Marine Bio Midterm Study Guide 1
Marine Bio Midterm Study Guide 1 EBIO 2100
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This 31 page Study Guide was uploaded by Cara Macdonald on Sunday September 25, 2016. The Study Guide belongs to EBIO 2100 at Tulane University taught by Timothy Mclean in Fall 2016. Since its upload, it has received 20 views. For similar materials see Marine Biology in Environmental Biology at Tulane University.
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Date Created: 09/25/16
Learning Objectives Covered: This test will cover the following learning objectives from each lecture (all photos and diagrams taken from lecture powerpoint presentations) 1. Importance of the study of marine biology 2. Learn about aspects of basic biology 3. Learn about life in the largest segment of the Earth’s biosphere: a. How does life exist/how is it different in the marine system? b. How does it inform us about early life on Earth? c. Many products come from the sea d. Ocean as oxygen factory e. Ocean health and human health are interconnected f. Marine environment supports recreation and tourism g. History of marine biology/oceanography 4. Reconstruct the basic structure of Earth 5. Describe the evidence to support “plate tectonics is responsible for the origin and the structure of the oceans basins” 6. Diagram the geological provinces of the ocean 7. Contrast active and passive margins 8. Describe the basic and chemical properties of water (generally) and seawater (specifically) 9. describe the origins of and inﬂuences upon ocean circulation, including the Coriolis effect, global wind patterns, and the great ocean conveyor 10.Diagram the major surface currents, or gyres 11.Contrast the basic tidal patterns 12.Describe basic principles of biology: a. biochemical components of macromolecules photosynthesis, respiration, primary production cell structure and function sexual and asexual reproduction evolution, biodiversity, and taxonomy 13.Identify and describe the most important adaptations of organisms to the marine environment 14. explain the important characteristics and ecological signiﬁcance of marine viruses 15.explain the important characteristics and ecological signiﬁcance of marine prokaryotes (bacteria and archaea), protists e.g. (dinoﬂagellates, diatoms, foraminiferans, radiolarians, ciliates), and fungi 16.describe the most important morphological characteristics,ecological significance, and economic importance of seaweeds 17.summarize the essential steps involved in the sexual reproduction of seaweeds 18.describe and differentiate between the important characteristics of marine flowering plants (seagrasses), salt marsh plants, and mangroves Objectives 1 and 2: Why is marine biology important to study? Learn about the basics of biology ● We don’t know much about the ocean, even though it covers 70% of our earth ● New marine species are constantly being found ● To learn about life in the largest segment of the Earth’s biosphere ○ How does life exist here and how did it originate in the oceans? ■ All organisms start out as a single cell ● Ex. Sea urchin embryology follows the same path of growth as humans ■ Can see how mutating different genes affects development ● Understand w hich genes control which features ● Human counterparts to these genes ○ Ex. studying giant axons in squids allowed us to learn about neurons ● Discovery of cyclins: different proteins that are associated with growth transitions applicable to ALL organisms ■ Learn about early life on Earth by working backwards to recreate what life may have looked like ● Marine organisms can feed us ○ We learn how to grow organisms outside their natural environment ● Have m edicinal benefits ○ Isolate and test chemicals from different organisms ● Can kill us ○ Harmful toxins (e.g. algal blooms) make shellfish dangerous to eat ○ Water may not be potable ● Affect the world around us ○ May be a nuisance e.g. barnacle growth ○ Important positive effects ■ Production of gases affects c loud formation ■ Ocean is an oxygen factory ● Trees and plants on ground produce half the oxygen ● Life in the ocean produces the other half ● Oceans and human health are interconnected ○ Humans enjoy beaches ○ Environment supports recreation and tourism ● History of Marine Biology (formal study) ○ Dates back to Aristotle (the father of marine biology) ○ Disagreed with Plato’s theory of intuitive thinking for discovery ■ Gave rise to scientific method: Observing, testing hypotheses ○ Described over 500 marine species ○ First recognition that cetaceans were mammals ○ Many voyages of discovery: ■ 3 voyages of James Cook in midlate 1700s ■ Charged with mapping, claiming land for england ■ Darwin in the Beagle 183136 ■ Wilkes Expedition, 18381842 ■ Challenger Expedition, 18721876 ● First time boats sent out for sole purpose of oceanographic research ● Discovered over 5,000 species ● Discovered Mariana Trench (deepest part of the ocean) ■ Global Ocean Sampling Expeditions, 20032010 ● Guy who first sequenced the human genome ● Outfitted a sailboat to go around the world sampling water ● Isolated DNA from those samples and sequenced ○ Establishment of dedicated marine stations and labs ■ We now have hundreds of these nationally and internationally ○ Research vessels invented ■ Bathysphere: first dive on August 15th 1885 ■ Kept making new discoveries and designs ● We now have much more sophisticated research vessels ● Designed to go out for days, weeks or months ● Can tag and track animal move 3a: How does life exist in the marine system? 