Shallow seas Flashcards
What is the shallow area of the ocean called?
The continental shelf
Submerged border of the continents, extending from shore to continental slope
Why is most of the continental shelf within the eupohtic zone significant?
Because photosynthesis can occur there
Euphotic zone is upper 200m of ocean where sunlight penetrates
Why are continental shelves highly productive areas?
They have high nutrient levels, support 90% of the world’s fisheries, and are more stable than intertidal zones
Supports marine food webs and economies
What are the four main reasons continental shelves are nutrient-rich?
Photosynthesis, dissolved organic/particulate matter from land and marine organisms, nutrient upwelling, and mixing by tides/currents
Factors supply food and nutrients to many marine organisms
What is an oceanic front?
A region where two discrete water bodies meet
Fronts can create biologically rich zones due to mixing
What is the primary production source on the continental shelf?
Both benthic and pelagic sources
What is the primary production source in the open ocean?
Pelagic sources
Because benthic zones in open ocean recieve little to no light
How can benthic organisms be classified?
- Size
- Location
- Habitat type
- Feeding strategy
- Lifestyle
Helps researchers understand their roles and interactions in ecosystems
What is the difference between epifauna and infauna?
Epifauna live on the sea bed; infauna live below the surface
What is recruitment in benthic communities?
The arrival of new individuals to a population, often via planktonic larvae
Can depend on environmental cues like chemical signals
What determines the distribution of benthic organisms?
The type of seafloor substrate and specific environmental cues
What percentage of temperate and tropical continental shelves are dominated by soft-bottom sublittoral communities?
Approximately 45% of temperate shelves and 30% of tropical shelves
Give two examples of animals associated with soft-bottom sublittoral communities
Norway lobsters, which burrow, and Atlantic cod, which feed on macrofauna
Important for commercial fisheries
What challenges do hard-bottom sublittoral communities face?
- Strong currents
- Requiring adaptations in sessile benthos to reduce drag
Water flow many also influence feeding strategies
Name two types of organisms common in hard-bottom sublittoral communities
Autotrophs and passive suspension feeders
What are the advantages and limitations of SCUBA in benthic surveys?
Advantages: direct observation, long-duration studies, and experimental manipulation
Limitations: time-intensive, needs good visibility, and limited to shallow waters
Used for detailed, small scale studies
Name four tools used for surveying benthic communities besides SCUBA
- Van Veen grab
- Bottom trawl
- Dredge
- Box corer
- Underwater cameras/BRUVs
True or false: Soft-sediment shallow sea habitats are homogenous and stable
False
True or false: Laminaria kelp can have fronds up to 3 m long and produce over 5kg C/m2/year
False
Which of these following statements is not correct:
A: Lithogenic inputs to the shallow seas can increase turbidity
B: Shallow seas can be significantly different between seasons
C: Tides have little impact in shallow seas
D: Productivity in shallow seas primarily occurs in the meiobenthos
D
