Periphyton Dynamics Research Articles

Effects of hydrologic and water quality drivers on periphyton dynamics in the southern Everglades

Everglades periphyton mats are tightly-coupled autotrophic (algae and cyanobacteria) and heterotrophic (eubacteria, fungi and microinvertebrates) microbial assemblages. We investigated the effect of water column total phosphorus and nitrogen concentrations, water depth and hydroperiod on periphyton of net production, respiration, nutrient content, and biomass. Our study sites were located along four transects that extended southward with freshwater sheetflow through sawgrass-dominated marsh. The water source for two of the transects were canal-driven and anchored at canal inputs. The two other transects were rain-driven (ombrotrophic) and began in sawgrass-dominated marsh. Periphyton dynamics were examined for upstream and downstream effects within and across the four transects. Although all study sites were characterized as short hydroperiod and phosphorus-limited oligotrophic, they represent gradients of hydrologic regime, water source and water quality of the southern Everglades. Average periphyton net production of 1.08 mg C AFDW−1 h−1 and periphyton whole system respiration of 0.38 mg C AFDW−1 h−1 rates were net autotrophic. Biomass was generally highest at ombrotrophic sites and sites downstream of canal inputs. Mean biomass over all our study sites was high, 1517.30 g AFDW m−2. Periphyton was phosphorus-limited. Average periphyton total phosphorus content was 137.15 μg P g−1 and average periphyton total N:P ratio was 192:1. Periphyton N:P was a sensitive indicator of water source. Even at extremely low mean water total phosphorus concentrations ( ≤ 0.21 μmol l−1), we found canal source effects on periphyton dynamics at sites adjacent to canal inputs, but not downstream of inflows. These canal source effects were most pronounced at the onset of wet season with initial rewetting. Spatial and temporal variability in periphyton dynamics could not solely be ascribed to water quality, but was often associated with both hydrology and water source.

THE SCALE TRANSITION: SCALING UP POPULATION DYNAMICS WITH FIELD DATA

Applying the recent developments of scale transition theory, we demonstrate a systematic approach to the problem of scaling up local scale interactions to regional scale dynamics with field data. Dynamics on larger spatial scales differ from the predictions of local dynamics alone because of an interaction between nonlinearity in population dynamics at the local scale and spatial variation in density and environmental factors over the regional population. Our systematic approach to scaling up involves the following five steps. First, define a model for dynamics on the local spatial scale. Second, apply scale transition theory to identify key interactions between nonlinearity and spatial variation that translate local dynamics to the regional scale. Third, measure local-scale model parameters to determine nonlinearities at local scales. Fourth, measure spatial variation. Finally, combine nonlinearity and variation measures to obtain the scale transition. Using field data for the dynamics of grazers and periphyton in a freshwater stream, we show that scale transition terms greatly reduce the growth and equilibrium density of the periphyton population at the stream scale compared to rock scale populations, confirming the importance of spatial mechanisms to stream-scale dynamics.

Integrated Hydrodynamic and Water Quality Modeling System to Support Nutrient Total Maximum Daily Load Development for Wissahickon Creek, Pennsylvania

This paper presents a hydrodynamic and water quality modeling system for Wissahickon Creek, Pa. Past data show that high nutrient levels in Wissahickon Creek were linked to large diurnal fluctuations in oxygen concentration, which combining with the deoxygenation effect of carbonaceous biological oxygen demand CBOD causes violations of dissolved oxygen DO standards. To obtain quantitative knowledge about the cause of the DO impairment, an integrated modeling system was developed based on a linked environmental fluid dynamics code EFDC and water quality simulation program for eutrophication WASP/EUTRO5 modeling frame- work. The EFDC was used to simulate hydrodynamic and temperature in the stream, and the resulting flow information were incorporated into the WASP/EUTRO5 to simulate the fate and transport of nutrients, CBOD, algae, and DO. The standard WASP/EUTRO5 model was enhanced to include a periphyton dynamics module and a diurnal DO simulation module to better represent the prototype. The integrated modeling framework was applied to simulate the creek for a low flow period when monitoring data are available, and the results indicate that the model is a reasonable numerical representation of the prototype.

