Flashcards in L11 + L12 Deck (101):
what is the pelagic province
the water column
what is the neritic zone
the shallow water that overlies the continental shelf
what is the oceanic zone
the deep water in the open sea beyond the shelf break
what are the 5 distinct horizontal zones of the water coumn
what depth is the epipelagic zone and what is its features
200m mostly illuminated ( not so much at depth)
what depth is the mesopelagic zone and what is its features
200 - 1000 m hardly a trace of sunlight
what depth is the bathypelagic zone
1000 - 2000 m
what depth is the abyssalpelagic zone
2000 - 6000m
what depth is the hadalpelagic zone
anything deeper than 6000m (mostly found in deepsea trenches)
what is the sublitoral zone
the floor of the continental shelf and extends from the beach to the shelf break
what is the intertidal zone ( littoral)
the part of the shoreline between high and low tide
what is the bathyal zone
the sea bottom that extends to a water depth of 2000 there fore encompasses the mesopelagic and bathypelagic zone
what are the abysal and haydal zones
the deepest sea bottom found beneath the abbysalpelagic and hadalpelagic zone
what is the photic zone
the well lit part of the ocean, so that photosynthesis can occur during the day time
how deep is the photic zone
water surface to 20/100m depending on water clarity
what is the dysphotic zone
the twilight zone - low levels of illumination - no photosynthesis
what is the aphotic zone
part of the ocean that is in total darkness
what are the 3 domains that biologists seperate all living organisms into
what is the other name for those grouped in archaea
what are eukaryota
complex organisms with a cell nucleus
what does kingdom monera include
bacteria and simple microscopic one celled organisms with no nucleus
what are three reasons bacteria are important
-conduct significant amount of photosynthesis
- covert ammonia and nitrogen to nitrite and nitrate
- dominate environments that are too stressful for most organisms
what organisms fit into kindgdom protista
single celled organisms that possess a single true nucleus
what do protista do
take up and release chemicals in seawater and serve as food for larger organisms, also contribute to the pelagic sedimentary deposits in the ocean
what are metaphytae
marine plants eg phytoplankton
what does kingdom protista consist of
a. This kingdom includes plants and animals such as foraminifera, coccoliths, diatoms, and radiolaria.
b. The shells from these groups constitute most of the deep-sea oozes.
what does kingdom chromista consist of
metaphytae . This kingdom includes the red, brown, and green algae, as well as the advanced plants of the salt marshes and coastal swamps.
b. Plants attached to the seafloor are only found in shallow areas of the shoreline and the inner continental shelf.
c. Floating plants are mainly microscopic in size and include diatoms and dinoflagellates.
what does kingdom chromista consist of
marine plants (metaphytae) some free floating and others attached to the sea floor
what does kingdom fungi consist of
where is fungi most common
what is metazoa
what is plankton and what groups are they seperated into
organisms that drift or swim weekly phytoplankton and zoo plankton
what are nekton
active swimmers such as fish or squid
what are benthos
organisms that are attached to or move on or beneath the sea bottom
where do benthic bacteria and animals live
all depths on the ocean floor
what are the benthos further divisions ( name and what they are )
epifauna and epiflora - animals and plants that live on the ocean bottom
infauna - animals that live in the sea bottom
briefly describe how plankton are sampled
plankton nets are towed behind ships, the size of the mesh openings depend on what kind of plankton they are trying to catch, by monitoring the amount of water has passed through the net they can investigate the plankton concentrations
different method - draws water through a hose and passes through a filter system consisting of a series of nets, different sizes of plankton can be separated and counted
briefly describe how nekton organisms are sampled
typically large coarse net towed behind the ship to catch large swimmers
how are benthic organisms sampled
using and anchor dredge or grab sampler
the totality of an environment, which includes all of its living and non living parts
what are the two different catagories of organisms that live on the sea bed
- epifauna: live on the bottom
- infauna: live in the sediment
What sections can the substrate be divided into and what is the difference? (2)
-shelf: shallow and near a terrigenous source
-deep ocean basin: deep and far from terrigenous sources
what kind of grain size is deposited in high and low energy environments
- high energy condiotons allow deposition of only the larger grains due to the smaller grains being held in suspension
-low energy conditions allow deposition of smaller particles: larger particles are rare because there isnt enough energy to transport them there
what two areas can the sea floor be divided into based off energy?
- high energy environments -typically near the shore and in shallower water
-low energy environments - which occur below the wave base in shallow areas
how does bottom energy effect organisms and why does this make it difficult for epifauna to live there?
moving sediment around and creating an unstable substrate this makes it difficult for epifauna to become established
how do strong currents control sediment grain size
-Strong currents can sweep away all sediment and leave rock exposed.
-Mud collects in placid environments such as below wave base and in protected nearshore areas.