4: Reconstruct the Basic Structure of Earth ● 71% of Earth is covered in water (more than 96% is saline) ○ Technically our planet should be called “ocean” ○ General “basins” make up the separate oceans ■ Used to be only 4, until oceanographers considered different flows of water and characteristics, added a 5th ■ No ocean is really selfcontained ● All mix and become homogenous ■ Southern ocean: ● Slightly warmer ■ Pacific: largest surface area, almost twice as big as Atlantic ● Greatest average depth ■ Atlantic: second largest ocean ● Slightly less deep than Indian ■ Indian: third largest ■ Arctic: smallest ocean ○ Average depth of all oceans is about 4 km ■ Far deeper than the highest point on land ○ Earth exists as layers with different densities and temperatures: ■ Core: ● Very dense, hot and ironrich ● Solid inner core and liquid outer core ○ Swirling motions of liquid outer core thought to produce Earth’s magnetic field ■ Mantle: ● Layer outside of core ● Solid, but very hot and near melting point of rocks ○ Much flows like a liquid, swirling and mixing ■ Crust: ● Outermot and bestknown layer of earth ● Comparatively thin layer, less dense than mantle and core ● Broken up into p lates: ○ Plates are constantly moving→ creation and destruction along the edges ○ Rock remelts as it enters into the Earth, new rock is made on the opposite edge of the Earth ○ Crust of the earth is broken up into many different plates, which can move relative to each other ■ The continents can move on these tectonic plates ○ Main features of plate tectonics: ■ Plates are constantly moving→ creation and destruction along the edges ■ Rock remelts as it enters into the Earth, new rock is made on the opposite edge of the Earth ■ Ring of Fire: site of active volcanoes and Earthquake activity ● These sites line up exactly with the lines of the tectonic plates ○ Evidence of Plate Tectonics: ■ Age of the surface rocks: the rock right along the ridges of plates are youngest (site of creation) ● Become older as you travel away from ridges ■ Sediment accumulation: young rock has had less time to gather sediment ■ Magnetic Strips: ● Magma contains iron elements that slow their movement and harden as it cools ● Dipole ridgelines point toward the magnetic poles of the earth ○ Coincides with the time when the poles of the Earth flipped ● What is created must be destroyed… ○ When two plates come together, one is forced back down into the mantle where the solid rock is remelted ■ Continental plates (less dense) tend to be the “winners” versus oceanic plates (more dense), which are forced down into the mantle ■ This is called subduction ■ When India and Asia collided (two continental plates), the Himalayan Mountains were formed ○ Convection currents beneath the plates assist movement ■ Create the heat necessary for rock building/ destroying ■ Animation: http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_convection2. html ● Structure of the Sea Floor ○ Continental shelf is shallow, submerged extension ■ More like a continent than the ocean floor ■ In some places, continental shelf is very large ● Activity along midocean ridges: ○ Deep ocean environments exist where ridges of tectonic plates exist ■ Newly made rock continuously being regenerated from magma underneath, solidified immediately by cold water ■ Geologic, seismic environments ■ “Chimneys” of rock form and release heat, smoke, toxic materials, etc. ● Sea Floor Spreading: ○ Slabs of oceanic crust separate, form cracks called rifts ○ Releases pressure from the mantle, allowing hot magma to push up through the crust ○ Immediately cools in water, forms midocean ridge ● Sea Floor Spreading and Plate Tectonics: ○ Oceanic and Continental Plates: ■ Lithosphere: layer of crust and uppermost mantle, broken into lithospheric or tectonic plates ■ Asthenosphere: denser, more plastic layer of upper mantle that plates float on ○ Plates spread at about 218 cm per year, creating new lithosphere and destroying old ■ Destroyed at trenches, formed when two plates collide and one dips over the other ■ Subduction: downward movement of plates into the mantle ■ Subduction animation: http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_subduction.ht ml Objective 6: Diagram the geological provinces of the ocean Terms: ● Continental margin: ○ Boundaries between continental and oceanic crust ○ Sediment from the continents accumulates here ■ Can be up to 6 mi thick ● Continental shelf: shallowest part of the margin ○ Biologically richest parts of the oceans ○ Composed of continental crust that presently “happens” to be under water ○ Extends in a gradual, gentle slope ○ Varies in width from less than 1 km to more than 750 km ○ Ends at the shelf break: ■ Slope abruptly gets steeper ■ Usually occurs at depths of 120200 m ● Continental slope: closest thing to exact edge of continents ○ Begins at shelf break and descends down to deepsea floor ○ Submarine canyons channel sediments from the continental shelf to the deep sea ● Continental rise: consists of a thick layer of sediment piled up like an “avalanche” ○ Sediment accumulates at canyon’s base in a deposit called a deepsea fan ○ May extend the continental rise away from fans ● Abyssal plain: nearly flat region of the deepsea floor ○ Rises at a very gentle slope until it reaches the midocean ridge ○ Does include some abyssal hills, plateaus, rises and submarine volcanoes called seamounts ■ Guyots are distinctive flattopped seamounts common in parts of the Pacific ● Some were once islands but are now submerged, partly due to the lithosphere sinking and partly due to rising sea level Objective 7: Contrast active and passive margins ● Active margins: ○ Trenches created when plates collide ○ Zones of intense geological activity, including earthquakes and volcanoes ○ Steep, rocky shorelines caused by the scraping off of descending plate ○ No continental rise ● Passive margins: ○ Much wider shelf ○ Gentle continental slope ○ Lots of continental rise before a byssal plane Objective 8: Describe the basic and chemical properties of water and seawater ● Water: ○ The biological medium on Earth, required by all life more than any other substance ■ Main reason Earth is habitable ■ Earth is only known planet with liquid water ■ Most cells are 7090% water ○ Water molecules: ■ 2 hydrogen atoms +1 oxygen atom ● Covalently bonded: sharing electrons between them ○ Electrons tend to circulate around the oxygen nucleus more than hydrogen ions ○ High electronegativity causes hydrogen atoms to be slightly more positive ○ Oxygen atoms tend to be more negatively charged ● Polar molecules: neg on one end, pos on the other ○ Allows to attract to other polarized molecules ○ Allows to form hydrogen bonds: weak bonds ■ Causes molecules to orient themselves from positivenegative ■ Constantly making and breaking bonds ● Can exist in 3 different states (all can be found on Earth) ○ Ice: ■ Molecules orient themselves into a rigid formation ○ Liquid water ■ Salt added to water prevents formation of hydrogen bonds ● Allows us to cool water below freezing point without freezing it ○ Results in supercool seawater ○ Gas: not much living here ■ Added heat energy breaks hydrogen bonds, turns gaseous ● Presence of hydrogen bonds→ water can store lots of heat energy ○ Stabilizes temperatures ■ Water temp highs and lows moderate along coastline ○ “Universal solvent” (mostly): individual ions (+/) allow themselves to point in a hydration shell of water around atom ■ Eventually becomes dissolved ● Seawater: has low viscosity, allowing quick movement within water ■ Compared to trying to swim through molasses ○ High transparency: allows us to see things suspended ○ High sound transmissibility: sound travels really fast in water, esp salt water (4x faster in water than air) ○ Freshwater vs seawater: ■ Seawater is more dense: has more stuff dissolved in it ■ Freshwater has more heat capacity ■ Seawater evaporates more slowly ■ Seawater has lower freezing point (decreases with salinity increasing) ○ Salinity: the total mass of salt dissolved per mass of seawater ■ For 1 kg of seawater, >95% is just water molecules BUT ● Chloride ● Sodum ● Magnesium ● Sulfate ● All these proportions stay constant ■ Typical salinity of seawater ~35g/kg (3336 g/kg) ● Salinity may also be expressed as parts per thousand or psu (practical salinity units measured using electricity ○ How fast does electricity travel between 2 electrodes?) ■ Rule of constant proportions: ● No matter the salinity, the ratios of the constituents remains the same (within a range) ○ Sources of ions in saltwater: ■ Atmospheric deposition: volcanic action, burning of fossil fuels, etc. puts ions into the air, associate with rain particles, then bring them to the water ● Acid rain: water high in sulfates brought from the atmosphere ■ Weathering: lithogenous sediments coming from continents are broken down into individual ions, which disperse into the water ■ Benthic seepage: water dissolves