Class nº 2. Luis Chícharo

Transcription

1 DYNAMICS OF AQUATIC ECOSYSTEMS SET 2011 Class nº 2 Luis Chícharo (lchichar@ualg.pt)

2 QUESTIONS TO DISCUSS: 5 MAJOR CAUSES OF AQAUTIC ECOSYSTE DYNAMIC 5 MAJOR THREATS TO AQUATIC ECOSYSTEMS 5 MAJOR IMPACTS ON AQUATIC ECOSYSTEMS 3 TYPES OF SOLUTIONS FOR RESTORING AQUATIC ECOSYSTEMS GROUP DISCUSSION 4-5 STUDENTS SEND REPLIES BY TO LCHICHAR@UALG.PT

3

4 Solutions Population awareness Environmental education Human impacts reduction Fisheries regulation Resources management Global warming Pollution Nutrient load overfishing Wind Tides currents Latitude Input of freshwater Salinity Upwelling and downwelling Climate Human interactions/intervention Changes in Trophic levels/ Shift in foodwebs Nutrient conc Interaction dif species Primary productivity Hydrologic processes Geo natural processes Natural events catastrophes Sediments Coral bleaching Eutrophication Pressures/causes Acidification HABs Alien species Biodiversity reduction Migration patterns New diseases Threats/Impacts Mutation Creation of protected areas Conservation Restoration

5 Etymologically the word ecosystem derives from the Greek oikos, meaning "home," and systema, or "system." Nineteenth- and early 20th-century ecologists, who were well aware of the complex interdependence of living and nonliving matter, coined several terms, such as biocoenosis, microcosm, holocoen, biosystem and geobiocoenosis. It was not until British ecologist A.G. Tansley proposed the word "ecosystem" (1935) that American Raymond L. Lindeman offered the now classic definition (1942). Ecosystems are composed of a variety Ecosystems are composed of a variety of abiotic and biotic components that function in an interrelated way. WHAT IS AN ECOSYSTEM?

6 WHAT ARE AQUATIC ECOSYSTEMS? Basic ecological unit composed of living and non-living elements interacting ti in an aqueous milieu Any watery environment, such as rivers, lakes, wetlands, and estuaries, in which plants and animals interact with the chemical and physical features of the environment WATER PHYSICAL-CHEMICAL SC C C CHARACTERISTICS C CS + BIOTA COMMUNITIES

7 COMMENT THIS DEFINITION Ecosystem - A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed) DO YOU AGREE? HOW WOULD YOU DEFINE ECOSYSTEM?

8 WHAT ARE AQUATIC ECOSYSTEMS? Freshwater lake ecosystem Artic ecosystem Ocean beach ecosystem Temporary ponds ecosystem WHAT BONDS THEM TOGETHER?

9 WATER CYCLE RESIDENCE TIME AND LONG TERM ROBUSTNESS Estimated Flows of Water in the Global Water Cycle Flows given in units of kg/year Inventory of Total amount of water: 1,385, x kg Residence times Data from Chahine, 1992, The hydrological cycle and its influence on climate, Nature, v. 359, p ;

10 AQUATIC ECOSYSTEMS REQUIREMENTS..? NEED TO BE PERMANENT? and...temporary LAGOONS, PONDS NATURAL OR ARTIFICIAL? and...lakes FROM DAMS PRESENT STABLE CHARACTERISTICS? IS A MINIMUM OR MAXIMUM SIZE? and...estuaries and...small PONDS / OCEAN NEED TO BE IN PRISTINE FOR and CHRONIC POLLUTION FUNCTIONING? HIGH VARIABILITY IN SPATIAL, TEMPORAL, BIOTIC AND ABIOTIC FEATURES

11 Actual status of water resources and Global pressures on aquatic ecosystems

12 Freshwater availability for humans and Ecosystems Only 3% of Earth s water is freshwater, and only 0.03% 03% is both accessible and suitable for human use (Bhandari, 2003).

13 THE ALLERTS Global freshwater consumption rose sixfold between 1900 and more than twice the rate of population growth. About one third of the world's population already lives in countries considered to be 'water stressed' - that is, where consumption exceeds 10% of total supply. If present trends continue, two out of every three people on Earth will live in that condition by Kofi Annan, in We The People, 2000 ANTHROPOCEN ERA

14 Human pressure on aquatic ecosystems Map of Africa, Europe, and Asia shows projected population change for This map was developed by the Center for Climate Systems Research (CCSR) of the Earth Institute at Columbia University shows the human migration to the coast. Credit: Stuart Gaffin, Lee Hachadoorian, and Robert Engelman