Mesopelagic & Bathypelagic Zone
Deep Sea Benthos
Hydrothermal Vents
Oligotrophic Systems & Coral Reefs
Polar Regions
100
Define the mesopelagic zone (with depth range) and describe three physical characteristics of it
Mesopelagic zone (200-1000m) - base of euphotic zone to 1000m
Physical characteristics: Dark, Cold (~3.5C), Constant salinity, Oxygen present (except for OMZs), high nutrients, increasing pressure, damped seasonality
100
How does biomass vary latitudinally in the benthos?
Higher latitudes have higher biomass (because of high particle fluxes)
100
Where can hydrothermal vents be found?
Along spreading centers - like the Galapagos Rift
100
Define oligotrophic, describe the two types of oligotrophic systems, and give an example of an oligotrophic system
Oligotrophic- Waters with low biomass (chlorophyll)
Low biomass/low nutrients: Sargasso Sea, N.Pacific subtropical gyre
Low biomass/high nutrients: Equatorial Pacific (HNLC)
100
Describe two differences between the Arctic and the Antarctic
Arctic is an oceanic basin and Antarctica is a continent
Arctic has high terrestrial influence and Antarctica does not
Differences in ice structures
Arctic polar bears and Antarctic penguins
200
Give two biological reasons for luminescence
Light is a lure to attract other kinds of organisms
Light for vision (to avoid predators/find prey)
Light for species recognition (sexual reproduction or for schooling)
Startling/confusing a predator
Burgler Alarm (expose your predator to its predator)
Aposomatic (warning colors)
Camouflage
200
Describe two different substrate types in the deep sea benthos
Hard rock: Spreading centers, active faults, seamounts, offshore banks, other organisms, Manganese nodules, submarine canyon walls
Sandy bottoms
Sediment (terrigenous, biogenic, aeolian, and cosmic)
200
What is chemosynthesis? Describe a compound used in chemosynthesis and a product from that reaction.
H2S---S
S---SO4
Fe2+---Fe3+
CH4---CO2
200
What is a coral? What role does it play in its environment?
A coral is a soft bodied invertebrate that is a cnidaria/anthozoa. Some coral also have bacterial symbionts. Corals are ecosystem engineers that create and modify their habitats and help shape physical environmental parameters.
200
Describe trends in macronutrients and micronutrients in the polar regions
High macronutrient supply (light limited system)
Low micronutrient supply (far away from sources)
300
Describe two ways deep sea organisms get food
Detritus: Marine snow & other flux from upper water column (also large food falls)
Vertical migration to euphotic zone
Prey on each other
Vertical migration ladder
Chemosynthesis
300
What is the difference between epifauna and infauna? Give an example of each.
Epifauna: Live on/above the surface ex) polychaetes, fish, crabs, Sea cucumbers, echinoderms-brittle stars, sea stars, barnacles, worms, sponges
Infauna: Live in the sediment ex) snails, ciliates, small worms, bacteria, protozoans.
300
Name a hydrothermal vent organism and one adaptation it has for its environment
Vestimentiferan tube worms (Riftia pachyptila): sulfate oxidizing, carbon fixing bacteria for nutrition
Giant clams- Calyptogena,magnifica- Sulfide-reducing bacterial symbionts live in their gills and make up to 75% of the gill tissue
Mussel- Bathymodiolus thermophilis- have bacterial symbionts in gills. Still have a functional mouth and gut , so some nutrition from sinking particles.
Scavenging brachyuran crabs- Bythograea, Cyanograea nestle within vestmentiferan and mussel clumps
Rimicaris- caridean shrimp- appendages covered with filamentous, sulfide oxidizing bacteria. Hold appendages in vent flow, to nourish this ‘on-board’ bacterial farm. Then scrape bacteria off with other feeding appendages and eat them. Also ingest sulphide particles from associated free-living microorganisms. Lack ‘normal’ eyes., but have dorsal organs containing visual pigment that are thought to detect hot water plumes
Other organisms: pogonophoran worms/ Polychaete worm, White galatheid crab, Caridean shrimp,
300
Describe a characteristic of an oligotrophic system and how an organism either adapts to the characteristic or causes the characteristic
Extremely low nitrate concentrations (also silicate/phosphate/ammonium) - N-fixers like Trichodesmium
Low phytoplankton biomass - top layer nutrient limited / lower layer light limited - Prochlorococcus- can capture light at depth
High short term growth rates but high grazing prevent build up - seasonal growth/ blooms of phytoplankton
High surface temperatures- well stratified
Microbial food web important (recycling) - bacteria
300
Describe krill's role in the Southern Ocean's food web
Krill central in food web, with the major predators being crabeater seals, whales, fish, birds and penguins; most other organisms are dependent on those that feed on krill; since krill are not evenly distributed, neither are the predators;
Reaches extremely high biomass, forms superswarms, extremely dense accumulations of krill.
