Introduction to Ecosystems It is inconceivable to me that an ethical relation to land can exist without love, respect,

1. Introduction to Ecosystems�It is inconceivable to me that an ethical relation to land can exist without love, respect, and admiration for land, and a high regard for its value; I mean value in the philosophical sense."Aldo Leopold, 1949

3. What is an Ecosystem? The ecosystem concept: all the organisms (a community of species) along with all the components of the abiotic environment, interacting together as a system, within spatial boundaries Biological community (biotic) Physical environment (abiotic) Ecosystem: a biological community and its physical environment Biological community is made up of the living things For example: all the living organisms in a pond�the phytoplankton, cattails, fish, frogs, dragonflies, etc. Physical community is the non-living component For example: sunlight, which the plants depend on for photosynthesis Water, minerals, airEcosystem: a biological community and its physical environment Biological community is made up of the living things For example: all the living organisms in a pond�the phytoplankton, cattails, fish, frogs, dragonflies, etc. Physical community is the non-living component For example: sunlight, which the plants depend on for photosynthesis Water, minerals, air

4. How big is an ecosystem?When studying an ecosystem�size does matter.

6. Ecosystem Components BIOTIC AND ABIOTIC BOUNDARIES (SCALE) FLUX AND CYCLING CHANGE WITH TIME HISTORY Ecosystem inputs and outputs represent connections to adjacent ecosystems, and to larger, global cycles

7. The Hudson as an Ecosystem Watershed concept: area of land where all the water under it or that drains off it goes to the same place Land that goes into the Hudson drains 13,400 square miles River itself: 315 miles long View the watershed module from http://www.meted.ucar.edu/broadcastmet/watershed/ to help students visualize a watershed. View the watershed module from http://www.meted.ucar.edu/broadcastmet/watershed/ to help students visualize a watershed.

8. What�s special about it? Its an estuary What affects an estuary? Why is this important?

9. The Hudson River experiences tides all the way to the Troy dam

10. Location of the salt front: change depends on�? The salt front is where the last measureable amount of salt is found in the river on any given day. It depends on tides, currents, wind, and rainfall. The salt front is where the last measureable amount of salt is found in the river on any given day. It depends on tides, currents, wind, and rainfall.

12. Freshwater tidal Hudson

13. The Hudson, as an estuary, is very productive�what does this mean?

14. What is productivity? Productivity: growth rate of all living things Primary productivity: growth rate of producers Solar energy converted to organic matter (biomass) Stored in living organisms What are the primary producers in the Hudson? Important because all organisms depend on primary producers for their energy supply Usually measured as grams of carbon per square meter-WHY??? Primary production is consumed, converted to detritus, or accumulated in biomass Ecologists like to talk about the productivity of ecosystems, that is, the amount of solar energy that is stored in living organisms Some ecosystems are more efficient at storing energy than others Let�s look at this figure Ecologists like to talk about the productivity of ecosystems, that is, the amount of solar energy that is stored in living organisms Some ecosystems are more efficient at storing energy than others Let�s look at this figure

15. Producers in the Hudson . Because primary producers make oxygen and consume carbon dioxide, we can estimate primary production by measuring the amount of oxygen that is produced (or carbon dioxide that is consumed) in a bottle or in a section of the river. Alternatively, we can add a little14-carbon, which is radioactive, to a bottle of water, and measure the amount of radioactivity that is picked up by phytoplankton. Production of bacteria is also estimated by measuring the uptake of radioactive nucleic acids or amino acids. . Because primary producers make oxygen and consume carbon dioxide, we can estimate primary production by measuring the amount of oxygen that is produced (or carbon dioxide that is consumed) in a bottle or in a section of the river. Alternatively, we can add a little14-carbon, which is radioactive, to a bottle of water, and measure the amount of radioactivity that is picked up by phytoplankton. Production of bacteria is also estimated by measuring the uptake of radioactive nucleic acids or amino acids.

16. What controls productivity? �Limiting factors� - Too much or too little of any abiotic factor can limit or prevent growth of a population What could be a limiting factor in the Hudson?

17. What controls primary productivity in the Hudson? River flow: too much water Light: not enough, and they can�t grow Predators: grazers Every part of the food web will have different controls

18. Productivity in the Hudson Dramatic changes after the arrival of zebra mussels in the freshwater parts of the river (zebra mussels are intolerant of salt) Phytoplankton production before: 50 gC/m2-yr after: 7 gC/m2-yr

19. What drives ecosystems? Producers: where do they get their energy? Photosynthesis vs Respiration: graph from Hudson River Green plants capture energy from the sun Part of the physical environment Use sun�s energy to carry out photosynthesis Carbon dioxide and water are converted to organic compounds (glucose) and oxygen Energy from the sun is now stored in bonds between the atoms that make up new organic compounds Photosynthesis is referred to as primary productivity Plants are primary producers Green plants capture energy from the sun Part of the physical environment Use sun�s energy to carry out photosynthesis Carbon dioxide and water are converted to organic compounds (glucose) and oxygen Energy from the sun is now stored in bonds between the atoms that make up new organic compounds Photosynthesis is referred to as primary productivity Plants are primary producers

20. Energy in Ecosystems Herbivores, carnivores, omnivores All consumers use plants as food, either primarily or secondarily Other organisms eat these plants for food Need energy which comes from food Break bonds to get this energy using cellular respirationOther organisms eat these plants for food Need energy which comes from food Break bonds to get this energy using cellular respiration

21. What happens to the useable energy from one level to the next?

22. Food pyramids can be deceptive�

23. Organisms and Energy Decomposers and Detritivores Use nonliving organic matter for energy Fungi, bacteria Detritus: dead and decaying organic material Decomposers also need energy Get it from nonliving organic matter�still energy in bonds Break down organic matter via cellular respiration Release energy, water and carbon dioxide Trophic levels: an organism�s feeding position in an ecosystems For example: primary producer, primary consumer, secondary consumerDecomposers also need energy Get it from nonliving organic matter�still energy in bonds Break down organic matter via cellular respiration Release energy, water and carbon dioxide Trophic levels: an organism�s feeding position in an ecosystems For example: primary producer, primary consumer, secondary consumer

24. Detritus in the Hudson Detritus plays an important part in the Hudson�s energy budget Who eats detritus? What is a decomposer? An amphipod eats phytoplankton and detritus�

25. Where does detritus in the Hudson come from? Mid Hudson region: 90% of carbon compounds come from the watershed; only 10% comes from primary production Bacteria production is very high in the mid-Hudson region Lower Hudson: phytoplankton & sewage

26. Sources of Organic Carbon in the Hudson River