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47 Cards in this Set
- Front
- Back
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What is a delta?
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-more or less triangular shaped sedimentary deposit with a distinct distributary system at the mouth of a river
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Three types of deltas:
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1.Wave Dominated(classic or nile-type)-relatively symmetrical with smooth seaward edge
2.River Dominated(lobate or "Bird's-foot")-asymmetrical; irregular seaward edge 3.Tide Dominated(Ganges)-relatively symmetrical with irregular seaward edge |
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Features of Wave-Dominated Deltas
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-large waves
-meso to macrotides -relatively low sediment supply -strong longshore currents -straight shoreline -steep offshore profile -well developed beaches |
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Features of Tide-Dominated Deltas
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-meso to macrotides
-low wave energy -weak longshore current -relatively high sediment supply -offshore profile dominated by shore-perpendicular linear ridges -tidal currents redistribute sediment into shore-prependicular sediment ridges |
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Features of River-Dominated Deltas
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-large, high discharge river
-microtides -relatively high sediment supply -weak longshore currents -gently sloping offshore profile -poorly developed beaches -irregular shoreline |
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What are beaches?
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-unconsolidated sedimentary deposit in transit between the low tide line going landward to some definite change in material or physiographic form, usually a permanent dune line or vegetation
-a dynamic environment that may change locations seasonally or over the long term -The character or nature of a beach is determined by waver energy(changes seasonally), sediment supply (sources?) and sediment type(grain size mostly) |
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Beach profile
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-wave-cut bench or dune scarp
-recreational beach(informal term for entire area divided into: berm, beach face, swash zone, surf zone, longshore trough, longshore bars |
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Composition of Beaches
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-locally available material
-may be coarse or fine: boulders from local cliffs, sand from rivers, mud from rivers, sand from offshore -significant biologic material at tropical beaches |
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Sand movement along the beach
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-perpendicular to shorelin(toward and away)=swash and backwash (rip currents)
-parallel to shorline(up-coast or down-coast)= longshore current |
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Swash and Backwash
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-swash: upwash of water onto the beach (sediment moved toward land). Swash dominates light wave activity causes wider beaches.makes summertime beaches.
-backwash: water returns to the ocean and sediment has moved away from shore. Backwash dominates heavy wave activity causing a narrower beach. stormy weather and wintertime beach. |
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Longshore Current
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-waves almost always approach shoreline at an angle
-angle of incidence and wave refraction causes water and sand to move in a zigzag pattern up and down the beach face in the surf zone -overall motion of water and sediment is parallel to shoreline -Longshore current: movement of water parallel to shoreline -Longshore transport: movement of sediment parallel to shoreline |
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Longshore Transport (Drift)
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-Millions of tons of sediment moved yearly
-Direction of transport can change seaonally due to changes in predominant direction of wave approach -In general, sediment transported southward along Atlantic and Pacific coasts of US |
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What are Barrier Islands?
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-linear, wave-built, emergent sedimentary deposit parallel to coast and seperated from the mainland by a lagoon; an island
-probably formed by the rise of sea level starting about 18,000 years ago -character and type controlled by tidal regime, wave energy, sediment supply and underlying geological structure -protectr mainland from hig wave activity -common on East and Gulf coasts of US |
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Barrier Island Morphology X-section
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-ocean beach
-dunes -back barrier flat -high salt marsh -low salt marsh -lagoon -inlets |
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Tidaly Range and Barrier Island Type
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-Macrotidal (<4)(US West coast):lack barrier islands, shore perpendicular features common, funnel shaped estuaries adn embayments
-Mesotidal (2-4m)(SE US coast): short-stubby barriers, drumstick barriers, wide and frequent intlets -Microtidal (<2)(US Gulf coast): long thin barriers, narrow and infrequent inlets, overwash important |
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Sediment Supply and BI type
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-if sediment is abundant, barrier islands can grow, shoreline moves seaward adn relative sea level appears to fall. Referred to as a regressive barrier and depositional.
-If sediment is scarce, barrier islands appear to shrink, shoreline moves landward, and relative sea level appears to rise. Referred to as transgressive barriers and erosional. |
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What are the basic requirements for life?
