Introduction to Marine Ecosystems

Ocean Ecosystem

• An ecosystem is a level of organization that includes living things and their environment

• Living things cannot exist without their environment

• Most of our planet is covered by the ocean or marine ecosystem

Structure and Function of an Ecosystem

What the ecosystem is made up of and how it works are linked and influence each other…

STRUCTURE

Amount of non living materials

How living conditions vary with time and space

Characteristics of living things

FUNCTION

Interactions between living things

Cycling

LAND vs OCEAN• Ocean is wetter than land

– Materials can be dissolved in ocean water– Gametes can be dispersed more easily– Harder for smaller things to move through water

• Ocean is more vast than land– Harder to find mates and food

• Ocean is more supportive than land– Body structure will be different than land animals

• Living in aquatic environment will shape biology and adaptations of marine life

ABIOTIC and BIOTIC FX

Physical or non-living parts of the environment that influence living things are called abiotic factors

examples:

Living factors which influence living things are called biotic factors

examples:

Abiotic Factors in the Ocean

• Inorganic nutrients like: C,N,H,P,S,Fe,Si

• Motion in the ocean: upwelling, currents, tides

• Dissolved materials like gases and salts

• Climate: temperature, light, pressure

• Variations in time and space

Inorganic Nutrients

• Most of the ocean is nutrient poor

• Only 10 percent of the surface area of the global ocean supports half the world’s fisheries

• Nitrogen, phosphorus, iron and silica are like fertilizer for ocean plants

Source of nutrients– Runoff from land, animal feces and

decomposition – all this material sinks out of reach

Surface nutrients get used up (by plants to make plant tissue) they become a limiting factor for the growth of new plants which are only found in surface waters

Nutrients are returned to surface waters by a special type of current called 'upwelling'

Other Ways Nutrients are Replaced

• Winter storms, after the thermocline has disappeared

• Deep water currents can be deflected by underwater island chains

Motion-Upwelling• Upwelling is a vertical current,

bringing nutrient rich water from the bottom to the surface.

• Upwelling areas support a lot of life• Occur off the west coasts of

continents or in the middle of the equatorial parts of oceans.

• Upwelling is often seasonal

www.coolclassroom.org/cool.../upwellingtutorial.html

Why Upwelling Happens

• Earth's rotation and strong seasonal winds push surface water away from coasts

• Deep water rises on the edges of continents to replace it.

uwgb.edu

Motion-Tides

• Alternating rise and fall of sea level– Produced by gravitational attraction to moon

and sun as well as the rotation of the Earth

• Tides produce strong currents up to 5 m/s

•

• http://www.oc.nps.edu/nom/day1/partc.html

Motion-Tides

• Area on the beach exposed between high and low tide is intertidal zone

• Organisms must deal with breaking waves, exposure above water, and daily variations in water temperature and salinity

• Adaptations, such as firm attachment to rocks and shells to hold in moisture, to deal with these conditions.

http://geosci.sfsu.edu/courses/geol102/ex9.html

Marine Life and Tides• Some marine life time their feeding

and reproduction to the high or low tide cycle

• Horseshoe crabs come ashore to mate on the night of a high tide in May

• Eggs hatch 2 wks later on a high tide and are washed into the ocean

Motion-Currents

Motion-Currents

• Ocean currents move heat around the globe and affect local climate

• Driven by atmospheric winds and Earth’s rotation

• Found in upper 400m and speeds around 1 m/s• Pollution, marine life and food can be stuck in

currents and moved around the globe

Dissolved Materials

• Seawater is fresh water plus dissolved materials like salts, minerals and gases

• Amount of material dissolved depends on temperature of water

Dissolved Gases

• Oxygen, carbon dioxide and nitrogen• Dissolve into the ocean from the

atmosphere through wave action also released at the surface back into atmosphere

• Dissolve better in cold water• Animal life and plant life can change

the chemistry of ocean gases

Dissolved Gases

• Plants photosynthesize, animals respire, bacteria decompose

• Plants use CO2 and produce O2

• Animals use O2 and produce CO2

• Decomposition uses O2 and produces CO2

• Around 500 m water runs out of oxygen

–Bacteria and other animals are using it during decomposition and respiration

–No photosynthesis at this depth

• Animals in this region and lower have large gills, modified hemoglobin or are inactive

Gas Exchange and Carbon Cycle• Oceans absorb and store large amounts of CO2

– Contain about 50 X the amount found in the atmosphere

• biological pump -some of the absorbed CO2 is used in the food web by phytoplankton, or used to make shells and then consumed and pooped out

• gas is trapped in the deep ocean (sequestered) until brought to surface by currents

Ocean Acidification

• CO2 is changed to carbonic acid as it dissolves in seawater– More CO2 dissolving, more acidic ocean is

becoming– 30% increase in acidity since IR

• Marine life that produce calcium carbonate shells are negatively impacted by increasing acidity (coral, clams, mussels, oysters, some algae)

