New and recycled primary production in an oligotrophic lake: Insights for summer phosphorus dynamics

Caraco, Nina F.; Cole, Jonathan J.; Likens, Gene E.

doi:10.4319/lo.1992.37.3.0590

Cited by 80 publications

(56 citation statements)

References 20 publications

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“…Thus, phytoplankton production would consume an average of 29-44% of usual DIN concentrations and 3-5% of SRP per hour (Table 1). Though crude, these calculations show that mineralization or direct uptake of organic N and P is probably vital for supporting the nutrient demands of littoral phytoplankton, microbes, and periphyton (see also Caraco et al 1992). There is growing recognition that rapid recycling of organic nutrients is important in temperate lakes (Hudson et al 2000;Mitchell and Baldwin 2005), and our calculations support the hypothesis that nutrient recycling is critical in meromictic tropical lakes in order to sustain high productivity despite low inorganic nutrient concentrations (Kilham and Kilham 1990).…”

Section: Discussionsupporting

confidence: 75%

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

2006

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We studied the effects of nutrient availability and grazers on periphyton in the littoral zone of Lake Tanganyika. Using a combination of dissolved nutrient ratios, nutrient diffusing substrates, and benthic productivity responses to nutrient supplementation, we evaluated whether nitrogen (N) or phosphorus (P) limited periphyton productivity near Kigoma, Tanzania, during the dry seasons of 2001 and 2002. The relative effects of grazers and nutrients on periphyton were quantified by manipulating grazer access to nutrient diffusing substrates. We found very low ambient concentrations of inorganic N and soluble reactive P, but generally higher concentrations of dissolved organic nutrients. Nutrient diffusing substrates indicated a shift from P limitation in 2001 to co-limitation by N and P in 2002, probably as a consequence of unusual coastal upwelling in 2002. Productivity responses of natural epilithic algae to nutrient supplementation also indicated N-P co-limitation in 2002. However, fish and other large grazers had much stronger effects on periphyton than nutrients. Grazers strongly suppressed periphyton biomass, but had weaker negative effects on area-specific gross primary productivity as a result of large increases in biomass-specific gross primary productivity. We conclude that littoral nutrient availability influenced periphyton productivity, but that top-down control predominated.

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Section: Discussionsupporting

confidence: 75%

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

2006

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“…Despite the importance of internal nutrient loading by gizzard shad (this study), nutrient transport by other fish species (Lamarra 1975;Bray et al 1981;Meyer and Schultz 1985;Kline et al 1990;Bilby et al 1996), and nutrient recycling by planktivorous fish Kraft 1992Kraft , 1993Schindler et al 1993;Vanni et al 1997), many lake nutrient budgets have either downplayed or ignored the role of fish (Caraco et al 1988(Caraco et al , 1992Hama et al 1990;James and Barko 1993). Although fish may not always regulate major nutrient fluxes in lakes, inclusion of their roles may help to balance nutrient budgets and depict more accurately the cycling of materials within these systems.…”

Section: Discussionmentioning

confidence: 99%

“…Excretion by gizzard shad may represent a steady, consistent supply of nutrients to phytoplankton (Kitchell et al 1975;Vanni 1996) that may allow maintenance of high primary productivity even when external inputs of nutrients are greatly reduced (Caraco et al 1992;Vanni 1996). Although the importance of internal nutrient cycling to the maintenance of primary productivity is well recognized (Dugdale and Goering 1967;Pace et al 1987;Hama et al 1990;Caraco et al 1992), the contribution of fishes (especially detritivorous fishes) to this process is not well understood.…”

