Classification of Marine Organisms Unit 2 Flashcards
What are the three types of marine organisms?
nekton, plakton, and bethos
Plankton nickname, definition, 3 examples
“drifters”
Small microscopic organisms that drift or float in the water.
Jellyfish, diatoms and protozoans
Nekton nickname, definition, 3 examples
“swimmers”
Aquatic animals that swim and move independently in water currents
Fish, squid, octopus
Benthos nickname, definition, 3 examples
“Bottom-dwellers”
Flora and fauna found at the bottom of oceans, lakes or seas. They can also be found in sediments
Sea anemones, sponges, coral
Phytoplankton (D & E)
autotrophs (undergo photosynthesis) diatoms and cyanobacteria
Zooplankton (D and E)
heterotrophs. Krill and isopods
Bacterioplankton (including picoplankton) (D and E)
Free living bacteria. Purple and green bacteria.
Virioplankton (D and E)
Even smaller than bacterioplankton. Bacteriophages and algal viruses
Holoplankton (D and E)
Organisms that spend their entire lives as plankton. Krill, diatoms
Meroplankton (D and E)
spend their adult life as nekton or benthos but as a juvenile are plankton. Crabs, octopus.
Macroplankton (D and E)
Large floating animals/algae. Jellies and sargassum
Why aren’t nekton able to move throughout the entire ocean?
Gradual changes in temperature, viscosity and availability of nutrients limit their lateral range. Changes in water pressure limit their vertical range.
3 types of benthos
epifauna, infauna, nekton benthos
Epifauna (D and E)
Live on the surface of the sea floor, either attached to rocks or moving along the bottom. Crustaceans.
Infauna (D and E)
live buried in the sand, in discarded shells, or within the mud that exists on the sea bottom. Clams
Nekton Benthos (D and E)
Live on the bottom of the ocean yet have the ability to swim/crawl through the water above the ocean floor. Octopi, crabs.
What percent of marine organisms are terrestrial? What percent are marine?
87% of species are terrestrial, 13% are marine.
How many marine and terrestrial species inhabit Earth?
The total number of species cataloged in both marine and terrestrial biomes is 1.8 million.
How many species are discovered each year?
2,000 species are discovered each year.
Why don’t we know more about the ocean?!
Because of the ocean’s immense size and its inaccessibility
If the ocean is such a prime habitat for life and if life originated there, why do so few of the world’s organisms live in the oceans? (3 reasons)
The marine environment is more stable than the terrestrial, especially in temperature, meaning that it lacks variability so less species evolve from the environment.
What are the 2 major divisions in the oceans?
Pelagic and benthic
Name the 2 zones that the pelagic environment is divided into
Neritic province and oceanic province
Pelagic definition
Where drifters and swimmers live
Benthic definition
Where marine algae and animals that do not float or swim live
Neritic province
Extends from the shore seaward and includes all water less than 660 ft deep, typically the continental shelf.
Oceanic province
seaward of the neritic province, depth beyond 660 ft, continental slope.
The oceanic province is subdivided into four zones. Name each and give a brief description of each. Know depth (in meters) of each zone.
Epipelagic: Surface -> 200 m. Oxygen levels decrease, nutrients increase
Mesopelagic: 200 -> 1000 m. Bioluminescence is common. Shrimp, squid, deep sea fish
Bathypelagic: 1000 -> 4000 m.
Abyssopelagic: deepest parts of the ocean below 4000 m.
2 zones within the benthic environment
Subneritic and suboceanic
Subneritic province
from the spray zone to a depth of 200 m, with the continental shelf
Suboceanic province
includes the benthic environment below 200 m, ocean is covered by oceanic sediment. Tracks and burrows of animals live in the sediment.
How many known marine species exist?
228,445 species exist
What % of marine species inhabit the pelagic environment? Why?
Only 2% inhabit the pelagic environment. This is because the ocean floor has many different environments (rocky, muddy, flat, sloped etc) to which speciation has occurred.
Pelagic traits
lighter and warmer, the open sea, depends on sunlight and plants, is not more than atmospheric pressure and has mainly plants, herbivores and carnivores.
Benthic traits
darker and cooler, the bottom of the ocean depends on the decaying matter, an area of immense pressure, mainly scavengers and detritivores.
Euphotic (D and D)
supports high levels of photosynthesis (surface to 200 m)
Disphotic (D and D)
no photosynthesis (200 m to 1000 m)
Aphotic (D and D)
no photosynthesis but bioluminescence (1000 m to 6000 m)
El Nino (trade winds, temp, jet stream)
Trade winds weaken, Pacific is warmer than usual, jet stream southward
El Nina (trade winds, temp, jet stream)
Trade winds strengthen, Pacific is colder than usual, jet stream northward
How long do El Nino and El Nina last?
El Nino lasts around a year where La Nina lasts between one and three years.
Need for physical support
water physically supports marine flora and fauna. Phytoplankton depend on buoyancy and frictional resistance to sink in order to remain in their desired position
Viscosity
A substance’s internal resistance flows and is strongly influenced by temperature. As water temperature increases, water viscosity decreases. Animals have adapted their bodies to be more aerodynamic (streamlining)
Temperature
Ocean temperatures have a narrower range than temperatures on and, this is because there is a higher heat capacity in water and the warming of the ocean is reduced thanks to evaporation.
Salinity
The salinity of the water relates to its salt content. Some organisms are stenohaline while others are euryhaline depending on their tolerance of salinity.
Dissolved gasses
cold water dissolves more gas than warm water. Gill structure will vary in different organisms to compensate.
Transparency
Water has a relatively high transparency, it can be used for camouflage, migration, disruptive coloration etc by organisms.
Pressure
water pressure increases the deeper down in the ocean you go. Most marine organisms cannot travel down that far as a result, as they need to have specialized lungs, ear canals, and other passageways to cope with the extreme pressure. Fish have swim bladders that allow them to adjust their buoyancy.
Stenothermal
organisms that can tolerate a small temperature range
Eurythermal
organisms that can tolerate a wide temperature range
Stenohaline
organisms that can tolerate a small salinity range
Euryhaline
organisms that can tolerate a wide salinity range
Camouflage
an example of this is a rockfish, they are covered in patterns that help them blend in.
Countershading
organisms that are dark colored on top and light on the bottom so that predators have a hard time spotting them from above or below. Halibut are an example.
Daily vertical migration
Organisms go deeper down into the water during the day to avoid predators and come to the surface at night.
Disruptive coloration
Large, bold patterns to advertise their identities, attract mates or to display weaponry such as spins or poison to ward off predators.
Hypotonic
SW
Hypertonic
FW
low osmotic pressure
SW
High osmotic pressure
FW
drinks water
SW
doesn’t drink water
FW
absorbs salts
SW
excretes salts
FW
Excretes large volumes of water
FW
Excretes small volumes of water
SW
urine is dilute
FW
urine is concentrated
SW
El Nino effect on US
Northern US is dryer and warmer, gulf coast and southeast are wetter and have increased risk of flooding
La Nina effect on US
drought in the southern US, heavy rains and flooding in the Pacific Northwest. Winter temperatures are warmer than normal in the south and cooler than normal in the north. Causes hurricanes.
