WK - Ecological Principles II Flashcards
What are the types of diversity in microbial ecology? (3)
- Alpha diversity: Species richness within a single sample.
- Beta diversity: Differences in species composition between samples.
- Gamma diversity: Total species richness across multiple samples within a landscape.
What is the Latitudinal Diversity Gradient? (2)
- Microbial diversity increases from the poles towards the equator.
- This trend is similar to patterns seen in macroorganisms.
What is Biogeography?
The study of the distribution of species in space and time
What factors influence the distribution of dust-associated bacteria and fungi? (2)
- Bacterial distribution (NMDS) is negatively correlated with soil pH.
- Fungal distribution (NMDS) is positively correlated with mean annual precipitation.
What characterises Primary Succession? (5)
- Starts with a barren landscape, such as bare rock or sand.
- Pioneer species such as lichens and mosses colonize the area.
- These species help create soil and conditions for other species to establish.
- Over time, the community becomes more complex, with intermediate species like grasses and shrubs.
- Eventually, a climax community develops, which is a stable community that is resistant to further change.
What is Secondary Succession? (3)
- Occurs after a disturbance where soil remains intact.
- Starts with intermediate species, not pioneers.
- Climax community may differ from the original due to the disturbance.
What happens during Glacial Retreat and Primary Succession? (4)
- Retreating glaciers leave bare rock.
- Nitrogen-fixing pioneer species (e.g., cyanobacteria, lichens) colonize first.
- Soil formation allows intermediate species to establish.
- A climax community develops over time.
What are examples of Pioneer Species and Consortia? (5)
- Cyanobacteria: These photosynthetic bacteria are often the first organisms to colonize bare rock. They can fix nitrogen, which is essential for plant growth.
- Algae: Algae, such as green algae and diatoms, can also colonize bare rock. They contribute to the formation of organic matter and provide food for other organisms.
- Fungi: Fungi form symbiotic relationships with algae, forming lichens. Lichens can break down rock and create soil.
- Lichens: Lichens are composite organisms consisting of a fungus and an alga. They are very resistant to harsh conditions and can colonize bare rock.
- Mosses and liverworts: These non-vascular plants can colonize moist areas and help stabilize soil.
What are key findings in Community Development during succession? (3)
- Richness: Increases in functional gene diversity (eggNOG, CAZy, NCyc) with soil age.
- Relative Abundance: Changes over time, e.g., increase in Alphaproteobacteria.
- Functional Potential: Expands as the community diversifies and adapts.
What are the stages of microbial succession in secondary succession? (3)
- Early Stage: Dominated by low diversity with Bifidobacterium and Enterobacteriaceae.
- Intermediate Stage: Increase in genera like Clostridium XVIII and Escherichia. Decrease in Bfidobacterium.
- Late Stage: Higher diversity with abundant Bacteroides, Faecalibacterium, and Ruminococcus.
What are Emergent Properties in microbial communities? (2)
- Functions arising from interactions of individuals.
- Can exceed the sum of individual capabilities (e.g., synergistic pesticide degradation).
Show synergetic properties: E.g. one microbe might produce an enzyme that breaks down a pesticide, while another microbe might provide the necessary nutrients for the first microbe to grow and function.
What is Facilitation and Degradation efficiency?
- Facilitation: Growth of one bacterial species can be enhanced by another (e.g., At’s growth is supported by the presence of Ct), suggesting cooperative interactions.
- Degradation Efficiency: Certain combinations of bacterial species show higher efficiency in degrading toxic metals, indicating synergistic effects.
What are the impacts of Biological Invasions on microbial communities? (2)
- Introduction to new environments can lead to proliferation and persistence.
- Amplified by climate change and globalization.
What is an example of a Multispecies Invasion?
Batrachochytrium dendrobatidis (Bd):
- A fungal pathogen causing global amphibian declines, particularly outside its endemic range in Asia.
What are the 4 main types of disturbances?
Disturbances: physical
- Alters the physical soil structure
- Changes water and oxygen gradients
- Rips apart mycelial networks
- Succession
Disturbances: chemical
- Can impact microbial physiology and growth
- Reduces biodiversity of other organisms (emergent properties)
- May select for AbR
Disturbances: nutrient pulses
- Nutrient pulses may facilitate microbial invasion
- Alters biogeochemistry and related functions
Disturbances: monoculture
- Reduced biodiversity (organisms and chemistry)
What are the impacts of disturbances on microbial communities? (4)
- Increased Copiotrophic Microbes: Resource pulses from disturbances favor copiotrophic microbes, which thrive in nutrient-rich environments, outcompeting oligotrophic microbes.
- Altered Fungal Abundance: Disturbances can either increase or decrease fungal abundance, depending on the disturbance type and fungal taxa involved.
- Shifts in Community Composition: Changes in relative abundance of taxa alter overall community structure.
- Changes in Microbial Functions: Disturbances impact functional diversity, affecting processes like nutrient cycling, decomposition, and carbon sequestration.
What are the effects of industrial agriculture practices on soil health? (4)
- Crop Residue Removal: Reduces organic matter input and limits soil carbon sequestration.
- Monocropping: Continuous cultivation of a single crop depletes soil nutrients, lowers biodiversity, and heightens pest and disease risks.
- Heavy Tillage: Damages soil structure, decreases organic matter, and leads to increased erosion.
- Chemical Inputs: Overuse of fertilizers and pesticides harms soil microorganisms, reduces biodiversity, and contributes to water pollution.
What are common conservation agriculture practices? (4)
- Crop Rotation: Improves soil health by increasing nutrient cycling, reducing pest and disease pressure, and improving soil structure.
- Cover Cropping: Planting cover crops between main crop seasons can increase organic matter, reduce erosion, and suppress weeds.
- Reduced Tillage: Minimises soil disturbance, conserve moisture, and protect soil structure.
- Organic Amendments: Adding organic amendments, such as compost and manure, can improve soil fertility, structure, and microbial activity.
How does coprophagy influence microbial succession? (3)
- Coprophagy: The consumption of fecal matter, common in animals like rodents, rabbits, and insects.
- Microbial Transfer: Facilitates the transfer of microbes between individuals and across generations.
- Gut Microbiome Shaping: Plays a key role in establishing and maintaining the gut microbiome.
