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Production rates of epiphytic algae in a eutrophic lake
Abstract
During three complete annual cycles, chlorophyll a concentrations and primary production rates of algae epiphytic on Phragmites australis in eutrophic Lake Belau were determined. Primary production rates reached a peak during spring due to the growth of diatoms and filamentous green algae. The chlorophyll-specific rates of photosynthesis were significantly higher during periods of stratification and increased exponentially with an increase in water temperature. No photoinhibition was observed, even at high irradiances. I
k values were higher in summer than during periods of circulation.
... This is in accordance with Albay and Aykulu (2002). Similar results were found by Muller (1996) who recorded high numbers of filamentous chlorophytes (Oedogonium spp., Spirogyra spp. and Mougeotia spp.) in shallow German lake. ...
... For example, a change in level of light intensity on microenvironment can affect vertical colonization of these organisms (Villeneuve et al. 2010). That is, the occurrence of certain species depends on the solar radiation that penetrates the water column as well as the self-shading within the periphytic algal community (Müller 1996;Albay and Akçaalan 2008). Nymphaea has a large leaf area above its petiole, which leads to a reduction in light intensity on its submerged petiole and consequently on the periphytic algae diversity that it hosts. ...
Aquatic macrophytes have a key role in aquatic ecosystems because they can structure biotic communities by offering habitat for many aquatic organisms, especially periphytic algae. The aim of this study was to evaluate the periphytic algal structure (taxonomic diversity and functional traits) in two macrophytes with different architectures (Nymphaea L. and Cabomba Aubl.). We tested the hypothesis that architectures of the Nymphaea and Cabomba affects in a different way the periphytic algae community, increasing taxa richness and density in more complex substrate (Cabomba), and that the taxa composition, life form and adherence form are different between both types of macrophyte. In addition, we tested whether there are higher algae density without a fixed structure on complex substrate. The study was conducted in Caxiuanã National Forest, one of the largest protected areas in the Pará state, Eastern Amazon. The samplings were made in blocks with two levels (Nymphaea and Cabomba) under the same abiotic conditions. Our results showed that there was significant difference in taxa richness and density between macrophytes, with higher values in Cabomba. We found more exclusive species in more complex substrate (70, Cabomba), than less complex substrate (19, Nymphaea). Furthermore, species composition, life form and adherence form also showed differences between macrophytes, with higher algae density without a fixed structure on Cabomba. These results indicated that when the source of algal propagules is the same (mixed bank of macrophytes), the habitat complexity tightly influenced the diversity of periphytic algae community.
... Laugaste and Reunanen (2005) also found that maximum algal biomass was estimated in autumn. Bacillariophyceae was the most dominant algal group in this study during the four seasons, this may be attributed to the highly competitive advantage on the nutrients over the other classes of algae (Muller, 1996), followed by Chlorophyceae, Cyanophyceae, Euglenophyceae, Charophyceae and Dinophyceae. These results were in agreement with Elewa et al. (2009) and Shehata et al.(2008), who pointed out that most of the recorded phytoplankton of Rosetta Branch, dominated mainly by Bacillariophyta and Chlorophyta, while Pyrrophyta and Euglenophyta were persisted as rare forms. ...
... Bacillariophyceae was recorded a highest number of species compared with the other divisions of epiphytic algae on the two host plants. The highest diatoms occurrence may be attributed to the highly competitive advantage on the nutrients over the other classes of algae (Muller, 1996). Generally, the highest total algal counts were recorded on the stem of E. stagnina, while the lowest total algal cell counts were recorded on P. australis. ...
The epiphytic algae on two aquatic macrophytes namely, Phragmites australis and Echinochloa stagnina and related physico-chemical properties of some water bodies at Assiut, Egypt; as well as, the qualitative and quantitative composition of epiphytic algae were studied. Sixty seven taxa of epiphytic algae were recorded during the current study, of which 45 species belong to Bacillariophyceae, 14 species to Chlorophyceae, and 8 species to Cyanophyceae. Some epiphytic algal taxa were observed mostly frequent among the study sites. These were Melosira granulata, Melosira islandica, Synedra affinis, Synedra ulna (Bacillariophyceae) and Oedogonium sp. (Chlorophyceae). Generally, the highest species richness and total algal counts were recorded on the stem of E. stagnina, compared with that recorded on P. australis. Seven diversity indices were obtained that comprise Margalef ́s Index, Shannon-Wiener diversity, Pielou’s evenness, Fisher’s Index, Simpson Dominance index, Simpson's Diversity Index and Berger-Parker index. The Jaccard similarity index appeared a difference in the algal species between the studied macrophytes. The distribution and diversity of epiphytic algal taxa varied among macrophytes as well as characterized by spatial variation with a difference in electrical conductivity, total dissolved solids and nitrates as the most significant abiotic factors.
