Horizontal variation of biomass and C:N:P ratios of benthic algae in lakes

The horizontal variation of chlorophyll a (chl a) and C:N:P (carbon:nitrogen:phosphorus) ratio was estimated for benthic algal communities attached to living substrates (mussels and macrophytes) and to rocks and stones in three lakes of different trophy. Samples were taken in a nested hierarchical design with replicates separated by several cm, dm, 10 m, and km. The observed horizontal variation of chl a, C:N, and C:P ratios did not differ for horizontal scales, substrates, or lakes. Although the investigated lakes were quite unlike regarding nutrient status, light regime, or morphology, the patchiness was similar in all lakes. Moreover, patchiness was also similar on stones, macrophytes and mussels, although those substrates differed in longevity and surface structure. Similar patchiness regardless of scale, substrate, or sampled lake, implies the possibility of using an optimal sampling design calculated for one lake and substrate also in other lakes and on other substrates.     

Effects of acid wastes from titanium dioxide production on biomass and species richness of benthic algae

Titanium dioxide wastes are suspected to be toxic to rocky shore communities in an estuary in southeast Norway. An experimental project lasting two years examined whether titanium dioxide wastes affected recolonization by rocky shore organisms. The experiments were performed in situ in six tanks (each with 9 m³ brackish water) at two different levels of salinity. Three different concentrations of industrial waste water were used. The growth season in 1986 was dry and sunny compared to 1987, causing reduction of growth on exposed granite chips compared to controls. At the two highest waste concentrations in the tanks, Fucus serratus was observed with necrotic tissue both years, and in 1986 benthic diatoms were scarce.     

Responses of benthic algae to nutrient enrichment in a shallow lake: Linking community production,biomass, and composition

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Variation in distribution and biomass of marine benthic algae off Kulien, S Sweden

Samples of the macrobenthic flora were collected at 2, 4, 6, 8 and 10 m below mean water level at Kullen, S Sweden. The frequency, length, reproductive pattern and biomass of the commonest species, and the variations of these with depth and season are discussed. The species composition and the size of the plants indicate that the flora is strongly affected by the brackish environment. Only few species contributed substantially to the total mean biomass (100.1 g dry wt 0.25 m–2): Fucus Serratus (56%), Laminaria digitata (7%), L. saccharina (4%), Furcellaria lumbricalis (14%), the Phyllophora species (5%) and Chondrus crispus (3%). Species with thin filamentous or sheet–like thalli made up the remaining ca. 11%. The contribution made by this group increased with depth from 1% at 2 m to 48% at 10 m. The mean biomass at each depth was strongly correlated to the irradiance. The seasonal variation in biomass followed that of the irradiance but with a lag. In winter and late summer the growth was also influenced by temperature and nutrient concentrations. The total biomass is delimited by the low and fluctuating salinity in Öresund.     

The impact of substrate and lake trophy on the biomass and nutrient status of benthic algae

Algal biomass, C:N:P (carbon:nitrogen:phosphorus) ratios and APA (biomass specific alkaline phosphatase activity) were measured in benthic algal communities on living substrates (mussels and macrophytes) and on rocks and stones (epilithon) in three lakes of different trophy. Benthic algal communities on living substrates had lower C:N:P ratios than epilithon, whereas algal biomass was highest on rocks and stones. Benthic algal biomass increased with the trophic level of a lake despite an increase of C:N:P ratios in the benthic community. The differences in C:N:P ratios and algal biomass between lakes of different trophy were higher on inert substrates than on macrophytes and mussels, probably because algae on living substrates could compensate a poor nutrient supply from lake water with substrate nutrients. However, the substrate was not, as expected, the most important nutrient supply in the oligotrophic lake, but in the eutrophic lake. Therefore, differences between inert and living substrates in a single lake were highest in the eutrophic lake. APA values of the oligotrophic lake were very high especially for benthic algae on stones, indicating an ability of the community to take up nutrients from organic sources. In conclusion, living substrates were an important nutrient source for benthic algae and the importance of this nutrient supply did not decrease with increasing lake trophy.     

