To be ALIVE!All life on earth is fundamentally the same—

it’s just packaged in different ways. LIFE

• Capture, Store, and Transmit ENERGY

• Reproduce

NON-LIFE

• Nothing special about the atoms or energy of life

• Nothing but the stuff on left to tell life vs. nonlife

VS.

Living matter can NOT function with out energy. Energy—the capacity to do work. Can NOT create new energy but they can????

• Plant transforms light energy into chemical energy • Animal transforms chemical energy into energy of

movement by muscles and…• Transform energy of movement into HEAT

Main source of energy for all living things on earth is the………………….

Primary productivity

• Primary productivity is the amount of carbon (organic matter) produced by organisms– Mostly through photosynthesis

• Energy source = solar radiation

– Also includes chemosynthesis• Energy source = chemical reactions

PhotosyntheticPhotosynthetic productivity

= produces ENOURMOUS quantities of = produces ENOURMOUS quantities of energyenergy

asas——VISIBILE LIGHT—VISIBILE LIGHT— whichwhich

strikes earth but only strikes earth but only one part in 2,000 one part in 2,000 is captured by organisms is captured by organisms

“tiny”

1. Light Energy is from the sun is trapped by CHLOROPHYLL

2. Chlorophyll is found in organisms called PRIMARY PRODUCERS

3. the Chlorophyll changes the energy from sun into chemical energy

4. Chemical energy is used to build simple carbohydrates and other

organic molecules—FOOD=(which then gets used by primary producers or

eaten by animals)

Photosynthesizers: Green plants and

algae, and specialized bacteria

Ligh

t Ene

rgy

Respirers:Animals and

decomposers and plants at night

To space

Chemical energy

(carbohydrates, etc.)

Energy of M

ovement,

waste heat, entropy

Producers

Consumers

• At each step energy is degraded

Chlorophyll

• Green pigment found in algae and plants that allows them to absorb energy from light

• Greek– Chloros – green– Phyllon – leaf

• http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MY1DMM_CHLORA

Primary Production

Global chlorophyll concentrations for Oct. 2000

Feb 5, 1998: uniformly low pigment concentrations during all seasons

Phyto and Zoo Plankton

• Greek

• Phyto = plant

• Zoo = animal

• Planktos = drifter; wanderer

• Phyto – autotrophs

• Zoo – heterotrophs – cannot produce own energy– Cnidarians – jellyfish– Crustaceans - krill

Primary ProducersCommon NameBlue-green algae (cyanobacteria)Red algaeBrown algaeGreen algaeCoccolithophoridsDinoflagellatesDiatomsSeagrass

Plankton Sampling

picoplankton

nanplankton

Plankton Size

microplankton

• Picoplankton (.2-2 µm) • Nanoplankton (2 - 20 µm)• Microplankton (20-200 µm)• Macroplankton (200-2,000 µm)• Megaplankton (> 2,000 µm)

NO SUN……

• Some species of bacteria and archaea• Communities at hydrothermal vents

1. Conversion of Simple Carbon molecules (CO2 & Methane) into Carbs

2. By using the oxidation of inorganic molecules (hydrogen gas, hydrogen sulfide, or methane) as a source of energy.

http://ocean.si.edu/deep-sea What lives here video

Comparison: Chemo vs Photo

Secchi Disc

• Used to measure light penetration

• Black and white disc

Secchi Disc

• Disc is lowered into water until no longer visible – depth recorded– Then slowly raised until seen again – depth

recorded– Mean of these two depths = transparency of water

• http://www.mainevolunteerlakemonitors.org/recertify/disk.php

Turbidity = clarity

Productivity• The rate of accumulation/production of biomass/energy

– Biomass = the mass of living biological organisms in an ecosystem at a given time

• Measured in terms of energy capture per unit area (or per unit volume in aquatic ecosystems) per year

• Almost all ecosystems = green plants are primary producers– Refer to primary production in relation to plants

