FINAL Flashcards
What is the average salinity of the ocean?
Average salinity is usually considered to be 35 ‰.
What is a thermocline?
where wave and current action no longer mix the waters.
What are surface currents run by?
Wind
What causes spring tides?
When the Sun and Moon are aligned with respect to the Earth, their bulges will overlap and be additive (new/full)
What causes neap tides?
When the Sun and Moon are at right angles with respect to each other, their bulges will be offset and will be subtractive (wax/wane)
What are semidiurnal tides?
two high tides and two low tides of relatively equal height each day
What are diurnal tides?
only one high and one low tide each day
How do you find the wave base?
depth equal to half the wavelength (determines surface mixing)
What energy sources cause waves?
Wind, storm surges, tsunamis, Seiches
What is fetch?
the distance that wind blows over open water, and thus the distance over which wind “forces” the formation of larger waves
What is shoaling?
If the bottom becomes shallow enough that the wave base is below the bottom, the wave is said to be…
What is the intertidal zone?
That area of the shore that is exposed to air during low tide, and is submerged at high tide.
Why is the intertidal zone stressful?
they must survive, sometimes for many hours, exposure first to air and then to water.
What is zonation?
discrete areas inhabited by different groups of organisms. In the intertidal zone these areas appear as relatively horizontal bands parallel to the shore
What are abiotic factors? List some.
Not caused biologically (temperature, desiccation, anoxia, etc.)
What are biotic factors? List some.
Caused biologically (competition, predation)
What is the rocky intertidal?
Rocky slopes, faces, and bouldersGenerally stable in the face of wave action Usually has a complex 3-D structure, allowing patchy distribution of organisms
(i.e., sun-exposed and shaded areas, wave-exposed and protected areas;
more or less water flow, etc.)
c. Since organisms can’t burrow into rock (generally), they must cling to the
surface, or to other organisms, or find protected spots
What is hypoxia?
Causes metabolic depression and death due to lack of oxygen
What is UV exposure?
UV radiation, DNA damage
What is dessication?
loss of water due to exposure to air during low tide
What is wave action?
Waves
What is predation?
Getting predated (usually eaten)
What does it mean to be sessile?
Being unable to move by themself
What is competition?
Competing for space
What are the zones of the intertidal?
Supralittoral, midlittoral, infra littoral, subtidal
What is the supralittoral fringe?
Area affected by wave spray, but rarely by high tides; borders the “supralittoral” (i.e., terrestrial) zone
What is the midlittoral zone?
Broadest area of the intertidal, and is often subdivided into upper midlittoral, lower, etc.
What is the infralittoral zone?
Usually covered by sea water, except during spring tides
What is the subtidal zone?
the rest of the ocean (never exposed to air)
What is broadcast spawning?
external fertilization
What is synchronous spawning?
coordinate release of gametes in time
What are Lecithotrophic larvae?
depend on a large yolk sac provided by the mother. They don’t need to rely on the external environment for food, but when the yolk is consumed, the larva must metamorphose and settle, whether it is in a good
location or not
What are planktotrophic larvae?
have very little yolk, and must feed
themselves, consuming other plankton in open water. They are reliant on good environmental conditions (i.e., abundant prey), but can delay metamorphosis when necessary
What is the intertidal zone on a sandy beach called?
Foreshore
What is the Upper portion beyond the reach of the waves on a sandy beach called?
Backshore
What are infauna?
Burrowing organisms (crabs, clams, worms)
What are meiofauna?
extremely small animals that live within the
interstitial water of sandy sediment (live in between sand grains) like flatworms, annelids, etc
What is an estuary?
the area where a freshwater system (stream or river) meets the ocean, and the flow is slow enough that organic material settles to the bottom to form sediment.
What are salinity gradients?
Estuary waters can vary from
the salinity of sea water (35‰, or even higher depending on evaporation) to fresh water
What does brackish mean?
Water that is intermediate in salinity between seawater and freshwater
What is a salt wedge?
