Exam 1 (Weeks 1 - 6) Flashcards
When and how did the Earth and oceans form?
Big Bang: ~13 billion years ago.
Solar System: 4.6 billion years ago.
Nebular Hypothesis
A mass of particles of gas and dust slowly contracted and rotated, until the dust eventually settled towards the center of the mass.
How did Earth become density stratified?
Heat caused Earth to melt during initial formation, gravity + buoyancy pulled Fe to the center, less dense minerals migrated to the top and eventually formed the crust.
How did water form on early Earth?
The first proto-atmosphere likely stripped away by sun, gasses released by volcanoes become first atmosphere. Water vapor from the atmosphere condenses into clouds, when the Earth cooled 3.8 billion years ago, the water fell into basins and formed oceans.
Mantle
83% of Earth’s volume, minerals of Fe and Mg silicates, rock = peridotite, large C + H2O reservoir.
Basic Earth Composition
Core: outer core (liquid), inner core (solid), made of Fe + Ni alloy.
The interaction between the liquid and solid core of the Earth causes the magnetic field.
Isostacy
Refers to the way a solid will float on a fluid.
In marine biology, refers to the equilibrium position reached by a block of crust floating on the underlying fluid mantle.
Why are ocean basins lower than the land of the continents?
Isostacy: Since the crust of the ocean is more dense and smaller in volume and thickness, they float lower on the mantle than the surface of land’s crust, which is much thicker and less dense.
Plate tectonics
Unifying theory of geology, describes the discrete movement of the plates in relation to each other, began with continental drift theory.
Wegner’s Evidence of Continental Drift
Shape of the continents, glacial till, fossil distribution, ancient mountain belts, other rock formations.
Where did the water in the oceans come from?
Outgassing from volcanoes.
3 Unique Water Properties
Heat capacity, surface tension, ability as a solvent.
Sensible Heat
Energy required to raise temperature or what is needed to be released to decrease temperature.
Latent Heat
Energy required to change the state of an element (gas, solid, liquid); changes of state always occur under constant temperature.
Density of seawater is controlled by…
Temperature, salinity, pressure.
Surface Tension (Water)
Measure of how difficult it is to stretch or break the surface of a liquid; water has the highest surface tension.
Salinity
Total dissolved solids, varies due to evaporation, precipitation, and rivers.
How is salinity measured?
Via the electrical conductivity of water; principle of constant proportions makes it so that only one ion (Could be Cl/So4) needs to be measured.
Where does salinity come from?
Terrigenous input (rivers, dust, ash), hydrothermal vents, dissolving old sentiments.
Why is the cycle of evaporation and precipitation important to know for the surface of the ocean?
Helps to explain patterns in salinity; higher salinity if more evaporation than precipitation and lower if vice versa.
Atmospheric Circulation Cells and what types are there?
A large circuit of air as warm air rises and cooler air moves to the bottom of the space it exists in; Hadley cells: by the equator; Ferrel: Mid latitudes; Polar cells: found at the cells.
What is the Coriolis Effect?
Observed deflection of a moving object caused by moving frame of reference on the spinning earth; as air warms at equator, rises and moves towards the poles, but is deflected by the movement of the earth + wind; N hem. moves right while S hem moves left.
Intertropical Convergent Zones
ITCZ: Appears as band of clouds consisting of showers and occasional thunderstorms, that encircle the earth towards the equator, where the northeast and southeast winds converge.
Global Ocean Circulation is caused by…
Surface currents caused by wind, other 90% caused by gravity as denser water sinks, the Coriolis Effect modifies current courses, circular pattern left over is called a gyre (clockwise N hem, counter in S hem).
Ekman Transport
What happens when wind blows across the surface of the ocean, which in turn pulls the other layers of the ocean along with it at a less powerful rate the further the water gets from the originally moved surface.
Results of Ocean Currents
Heat transfer from equator to polar regions, weather and climate influenced, distribute nutrients and scatters organisms.
Western Boundary Currents
Transports warm water from low latitudes to higher; ex. The Gulf Stream, Eastern Australian Current, etc.
Core Rings/Eddies
Spin off the western boundary currents and bring warm water north and cold water south; important for heat transport to higher latitudes.
Eastern Boundary Currents
Spin off the eastern boundary currents and transport colder water to higher latitudes to the tropics; Ex. Peru current, canary current, etc.
Upwelling
Wind driven motion of cooler, more nutrient rich water to the surface.
Downwelling
Process of sinking seawater from the surface ocean to the deep ocean, occurs by the accumulation of seawater or by increasing the density of the seawater.
Vertical Distribution of Temperature Zones
Surface: 25-200m depth, Well mixed.
Thermocline: 200-1000m depth, rapid decrease in temperature, may not be present at high latitudes as affected by many factors.
