Periphyton Community Structure Research Articles

Periphyton development in three valley segments of a New Zealand grassland river: test of a habitat matrix conceptual model within a catchment

We monitored water nutrient concentrations, periphyton biomass, and periphyton cellular nutrient concentrations in run and riffle habitats at sites representative of headwater, mid-catchment and lowland valley segments of a grassland river for two years, and community composition on four occasions during this period, to determine how these communities varied spatially and temporally as a function of downstream changes in hydraulic conditions, flood disturbance regimes and enrichment. Predictions of community biomass and structure were tested under a proposed habitat matrix conceptual model for periphyton. Discharge increased and valley segment slope decreased in a downstream direction as expected from geomorphic models of catchment processes. However, site-specific depths and velocities did not change systematically down the river. Water nutrient concentrations suggested a change from nitrogen limitation of primary production at the headwater site to phosphorus limitation at the lowland site. This was associated with a downstream increase in stream nitrate concentrations, but not phosphorus. However, cellular nutrient concentrations and instream nutrient bioassays suggested either N limitation, or weak N and P limitation, at all sites. In runs, mean monthly chlorophyll-a did not vary significantly (P>0.05) among the three sites, but it did in riffles. The differences in community biomass between run and riffle habitats were more significant than differences among sites. Periphyton community structure in the runs was similar among valley segments during a period of frequent flood disturbances, but during a period of infrequent disturbances communities in the headwater sites were dominated by filamentous cyanobacteria whereas in the mid-catchment and lowland sites they were dominated by nitrogen-fixing cyanobacteria and diatoms. Major differences in community structure occurred in riffles among the sites. Riffle communities at the headwater site were dominated by filamentous cyanobacteria and diatoms, whereas at the mid-catchment and lowland sites filamentous green algae and diatoms were dominant, possibly a result of increased nitrate concentrations progressing downstream. Overall; a downstream gradient in nitrate enrichment appeared to control biomass and community composition of the riffle communities, but not the run communities. Strong grazer activity in runs during more hydrologically stable periods at the lowland site appeared to override any response to nutrients and maintained biomass at low levels. Periphyton biomass and community composition was predicted more accurately from the habitat matrix conceptual model based on local habitat factors than by expected downstream gradients in hydraulic conditions and enrichment.

Periphyton community structure and dynamics in a subarctic lake

Periphyton species composition was analysed at 20 stations around an island in a large (1239 km2) oligotrophic lake in subarctic Quebec (Lac à l'Eau Claire; latitude 56°10′N, longitude 74°30′W) to describe the mature communities colonizing the upper littoral region and to evaluate periphyton abundance and distribution relative to the physical environment. Four major communities could be clearly distinguished in the field by their macroscopic features, specifically colour (black, brown, and green) and growth form (filamentous or encrusted), as well as by their standing stock (cover and areal Chl a concentration) and photosynthetic characteristics. (1) Black crust—This community was dominated by the cyanobacterium Gloeocapsa, with highest percent cover in shallow waters (≤ 0.25 m) protected from wave action by offshore boulder barriers. Photosynthesis under full sunlight was low per unit biomass (0.7 μg C∙(μg Chl a)−1∙h−1). (2) Brown film—This community was dominated by Calothrix, with Gloeocapsa and Phormidium as subdominants. Maximum abundance was at 0.5 m, with photosynthetic rates that were similar to the black community. (3) Green crust—This community was dominated by the mucilaginous chlorophyte Gloeocystis, with Oscillatoria as subdominant, and colonized shallow depths (≤ 0.25 m) in the shaded underlayer of rocks. It had slow, light-limited photosynthetic rates (0.1 μg C∙(μg Chl a)−1∙h−1). (4) Green filaments—This community was dominated by Ulothrix zonata, with associated chlorophytes and diatoms, and was a rapidly growing assemblage characterized by the highest diversity, species richness, and productivity per unit biomass (3.5 μg C∙(μg Chl a)−1∙h−1). It occurred on gravel beds at depths < 0.5 m and was restricted to the well-illuminated south-facing shores of the island. Communities 1, 2, and 3 had similar maximum standing stocks throughout the period of sampling (mean of 1.3 μg Chl a∙cm−2), whereas the Ulothrix community rose from 1.9 μg Chl a∙cm−2 in late July to 5.5 μg Chl a∙cm−2 by mid-August. The overall rich biodiversity of the Lac à l'Eau Claire periphyton (> 200 taxa recorded) may reflect the diversity of microenvironments and intermediate disturbance in the upper littoral zone. Key words: cyanobacteria, chlorophytes, diatoms, epilithon, periphyton, photosynthesis.

