- logically as early as 1885 (Russell 1885) and tion suggested by Hutchinson. has received considerable limnological at- tention by virtue of its meromixis (Hutchin- Methods son 1937, 1957, Kimmel et al., in press). However, little biological data has been ac- Temperature, pH, and dissolved oxygen cumulated on the lake. Hutchinson, in 1933, were measured in situ with a calibrated found a thermally stratified mixolimnion Hydrolab water quality analyzer. Light pen- with an oxygen depleted hypolimnion, over- etration was measured with a Whitney lying an anoxic monimolimnion. He mea- LMD photometer. Total alkalinity was de- sured concentrations of a number of nutri- termined by potentiometric titration with ents and deduced that phosphorus was O.IN HCl. Chloride concentrations were de- much less likely to limit primary production termined by the argentometric method (Am. in the mixolimnion than inorganic combined Public Health Assoc. 1971). Total phos- nitrogen (Hutchinson 1937). Koenig et al. phorus, reactive iron, and nitrate were de- (1971) reported on the limnological status of termined by the methods of Strickland and the lake and noted a stratum of pink- Parsons (1968) as modified by Fujita (see colored water located in the deep hypolim- Goldman 1974). Ammonia was determined nion. Photosynthetic purple sulfur bacteria as per Solorzano (1969) as modified by Lid- were identified in this water (Rhodothece dicoat et al. (1975). In situ incubations of sp. and Thiothece sp.). However, primary water samples with ^d for determination of productivity measurements were not made. primary productivity and nutrient stimu- In a meromictic lake with high concen- lation followed the procedures developed trations of sulfide in the chemocline region and modified by Goldman (1963). Filtered and an anoxic (but photic) hypolimnion, samples were acid fumed (Wetzel 1965) to bacterial photosynthesis may comprise a sig- remove precipitated and adsorbed i-C. Solar nificant fraction of a lake's primary produc- insolation was recorded with a Belfort pyr- tion (Wetzel 1975, Cohen et al. 1977a, b). heliometer. Dissolved inorganic carbon We have utilized inorganic 14 C to esti- (DIG) available for photosynthesis was ap- mate the magnitude of algal and bacterial proximated from temperature, pH, and al- photosynthesis at Big Soda Lake and have kalinity data using the data of Saunders et conducted nutrient enrichment experiments al. (1962). This method probably over- 'Division of Environmental Studies, University of California, Davis, California 95616. 'Department of Biological Sciences, University of Nevada, Las Vegas, Nevada 89154. 187 188 Great Basin Naturalist Vol. 38, No. 2 estimates available DIG in alkaline Big 5 and 25 m. The zone below 17.5 m was Soda Lake samples (see Hutchinson 1957, oxygen deficient (<1 mg Og*^') and presum- Tailing 1973), and thereby results in some ably, could only support photosynthetic overestimation of primary productivity. growth by anaerobic bacteria.^ The areal productivity for this zone was calculated to Results and Discussion be 317 mg G*m-2'day-i. Similar calculations for the upper, aerobic zone yielded a value On 23 April 1977 the thermocline and of 717 mg G*m-2«day-i (phytoplankton pho- chemocline were located at about 5 m and tosynthesis). Therefore, the bacterial contri- 37.5 m, respectively (Fig. 1). The vertical bution to the total photosynthetic produc- extinction coefficient was 0.35 m-i and mea- tivity in the water column was 31 percent. surable light penetrated to 26 m. At all depths inorganic carbon uptake in The vertical distribution of primary pro- dark bottles represents a large percentage ductivity (Fig. 2) was bimodal with peaks at of that in light bottles, thus indicating sig- -I 12 16 20 24 28 32 Q CI"! 