... As Bouvy et al., (1997) pointed out that periphyton and phytoplankton may exchange organisms and compete for nutrients. Similar results were found by Müller (1996) who recorded high numbers of filamentous chlorophytes (Oedogonium spp., Spirogyra sp. and Mougeotia sp.) in a shallow German lake. It is worthwhile the point out that when Anabaena reached to high numbers in periphyton Secchii depth decreased to 0.8 m in L. Iznik. ...
... This allows other invasive species to succeed temporarily and also supports algal growth (Klötzli 1971). Müller (1995Müller ( , 1996 found that shading by P. australis had little effect on the growth and chlorophyll content of epiphytic algae, thereby permitting their long-term growth. ...
Phragmites australis (Cav.) Trin. ex Steud. - common reed, is a perennial, emergent aquatic plant with annual cane-like stems developed from an extensive rhizome system. It grows in low-lying wet areas such as fresh and salt-water marshes, drainage ditches, shallow lake edges, sandy banks, roadsides, woodlands and rocky places. Stems can reach up to 6.0 m in height, vary in diameter from 4 to 10 mm and have 10 to 25 cm long hollow internodes. Clones are extended by perennial rhizomes with extensive aerenchymatous tissue that supplies oxygen. Roots develop from rhizomes and other submerged parts of shoots. Leaves are smooth, alternate with narrow-lanceolate laminae, 20 to 70 cm long and 1 to 5 cm broad, and tapering to long slender points. The inflorescence is a terminal panicle, often 30 cm long, dull purple to yellow, with main branches bearing many spikelets. Seed production and germination are extremely variable and comparatively rare in many populations. Phragmites australis carries out photosynthesis through the C3 pathway (or a variation thereof). Studies of genetic variation through isozyme and other molecular methods suggest that the populations are very closely related, and that variation in the metapopulation is small. Chloroplast DNA sequences of two non-coding regions indicate that non-native introduced genotypes of P. australis have displaced native genotypes in parts of North America. Phragmites australis often forms extensive monocultures in North America. As a consequence, habitat quality and species diversity have been documented to decline. However, in roadside populations it is effective in taking up many typical heavy metals that originate from nearby highways and buildings. Phragmites australis is found in all Canadian provinces and the Northwest Territories, but not in the Yukon Territory or Nunavut. The infestation of P. australis is most severe in the Great Lakes region and its migration is primarily mediated through rivers, canals and waterways but roadways are increasingly becoming important. Changes in the water regime have been linked to its success and could ultimately result in changes to the floristic composition of a habitat. Rodeo™, an aqueous solution of the isopropylamine salt of glyphosate, is most frequently used to control P. australis populations. Other methods of control include cutting, burning, and drainage of the species' habitat. As P. australis is considered to be invasive in North America, introduction of biological control agents is now being investigated.
... As Bouvy et al., (1997) pointed out that periphyton and phytoplankton may exchange organisms and compete for nutrients. Similar results were found by Müller (1996) who recorded high numbers of filamentous chlorophytes (Oedogonium spp., Spirogyra sp. and Mougeotia sp.) in a shallow German lake. It is worthwhile the point out that when Anabaena reached to high numbers in periphyton Secchii depth decreased to 0.8 m in L. Iznik. ...
Invertebrate - epiphytic algae interaction in the periphyton of Potamogeton pectinatus L. and Potamogeton perfoliatus L. collected from the littoral of Lake İznik was investigated between May 1993 - November 1994. A close relationship was observed between some invertebrates and algae in the periphyton. A decrease was observed in stalked and tubes diatom density whilst nematodes in Potamogeton perfoliatus periphyton community increased. An unexpected negative effect of Rotifers and Ciliates on erect and cocconeis type diatoms were recorded in addition to Rotifers pressure on prostrate diatoms. Although the taxonomic composition of epiphytic algae and invertebrates of Potamogeton pectinatus was similar to that of P. perfoliatus, interaction between these groups differed significantly. A weak negative effect of nematodes and Rotifers on erect diatoms was found besides Ciliates and Rotifers pressure on stalked diatoms and distinct influences were found between Ciliates and cocconeis type diatoms. Since other invertebrate groups were scarce in both periphyton communities, no significant interaction with epiphytic algae was found. In addition to the effects of water temperature, high pH, light, water quality and structure of the macrophytes significantly affected the colonization of the epiphytic algae and their grazing by the invertebrates.
... Irradiance level can affect the epiphytic algal productivity (Hill et al. 1995). The influence of the light intensity depends upon the solar energy that penetrates the water column in the littoral zone as well the self-shading within the periphyton (Müller 1996). It is worthwhile to point out that most part of the light can be either absorbed or scattered into a different direction in shallow lakes. ...
