Test #2 Results by Next Week. Chapter 10: Biological Productivity

Test #2 Results by Next Week

Chapter 10:Biological Productivity

Conditions for Life in the Sea

Consider the main biochemical reaction for life in the sea, and on earth in general:

6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2

Focus on left side of equation

What is in short supply in the sea and thus limits the amount of life in the ocean??

Absorbing Nutrients 6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2

Phytoplankton are base of the food chain

Most important primary producers of complex sugars and oxygen

Lauderia sp.

The Marine Food Web

Absorbing Nutrients Nutrients absorbed by

plants through diffusion across a semi-permeable membrane

Lauderia sp.

Diffusion:molecules move from high to low concentrations

Which Nutrients are in Short Supply?

Nitrogen (N) as Nitrate NO3 (-2)

Phosphorus (P) as Phosphate PO4 (-2)

Silicon (Si) as Silicate SiO4 (-2)

Phosphate and Nitrate in the Pacific

Silicate in the Pacific

Biolimiting Nutrients N, P, and Si are exhausted first in Eq.

surface waters during photosynthesis Essential to the growth of phytoplankton If these biolimiting nutrients increase in

sea water, life increases If these biolimiting nutrients decrease in

sea water, life decreases Where would you expect to find the

highest biomass in the Pacific??

CZCS Global Primary Production

How Does Nutrient Distribution Compare w/Dissolved Oxygen?

Dissolved O2 Reverse of Nutrients

O2 is high in the surface and mixed layer

O2 decreases to a minimum at base of thermocline

O2 then steadily increases with depth

Why is the Concentration of Oxygen High in the Mixed Layer??

Hint #1: How and where is oxygen produced in the sea???6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2

Hint #2: How can oxygen be mixed downward from the atmosphere into the ocean?

How is Oxygen Removed from the Thermocline & Slightly Below??

Dead and decaying organic matter sinks downward from surface waters

Rate of sinking decreases as it encounters the cold, dense water of the thermocline

Material decays (oxidizes) at the thermocline, which strips O2 out of the water and returns nutrients to the sea

Cold, nutrient-rich water of the thermocline is returned to sunlit surface waters by way of upwelling

CZCS Global Primary Production

Marine Ecology

Chapter 9

Classification of Organisms by Environment

horizontal: neritic | oceanic vertical:

– epipelagic (top) / euphotic (good)

– mesopelagic (middle) / disphotic (low)

– bathypelagic (deep) / aphotic (without)

– abyssopelagic (“bottomless”)

Divisions of the Marine EnvironmentFigure 9-1

Classification of Organismsby Lifestyle

Scientists have established another classification scheme to categorize biota on the basis of lifestyle. The major groups are:

– plankton (floaters)

– nekton (swimmers)

– benthos (bottom dwellers)

Plankton Plankton are weak swimmers, and are

known as drifters, unable to counteract currents. The group includes:

– Phytoplankton (plants)

– Zooplankton (animals)

Nekton Nekton are active swimmers capable

of counteracting currents. The group includes a diversity of organisms including:– Fish– Squids– Reptiles– Birds– Mammals

Distribution of Marine Lifestyles

16.7% of Earth’s animals are marine 2% inhabit pelagic environment (most of

the oceans are cold and dark) 98% are benthic!

Benthos

The benthos includes organisms attached to or living on or in the sea bed. This group includes plants and animals. – Epiflora or epifauna live on the sea bottom.– Infauna live in the sea bottom.

Benthic plants are restricted to shallow waters because of their requirement for light.

Benthic animals occur everywhere from shallow depths to the deep sea.

Basic Ecology physical and chemical parameters

distribution and abundance An ecosystem includes both the living

(biotic) and non-living (abiotic) portions of the environment.– Examples include: salt marshes, estuaries,

coral reefs, the North Pacific Gyre.

TemperatureFigure 9-10

controls rates of chemical reactions and thus metabolic rates, growth rates, feeding rates, etc.

Salinity Salinity is a basic property of seawater

and it too affects marine organisms.

– Many of the elements in seawater are utilized by marine organisms for growth.

– Salinity tolerance is also important in limiting distribution.

Diffusion:molecules move from high to low concentrations

Diffusion/OsmoregulationFigure 9-12

Some organisms can regulate the movement of water into and out of the cells by osmoregulation.

Hydrostatic Pressure

Pressure caused by the height of water. Function of water height and water density Pressure generally increases at a rate of 1

atm per 10 m of water.

( or 16 psi per 10 m depth)

Think You’re Under Pressure Now?

Hydrostatic Pressure(Cont.)

enormous in the deep sea yet animals live there.

Animals do not contain gases. However, mesopelagic fish which have

gas-filled swim bladders to help maintain neutral buoyancy – unable to move rapidly between depths– pressure change could cause bladder explode.

Oregon Coast Field Trip - Oregon Coast Field Trip - Sat., May 21st Sat., May 21st

dusk.geo.orst.edu/oceans/field.htmldusk.geo.orst.edu/oceans/field.html Be here by 7:00 a.m.Be here by 7:00 a.m. 7:15 - Busses 7:15 - Busses leaveleave from from

Wilkinson lotWilkinson lot 8:30 - Seal Rock volcanic 8:30 - Seal Rock volcanic

rocks and tide poolsrocks and tide pools 11:00 - Lunch at Seal Rock 11:00 - Lunch at Seal Rock

park park (bring your own)(bring your own)

12:00 - HMSC 12:00 - HMSC Visitor CenterVisitor Center

1:30ish - Return to 1:30ish - Return to CorvallisCorvallis

Back by 2:30-3:00Back by 2:30-3:00

Required Field Trip GuideRequired Field Trip Guidedusk.geo.orst.edu/oceans/field.htmldusk.geo.orst.edu/oceans/field.html

Answers to bolded questions in guide Answers to bolded questions in guide

–Turn assignment in to Turn assignment in to your TAyour TA–Due by 5:00 p.m., June 3rdDue by 5:00 p.m., June 3rd

Extra Credit #1A - Climate Change Lecture

Bruce Wielicki, NASA, April 4, 2005– Not enough room in LaSells that evening

Watch DVD finally on reserve in library, VR 695– 1-page reaction paper, typed, double-spaced– Overview, your reaction, and how content relates to this course

Due by 5:00, Thursday, June 2nd

– Hand in to your TA please !!!– Worth up to 10 pts. on final exam