BIOL 4262 Exam 3 Marine and Coastal Ecosystem Dynamics:
Integrative Analysis of Phytoplankton, Chlorophyta, Rhodophyta,
Phaeophyta, Seagrass Beds, Kelp Forests, Algal Mats, Primary
Productivity, Trophic Cascades, TMII, DMII, Herbivory, Grazers,
Predation, Keystone Species, Foundation Species, Biodiversity,
Ecophysiology, Nitrogen Fixation, Heterocysts, Epiphytes,
Mesograzers, Carbon Sequestration, Sediment Stabilization, Intertidal
Zonation, Rocky Shore Paradigm, Competition, Disturbance, Tolerance,
Larval Settlement, Oceanographic Forcing, Nutrient Dynamics,
Eutrophication, Climate Change Impacts, Coastal Resilience, Ecosystem
Services, and Anthropogenic Stressors Exam Questions Verified and
Provided with Complete A+ Graded Rationales Latest Updated 2026
Identify and describe different kinds of marine photosynthesizers (know the phyla). Differentiate
among the different kinds.
Green seaweed (chlorophyta)
-found in temperate and tropical waters
,Red seaweed (rhodophyta)
-have a feather-like quality; small in size
-found in intertidal marine, rarely in freshwater
Brown seaweed (phaeophyta)
-found in cold waters in temperate and polar regions
Identify the three major parts of brown algae. Differentiate among seagrass beds, algal mats,
kelp forests.
1. Holdfast
2. Stipe
3. Frond
seagrass bed: underwater ecosystem (dense meadow) formed by seagrasses
algal mat: microbial mat that forms on the surface of water or rocks
kelp forest: underwater areas with a high density of kelp
What are seagrasses? Where are seagrasses found and why are they found there?
Seagrasses are flowering, submerged plants that are typically found in shallow waters (depth
from 1 to 5 meters), as they require light for growth.
,They form dense beds in tropical and temperate shallow nearshore and estuarine habitats. They
compose approximately 0.1% of the sea floor.
Explain the ecological importance of seagrasses. How do sea grass beds alter the physical
environment? Biodiversity?
1. Seaweeds can serve as food for many organisms
2. Seaweeds provide structure and habitat for organisms. Kelp forests especially provide
structure and habitat in ecosystems. (increase biodiversity)
3. Intertidal seaweeds can facilitate existence of other species by reducing desiccation and
buffering temperatures. (increase biodiversity)
4. Seaweeds can also dominate substrate and outcompete other species. Competitive exclusion
is observed among seaweeds. (alter enviroment)
Explain some of the threats to seagrasses.
1.Turbidity and epiphytic algae reduce light available to seagrasses (increase of them due to run
off nutrients)
•Eutrophication may enhance phytoplankton and epiphyte growth
2.Loss of large fish might alter food webs in a trophic cascade (due to overfishing)
, Explain the relative importance of competition, predation, disturbance, and tolerance in the
structure of seagrass communities. Be able to compare to other communities.
Competition
Some species dominate when disturbance and grazing pressure are low
-seagrass can outcompete other plant species to dominate substrate
disturbance
-very important
natural (hurricanes, grazing) and human (overfishing, nutrient runoff) (see grazer and light
mediated hypothesis)
predation:
-important, grazers decline seagrasses, larger predators of grazers can help seagrasses through
trophic cascade and TMII
tolerance:
-affects where types of seagrass can live, depending on tolerance to temperature and sunlight
Integrative Analysis of Phytoplankton, Chlorophyta, Rhodophyta,
Phaeophyta, Seagrass Beds, Kelp Forests, Algal Mats, Primary
Productivity, Trophic Cascades, TMII, DMII, Herbivory, Grazers,
Predation, Keystone Species, Foundation Species, Biodiversity,
Ecophysiology, Nitrogen Fixation, Heterocysts, Epiphytes,
Mesograzers, Carbon Sequestration, Sediment Stabilization, Intertidal
Zonation, Rocky Shore Paradigm, Competition, Disturbance, Tolerance,
Larval Settlement, Oceanographic Forcing, Nutrient Dynamics,
Eutrophication, Climate Change Impacts, Coastal Resilience, Ecosystem
Services, and Anthropogenic Stressors Exam Questions Verified and
Provided with Complete A+ Graded Rationales Latest Updated 2026
Identify and describe different kinds of marine photosynthesizers (know the phyla). Differentiate
among the different kinds.
Green seaweed (chlorophyta)
-found in temperate and tropical waters
,Red seaweed (rhodophyta)
-have a feather-like quality; small in size
-found in intertidal marine, rarely in freshwater
Brown seaweed (phaeophyta)
-found in cold waters in temperate and polar regions
Identify the three major parts of brown algae. Differentiate among seagrass beds, algal mats,
kelp forests.
1. Holdfast
2. Stipe
3. Frond
seagrass bed: underwater ecosystem (dense meadow) formed by seagrasses
algal mat: microbial mat that forms on the surface of water or rocks
kelp forest: underwater areas with a high density of kelp
What are seagrasses? Where are seagrasses found and why are they found there?
Seagrasses are flowering, submerged plants that are typically found in shallow waters (depth
from 1 to 5 meters), as they require light for growth.
,They form dense beds in tropical and temperate shallow nearshore and estuarine habitats. They
compose approximately 0.1% of the sea floor.
Explain the ecological importance of seagrasses. How do sea grass beds alter the physical
environment? Biodiversity?
1. Seaweeds can serve as food for many organisms
2. Seaweeds provide structure and habitat for organisms. Kelp forests especially provide
structure and habitat in ecosystems. (increase biodiversity)
3. Intertidal seaweeds can facilitate existence of other species by reducing desiccation and
buffering temperatures. (increase biodiversity)
4. Seaweeds can also dominate substrate and outcompete other species. Competitive exclusion
is observed among seaweeds. (alter enviroment)
Explain some of the threats to seagrasses.
1.Turbidity and epiphytic algae reduce light available to seagrasses (increase of them due to run
off nutrients)
•Eutrophication may enhance phytoplankton and epiphyte growth
2.Loss of large fish might alter food webs in a trophic cascade (due to overfishing)
, Explain the relative importance of competition, predation, disturbance, and tolerance in the
structure of seagrass communities. Be able to compare to other communities.
Competition
Some species dominate when disturbance and grazing pressure are low
-seagrass can outcompete other plant species to dominate substrate
disturbance
-very important
natural (hurricanes, grazing) and human (overfishing, nutrient runoff) (see grazer and light
mediated hypothesis)
predation:
-important, grazers decline seagrasses, larger predators of grazers can help seagrasses through
trophic cascade and TMII
tolerance:
-affects where types of seagrass can live, depending on tolerance to temperature and sunlight
