Understanding the Environmental Context of Algal Priming of Coarse Particulate Organic Matter
 Decomposition in Streams

Start Date

26-10-2018 8:00 PM

End Date

26-10-2018 10:00 PM

Description

Streams can obtain energy from two main sources: autochthonous organic matter or allochthonous inputs of organic matter. Interactions between organisms involved in these two types of energy acquisition can exist within biofilms. Biofilms are microcommunities of algae, fungi, bacteria, and protozoa that form on inert and organic substrata. Previous experiments have observed interactions between photosynthetic and heterotrophic organisms within biofilms in a process called algal priming. The release of a labile carbon source by algae may stimulate the decomposition of coarse particulate organic matter by heterotrophic organisms. To better understand algal priming, we evaluated the environmental factors that may influence the process within biofilms. Presence of light, nutrients, and a labile carbon source were manipulated using shading and chemical diffusing substrata. Unbleached cotton strips were attached to clay saucers containing the chemical diffusing substrata that was manipulated into four treatments: a control, the addition of nutrients, the addition of a labile carbon source, and the addition of both nutrients and a labile carbon source. The clay saucers were attached to a tile and placed in a stream under a transparent or darkened shade. After one week, cotton strips were collected and tested for respiration and tensile strength which is a measure of decomposition. Flooding prevented further sample collection beyond one week. A future study will involve placing cotton strips within transparent or darkened tubes into 25 streams of varying stream order and nutrient content. After one month, the cotton strips will be collected and evaluated for decomposition, algal biomass, bacterial biomass, fungal biomass, extracellular enzyme activity, and respiration. In examining environmental context, we aim to provide information to better understand the role priming may play in the cycling of carbon within streams.

Keywords

stream ecology, algal priming

Type

Poster

Session

Poster session

Language

eng

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Oct 26th, 8:00 PM Oct 26th, 10:00 PM

Understanding the Environmental Context of Algal Priming of Coarse Particulate Organic Matter
 Decomposition in Streams

Elaine Langone Center, Terrace Room

Streams can obtain energy from two main sources: autochthonous organic matter or allochthonous inputs of organic matter. Interactions between organisms involved in these two types of energy acquisition can exist within biofilms. Biofilms are microcommunities of algae, fungi, bacteria, and protozoa that form on inert and organic substrata. Previous experiments have observed interactions between photosynthetic and heterotrophic organisms within biofilms in a process called algal priming. The release of a labile carbon source by algae may stimulate the decomposition of coarse particulate organic matter by heterotrophic organisms. To better understand algal priming, we evaluated the environmental factors that may influence the process within biofilms. Presence of light, nutrients, and a labile carbon source were manipulated using shading and chemical diffusing substrata. Unbleached cotton strips were attached to clay saucers containing the chemical diffusing substrata that was manipulated into four treatments: a control, the addition of nutrients, the addition of a labile carbon source, and the addition of both nutrients and a labile carbon source. The clay saucers were attached to a tile and placed in a stream under a transparent or darkened shade. After one week, cotton strips were collected and tested for respiration and tensile strength which is a measure of decomposition. Flooding prevented further sample collection beyond one week. A future study will involve placing cotton strips within transparent or darkened tubes into 25 streams of varying stream order and nutrient content. After one month, the cotton strips will be collected and evaluated for decomposition, algal biomass, bacterial biomass, fungal biomass, extracellular enzyme activity, and respiration. In examining environmental context, we aim to provide information to better understand the role priming may play in the cycling of carbon within streams.