Major grazer in the Antarctic (euphausiid), mostly herbivore, but eat copepods and microzooplankton too.
400
Give three characteristics of an ideal mesopelagic/bathypelagic species
Density: Increase water content of body, don't oscify skeleton, gas filled chambers (swim bladders)
Colors: Countershading (dark on back, light on belly), black or red (black absorbs light/ red looks blue/hard to see)
Metabolic Adaptations: Efficient energy utilization, live long and grow slow
Bioluminescence
Visual Enhancements: Large eyes, long and closely packed rods, tapetum (reflects light), additional pigments, placement (upward looking)
400
Describe a feeding mode of deep sea benthos organisms and give an example of an organism that uses this feeding mode
Deposit Feeding; (subsurface and surface); feed on detrital material and smaller organisms (microbes-bacteria & protozoans, nematodes too) in sediments; example polychaetes, holothurians
Active Suspension Feeding; occurs above sediments; feed on particles in water (often resuspended); actively pump water for feeding; examples: tunicates and sponges
Passive Suspension Feeding; occurs above sediments; feed on particles in water (often resuspended); filter water moved past organism; example crinoids
Mobile carnivores/scavengers; move large distances for food; feed on surface; examples fishes and amphipods.
400
How do organisms get from one vent site to another?
Deep current transport planktonic larvae (e.g., Riftia)
Some larvae may be able to delay settlement for months at a time.
Dead whale/wood falls can be used as stepping stones
400
Describe one anthropogenic influence and how it effects coral
Rising water temperature- coral have narrow ranges of temperatures & high temperatures can cause bleaching (loss of symbiotic algae)
Ocean acidification - impacts the calcium carbonate precipitation and formation of the coral structure
Sedimentation- light limitation and hurts structure
400
What is polar amplification? Is it a positive or negative feedback loop?
Warming atmosphere leads to sea ice retreat leads to reduced surface albedo which leads to increased absorption of solar radiation which contributes to additional atmospheric warming
Positive feedback loop
500
Describe one mechanism of how bioluminescence works
Luciferin-luciferase reactions in photocytes/ photophores
Photoproteins (protein itself emits light) - triggered by reactions with other molecules
Symbiotic photobacteria
500
Describe one way global warming may impact deep sea benthos
Tropical/mid-latitudes: Increase ocean stratification leading to a decline in upwelling and primary production
May reduce net primary production over much of the ocean (15-20% decline in NPP may lead to a 50% decline in abyssal POC flux)
Shift pelagic ecosystems from (a) diatom- and large zooplankton-dominated assemblages with higher export efficiencies to (b) picoplankton- and microzooplankton-dominated assemblages with lower export efficiencies
500
Compare hydrothermal vents and the rest of the deep sea in the following categories:
Growth rate
Species Diversity
Biomass
Metabolic Rate
Hydrothermal vents have:
higher growth rate
lower species diversity
higher biomass
high metabolic rate
500
What is a reef? Where might you find a coral reef? Name two other organisms that live on coral reefs
A reef is a ridge of rock and sand just below the surface of the ocean where coral create a biological 3D structure
Reef forming coral are typically warm water species and are usually found in shallow tropical waters like the Caribbean or in Polynesia
Algae, herbivorous fish (scraper/grazer/farmer/ excavator), carnivorous fish, sharks, moray eels, bivalves, worms, larvae, sponges, microbes
500
Choose one species in either the Arctic and Antarctic and describe how it will be impacted by climate change.
Decline in Adelie penguins due to ice coverage reduction and shrinking range (and subpolar species invasion)
Literally unlimited other answers to this