Study Guide: Exam 4
24 Cards in this Set
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Primary Productivity
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The rate at which energy (carbon) is stored in organic matter
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Photosynthesis
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Solar radiation
production of carbs from CO2 & water in the presence of chlorophyll
using light energy and releasing oxygen (chemical energy)
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Chemosynthesis
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Chemical reactions
bacteria-like organisms trap chemical energy by oxidation
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Factors That Affect Productivity
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Nutrient availability (river runoff & upwelling)
solar radiation:
compensation depth (net photosynthesis becomes zero)
euphotic zone (surface to ~ 100 m)
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Variability of Primary Productivity
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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
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Producers
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Autotrophic
can nourish themselves through photosynthesis or chemosynthesis
examples: algae, plants, archaea, photosynthetic bacteria
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Consumers
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Heterotrophic
eat other organisms
can be herbivores, carnivores, omnivores, bacteriovores
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Decomposers
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Break down dead organisms or waste
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Iron Hypothesis
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To increase productivity they could add iron, the only nutrient the ocean lacks
adding iron increases the amount of CO2 removed from the atmosphere
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Upwelling
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Greatly enhances conditions for life by lifting cold, nutrient-rich water to the sunlit surface
areas of coastal upwelling are sites of high productivity
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Harmful Algal Bloom (HAB)
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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
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Biogeochemical Cycle
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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
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Gross Ecological Efficiency
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Ratio of energy passed on to the next higher trophic level
the energy received from the trophic level below
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Food Chain
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Sequence of organisms through which energy is transferred
primary producer > herbivore > carnivores > "top carnivore"
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Food Web
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A group of interrelated food webs
a branching network of many consumers
consumers more likely to survive with alternative food sources
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Biomass Pyramid
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Shows energy transfer b/t trophic levels
the number of individuals & total biomass decreases at successive trophic levels
organisms increase in size
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Maximum Sustainable Yield (MSY)
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maximum fishery biomass that can be removed yearly and still be sustained by the fishery ecosystem
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Overfishing
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When harvesting of stocks takes place so rapidly that the majority of the population is sexually immature and therefore can't reproduce
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Bycatch
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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
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Marine Mammals Protection Act
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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 & bir…
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Purse Seine Net
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Large fishing net that resembles purse
set around a group of organisms and the bottom is drawn tight to capture them
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Driftnet
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Made of monofilament fishing line that catches organisms by entanglement
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Equatorial Upwelling
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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
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Coastal Upwelling
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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
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Study Guide: Exam 4