Test 1 Flashcards
Why study marine biology?
It is the study of plants, animals, and other organisms that live in the ocean. Marine life represents an enormous source of human wealth such as food, medicine, raw materials (algae) and recreation.
How can marine organisms create problems for humans?
Shellfish poisoning; ciguatera poisoning; shark attacks; erosion of structures we build (piers, sea walls), fouling of ship bottoms
Fundamentals of Marine Bio
Marine life helps determine the very nature of our planet
Marine organisms produce much of the oxygen we breathe (helps the earth’s climate)
Shorelines are shaped and protected by marine life
- Calcium carbonate sand deposition
- kelp beds
How long ago did life appear in the ocean?
3.8 billion years ago
Animal and plant life?
Extant today, had ancestors that evolved 500 million yrs ago
How old is earth?
4.7 billion years old
Continental Drift
Supercontinent = Pangea: suggests that all the continents had once been joined
- Glomar Challenger 1960’s
- sediment cores (more sediment further away from ridges)
- magnetic signature of crust
Plate Tectonics
Sea floor spreading?
Deep sea vents
Earth’s crust divided into a number of irregular plates;
2-16 cm/yr
Thermophilic and chemotrophic bacteria
Currents
The major wind fields of the atmosphere push the sea surface creating currents
The marine environment is divided into zones according to (3 things)
distance from land; water depth; and whether the organisms are benthic or pelagic
Neritic
pelagic environment that lies over the shelf (also called the coastal zone)
Oceanic zone
Pelagic waters beyond (seaward) the shelf break
Epipelagic
shallowest zone, plenty of light for PS
Mesopelagic
not enough light for PS
Bathypelagic
no light
abyssopelagic;
hadopelagic
flat abyssal plain; trenches
Benthic
live on (epifauna) or buried in (infauna) the bottom some are sessile (attached) some move around (mobile)
Pelagic
up in the water column
away from the bottom
Plankton move at the _
mercy of the currents
Phytoplankton
planktonic plants and other autotrophs are carried from place to place
zooplankton
animal plankton
Nekton
animals that can swim out of currents such as fish, marine mammals, squids, and large jellyfish
Water accounts for _% of the volume of most marine organisms;
Water provides _ and _ _ for
80-90;
buoyancy and body support for swimming and floating; reduced need for heavy skeletal structures
Properties of seawater
Water is a universal solvent
High heat capacity (slow change in temp)
Density temperature relationships (>4oC density increases with decreasing temperature)
<4oC density temperature pattern reverses
Increased viscosity (affects sinking)
Properties of seawater part 2
Heat capacity: In the sea heat is transferred from place to place by
convection (mixing)
subtle conduction (molecular exchange of heat, ie., photons impart energy to water molecules)
Light
Used by marine organisms for vision and PS (euphotic zone)
The _ of the _ _ is determined by how rapidly seawater _ _ and _ it to _ _.
depth; photic zone; absorbs light; converts; heat energy
Factors that diminish quantity/intensity of light available for PS activity include:
suspended sediments concentrated plankton populations clouds, dust, fog angle of incident light/reflection dissolved substances season, time of day, latitude
Temperature
High heat capacity: limits marine temperatures to a much narrower range than land temperatures.
Density _ as temperature _ or salinity _.
increases; decreases; increases
Why is most dense water found at the greatest depths?
Evaporation, cooling, freezing; dense water sinks from the surface
This sinking drives the circulation of water in the deep portions of ocean basins
Pressure
Land organisms are exposed to 1 atmosphere
With each 10m (33 ft) of depth _
1 atmosphere is added
The three most important gases for life in the ocean are
o2, co2, and N
They dissolve in seawater at the sea surface;
Gases dissolve better in cold water;
most solids dissolve better in warm water
Oxygen is added to near surface, seawater by
PS activity
Oxygen is consumed by
Respiration throughout the water column
_ + _ use oxygen as fast as it can be replaced in the oxygen minimum zone (200 - 1K meters)
animal respiration; bacterial decomposition
Adaptations of oxygen minimum zone
larger than usual gills, inactive, hemoglobin adapted to low oxygen concentration
Oxygen to deeper water
Dense water sinks
Sinking surface water carries oxygen to the deep sea bottom
Circulation caused by changes in water density (usually at poles) is called
thermohaline circulation
Cooling, freezing, and salt concentration cause surface seawater to sink as _ increases; How?