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-Space: the marine environment
-Energy: from the sun or food; absorbed or ingested -Nutrients: from environment or food; absorbed or ingested |
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Pelagic Realm
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-Water column from high tide line to deepest parts of ocean
-Horizontal Zones (divisions): Neritic Province (water over continental shelf), Oceanic Province (everything else) -Vertical Zones (divisions): Epipelagic(0-200m), Mesopelagic(200-1000m), Bathypelagic(1000-4000m), Abyssbopleagic(4000m) |
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Benthic Realm
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-bottom; sea floor form highest intertidal to deepest ocean
-Combine horizontal/vertical: Supralittoral(above high tide line; spray zone), Littoral(intertidal zone), Sublittoral(low tide line to edge of shelf <200m), Bathyal(200-400m; slope and rise), Abyssal(4000-6000m; abyssal plains), Hadal(>6000m, trenches) |
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Light Zones
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-Euphotic: (0-100m) with enough light to support photosynthesis; actually probably at least twice this depth
-Disphotic: (100-1000m) with some measurable light where photosynthesis is severely limited -Aphotic: no light |
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Climatic/Latitudinal Zones
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-Tropical: 0-20 degrees
-Subtropical: 20-30 degrees -Temperate: 30-60 degrees -Subpolar: 60-75 degrees -Polar: 75-90 degrees |
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Taxonomic Classifications
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-Kingdom-Phylum-Class-Order-Family-Genus-Species
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Biological Classification
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Old Five Kingdom System
-Monera, Protoctista, Fungi, Plantae, Amimalia |
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Pelagic
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-live in the water column
-planktonic: floaters -nektonic: active swimmers |
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Benthic
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-live on or in bottom
-Epifaunal(mobile or sessile): on the surface of the bottom -Infaunal(mobile or sessile): below the surface; in the bottom |
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Nektobenthos
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-swim or crawl through water above seafloor; closely tied to bottom
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Autotrophic
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-make own food; plants
-by photoautotrophic(photosynthesis) -by chemoautropic(chemosynthesis) |
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Hetereotrophic
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-absorb or ingest food
-by gathering: grazers, predators, scavengers, filter feeders |
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What are nutrients?
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-raw materials; building blocks for organic molecules and life
-basic organic molecules such as sugars, carbs, amino acids, and proteins are made from these five raw materials plus micronutrients -include: hydrogen, oxygen, carbon, nitrogen, phosphorous |
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What controls nutrients?
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-the supply of nutrients is controlled by: proximity to land, upwelling, depth
-Liebig's Law: the growth of an organism or poputlation is limited by the avaliablity of the least abundant nutrient -can extend this principle to all resources including energy and space -the limiting resource varies from place to place and with the seasons |
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Biogeochemical cycling
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-nutrients fixed by producers
-passed onto costumers -some nutrients released to seawater through decompsers -nutrients can be recycled through upwelling |
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Energy
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-most energy comes from the sun(light and heat)
-a small fraction, particularly in the deep sea, is thermal and chemical energy derived from hydrothermal vents and cold seeps -energy and nutrients are combined by the processes of photosynthesis and chemosynthesis into organic molecules |
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Primary Productivity
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-conversion of raw materials into organic molecules
-energy and nutrients are stored in phytoplankton which allows growth and reproduction through photosynthesis -99.9% of marine life relies on photosynthesis for food |
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Photosynthesis
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-light energy input
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Respiration
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-heat energy release
-involves oxidation(burning) of organic molecules to release heat energy for metabolic activity |
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Factors affecting Primary Productivity?
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-avaliabilty of nutrients (Liebeg's Law)
-nutrients come from various sources including river runoff and upwelling -solar radiation in the uppermost surface seawater and shallow seawater |
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Common photosynthetic marine organisms
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-Anthophyta: seed-bearing plants, only in coastal regions, marsh grasses, sea grasses, mangrooves
-Macroscopic (large) algae: kelp, sargassum -Microscopic (small) algae: phytoplankton (ex. diatoms, coccolithophores) -Photosynthetic bacteria: very small; may account for up to half the total photosynthetic biomass in oceans |
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Measuring primary productivity
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-capture plankton
-ocean color: chlorophyll colors seawater, SeaWiFs on satellite |
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Regional Primary Productivity
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-varies from very low to very high depending on distribution of nutrients and seasonal changes in solar radiation
-tropical ocean: consisitently moderate primary productivity throughout the year (nutrient limited) -temeperate regions: depends on the season -polar regions: a single summer peak (energy limited) |
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Consumers
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-eat other organisms
-primary consumer: herbivores -secondary consumer: carnivores |
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Decomposers
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-break down dead organisms and waste products
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Autotrophs
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-primary producers
-first trophic level in nearly all manin food chains |
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Heterotrophs
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-consumers
-higher trophic levels |
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Entrophy
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-loss of a portion of energy as it travels through trophic levels
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Standing stock/crop
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-the amount of biomass at any instant per unit area
-productivity is the total amount of new body material created in a standing crop per unit area per unit time |
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Efficiency
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-how well energy is transferred through the food chain from one level to another
-it is the amount of energy contained in a trophic level that is avaliable for use by the next level compared to the amount of energy supplied to that level -marine food chain efficiency varies from 5% to 40% -the average is 10% |
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3 Food chains
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-Oceanic food chain: leads to the tuna, has 5 trophic levels, low primary productivity and efficency
-Continental shelf food chain: leads to herring, salmon, mackerel, flounder, cod, halibut, 3.5-4 levels, moderate primary production, higher efficiency -Upwelled food chain: leads to anchovy, sardine, and whales, 2-3 levels, high primary production and efficency |
