Biology 13- Marine Biology

Transcription

1 Introductions Biology 13- Marine Biology Instructor: Dr. Kevin Raskoff Phone: (831) Office: Life Science, 203B (upstairs) Office hours: Mon-Thurs ; Thur 5-6pm; or by arrangement. The class website can be found at I can t remember that!!!! How else can I find it?! Class Introductions Name Academic plan Why are you here? What is your comfort with science? Something interesting about yourself. Review of Syllabus What should you expect of this class? What do I expect of you? What should you expect of yourself? What is this class about? Class Website Can t find it? Google Raskoff I m going to get my textbook: A. New B. Used C. From the Library D. Book? I have to read?! 1

2 Class Roster So, what do you want to learn about in Marine Biology? Why is the ocean blue? Teahupo'o, Tahiti What the Is this Marine Abiology?! 2

3 Arctic Ctenophores Pelagic Snails Amphipods The Wonderful World of Mucus! How smart are Fishes? Oceanic Nekton 3

4 Marine Lakes Land-locked marine ecosystems Greatly simplified flora and fauna H 2 S- Hydrogen Sulfide layer Subs And ROVs The Water! Molecular basics a review Physics of water Salinity Density Pressure ph Dissolved Gases What is one of the most important things in marine biology? Lets looks at some water How is it made? Properties Phases Dissolving power What is a salt? How does it do it? What does it do to the water? What does temperature do? Elements and Compounds Salt Lets look at some water 4

5 Chemical Reactions Polar covalent bonds in a water molecule 2H 2 + O 2 = 2H 2 0 Electronegativity: a measure of an atom s selfishness, that is its ability to hold electrons. Oxygen holds onto the electrons more, so it has a negative (-) charge, so the Hydrogen are positive (+) OK, so what! I thought this was Marine Biology!! Polar molecules can be weakly attracted to each other and form Hydrogen Bonds Hydrogen Bonds The Magic of Water 1. Cohesion and Adhesion Water is attracted to other water (Co), and to other things (Ad) by the polar charges in the molecule These Hydrogen (or Polar) Bonds give water a lot of interesting and important properties that matter to LIFE. The Magic of Water 2. High heat capacity 3. High heat of evaporation 4. High thermal conductivity 5. Less dense when frozen Makes it a very Stable environment for life The Magic of Water 6. Excellent biological solvent Solvent and solute Water can dissolve most things, in bodies and ocean NaCl vs. Na and Cl So? 5

6 Test your understanding Positively charged sodium and negatively charged chloride are examples of A. hydrogen bonds B. ions C. molecules D. atoms Test your understanding Hydrogen bonds in water molecules are formed between A. hydrogen atoms of adjacent molecules. B. oxygen atoms of adjacent molecules. C. hydrogen and oxygen atoms of adjacent molecules. D. two hydrogen atoms of the same molecule. E. two oxygen atoms of the same molecule. Chemical Dissociation Salts, Acids, and Bases ph a scale to measure acidity or alkalinity Water is a great Buffer: compounds that minimize changes in ph by binding excess H+ or OH- ions. World Ocean range: Slightly Basic for now. The ocean is getting more acidic! Why?! Ocean ph Dissolved Gasses Carbon Dioxide in water The amount of gas dissolved in water (Gas Solubility) varies by temperature- cold water holds more gas Oxygen and CO 2 concentrations vary greatly by depth and region Water has low Oxygen, but high CO 2 Lets draw a graph CO 2 + H 2 O H 2 CO 3 H + + HCO 3- H + + CO 3 2- Carbon Water Carbonic bicarbonate carbonate Dioxide Acid Bicarbonate ion is the major reservoir of CO 2 in the sea. (7 th most common ion), and a BIG Buffer About 50x more CO 2 in water than in air! Why??? Have you heard about CO 2 anywhere else? Know this stuff! This will be important! In this class and you life. 6