The aim of this paper is to determine and compare the environmental factors controlling vertical colonisation of periphyton on Sparganium erectum in a shallow eutrophic turbid lake, Manyas Lake, and an oligo-mesotrophic deep lake, Sapanca Lake, Turkey during the July 1997--November 1998. To investigate the effect of the environmental factors on periphyton colonization on S. erectum, the stem was cut above the rhizomes and subdivided into three equal sections. Multivariate statistical analyses have been applied to clarify relationships between environmental variables and periphyton colonization on S. erectum. Results indicated that physical disturbance and trophic level of the lakes influenced the colonization of the periphyton. Among the measured parameters, low light intensity, total suspended solids, temperature and water level fluctuation were observed as driving factors in Manyas Lake whereas nutrient deficiency was found as key factor in Sapanca Lake. The zonation of the periphyton, density, composition and dominant/subdominant taxa were significantly different in these lakes. However, Oedogonium sp., Mougeotia sp., Cylindrocapsa sp., Cladophora glomerata (Linn.), Aulacoseira italica (Ehr.) Simonsen, Melosira varians C. Agardh, Navicula tripunctata (O.F. Müller) Bory and Fragilaria ulna (Nitzsch) Lange-Bertalot were found as dominant species at all sections of S. erectum both in Manyas Lake and Sapanca Lake. It can be thought that these species have a broad range of tolerance to several physical, chemical and hydrologic disturbances. This is the first study to introduce how much the water quality and hydrologic drivers have affected vertical colonization of periphyton on S. erectum in two lakes with different mixing regimes.
Research papers on lake and reservoir management issues are reviewed. Specific topics include general water quality, operations, lake models, remediation measures, and biota. Studies of potential lake water quality impacts associated with global climate change also are included.
I examined whether light availability mediated the extent to which herbivory by green frog tadpoles (Rana chmitans) affected lower trophic levels in a fishless pond in central Kentucky. An enclosure experiment manipulating tadpole presence/absence and light (shaded vs. unshaded) showed that tadpoles can significantly reduce benthic algal biomass in light levels that mimic springtime canopy conditions. Tadpoles, however, had little affect on algal species composition. Grazing did not indirectly affect nutrient (NO3 and PO4) concentrations in experimental treatments, probably because ambient concentrations were beyond growth-limiting levels.
The vertical distribution of gross primary production rates of periphyton communities was determined based on changes in the oxygen concentration. The gross primary production conformed to the colonization pattern of the epiphytic algae on submerged shoots of Phragmites australis. The algae produced the most on stem sections that grew from 0.2 to 0.5 m deep in the littoral zone. The PB rates, however, decreased on these middle sections of the stems due to increasing self-shading by the periphyton. Although high gross oxygen production rates were determined during the hours of incubation, an oxygen deficit was calculated for the full 24 hours periods on all days of the investigations at the time the algae peaks occurred during the spring.
Colonisation of epiphytic algae on the common reed (Phragmites australis) and on glass slides were studied during a twenty-four week exposure period in a shallow, turbid lake, Manyas (Bird Paradise), western Turkey. Slides were used as substrate and positioned near the reed stands. To understand the effect of light on the colonisation of periphyton on P.australis and artificial substrates, three perspex frames (each frame consisted of 60 glass slides) were positioned at depths of ca. 25 cm, 50cm and 75cm, called `upper', `middle', and `lower section', below the water surface. For the determination of periphyton and chlorophyll a content three new stems, which were cut above the rhizomes and subdivided into 25cm, and three slides were taken from the each frame at four-weeks intervals. The rapid increase was recorded in algal species richness and biovolume on P.australis, whereas relatively slow colonisation was observed on glass slides. Filamentous centric diatoms, (mainly Aulacoseira italica and Melosira varians) was the dominant group, accounting for 29 to 82% of the total algal biovolume, and adnate diatoms (Surirella spp.), filamentous, and Chlorococcal chlorophytes (Pediastrum spp. and Oedogonium spp.) were the subdominant groups on the artificial substrate during the colonisation period. Pennate diatoms, mainly prostrate/motile and filamentous diatoms (Navicula tripunctata, Navicula radiosa, and Aulacoseira muzzanensis), and filamentous cyanobacterium (Planktolyngbya limnetica) were recorded as dominant groups on the reeds. Generally, epiphytic algal biomass was higher upon P.australis than upon glass slides. However, after the twelfth week colonisation biomass increased less than on earlier stages on the P.australis. Total algal biovolume was positively correlated with chlorophyll a and with Soluble Reactive Phosphorus (SRP), and negatively correlated with the water level and Secchi disc depth.
