نتایج جستجو برای: periphyton

تعداد نتایج: 659  

2014
Stephanie J. McCall Michael J. Bowes Tanya A. Warnaars Michelle S. Hale James T. Smith Alan Warwick Cyril Barrett

Reducing phosphorus (P) loading to rivers is seen as a key mitigation measure to improve aquatic ecology and control excessive algal growth, as P is widely assumed to be the limiting nutrient in most rivers. Nutrient enrichment experiments using within-river flume mesocosms were conducted in the oligotrophic River Rede, to determine how periphyton accrual was affected by increasing P concentrat...

2015
Kemal Sanli Johan Bengtsson-Palme R. Henrik Nilsson Erik Kristiansson Magnus Alm Rosenblad Hans Blanck Karl M. Eriksson

Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans, and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communit...

2014
Jūratė Lesutienė Elena Gorokhova Daiva Stankevičienė Eva Bergman Larry Greenberg

Periphyton communities of a boreal stream were exposed to different light and nutrient levels to estimate energy transfer efficiency from primary to secondary producers using labeling with inorganic (13)C. In a one-day field experiment, periphyton grown in fast-flow conditions and dominated by opportunistic green algae were exposed to light levels corresponding to sub-saturating (forest shade) ...

2011
Rafael D. Guariento Luciana S. Carneiro Adriano Caliman João J. F. Leal Reinaldo L. Bozelli Francisco A. Esteves

Understanding the effects of predators and resources on primary producers has been a major focus of interest in ecology. Within this context, the trophic cascade concept especially concerning the pelagic zone of lakes has been the focus of the majority of these studies. However, littoral food webs could be especially interesting because base trophic levels may be strongly regulated by consumers...

2015
Beth C. Norman Marguerite A. Xenopoulos Daniel Braun Paul C. Frost Amitava Mukherjee

Exposure to silver nanoparticles (AgNPs) may alter the structure and function of freshwater ecosystems. However, there remains a paucity of studies investigating the effects of AgNP exposure on freshwater communities in the natural environment where interactions with the ambient environment may modify AgNP toxicity. We used nutrient diffusing substrates to determine the interactive effects of A...

2001
B. HIGLEY H. J. CARRICK M. T. BRETT C. LUECKE C. R. GOLDMAN

Rising levels of ultraviolet radiation (UVR) striking the Earth’s surface have led to numerous studies assessing its inhibitory effects on phytoplankton and periphyton in aquatic systems. Mineral nutrients such as nitrogen (N) and phosphorus (P) have been shown to increase aspects of algal metabolism and compensate for UVR inhibition. An in situ substratum enrichment technique and UV shielding ...

2018
Madlen Gerke Daniel Cob Chaves Marc Richter Daniela Mewes Jörg Schneider Dirk Hübner Carola Winkelmann

Benthic grazing strongly controls periphyton biomass. The question therefore arises whether benthic grazing could be used as a tool to reduce excessive growth of periphyton in nutrient-enriched rivers. Although benthic invertebrate grazers reduce the growth of periphyton, this is highly context dependent. Here we assessed whether the only obligate herbivorous fish in European rivers, the common...

1999

The vulnerability of periphyton and grazers to current and future levels of ultraviolet radiation (UV) has important ramifications for energy flow in shallow waters. We reduced ambient UV levels in a Tennessee stream with UVopaque Plexiglas suspended over the stream and compared periphyton under these Plexiglas filters to periphyton under UV-transparent polyvinylidene film. The experiments were...

2007
John S. Kominoski Paul A. Moore Robert G. Wetzel Nancy C. Tuchman

Elevated atmospheric CO2 increases plant C fixation, and much of the soluble C content of deciduous leaf litter entering streams is leached as dissolved organic C (DOC). The effects of DOC from trembling aspen (Populus tremuloides Michaux) leaf litter grown under elevated (ELEV 1⁄4 720 ppm) and ambient (AMB1⁄4 360 ppm) CO2 on stream periphyton were measured during a 35-d experiment in outdoor a...

2011
TYLER J. KOHLER JUSTIN N. MURDOCK KEITH B. GIDO WALTER K. DODDS

1. Anthropogenic activities in prairie streams are increasing nutrient inputs and altering stream communities. Understanding the role of large consumers such as fish in regulating periphyton structure and nutritional content is necessary to predict how changing diversity will interact with nutrient enrichment to regulate stream nutrient processing and retention. 2. We characterised the importan...

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