Seasonal Dynamics of Periphyton in a Large Tropical Lake

Tropical aquatic systems are generally assumed to have little seasonality in productivity patterns. However, this study indicated that there was substantial seasonal variation in epilithic productivity and biomass in tropical Lake Tanganyika, due primarily to seasonal patterns in lake hydrodynamics that influence nutrient availability. Although they support much of the lake’s biological diversity, epilithic algae made a minor contribution to the total energy budget in Lake Tanganyika. A comparison among large, oligotrophic lakes revealed no significant latitudinal trends in periphyton productivity or biomass. However, Lake Tanganyika has relatively low benthic algal biomass and is therefore more efficient at photosynthesis than the temperate lakes. The influence of wave action and consumer density and diversity may be important in moderating productivity of the epilithic community.

Modifications of WASP for Simulating Periphyton Dynamics, Sediment Oxygen Demand and Other Enhancements

Modifications of WASP for Simulating Periphyton Dynamics, Sediment Oxygen Demand and Other EnhancementsThe Water Quality Analysis Simulation Program (WASP6) is routinely used throughout the United States and World as a tool for managing water quality. WASP has a long history of development and application; it continues to be enhanced today to tackle some of the more complex issues associated with Total Maximum Daily Load (TMDL) development. This paper provides an overview of some of the...Author(s)Tim A. WoolJames L. MartinSteven R. DavieSourceProceedings of the Water Environment FederationSubjectSession 1 Models for TMDLsDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2003ISSN1938-6478SICI1938-6478(20030101)2003:4L.45;1-DOI10.2175/193864703784828354Volume / Issue2003 / 4Content sourceTMDLS ConferenceFirst / last page(s)45 - 52Copyright2003Word count100

Macrophyte and periphyton dynamics in a UK Cretaceous Chalk stream: the river Kennet, a tributary of the Thames.

An initial study to observe the seasonal trends and to determine the factors influencing macrophyte and periphyton growth patterns was undertaken on a representative reach of the River Kennet (UK) over a 2-year period (1998-2000). Maximum average macrophyte and average periphyton dry matter biomass recorded during the growing season were 200 and 21 g m(-2), respectively. The relationships between macrophyte and periphyton percentage cover and biomass data with physico-chemical variables were investigated. Regression analysis indicated that of the parameters measured, flow, and in the case of the dominant Ranunculus spp., solar radiation, were best able to predict macrophyte biomass and cover. The periphytic biomass within the reach was low, possibly as a result of relatively high flows and low phosphorus concentrations following the introduction of effluent treatment at the sewage works immediately upstream of the reach. Periphytic biomass was poorly correlated with the physical variables measured. This indicates that biomass is regulated by complex interactions between the physical and chemical factors, such as flow, solar radiation and phosphorus concentration. These interrelationships require further investigation.

Dynamics of periphyton during a summer low water period in relation to anthropic levels and the morphology of a French river: the Garonne

Dynamics of periphyton during a summer low water period in relation to anthropic levels and the morphology of a French river: the Garonne

A model of the development of a periphyton community: resource and flow dynamics

An ecological model of periphyton dynamics was designed to approach the development of a periphyton community under the effects of surrounding nutrient concentration and light intensity. The model simulated the vertical heterogeneities of biomass, light irradiance, and nutrients within the periphyton mat. To determine the competition for resources between species, a Monod-type relationship was used to relate external nutrient concentration to periphyton uptake rate, and ‘Liebig's law of the minimum’ was used to combine light and nutrient effects on growth rate and tension strength of the algal cell. The effect of the periphyton community to the vertical distribution of water velocity was also numerically investigated. To confirm the validities, the developed model was verified using several cases: the external concentration was constant or was varied with different diffusion coefficients. Reasonable responses of the periphyton community to the ambience nutrient concentrations, light intensity and, in turn, temporal variation of nutrients during the development of a periphyton community strongly encouraged further application of the model. Variation in the water velocity in a vertical direction intensively contributed to the results of the model.