• The photos below show what happens to a pteropod’s shell when placed in sea water with pH and carbonate levels projected for the year 2100. The shell slowly dissolves after 45 days.  Photo credit: Used with permission, National Geographic Images

Dissolved Salts• Dissolved salts/ minerals come from land and

underwater volcanic activity

• Average salinity is 35 parts per thousand

• Salts change water density and differences in density contribute to the creation of water masses and deep ocean circulation

• Thermohaline circulation, also called the Global Ocean Conveyor, moves water between the deep and surface ocean worldwide

Figure 1: Relative proportions of dissolved salts in seawater. (Source: PhysicalGeography.net)

• Thermohaline circulation, also called the Global Ocean Conveyor, moves water between the deep and surface ocean worldwide.Click on image for full sizeImage courtesy Argonne National Laboratory

• Image courtesy Argonne National Laboratory

Marine vertebrates control internal salt and water concentration by osmoregulation

http://marinebio.org/oceans/ocean-chemistry.asp

Climate: temperature, light, pressure

• Ocean conditions vary with depth and with latitude

http://climate.lanl.gov/

http://geosci.sfsu.edu/courses/geol102/ex9.html

• http://geosci.sfsu.edu/courses/geol102/ex9.html

Animal Adaptations and Pressure

• Ocean life has adapted to deep ocean and 1000x our pressure with lightweight skeletons, little musculature, and reduced metabolic, growth and reproductive rates.

• Diving mammals have rib cages that collapse and expand in result to changing pressure

                                             

Yelloweye rockfish with barotrauma. Shows esophagus protruding from mouth and bulging eyes (exophthalmia). (Credit: Image courtesy of Oregon State University)

Water Depth vs Light

• Photosynthetic organisms use light to make sugars.

• Sunlit area (top 100 meters) contains 90% of marine life

• Colors of penetrate thru water differently

– Red light filters out first and blue light goes the furthest

– Red animals are essentially invisible in deep waters

blog.hotelclub.com cdnn.info driftline.wordpress.com

Animal Adaptations and Temperature• Average ocean temp is 3 C• Colder temps reduce the metabolic rate• In very cold waters fish have a special

protein like antifreeze to keep tissues from freezing

• Lighter colored animals stay cooler than darker colored animals and are found in warmer waters

• Some marine life have thick layers of fat to insulate their bodies

Variations in Time and Space• Characteristics of ocean water change

with depth and season

• Many marine organisms migrate daily or seasonally because of these variations

Openlibrary.org

Biotic Factors in the Ocean

• Characteristics of living things

• Diversity: How many and what types of things live there

• Interactions between living things: competition, predation, symbiosis

Characteristics of Life

• Made of cells

• Getting energy

• Growth and development

• Reproducing

• Respond to environment

• Maintaining homeostasis

Naturalseasponge.com

Diversity of Living Things

• Systematics- Groups organisms for classification and study

• Describes the evolutionary relationships between orgs

• Earliest life forms evolved in the ocean

Diversity of Living Things• Two main division are based on cell structure

• Prokaryotes – Kingdom Moneran / bacteria group– Lack a nucleus and membrane bound organelles

• Eukaryotes- All other kingdoms– Have a nucleus and membrane bound

organelles

http://io.uwinnipeg.ca/~simmons/1116/images/bactloco.gifhttp://www.biol.tsukuba.ac.jp/~inouye/ino/etc/dinoflagellates.jpg

Diversity of Living Things

• The broadest category of life starts at the top and includes one or more of the succeeding categories

• Domain of life– Kingdom

• Phylum–Class

»Order

Family

Genus and species

Diversity of Living Things

• Every organism has a two part name unique to itself-Binomial Nomenclature– Can only interbreed with other organisms of

its kind

• Genus species or Genus species– Prevents confusion if a species is known by

many common names

• Example: Common dolphin is known as Delphinus delphis

Interaction Between Living Things

• Competition– A habitat can only support a fixed number of

individuals• Limits on space, nutrients, mates etc..

– May result in extinction of a species or niche segregation ( both species become more specialized and can then coexist)

– Winners and losers change based on varoius factors like stability of ecosystem, predation

Interaction Between Living Things

• Predation- one organism hunts, kills and eats another organism– Over time prey evolve adaptations to avoid

predation which prey must adapt to as well– Arms race between two organisms

• Important in culling weak or sick animals from the population

• Some are keystone species which promote the diversity of species in a habitat

eyesonafrica.net

Interactions between living things

• Symbiosis- living together of unlike organisms– Mutualistic- Both species benefit from the

relationship• Remora and shark: remora gets food scraps,

shark has parasites removed

michaelmcfadyenscuba.info

– Commensal- one species benefits and the other has no benefit or harm

• Hermit crab and a snail (shell)

myfishtanks.info

– Parasitic- one species benefits but the other is harmed

• Female and male anglerfish

s15.zetaboards.com

http://www.marineparasites.com/gallery.html#44