Macroalgal seaweeds Flashcards
What are the three main life zones in the biosphere?
- Open sea
- Shore
- Land
What role do algae play in ecosystems compared to terrestrial plants?
Algae play a role similar to that of terrestrial plants, contributing to ecosystem productivity and supporting biodiversity
What is the importance of macroalgae (seaweeds)?
Macroalgae are vital in providing habitat, food, and shelter for various marine organisms and contribute significantly to the global carbon budget
They are also bioindicators of chemical changes, such as nutrient inputs in the environment
How do macroalgae contribute to marine ecosystems?
They bring energy (carbon) into the system, provide food for other organisms, and help stabilize areas by reducing wave action
The decay of seaweeds, especially after storms, releases organic matter that supports heterotrophic activity
What are the main factors affecting the zonation of seaweeds on rocky shores?
- Salinity
- Exposure
- Abrasion
- Wave action
What is the significance of kelp forests in marine ecosystems?
Kelp forests provide shelter and food for various marine species, including large carnivores like tuna and sea otters
How do extreme environments impact polar seaweeds?
Polar seaweeds must endure long periods of darkness under sea ice and adapt to complex biochemistries to survive
Adaptations help seaweeds survive predation and microbial pathogens in these harsh environments
What distinguishes brown algae from other macroalgae?
Brown algae belong to the phylum Phaeophyta and are characterized by their large size, the presence of fucoxanthin, and the ability to store laminarin as a carbohydrate
They are primarily marine and can be found in temperate, boreal, and polar waters
What are the unique features of red algae (Rhodophyta)?
Red algae contain phycobilisomes with phycoerythrin, which gives them their red color, and they have a unique form of carbohydrate metabolism
They are particularly abundant in tropical and warm waters but are also found in cooler regions
How do green algae (Chlorophyta) differ from brown and red algae?
reen algae are highly diverse and include both microalgae and multicellular forms. They are the ancestors of land plants
Crucial for understanding the evolution of multicellularity and the transition to land
What are the uses of macroalgae in human industries?
Macroalgae are used to produce alginates, agar, carrageenan, and laminarin, which are used in food, medical applications, and even tissue engineering
Valuable as thickeners, emulsifiers, and preservatives
What is the primary storage carbohydrate in brown algae?
Brown algae store laminarin, a carbohydrate, in vacuoles
Can make up 34% algae’s body weight
How do seaweeds help protect delicate species in their habitat?
Seaweeds reduce physical energy from waves, allowing more delicate species to thrive beneath their canopy
Vital for biodiversity of marine ecosystems
How do brown algae adapt to the challenges of wave action and desiccation?
Brown algae have tough, flexible cell walls made of algin and cellulose, which help them withstand mechanical stresses and prevent desiccation
Algin helps them stay buoyant in water, and cellulose adds rigidity
What are the main ecological functions of green seaweed in intertidal zones?
Green seaweed typically occupies the upper shore where they can tolerate desiccation and strong light
They are adapted to survive harsher abiotic conditions like extreme exposure to air and sunlight
What is the role of coralline red algae in coral reefs?
Coralline red algae play a critical role in stabilizing coral reef structures by growing on the reef surfaces, preventing erosion
Why do red algae have a wider range of pigments than other algae?
Red algae have pigments like phycocyanin and phycoerythrin that allow them to absorb green and blue-green light at greater depths
Pigments help red algae photosynthesize in deeper, less-lit waters
What are the reproductive characteristics of brown algae?
Brown algae have a flagellated reproductive stage and reproduce through both sexual and asexual methods
Specialized reproductive structures called receptacles
How do green algae contribute to our understanding of plant evolution?
Green algae are considered the closest relatives to land plants and share many structural, biochemical, and genetic similarities.
What is the function of the holdfast in macroalgae?
Used by macroalgae to anchor themselves to rocky substrates
Helps secure seaweed in place against strong wave action
How do macroalgae photosynthesize at different ocean depths?
Macroalgae adapt to different depths by adjusting their pigments to absorb the available light spectrum
How does the body form of brown algae differ from that of other algae?
Brown algae often have a highly differentiated body, including a holdfast, stipe (stem), and blade (fronds) for photosynthesis
What adaptations do red algae have for surviving at greater depths?
Red algae contain pigments like phycoerythrin and phycocyanin that allow them to absorb light in the green and blue spectrum, which penetrates deeper into the water
How do macroalgae contribute to nutrient cycling in marine ecosystems?
When macroalgae decay, especially after storms, they release organic materials that support microbial activity and nutrient cycling