The influence of light and temperature on photosynthetic rate as measured by C14O2-fixation of marine benthic diatoms was investigated, using both intact sediment samples (Marshall et al., 1973) and suspensions of diatoms harvested by a lenstissue technique (Eaton and Moss, 1966). After C14-incubation, sediment samples were filtered, burned in a sample oxidizer, and their activity determined in a liquid scintillation counter. Photosynthetic rate of mixed field populations is saturated by a light intensity of approximately 10,000 lux; at still higher light intensities no photoinhibition was found. In contrast to the mixed field populations, unialgal cultures of the benthic diatom Amphiprora alata Ktz. exhibited strong photoinhibition at higher light intensities (10,000 to 60,000 lux). Within a range of 4 to 20C, the photosynthetic rate increased about 10%/Co. No differences in photosynthetic pattern were observed between epipelic and epipsammic species.
A one-year study of phytoplankton, primary production and related physical and chemical factors was made in a Swiss basin of Lake Lugano (Lago di Lugano). The chlorophylls and 12 carotenoids were analyzed with a TLC technique. The carotenoid monitoring was considered to be particularly interesting, because the role of these pigments in freshwater algae is still very poorly documented by field studies. The dependence of photosynthesis on several factors was statistically evaluated. Evidence was found of light-adaptation phenomena. The variations of photosynthetic activity and efficiency largely depended on the light regime in the few days before the field observations and on the cellular content of chlorophylls and single carotenoids, whose concentrations in their turn were closely linked with light, temperature, average cell size, and with the actual species assemblage.
This tutorial was designed for nonbiologists requiring an introduction to the nature and general timescales of phytoplankton responses to physical forcing in aquatic environments. As such, an effort was made to highlight biological markers which might assist in identifying, measuring and/or validating physical processes controlling the variability in the distribution, abundance, composition and activity of phytoplankton communities. Given the recent advances in environmental optics and remote sensing capabilities, a special emphasis was placed on the nature and utility of phytoplankton optical properties in current bio-optical modelling efforts to predict temporal and spatial variability in phytoplankton productivity and growth.
A diatom-dominated population of epiphytic algae was studied in an oligotrophic lake to determine the factors which limit epiphyte growth and to measure their contribution to primary productivity. Algae were collected from plants growing at four sites in Lake George, N.Y., during the spring, summer, and fall of 1974. Samples were taken from 3 m, corresponding to the depth at which macrophytes were most productive. Algae exhibited an optimum temperature for HCO(3) uptake at 30 C, although the summer littoral lake temperature ranged from 18 to 25 C. Light saturation occurred at an intensity of 8,608 lux, approximating the environmental intensity at the depth from which algae were taken. Epiphytes exhibited their maximum photosynthetic capacity of 0.6 mg of carbon fixed/m of macrophyte surface area per h in the early afternoon in mid-August. They assimilated approximately 5% as much inorganic carbon as the macrophytes from which they were taken. Epiphyte population densities followed the seasonal growth patterns of the macrophytes, with maximal leaf colonization remaining essentially constant relative to the leaf position on the plant. There was little change in density between sampling sites at any given time. Productivities of epiphytes from bottom leaves were 10-fold greater than those of epiphytes from top leaves. Addition of PO(4), NO(3), NH(3), Si, and SO(4) had no stimulatory effect on photosynthesis. Addition of HCO(3) stimulated photosynthesis greater than 30%, suggesting that carbon may be a limiting nutrient for epiphytic algae in Lake George.
Just as the composition of phytoplankton assemblages depends upon the presence and relative abundances of populations of individual species, so temporal changes in their composition are brought about by differences in the relative rates of augmentation and attrition of each population. These rates respond to a complex of interactions among various physical, chemical, and biotic environmental factors, operating at a variety of intensities and frequencies. This chapter addresses the impact of essentially physical variables on the population dynamics of individual species and it seeks to establish the particular properties of the organisms for which each selects. Factual information relating the performances of algae to quantifiable aspects of the physical environment is drawn largely from observations made in controlled laboratory experiments. Realistic potential combinations of the relevant physical factors are suggested in order to simulate the likely responses of specific populations in natural waters. The outcomes of such simulations are then compared with the PEG-model of phytoplankton succession (see Section 1.2) propounded by Sommer et al. (1986), which was originally elaborated to explain the pattern of seasonal change in species dominance, as regularly observed in Lake Constance (the Bodensee). A concluding section assesses the role of physical factors in regulating seasonal succession of phytoplankton generally. At the end of the chapter, beginning on page 52, there are three appendices. The first one, Appendix 2.1, defines the units used in this chapter. The second, Appendix 2.2, identifies the symbols used, and Appendix 2.3 explains the abbreviations used for algal names.
