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Other Algae

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The group Stramenopiles include some phototrophic microorganisms. Members of this group possess flagella covered in numerous short, hairlike extensions, a feature that inspired the group's name, derived from the Latin words for "straw" and "hair." Some of the main categories of Stramenopiles include diatoms, golden algae, and brown algae.Diatoms are unicellular, photosynthetic eukaryotes, with over 200 known genera. They play a key role in the planktonic communities of both marine and...
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The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers use some for metabolic processes, and some is lost as heat, decreasing the amount of energy available to the next trophic level. The remaining usable amount of energy is called the net primary productivity (NPP). In terrestrial ecosystems, NPP is driven by climate, while light penetration and nutrient availability drive NPP in aquatic ecosystems.
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Red algae, also known as rhodophytes, are primarily found in marine environments, though some species inhabit freshwater and terrestrial ecosystems. These organisms exist in both unicellular and multicellular forms, with some multicellular varieties reaching macroscopic sizes.As phototrophic organisms, red algae contain chlorophyll a; however, their chloroplasts lack chlorophyll b. Instead, they possess phycobiliproteins, which serve as major light-harvesting pigments, similar to those found in...
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Microbial Growth Measurement: Indirect Methods01:27

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Estimating microbial growth is essential for understanding population dynamics and environmental adaptations. Indirect methods provide valuable insights by measuring parameters such as turbidity, metabolic activity, and biomass, enabling efficient and reproducible assessments.During exponential growth, microbial cells scatter light proportionally to their biomass, a principle used in turbidity measurements. About one million cells per milliliter produce detectable scattering, which a...
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Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ecological community’s structure. Many factors affect community structure, including abiotic factors (e.g., sunlight and nutrients), disturbances (e.g., fire or flood), species interactions (e.g., predation or competition), and chance events (e.g., foreign species invasion). Certain species—such as keystone species—also play a...
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Green algae, also referred to as chlorophytes, are different from red algae in having the chloroplasts containing chlorophylls a and b, which give them their distinct green hue. However, they lack phycobiliproteins, preventing them from developing the red or blue-green pigmentation seen in red algae. In terms of photosynthetic pigment composition, green algae closely resemble plants and share a close evolutionary relationship with them. Taxonomically Green algae belong to Phylum Chlorophyta in...
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Related Experiment Video

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Indirect effects shape macroalgal epifaunal communities.

Aldwin Ndhlovu1,2, Justin A Lathlean1, Christopher D McQuaid1

  • 1Department of Zoology and Entomology Rhodes University Grahamstown South Africa.

Ecology and Evolution
|November 12, 2021
PubMed
Summary
This summary is machine-generated.

Grazing significantly impacts algal habitat complexity and cover, indirectly affecting epifaunal abundance. Predation had no direct effect, highlighting indirect biotic interactions in intertidal ecosystems.

Keywords:
Gelidium pristoidesecosystem engineerepifaunafractalshabitatrocky shoreupwelling

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Area of Science:

  • Marine ecology
  • Benthic ecology
  • Algal reef ecology

Background:

  • Intertidal rhodophyte *Gelidium pristoides* is a key habitat former.
  • Upwelling influences nutrient supply and habitat conditions.
  • Direct predation and indirect habitat changes affect epifauna.

Purpose of the Study:

  • To investigate the direct effects of predation and indirect effects of habitat change on algal epifauna.
  • To assess the roles of grazing and nutrient supply via upwelling.
  • To understand the influence of biotic interactions on epifaunal communities.

Main Methods:

  • Field experiment with predator and grazer exclusion treatments.
  • Monitored algal cover, epifaunal abundance, and community composition over 12 months.
  • Assessed algal architectural complexity using fractal geometry.

Main Results:

  • Grazing reduced algal architectural complexity and cover, particularly at upwelling sites.
  • Predation showed no significant direct effect on epifaunal abundance.
  • Epifaunal abundance responded to habitat changes caused by grazing, not direct predation.

Conclusions:

  • Indirect effects of grazing on habitat availability and quality significantly influence epifaunal abundance.
  • Epifaunal communities are strongly shaped by indirect consequences of biotic interactions.
  • Habitat complexity and cover are crucial for supporting epifaunal communities in intertidal zones.