Robert W. Christopherson Charlie Thomsen Chapter 19 Ecosystem Essentials

Vocalic Eruption in Iceland Flight Cancellation

Earth’s Major Plates Figure Arrows represent 20 million years of movement.

The space on Earth where life exist forms a sphere which extends from ocean floor to ~8km altitude into the atmosphere. Ecosystem: A self-sustaining association of living plants, animals and microbes and their nonliving physical environment. 1) Natural ecosystems are open systems with respect to energy and matter. 2) Ecosystem boundaries often function as transition zone, not sharp demarcations. 3) Natural ecosystems can varying significantly in size Biosphere

Ecology is the study of the relationship between organisms (human beings, plants, animals, microbes) and their environment. a) the living organisms have impacts on the environment. lichens/mosses grow on rocks  soils growth of trees  add litter to soils  more fertile soil wolfs eat deer  reduce deer population  less grazing b) through altering the environment, their impacts also have feedbacks to themselves. lichens/mosses grow on rocks  soils  higher plants to grow  lichens/mosses compete out Wolfs eat deer  reduce deer population  less food for wolf  Ecology

Deforestation:  timber  economic gains  better life  more people  more space for agriculture  more food  more people  loss of other lives  loss of resources  soil erosion  land degradation  less food Agriculture  more food  more people expansion  loss of other land (grass, forest, wetland …) fertilization/pesticide  more food  pollution  disease Urban expansion  better living  more people expansion  loss of other lands Fossil fuel use  better living  more people  global warming/pollution  Humans as Most the Active Agent

Like any system in general, it is made up of several components, each function independently yet in concert. biotic individuals  population  Communities producers (plants), consumers (animals), decomposers Abiotic Ecosystem Components soils, light, heat (temperature), water, air As ecosystems are open systems, there are constant flow of energy and matter through the system to keep the system alive. Ecosystem Components

Biotic and Abiotic Components Figure 19.2

Small Leaves do the Big Job: Photosynthesis CO 2 H2OH2O Losing water is the price to pay for gaining CO 2 Plants also keep cool with transpiration (1) cools leaves (2) brings nutrients to where they are needed stoma Underside

Stomatal Regulation 1.Stoma opens when light shine on the leaf, thus opens during the day to absorb CO 2 and closes during night to prevent unnecessary water loss. 2.Stoma closes when there is limited water in the soil. 3.Stoma closes when the air is too dry, i.e. high vapor pressure deficit. 4.Stoma closes to save water when CO 2 concentration is high in the air.

Gross Primary Production and Respiration GPP: Gross Primary Production, the amount of carbohydrate (C 6 H 12 O 6 ) produced through photosynthesis is called GPP. Plant Respiration: All living organism needs energy to stay alive. Plants do too. Plants use about 50% of GPP they produce to stay alive. The respiration is the opposite process of photosynthesis. We call this respiration as autotrophic respiration (R a ). Autotrophic respiration is use for two purpose: (1) to keep living tissues alive, called maintenance respiration. (2) To realize growth, call growth respiration. Note: Energy is not heat energy as said in the textbook, but energy in the form plant can use, ATP (Adenosine Triphosphate)

Net Primary Production NPP: Net Primary Production is the balance of GPP after plant respiration (autotrophic respiration) is taken away. NPP = GPP – R a NPP is the part of photosynthesis product that can be used for growth, including Leaves Branches Stems Roots Part of NPP become food resources available for the consumers ( herbivores, carnivores, humans)

Biomass vs. Net Primary Production Biomass The dry weight of the living organisms. e.g. the total dry weight of leaves, branches, stems, and roots would be the biomass of a tree, not including the dead leaves or stems on the floor. For plants, Biomass is the accumulated NPP that stays as part of the living organism. Due to litter fall and mortality, Biomass is less than the annual NPP added up. Biomass is a cumulative figure, NPP is an annual figure. For forests, the biomass eventually levels off as the addition of growth from NPP breaks even with loss of biomass due to litter fall and mortality.

Net Primary Productivity Figure 19.7 Satellite measure of chlorophyll concentration

Carbon Cycle and Balance Figure Input: 6.3 (fossil) (landuse)=7.9 Output: =3.1 Balance: = 5.8 Actual increase seen: 3.2 Missing 2.2 C in the atmosphere: missing sink

Producers, Consumers, and Decomposers Producers: Plants on land Phytoplankton in oceans Consumers: Primary (herbivores), secondary (carnivores), tertiary (carnivores), omnivores Decomposers: bacteria and fungi Energy/Matter Flow in Ecosystems

Energy, Nutrient, and Food Pathways Figure 19.13