• Consumers depend directly or indirectly on the energy captured by primary producers

• Productivity of an ecosystem affects all trophic levels

Productivity

• When conditions are favorable for photosynthesis, the productivity of the ecosystem tends to be relatively high

• Example: tropical rain forests, algal beds and reefs

Oceanic photosynthetic productivity

• Controlling factors affecting photosynthetic productivity:– Availability of nutrients

• Nitrates• Phosphates• Iron

– Amount of sunlight• Varies daily and seasonally• Sunlight strong enough to support

photosynthesis occurs only to a depth of 100 meters (euphotic zone)

Locations of maximum photosynthetic productivity

• Coastlines– Abundant supply of nutrients from land– Water shallow enough for light to penetrate

all the way to the sea floor

• Upwelling areas– Cool, nutrient-rich deep water is brought to

the sunlit surface

Upwelling

Coastal upwelling

The electromagnetic spectrum and light penetration in seawater

Water color and life in the ocean

• Ocean color is influenced by:– The amount of turbidity (cloudiness) from runoff– The amount of photosynthetic pigment, which

corresponds to the amount of productivity

• Yellow-green = highly productive water– Found in coastal and upwelling areas

(eutrophic)

• Clear indigo blue = low productivity water– Found in the tropics and open ocean

(oligotrophic)

Table 1. Average net primary production and biomass of aquatic habitats. Data from R.H. Whittaker and G.E. Likens, Human Ecol. 1: 357-369 (1973).

Habitat Net primary Production

(g C/m2/yr)

Coral Reefs 2000

Kelp Bed 1900

Estuaries 1800

Seagrass Beds 1000

Mangrove Swamp 500

Lakes & streams 500

Continental Shelf 360

Upwelling 250

Open ocean 50

Productivity varies TEMPORALLY and SPATIALLY:

• generally highest over continental shelves; over the shelf itself it is highest just offshore

• seasonality more pronounced at high latitudes• at mid latitudes, productivity peaks both spring

and fall

Observations from September 1997 through July 2005

Regional productivity

• Photosynthetic productivity varies due to:

– Amount of sunlight – Availability of nutrients

• Thermocline (a layer of rapidly changing temperature) limits nutrient supply

• Examine three open ocean regions:1. Polar oceans (>60° latitude)2. Tropical oceans (<30° latitude)3. Temperate oceans (30-60° latitude)

Productivity in tropical, temperate, and polar oceans

Zooplankton

Productivity polar oceans

Productivity in tropical oceans

Productivity in temperate oceans

R=P

Primary Productivity• Gross Primary Productivity (GPP)

– The rate of production of organic matter from inorganic materials by autotrophic organisms

• Respiration (R)– The rate of consumption of organic matter

(conversion to inorganic matter) by organisms.

• Net Primary Productivity (NPP)– The net rate of organic matter produced as a

consequence of both GPP and R.

Primary Productivity

NPP = GPP - R

Light & Dark Experiments

Photosynthesis:light + 6CO2 + 6H2O C6H12O6 + 6O2

Respiration:C6H12O6 + 6O2

zooplanktonphytoplankton

decomposition6CO2 + 6H2O

Calculating Primary Productivity

(Light - Initial) = (10 - 8) = 2 mg/L/hr = (GPP - R) = NPP

(Initial - Dark) = (8 - 5) = 3 mg/L/hr = Respiration

(Light - Dark) = (10 - 5) = 5 mg/L/hr = (NPP + R) = GPP

Assume that our incubation period was 1 hour.