Salinity gradients with depth can develop when in-flowing freshwater (less dense) over-tops a lower layer of salt water
What is euryhaline?
organisms that can survive large variations in salinity
What is stenohaline?
organisms that can survive no variations in salinity
What are salt marshes and where are they found?
found in estuaries in temperate and sub-polar regions, wherever estuaries deposit organic material on a shallow bottom
A salt marsh is an area of coastal grassland regularly flooded by salt water.
Salt marshes are defined by emergent vascular plants, which stabilize sediment and form a transition from aquatic to terrestrial habitats.
What is zonation?
Distinct sections of a zone (i.e. intertidal, estuary, etc)
What is halophilic?
Salt-tolerant plants
What are mangroves and where are they found?
Mangrove forests are found along tropical coastlines, forming dense and diverse stands in tidal areas with little wave action
What are aerial roots?
grow from the trunk
down into the water, and finally into the sediment
What are pneumatophores?
specialized roots that
grow up from below, and act as snorkels, reaching the air and providing oxygen to the roots in the anoxic sediment
What is vivipary?
germination of the seed while still attached to the parent plant
Who survives high wave action better in an estuary, salt marshes or mangroves?
Salt marshes
What does oligotrophic mean?
with very low nutrient levels – it is the opposite of eutrophic
What are some cues for broadcast spawning?
temperature (which often controls the month for spawning, tidal height or moon phase (which often controls the day of spawning), and sunset (which often controls the hour of spawning).
What are zooxanthellae?
intracellular, photosynthesizing symbiotic dinoflagellate algae that work with reef-building corals
What is coral bleaching?
environmental conditions in which the zooxanthellae apparently become a cost to the coral host
What are the main causes of coral bleaching?
most commonly associated with high temperature, but can be caused by other stresses such as disease, sediment, or pollution/toxicity
What do reefs need?
20 degrees C, higher than 50m below sea level, fully saline, low level of sediment, middle level nutrient levels,
What is a fringing coral reef?
Reefs that grow off the side of the coastline (most common)
What is a barrier coral reef?
The reef will continue to grow upward, but a lagoon will form between the reef and the shrinking island.
What is an atoll?
older volcanic islands finally sink beneath the sea surface, due to subsidence and erosion. The original fringing-then-barrier reef continues to grow upward, forming a ring outlining the ancient shoreline of the now-sunken island.
What are consolidators?
organisms who through their own growth tend to stabilize calcium carbonate exoskeletons of corals, and therefore stabilize reef structure
What are bioeroders?
organisms that erode the mineral matrix of the reef
What are seagrasses?
angiosperms (flowering plants) that have re-colonized marine habitats. They are NOT ALGAE NOT SALT MARSH GRASSES (not even grasses lol)
What are epifauna/epiflora?
organisms live attached to seagrass blades, or attached to organisms that graze on seagrass blades
What is kelp?
macroalgae, characterized by holdfasts and a thallus (body), supported in the water by gas-filled floats (pneumatocysts), used as a source of food/cover
What is the Coriolis effect?
causes masses moving relatively long distances across the
surface of the Earth to follow curved, rather than straight, paths (think hurricanes)
What is thermohaline circulation?
Changes in surface water density occur at higher latitudes, as both the temperature and salinity change
What is the Ekman spiral?
The Coriolis effect intensifies upwelling through a transfer of wind momentum into deeper waters
What is upwelling?
The moving of deeper water to the surface
What is the photic zone?
upper layer of the ocean in which sunlight occurs
What is the euphotic zone?
depth to which enough light penetrates to allow photosynthesis. This can vary according to water clarity, but is usually down to ~100 to 200 m.
What is the dysphotic zone?
still light here, enough for vision, but not enough for photosynthesis (also variable depending on location, but ~ 1000 m deep).
What is the aphotic zone?
no sunlight at all (but bioluminescence is important)
What are plankton?
organisms that are not able to swim against the current, and so tend to drift in surface waters.
What are nekton?