10 12 14 16 18 20 22 10 PH c PH 65 1977. Fig. 1. Depth profiles of temperature, pH, and chloride for Big Soda Lake, 23 April 'Recent evidence indicates that some species of Oscillatoria are able to photosynthesize anaerobically by using H2S as a source of electrons for pho- tosystem II (Cohen et al. 1975). June 1978 AXLER ET AL.: BiG SODA LaKE 189 nificant chemosynthetic activity. In the mix- from 55 to 9 jUgN-/-i (see Fig. 3). In the olimnion this is probably due to both ni- strictly anoxic monimolimnion, high dark trifying bacteria (which utiUze electrons uptake rates may be due to the presence of from NH4+ to reduce CO 2) and sulfur oxi- anaerobic sulfate reducing bacteria (e.g., dizing bacteria (which utilize electrons from Delsulfovibrio desulfuricans) which are fac- H2S to reduce CO2). Concentrations of sul- ultatively autotrophic and use molecular hy- fide (from Koenig et al. 1971) and ammonia drogen as an electron donor (Doelle 1975). (Fig. 3) in the region of the chemocline are Our data for total phosphorus, ammonia, 400 mg S*/-i and 4-34 mg N'/-i, respective- and iron (Fig. 3) are similar to those report- ly, and therefore, the gradual entrainment ed by Hutchinson (1937). A series of nutri- of monimolimnetic water (see Kimmel et ent enrichment experiments on epilimnetic al., in press) must introduce appreciable water collected on 24 April 1976 provided quantities of these nutrients into the mix- evidence to support Hutchinson's sugges- olimnion during the fall-winter overturn. tions concerning phosphorus and nitrogen Conditions in the deep hypolimnion are also limitation of primary productivity. Max- suitable for chemosynthetic denitrifying sul- imum stimulation of i^C uptake occurred in fur bacteria, such as Thiobacillus denitrifi- water samples enriched with both nitrate cans. The concentration of nitrate in the ox- and iron (Fig. 4). Phosphate additions, ei- ygen depleted hypolimnion does decline ther singly or together with nitrate or iron. mg C m'^hr' 8 10 12 10 20 30 40 50 60 70 80 H—J*—h- Light Bottle Uptoke. Dork Bottle Uptake Qa> 65 4 H h + -i h 2 4 6 8 10 12 mg O2 • I Fig 2. Depth profiles of dissolved oxygen and primary productivity, 23 April 1977 (1000-1400 hrs). Productiv- ity data represents the difference in uptake between light and dark sample bottles where each has been cor- rected for dark-uptake during the time between removal from the lake and filtration. 190 Great Basin Naturalist Vol. 38, No. 2 produced a small effect. Similarly, trace due to the role of iron in the assimilatory metal additions provided little stimulation reduction of nitrate by microorganisms. Af- imless added in concert with nitrate and ter reduction to nitrite via the enzyme nit- iron.^ rate reductase, further reduction to ammo- Primary production in many types of nium is catalyzed by nitrite reductase. Iron lakes has been shown to be limited by in- appears to be an integral component of organic nitrogen concentration and, in a both nitrite reductase and of ferredoxin, the number of hardwater calcareous lakes, by immediate electron donor (Morris 1975, available iron (Wetzel 1975). Goldman Healey 1973). (1972) reported that on water samples from The data we have accumulated on Big Lake Tahoe, Galifornia, nitrate and iron Soda Lake are of a preliminary nature and acting in concert produced a greater stimu- certainly insufficient to fully delineate the lation of primary productivity than either microbial processes occurring in the water one added singly. Such an effect may be column. However, they do indicate a very mg P or /xg Pel mg NH3-N I 10 20 30 40 50 60 4 8 12 16 20 24 28 32 36 40 I, I I ' I I i I I I I I I I I I .io- 5- OrvT" NO3-N 10- 15- 20- ^25- £ -- 30H Q. 35H !.._. ^ 40H 45- 50- 55- 60- 65 n 1 1 1 1 1 1 1 1 T" 8 16 24 32 40 48 56 64 72 80 fiq NO3-NI Fig. 3. Depth profiles of NO3-N and NH3-N (24 April 1977); total phosphoms, reactive iron, and NH3-N (24 April 1976). 'Unfortunately, the variance in our primary productivity data from April 1976 was generally too high to include in this report (presumably this was due to precipitation of carbonates during the sample filtrations with subsequent clogging of the filtration apparatus). However, the limnological condi- tion of the lake, as determined by vertical profiles of temperature, dissolved oxygen, light attenuation, alkalinity, pH, and chloride and ammonium con- centrations was virtually identical in 1976 to 1977.