biogeochem: Phosphorous cycle

what is the biggest reservoir for P

sediments

what is the residence time for P in sediments

super slow, 1.82×10⁸

describe the phosphorus cycle

weathering (and mining) pulls P from sediments. goes to crops, internally cycles with plants and soils, runs off into water ways, cycles through ocean waters, gets buried in sediments to be brought up again

how as the P cycle been altered by humans

through mining and fertilizer. 4x increase!

Is P easily available, why or why not?

P is easily immobilized by chemical reactions. Binding removes P from bio-available pools. Although total P in soils can be large, only a small fraction is available to biota. Microbes are important in transforming organic P to inorganic and mobilizing chemically fixed P to more bio-available forms

what binds to materials and depends on what

Ca, Mg, Fe, Al

apatite, hydroxylapatite, fluorapatite

chemical P fixation is pH-dependent

how is P exported from terrestrial ecosystems

runoff

how is P returned to terrestrial ecosystems

new ways - guano is one

does P have a gaseous phase?

No significant gaseous phase

how is aquatic productivity limited by P

P is absorbed by plants, algae, and some bacteria. assimilatory reactions, not dissimilatory

what is an example of too much P

HABs in Lake Erie

What action was taken to address HABs in Lake Erie

• binational agreement to reduce P by 40%

• 2012 Great Lakes Water Quality Agreement

what did Ohio do to address high P

• fertilizer and manure ban

• dredging limits

• wastewater treatment rules

what is challenging about reducing P

Can regulate waste water treatment, but CANT regulation nonpoint sources so you have to get creative and try to regulate fertilizer composition and application

Michigan Domestic Action Plan

• Michigan Department of Agriculture and Rural Development (MDARD)

  • Supports conservation practice implementation with additional state funding for the Western Lake Erie Basin

  • Formally tracks progress using the Great Lakes Watershed Management System

• Michigan Department of Environment, Great Lakes, and Energy (EGLE)

  • Administers Point Source Permit Program

  • Monitors tributary nutrient loads

  • Supports watershed management planning and implementation

• Michigan Department of Natural Resources (DNR)

  • Assesses and monitors fish and wildlife populations and habitats

  • Protects and restores wetlands

Priority watersheds: River Raisin and Upper Maumee River and had 4 key wwtp permit limited