Marine Flashcards
Five Oceans of the World
Atlantic Ocean Pacific Ocean Indian Ocean Arctic Ocean Antarctic (or Southern) Ocean
Australia is surrounded by 3 oceans
Pacific Ocean
Indian Ocean
Antarctic (or Southern) Ocean
Chemical & Physical Properties of water
- Polarity
- Cohesion
- Adhesion
- High heat capacity
- Universal solvent
- salinity
- Density
- Temperature
- Light penetration
Polarity
Uneven distribution of charges across a molecule making one end positive (H) and the other negative (O)
Cohesion
• Hydrogen bonds hold water molecules together. Cohesion creates surface tension
Adhesion
The tendency of water to stick to other substances
High heat capacity
- Water has the highest specific heat capacity of any liquid. Specific heat is defined as the amount of heat one gram of a substance must absorb or lose to change its temperature by one degree Celsius. For water, this amount is one calorie, or 4.184 Joules.
- Because water absorbs and releases heat at a rate much slower than land, air temperatures in areas near large bodies of water tend to have smaller fluctuations
Universal solvent
• Water can dissolve many substances
-able to separate ionic bond from substances
Dissolved salt (salinity)
• Seawater is 3.2% to 3.7% salt (~35 ppt – parts per thousand or PSU = Practical Salinity Unit)
• 99.6% comprised of: chlorine (Cl), sodium (Na), and magnesium (Mg), sulpher (SO4), calcium (Ca), & potassium (K)
-salt of the water comes from eroding land, reaction from seafloor, volcanic activity, atmospheric depravity
- higher salt concentration occurs at tropical area due to high evaporation and low presentation and vice versa also in land lock and arid region
-melting of ice and connecting to river can also lower salinity
Properties of seawater
• Salt decreases heat capacity (~4%)
• Lowers freezing point (-1.9°C)
• Increases density
Density is a measure of how much mass there is in a given volume or amount of space. The density of any substance is calculated by dividing the mass of the matter by the volume of the matter
-The density of seawater is a function of temperature, salinity, and atmospheric pressure
Temperature
- lower temperature are found in the north poles near antartica.
- high temp are found in the equator
- the cause is due to more sunshine on the equator. the sunlight concentration is less in the poles area
- In australis, the temperature of the north coast is higher than that of the south coast
Light penetration
- Sunlight entering the water may travel about 1,000 meters into the ocean under the right conditions, but there is rarely any significant light beyond 200 meters
- Light with longer wavelengths is absorbed more quickly than that with shorter wavelengths
- The higher energy light with short wavelengths, such as blue, is able to penetrate more deeply
Ocean Currents
Throughout the ocean there is one interconnected circulation system powered by wind, tides, the force of the Earth’s rotation, the sun, and water density differences
Convection cells in the ocean
Cold, dense polar water is drawn down from higher latitudes and sinks to the ocean bottom, pulled down toward the equator as lighter, warmer water rises to the ocean’s surface.
