Showing papers on "Productivity (ecology) published in 1969"
126 citations
TL;DR: In this article, the primary production in Marion Lake is inversely related to the rate at which water enters the lake when light intensity is corrected to a standard level, thus seasonal variations in rainfall in southwestern British Columbia exert an appreciable influence on the annual productivity of the lake's phytoplankton.
Abstract: Primary production in Marion Lake is inversely related to the rate at which water enters the lake when light intensity is corrected to a standard level. Increased flushing rates reduce the phytoplankton standing crop thereby lowering the total primary productivity in the lake. Thus seasonal variations in rainfall in southwestern British Columbia exert an appreciable influence on the annual productivity pattern of the lake’s phytoplankton.
Lake water artificially enclosed within small areas of the lake produced algal blooms while phytoplankton standing crop in the rest of the lake remained low. Nannoplankton appear to have a selective advantage over larger, more slowly reproducing forms in Marion Lake. The production: biomass ratio for lake phytoplankton was used as an indication of the general type of limiting factor affecting the instantaneous rate of productivity in the lake.
94 citations
TL;DR: In a gravel pit in N.E. England the annual production of phytoplankton was measured with the 14C technique, and the gross production of the macrophyte Ceratophyllum demersum was calculated with the diurnal oxygen method.
Abstract: In a gravel pit in N.E. England the annual production (for 1967) of phytoplankton (1100 g carbon/M2) was measured with the 14C technique, and the gross production of the macrophyte Ceratophyllum demersum (600 g carbon/M2) with the diurnal oxygen method. Over the year the two communities were complementary, and high productivity by the macrophyte in summer succeeded high productivity by phytoplankton in spring. A second pond, in which macrophytes were scarce, contained more phytoplankton in summer but on an annual basis its phytoplankton production (500 g carbon/M2) was less than in the first pond. Ceratophyllum was found to cause greater shading of the phytoplankton beneath it than Potamogeton natans. Some observations were made on the vertical distribution of chlorophyll and phytoplankton productivity. Pe3loMe B BogoeMe B ceBepO-BOCTO'IHOil AHriirn ro,wiqam fpOAYKIUHR COCTaB1S1a B 1967r. llOOr C/M2. (143MepeHHq rPOBOAHJIHCb C ripH;MCeHeHHeM C14). BanIOBas IIPOAYKXHA MaKpO4ITTOB Ceratophyllum demersum, H3MepeHHaq CyTO'qHbIM KHCJIOPOAHbIM MeTOAOM, COCTaBjiqJia 600r C/M2. B TeieHRe roxAa HccneJAoBaHbI ,oiioJiHHTeJi]HO eri~e )asB KOMnJIeKCa MaapO4HTOB. lIx BbICOKaR IIpOAYKTHBHOCTb IIeTOM IBjiqeTCA CJIieJCTBHeM BbICOKOA IIPOXYKTHBHOCTH 4HITOrIJIaHKTOHa BeCHOA. BTOPOll npya, rAe MaKpo4HTbI 6buIR HeMHoro'HCjieHHbI, cogepwaii 6oJibmee KO3IIIeCTBO 4DHTOiaiiaHKTOHa JIeTOM, HO B TeqeHRe roxga ero HPOAYKIIHR COcTaBJIssia 500r C/M2 MeHBIIIe, 'IeM B iTePBOM BOaOeMe. YCTaHOBJIeHO, tITO Ceratophyllum cHJIiHee noAaBI5eT 4IHTOnIiaHKTOH, ieM Potamogeton natans. npoBeaeHBI HeKOTOpbIe Ha6fnioeHHA BepT1IKaJThHOrO pacnpeAejieHHR xnopowRina R HpOAYKTHBHOCTH UHTOnjiaHKTOHa. Manuscript accepted April 1969.
81 citations
59 citations
TL;DR: In the Baltic, some brackish water rockpools, heavily polluted by bird droppings, were investigated in order to study some of the general patterns of biochemical cycling of the nutrients.