-Sand and gravel collect in high-energy areas, especially the inner and middle shelf where it is too turbulent for mud to be deposited
how does bottom sediment influence the feeding mode of benthic communities
- Substrates of gravel and coarser sediment are mainly inhabited by filter feeders, because the grain size is too large to ingest and the turbulent water that prevents deposition of finer sediment would also keep most food in suspension.
- Substrates with fine sand and coarse silt have a mixed fauna of detritus deposit feeders, infaunal filter feeders, and a few epifaunal filter feeders.
-Muddy substrates are populated almost exclusively by deposit and detritus feeders because the sediment is rich in organics and the low energy conditions keep little material in suspension.
what are the two major benthin comunities based on substrate
a. Hard-bottom communities—found in most high-energy, intertidal environments and characterized by a substrate of rock or gravel. Seaweed and a diverse benthic fauna are typically found in such communities.
b. Soft-bottom communities—substrate composed of unconsolidated sand and mud with a fauna largely controlled by grain size with one group typically dominating. In clean sands, filter-feeding bivalves dominate, but their numbers decrease as the mud content of the sands increases and are replaced by worms and snails.
what type of zonation do benthic communities display
the zonation is verticle and parallels the sea level, it often reflects the time the area is submurged and the ability fo the organism to survive the stress of exposure
describe the upper, next lower and lower zonation of intertidal benthic comunities
The uppermost level is rarely wet and is inhabited mainly by blue-green algae and snails.
b. The next lower level is occupied by barnacles near the top and mussels and brown algae at the base. The size of barnacles tends to increase downward because those living lower in the zone are submerged more often, for longer periods of time, and so they can feed more frequently.
c. The lowest zone has diverse fauna and flora.
How do benthic communities respond to substrate
A rocky substrate provides a stable and firm material for attachment but prevents burrowing.
b. A sandy substrate is mobile and abrasive, but animals can burrow into it.
c. A muddy substrate provides little support but is easy to burrow through.
The benthic food chains largely depend on food from the surface that reaches the bottom, list these 3 types
a. Fine to coarse detritus that settles slowly through the water.
b. Large carcasses.
c. Organic detritus swept onto the deep-sea bed by turbidity currents.
what link does amount of biomass and depth
amount of biomass decreases with depth - this is more important than distance from shore because it affects how much food is available to them
Characteristics of the benthic organisms include:
a. Year-round reproduction.
b. Small broods.
c. Slow growth.
d. Long life.
Four traits common to all abyssal depths are:
a. Perpetual darkness.
b. Low temperature.
c. High hydrostatic pressure.
d. Sparse food supply
why is the diversity of the benthos greater than we would expect
because the high predation rate prevents any group from dominating through competitive exclusion (when one group outcompetes most others and drives them to extinction).
how does the rate of bacterial decay change with hydrostatic pressure and how does this effect organic material on the sea bed
it is greatly reduced therefore organic matter that has settled on the seabed persists for a long time before it decays and is more likely to be consumed by scavengers.
what forms around volcanic/ hydrothermal vents
deep sea communities of abundant and diverse fauna
give an example of a volcanic/hydrothrmal vent
describe how minerals form chimneys on mid ocean ridges
Water heated by magma flows through a fracture and leeches metals from the basalts. As the water cools, precipitates of sulfide and sulfate minerals form chimneys.
describe chemosynthesis and what depends on it
Bacteria from the vents perform chemosynthesis, oxidizing hydrogen sulfide and using the energy released to synthesize food in the absence of light.
Filter-feeding invertebrates around the vent depend on chemosynthetic bacteria for food
what are the 5 groupings of botany and zoology
The categories from the largest grouping to the smallest are: Kingdom, Phylum, Class, Order, Family, Genus, and Species
in what year and who created the taxonomic classifications of botany and zoology
what are blue green algae
b. Blue-green algae are single-cell organisms that lack a nucleus and are important for converting ammonia and nitrogen to nitrates and nitrites.
what can temperature control in relation to organisms
Temperature can control distribution, degree of activity, and reproduction of an organism.
how does the temperature of the water and the chemical reactions of an organism relate
b. For every 10oC rise in temperature, activity rates double. In polar waters, animals grow more slowly, reproduce less frequently, and live longer than do the same organisms in the tropics.
how can temperature indirectly control organisms
d. Temperature can indirectly control organisms by limiting (or encouraging) their predators or restricting (or enhancing) pathogens.
can a organisms tolerance to temperature vary?
Yes, tolerance to variation in temperature varies greatly between species and during an organism’s life span.
how can salinity control the distribution of organisms
Salinity can control the distribution of organisms and force them to migrate in response to changes in salinity.
which kind of organisms ted to be more tolerant to changes in salinity
Epipelagic organisms tend to be more tolerant of changes in salinity because their environment is more subject to changes than in the deeper ocean.
how does the chemical composition of seawater affect a organisms capability to survive
Availability (or lack) of various dissolved chemicals can limit an organism’s ability to construct shells.
e. Osmosis is the movement of water molecules through the cell membrane from where salinity is lower to where it is higher.