substances and brings them back to the surface ● Water molecule: input is evaporation, residence time is thousands of years ● Salt ion: input is formation of salt deposit/salt spray, accumulate over millions of years ○ Has the ocean always been so salty? ■ NO: t he accumulation has occurred over millions of years ■ Our cells contain just slightly less salt than the oceans do today, so we can infer that the first cells contained slightly less water than ours do today ● Knowing that all life began in the ocean ■ Highest salinities in areas with more evaporation than precipitation ● Freshwater inputs near coastlines drive salinity down ■ Density of seawater depends on: ● Primarily temperature: as you warm things up, they tend to spread out and decrease density (colder temps → denser water) ● Secondarily, salinity (more so in estuaries): higher salinity → denser seawater ● Thirdly, pressure (only in the ocean): denser seawater at the bottom of the ocean than the top (higher pressure→ denser water) ○ How does temperature distribute across the surface of the oceans? ■ Higher at the equator, gradually cools down toward north or south pole ■ Surface: around air temperature (between 2025 degrees C) ■ Thermocline: shift of temperatures as depth changes ● Average temperature in the ocean ~3.5 degrees C ○ How does salinity distribute? ■ Changes across the halocline from ~34.535.5 ● Pretty constant throughout the oceans ○ How does density distribute? ■ Density changes across pycnocline: increases with depth ● Seawater also contains dissolved gases ○ Contain nitrogen, oxygen and carbon dioxide ○ Per 1 kg seawater: ■ N2 ~0.014g ■ O2: 0.005g ■ CO2: 0.09g ○ Dissolve in the air, go back and forth between water and air ○ Oxygen: only slightly soluble ■ Most stays in atmosphere or quickly returns to atmosphere ■ Anoxic zones: low concentration causes dead zones in organisms ● Fish kills, death of invertebrates ■ Strongly influenced by biological activity ● Bubbles up off of vegetation/photosynthetic sources ○ Carbon Dioxide: highly soluble ■ Reacts with water to create bicarbonate→ carbonic acid → carbon buildup at the bottom of the oceans ● Oceans becoming acidified as a direct consequence of global warming ● Acidic environment dissolves shells → organisms that rely on shells die → predators die → travels up the food chain ○ Also contains natural parts of the Earth’s crust that dissolve into the ocean: ■ Silica ■ Lead ■ Iodine ■ Manganese ● Colors in water have different biological implications ○ Which wavelengths organisms can see, photosynthesise with ● Water Pressure: ○ Increases with depth ■ The pressure at the surface is one atmosphere of pressure ● For every 10m, add one more atmosphere ■ Organisms have evolved to live at different depths: ● Some live 4,000m+ below surface ○ They have evolved and adapted to do so ○ If they were to come up, they would expand with decreasing pressure ○ CHANGE i n pressure is more detrimental than pressure itself most species cannot survive a significant pressure change ■ Ex: grouper has a swim bladder that will expand greatly when it comes to the top of water (deep sea fishing) ● It may be unable to compress bladder back down and swim to the bottom ■ Other organisms don’t swim down bc they can’t withstand the increase in pressure ○ Most organisms don’t do a lot of swimming up and down ● Sound in water: ○ Speed of sound travels much faster in seawater than in freshwater or the air (4x quicker) ■ Waves of sound travel faster between denser particles in salt water (waves travel from particle to particle) ■ It is difficult for us to determine the direction of sound ■ Organisms have special adaptations to be able to orient themselves with the direction of sound Objective 9: Describe the origins of/ influences upon ocean circulation ● Movement of water: ocean is always moving ○ Significant driver of circulation within the oceans: wind patterns ■ Blowing of wind across the surface of the water (may be winds blowing all the way across the world radiating onward) ○ Winds a nd currents are subject to the oriolis Effect: ■ If the earth were not spinning and you traveled (on airplane) directly north to south, you would move in a straight line. However since the earth IS spinning beneath you, your pinpoint destination is moving → you must correct your course to compensate for Earth’s rotation ■ Wind/water deflected to the right in Northern hemisphere, left in Southern hemisphere ● What generates the wind? ○ Differential heating of the earth from solar energy ■ Hot air rises up, tends to hold more water ■ As it starts to cool down, it releases held water and causes storms ■ Hot air cools and disperses from the equator, cool air comes toward equator to replace it and is heated up ■ Does NOT move North to South, moves in a general westerly direction ○ Cycle cells of wind circulation