Flashcards in Water Deck (150)
The biological activity of an aquatic ecosystem depends on the activity of what?
What are 4 examples of primary producers?
oxygenic photoautotrophs, phytoplankton. Algae, Cyanobacteria
What is one function of cyanobacteria?
What organisms serve as a food source for chemoheterotrophs?
bacteria, protozoa, fish, other aquatic organisms.
What factors are the activity and net number of phytoplankton dependent on?
Temperature, light received, limiting nutrient availability
What limiting nutrients are phytoplankton sensitive to?
What is the photic zone?
The depth (m) that light will penetrate to in clear water
How deep will light penetrate in clear water?
How are microorganisms able to harvest the little amount of light that reaches them?
Via accessory pigments
Halotolerant organisms can reach salt levels up to what %?
__% of the ocean is deeper than ___ m.
75%, 1000 m.
What is the deepest depth of the ocean? What is the pressure here?
11 km below the surface. 1100 atmospheres (~1 atm/ 10 m)
At what depth does the temperature of the ocean stay constant? What is the constant temp?
Below 100 m, 2-3 Celcius
Synonym for open ocean
What is very low in the Pelagic Zone? Why?
Primary productivity. Lack of inorganic nutrients (nitrogen, phosphorus, iron) that are required by phytoplankton.
The open ocean is __________.
relatively low in plant nutrients and containing abundant oxygen in the deeper parts
What is the temperature like in the open ocean compared to shore?
Cooler and more constant
How are nutrients brought up to the surface in some regions of the open ocean?
wind and ocean currents cause an upwelling of water from the ocean floor --> promotes productivity
What does the majority of primary productivity come from in the open ocean?
What are prochlorophytes?
Tiny phototrophs phylogenically related to cyanobacteria: Prochlorococcus
Two common adaptations observed in pelagic microorganisms?
-Size reduction (high surface/volume ratio)
-High affinity transport systems
3 characteristics of Trichodesmium
What are the two primary producers of coastal waters?
Why is productivity usually higher in coastal waters?
Influx of nutrients from rivers and polluted water sources
What is an example of a source of influx of nutrients in coastal waters? What nutrients does this provide?
Agricultural runoff. Nitrogen, Phosphorus
What is a eutrophic body of water?
Has high biological activity due to excessive nutrients (phosphorus + nitrogen). Becomes dominated by aquatic plants or algae.
What might happen at coastal waters (eutrophic body of water)?