The effect of oxygen concentration on photosynthetic biomass production by algae

The effect of decreased oxygen concentration on photosynthetic biomass production was determined for Euglena gracilis Klebs strain z and Chlamydomonas reinhardtii Dangeard. At a constant carbon dioxide concentration of 0.03% (v/v), decreasing the oxygen concentration from 21% to 2% (v/v) gave a two-fold increase in dry-weight yield for E. gracilis; a result consistent with the operation of a functional glycollate pathway in this alga. A similar effect of oxygen concentration on dry-weight yield was not observed with C. reinhardtii.     

Periphyton in Lake Vechten,with emphasis on biomass and production of epiphytic algae

Summary Characteristics of the periphyton associated with the submerged macrophytesCeratophyllum, Elodea andMyriophyllum were similar. During the whole growing season the periphyton dry weight often exceeded that of the macrophyte. The periphyton contained much detritus and carbonates, and the epiphytic algae were accompanied by large numbers of bacteria, protozoans and rotifers. Attached algae were scarce, but motile diatoms were abundant throughout the year. Thus the periphyton showed the features of a benthic community. Consequently, the role of the macrophytes would be rather the extension of the bottom area instead of actively promoting the growth of microorganisms by providing minerals or excreting organic substances.During the peak of the littoral development the epiphytic algae expressed a high photosynthetic capacity, while at the same time the periphyton dark respiration was intense. After measurements of the depth distribution of biomass and light in aCeratophyllum stand, it was concluded that the contribution of the epiphytic algae to the production in the lake's littoral zone was substantial. Furthermore, on a daily basis, the total association of macrophytes and periphyton would be oxygen consuming due to heterotrophic activity, notably mineralization of the detritus.     

The distribution of benthic marine algae

Hitherto only gametangial and carposporangial phases of Thuretellopsis peggiana Kylin have been reported. A study of this rare member of the Dumontiaceae (Cryptonemiales) in culture has disclosed the existence of an encrusting tetrasporangial phase, previously unknown, whilst the life history has been shown to be of the ‘Bonnemaisonia’ type.     

Empirical relationships between profundal macroinvertebrate biomass and environmental variables in boreal lakes of Alberta, Canada

1. We empirically modelled profundal macroinvertebrate biomass (PMB) from collections of macroinvertebrates and a suite of trophic, water chemistry and morphometric variables from 26 lakes located within the Boreal Mixedwood and Boreal Subarctic ecoregions of Alberta, Canada.
2. Hypolimnetic dissolved oxygen (DO) concentrations (mg L⁻¹) explained 37% of the variance in PMB ((g m⁻²)^0.1) as a quadratic function, whereas water temperature (°C) explained 23% of variance in a linear relationship.
3. In contrast with other studies based on oligotrophic systems, indirect indicators of food availability (i.e. chlorophyll a and total phosphorus concentrations and Secchi depth) were not significant predictors of PMB in this study.
4. The predictive power of our models may be improved by obtaining more frequent (seasonal) estimates of PMB and hypolimnetic DO concentration and by quantifying biotic factors such as competition, predation, life history phenologies and recruitment success.     

Optimization of the biomass production of oil algae Chlorella minutissima UTEX2341

High production cost is a major obstacle to the extensive use of microalgae biodiesel. To cut the cost and achieve higher biomass productivity, Chlorella minutissima UTEX2341 was cultured under photoheterotrophic conditions. With the carbon, nitrogen and phosphorus concentration of 26.37, 2.61 and 0.03 g L?1 d?1 respectively, a maximum biomass productivity of 1.78 g L?1 d?1 was obtained, which was 59 times more than that cultured under autotrophic condition. The lipid productivity reached 0.29 g L?1 d?1, which was 11.9 times higher than the highest value reported by Oh et al. (2010). The conversion rate of microalgae lipids to FAME was found to be elevated from 45.65% to 62.97% and the FAME productivity increased from 1.16 to 180.68 mg L?1 d?1 after the optimization. 94% of the fatty acid of C. minutissima UTEX2341 was found to be composed of palmitic, oleic, linoleic and γ linoleic and the unsaturated fatty acids were the main parts (79.42%).     

