Lecture Goals To discuss why nitrogen and phosphorus
Lecture Goals To discuss why nitrogen and phosphorus are important nutrients in freshwater systems. To trace how nitrogen and phosphorus move through freshwater systems, how they are transformed in the process. To identify important ecological factors that influence movement and transformation of
nitrogen and phosphorus. Why are N and P important? N and P commonly the nutrients in greatest demand by plants and heterotrophic microbes relative to supply (i.e., limiting resources). N commonly limiting in terrestrial systems, estuaries, and oceans.
P commonly limiting in freshwater systems. The problem with N Nitrogen is an essential part of amino and nucleic acids N is abundant on Earth (78% of atmosphere) Only 2% available to organisms as reactive N (bonded to C, O, or H)
The rest is unreactive N (triple-bonded N2) N2 io at fix n
The Nitrogen Cycle N2 io at fix
n Nitrogen Fixation Cyanobacteria with Heterocysts N2
io at fix n Nitrogen Mineralization, Immobilization,
and Uptake io at fix Nitrification
N2 n Nitrification Requires high O2 Also very sensitive to pH rates severely reduced at pH < 5.0 When O2 or pH too low, then stops at intermediate
forms: NO2- (nitrite) and N2O (nitrous oxide) In freshwater systems, interested in nitrification because N needs to be in oxidized forms (NO3and NO2-) to partake in denitrification Nitrification at high pH io at
Lower metalimnion Sewage treatment plants Who is doing the work and what are they working with? N fixation: Cyanobacteria and terrestrial N-fixers
Light + N2 NH4+ immobilization and uptake: Microbes and plants NH4+, Light or No light, O2 or CO2 Nitrification: Chemoautotrophic microbes NH4+, O2, moderate pH Denitrification:
Anaerobic bacteria and fungi NO3- (NO2- or N2O), Carbon, low O2 Nitrogen Distribution in Lakes Nitrogen in Rivers:
Effects of surrounding forests Leaky Retentive Whole-Watershed Manipulations: Control vs. Cut and Leave
WholeWatershed Results Similar results from fire, but if build-up of charcoal in soil, then sorption of NO3-. Can also have formation of NH4+ in
atmosphere due to heat (energy from fire), then direct deposition. The 1998 Ice Storm Post-Storm N Spike Ice storm
~ Deforestation Ice storm ~ Deposition In-Stream Retention of N
Nitrogen and Humans Nitrogen and Humans Natural N-fixation: N2 SOLAR ENERGY NH4+ Industrial N-fixation via Haber-Bosh process N2(g) + 3H2(g) HEAT 2NH3(g)
Combustion of fossil fuels NOx Nitrogen and Acid Rain H2SO4 HNO3
Delivery of N to Coastal Ecosystems Eutrophication of Coastal Ecosystems The Dead Zone
The problem with P P is a major cellular component, but occurs at VERY low levels in freshwater systems P often limits primary production in freshwater systems Phosphorus in freshwater systems
Phosphate PO43- Phosphorus in freshwater systems PO43- Organic P Bound in living
or decomposing material Phosphorus in freshwater systems PO43- Organic P Particulate P
Stuck to particles, especially metaloxides (e.g., FeOOH+) Also in sedimenting organic particles Carried to sediments Phosphorus in freshwater systems PO43- Organic P
Dissolved P Particulate P aka, SRP Released via decomposition by anaerobic bacteria in sediment Also some decomp.
in water column Sources of P in freshwater systems Runoff from land Direct deposition from atmosphere Pollution: wastewater, detergents, fertilizers, animal excretion
Cycling of P in freshwater systems PO43- Biological Immobilization PO43-
Cycling of P in freshwater systems PO43o talMe e xid .g., s (e FeO
Biological Immobilization +) OH Organic particles
Sedimentation Cycling of P in freshwater systems PO43o talMe e xid
.g., s (e FeO Biological Immobilization +)
OH Organic particles Sedimentation HOT SPOT
Controls on P-exchange between sediment and water Decomposition by anaerobic bacteria and turbulence at mud-water interface. Controls on P-exchange between sediment and water
Decomposition and turbulence at mudwater interface Redox conditions within the sediment > Oxidized zones = retention by sorption > Anoxic zones = release by reduction Controls on P-exchange between sediment and water Decomposition and turbulence at mudwater interface
Redox conditions within the sediment Water acidity > As pH increases, PO43- released Phosphorus Distribution in Lakes Internal Loading of P Change in internal conditions of lake
cause massive release of P in sediments Mixing of sediment Increased pH Whole-lake anoxia Eutrophication of Lakes P in rivers
Pulse with high runoff or early stages of snowmelt Generally see higher P levels in rivers and streams than in lakes because access to biota limited by flow dynamics The Nutrient Spiraling Model How far downstream does the average
atom of [YOUR FAVORITE NUTRIENT] travel before being taken up by the biota? The Nutrient Spiraling Model P Labeled Nutrient
3(e.g., PO4 or NO3 ) + Estimating S Concentration Inert Tracer
(e.g., Br or Cl) S Low = Retentive S High = Leaky Tracer Nutrient Downstream
Chapter 4. Symmetry and its Applications. Symmetry = do something to a molecule and have it look the same. ... IR active translate as x, y, z functions. Raman active translate as xy, xz, yz, z2, etc. functions. Vibrational Analysis...
Focus for today. EU5: The Republican ideal in the U.S. manifests in the structure and operation of the legislative branch. 5.A.2: Compare the Senate and House of Representatives in terms of how constituencies, lawmaking authority, and chamber rules and roles...
Change of Major Fall 2010 THE Working Group: Mary Pedersen, CAFES Debra Valencia-Laver, CLA Penny Bennett, CLA Dan Walsh, CENG Fred DePiero, CENG Stacey Breitenbach, CENG Dane Jones, CSM Dick Zweifel, CAED Ellen Notermann, CAED Amy Swanson, OCOB Melinda Rojo,...
ROCK SNOT Russ Rhodes Department of Biology Missouri State University Springfield, Missouri I would like to acknowledge Mr. Robert Britzke from Eureka Springs, Arkansas for pointing out the presence of Didymosphenia geminata in the tail race area of Beaver.
Morgan Kaufmann Publishers. August 23, 2017. Chapter 1 — Computer Abstractions and Technology. Chapter 1 — Computer Abstractions and Technology — 13. Integrated Circuit Cost. Nonlinear relation to area and defect rate. Wafer cost and area are fixed.
When the electron changes its configuration, energy is emitted in the form of a single photon of energy If the atom has only discrete energy levels, then there should be a minimum amount of energy that can be added to...
Ready to download the document? Go ahead and hit continue!