are c onvection currents: ■ 3 convection cells in Northern hemisphere, 3 in Southern ● 6 different convection cells (each pair moving in opposite directions) Objective 10: Diagram the major surface currents, or gyres ○ Wind blowing in a certain direction pushes surface current away from it in the same direction ■ (surface currents driven by wind and ultimately heat energy of sun) ■ Water is also subject to the Coriolis effect and deflects slightly away from the direction of the wind ● The stronger the wind, the more effect on the water’s direction ■ Ekman spiral: opposition in direction from the coriolis effect versus air movement ■ Ekman transport: 90 degrees to the right of wherever the wind is blowing ● Water tends to compromise between these perpendicular angles and move at about 45 degrees angle ● Vertical movement of water: ○ Usually, water will s tratify: ■ Will layer by temperature: warm water at surface, cold water deeper, thermocline between ■ When strata are stable (from stable temperature) water will stay stratified ■ In temperate regions, warmer strata will cool and move downward ● Decreased thermocline ● Most oxygen exists at the top, life and nutrients at the bottom. Water moves to bring nutrients to the top and oxygen to the bottom ■ In the summer, stratification is stable and consistent ■ In the fall, stratification begins to break down as temperature decreases ■ In the winter, surface water becomes very cold and more dense, sinks to the bottom→ Downwelling (o verturn): ■ Causes a slight circulation as wind comes up one side of the wave and down the other side ■ Higher waves→ energy transferred deeper down into water ○ Size of a wave is directly related to windspeed itself: ■ The FASTER the wind or the LONGER the wind has been blowing is directly related to wave size ■ Wind fetch: the longer the wind has been blowing gives it more distance to interact with the water ● Expect greater rates of erosion at the top where fetch is higher and closer to wind ● Size of waves increase with: ○ faster/longer the wind blows ○ Greater fetch: the area of open water over which the wind can blow ■ Open ocean has tremendous fetch ■ Where wind is actively blowing, wind pushes crests into sharp peaks to create seas” ● Causes waves to become irregular, choppy ● Energy propagates down into the water column ■ Where wind is no longer actively blowing, waves still exist as energy is translated ● Waves become smoother, more regular ■ Where waves encounter some land mass, energy is forced up from the water column ● Top of waves b reak to create surf ● Waves are larger the longer they have been traveling across the ocean, gaining energy ○ Tides: the rhythmic rise and fall ■ We go through revolutions of high and low tide throughout the day ● Bulges of water: ○ Caused by the moon, which pulls the water toward it using gravity ○ ALSO caused by the moon’s and the earth’s “dance” ■ Imagined on a fulcrum: to get to the point of balance, must move the fulcrum to Earth ● The Earth moves as the moon rotates around it ■ Centrifical force pushing the earth to the opposite side of the moon, resulting in wo bulges: ● One on the moon side, one on the opposite side ○ Much like the moon and the Earth, the Sun a nd the Earth have a dance too ■ Gravitational pull from Sun creates much smaller bulges ■ When the sun, Earth and moon are all lined up (on the new monthly moon), we get VERY high tides ● 7 days later, the bulges of the moon are perpendicular to the bulges of the sun, and they partially cancel out ● 7 days later, everything is in line and we get spring tides again ■ High tides don’t occur at the same time every day; not on a perfect, 24hour cycle ● First high tide occurs when t=0 (midnight) ● 6ish hours later, the moon causes a low tide ● 6 more hours, high tide again ● 6 more hours, low tide again ● By the 24th hour, it is not quite high tide (because the moon has moved around the earth: 1/28th of its orbit around Earth, about 50 extra minutes) ■ Most places have to high and two low tides a day semidiurnal (East coast) ● If the high tides are unequal in amplitude, mixed semidiurnal (West coast) ● Rarely, a single high and low tide diurnal (places like the gulf of Mexico enclosed body of water where winds are different) ■ Geographic features, spins/orbits of celestial bodies, weather and seasonal climatic fluctuations may affect the rhythmic rise and fall of sea level at shore lines ■ Tidal range: refers to difference in water level between successive high and low tides ■ Spring tides: when sun and moon are in line with each other, their effects add together, creating a much larger tidal range ■ Neap tides: when the sun and moon are perpendicular to each other, their effects partially cancel out, creating a much smaller tidal range ● Chemical and Physical features of Seawater and the World Oceans ○ Important properties associated with seawater/oceans ○ Effects of wind: ■ Surface currents (influences of the Coriolis effect) ■ Creates waves ○ Thermohaline circulation and the great ocean conveyer ○ Rhythm of tides *Practice quiz*: How might measurements of salinity, nutrient levels, D.O., surface water temperature and sea water density might differ during winter and summer? Assign relative values to each paramaterrelative values ● Salinity: lower in the summer when freshwater from the Gulf of Mexico dilutes into the Mississippi; higher in the winter ● Nutrient Levels: lower in the winter, higher in the summer because of fertilizers drifting downstream ● Dissolved Oxygen: intermediate in the winter, low/none in the summer (“dead zones”) ● Surface temperature: h igher in the summer ● Seawater Density: dependent on temperature and salinity → lower in the summer when things expand, has a lower salinity Objective 12: Describe the basic principles of biology ○ Cells are 7095% water, the rest made up by: ■ Carbohydrates ■ Lipids ■ Nucleic acids ■ Proteins ■ Others ■ **All products of photosynthesis in plants** ○ Element: substance that cannot be broken down into other substances by chemical reactions ■ Oxygen, Carbon, Hydrogen and Nitrogen make up 96% of living matter ■ Require some amount of trace elements like iron, magnesium, etc. ○ Compound: a substance consisting of two or more elements in a fixed ratio ■ Sodium chloride=Sodium: Chlorine 1:1 ○ Biomolecules: cells are 7095% water, and the rest: ■ Mostly carbonbased molecules that came from CO2 in the air around us ● Through the processes of some photosynthetic organism that was either directly or indirectly consumed ■ When we go from small, simple molecules to very complex molecules, energy is required to make/break bonds, store fats, anabolism/catabolism ● Enzymes help us break molecules down during digestion so we can use the energy released ■ Carbohydrates: sugar ● Monosaccharides: one sugar molecule ● Polysaccharides: many molecules in a chain ● BOTH are almost exclusively C,H and O ● Functions: ○ Quick source of energy (if it’s not a carbohydrate, we make it into one for fast energy) ○ Energy storage (starch and glycogen) ○ Structural elements (cellulose and chitin) ■ Proteins: long chains of amino acids ● May be coiled into secondary structures ○ Can be further manipulated into tertiary structures ● 3D structure allows for a variety of functions, ultimately all related to structure ○ Mostly C, H and O; also N and a little S ■ Lipids: very diverse fats, oils, phospholipids, and steroids ● Mostly hydrocarbons (maybe P, O and/or N) ● Provide A LOT of energy ● Make up most of our membranes (phospholipids) ● Store energy and can be used for energy (fats/oils) ○ For many organisms, the priority is to store layers of fat as blubber, insulation, etc., or bouyancy (energy storage) ○ Also waterproofing, major membrane components (phospholipids, cholesterol) and chemical messengers (hormones) ● Steroids are chemical messengers that have an important role in sexual development ● Extremely hydrophobic separate themselves from water ■ Nucleic Acids: DNA and RNA ● Almost exclusively C, H, O, N and P ● Functions: ○ DNA: stores information and directly synthesizes to RNA ○ RNA: transmits information to ribosomes, translated or assists in translation, regulates gene expression, riboenzymes ○ What fuels life? Much of it is about breaking things down and extracting energy ■ ATP is how we capture energy: ● The ATP cycle: ● Most organisms get energy from the sun: ○ Directly: Autotrophs (producers) feed themselves ■ Photoautotroph feeds itself through light ■ Producers of the organic matter we consume ■ Bottom of food chain: all energy in all ecosystems is ultimately derived from the sun ■ Include plants, (terrestrial and aquatic), algae (macro and micro), certain other protists and some prokaryotes ● Harmful agal blooms made up of c yanobacteria (singlecelled organisms) ■ All collectively produce at least half the gas in the atmosphere ■ Can assume photosynthesis ● Solar energy trapped in pigments of chlorophyll ● Creating ATP, generating Oxygen as a waste product ● Bring in carbon dioxide as carbon source ■ Marine plants have huge amounts of water, CO2 and light (if clear water close to surface) ● Requires sunlight, energy, CO2, water and other required nutrients (N, P, Si usually as silica SiO2, Fe) ○ Indirectly: Heterotrophs (consumers) ■ Heterotrophs eat autotrophs (or other heterotrophs) ■ Rely on autotrophs for energy and/or oxygen ■ Tops of the food chain ■ Undergo process of respiration: ● Glycolysis: series of reactions to break down glucose ● Aerobic respiration: in the presence of Oxygen; much more efficient in making ATP ● Anaerobic respiration: cells may utilize fermentation ● Photosynthesis is to building as respiration is to