Spatial structure and populations of a periphyton community: a model and verification

An ecological model of periphyton dynamics was designed to simulate the development of periphyton communities. From morphological differences in the growth patterns of filamentous and non-filamentous algae, the model simulated the vertical structure of a periphyton mat. The effects of shear stress on the colonization and the detachment process, and the overall response of the community to water flow were formulated. Provided that nutrients were sufficient for periphyton growth, a light index, representing the light availability for photosynthesis, was assumed to indicate not only the reproduction ability of an algal cell, but also the tensional strength of a cell against the drag force. The thickness of the periphyton mat, which determines dynamically the light attenuation in the periphyton mat, was also evaluated. The model was verified with three cases. First, without detachment of periphyton community, the process of growing mat was addressed under a constant light index, and thus a constant reproduction rate. The vertical structure of the periphyton community was simulated using different light indexes. Second, the growth rate and vertical light distribution inside the periphyton mat were simulated with three values of the biotic light attenuation coefficient. Third, the time of detachment, detachment effects on community growth, etc., were investigated at three different water velocities: 10, 20, and 30 cm s −1. Finally, the model was applied to experimental results in a stream, successfully reproducing the important characteristics observed in the experiment of the succession of communities, such as the variation of filamentous and non-filamentous cell densities related to the light distribution and the detachment of filamentous species.

Periphyton Dynamics in a Subalpine Mountain Stream during Winter

Periphyton Dynamics in a Subalpine Mountain Stream during Winter

Periphyton Dynamics in a Subalpine Mountain Stream during Winter

We conducted two experiments to determine the activity of and factors which control periphyton during winter in Stevensville Brook, Vermont. The first experiment during winter/spring 1994 examined the effect of a 300 to 450% difference in light and doubling of flow (low and high light, slow and fast flow) on periphyton chlorophyll a (chl a) and ash-free dry mass (AFDM) from stream rocks and artificial substrata. A second experiment was performed to determine whether periphyton was nitrogen or phosphorus limited. In addition, stream water was sampled during fall/winter 1994/95 for nitrate (NO3), ammonia (NH4), soluble reactive phosphorus (SRP), and total phosphorus (TP) to determine the availability of nutrients in Stevensville Brook. Increases of up to 250% for AFDM and 600% for chl a during the first study indicated robust activity throughout the winter despite low temperatures and light. Flow had a negative effect and sampling date was found to have a significant effect on periphyton biomass (chl a and AFDM) while light was found to influence increases in AFDM on clay tiles only. Water analyses showed that SRP was less than 0.001 mg L−1, NH4 and TP were low and often undetectable, and NO3 remained at about 0.20 mg L−1. Results from the nutrient enrichment experiment showed a significant response of chl a to P but not N and no response of AFDM to enrichment with either N or P. In Stevensville Brook during winter, the algal community, as represented by the chl a concentration, is predominantly controlled by phosphorus concentrations and is influenced to a lesser extent by flow; the periphyton community as a whole, represented by AFDM, is controlled mostly by stream flow and light.