Deep zone: Little change in temperature, cold (-1-3 C), bulk of ocean water with a low average temperature; density increases slowly with depth.
Halocline
Marks the rapid increase in salinity that accompanies the thermocline.
Surface distribution of density…
is minimum at the equator, increases at mid-latitudes, decreases slightly at the poles.
Pycnocline
Marks the rapid increase of density as it accompanies the thermocline, most density increase due to a change in temperature.
Water in the pycnocline is generally…
Very stable, turbulence does not affect this layer.
Greenhouse Effect
Occurs when greenhouse gasses in a planet’s atmosphere prevent the planet from radiating heat back into space.
Light Attenuation
The reduction of light intensity as more photons are scattered or as light is absorbed.
Secchi Disk
A disk used to help measure light attenuation + turbidity; placed in the water until the pattern can no longer be seen, in which case, the depth is measured.
Where is solubility highest?
At higher pressures in colder waters.
Which gas has the highest volumetric concentration in the ocean?
CO2
Nitrogen (As a dissolved gas)
78% of dissolved gas in the ocean, upper layer is usually supersaturated, good for biological organisms, but must be fixed first by something else for use.
Oxygen (As a dissolved gas)
36% of dissolved gas in the ocean, source from photosynthetic organisms living on the topmost part of the ocean or from diffusion from the atmosphere.
Surface = supersaturated, below surface = respiration dominates and decreases available oxygen, deep = slight increase due to less organisms living there and consuming the oxygen to live.
CO2 (As dissolved gas)
15% at the surface, generally increases with depth, very water soluble.
Dissolution rate generally increases with pressure, lower temperature, and increased wind/turbulence, enters deep water via downwelling.
Ocean Acidification
Higher CO2 + H2O leads to the creation of carbonic acid, which disassociates into free hydrogen atoms and bicarbonate atoms.
Absorption of CO2…
Decreases pH (duh), and reduces availability of the carbonate atom for organisms to form healthy shells with.
Carbonate shells are dissolving due to this process of ocean acidification.
Greenhouse Gasses
Water vapor, carbon dioxide, nitrous oxides, methane, ozone and oxygen.
Radiative Efficiency
Ability of a gas to absorb energy.
How do we know the greenhouse effect is caused by humans?
Can use ice to learn about atmosphere of the past, which, when compared to today’s Keeling Curve, does not share the same pattern.
Pelagic Zones
Pelagic: In the water column.
Euphotic: PAR (Photosynthetically active radiation) present.
Disphotic/Twilight Zone: Dimly lit, can see during day, no photosynthesis.
Aphotic: Without light.
Littoral Zone
Beach and extremely shallow water, dominated by continental plants, variable salinity, may contain estuaries, rivers, swamps, etc.
Sublittoral Zone
Open water above the continental shelf.
Shelf Zone
Continental influence, part of photic zone.
Bathyal Zone: Continental Slope.
Abyssal Zone: Abyssal plains.
Hadal Zone: Ocean trenches.
Neritic System vs. Oceanic System
Neritic - near shore environment.
Oceanic - off-shore environment.
Tidal Zones
Intertidal: In the benthic zone, between high and low tides and is exposed twice a day.
Tidal: Always submerged, below the low tide level.
What causes tides?
Gravitational forces of the sun and the moon; the moon’s gravitational effect on the tide is twice that of the sun.
Population vs Community + Ecosystem
Population is a group of the same organisms that live in the same area at the same time. A community is a group of populations of different organisms.
Ecosystem: Community of organisms interacting with each other and their physical environment.
Trophic Pyramid + Levels
TP: Model that describes who eats who.
Primary consumers: Consume producers.
Secondary consumers: Eat primary consumers.
Top consumers/Apex pred: Top of the pyramid, eat whatever.
Chemosynthesis
A conversion of carbon into sugars and nutrients used by bacteria in dark places, use hydrogen gas, hydrogen sulfide, and methane instead of light.
Planktonic/Plankton vs. Nektonic/Nektons
Planktonic: Carried away by the currents.
Nektonic: Good at swimming.
Phytoplankton vs. Zooplankton
Phytoplankton: microorganisms that are photosynthetic.
Zooplankton: heterotrophic microorganisms, may feed on phytoplankton.
Holoplankton
The entire life of the organism is spent in the plankton.
Meroplankton
On a portion of life is spent as a plankton, like fish eggs or mollusks.
Benthic Organisms are…
Epifauna: Live on the surface of the sediment.
Infauna: Live in the sediment.
Bioturbators that mix up the sediment as they burrow.
Epipelagic
Warmest part of the water column and most well-lit, supports primary producers, which supports organisms.
Organisms must stay afloat via increasing buoyancy (air or lipid filled pouches) or increasing surface area for drag to act on.