mentioning

confidence: 99%

Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem

Schaus

Vanni

Wissing

et al. 1997

Limnology & Oceanography

177

206

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The detritivorous fish, gizzard shad (Dorosoma cepedianum), provides nutrients to phytoplankton in reservoirs by ingesting organic detritus associated with sediments and excreting substantial quantities of nutrients such as N and P in soluble forms that are highly available to phytoplankton, We estimated nutrient excretion by gizzard shad in a eutrophic reservoir (Acton Lake, Ohio) during April-October 1994 by measuring N and P excretion of fieldcaught fish (n = 135). Excretion rates were then extrapolated to nutrient release by the gizzard shad population using quadrat rotenone biomass estimates, electrofishing surveys, and historic seasonal trends. N and P excretion were positively correlated with fish wet mass and temperature, but mass-specific excretion declined with increasing fish mass. Lakewidc gizzard shad biomass in July 1994 was 417 kg ha -I, Our estimates of nutrient excretion by the gizzard shad population ranged from 0.487 to 0.769 pmol NH,-N liter-' d-l and 0.022 to 0.057 pmol soluble reactive phosphorus liter -I d .I, with the highest excretion occurring during mid-summer through early fall. The low N : P ratio at which gizzard shad excrete [mean molar N : P = 16.75 (kO.89 SE)] may alter phytoplankton community composition, favoring cyanobacteria. Our results indicate that nutrient excretion by detritivorous fish can be an important source of nutrients to open waters, especially when other sources of nutrients are reduced.

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“…The lake is dimictic and slightly acidic, with surface-water concentrations of DIC near 100 PM and total phosphorus near 0.15 PM (Caraco et al 1992). The surface area of the lake is 15 ha and its maximum depth is 10 m. The watershed of the lake (106 ha) consists of several large knobs; the largest of these knobs on the northwest side of the lake directly blocks wind from the predominant northwest direction (Winter 1984).…”

Section: Site Descriptionmentioning

confidence: 99%

Atmospheric exchange of carbon dioxide in a low‐wind oligotrophic lake measured by the addition of SF₆

Cole

Caraco

1998

Limnology & Oceanography

Self Cite

897

1,029

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Many freshwater lakes are supersaturated in CO, with respect to the atmosphere. This concentration gradient implies a net flux of CO, from the water to the air. The actual rate of gas exchange is governed by both this concentration gradient and the gas transfer coefficient, k. To directly measure k, we added the chemically and biologically inert gas, sulfur hexaflouride (SF,), to the epilimnion of Mirror Lake, New Hampshire, a small (15 ha), low-wind softwater lake. k was independent of wind speed over the 50-d summer stratification period and averaged 2.65 ? 0.12 cm h-I (95% CI; normalized to a Schmidt number of 600); k,, was better correlated to precipitation events than it was to wind speed. Our data support the idea that gas exchange across the air-water interface is largely independent of wind at low wind speeds. The surface water of Mirror Lake was persistently supersaturated in CO, with respect to the atmosphere. During a 3.5-year period the partial pressure of CO, in the surface waters of the lake averaged 726 + 39 patm (95% CI) and showed substantial seasonal variation (360-2,000 patm). Diel and day-to-day variation in CO, were very small compared to the CO, pool. We combined our estimates of k with weekly measurements of the partial pressure of CO, to estimate CO, gas exchange in the lake. Mirror Lake released from 26 to 50 g C m-* to the atmosphere each year, depending on the method of calculating k. Atmospheric CO2 exchange is a large term in the C economy of the lake-the most conservative gas flux estimate is about four times as large as outflow plus seepage of total dissolved inorganic carbon and 1.5 times as large as the export of dissolved organic C from the lake.

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New and recycled primary production in an oligotrophic lake: Insights for summer phosphorus dynamics

Cited by 80 publications

References 20 publications

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem

Atmospheric exchange of carbon dioxide in a low‐wind oligotrophic lake measured by the addition of SF₆

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New and recycled primary production in an oligotrophic lake: Insights for summer phosphorus dynamics

Cited by 80 publications

References 20 publications

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

Top-down and bottom-up controls on periphyton biomass and productivity in Lake Tanganyika

Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem

Atmospheric exchange of carbon dioxide in a low‐wind oligotrophic lake measured by the addition of SF6

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Atmospheric exchange of carbon dioxide in a low‐wind oligotrophic lake measured by the addition of SF₆