Epiphytic algal and bacterial in situ community metabolism and physiological-nutritional relationships of macrophyte-epiphyte systems were investigated in the littoral zone of a small temperate lake from April 1968 through May 1969. Annual primary productivity, chemo-organotrophy of dissolved organic compounds, and field and laboratory studies of macrophyte-epiphyte interactions were monitored by carbon-14 techniques. Productivity measurements of epiphytic algae on artificial substrates colonized in emergent (Scirpus acutus Muhl.) and submergent (Najas flexilis L. and Chara spp.) macrophytic vegetation sites were compared over an annual period with pigment (corrected chlorophyll a and total plant carotenoids) estimates of biomass. Changes in biomass are not proportional to changes in photosynthetic activity, except during periods of intense productivity. The mean daily productivity of epiphytic algae was higher per unit macrophyte surface area of emergent plants (336 mg C m^-^2 day^-^1) than on submerged plants (258 mg C m^-^2 day^-^1). Mean daily productivity per unit area of the littoral zone, for all of the macrophytic surface area colonized, was 195 and 1,807 mg C m^-^2 day^-^1 in the Scirpus and Najas-Chara dominated sites, respectively. The total annual production by algal epiphytes in the Scirpus and Najas-Chara dominated sites was 2.86 and 35.00 g C m^-^2 of lake surface year^-^1, respectively. Estimates of annual net production of macrophytes and epipelic algae, derived from studies undertaken during the same time period as reported in this study, indicate that epiphytic algae were responsible for 31.3% of the total littoral production. The epiphytic algae were responsible for 21.4% of the total annual production for the whole lake when the production of the pelagial phytoplankton was added to that of the littoral communities. In comparison to the pelagial phytoplankton alone, the algal epiphytes fixed an amount of carbon equivalent to 75% of the phytoplankton production over the annual period. These results indicate that algal epiphytes on submerged macrophytes may be one of the dominant primary producers in shallow-water ecosystems and may be comparable to the phytoplankton. Deposition of ^1^4C-monocarbonates during in situ productivity measurements represented 38.5-71.7% of the total intracellular fixed carbon. Acidification of ^1^4C-productivity samples by rinsing with dilute hydrochloric acid (0.001 N) removed 24% of previously incorporated carbon and is not recommended as a routine procedure. Physiological interactions in macrophyte-epiphyte systems were investigated by bioassay procedure. Inorganic iron added at less than 10 @mg liter ^-^1, and at 100 @mg liter^-^1 in combination with organic compounds of chelatory or complexing ability, stimulated photosynthesis of epiphytic algae. Bioassay experiments in which vitamins, trace metals, and inorganic phosphorus were added to algal photosynthesis. Chlorophyll a, corrected for pheopigment degradation products, and total plant carotenoid levels are among the highest standing crops reported in the literature (annual maximum of chlorophyll a = 7.3 g m^-^2; plant carotenoids = 40.7 SPU m^-^2). Maximum concentrations were found during winter under ice cover. Epiphytic bacterial chemo-organotrophy with glucose and acetate substrates was measured at concentrations of 11-160 @mg liter^-^1 and evaluated through Michaelis-Menten enzyme kinetic analysis. First-order active transport kinetics dominated throughout the annual period. Uptake of acetate (submerged plant site, mean rate = 893 @mg liter^-^1 hr^-^1 dm^-^2; emergent plant site, 106 @mg liter^-^1 hr^-^1 dm^-^2) was greater than that of glucose (submerged plant site, 586 @mg liter^-^1 hr^-^1 dm^-^2; emergent plant site, 54 @mg liter^-^1 hr^-^1 dm^-^2). Scirpus acutus was labeled in situ during photosynthesis with natural concentrations of carbon dioxide (as ^1^4C). Epiphytic uptake of ^1^4C-labeled, extracellular products of macrophytic origin was determined. Extracellular release of ^1^4C-labeled organic matter was followed at various depths in the littoral water column. The nature of the extracellular release and the amount of ^1^4C fixed by the macrophyte and transferred into the epiphytic complex suggests nutritional interactions that may be prevalent in other macrophyte-epiphyte systems. Najas flexilis, germinated and grown under axenic conditions in a defined medium, was labeled during photosynthesis and placed into the center section of Plexiglas chambers separated by membrane filters free of organic carbon contamination. Over a 3.75-hr incubation interval, a mean of 7% of the total intracellularly fixed carbon was excreted as ^1^4C-labeled dissolved organic carbon. Cultured algal and bacterial epiphytes, separately and mixed in simulated natural communities, were able to utilize these extracellular products when placed into chamber sections adjoining the labeled Najas. The amount of extracellular products utilized by the mixed algal and bacterial communities changed with time, depending on the composition of the epiphytic community. The results suggest interspecific interactions where competition for specific external metabolites or organic solutes may have existed, or where toxic extracellular products may have accumulated. Laboratory uptake of low concentrations of glucose and acetate-^1^4C at 5@?, 11@? to 12@?, and 21@? to 23@? C by separate and mixed cultures of algal and bacterial epiphytes showed that uptake was strongly influenced by temperature, except at low temperatures where transport and diffusion mechanisms seemed to be inactivated. A sessile bacterium, Caulobacter, however, showed a highly efficient uptake system for both substrates under cold conditions. Uptake of both substrates by mixed cultures of algae and bacteria showed that bacterial uptake of both substrates by mixed cultures of algae and bacteria showed that bacterial uptake was little influenced at low substrate concentrations by the presence of algae. Epiphytic algal uptake following kinetics of simple diffusion was, however, increased in the presence of bacteria, suggesting uptake of ^1^4CO"2 previously respired by the bacteria. Macrophyte-epiphyte metabolism may be an important source of dissolved organic materials and extracellular metabolites and thus may help to sustain high levels of primary productivity and chemo-organotrophy in lakes.
