Upcoming Events of Interest

Transcription

1 Ecosystems 31 January th class meeting Sky Islands El Nino Ecosystems 31 Jan READINGS: Sky Islands, El Nino (on website) EO Wilson book chapter Friday 02 Feb: EO Wilson book chapter (same as above) Upcoming Events of Interest Free Screening of An Inconvenient Truth with a Panel Discussion by UA Climate Scientists (ISPE) Wednesday, January 31, noon Gallagher Theater, Student Union Not eligible for Current Events assignment! Environmental Biology (ECOL 206) University of Arizona, spring 2007 Kevin Bonine, Ph.D. Anna Tyler, Graduate TA Lab 31 Jan/ 02 Feb: Ecological Footprint (link and instructions on website) Lab 07/09 Feb: Meet in lab, then outside See assignment on webpage Quiz (include name, date, and day of lab) 1. Based on the website you looked over for class, explain El Nino. 2. From your reading for today, describe what is meant by the term keystone species. 3. Define the term ecosystem service as used in this class. 4. What are you planning to create for your creativity assignment in this course? 3 4 Rocky Mountains Sierra Madres Basin and Range Biomes Sky Islands, within Desert or Grassland Seas 1000 feet elevation 3 F drop in temperature 300 miles toward Canada

2 Fir Forest in age of Global Heating? Thick-billed parrots in Arizona? 7 8 Panthera onca El Niño is an oscillation of the ocean-atmosphere system in the tropical Pacific In normal, non-el Niño conditions, the trade winds blow towards the west across the tropical Pacific. These winds pile up warm surface water in the west Pacific, so that the sea surface is about 1/2 meter higher at Indonesia than at Ecuador. The sea surface temperature is about 8 degrees C higher in the west, with cool temperatures off South America, due to an upwelling of cold water from deeper levels. This cold water is nutrient-rich, supporting high levels of primary productivity, diverse marine ecosystems, and major fisheries. Rainfall is found in rising air over the warmest water, and the east Pacific is relatively dry. Normal Conditions: El Nino Conditions:

3 During El Niño, the trade winds relax in the central and western Pacific leading to a depression of the thermocline in the eastern Pacific, and an elevation of the thermocline in the west. This reduces the efficiency of upwelling to cool the surface and cuts off the supply of nutrient rich thermocline water to the euphotic zone. The result is a rise in sea surface temperature and a drastic decline in primary productivity, the latter of which adversely affects higher trophic levels of the food chain, including commercial fisheries in this region. The weakening of easterly tradewinds during El Niño is evident as well. Rainfall follows the warm water eastward, with associated flooding in Peru and drought in Indonesia and Australia. The eastward displacement of the atmospheric heat source overlaying the warmest water results in large changes in the global atmospheric circulation, which in turn force changes in weather in regions far removed from the tropical Pacific. 13 Wind to East from West Flooding in Peru and SW US, Drought in Australia and Indonesia 14 Galapagos Islands, Ecuador Genovesa Galapagos Humboldt Current Fernandina And Isabela Pough et al Plate Tectonics Galapagos Islands, Ecuador Genovesa Fernandina And Isabela Nazca Plate Andes

4 Only lizard to feed at sea -algae, seaweed Galapagos Marine Iguana (Iguanidae) Up to 10 or 12 m deep Up to a hour-long dives for large males (Darwin shipmate) Highly social 8,000 indivs/ km of coast 16 islands Cold upwelling water nourishes algae Fernandina/Isabela males to 10+ kg females to almost 3 kg Genovesa males only to 1 kg females to < 1kg Why? Amblyrhynchus cristatus Water temperature and current strength Katrina Mangin 22 Galapagos Marine Iguana (Iguanidae)

5 El Nino lack of food (Why?) Galapagos Marine Iguana (Iguanidae) Starvation b/c high cost of salt excretion Animals may lose 15% body length -bone absorption Only adult vertebrate known to regularly shrink (astronauts) Largest animals die -sexual selection -natural selection Repro Success? Amblyrhynchus cristatus Weather vs. Climate Le Climate Miller, Temperature 2. Precipitation Latitude Altitude Currents - Not just people, but ecosystems and species as well 29 Miller, 2003 (see Miller 2005 Fig. 12-2) 30 5

6 Prevailing Winds Global Air Circulation -6 Hadley Cells Movement of Heat and Moisture -Warm Air Rises - Cool Air Sinks - Warm Air Holds More Water Vapor - When it cools = Precipitation Earth Rotates Global Distribution of: -Forests - Grasslands - Deserts ~ Tropics Miller, 2003 (see Miller 2005, Fig. 12-3) Miller, 2003 (see Miller 2005, Fig. 12-3) Beech Tree Range - poles will heat up relatively faster For each 1 degree C change: - climate belts will shift toward the poles by km Miller, 2003, see Miller 2005 Fig Rain shadow