Contribution of ciliated protozoa to the planktonic biomass in a series of Ontario lakes: quantitative estimates and dynamical relationships

The plankton of nine Ontario lakes spanning several physiographicregions was sampled every two weeks during the ice-free periodof 1981, and one lake was studied in the three previous years.Phytoplankton, zooplankton, and ciliated protozoa were sampled,counted and sized. The size data were converted to biomass estimatesto yield quantitative comparisons of the relative allocationof biomass among different functional compartments. This isthe first study to look simultaneously and quantitatively atthe total plankton system of lakes (including ciliates, pbytoplanktonand net zooplankton) over a broad physiographic region. Ciliatesconstitute –10% of the non-algal biomass and 5% of thetotal planktonic biomass of these lakes. Ciliate standing cropsamong lakes are significantly corrrelated with total organicand total inorganic carbon concentrations in the water column,while the dynamics of ciliate biomass fluctuations are significantlycorrelated with variations in total phosphorus concentration,in conductivity, in Kjeldahl nitrogen concentration, and ininorganic carbon content. There appears to be a significantdynamical relationship between ciliates as a proportion of thetotal planktonic biomass, exclusive of filamentous and large(>30 µm) spherical algae, and the relative biomassof small algae (2–5 µm) as a fraction of total algalbiomass, again exclusive of filaments and large (>30 µm)algae. The hypothesis is advanced that ciliates primarily functionas bacterial grazers in planktonic ecosystems and that theirprimary competitors in this role are rotifers.     

Global vegetation biomass production efficiency constrained by models and observations

Plants use only a fraction of their photosynthetically derived carbon for biomass production (BP). The biomass production efficiency (BPE), defined as the ratio of BP to photosynthesis, and its variation across and within vegetation types is poorly understood, which hinders our capacity to accurately estimate carbon turnover times and carbon sinks. Here, we present a new global estimation of BPE obtained by combining field measurements from 113 sites with 14 carbon cycle models. Our best estimate of global BPE is 0.41 ± 0.05, excluding cropland. The largest BPE is found in boreal forests (0.48 ± 0.06) and the lowest in tropical forests (0.40 ± 0.04). Carbon cycle models overestimate BPE, although models with carbon–nitrogen interactions tend to be more realistic. Using observation‐based estimates of global photosynthesis, we quantify the global BP of non‐cropland ecosystems of 41 ± 6 Pg C/year. This flux is less than net primary production as it does not contain carbon allocated to symbionts, used for exudates or volatile carbon compound emissions to the atmosphere. Our study reveals a positive bias of 24 ± 11% in the model‐estimated BP (10 of 14 models). When correcting models for this bias while leaving modeled carbon turnover times unchanged, we found that the global ecosystem carbon storage change during the last century is decreased by 67% (or 58 Pg C).     

Accumulation of dieldrin by benthic algae in laboratory streams

Summary The accumulation of dieldrin by benthic algal communities was studied in laboratory streams. Dieldrin concentrations ranging from 0.05 to 7.0 ppb were maintained in the water of laboratory streams for periods of two to four months. Analyses of algal samples by gas chromatography showed dieldrin concentrations ranging from 0.1 to 200 ppm. These results indicated that increases in concentration up to 30,000 times that of the water had occurred. Quantitative evaluation of species composition revealed that communities dominated by filamentous algae accumulated greater amounts of the insecticide than those in which unicellular diatoms were prevalent.