Diffusion
Solutes move from high concentration areas to low.
Osmosis is…
Movement of water from higher concentration to lower concentration through a semipermeable membrane.
Osmo-conformers
Let their internal concentration vary as salinity does, but can only tolerate very small range of salinity, do not control internal concentrations.
Osmo-regulators
Control internal concentrations, tolerate greater range of salinities, may control concentration through secretion of very little volume but concentrated urine or by having specialized glands to secrete salts.
Poikilotherms
Ambient temperature of the environment dictates their internal temperature.
Regional Endothermy
Some organisms can warm parts of their internal body, like sharks, such as the eyes, brain, and muscles.
Broadcast Spawning
Release eggs and sperm into the water, many organisms time this process with the tide, moon, phase, or water temperature for extra success.
What is the equation for photosynthesis?
6CO2 + 12H2O –(Sunlight)–> C6H12O6 + 6O2 + 6H2O
Primary Productivity
The synthesis of organic molecules from inorganic substances.
Action Spectrum
Utilization of different wavelengths of light by different species for photosynthesis, use of different light absorbing different molecules or pigments in different combinations.
What factors limit primary productivity?
Sunlight, nutrients, water, carbon dioxide.
Nutrients
Substances required by plants, phytoplankton, algae, and actual land plants, resources that can be limited in supply.
Redfield Ratio
Observation that all biomass in the ocean and seawater shows the same ratio of the major elements that are required for photosynthesis. (C: N: P: Si -> 106: 16: 1: 15).
What is N used for in ocean productivity?
Amino acids in proteins, usually most abundant in Nitrate, also available in nitrite, in excretion product recycling from animals in the form of ammonium (taken up the fastest).
Phosphorus (Ocean Productivity)
Found in the ocean as PO4, required for ATP synthesis.
The limiting nutrient of phytoplankton is thought to be which element?
Nitrogen
Where is nitrogen limited in the ocean?
In areas where there is low iron, since bacteria require it for the nitrogenase used to fix nitrogen. Without nitrogen, areas of HNLC (High nutrients low chlorophyll) are created, where there are small amounts of phytoplankton but a large amount of nutrients available.
Sources of Iron
Terrigenous: dust, volcanoes, upwelling in river deposits, ocean ridges or submarine volcanic arches.
Limiting in waters that are away from continents.
Geographic variation of productivity
Continental shelf and open-ocean areas of upwelling are highly productive.
Convergences and fronts often sites of rise of nutrient rich deep waters.
Central ocean and gyre centers are nutrient poor and of low primary productivity.
Phytoplankton Blooms
Eutrophic: high in nutrients and become turbid due to phytoplankton growth.
Oligotrophic: low in nutrients, clear waters.
Algal Bloom: Rapid increase in the amount of algae in the water.
Harmful Algal Blooms
Occur when toxins accumulate due to the rapid growth of algae. May cause wildlife to die, humans to become irritated and ill, and for the environment to decrease in quality of water, habitat, and recreation.
Gross and Net Primary Productivity
Gross: The total amount of primary productivity.
Net: The amount of primary productivity that remains after other organisms make use of the products.
Measuring Primary Productivity Rate
Done by either amount of O2 created or amount of CO2 consumed by photosynthesis; For CO2, use bottles and measure carbon-14 at different depths. For oxygen, use two types of bottles at different depths, one dark and one light to track photosynthesis.
Diatoms
Phytoplankton, simple chains and colonies, encased with unique cell walls of silica called frustule, tiny pores for gas exchange, common, do 25% of C fixation, major O source, some produce domoic acid which is toxic if overeaten, mainly asexual cellular division and become smaller, can become bigger if reproduce sexually or if they secrete an entirely new frustule.
Dinoflagellates
Reinforced by plates of cellulose, have two flagella that help move, phytoplankton, use cell division, abundant in bloom ready water with lots of nutrients, can be toxic (red tide), important for coral growth.
Other autotrophic plankton are…
Coccolithophores: Have intricate shells of calcium carbonate.
Silicoflagellates: Star-shaped internal skeleton of silica with two flagella.
Foraminiferans (Forams)
Calcium carbonate shells, found on sandy/rocky bottom, contribute calcareous material to beaches, have pseudopod for picking up food like phytoplankton, are zooplankton.
Radiolarians
Zooplankton, pseudopods, silica shells, mainly microscopic.
Copepods
Small crustaceans, dominant zooplankton, feed on both phyto and zooplankton.
Salps and Larvaceans
Use mucous nets to capture prey, zooplankton, solitary or in colonies.
Pteropods
Planktonic mollusks, foot separated into two wings, in epipelagic and in deeper waters.
Ediacaran Fauna
575 Ma, first fossil record of animals (soft-bodied), in 555 Ma became quite diverse and abundant enough to leave traces, but died completely out in 543 Ma.