Abstract: In the Baltic, some brackish water rockpools, heavily polluted by bird droppings, were investigated in order to study some of the general patterns of biochemical cycling of the nutrients. The seasonal variations of the following parameters were studied: salinity, temperature, rainfall, pH, algal biomass, detrital content, NH4-N, N02-N, N03-N, P04-P, suspended and soluble organic nitrogen and phosphorus. The diurnal variations of pH, P04-P and oxygen were measured. The faunal composition is discussed. The bird feces provided nutrients well beyond the needs of the algal biomass throughout the vegetation period. High concentrations of phosphate were always found, and this resulted in extremely low N/P ratios reflecting the chemical composition of the bird feces. Ammonia was always the dominating inorganic nitrogen compound and only during the period of maximum algal growth in the spring were considerable amounts of nitrate found. A possible inhibition of the nitrification processes resulting in an accumulation of ammonia is discussed. The high concentrations of ammonia might have a toxic effect on the algae, especially at the prevailing high pH-values. Most of the algal biomass was decomposed in the beginning of July. The diurnal variation of inorganic phosphate was found to be very large even in the absence of algae. This is mainly attributed to the activity of both autotrophic and heterotrophic bacteria. The difficulties in relating these fluctuations to productivity measurements are discussed. The nutritive value of the detrital layer, which consists mostly of fecal pellets, is discussed. Pe3IoMe
52 citations
TL;DR: In this paper, the respiration of the soil in situ was studied during a period of 15 months in four Eucabbus stands of diverse physiognomy and productivity, and it was found that respiration rates were low in winter, and during periods of drought in summer; they were high in spring, and were stimulated by precipitation during the summer.
Abstract: The respiration of the soil in situ was studied during a period of 15 months in four Eucabpbus stands of diverse physiognomy and productivity. Respiration rates were low in winter, and during periods of drought in summer; they were high in spring, and were stimulated by precipitation during the summer. Although soil respiration rates were not directly related to the organic matter content of the soil, to the amount of litter fall, or, in general, to the productivity of the stands as measured in terms of tree growth, the magnitude of the spring flush of respiration and the levels of respiration that were maintained during periods of summer drought were found to be related to stand productivity. The pattern of variation of the carbon dioxide content of the soil air differed markedly between stands, and there was a positive relationship between the productivity of the stands and the depth in the soil to which biological activity occurred.
27 citations
TL;DR: Primary productivity was measured by the radio-carbon method, its relation to the distribution of inorganic phosphate and dissolved oxygen off the south-west coast of India is discussed and dark bottle correction at lower levels of the euphotic zone in coastal waters is discussed.
Abstract: Primary productivity was measured by the radio-carbon method, its relation to the distribution of inorganic phosphate and dissolved oxygen off the south-west coast of India is discussed. The study was conducted during the post-monsson season which is associated with coastal upwelling. Productivity rates were generally high (807 mgC/m2/day), and so was the nutrient level in the euphotic zone. Inorganic phosphate was measured and taken as representative index of nutrients in general. Carbon assimilation rates were correlated with chlorophyll a, as well as with chlorophylls a, b plus c. Plant carotenoids were also measured but their role is not clear. Standing crop estimations failed to show any good agreement with carbon assimilation. Dark bottle correction at lower levels of the euphotic zone in coastal waters is discussed. The various results are interpreted from the point of view of light ecology. Fluctuations in productivity are mainly due to variations in incident solar radiation.
18 citations
TL;DR: The limnology, productivity and community metabolism of a series of beach and lagoon ponds in different stages of succession were studied on Presque Isle, a sandspit in Lake Erie at Erie, Pennsyl- vania, from 1960 to 1963, finding a trend toward lower pH and increased carbonates in beach ponds, and a general increase in species of Mollusca in older beach ponds and a decrease in lagoons.
Abstract: The limnology, productivity and community metabolism of a series of beach and lagoon ponds in different stages of succession were studied on Presque Isle, a sandspit in Lake Erie at Erie, Pennsyl- vania, from 1960 to 1963. The shallow, narrowly elongate ponds ranged from 1 to over 200 years of age. Organic matter, which has accumulated to a maximum of 0.8 m in one pond, results in reduction of size approx- imating 60% in 50 years and with a maximum reduction of 95% in 75 years. Significant macrovegetational characteristics include the replace- ment of initial submerged colonizers, like marl-forming Chara and Nitella, by Myriophyllum within 10 years, and the appearance of floating-leaved species in not less than 30 to 40 years. All ponds have a sand-ridge border, 1 to 3 m high, consolidated and dominated by cot- tonwood with bayberry as a secondary invader. The ponds are all moderately to well buffered alkaline systems with medium to high levels of carbonates; there is a trend toward lower pH and increased carbonates in beach ponds, toward lower pH and de- creased carbonates in lagoon ponds. Phytoplankton density is greatest in late July to early August with lower density in older beach ponds. The summer flora is dominated by chlorophytes and cyanophytes, the fall and winter by chlorophytes or chrysophytes, notably diatoms, which also dominate the spring flora. Species diversity is greatest in midsummer, least in autumn and spring in all ponds, with increased diversity in older lagoon ponds and reduced diversity in older beach ponds. Carotenoid/chlorophyll ratios showed no consistent pattern annually, nor with stage of succession. Annual net (14C) productivity is lower in older beach ponds; in lagoon ponds, the youngest and oldest had higher net productivity than intermediate-aged ponds. Gross productivity is lowest in the' oldest beach pond and in the youngest and oldest lagoon ponds. Standing crop of chlorophyll a showed considerable variation annually and by stage of succession. Colonization by invertebrates is largely via secondary invasion sub- sequent to the establishment of the ponds. Some groups of Malacos- traca, Coleoptera, Diptera and Odonata tend to increase with advancing succession, others to decrease, still others to increase and then decrease. There is a general increase in species of Mollusca in older beach ponds and a decrease in lagoon ponds. Community metabolism, estimated from studies on diurnal rate of change of oxygen, showed a change in the ratio of photosynthesis to respiration from slightly over 1.0 in the youngest pond to 0.33 in the oldest pond. Different rates of increasing heterotrophy are noted in
13 citations
01 Jan 1969
11 citations
01 Jan 1969
TL;DR: An extensive study of the hydrobiology of the Colombo Lake was initiated by the authors in May 1969 as a contribution to the International Biological Program (Productivity of freshwater communities) by the Department of Zoology, Vidyalankara University of Ceylon, Kelaniya.