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Zusammenfassung Dieldrinanreicherung in Algenaufwüchsen in Laboratoriumsströmungen wurde untersucht. Dieldrinkonzentrationen zwischen 0.05 bis 7.0 Teilen/Milliarde wurden zwei bis vier Monate lang im Wasserstrom des Laboratoriums unterhalten. Gaschromatographische Analyse der Algenproben zeigte eine Dieldrinanreicherung zwischen 0.1 und 200 Teilen/Million. Diese Befunde entsprechen einer bis zu 30,000-fachen Konzentrationserhöhung in den Algen im Vergleich zu der Dieldrinkonzentration im Wasser. Quantitative Bewertung verschiedener Algenarten zeigte, da Kolonien, die vorwiegend aus filamentförmigen Algen bestanden, mehr Dieldin anreicherten als Kolonien, in denen einzellige Diatomalgen vorherrschten.

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This work is a contribution from the Pacific Cooperative Water Pollution Laboratories, Technical Paper No. 2611, Oregon Agricultural Experiment Station. The investigation was supported in part by research grant ES. 00040 from the Public Health Service.     

Distribution of multicellular benthic algae in an eutrophic ditch

Summary Eighty species of multicellular algae were observed in fifty-three samples, collected at six sampling stations in a ditch near the village of Tienhoven (The Netherlands) in August 1975. Most species seemed to prefer particular sampling stations above particular substrates. This preference was not observed with the algae, growing in floating and submerged algal masses. Average linkage cluster analyses from Sørensen similarity coefficients revealed a linear arrangement of the sampling stations reflecting the actual arrangement of the stations in the ditch.     

Effects of chronic bottom trawling disturbance on benthic biomass, production and size spectra in different habitats

Bottom trawling has widespread impacts on benthic communities and habitats. It is argued that the impact of chronic bottom trawling on benthic infauna depends on the natural disturbance levels to which benthic communities are adapted. We analysed biomass, production and size structure of two communities from a muddy and a sandy habitat, in relation to quantified gradients of trawling disturbance on real fishing grounds. We used an allometric relationship between body mass and individual production to biomass ratio to estimate community production. Chronic trawling had a negative impact on the biomass and production of benthic communities in the muddy habitat, while no impact was identified on benthic communities from the sandy habitat. These differences are the result of differences in size structure within the two communities that occur in response to increasing trawling disturbance.     

Growth of benthic freshwater algae on dairy manures

A potential alternative to land application of livestock manures for cropproduction is the production of algae to recover the nitrogen andphosphorus present in the manure. Compared to terrestrial plants,filamentous algae have exceedingly high growth and nutrient uptake rates. Moreover, they are capable of year-round growth in temperate climates,can be harvested on adapted farm-scale equipment, and yield a biomassthat should be valuable as an animal feed supplement. The objective of thisresearch was to evaluate algal turf scrubber (ATS) technology to removenitrogen, phosphorus and chemical oxygen demand from raw andanaerobically digested dairy manure. Laboratory-scale ATS units wereoperated by continuously recycling wastewater and adding manure effluentsdaily. ATS units were seeded with algal consortia from a nearby streamand grown using dairy manures from two different dairy farms. Algalbiomass was harvested weekly and dried prior to analysis for total Kjeldahlnitrogen, total phosphorus, and inorganic constituents. Wastewater sampleswere analyzed for total Kjeldahl nitrogen, ammonium, nitrate,orthophosphate, conductivity and chemical oxygen demand. Using atypical manure input containing 0.6–0.96 g total nitrogen day^-1,the dried algal yield was approximately 5 g m^-2 day^-1. Thedried algae contained approximately 1.5–2% phosphorus and 5–7%nitrogen. Algal nitrogen and phosphorus accounted for 42–100% ofinput ammonium-nitrogen (33–42% of total nitrogen) and 58–100%of input total phosphorus, respectively.