breaking down ○ Everything respires (including plants) but only plants photosynthesise ○ Balancing of building stuff up (photosynthesis) and breaking stuff down (respiration) ■ Usually photosynthesis rates are faster than respiration rates, which results in a net increase in organic matter (primary production→ allows for growth ) ○ It all comes down to cells: ■ The basic structure of life ■ All cells have 4 characteristics: ● Genetic material (DNA) ● Cell membrane (semipermeable membrane) ● Cytoplasm ● Ribosomes ■ Prokaryotic cells: evolved before the evolution of a nucleus ● Most primitive/ancestral of all known forms of life ● Most have cell wall ○ All have nucleic acid, cell membrane, ribosomes ■ Eukaryotic cells: ● Struturally complex w multiple organelles including nucleus ● Extensive endomembrane system ● Structural and content differences: plant cell versus animal cell ○ Plant cells have cell walls for extra support; animal cells lack ● Lots of singecelled eukaryotes in the world ● Reproduction: how do aquatic organisms make more of themselves? ○ Asexual reproduction: primary way singlecell organisms reproduce (cell division) ■ Individual can reproduce itself without the involvement of a partner ■ Offspring inherits all genetic information from parent are exact copies ■ Multicellular organisms reproduce this way too, through: ● Fission: s plit in half to create 2 smaller versions ● Budding: instead of dividing, parent develops small growths that break away and become separate individuals ○ Sexual reproduction: most multicellular and some unicellular organisms use ■ New offspring arise from the union of two separate cells, called gametes ■ Organisms have special germ tissue of cells capable of dividing by meiosis (produces two haploid cells with copies of half parents’ chromosomes) ■ Most organisms’ gametes are one of two types: ● Eggs (female gametes) ● Sperm (male gametes) ■ Sperm and egg fuse to form a zygote t hat is 2n ● DNA from both parents ● Recombination produces diversity of unique offspring ● Evolution: ○ Fueled by process of natural selection ■ Best adapted individuals produce most offspring ■ Pass favorable genetic traits down ○ Every population is constantly adapting to its environment and being faced with new challenges ○ An endless process of extinction and adaptation Objective 13: Identify and describe the most important adaptations to marine life ● Adapting to a marine environment: ○ Several changing factors to adapt to: ○ Temperature ■ Temperatures very low at the bottom of the ocean ■ Some organisms are heattolerant ● Bacteria living in hot springs/geysers ■ Also affects pressure ■ Two schemes categorize organisms by how they regulate (or don’t) body temperature ● All organisms generate metabolic heat. Some can retain and maintain the heat (like us), while some organisms cannot retain their heat and rely on an outside source (like lying in the sun) ● Ectotherm: coldblooded ● Endotherm: warmblooded ● Poikilotherm: body temperature varies ○ All ectotherms are poikilotherms ○ Some endotherms: large sharks, tunas and billfishes ■ Allows them to swim faster when muscles are warm ● Homeotherm: maintains a very stable body temperature ○ NO ectotherms ○ Some endotherms: mammals and birds ○ Salinity ■ How do marine organisms cope with solute differences between themselves and their saline, aqueous environment? ● Osmoconformers: ○ No active control of osmolyte/water balance ○ No internal concentration varies with surrounding osmolarity ○ Most can only tolerate a very narrow range of salinity ● Osmoregulators: ○ Active control of their internal osmolyte concentrations ○ Can generally tolerate a wider range of salinities than osmoconformers ○ Mechanisms of osmoregulation: ■ Actively matching the internal osmolyte concentration to the external concentration ● Sharks, rays, skates are capable of this ● Increase the osmolyte concentration of their blood by adding urea to it ○ Bullsharks are able to regulate themselves much better than other sharks ○ Dunaliella sp. Produces lots of glycerol in its cytoplasm, increases internal osmolyte concentration, thrives in salt ponds ■ In other fishes that aren’t cartilagenous (sharks/ rays) can maintain an internal osmolyte concentration not equal to the eternal concentration ● Water loss by osmosis through gills and skin ● Make up for this by drinking lots of seawater have a physiology that filters out ions in the water ○ OR they have a very concentrated urine ■ Specialized salt accumulating glands or cells to get rid of excess salt ● Tear ducts in turtles ■ Plants and some algae have cell walls to impede swelling ● So even in a hypotonic solution, it can only absorb so much water Objective 14: explain the important characteristics and ecological significance of… ● What do we mean by microbes? ○ Organisms less than 100 microns (cannot