The Marine Environment 1
The Marine Environment
How physical and chemical properties of water affect life
in the sea
The Marine Environment 2
Salinity Seawater
contains a variety of dissolved solids
Open ocean salinity can range from 34 - 37 parts per thousand
Salinity is measured: Conductivity of Cl-
Refractometer
The Marine Environment 3
How salinity affects marine organisms
Most marine animals are adapted to a narrow salinity range Changes is salinity effect organisms through osmosis
Hyperosmotic solution- water will flow into it across a semipermeable membrane
Hypoosmotic solution - water will leave the solution
The Marine Environment 4
How to Cope Osmoconformers
Allows its internal salt concentration to change with the salinity of the surrounding water
Some molluscs & polychaete worms
Osmoregulators Keeps its internal salt concentration
constant regardless of the water salinity Many fishes & crabs
The Marine Environment 5
Temperature Regulation Homeotherms (Endothermic) - organisms which
regulate their internal body temperature regardless of the environment
Poikilotherms (Ectothermic) - organisms which have an internal body temperature that conforms to the environment
The Marine Environment 6
Temperature Stratification Thermocline is an area in
the water column of rapidly changing water temperature Thermoclines are most
prominent during the warmer months due to solar radiation and weak mixing
After the thermocline the water is an almost constant temperature
The Marine Environment 7
Methods for Measuring Temp.
Niskin Bottles
Satellite Imagery
The Marine Environment 8
Dissolved Gases Dissolved Gases
For living things the three most important dissolved gases are oxygen (O2), carbon dioxide (CO2) and nitrogen (N2)
The amount of a given gas that can dissolve decreases with an increase in temperature
The amount of oxygen in a body of water depends on: Mixing with the atmosphere Respiration Photosynthesis
Sunlight + 6H20 + 6CO2 C6H12O6 (Glucose) + 6O2
The Marine Environment 9
Oxygen Consumption Aerobic respiration
Respiration in the presence of oxygen Anaerobic respiration
Respiration in the absence of oxygen
The Marine Environment 10
Light Light is crucial for
photosynthesis and is strongest in the surface waters
Light attenuates with depth in an exponential fashion
UV light can be damaging to the proteins and DNA of many surface organisms
Effective light penetration can vary from 10-1,000m.)
The Marine Environment 11
Turbidity and Light Penetration Turbidity
The amount of solid particles suspended in the water column
Important since plants and algae need light for photosynthesis
Increase turbidity can decrease the amount of light which effectively penetrates
Large concentrations of phytoplankton can decrease light penetration (greenish tint)
The Marine Environment 12
Pressure Animals that live on land or
sea level are at 1 ATM (14.7 psi) With an increase in depth of
10 meters (33 ft) pressure is increased by 1 ATM.
Gas filled structures will shrink or collapse with depth
At the ocean’s avg. depth (3,700 meters) pressure is 2.7 tons per square inch
The Marine Environment 13
Properties of Water Water is more dense
and viscous than air Since it is a more
supportive medium there is not a need for a strong supportive skeleton
Also, an important consideration when we discuss sinking rates and movement through water
Surface tension
The Marine Environment 14
Ecological Principles
Interactions among animals and the environment
The Marine Environment 15
What is Ecology? A combination of biotic and abiotic factors
Biotic
Predator-prey interactions
Symbiotic relationships
Competition
Species interactions
Abiotic
Salinity
Temperature
Pressure
Non-biological factors
In the real world these factors are not easily separated
The Marine Environment 16
Ecological Principles Ecology: the
interactions of animals with each other
Habitat: the environment where an organism occurs Habitat can vary in
temperature, salinity, tides, and currents
The Marine Environment 17
Key Ecology Terms Species: natural group of interbreeding
individuals, which are reproductively isolated from other groups
Population: all the species in a given area Community: several populations, which
occur in an area Ecosystem: a series of communities and the
surrounding environment
The Marine Environment 18
Competition Competition:
refers to the interaction between organisms for a necessary and limiting resource Light, food, water,
and spaceBarnacle and mussels compete for space
The Marine Environment 19
The Results of Competition Natural selection: production of offspring by
the best-adapted individuals in a population Evolution: a change in the genetic makeup
of a population To be successful a species must find the
right balance between specialization and generalization Niche: the role a species plays in the community
The Marine Environment 20
Predation Predation is the
act of one animal eating another Coevolution - the
predator evolving in response to adaptations of the prey, or vice versa
The Marine Environment 21
Living Together Symbiosis
Commensalism
Mutualism
Parasitism Ectoparasites Endoparasites
The Marine Environment 22
Ocean Ecosystem Components
Autotrophic: organisms which capture energy to make organic matter Producers
Heterotrophic: organisms that capture energy by eating Herbivores - eat strictly producers Carnivores or piscivores - eat meat or fish Omnivores - generalists Apex predators - top predators
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