Lecture 14 Flashcards
Coastal subtidal habitats are dominated by what species?
Foundation species
-seagrass
-algae
-epibenthic invertebrates
-corals
How do seagrasses reproduce?
Sexually (pollen transported in water) and asexually
Where do seagrasses occur?
in soft sediments
What are seagrasses limiting factors?
-light (high)
-flow (intermediate)
-turbidity
Where is seagrass more likely to survive?
in more diverse plots
The more diverse plots contain which species?
Halodule, a species that performs better
What do seaweeds do?
-stabilize sediments
-trap and supply nutrients
-enhance organic matter
What is the role of seagrass as a foundation species?
-provide structure on a flat enviroment
-settlement substrate
-shelter
-nursery habitat
What does seagrass do to mitigate disease risk?
Seagrass helps reduce the amount of bacteria where it is present.
Where do rocky reefs and kelp forests thrive?
on hard bottoms and in cold water
What do dominant species in the rocky reef depend on?
Depth; produces live in shallower areas
Aspect: producers on horizontal
What happens when light availability decreases?
There is a shift from producer dominant system to an invertebrate dominated system because they don’t need light
What are the requirements of an alternate stable state?
-same location
-same environmental conditions
-stable
-stable over one complete population turnover
What are Kelp?
large brown algae
What are canopy kelps?
-grow from bottom to surface
-provide structure in the water column
- have Pneumatocysts (air bladders that float)
What are the pneumatocysts filled with?
Carbon monoxide
What species are present in kelp forest zonation?
-canopy kelps
-understory kelps
-benthic invertebrates
What are the grazers present in kelp forests?
urchins and abalone
Kelp detritus is an important food source for which group ?
Benthic suspension feeders and detritivores
What is the effect of bottom-up in kelp forests?
-storms (El NIno) cause disturbance
-Nutrients drive productivity
-upwelling is directly related to kelp growth
What is the effect of top-down impacts of kelp forests?
-storms (El NIno) cause disturbance
-Nutrients drive productivity
-trophic cascade (kelp,urchin, sea otter, Orca)
Where do coral reefs occur?
-tropics and subtropics
-open ocean conditions
Name some taxa present in the coral reef?
-coralline algae
-sponges
-worms
-corals
Zooxanthellae provide coral with what?
Carbohydrates and increased calcification
What stresses zooxanthellae ?
-disease
-salinity
-temperature
What are coral reefs top-down and bottom-up impacts?
-storms
-zooxanthellae production is largely light-dependent
-consumed by predatory fish and seastars
-mortality from disease
What threatens seagrass?
coastal development, growing human populations, climate change, tourism
What threatens kelp?
commercial kelp harvesting, pollution, climate change, invasive species and diseases
What threatens corals?
diseases, predators, storms, earthquakes, hurricanes, overfishing, pollution, tourism, climate change, coastal development
What happens is seagrass decline?
decrease in primary production, carbon sequestration, and nutrient cycling in the coastal zone
What happens to kelp if they decline?
abalone and fish vanished, sea urchins declined, primary production, biodiversity
What happens if coral decline?
biodiversity, extinction of some fish, no shelter or spawning ground for fish