Synopsis
Photosynthetic productivity of phytoplankton in Loch Leven was studied over a 4-year period (1968–71), using the oxygen light and dark bottle technique. Marked seasonal changes in hourly and daily rates of gross photosynthetic productivity are described within the range 0·02 to 1·59 g O 2 /m ² .h and 0·4 to 21·0 g O 2 /m ² .day respectively. Hourly rates are shown to be relatively insensitive to variations in surface light intensity, whereas daily rates are influenced to a considerable extent by the duration of incident radiation (daylength).
The phytoplankton itself exerts a dominant influence on underwater light penetration, accounting for ca 75 per cent of light extinction at highest crop densities. This self-shading effect contributes to the poor correlation observed between crop density and areal gross productivity. The chlorophyll a content per unit area in the euphotic zone often approached its estimated theoretical limit of 430 mg/m ² .
In general, increase in photosynthetic capacity (per unit content of chlorophyll a ) accompanied increase in water temperature. During certain periods an inverse relationship between photosynthetic capacity and population density was evident. Reduction in photosynthetic capacity is attributed, in part, to the high pH values (> 9·5) with concomitant CO 2 -depIetion associated with dense phytoplankton crops.
Estimates of net photosynthetic productivity were frequently zero or negative, even over periods when algal populations were increasing and dissolved oxygen and pH values were above their respective air-equilibrium values. Underestimation of gross photosynthesis due to photochemical oxidation, photorespiration or the use of stationary bottles could not account for this apparent anomaly. The most probable sources of error in the estimates of net photosynthetic productivity are discussed.
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Photosynthetic quotients, derived from simultaneous measurements of oxygen production and inorganic carbon fixation (carbon-14), were measured on blooms of phytoplankton in large (1.28 m3) algal tanks. The blooms were induced by the addition to natural sea water of inorganic nitrogen, phosphorus and silicon (N:P: Si = 15:1:4) with an initial nitrogen concentration of ca. 20 μg-at N l-1as either nitrate, ammonium, or a mixture of both. Conventional photosynthetic quotients in the range 1.0-1.3 were observed under conditions of ammonium assimilation. Quotients of up to 2.25 were, however, observed when nitrate was assimilated. Correction of the oxygen production data for nitrate reduction, using the stoichiometric ratio of 2 moles of oxygen produced for every mole of nitrate reduced, lowered these photosynthetic quotients to more conventionally acceptable values of about 1.25. The inaccuracies in measurements of primary planktonic production using the oxygen technique caused by nitrate reduction are discussed.
The seasonal growth of epiphytic algae colonizing artificial cellulose acetate substrates positioned in a stand of Scirpus acutus Muhl. and in a zone of Potamogeton pectinatus L. in a marsh pond was quantified in terms of 14C photosynthetic uptake, cell volume, cell surface area, dry weight, and chlorophyll a, protein, carbohydrate, and lipid content. Standing crop and productivity increased at both sites in September and October, after generally low summer growth with the exception of the occurrence of heterocystous blue-green algae at the Potamogeton site in July. Factor analysis of interrelationships among the various parameters suggested that cell surface area was more directly related to productivity and various standing-crop parameters than was cell volume.