An evaluation of periphyton community structure and function on tile and cobble substrata in experimental stream mesocosms

Periphyton communities are an ecologically important source of information when conducting experimental stream ecotoxicological studies. Experimental stream studies often utilize unreplicated systems in order to understand dose-response phenomena. The objective of this study was to examine the robustness of such a dose-response investigation. Autotrophic and heterotrophic periphyton were evaluated in replicated control experimental streams with open recruitment (once-through flow design). Measurements of population and community structure and community function over an eleven week colonization period were made on unglazed clay tile and cobble substrata. Several measures were significantly different during the study; however, most of these were a result of initial stochastic colonization events or associated with relatively rare algal populations. During the latter half of the study autotrophic and heterotrophic community measurements on tile and cobble substrata displayed similar trends in both control streams. Population and community metrics were significantly different for approximately 5% of the 400 measurements made after the initial sampling. These results strongly suggest that the driving forces behind structuring aquatic population and community responses will be test chemical exposure and not spuriously developed stream ecosystems with individual trajectories. Recruitment in these open systems is evenly distributed across the replicated experimental stream ecosystems.

Between-year variation of periphyton community structure in two Appalachian headwater streams

We used unglazed quarry tiles to survey periphyton community structure in two small Appalachian mountain streams from January through April in 1990, 1991, and 1992. Mean periphyton cell densities were greatest in 1990 (maximum of 1.3 × 108 cells cm−2), the year with the fewest periods of high discharge; cell densities were lowest in 1991 (maximum of 5.9 × 105 cells cm−2), the year characterized by the most periods of high discharge, and intermediate in 1992 (maximum of 2.1 × 106 cells cm−2). Mean cell densities of the dominant alga, the cyanophyte Chamaesiphon sp., followed this pattern, but some taxa of diatoms did not.

Periphyton Response to Longitudinal Nutrient Depletion in a Woodland Stream: Evidence of Upstream-Downstream Linkage

Longitudinal gradients in streamwater nutrient concentrations in Walker Branch are generated as a result of instream nutrient uptake and spatially confined groundwater inputs during the period from November to May. The response of the stream periphyton community to these longitudinal nutrient reductions was determined by measuring periphyton biomass, productivity, species composition, and phosphorus (P) cycling indices at four stations along a longitudinal transect in the stream. Phosphorus cycling indices (chlorophyll-specific phosphatase activity, phosphorus content of periphyton) exhibited significant changes along the longitudinal transect during those times of the year when streamwater soluble reactive phosphorus (SRP) concentrations also decreased along the transect. During the period from June to October, however, neither streamwater phosphorus concentrations nor phosphorus cycling characteristics exhibited longitudinal trends. Regressions between phosphatase activity and streamwater SRP concentration and between phosphorus content and streamwater SRP were highly significant for all data combined, with SRP explaining ≥74% of the variation in phosphatase activity and P content. Measures of periphyton biomass (chlorophyll a, total biovolume), and productivity (areal carbon fixation rate, chlorophyll-specific carbon fixation rate) exhibited no consistent longitudinal patterns, even during the period of longitudinal streamwater phosphorus depletion. Regressions between productivity measures and streamwater SRP concentration for all data combined were significant, but SRP explained ≤56% of the variation in productivity. Periphyton biomass and productivity at all stations along the longitudinal transect appear to be maintained at low levels by high and longitudinally uniform rates of herbivory throughout the year. Algal species composition exhibited some response to longitudinal nutrient depletion. The biovolume and percentage of the blue-green alga Chamaesiphon investiens increased and the percentage of the chlorophyte Stigeoclonium sp. declined longitudinally when nutrients also declined. Our results demonstrate an upstream-downstream biotic linkage in Walker Branch. We show that instream nutrient uptake can reduce the concentrations of nutrients in stream water and thereby influence the structure and functioning of downstream periphyton communities. However, increases in nutrient cycling in response to lower streamwater concentrations can partially compensate for nutrient depletion by upstream organisms, thereby buffering primary productivity in downstream periphyton communities from changes in nutrient supply.