Cambrian Explosion
Happened in Cambrian period (after Ediacaran period), massive event of diversification of animals, rapid increase in amount of taxa.
Evolution of Skeletons
Mineralized hard parts in animals, increases quality and abundance of fossils.
Advantages: protection internally and externally, support large size, prevent from drying out, muscle attachment sites.
Cambrian Substrate Revolution
Large scale changes in sediment lead to sediment bulldozing and benthic dominated seafloors, suspension feeding increased in the benthic lifestyle and the onset of mixground ecology led to better ocean ventilation, suspension feeders finally drove diversification of deposit feeding strategies.
Deposit feeder: sort through sediment to receive organic matter.
Suspension feeder: collect suspended matter from the water.
Causes of Cambrian Explosion
higher level of oxygen, evolution of predation, new niches and territories, new genes and new body plans.
Consequences of Cambrian Explosion
Evolution of skeletons, appearance of larger predators, changes in marine ecosystems.
End of Permian Mass Extinction
Massive reorganization of life, marine life severely impacted, since this extinction, rapid increase in marine diversity, those that survived included bony fish, sponges, corals, gastropods and bivalves, echinoderms.
Mesozoic Marine Revolution
Diversification in cephalopods and ammonites, driven by increased weathering –> nutrients and increase in energetics, likely caused by arms race between prey and predators.
What is the biological pump?
Food/carbon is produced at the surface and then drops to the seafloor.
Phase 1: carbon fixation by primary producers.
Phase 2: Organisms that die either remain at the surface and reintegrate into nutrient cycle or sink to the bottom of the ocean floor.
Phase 3: Dead organisms reach the ocean floor.
3 Mechanisms that drive the biological pump
Gravitational Pump: Sinking particles.
Migrant Pump: Vertical migration of zooplankton during different times of day to avoid predation.
Mixing Pump: Downwelling.
Major Sources of Ocean Sediment
Rivers, dust, volcanoes, biogenic (biological activity), particulate organic carbon = small organic remains that are easily dissolved.
Ooze and ooze types
Calcareous/Carbonate: Derived from organisms that contain calcium carbonate in shells.
Siliceous: Derived from organisms that contain silica in their shells.
Processes that control sediment types are…
Dilution: near continental margins, terrigenous material dilutes biological material.
Destruction: In some parts of the ocean, calcium carbonate shells dissolve and are added to the sediment.
Productivity.
Lysocline and CCD
Lysocline: Depth at which calcium carbonate starts to dissolve.
CCD (Carbonate Compensation Depth): Depth at which the rate of supply = dissolution rate of calcium carbonate and no calcium carbonate can accumulate at the bottom of the ocean floor.
What affects the solubility of calcium carbonate?
Amount of CO2 (more = more solubility), temperature (colder), pressure (higher pressure = higher), upwelling.
Porifera
Sponges: simplest animals, no true tissues, cells are independent with specialized functions, good spatial competitors, incurrent and excurrent canals, asymmetrical.
Cnidaria
Jellyfish, anemones, and coral: no organs, may be polps or medusa, tentacles, one opening.
Ecdysozoa
Includes arthropods and nematodes, ecdysozoans molt their cuticles.
Arthropods
Largest phylum of inverts, all segmented, paired and jointed appendages, all have external skeletons.
Examples: Insects, horseshoe crabs, crustaceans.
Lophotrocozoa
Includes mollusks, annelida, brachipods, and bryozoa.
Mouth develops before the anus, most have a lophophore (filter feeding structure).
Bryozoa
Zoids, colonial, passive filter feeders.
Mollusks
Bivalves like clams, oysters, mussels, scallops.
Active filter feeders, some have autotrophic symbionts.
Axis of symmetry is between the two shells.
Brachiopod
Axis of symmetry is left/right.
Annelida
Segmented worms.
Echinodermata
Marked by radial symmetry.
Includes sea stars, urchins, holothuroids.
What is a neap tide vs a spring tide?
A spring tide occurs during a new and/or full moon, high tides are higher and low tides are lower due to the gravitational forces of the moon.
A neap tide occurs seven days after a spring tide. high tides are lower and low tides are higher, caused by the sun and moon being at right angles to each other, cancelling out the bulge caused by the moon.
How does destruction affect the distribution of sediment?
In some parts of the ocean, calcium carbonate shells will dissolve, leaving behind other types of sediment.
How can iron be supplied when it is limited in the ocean?
Iron fertilization: add the iron to water in the form of iron sulfate, which in turn, causes increase in phytoplankton productivity, which mores more captured carbon, the ocean carbon uptake increases and the sinking biomass of the rest carries carbon to the seafloor where it sits for over 100 years or more.