Abstract The effects of biomass,accumulation,and community,age on the photosynthesis-irradiance,re- sponse of periphyton were examined,in developmental,sequences from three stream locations that differed in canopy,cover. Photosynthesis-irradiance,(P-Z) curves for four developmental,stages from each location were constructed from 14C uptake at six irradiances (22-1,100 pmol quanta m-2 s-l) in the laboratory. Photoinhibition in the periphyton from the two shaded sites declined with development, indicating that self-shading significantly influenced photosynthesis in older communities. Photoinhibition was absent, however, in all of the developmental stages from the high light site. Maximum photosynthesis (P,,,,,) and slope ((x) of the light-limited portion of the chlorophyll-specific light response decreased > 40% in developing periphyton at all sites. Significant negative correlations between biomass and biomass-specific P,,,,, suggested that light or metabolic substrates became,progressively more limiting during development. Although there was little com- munity-level evidence of shade adaptation during development,(photosynthesis did not saturate at lower light intensities as development proceeded), periphyton understories appear to retain considerable photosynthetic potential despite significant shading by upper layers. Streams,are catastrophic,ecosystems where,floods periodically scour and over- turn substrates, resetting successional pro- cesses in periphyton. The impact of frequent floods is such that quantity of periphyton in many,streams is largely a function of the time elapsed since the last major flood (e.g. Tett et al. 1978). Although the changes,in
has constituted an obstacle to the causal analysis of many aspects of phytoplankton ecology. Most measurements on photosynthetic rates of phytoplankton have been carried out under field conditions in which the relevant physical variables (notably light intensity) were inadequately known. Moreover, such experiments have generally utilized mixed natural populations whose history was little understood. This paper is concerned with information on the photosynthetic characteristics of three freshwater planlkton diatoms derived from experiments in the English Lakes. Photosynethtic behaviour of the diatoms, recorded from exposures at varying depths in the lakes, is analysed in terms of the photosynthetic characteristics of the species and the environmental conditions of underwater radiation and temperature. In certain aspects, the interpretation has been aided by supplementary data from laboratory experiments. Cultured populations of one species, Asterionella formosa Hass., have been used as the standard material in this work. With the photosynthetic characteristics of this material the photosynthetic behaviour of various natural populations of the same species, of known history, have been compared. A further, inter-specific, comparison has been made with the photosynthetic characteristics derived for the diatoms Fragilaria crotonensis Kitton (cultured population) and Melosira italica (Ehr.) Kiitz. subsp. subarctica 0. MUll. (natural population).
Shallow water algal turf communities are the major primary prcducers on coral reefs. High rates of primary production are maintained despite extremely high light intensities and exposure to ultraviolet wavelengths. The relationships between the light inter(sity and primary production in these assemblages are typical of algae adapted to a high light enrironment [low LY (initial slope), high Ik (saturating light intensity), and high Z, (compensation joint light intensity)]. Seasonal variations in algal standing crop due to herbivory and daylength result in some characteristic photoadaptive changes in (Y, Ik, and I,, and changes in Pnetmax rate s (maximum net photosynthetic rate achieved at light saturation) on both a chlorophyll a and :m areal basis. Exposure to UV wavelengths results in significantly higher respiration rates but 10 changes in cy, Pnet,,, or I,, when compared with these parameters for the same algal commur uties incubated at the same light intensities without UV wavelengths. The apparent lack of photoinhibition in these algae allows calculation of the daily integrated production from the P vs. I llarameters. This integrated production is highest in July (3.1 -t 0.2 g C m-2 d-l) and is reduced by 30% from this maximum in December (2,l +- 0.1 g C m-2 d-l).
1. The vertical distribution of chlorophyll in epiphyton on Phragmites australis showed a peak in the middle sections of the submerged parts. Just below the water surface and above the sediment, chlorophyll concentrations were much less.
2. During winter and early spring, loosely attached diatoms were predominant just below the water surface and on the middle sections of the Phragmites plants. Near the bottom, adnate diatoms, parenchymatous thalli of chlorophytes and cyanobacteria were abundant.
3. At high photosynthetic active radiation (PAR) during May, filamentous species of Ulpthricophyceae and Zygophyceae developed dense populations on the middle sections of the stems.
4. Primary production rate was proportional to chlorophyll concentration although production maxima were recorded above the biomass maxima.
5. Where illumination was low, the chlorophyll‐specific rate of photosynthesis ( P B rate) decreased proportionally with the vertical decrease of PAR in the littoral zone, independent of the chlorophyll concentration on the stems.
6. When illumination was high, the P B rate decreased as biomass increased, and was independent of surface radiation.
7. The dependence of primary production rate on chlorophyll concentration produced a saturation curve with a maximum production at 4.6 μgC cm ⁻² h ⁻¹ .