Abstract: An extensive study of the hydrobiology of the Colombo Lake was initiated by the authors in May 1969 as a contribution to the International Biological Program (Productivity of freshwater communities) by the Department of Zoology, Vidyalankara University of Ceylon, Kelaniya. The Colombo Lake often referred to as the Beira Lake covers an area of approximately 160 acres. The water is usually very turbid with a greenish blue appearance due to the presence of large quantities of blue green algae.
TL;DR: A quantitative study of the microbial biomass of an aquatic environment may be approached basically in one of two ways, by measuring the number or mass of organisms which are present at a given time in a given place (this quantity is often referred to as the "standing crop"), or by measuring productivity, i.e., either gross or net production of biomass as mentioned in this paper.
Abstract: A quantitative study of the microbial biomass of an aquatic environment may be approached basically in one of two ways, by measuring the number or mass of organisms which are present at a given time in a given place (this quantity is often referred to as the "standing crop"), or by measuring productivity, i.e., either gross or net production of biomass. Primary productivity is usually expressed in terms of the total photosynthate produced per unit time in a given place. Its estimation is most often based on either the rate
TL;DR: Primary productivity studies were conducted at the White Sea Biological Station, Payakonda, during summer 1966; oxygen and radio-carbon methods were employed and the oxygen method gave higher results.
Abstract: Primary productivity studies were conducted at the White Sea Biological Station, Payakonda, during summer 1966. Oxygen and radio-carbon methods were employed; the oxygen method gave higher results. Variations in productivity due to tides were measured; low tide waters supported higher productivity rates.
Dissertation•
01 Jan 1969
TL;DR: In this paper, the authors evaluated the effects of mechanical evaporation barriers on fish growth and pond productivity and found that barrier coverages above 5O7 reduced fish growth, fish survival, aquatic insect yields, gross photosynthesis, dissolved oxygen concentrations, temperatures, and habitat areas.
Abstract: Four experiments were conducted to evaluate some of the effects of mechanical evaporation barriers on fish growth and pond productivity. Barrier coverages above 5O7 reduced fish growth, fish survival, aquatic insect yields, gross photosynthesis, dissolved oxygen concentrations, temperatures, and habitat areas. These reductions appeared to correlate with decreased amounts of light entering each pond. Zooplankton numbers, phytoplankton chlorophyll concentrations, pH, and turbidity measurements were not significantly affected at any coverage level.
01 Jan 1969
TL;DR: Estimation of production rates for planktonic and benthic crustaceans and invertebrates has received considerable attention, and methods with a fair degree of general applicability have been developed: the oxygen and 14C methods for phytoplankton productivity and the growth methods of Ricker and Allen for fish.
Abstract: Increasing effort is being applied to quantitative studies in the production ecology of freshwater ecosystems, most particularly to the measurement of production rates. The three major groups of organisms in these environments -plants, invertebrates, and fish- approximate to the first three levels of a classic trophic structure. Estimation of production rates for the first and last of these have received considerable attention, and methods with a fair degree of general applicability have been developed: the oxygen and 14C methods for phytoplankton productivity and the growth methods of Ricker (1946) and Allen (1949, 1951) for fish. Methods and data for aquatic invertebrates, however, are relatively scarce. Methods involving essentially the summation of mortalities through various life-history stages have been applied to planktonic and benthic crustaceans, and Ricker's and Allen's growth method for fish promises limited application to invertebrate animals with certain types of life history. Direct estimates of production rates of benthic invertebrates are rare, more so for an entire benthic fauna, although a small number have been published. In some cases, the turnover ratio, or ratio of production to standing crop, has been presented along with these production-rate estimates. Usually this ratio has been determined over a single year or season, sometimes simply over the life cycle of the subject species. When available turnover ratios for benthic invertebrates are compared, including those given by an author and those calculated from the author's production and standing-crop data, and expressed over a complete life cycle only, they