Ocean water source o Earth s interior o Extraterrestrial comet ice Ocean salinity o Evaporation increases salinity o 35 g L o N 60 ocean 40 land o S 80 ocean 20 land Life on Earth Land surface area in N hemisphere is twice that in S hemisphere o Early atmosphere no O N CO2 H2O with traces of methane and ammonia o O entered about 2 5 billion years ago Geological evidence of O formation life 2 7 billion years ago o Banded Iron Formation in Australia Formed because of oxidation iron rust Likely formed in shallow seas on continental shelves because too old to survive subduction Sedimentary formation Evidence of early life o Fossils of bacteria like organisms o Discovery of molecular fossils of cyanobacteria blue green algae in 2 1 billion year old rock Stromatolites modern ancient Shark Bay Australia South Africa o Layered microbial mat communities that grow in shallow seas and accrete sediments o Filamentous cyanobacteria are important to the component of the mat o Ancient Fine layers depict the layers of the microbial may and sediment that accumulate as it grows towards the surface Filamentous cyanobacteria produce molecular oxygen through the process of oxygenic photosynthesis Did life begin at hydrothermal vents o Protection from UV radiation o Liquid water o Source of reduced chemicals for energy o Mineral surfaces suitable for assembly of the biochemicals of life Scientific Method theory law o Curiosity observations measurements hypothesis experiments o Hypotheses can be independently tested and theories can evolve as new information is obtained The elements of life o Four elements make most biomass major components C O H N o 9 macronutrients Na Mg P S Cl K Ca I Si o Micronutrients Fe Cu Zn Mn Photosynthesis Fe is a limiting nutrient in the ocean o Organisms are the base of most food webs o All organisms need a source of energy and carbon for growth o Photoautotrophs use light energy and inorganic carbon CO2 for growth growth o Chemoheterotrophs use chemical energy and organic carbon for Sun producers phytoplankton consumers zooplankton o Primary production production of organic compounds from CO2 through the process of photosynthesis and chemosynthesis Often normalized to the surface area of the ocean Does primary production vary with depth Why Yes light doesn t always penetrate deep enough and nutrients may not be available everywhere such as the surface waters Annual primary production in ocean is about 50 55 Pg C On land it s 55 60 Pg C About 18 occurs in coastal margins and about 77 in open Why are the rates of primary production low in some regions ocean of the open ocean Less nutrients no constant supply of fresh nutrients stratification Diatom Coscinodiscus Light o Phytoplankton have a hard structure frustule made of silica o Quality and quantity are critical factors affecting biodiversity and the distribution and activity of marine organisms o Penetration of wavelengths varies with depth o Which wavelengths of light have the most energy Shorter wavelengths towards the violet end o Why is the open ocean blue Blue light penetrates the deepest and it s the last to be o Coastal ocean has more particles to absorb light Appears green because it is the last color being attenuated attenuated instead of blue Photosynthesis exceeds respiration in the euphotic zone 100 125m accounts for only 1 2 ocean volume o Diphotic zone twilight zone to about 600m o Aphotic zone below 600m Temperature o Regulates rates of biological physical and chemical processes o Thermophiles high temperatures o Mesophiles warm temperate o Psychrophiles cold temperatures o Effects on growth rates of microorganisms Each class has own temperature optimum Q10 rate of reactionat 10 rate of reaction at 2 3 is common for biological processes minimum membrane gelling transport processes so slow that growth can t occur optimum reactions occur at maximum rates maximum protein denaturation collapse of cytoplasmic membrane thermal lysis Biochemicals o Carbohydrates C H O o Lipids C H O P o Proteins C H O N o Nucleic acids C H O N P Saturated all single bonds C filled with as many H as possible Unsaturated double bonding C not full with H What limits primary production in high latitude surface waters o Sunlight nutrients N Fe and Si are limiting How do cells move substrates across the cell membrane o Selectively permeable lipid bilayer o O CO2 some H2O and other small nonpolar molecules can go through o Glucose and other large polar water soluble molecules ions and H2O molecules are too large and must be transported 3 transport types diffusion high low concentrations transport proteins o active through ATPase pump against concentration gradient requires ATP o passive water soluble substances high low acts as a channel Which wavelengths and colors of visible light penetrate the deepest in coastal and open ocean waters o Open blue about 450 nm o Coastal green about 500 nm Advantages of small size o Greater surface to volume ratio advantage for transporting substances to meet metabolic demands Sphere 4 SA 3 V 4 3 r 2 r3 o The bigger the volume the greater the need for nutrients Photoautotrophs o Capture sunlight and use it for photosynthesis Plants some bacteria protistans single celled organisms photosynthesis1 H2O split with light energy O released2 ATP energy drives biosynthesis of glucose from CO2O CO2 H2O O requir edaerobic respiration1 glucose degraded to CO2 and H2O2 ETC release energy to drive ATP formationCO2 H2O releas ed requir ed releas ed Figure O releasedO requiredaerobic respirationCO HO releasedCO HO required Photosynthesis o 12 H 2O 6C O2 6 O2 C 6 H 12O6 6 H 2 O o Occurs in chloroplasts 2 outer membranes stroma fluid interior thylakoids inner membrane system o 2 stages capture ad convert sunlight energy to chemical energy reassemble photosynthetic bacteria and could have evolved from bacterial endosymbionts light dependent water light uptake O release in thylakoid sends electrons to ETC to make ATP pigments absorb light energy and give up e enter ETC light independent reactions stroma CO2 uptake glucose release new H2O Calvin Benson Cycle o harvesting light requires pigments synthesis part of photosynthesis chlorophylls main pigments of most photoautotrophs PAR photosynthetically active radiation 400 700 nm Why is chlorophyll green It reflects green light and absorbs all others Accessory pigments carotenoids phycobilins anthocyanins beta carotene o Arrangement of photosystems within the thylakoid