Open Ocean
Are oceanic or neritic food chains longer? Which food chain is more efficient?
Oceanic food chains are longer. Therefore, neritic food chains are more efficient.
1. Biomass ________ as depth increases.
2. Benthic diversity is typically ______.
3. Benthic diversity ______ as latitude increases.
1. decreases - why? few organisms can survive in harsh conditions (low organic matter input)
2. high - the only exception is diversity decreases at VERY deep depths because of the lack of food
3. decreases
What are the 3 sections/sectors of an estuary? In which section does most salinity variation occur?
1. upper
2. middle
3. lower
Most salinity variation in the middle region! Due to mixing of freshwater (from mouth of river) and saltwater (from ocean)
List the following habitat/ecosystem types in order of most to least productive:
Pelagic and Deep Sea
Estuaries, reefs, mangroves, saltmarsh, and seagrass
Continental Shelves
Estuaries, reefs, mangroves, saltmarsh, and seagrass
Continental Shelves
Pelagic and Deep Sea
What is the primary goal of fisheries science?
To estimate the amount of fish that can be harvested while leaving enough individuals to replenish (i.e. sustain) the population
- But this goal is often modified by political, economic, and social considerations
- If regulations are too conservative, there will be lots of fisheries production (can be negative, for example, if populations that rely on fisheries for food are not allowed to fish)
- If regulations are too liberal or there is no management, there will be lots of overexploitation
What are the depth zones of the ocean in order from surface to seafloor? What characteristic defines the first 3 zones?
1. Epipelagic - photic zone (light = photosynthesis = primary productivity)
2. Mesopelagic - biologically active (where the consumers are; no photosynthesis)
3. Bathypelagic - bulk of volume in ocean (No light, very little food)
4. Abyssopelagic
Deep sea organisms have many adaptations that allow them to live in these extreme conditions.
1. Some organisms have adapted to have large eyes or bioluminescence due to the lack of ______.
2. Some organisms have adapted to have decreased metabolism or gigantism due to the decreased ______.
3. Some organisms lack a swim bladder or have a gelatinous body due to increased _______ ________.
1. light
2. temperatures
3. hydrostatic pressure
Estuaries exhibit _______ biomass and ______ productivity but ______ species diversity.
1. high
2. high
3. low
How does the ratio of benthic:pelagic production correlate to the "health" of an environment?
A higher benthic:pelgic ratio is desirable in a healthy continental shelf environment – meaning more benthic producers are preferred
Are R-strategists or K-strategists more susceptible to overfishing? Describe their reproductive strategies and how this correlates.
R strategists - Short life cycles; large number of offspring; mature early; few age classes are alive at the same time -> LESS susceptible to overfishing
K strategists - Slow growth rate; few offspring; late maturity; low or inconsistent fecundity; localized distribution = MORE susceptible to overfishing
What physical factors are phytoplankton blooms dependent on? (there are 3 major ones)
1. Mixing of ocean water
2. Increasing day length (more light for photosynthesis to occur)
3. Warming air (creates a layer of buoyant water that resists mixing with denser water underneath, creating a layer of surface water high in nutrients that can be used by phytoplankton to contribute to blooming)
Particulate organic matter is categorized into 3 main categories. What are they?
1. fecal pellets
2. Molts/sinking carcasses
3. amorphous aggregates (or "marine snow" aka phytodetritus)
What is the difference between a spring and neap tide?
Spring tides are very high because the sun, moon, and earth are aligned, amplifying the gravitational force. Neap tides are very low because the sun, moon, and earth form a right angle, causing the gravitational forces to cancel out.
What are the 4 reasons why continental shelves are so productive and diverse?
1) Lots of nutrient sources - both allochthonous and autochthonous
2) Waves and currents - create turbulent flow
3) Light and Depth - located in euphoric zone, allowing for photosynthesis
4) Substrate Characteristics - hard shelf habitats provide anchorage for sessile organisms and soft shelf habitats are dominated by mobile organisms
What are the 5 important processes in fished populations?
1) Growth - how organisms are growing, how long it takes them to grow, how big they are going to get
2) Natural mortality – predation, interspecific interactions, disease, parasites, etc.
3) Fishing mortality – killed for consumption
4) Reproduction – fecundity: the number of viable female offspring that can produce eggs and larvae
5) Recruitment – number of fish that reach a specified stage in the life cycle (age of individuals joining fishery)
What are the names of the 3 major pumps that drive the biological carbon pump?
1. Vertical migration pump
2. Physical mixing pump
3. Gravitational settling pump
How do hydrothermal vents work? (there are 3 "stages")
1. hot magma chambers heat up water
2. superheated water (NOT the magma) erupts out of the seabed
3. fume cloud forms containing minerals (like hydrogen sulfide, carbon dioxide, methane, etc.)
What are the 2 types of organisms that can survive within estuaries? 2 "groups" were provided in lecture.
1. osmoregulators
2. halophytes
Both have high tolerances for the changing salinity because they regulate internal salt levels.
What are the 5 types/examples of physiological tolerance differences that can contribute to vertical zonation in intertidal regions?
1) heat stress - think about barnacles beating their cirri to cool
2) desiccation - think about seaweeds and grasses staying in lower regions because they need water to prevent drying out
3) Low O2 - as the tide goes out, there is less oxygen available (no water = less oxygen)
4) Evaporation - evaporation leads to hypersalinity
5) Precipitation - rainfall leads to hyposalinity
Knowing the shape of the natural mortality curve of a population can provide information about the impacts of harvest on different age groups.
1) If the natural mortality is high, there will be _______ of an impact of harvesting.
2) If the natural mortality is low, there will be _______ of an impact of harvesting.
1) Less
2) More
What happens to each of the following factors as depth INCREASES?
1. Nitrogen concentration (nutrients)
2. Light
3. Chlorophyll A
4. Organic matter (particulate organic carbon)
5. Temperature
1. decrease (until you reach the DEEP sea where there is an increase in nutrient availability due to marine snow)
2. decrease (once 100 m is reached, there is no more light available)
3. peaks at pycnocline, then decreases (indication of primary productivity)
4. decreases (consumed by consumers)
5. decreases (temperature is homogenous (stable) in the top layer of the ocean)
List the stages of a whale fall in chronological order AND provide a simple explanation of what happens in each stage.
1. Mobile-scavenger stage: soft tissue (muscle and blubber) is removed from the carcass
2. Enrichment-opportunist stage: animals feed on leftover scraps of meat and blubber
3. Sulphophilic stage: chemoautotrophic bacteria produce H2S (used by other sulphophilic bacteria for energy)
4. Reef stage: structures are built on mineral remnants of the skeleton
Match each type of estuary to its appropriate picture.
*Megan will show picture
Refer to slides 11-19 from the Estuaries lecture for answers.
What are the 5 drivers of vertical zonation in intertidal regions?
1) Exposure or elevation - physiological tolerance
2) Larval and adult preference
3) Competition
4) Predation
5) Behavior
1) What is maximum sustainable yield?
2) The production of new biomass, and thus possible fishery yield, is highest at __________ population sizes? (either high, low, or intermediate)
3) The MSY is at _____ the carrying capacity (K).
1) The maximum catch of fish by weight or numbers that can be taken from a stock over an indefinite period of time without depleting the population.
2) intermediate
3) 1/2