density increases;
- cooling by contact with cold air
- formation of sea ice
- evaporation leaves behind salts
Ways to decrease seawater density:
warm it or dilute it with freshwater
Shortages of _ and _ usually limits the overall _ of life in the sea, in fresh water and on land
P and N
Phosphate ion is used to link larger molecules such as
nucleotides, DNA, RNA, ATP
How is phosphorous distributed within the water column?
liberated from cells they smash
voiding partially digested feces
simple leakage through body surfaces
Bacterial decomposition: liberates PO4 and other nutrient atoms)
Liberation of any nutrient atom back to the water= regeneration or remineralization
Phosphorous _ _ benefits the plants that have escaped being eaten.
Remineralization immediately
When organisms _ and _: the _ they contain is _ in __
die and sink; phosphate; remineralized in deep water
Nitrogen is a component of _, _, DNA, RNA, and many other biological molecules.
proteins, chlorophyll
Sources of nitrogen
Nitrogen-fixing bacteria
Nitrate bacteria
Excretion of nitrogenous wastes (usually ammonium) in urine
Urea or uric acid
Plants take up _, _, and _. Plant and animal _ releases _ and organic _.
Nitrate, nitrate, and ammonium.
decomposition; ammonium, nitrogen
Phytoplankton characteristics (3):
free-floating
flagella, to swim short distances
Most are denser than water
_ and _ availability are the major factors that determine new cell production
Population growth =
Light and Nutrient;
rate of new cell production - rate of cell loss
Two ways cells are lost from populations:
Consumption by grazing animals
sinking (sedimentation)
Smaller cells have a greater _
surface-to-volume ratio
_ and other projections make the organism more difficult to eat.
Spines
Purpose of zigzag back-and-forth
Keeps seawater flowing over cells surface
Renews the layer of water
Facilitates gas exchange, nutrient uptake and waste disposal
Herbivore grazers
protozoa, rotifers, crustaceans, euphausiids, krill
Near shore, benthic, suspension-feeding animals
barnacles and mussels
Diatom characteristics
Siliceous wall called a frustule
surrounds their nonflagellated vegetative cells
Frustule has 2 valves
_ is the older and usually larger valve (hypovalve; hypotheca)
Two categories of diatoms
Centric and Pennate
Blooms occur when _
5 million cells/liter is reached. Algae color the water
Diatoms reproduce _ following mitosis
asexually
Explain diatom reproduction. When?
The hypovalve of the parent becomes the epivalve of the other smaller daughter
- In cells that are less than half the maximum size for the species.
- When harsh environmental conditions predominate (light, temp., low nutrients).
Two types of zooplankton
Holoplankton: spend their entire lives in plankton
Meroplankton: species that spend part of their life in the plankton;
- include large numbers of larvae of animals that live as adults on the bottom or swim as nekton
Flotation mechanisms of zooplankton:
exclude heavy ions, retain NH4Cl, or actively exclude SO4 and replace with chloride ions
Gas or fluid filled floats
CO2 bubbles
Flat or spines
Non-crustacean zooplankton
Transparent, planktonic larvaceans
Float inside a “house” made of mucus
Beat their tail
the larvacean pumps water in through passages in the house
food particles are caught in a complicated mucus net
that is secreted inside the house.
Characteristics of Jellyfish and siphonophores:
large but weak swimmers
drift with currents
eat small fish and zooplankton
(Ctenophores (comb jellies): zooplanktivorous)
Siphonophores: Cnidarian or coelenterate
A hydrozoan that forms drifting colonies.
Some polyps in a colony may be specialized as floats
(Portuguese man-of-war, Physalia physalis)
Winds and currents are strongly influenced by the _ _.
Coriolis effect.