Periphyton biomass on Echinochloa polystachya (H.B.K.) Hitch. of a lake of the Lower Paraná River floodplain, Argentina

Spatial and temporal variation of periphyton biomass on Echinochloa polystachya (H.B.K.) Hitch. was studied monthly in a turbid lake of the Lower Parana River floodplain from May 1995 to May 1996. Measures of chlorophyll a, dry weight and ash free dry weight were obtained from material scraped off the stems of the plant. Two sampling sites with different macrophyte cover were selected: Montiel (littoral area of lake Montiel) and Ciego (littoral area of a vegetated environment connected to the lake). Physical and chemical variables were measured at each sampling site in order to characterize the environments. The sampling sites differed: Montiel appeared influenced by inputs from the Parana River, while Ciego was less affected due to the effect of the macrophytes. The influence of the substrata on the periphyton dynamics was evident at both sampling sites. The values of periphytic biomass variables were lower at Ciego station where macrophyte development was more important. Multiple regression analyses performed with the different biomass variables, revealed that a combination of physical-chemical variables could explain the variability of the biomass, both at Ciego and Montiel, confirming that it is difficult to detect a single factor affecting the periphytic community in natural systems.

Modelling periphyton dynamics in running water

The short-term biomass dynamics of periphyton communities in running water is characterized by deep variations. This temporal variability is mainly produced by changes in running water velocity. The shear force caused by the friction of water over the surface of the periphyton produces a removal of biomass and creates open sites for colonization. Running water also brings new suspended algae that can establish on open sites. An increase in the velocity of the water can also improve the renewal of nutrients in depleted areas and the elimination of waste products, producing higher reproductive rates. In this paper, we have developed a model of periphyton biomass dynamics taking the water velocity and nutrient concentration as external driving variables influencing immigration, removal and reproductive rate of the algae. We fitted the model to field data encompassing high and low water velocities and different seasons. We have qualitatively compared the parameters obtained from different situations with the expected ones based on bibliographic information. The model has shown a good fit to field data and parameters were similar to expected ones, giving evidence that the model provides a good description for the processes that dominate the periphyton dynamics in running waters.

Periphyton dynamics in a floodprone prealpine river: evaluation of significant processes by modelling

1. Periphyton chlorophyll a was measured at weekly or 2 weekly intervals from October 1992 to March 1994 at four sites in a Swiss prealpine gravel bed river that was frequently disturbed by unpredictable spates.2. To evaluate the dominant processes that control periphyton biomass, measured data were compared with a set of simulations from an empirical dynamic periphyton model. Different combinations of process hypotheses were systematically activated and deactivated in order to assess their importance.3. The simplest model leading to an acceptable agreement with measured data employs a biomass‐dependent growth rate, a detachment rate directly proportional to discharge and biomass, and a catastrophic loss rate during bed moving spates. Terms describing light or temperature dependence had a minor effect on the model fit.4. The model describes the temporal pattern of the periphyton biomass as a series of growth curves periodically truncated by spates. Within the uncertainties of the measurements, mainly caused by the spatial heterogeneity of periphyton, the biomass recovered along deterministic trajectories.5. Sensitivity analyses with respect to model parameters and model structure showed that site‐specific model parameters could not be unequivocally determined, and that the model yields similar results with slightly different formulations of processes. This indicates that the data base with respect to periphyton biomass was too small for a unique identification of model details but that the main conclusions on the significance of processes did not depend on arbitrary choices of the model formulation.

Seasonal dynamics of epilithic periphyton in oligotrophic Lake Taupo, New Zealand

Abstract The biomass and species composition of epilithic periphyton in oligotrophic Lake Taupo was measured over a full year. Measurements of photosynthetic carbon uptake were made during summer and early winter. The lake supported a high biomass of epilithic periphyton throughout the year, averaging 100–600 mg m‐ 2 over the 0–35 m water depth and peaking in early summer. Periphyton extended to at least 40 m depth. Depth‐integrated carbon fixation rates of 242–362 mg m‐2 h‐1 were measured. Periphyton constituted more than 90% of the algal biomass and carbon fixation within the littoral zone, but less than 2% of production on a whole‐lake basis. Based on taxonomic composition, periphyton could be divided into three zones, surface (0–2 m), mid water (2–20 m) and deep (> 20 m). The diatoms Aulacosira granulata, Rhopalodia novae zealandiae, Epithemia sorex, and Fragilaria spp. dominated the deep assemblage, Tolypothrix tenuis and Mastogloia elliptica the mid water, and Scytonema, Dichothrix, and filamentous ...