RESPONSE OF PERIPHYTON COMMUNITIES TO CLAY AND PHOSPHATE LOADING IN A SHALLOW RESERVOIR1

ABSTRACTEnclosures in a small piedmont reservoir in the southeastern United States were used to determine the effects of loading by phosphate and two clay sediments on periphyton community structure and production during the summer growing season. The experimental design included replicated controls and the following treatments added at 2‐to 3‐day intervals: phosphate (PHOS), kaolinite (KAOL), montmorillonite (MONT), kaolinite with phosphate (K+P), and montmorillonite with phosphate (M+P). Periphyton were sampled from polyethylene strips of the same material as the enclosure walls, suspended at depths of 0.5 m and 2.0 m to assess treatment effects on shallow (epilimnetic) vs. deep (hypolimnetic) communities. Colonization after 40 days was sparse, dominated in biovolume by blue‐green algae in all but the epilimnion of controls, in which small gelatinous green algae and chrysophyte flagellates were abundant. The biovolume of shallow periphyton after 79 days was lowest in KAOL and MONT, intermediate in controls and PHOS, and greatest in clay + P. Hence, P enrichment alleviated the deleterious effects of clay on periphyton production, and clay + P appeared to act synergistically in stimulating benthic algal growth. Periphyton biovolume was comparable among shallow and deep controls, PHOS, and treatments with the rapidly settling kaolinite. Lowest biovolume occurred at depth in treatments with montmorillonite under extreme light attenuation imposed by the suspended, finely particulate clay. The relative contribution of blue‐green algae to total periphyton production was highest in clay + P treatments and lowest in controls. Heterotrophic dinoflagellates increased in the shallow periphyton under clay loading, and in the deep communities under PHOS and M + P. Periphyton contributed only 20–32% of total mesocosm productivity in controls, PHOS, and KAOL, increasing to about 40% in MONT, and to 72–91% of the total in M + P and K + P. The data indicate that benthic microalgae can represent a major proportion of the primary production in shallow reservoirs under high phosphate and sediment loading.

EFFECTS OF HERBIVORE SIZE AND HUNGER LEVEL ON PERIPHYTON COMMUNITIES1

ABSTRACTThe effects of herbivore size and hunger level were tested on lotic periphyton community structure and ash‐free dry mass (AFDM). My hypotheses were 1) that small herbivores would remove more periphyton per unit biomass than large herbivores of the same species because of energetic demands and 2) that within the same size class, starved herbivores would remove more periphyton than nonstarved herbivores. The herbivore used was the prosobranch snail Elimia clavaeformis Lea. Seven treatments were employed: 1) no snails (control); 2) small “starved” snails; 3) large “starved” snails; 4) small and large “starved” snails; 5) small fed snails; 6) large fed snails; and 7) small and large fed snails. Although snails removed significant amounts of periphyton AFDM relative to controls, neither snail size nor degree of starvation had a significant effect on loss of total AFDM. Small snails removed significantly more erect forms of Stigeoclonium tenue (C. A. Ag.) Kütz. than large snails, but snail size had no other significant effect. Starved snails removed significantly more Cocconeis placentula Ehr. than fed snails, suggesting that after the more susceptible growth forms (e.g. erect Stigeoclonium) were removed, Cocconeis cells became more vulnerable to grazing by hungry snails. When small and large snails were combined in chambers, large snails gained weight over time, whereas small snails lost weight. These results suggest that intraspecific competition may occur within populations of Elimia.

Validity of an Ecotoxicological Test System: Short-Term and Long-Term Effects of Arsenate on Marine Periphyton Communities in Laboratory Systems

Periphyton communities were established on glass substratum in the Gullmar Fjord (Sweden) and their sensitivity to arsenate was determined with short-term photosynthesis experiments. The study was done in May 1984 when phosphate levels were low. A 1-h exposure to arsenate gave IC20 (concentration required to inhibit photosynthesis by 20%) values of 0.4 μM. Communities established indoors in a flow-through aquaria system were substantially different from the fjord communities in terms of structure and biomass, although photosynthesis showed a similar sensitivity (IC20 = 0.6 μM). To explore the validity of this short-term ecotoxicological test system, we used a set of indoor, flow-through aquaria to study long-term effects (3 wk) on communities established under arsenate stress. Arsenate was added continuously at 0.1–10 μM above background levels (7 nM). Species composition as well as carbon, nitrogen, and chlorophyll a content of the communities were affected at 0.2–0.8 μM (IC20). This is in good agreement with the sensitivity of the short-term test. We conclude that inhibition of the physiological parameter photosynthesis is relevant information for the understanding of ecological events caused by arsenate stress in the periphyton communities. At least for effects of arsenate, the short-term metabolic test system can be used for valid predictions of gross changes in periphyton community structure and production. Comparison with arsenic levels in polluted coastal areas of Sweden lead to the conclusion that periphyton communities may be affected, particularly when phosphorus levels are low.

