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Study Guide: Exam 4
Primary Productivity |
The rate at which energy (carbon) is stored in organic matter |
Photosynthesis
|
Solar radiation
production of carbs from CO2 & water in the presence of chlorophyll
using light energy and releasing oxygen (chemical energy) |
Chemosynthesis
|
Chemical reactions
bacteria-like organisms trap chemical energy by oxidation |
Factors That Affect Productivity
|
Nutrient availability (river runoff & upwelling)
solar radiation:
compensation depth (net photosynthesis becomes zero)
euphotic zone (surface to ~ 100 m) |
Variability of Primary Productivity
|
Polar Regions: productivity peaks during the summer & is limited by sunlight
Tropical Regions: productivity is low year-round and is limited by nutrients
Temperate Regions: productivity peaks in spring/fall, limited by lack of solar radiation in winter/lack of nutrients in summer |
Producers
|
Autotrophic
can nourish themselves through photosynthesis or chemosynthesis
examples: algae, plants, archaea, photosynthetic bacteria |
Consumers
|
Heterotrophic
eat other organisms
can be herbivores, carnivores, omnivores, bacteriovores |
Decomposers |
Break down dead organisms or waste |
Iron Hypothesis
|
To increase productivity they could add iron, the only nutrient the ocean lacks
adding iron increases the amount of CO2 removed from the atmosphere |
Upwelling
|
Greatly enhances conditions for life by lifting cold, nutrient-rich water to the sunlit surface
areas of coastal upwelling are sites of high productivity |
Harmful Algal Bloom (HAB)
|
Occur when there's a high concentration of dinoflagellates that produces anoverabundance of algae that's detrimental to marine animals, humans, environment
results from increased availability of nutrients
don't color the water red like, red tides |
Biogeochemical Cycle
|
Chemical components of organic matter enter through photosynthesis/chemosynthesis
passed on to consumers through feeding
detritus sinks & feeds organisms living below the surface
or undergoes decomposition which returns nutrients through upwelling |
Gross Ecological Efficiency
|
Ratio of energy passed on to the next higher trophic level
the energy received from the trophic level below |
Food Chain
|
Sequence of organisms through which energy is transferred
primary producer > herbivore > carnivores > "top carnivore" |
Food Web
|
A group of interrelated food webs
a branching network of many consumers
consumers more likely to survive with alternative food sources |
Biomass Pyramid
|
Shows energy transfer b/t trophic levels
the number of individuals & total biomass decreases at successive trophic levels
organisms increase in size |
Maximum Sustainable Yield (MSY) |
maximum fishery biomass that can be removed yearly and still be sustained by the fishery ecosystem |
Overfishing |
When harvesting of stocks takes place so rapidly that the majority of the population is sexually immature and therefore can't reproduce |
Bycatch
|
Non-commercial fish caught unintentionally by fisheries intending to catch commercial fish
can be up to 8x more than intended catch
birds, turtles, dolphins, sharks |
Marine Mammals Protection Act
|
In 1992 a special addendum was added to protect dolphins
purse seine nets modified so that dolphins could be released alive
driftnets/gill nets banned in 1989
reduced dolphin mortality as bycatch but dolphin populations haven't rebounded accordingly
reduction of dolphin survival & birth rates |
Purse Seine Net
|
Large fishing net that resembles purse
set around a group of organisms and the bottom is drawn tight to capture them |
Driftnet |
Made of monofilament fishing line that catches organisms by entanglement |
Equatorial Upwelling
|
Result of trade winds driving western equatorial currents on either side of equator;divergence
Ekman transport causes surface water to diverge towards higher latitudes
movement of deeper nutrient-rich water into the surface
eastern Pacific Ocean |
Coastal Upwelling
|
Result of windblown surface water moving offshore
prevailing winds blow towards the equator & along western continental margins; surface waters driven away from coast
movement of deeper nutrient-rich water into the surface
along west coasts of continents |