Organisms who can move independently and freely
What are phytoplankton?
autotrophic – they produce food via photosynthesis. Because of this, they must stay near the surface, well within the photic zone
What are zooplankton?
heterotrophic – these are animals that graze on phytoplankton or prey on other heterotrophic plankton
What are haloplankton?
organisms that spend their entire life cycle as plankton – most phytoplankton are holoplankton
What are meroplankton?
organisms that spend only part of their life as plankton – think of all the invertebrate and fish larvae we have discussed, which ultimately metamorphose into non-planktonic adults
What are the types of phytoplankton?
Diatoms, dinoflagelletes, Coccolithophores, cyanobacteria
What are the most important nutrients in the marine realm?
nitrogen, phosphorus, and iron.
What is the compensation depth?
After reaching maximal productivity, photosynthesis decreases with depth until the amount of carbon reduced matches that being consumed by respiration
What is DOC?
DOC (dissolved organic carbon) is composed of reduced carbon containing compounds in
solution.
What is the microbial loop?
These bacteria capture “lost” (i.e., dissolved) reduced carbon, and can also release more DOC by “attacking” organic particles – up to 70% of bacteria are found on particles, rather than free-floatin
What is POC?
living cells, or particulate organic carbon (POC)
What are some protists?
Foraminifera, radiolarians, tintinnids
What are some holoplankton?
Jellies, comb jellies, copepods, krill
What is the the scattering layer?
The dense layer of organisms can be detected via sonar
How does fin propulsion work?
undulatory waves of their fins, on either side of the body, to propel themselves
ii. Propulsion can be in either direction (unlike many vertebrate swimmers)
iii. Fin propulsion is used most often for slower, longer-distance travel
How does jet propulsion work?
rapid contraction of the
mantle cavity to expel water with force through
the “funnel”
ii. The funnel can be pointed in multiple
directions, giving control over direction of
travel
iii. Jet propulsion is mainly used for rapid attack or
escape.
How does fin propulsion work?
Faster-moving fish use their caudal (tail) fin almost exclusively, and the fastest have very little movement of the rest of the body anterior to the caudal fin
b. More maneuverable fish (think coral reef fish) may use a combination of fins, especially pectoral fins (like flapping wings) or dorsal + anal fins. What they gain in maneuverability they lose in speed.
What is the Reynolds number?
ratio of inertia to drag, Bigger animals have a higher Reynolds number, and inertia is more important to them.
What is countershading?
white (or better yet, silvery) on the
bottom, dark blue or green on top, to camoflauge with surrouding open ocean
What is marine snow?
gentle sinking material from the euphotic zone, such as dead plankton, feces, and mucus nets trapping bacteria etc.
What are whale falls?
rare but large sources of organic material that fall quickly to the sea floor (they don’t have to be whales – anything big and rapidly sinking)
Where do hydrothermal vents usually sit?
above magma chambers that extend close to the sea floor – these magma chambers provide the energy that heats the water, away from the mid-ocean ridges, at hot spots on the ocean floor
What is thiotrophic?
“sulfur-eating,” i.e., these bacteria can metabolize hydrogen sulfide, H2S.
What is methanotrophic?
“methane-eating”; these bacteria metabolize methane, CH4.
What are cold water seeps?
reduced compounds (usually
organic, such as methane) are leached from underlying formations, usually more slowly than what we see at hydrothermal vents.
What is the Bathyal zone?
200m–4000m
2. ~ 5% of ocean floor
3. Extends from the photic zone into the aphotic zone
What is the Abyssal zone?
4000m–6000m
2. ~42% of ocean floor
3. Totally aphotic
What is the Hadal zone?
6000 m up to ~11000 m
2. Pressures up to 1100 atm
What is the midwater?
a catch-all phrase referring to the water column (and the
organisms who live there) below the surface but above the bottom
What is the mesopelagic midwater?
the midwater between 200 and ~ 1000 m.
What is the bathypelagic midwater?
the midwater from ~ 1000 m - ~ 4000 m (i.e., to the bottom for much of the ocean).
What is the OMZ?
Oxygen Minimum zone, Caused by marine snow raining down, with bacterial
decomposition consuming oxygen