河床付着生物膜現存量の周年変化シミュレーション

In the Hinuma River, changes of periphyton biomass were observed weekly from September 1987 to March 1990 and compared with a model simulation to evaluate the dynamics of periphyton biomass.A model was developed for simulating the periphyton biomass in a river system. The model consists of two sub-models : growth and scouring models. Parameters of the growth model were estimated based on the daily observation for a two-week period in each season. The change of the periphyton biomass was compared with that calculated through the model. Reasonably close agreement was found between the observed and calculated biomass ; however, a significant deviation was observed for the winter seasons when the biomass loss did not occur through scouring due to storm events. This deviation may be caused by significant detachment of the periphyton biomass and intensive grazing by benthic animals during the winter seasons.The annual growth of periphyton biomass and the annual periphyton biomass scoured were found to be 110 g·m-2 and 80 g·m-2 as carbon, respectively. The periphyton communities may absorb dissolved nitrogen and phosphorus from river water for their growth. If this is case, in the Hinuma River, at 10-km downstream, 0.6% and 6.7% of the dissolved nitrogen and phosphorus in terms of the annual runoff loading may be utilized by the periphyton, respectively.

Dynamics and attenuation characteristics of periphyton upon artificial substratum under various light conditions and some additional observations on periphyton upon Potamogeton pectinatus L.

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.

A Hierarchical Model of Lotic Ecosystems

This paper presents the structure and properties of a total stream model that simulates the dynamics of small, flowing—water ecosystems in the northwestern United States. Conceptually, the model is hierarchically structured, consisting of 7 basic processes: periphyton dynamics, grazing, shredding, collecting, invertebrate predation, vertebrate predation, and detrital conditioning. These processes are subprocesses of 3 echelons of higher level processes: detritivory; herbivory; primary consumption; predation; and the total ecosystem. The model has 14 state variables in the 7 basic processes, and is conceptualized in discrete time with a basic time step corresponding to 1 day. Behavior of the stream model relative to different schedules of energy inputs and to the practice of clear—cut logging was investigated and related to contemporary theory of lotic ecosystems. In general, model behavior indicated that the regulation of biological processes in streams is complex, the mechanisms of which vary seasonally and from process to process. If a process is regulated by food supply, its annual production tends to increase as predation increases, while mean biomass may or may not be affected appreciably. In contrast, an increase in predation tends to decrease both mean biomass and annual production in processes regulated primarily by predation and such life history phenomena as insects emergence. The stream model provided the stimulus that led to a mathematical expression for the rate of production at the level of the entire ecosystem, and model behavior suggests that this rate tends to remain constant along a continuum from small, first—order streams with no tributaries to larger rivers which eventually drain into the sea.

Periphyton Dynamics in Laboratory Streams: A Simulation Model and Its Implications

A simple and an expanded model of periphyton dynamics in lotic environments are described. The simple model includes one level variable, the biomass of the periphyton assemblage, and four rate variables: primary production, community respiration, and two export fractions. In the expanded model three level variables and eight rate variables are added to the simple model to introduce the effects of allochthonous organic matter and grazing activities by an aquatic snail. In general, computer output from the expanded model supports the hypothesis that the relatively low biomasses of periphyton observed in the small streams of western Oregon are the result of grazing activities by aquatic animals, high silt loads during the fall and winter months, and the effects of a dense canopy of terrestrial vegetation on light penetration. Furthermore, the model indicates that it is bioenergetically feasible for a periphyton biomass of about 10 g m—2 ash—free dry weight to support a consumer biomass of 150 g m—2 or more if the productive capacity of the system is sufficient. The simulation models provided an analytical way of synthesizing the results of a number of experiments with periphyton assemblages, identified weaknesses in the experimental data, and provided insights into the dynamics of periphyton assemblages that could not be obtained by intuition alone or by examining the results of individual experiments.