- Podcast question: how have fish in the ocean changed when compared to the fish that would have been found several decades ago?o Fewer, smaller fish- Podcast: Fishing down food web meanso We remove the top of the food web first, then move on down the web and remove the next level- Podcast: two main impacts of fishing on oceano Removal of fish, habitat destruction with fishing gear- Podcast: why did the cod fishery in New England collapseo We overfished itFeeding and Trophic Interactions- Feeding mechanisms: filter feeding (active vs. passive)o Passive: don’t actively move through water, water passes through them to filtero Active: moves to force water across gillso Passive: effects of flow on filter feeders Fed oysters in flow-through tanks at different flow speeds and 2 different food concentrations Quantified growth of oysters when there was more flowo Blue whale lunge feeding (rorqual whales=pleats along neck/under chin) active process facilitated by muscular contraction Allometric scaling: mechanics of lunge feeding sets the upper size limits of rorquals, larger whale (reduced size of tail-more energy to move=come up to surface for air more often, larger mouth=more energy to feed) limits max size whales can reach Quiz: What will happen to rorquals if the population of krill substantially declines?- Rorquals will not grow as large due to energetic constraints (food is less abundant, can’t make larger lunges)- Deposit feedingo Very important in soft sedimentso Up to 90% of soft-sediment organismso Detritus: dead and decaying plant materialo Where do deposit feeders get their energy? Dead matter? Microbes that decompose dead matter?  Specific energy sources may differ for each deposit feeder depending on location Lugwormso Why are they important? Play an important role in mudflat ecosystem Convert detritus food into macro-organism biomass that is available to higher trophic levels (basis of food web) Resuspend particles which increases oxygen and nutrient levels in sediments Aerate the soil through bioturbation, or their disturbance of thesediment as they burrow Stabilize the sediment by secreting mucilage, a material consisting of carbs…o Quiz: more deposit feeders at an estuary fed by a slow river or open coast sandy shore with high wave action? Estuary: smaller sand particles=larger SA, deposit feeders eat food that is mostly on the surface so you want a larger SA=more food- Herbivoryo Microherbivores (snails), macroherbivores (manatees)o Feeding structure: Aristotle’s lantern most complicated jaw structure- Predationo Oyster catchers, sharks, lionfish=invasive predator- Evertible stomacho Sea stars (stick stomach outside of mouth, use tube feet, etc)- Dinoflagellates break down fish tissue and possibly release toxin- Cannibalism: tiger sharks eating their embryonic siblings in the womb- Symbiosis: coral symbiosis with zoozanthellaeo Coral bleaching is loss of symbiont- Parasitism: Orthioine griffenis- Behavior and foraging:o Bubble net feeding: humpback whaleso Dolphins use complex behavior to forage: herd lantern fish into a tight group, dolphins encircle them facing inwards, “do the wave”, sounds and wave disorient lantern fish, 2 dolphins opposite each other come in and feed for 15 seconds, happens with every dolphins, goes throughcircle twice so each dolphin feeds 2 timeso Dolphins: strand feeding, only in SC- Conditions change: if adapted to specific conditions, how do you respond when conditions change (ex: polar bears and sea ice)- Quiz: “evolutionary trap”=when conditions change. Discuss another example of an evolutionary trap. (manatees, coral with zoozanthellae)- Case study: Florida stone crab- Food webs: location of the ecosystem-Aleutian Islands, Alaskao Sea otter population finally increased and then killer whales began eating them (both have been present for a long time, why do whales eat them now?) urchin barrenso Completely changes ecosystem- Overfishing and loss of large predators around the globe- More quiz