Osmoregulation is the control of diffusion through the cell wall and the maintenance of sufficient body fluids.
Some marine organisms drink large amounts of water and have chloride cells that extract and dispose of excess salts, leaving the body with a ready supply of water to replace that lost by diffusion. This keeps cellular salt concentrations low in the presence of high-salinity ocean water.
Freshwater organisms tend not to drink and have kidneys that produce large amounts of very dilute urine to dispose of excess water gained by diffusion. This keeps cellular salt concentrations higher in the presence of low-salinity freshwater.
how can osmosis cause dehydration
Osmosis can result in the dehydration of the cell if the surrounding water is more saline or in the rupturing of the cell if it is more saline than the surrounding water.
what is hydrostatic pressure
Hydrostatic pressure is the pressure exerted by a column of water surrounding an organism.
how is the amount of hydrostatic pressure on an organism determined
a. The amount of hydrostatic pressure is determined by the height of the water column and the water’s density, which is a function of the temperature, salinity, and turbidity.
how do deep ocean fishes overcome the issues of hydrostatic pressure at depth (stop themselves exploding)
don't have an air bladder
what is the only sea weed in the open ocean
what are the three major phytoplankton
diatoms, dinoflagellates, and coccolithophores
what are the two major zoo plankton
foraminifera and radiolaria
which phytoplankton is dominant at the shallow coast but decrease in abundance seaward
how do plants stop themselves sinking and then leaving the photic zone (4)
b. Increasing surface area slows sinking because of the frictional drag between the surface and water.
c. Because volume increases faster than surface area, small size produces a slower settling velocity because of a lower mass and greater frictional drag.
d. Plants also decrease mass by having porous shells, and they increase frictional drag by developing spines that increase the surface area relative to their volume.
eLarge plants anchor themselves in place with holdfasts, rootlike masses that function only to hold the plant in place, not to absorb nutrients and water from the sediment as do roots.
what are diatoms, what are they made from and what is there shape
Diatoms are single cells enclosed in a siliceous (made from silica, or SiO2) frustrule (shell) shaped like a pillbox.
how do diatoms reproduce
In reproducing, the frustule separates into the larger epitheca and smaller hypotheca.
b. Each part then secretes a new hypotheca. The original hypotheca now functions as an epitheca.
c. After numerous generations, one of the cell lines becomes progressively smaller until it reaches a critical size, abandons the hypotheca, reproduces sexually, grows larger as a naked cell, and finally develops a frustule of the side of the original one in the sequence.
what kind of conditions do diatoms thrive in
Diatoms thrive in the cold, nutrient-rich waters of the polar and subpolar regions and in the inshore water of the shelf in the midlatitudes.
e. They can reproduce rapidly and produce plankton blooms in ideal conditions.
what are dinoflagellates
Dinoflagellates are single cells with two whiplike tails (flagella).
what are dinoflagellates shells called and composed of
Their shell, called a theca, if present, is composed of cellulose.
what can happen to dioflagellates when concentrations of dissolved silica is low
When the concentration of dissolved silica is low, dinoflagellates can outnumber the diatoms.
what are copepods
Copepods are small herbivores (plant-eating organisms) that filter diatoms from the water.
what are forminifera
Foraminifera are single-celled, microscopic organisms that build shells of calcium carbonate.
which form of formanifera outnumbers the other? Bentheic or pelagic
how do forminifera eat food
b. Their shells are porous, and protoplasm streams from inside the shell to engulf and digest food.
what happens to copepods shell as they grow
they molt their outer skeleton
do copepods migrate?
yes vertical seasonal migration
what kind of fauna is found in the disphotic zone
prawns, shrimp, copepods, amphipods, ostracods, squid, and fish.
fish in the dispotic zone have special adaptations such as (3)
1. large, light-sensitive eyes.2. photophores (light-generating structures) that produce bioluminescence. Light is generated by bacteria in the photophores and is used for species identification and for attracting prey.
c. Food in the dysphotic zone is scarce, so some organisms display diurnal vertical migration, whereby they migrate to the surface at night to feed and during daylight descend to depths of 700 to 900 meters.
what are 4 common traites in the abyssal depths
b. Low temperature.
c. High hydrostatic pressure.
d. Sparse food supply
give examples of dwellers in the aphotic zone
b. The major dwellers in these dark depths include copepods, ostracods, jellyfish, prawns, mysids, amphipods, and a variety of worms and fishes.
list some characteristics of mid water fish
. Low abundance.
2. Small size, about 2 to 10 cm.
3. Large mouth with many sharp-pointed teeth.
4. A jaw that can be unhinged to accommodate large food.
5. An expandable stomach.
6. Bioluminescence to attract prey.
7. In some forms, the male is parasitic upon the female.
what are copepods and forminifera examples of