Explain the Coriolis effect:
the earth is rotating from west toward east and anything moving over the surface tends to be bent toward one side rather than moving in a straight line
The effect pulls things to the _ in the N. hemisphere and the to _ in the S. hemisphere.
right; left
Wind that is generated in combination with Coriolis effect…
Moves surface water away from coastline, and deeper (<200m) water moves up to shallow water to replace surface water
Wind-driven surface current influenced by the _ _ combine into huge gyres (e.g, _ _)
Coriolis effect; Pacific Ocean gyre
What produces wind?
Differential heating of various regions of the earth’s atmosphere by the sun.
Waves are _ _ _ of the sea surface. The _ and _ of waves are dependent on the wind’s _ _ _. 3 things waves are characterized by:
Periodic vertical disturbances; size and energy; Velocity, fetch, duration; Height, wavelength, period
Seas
Wave crests w/sharp peaks with deep troughs
Explain what happens when waves enter shallow water
They begin to encounter frictional resistance of the bottom
slow forward motion
wavelength decreases
increase in height and become steeper
When water depth is less than 1/2 the wavelength, the wave breaks
releasing the energy onto the shore
Upwelling revisited
Equatorial upwelling
N. equatorial current (to right)
S. Equatorial current (to left)
Equatorial regions of the sea surface is being pulled apart, or diverging
Deep water moves up to fill the void
Nutrients support
phytoplankton, an array of copepods, anchovies, tunas, seabirds, other animals.
Where is the greatest sustained Upwelling on earth?
The Antarctic Divergence
65 S latitude
belt of upwelling that circles the S. Hemisphere
Tides
Only noticeable along ocean margins (coastlines), around islands.
Maximum elevation of the tide= high tide
Minimum elevation = low tide
Most coastlines experience two high and two low tides in a lunar day
=24 h and 50 min.
The vertical difference between consecutive high and low tides = tidal range
a few cm to 15 m in the narrow Bay of Fundy
Define tides:
Periodic changes in water level which result from the gravitational attractions of the sun and moon. (solar tide about 1/2 as large as the lunar tide).
Spring Tides:
Sun, moon and earth in alignment new and full moon solar tide has an additive effect on lunar tide creating extra-high tides and lowest low tides
Neap tides:
One week later
sun and moon at right angles to each other
solar tide partially cancels the lunar tide
Tides are affected by the _ and the _ of the _ _.
shape; sea floor
Tides vary from place to place depending on the (2)
location
the shape and depth of the basin
Semidiurnal tides? Where?
2 high tides and 2 low tides a day; east coast of N.America, most of Europe and Africa
Mixed semidiurnal tides? Where?
successive high tides of different height
most of the west coast of US and Canada
Diurnal tides? Where?
only one high and one low tide every day
Gulf of Mexico, on the coast of Antarctica, parts of the Caribbean and Pacific
Tide tables:
predicted time and height of high and low tides in a particular area
How can weather patterns influence tides?
Strong winds can pile up water on shore and cause higher tides than predicted
Three layered ocean
Stable water column: resists mixing
large density difference between deep and shallow water.
Thermocline: a zone of transition between warm surface water and the cold water below.
pycnocline parallels (mirror-image) thermocline
Surface temperature varies with _
Deep-water temperatures are more _
In temperate and polar waters _ _ may develop
latitude; uniform; summer thermoclines
El Nino
Refers to global change in atmospheric pressure that accompanies El Nino
- Normal years
High atmospheric pressure over the eastern Pacific
Low over the Indian Ocean
- El Nino years
Situation reverses
Atmospheric pressure shifts on a global scale.
ENSO
Pacific trade winds weaken/stops/ & may weakly reverse direction
S. Equatorial current slows/stops/reverses
Cold water along the S. American/N. American coasts allowed to warm up.
Warm equatorial water from the mid-Pacific backs up against the American coasts
spreads N & S
Warm water now affects upwelling
cold nutrient-rich water is abruptly replaced by warm nutrient-poor surface water.
La Nina
Unusually cold ocean temperatures in the Equatorial Pacific.
In the US, winter temperatures are warmer then normal in the Southeast,
and cooler than normal in the Northwest.
