Quiz what is the primary benefit of gills Increases SA for gas exchange Podcast quiz what is the primary effect on the oceans of CO2 intake Decreases pH Podcast Quiz what impact does ocean acidification have on oyster reproduction Reduces reproduction by slowing down growth and increasing mortality Gas Exchange in Marine Invertebrates Cellular respiration digestion and organismal respiration are related how Digestion provides energy for cellular respiration Respiration o Physiological process by which oxygen moves into internal environment and carbon dioxide moves out Respiratory system o Acts in concert with circulatory system to deliver oxygen and remove CO2 o Regulate acid base balance Oxygen in the ocean o Oxygen relatively constant in sea water Usually 4 6 ppm Lower in some enclosed water bodies o Less soluble in warm water o Oxygen min layer between 40 1000 m depth Min layer created where usage is greater than replenishment by convection common in highly productive tropical oceans leads to hypoxic anoxic zone Oxygen on surface lots of biomass photosynthesis Carbon dioxide in the ocean o Very abundant 75 of gas in sea 93 of all CO2 on planet only 04 of gas in air o Most dissolved as HCO3 buffer pH constant o More protons more acidic lower number more acidic o What happens if more CO2 is added Respiration easy O2 levels fairly constant except o Pelagic animals in oxygen min layer o Benthic animals in anaerobic conditions Caused by decomposing sludge and lack of mixing dead zones o Animals that migrate through these areas o Active swimmers fish mammals anaerobic conditions in muscles Pressure o Definition unit of force per given area o Gasses exert pressure molecules move collide into surfaces which gives pressure o Partial pressure pressure a gas would have if it alone occupied a volume o Total pressure sum of partial pressures Atmospheric pressure o Pressure exerted by weight of air on Earth s surface o At sea level 760 mm Hg o 78 atmosphere is N o Oxygen is 21 air its PP is about 160 mm Hg o 760 x 21 100 160 mm Hg o Barometer to measure pressure Partial pressure gradients o Concentration gradients for gases Differ at various places throughout the respiratory circuit o Gases diffuse down their pressure gradients o Gases enter and leave the body by diffusing down pressure gradients across respiratory membranes Fick s law of diffusion o Diffusion a membrane is Proportional to SA positive slope Proportional to difference in PP across membrane positive slope Inversely proportional to distance over which diffusion takes place negative slope o Quiz what adaptations will not cause an organism to increase respiration Increase SA of respiratory structure decrease thickness of respiratory surface max the difference in PP across the respiratory membrane or decrease the difference in PP across the respiratory surface opposite of Fick s law Boundary layer o Found next to all solid surfaces o All transport of gas must occur by diffusion across this boundary layer o Caused by fluid viscosity o No slip condition set up by boundary layer pollen on car no movement of air right on top of car pollen doesn t come off o Water is more viscous closer and closer to the object speed of water slows down o High to low concentration in high they are constantly banging into one another and pushing each other farther away which is why they naturally move to low concentration Effects of flow speed on respiration o Flow speed increases respiration rate increases because the boundary layer is decreased and then there s less diffusion to get inside the organism Large respiratory surfaces needed b c o Boundary layer o Water has relatively low oxygen content Oxygen in 1 L water oxygen in 25 ml air So aquatic organism must move 1 L of water to get 1 ml of oxygen compared to only 25 ml of air to get 1 ml of oxygen for an air breather Quiz what happens to SA to volume ratio as diameter of an object gets larger o Decreases SA to volume ratio SA to volume ratio o Animal size increases SA to volume ratio decreases o Small flattened animals can use body surface as their respiratory surface o Larger animals have special structure to increase respiratory surface such as gills or lungs Invertebrate Respiration o Moisture always required o Integumentary change flatworms o Gills internal body folds of thin walled membrane o Internal respiratory surfaces not in marine book lungs tracheal system Cnidarians occurs across body wall Portuguese man o war anemone hydroid Gills variable in structure and location Parapodia similar to gills clam worms Gas exchange o Parapodia highly vascularized o Across body wall along Parapodia Echiura organism Echinoderms o Dermal branchii papullae out pocketings that do same thing as air sacs increase SA Water Vascular system o Tube feet also used for respiration Skeleton and dermal branchii o Papullae extended for respiration drawn in for protection Respiratory Trees o Muscles generate a tidal flow of oxygenated seawater in and out o Anal breathers Benefits of out or in pocketings increases SA If you were a phylum that was adapting to enhance respiration using gills what modifications would you make to increase respiratory efficiency under the following scenarios o In the water More gills on side larger gills o After moving to land Molluscs chitons o Gills extend length of body on both sides o Water passes in from sides across gills and posteriorly o Moving from land to water o Molluscs show progression of evolutionary adaptation Molluscs abalone prosobranchs o Right and left gills o Water passes in through anterior holes across gills and out posterior holes Molluscs snail o Single gill that is folded to create greater contact between water and gill greater diffusion o Water passes over gill as it circulates through mantle cavity Molluscs bivalves o Very large paired gills o Fold back on self many times o Used in respiration and feeding o Siphons draw water in powered by cilia Molluscs cephalopods o Very large paired gills except nautilus have 4 gills o Muscle generated movement of water across gills o Gas exchange across body wall as well in webbed individuals Nudibranch Molluscs pulmonates land snails with couple primitive intertidal species o Have internal lungs rather than gills Arthropods Gas exchange o Gills attached to thoracic appendages o What is the benefit of attaching the gills to the walking legs Helps move water over the gills move movement decreases boundary layer Respiration