- Ocean water sourceo Earth’s interioro Extraterrestrial—comet ice- Ocean salinityo Evaporation increases salinityo 35 g/L- Land surface area in N hemisphere is twice that in S hemisphereo N: 60% ocean, 40% lando S: 80% ocean, 20% land- Life on Eartho Early atmosphere: no O—N, CO2, H2O with traces of methane and ammoniao O entered about 2.5 billion years ago- Geological evidence of O formation/life 2.7 billion years agoo 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 lifeo Fossils of bacteria-like organismso Discovery of molecular fossils of cyanobacteria (“blue-green algae”) in 2.1 billion year old rock- Stromatolites—modern/ancient—Shark Bay, Australia/South Africao Layered microbial mat communities that grow in shallow seas and accrete sedimentso Filamentous cyanobacteria are important to the component of the mato Ancient Fine layers depict the layers of the microbial may and sedimentthat 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 radiationo Liquid watero Source of reduced chemicals for energyo Mineral surfaces suitable for assembly of the biochemicals of life- Scientific Methodo Curiosity, observations/measurements, hypothesis, experiments, theory, lawo Hypotheses can be independently tested and theories can evolve as new information is obtained- The elements of lifeo Four elements make most biomass—major components C, O, H, No 9 macronutrients Na, Mg, P, S, Cl, K, Ca, I, Sio Micronutrients Fe, Cu, Zn, Mn- Fe is a limiting nutrient in the ocean- Photosynthesiso Organisms are the base of most food webso All organisms need a source of energy and carbon for growtho Photoautotrophs—use light energy and inorganic carbon (CO2) for growtho Chemoheterotrophs—use chemical energy and organic carbon for growth 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 ocean Why are the rates of primary production low in some regions of the open ocean?- Less nutrients, no constant supply of fresh nutrients, stratification- Diatom—Coscinodiscuso Phytoplankton, have a hard structure (frustule) made of silica- Lighto Quality and quantity are critical factors affecting biodiversity and the distribution and activity of marine organismso Penetration of wavelengths varies with deptho Which wavelengths of light have the most energy? Shorter wavelengths, towards the violet endo Why is the open ocean blue? Blue light penetrates the deepest and it’s the last to be attenuatedo Coastal ocean has more particles to absorb light Appears green because it is the last color being 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 600mo Aphotic zone—below 600m- Temperatureo Regulates rates of biological, physical, and chemical processeso Thermophiles—high temperatureso Mesophiles—warm, temperateo Psychrophiles—cold temperatureso Effects on growth rates of microorganisms Each class has own temperature optimum Q10=rate of reaction at ℃ +10rate 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- Biochemicalso Carbohydrates—C, H, Oo Lipids—C, H, O, Po Proteins—C, H, O, No 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 bilayero O, CO2, some H2O and other small, nonpolar molecules can go througho 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 proteinso active—through ATPase pump—against concentration gradient—requires ATPo passive—water-soluble substances—highlow—acts as a channel- Which wavelengths and colors of visible light penetrate the deepest in coastaland open ocean waters?o Open—blue—about 450 nmo Coastal—green—about 500 nm- Advantages of small sizeo Greater surface to volume ratio, advantage for transporting substances to meet metabolic demands Sphere- SA=43π r2-V =43π r3o The bigger the volume, the greater the need for nutrients- Photoautotrophso Capture sunlight and use it for photosynthesis Plants, some bacteria, protistans (single-celled organisms)Figure:photosynthesis1. H2O split with light energy, O released2. ATP energy drives biosynthesis of glucose from CO2O releasedO releasedO requiredO requiredaerobic respirationaerobic respiration1.glucose degraded to CO2 and H2O2. ETC release energy to drive ATP formationCO, HO releasedCO2, H2O releasedCO, HO requiredCO2, H2O required- Photosynthesis:o12 H2O+6 C O2→ 6 O2+ C6H12O6+6 H2Oo Occurs in chloroplasts 2 outer membranes stroma—fluid interior thylakoids—inner membrane system- capture ad convert sunlight energy to chemical energy reassemble photosynthetic bacteria and could have evolved from bacterial endosymbiontso 2 stages 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- synthesis