Measured oxygen concentrations:

Initial bottle = 8 mg O2 /L

Light bottle = 10 mg O2 /L

Dark bottle = 5 mg O2 /L

dark bottle light bottle

photosynthesis + respirationrespiration

weight

Energy Losses Along Food Chains

• 3 reasons:– Respiration/heat– Waste/feces

• Excretion (feces) or egestion (from cells)

– Some parts of organism not eaten

• Of total energy from Sun, only a small percentage is captured and used for synthesis (NOT ALL ENERGY BECOMES AVAILABLE AS NET PRODUCTION)– Reflected back from surfaces– Pass straight through a

producer – not absorbed– Inefficiencies of

photosynthesis– NPP = GPP – R

…the energy consumed by the herbivore include heat from

1.Respiration 2.Losses in urine and undigested plant material in feces3.Growth

Energy Flow in a Food Chain

BIG reason why RARELY have more than 5 levels

• Energy losses between trophic levels

• “loss of heat energy”

• Insufficient energy available to transfer to more than 5 trophic levels

Efficiency of Energy transfer between trophic levels

• Net productivity of plants in a food chain is 36,000 kJ/m2 per year

• Net production of herbivores is 1,700 kJ/m2 per year

• Efficiency of transfer of energy from the producers to herbivores

(1,700 / 36,000) x 100 = 4.72%• Energy losses: heat from respiration, losses in

urine, undigested plant material (fecal matter)• Energy of production of herbivores represent total

energy available to carnivores (next trophic level)

Example

• 3.5%

• Show work! [1 point]

• Productivity can be measured as mass of carbon incorporated into biological molecules per unit area per unit time

• The primary productivity of the phytoplankton in this food web is 90 g of carbon per m2 per year.

• The efficiency of transfer between phytoplankton and herbivores is approximately 10%.

• Assuming that zooplankton and bottom-feeding herbivores eat equal quantities of phytoplankton, calculate the amount of carbon incorporated into zooplankton per m2 per year. Show your working.

• ....................................................... g C m–2 year–1 [2]

• Answer: 90/10% = 9/2 = 4.5

Ecological Pyramids

• Graphical representation of food chain

• Producers at base– Horizontal bars represents successive trophic

levels

• Width of bar proportional to numbers, biomass or energy– Impossible to have more energy in higher

trophic levels

Ecological Pyramid

A pyramid of NUMBERS shows the relative number of organisms at each stage of a food chain.

• Sometimes a pyramid of numbers is not the best way to represent a food chain.

A pyramid of BIOMASS shows the total mass of organisms at each stage of a food chain. • all producers have a higher biomass than the primary

consumer, so a pyramid will always be produced. • The total energy (and biomass) present at a lower tier of

the pyramid, must be greater than the higher tiers in order to support the energy requirements of the subsequent organisms.

• It is possible to have inverted pyramids of numbers and biomass, but pyramids of energy are always the ‘right way up’ because it is impossible to have more energy in higher trophic level than in a lower trophic level.

Example

• Draw a pyramid of biomass for the following food chain:

Phytoplankon krill fish penguins killer whales [2]

Answer:

• pyramid with 5 levels;

• each level named; (trophic)

1st trophic level

2nd2nd, 3rd

3rd, 4th, 5th 3rd, 4th , 5th

4th, 5th, 6th

4th, 5th, 6th, 7th

4th, 5th, 6th

3rd, 4th, 5th

4th, 5th, 6th

3rd, 4th

1st trophic level

2nd

2nd3rd, 4th

3rd

3rd3rd, 4th

3rd, 4th, 5th4th, 5th

Practice:

Net Productivity of plants in a food chain is 36,000 KJ per m2 per yearNet production of herbivores is 1700 KJ per m2 per year

Efficiency of energy transfer from the producers to the herbivores is…

(1700 / 36000) x 100= 4.72%

Inquiry1. Why is the open ocean a biological desert?2. Where are the most productive regions located?3. Describe productivity in temperate, polar and

tropical water.4. Why does the zooplankton lag behind the

phytoplankton?5. If you want to catch microplankton, what size mesh

net do you need?6. Why can’t plants grow below the compensation

depth?7. Why does eutrophication sometimes result in mass

fish kills?