Coriolis effect
The Coriolis effect describes the pattern of deflection taken by objects not firmly connected to the ground as they travel long distances around the Earth
-This is due to the earth revolve faster in the equator area than the pole
Rotating Earth
• North hemisphere deflect to right (clockwise)
• South hemisphere deflect to left (anti-clockwise)
Air movement
- air can also affect the surface water movement as they pull water along
- three cell patterns exist in northern and southern hemispheres due to unequal distribution of land and earths movement
- largest are Hardly cell: at the equator, warmer and less dense air rises up to 18 km and spread out underneath the tropopause while cool air sink down toward the poles end
- smallest are polar cells which acts in a similar way to hardy cells
- in the middle cell are ferral cell, not driven by temperature and flow in the opposite direction compare to the other two. transport heat from the equator to the poles and create area of semi permanent high and low pressure
Major ocean currents
- In the northern hemisphere, predictable wind know as trade wind blow from east to west and pull water with them, create surface current. due to clorioslus effect, it pull current to the right heading north. at 30 nrth lat, another wind cause the current to east , creating a close clockwise loop which is know as a gyre
- the same occur in the souther hemisphere but counter clock wise
Australia’s ocean currents
-Australia’s ocean currents influence pattern of rainfall on land, distribution of marine organisms and productivity of the sea
knowledge of currents useful when designing infrastructure, searcher and rescue
Upwelling
-wind flow parallel to the coast with coast line to the right. this cause water to move offshore allowing colder and nutrient-rich water to rise
most important is bonny upwelling, occur summer to autumn, oct to may
Tides
Tides are the periodic rise and fall of surface water caused by the gravitational force of the moon and the sun and by the rotation of the earth
Biological Oceanography
Biological oceanography is a field of study that seeks to understand what controls the distribution and abundance of different types of marine life, and how living organisms influence and interact with processes in the oceans
Primary Productivity
Marine primary producers use dissolved carbon dioxide, with sunlight and water, to make carbohydrates (~60 gigatons [109] of carbon are fixed each year)
Phytoplankton are free-floating prokaryotic and eukaryotic photosynthetic microbes that live in large bodies of water; they are very abundant (≥103 ml-1) and perform essential ecosystem services to sustain life on Earth
Phytoplankton are highly diverse (morphology, size, taxonomy), occupying different habitats in the global ocean (also exist in freshwater and estuaries)
Primary consumers
Zooplankton
• Copepods: about 7500 species, extremely abundant. Biomass ~0.8 and 2.0 billion tons
• Krill: Shrimp, etc., ~500 million tons in the southern ocean
• Meroplankton: Larval forms of barnacles, molluscs, fish, and jellyfish, all of which grow to be much larger animals
Secondary & tertiary consumers
- Planktivorous fish (sardines, anchovies)
- Baleen Whales
- Cephalopods
- Predatory fish
Higher-level consumers
- Large predatory fish
- Marine mammals
- Birds
- People
What is biodiversity
variety of life in the sea that comprise of variation in level of complexity from within species to across ecosystem
Four components of biodiversity
o Compositional diversity = the number of entities
o Structural diversity = the distribution of abundances of these entities in communities (α-diversity), can take into account relative abundance and evenness (=the extent to which species are equal in number)
o Divergence or disparity = the degree to which the entities differ (β-diversity)
o Functional roles these entities play in ecosystems = e.g., trophic, metabolic, habitat forming
Most commonly used measures of biodiversity
- Genetic diversity
- Species diversity
- Community/Ecosystem diversity
Genetic diversity
Diversity within species: variation within the genome of a species
Contributes to adaptive potential
New genetic variation arises via
o Mutation
o Interbreeding (recombination)
o Migration of individuals
Forces operating on standing genetic variation
o Genetic drift (chance)
o Environmental drivers & natural selection - adaptation
Species diversity
-the abundance and variation of species living in a specific area
• Only ~226,000 multicellular eukaryotic marine species of an estimated total of ~2.2 million have been described (Appletans et al 2012; Mora et al 2011)
• This is 1/5-1/4 of all eukaryotic species on Earth
• Molecular methods will add/are adding tens of thousands of (cryptic) species
Indo-Pacific – Australia is a biodiversity hotspot
Australia is home to ~11% of known multicellular eukaryotic marine species
- 50 thousand marine species (32000 describe)
- 5k fish
- 30% of shark and ray
Community/Ecosystem diversity
-The variety of different habitats, communities and ecological processes
-Six discrete marine regions have been identified under Australia’s marine bioregional
planning in support of the Environment Protection and Biodiversity Conservation Act
-A marine bioregional plan has been developed for each region that describes its marine environment and conservation values, sets out broad biodiversity objectives, identifies regional priorities and outlines strategies and actions to address these priorities.
-North, Coral Sea, Temperate East, South-east, South-west and North-west