The seasonal variation in periphyton dynamics has been studied upon artificial substratum (microscopic glass slides) under various light conditions during the periods May–October 1986 and May–September 1987, in Lake Veluwe. Some additional observations on the periphyton development upon leaves of Potamogeton pectinatus L. have been made simultaneously. Four different light conditions were created in an experimental setup by manipulating the photon flux density through artificial shading.Periphyton upon artificial substratum exhibited a relatively high abundance with a distinct seasonal pattern. Periphyton accrual rates were highest at the beginning of June and in August and September upon slides which were incubated for two weeks. Periphyton mass increased during May and June, decreased or remained about the same during July and subsequently increased until an upper plateau was reached upon slides which were incubated from the beginning of May onwards.Generally, periphyton mass was lower upon slides than upon P. pectinatus. The seasonal variation in periphyton mass was more pronounced upon P. pectinatus leaves than upon the slides.Attenuation by periphyton upon slides ranged from 5 to 65% after two weeks of incubation. Periphyton upon slides which had been incubated for more than two weeks demonstrated an attenuation of more than 85%.Water quality parameters other than photon flux density were probably more important in determining the periphyton dynamics, since only minor differences were observed in periphyton mass between the various light conditions. Chlorophyll-a content was higher with increased shading on various sampling dates.Periphyton, especially older periphyton consisted largely of settled silt and clay particles and to a lesser extent of detrital matter on both substrata. Living epiphytes were only a relatively small fraction.It is concluded that a reduction of resuspension of sediment particles, giving less suspended matter in the water column, will result in lower periphytic mass. Consequently, the quantity of photosynthetically active radiation reaching the submerged macrophytes is expected to increase considerably.
Annual and perennial cyanobacterial mats from streams on Signy Island, Antarctica, show similar areal concentrations of chlorophyll-a and areal rates of photosynthesis. Maximum rates of photosynthesis were temperature dependant over the range 0–14 C, with a Q10 of approximately 2.5. Rates of photosynthesis per unit chlorophyll-a were comparable to other Antarctic mat communities but low compared to phytoplankton from upstream lakes. Areal rates of photosynthesis were however much higher than for phytoplankton. Low chlorophyll-specific rates of photosynthesis are interpreted as the effect of self shading within the mats. It is hypothesised that these mats rapidly attenuate incoming radiation and that photosynthesis in most of the mat is effectively light-limited. This situation is likely to occur in all thick periphyton films.
Eight different mathematical formulations of the photosynthesis-light curve for phytoplankton (up to and including light saturation) were recast in terms of the same two parameters : the initial slope CY, and the assimilation number P_M^B. Each equation was tested for its ability to describe empirical data from natural populations of marine phytoplankton: the results of 188 light-saturation experiments at three coastal locations in Nova Scotia over a 2-year period. The most consistently useful mathematical representation of the data was found to be the hyperbolic tangent function.
Thesis (Doctor of Philosophy)-Michigan State University. Bibliography : leaves 177-186.
The production of oxygen by algae during photosynthesis at steady state depends on irradiance according to a classical equation for the activity of enzymes inhibited by high concentrations of substrate. The equation is derived from a kinetic analysis of plausible reactions between photons and plant pigments, and it predicts that the inhibition of oxygenic photosynthesis often observed at full sunlight is an intrinsic property of these reactions. The equation contains three parameters, which are all sensitive to temperature. It provides a mechanistic basis for analysing adaptive responses of oxygenic photosynthesis, but a more complex theory will be required to account for the effect of irradiance on the assimilation of carbon during photosynthesis.
Primary production of epiphytic algae and phytoplankton in the littoral zone of Lake Kasumigaura
- N Takamura
- T Iwakuma
- M Aizaki
- M Yasuno
Takamura, N., T. Iwakuma, M. Aizaki & M. Yasuno, 1990. Primary production of epiphytic algae and phytoplankton in the littoral zone of Lake Kasumigaura. Mar. Microbiol. Food Webs 4: 239-255.
The role of algae in the littoral zone of a carp pond
- J P Komarkova
- Marvan
Symbols, units and conversion factors in studies of freshwater productivity
- G G Winberg
- G. G. Winberg
Artenzusammensetzung
- C Gätje
Physical determinants of phytoplankton succession
- C S Reynolds
Vergleichende Untersuchungen zur hydrochemischen Dynamik von Seen im schleswig-holsteinischen Jungmoränengebiet
- H E Müller
- H. E. Müller
Field experiments on shading effect by emergents on littoral phytoplankton and periphyton production
- M E Straskraba
- Pieczynska
Primary production and its dependence on the quantity of periphyton
- A W Szczepanski
- Szczepanska
- A. Szczepanski
Untersuchung über den Zusammenhang zwischen Produktion und Schilfdichte
- U Sommer
- U. Sommer
The effect of nitrogen supply on the PQ of natural planktonic assemblages
- R C T Raine
- R. C. T. Raine