usually be seen with the naked eye, requires use of a microscope) ■ Viruses/bacteriophage ■ Prokaryotes ■ Fungi ■ Protists ■ Multicellular eukaryotes ○ Why do we care about them? ■ Can live in all oceanic habitats they are literally everywhere ■ Are the most numerous group of organisms on the planet highly abundant ■ Are capable of many different types of metabolism ● bio/geochemical ● animal/plant/human health ● Viruses: obligate, intracellular parasites ○ All forms of life are infected by viruses: exist as discrete particles but can have HUGE impacts on all forms of life ■ Rely on living things in order to reproduce themselves ■ Infect a cell, use its machinery to create new copies of its own genome ■ We are discovering new viruses frequently ● Hundreds and hundreds of different viruses that humans are susceptible to ● 95% of particles found are viruses, but still only have a small biomass ■ Most widespread family of viruses: herpes virus ● 8 human herpes viruses ● Almost all organisms are susceptible to some form or another ● Not fatal to humans, but may be in other organisms ○ Vary in size, shape, genetic content, genome, host range (specificity of infection), etc. ■ Some have very very small genomes with 45 genes, some have 200300 ■ Every virus is specific to a certain cell type ● Cannot just infect any cell it finds ○ Whether or not viruses are “living” is moot ● Ecological roles in the Oceans: ○ 1. Part of a microbial loop (like a food chain) ○ Some of the particles that aren’t eaten get released into the water, dissolve into organic matter ■ What happens to this? ● Phytoplankton don’t eat ● Grazers don’t eat ● Heterotrophic bacteria are able to recognize and make energy by consuming these “dead cells” ○ Virus abundance is important for contributing to this loop ○ When viruses infect a cell, they cause it to lyse and release its material, which contributes new food to the microbial loop ■ Produces Dissolved Organic Matter (DOP) and Particulate Organic Matter (POM) ○ 2. Cause disease to marine organisms, waterborne and seafoodborne disease to humans Objective 15: prokaryotes, protists and fungi ● Prokaryotes: 2 domains, bacteria and archaea ○ Most ancient forms of life, singlecelled, nonnucleated organisms ○ 3 shapes of bacteria: ■ Cocci (round coccus, diplococcus, streptococci, staphylococci), bacilli (bacillus, diplobacilli, streptobacilli) (rod) or other shapes ■ Structurally simple, with few shapes ■ Few, if any organelles ■ Yet, most metabolically diverse organisms on earth ■ Most have cell walls made of peptidoglycan (not cellulose) ■ Asexual reproduction (binary fission) ○ Virus particles: 10^7 viruses/ml; bacteria: 10^6 cells/ml ■ These numbers are pretty much uniform throughout the ocean ■ How diverse are these numbers? ● Samples and sequencing experiments found at least 18,000 species highly abundant, highly diverse ○ How can there be so many? What are all of these bacteria doing? ■ If you win, you lose: if one species is more abundant than another, it’s more likely you will be infected with viruses ● Helps to limit any one species from predominating ■ They are playing important roles in the earth’s biogeochemistry ● Ex carbon and nitrogen cycles, symbiotic relationships, biotransformation and remineralization ○ Special group: cyanobacteria ■ Formerly known as bluegreen algae, because of their green color due to photosynthesis ● Don’t have a nucleus, so they are prokaryotes that are photosynthetic ■ Ancient fossilized (sometimes still alive!) in stromatolites (up to 3 billion years old) ● May still be actually photosynthetic ● Responsible for creating the first oxygen in our atmosphere now ■ Highly abundant and can be found everywhere (freshwater, saline water, land, etc.) ● Prochlorococcus is probably the most abundant type in the ocean ■ Thought to be the cells that ultimately became the chloroplasts in eukaryotic cells ■ Important nitrogen fixers, especially in the ocean ■ Can cause highly toxic harmful “algal” blooms and dermatitis ● Archaea: ancient, singlecelled, nonnucleated organisms ○ Originally found in only “extreme” environments, but later shown to be common in marine environment (symbionts with other marine organisms) ■ Hot springs vibrant color is different species of archaea. thermoacidophiles ■ Great salt lake: extreme halophiles ■ Sewage: methanogens (a lot in our stomach, gets excreted and ends up in sewage facilities) ○ Are now known to be much more widespread, not just in extreme environments ● Photoautotrophs: photosynthetic ● Chemoautotrophs: can synthesize food by using the chemicals around them ● Heterotrophs: bacteria which can’t make their own food, rely on others Marine Microbiology: unicellular eukaryotes ● Microalgae and protozoa→ P rotists: 10^310^4 cells/ml ● Pure phototrophs: g
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