The use of periphyton communities for nutrient removal from polluted streams

The results of experiments on the efficiency of periphyton communities for nutrient removal from polluted streams in a continuous flow-through are given. The artifical stream (5 m × 0.7 m × 0.5 m) was made of wood, with silon (a kind of nylon) screens, as a substratum for periphyton growth. The elimination of nutrients was monitored by ammonium, nitrite, nitrate and orthophosphate analyses. In addition, the elimination of organics and the decrease in trophic state were determined. During two field experiments a marked elimination of nitrogen and phosphorus was demonstrated. The maximum efficiency of ammonium and orthophosphate removal was 80% and 70%, respectively. Organic removal reached 35% (C.O.D.Mn-Kubel) and 54% (B.O.D.5). Inorganic and organic nutrient elimination caused significant changes in periphyton community structure in the outflow portion of the through, evaluated by the saprobic index and the similarity coefficient. The experiments confirmed that periphyton communities are a useful means of nutrient removal from polluted streams.

Effect of Grazing by Physa integra on Periphyton Community Structure

Experiments were conducted in a small northern Michigan lake to assess the effects of grazing by the snail Physa integra on periphyton communities. Periphyton was allowed to colonize glass microscope slides in enclosures for 26 d prior to the introduction of snails at three densities. Snails were allowed to graze for 21 d before the periphyton was collected and analyzed. Physa integra significantly reduced the biovolume, species richness, and diversity of periphyton. Diatoms were relatively more abundant and green algae relatively less abundant at low grazer densities when compared with controls and periphyton at high grazer densities. Grazers reduced the physiognomic diversity of periphyton which led to a community dominated by prostrate diatoms. Seventeen algal taxa were significantly reduced in relative abundance by grazers. Synedra and Mougeotia were the most abundant taxa of this group. Eunotia pectinalis var. minor, a prostrate chain-forming diatom, was least affected by grazing and experienced a si...

EFFECTS OF DISTURBANCE ON EPIPHYTIC COMMUNITY ARCHITECTURE1

ABSTRACT Microdistributional patterns of attached algal communities on Cladophora and glass slides were compared under varying disturbance regimes in the Upper Mississippi River, using light and scanning electron microscopy. Localized physical disturbance, induced by boat traffic and wind‐generated wave action in the main channel, inhibited development of complex attached algal communities and maintained an adnate flora with two‐dimensional architecture. In contrast, communities protected from disturbance developed a more complex, three‐dimensional architecture. A high degree of architectural similarity was observed between communities on Cladophora and glass substrates exposed to similar levels of disturbance. Communities exposed to severe disturbance resembled ones in early stages of colonization and development, whereas less disturbed communities were similar to ones in advanced stages of development. These results demonstrated that turbulence strongly influences the community structure of periphyton on both micro and macro scale levels.

Effects of subacute cadmium exposure on a hardwater mountain stream microcosm

Open stream microcosms in the RIFFLE facility were exposed to 22 μg l −1 cadmium for 21 days. Although less than 0.3% of the metal passing through the streams remained in the microcosms, more than 1000 μg g −1 dry wt accumulated in the Aufwuchs community, apparently in response to photosynthetically induced CdCO 3 precipitation. Accumulation decreased with increasing trophic level in the order: Aufwuchs > macrophytes > grazers/collectors > predators. Although no effect on periphyton community structure was observed, invertebrate grazers and collectors in the riffles were adversely affected by cadmium exposure, while populations of pool chronomida and riffle predators increased. Open lotic microcosms are shown to provide valuable hypotheses regarding metal fate and effects, but cannot be used as simple screening tools because of the nature of the invertebrate population data likely to be produced.

A comparison of algal periphyton composition on eleven species of submerged macrophytes

The composition of algal periphyton was examined on eleven species of submerged macrophytes collected at a depth of 0.25 m in Sewell Lake, southwestern Manitoba, a shallow nitrogen and phosphorus rich lake. There were substantial differences in the periphyton on all macrophyte species. Diatom subcommunities were the most similar, while the green algal subcommunities were the most dissimilar on different plant hosts.Potamogeton zosteriformis differed the most from all other macrophytes with respect to the composition of its periphyton. These results and a comparison of the literature suggest that the composition and structure of periphyton communities on living substrates is a product of the interaction of many variables, determined by the characteristics of the host plant, the external environment and the algae themselves. Studies of periphyton at a given site must take into account the various substrates available.