7 The Acid Ocean While we worry over atmospheric climate change, the real crisis of the 21 st century will probably be in the Ocean. The battlefield of that crisis is the Pacific, and Monterey Bay is Ground Zero. What will be the ecology of the acid ocean? How will the food chain be altered? What management practices will need to be changed? Ocean Acidification The oceans absorb most of our CO 2 emissions When CO 2 dissolves into the water it form Carbonic Acid. Additional stresses for animals that are already food-limited Living on the edge Data from Jim Barry, MBARI Depth (m) ph variation in the Pacific Ocean Central Pacific Western Pacific North Pacific Antarctic Pacific Eastern Pacific Future Ocean Food Web Loss of biodiversity, low productivity, dominated by microbial recycling? Primary Producers Sinking Organic Debris What are the expected effects of An acidified Ocean? Zooplankton food web Upper Trophic levels Test your understanding Explain the fate of CO 2 in the ocean. In your explanation address the 3 carbon dioxide reservoirs in the sea, which form is most of the CO 2 found, and the impact on ocean ph of increasing atmospheric CO 2 concentrations Simplified Food Web, Increased Microbial Dominance Seafloor community Microbial Remineralization Salinity Salinity Total concentration of dissolved inorganic solids Ocean water varies from 3.3% to 3.7%, but we usually talk about ppt or. Average=3.5% (33 to 37 ppt, PSU, or unit-less) Major Constituents of seawater (top 6) Chloride (Cl - ) = 55.04% Sodium (Na + ) = 30.61% Sulfate (SO 2-4 ) = 7.68% Magnesium (Mg 2+ ) = 3.69% Calcium (Ca 2+ ) = 1.16% Potassium (K + ) = 1.10% total 99.28% About 2.2 lbs of salt in 1 cu ft. of water, which is about 2 tbsp/liter Trace Ions Several trace elements can also be limiting, these are called micronutrient most notably is iron and Si. Other metals like Cd, Zn, Ni, Cu, Se are depleted in surface waters Principle of Constant Proportions Early studies: found total salinity varied (as water is added and removed), but ratio of one major ion to another was constant throughout the ocean. 7

8 Where does the salt come from? Test your understanding The average salinity of seawater in the open ocean is A. 30 B. 33 C. 35 D. 40 The Ocean is getting: A. Fresher B. Saltier C. Staying about the same Temperature and Density Temperature and Solar Energy Density is factor of salinity and temperature D = Mass / Volume Clines in the Ocean Physical Environment Clines of all sorts structure the open water habitat. Regions of rapid change. Temp, salinity, oxygen, nutrients, etc 8

9 Figure 3.15b Pressure Product of: Depth Salinity Temperature Dissolved Items Atmospheric Pressure An animal living at 100 meters deals with a pressure of: A. 5 ATM B. 9 ATM C. 10 ATM D. 11 ATM Light in the ocean White light is made of all the colors Physical- Light Variation in wavelengths through water Compensation Depth 1% surface intensity PAR- Photosynthetically Available Radiation Count available photons, not just all wavelengths Where does the light go? Light is Scattered by: Suspended particles (Sediment soil, plankton, etc.) Dissolved material Light is Absorbed by: Phytoplankton: used in photosynthesis, converted to chemical energy Water molecules: converted to heat This scattering and absorption impact the colors differently 9

10 Measuring Water Clarity Secchi Disk Other more complicated methods So Why is the ocean blue? The rates of scattering and absorption are LOWEST for blue, so blue light makes it down to greater depths and is more available for reflecting back to the surface. Importance of light in the sea Sunlight absorbed by the water is converted to heat. This heat warms the upper portions of the water. It also provides the energy for evaporation and the winds. Photosynthesizing organisms ( plants ) are the main source of the food in the ocean! The depth at which light penetrates the ocean controls the depth to which these organisms can occur. This zone is called the Photic Zone. Other biological impacts of light Light influenced movement Daily Vertical Migration Many different groups of animals migrate up and down in the water with the changing light intensity. They typically come up to the surface to feed at night, then swim back down at dawn to escape their predators. Many swim 100s of meters a night. Coloration of animals In the open ocean there is no where to hide! Many animals have evolved interesting ways to deal with this issue using color. In deeper waters many animals are brightly colored Red, orange, and yellow are particularly popular. Animals which are red, yellow, or even green would look black with the available light. 10

11 With time of day With other biomass With turbidity With season Intensity changes 11