The effect of terrestrial herbicides on the community structure of stream periphyton

The influence of 0·1, 1 and 10 mg kg −1 of the terrestrial herbicides atrazine, trifluralin, MSMA and paraquat on the species composition and standing crop of algal periphyton was assessed using artificial streams. For each herbicide, two experiments were performed: one using algae from a pristine spring and another using algae from a stream heavily influenced by agricultural runoff. Also, in each experiment, 0·01 mg kg −1 of the test herbicide was maintained in the water of half the streams during a three-week period prior to the application of the 0·1/1/10 mg kg −1 treatments in an attempt to induce development of a resistant community. Atrazine caused the most extensive damage. Rhopalodia, Phormidium and Cladophora were severely inhibited by 1 and 10 mg kg −1, and these treatments caused a large biomass reduction. Trifluralin decomposed rapidly in the streams and had no toxic effect. MSMA and paraquat caused reductions in several filamentous cyanobacteria, but these effects were less serious than those of atrazine. Contrary to expectation, the spring community seemed more resistant than the stream community to both atrazine and paraquat. Also, while the 0·01 mg kg −1 treatment caused detectable reductions in several species, there was no evidence that it induced resistance to any of the herbicides.

Periphyton grazing byAmnicolalimosa:An enclosure-exclosure experiment

Abstract An enclosure-exclosure experiment was performed in Nonquit Pond, Rhode Island to test the effect of grazing by Amnicola limosa (Say) (Gastropoda) upon lentic periphyton. Periphyton from enclosures with A. limosa had higher organic content in May and July, and lower standing crops in May, July, August, and September than periphyton from exclosures without A. limosa. Small diatom (< 18 μm long, other than Cocconeis placentula) abundances on glass slides were significantly lower in the enclosures than in the exclosures. Cocconeis abundances were not significantly affected by grazing. Cocconeis relative abundances on glass slides exposed in the littoral zone of Nonquit Pond also increased with increased grazing pressure from A. limosa. Because characteristics of Nonquit Pond do not seem to be unusual, and grazer abundances were not extreme, these data may have general importance to the study of lentic periphyton community structure.

A preliminary investigation of the effect of current speed on periphyton community structure

A preliminary investigation of the effect of current speed on periphyton community structure

The dynamics and structure of periphyton communities in three Cascade Mountain streams

The dynamics and structure of periphyton communities in three Cascade Mountain streams

Changes in Periphyton Community Structure Following Diatom Inhibition

Germanium dioxide, a compound which selectively inhibits silicon incorporation in diatoms, was added to biologically inert acrylamide gel, and coated on microscope slides. These slides were immersed about 50 cm below the surface of three temperate lakes in different parts of the world. Periphyton succession in the presence of germanium differed from that on germanium-free controls. The selective inhibition of diatoms resulted in significantly lower densities of some non-silicious species while other algae increased their density above that of control slides. Germanium treated slides had significantly lower standing crop and species diversity than control slides. Results are discussed in relation to general principles governing community structure.

The Effects of Grazing by Snails on Community Structure of Periphyton in Laboratory Streams

The effects of grazing by snails on community structure of periphyton were studied in laboratory streams. The levels of grazing studied caused slight reduction in standing crop, significant increase in chlorophyll a concentration, reduction in pigment diversity and no effect on species diversity. Grazing did not affect instantaneous rates of accumulation of oven-dry weight, ash-free weight, or ash-free percentage of oven-dry weight. Pigment diversity and species diversity were positively correlated. Oven-dry weight per unit chlorophyll a was reduced by grazing, but ash-free weight per unit chlorophyll a was not affected. Grazing had no effect on the percentage of chlorophyll a in ash-free weight.

A quantitative method for assessing the toxic effects of some water soluble substances, based on changes in periphyton community structure

Abstract A method to assess the potential damage of a particular water soluble compound when released in lakes and streams is described. The results of a test using germanium dioxide which has a known effect, provided evidence that quantitative changes in the species composition of the colonizing periphyton community reflect the nature of the toxicant to which they were exposed. Natural diatom growth in the presence of germanium was inhibited and the ensueing changes in the species composition of the treated community were reflected in changes in the index of diversity calculated for that community. The advantages and disadvantages of this approach are discussed.