Wetlands

• prof ES1 224 9-12 wednesday
• http://uwwrc.net/

marks

• final 40%
• wetland evaluation 35%
• midterm 25%

• wetland: land saturated during most of the year -> soil poor in oxygen -> supports specialized biotic communities
  • canadian def: saturated -> promote wetland/aquatic processes as indicated by poorly-drained soils, hydrophytic vegetation, various biota adapted to wet environment
• 2 broad categories in Canada: 75% organic (peat) soils (>=40cm deep), and 25% mineral soils
• 1/3 of Canada's wetlands are frozen
• Sphagnaceae > Sphagnum
• carnivorous plants only in wetlands

• argh... type up notes

wetland classification

• basin classification
  • bedrock eg karst, volcanic, fault
  • unconsolidated sediments eg glacial, river-activity, shoreline processes, isostatic uplift, wind-formed, biotic (eg beaver)
• water source classification (-genous = water)
  • ombrogenous: mostly from atmosphere
  • terrigeneous: mostly from surrounding land (or groundwater)
  • soligenous: from surface
  • littogenous: from literal (coastal) zone eg marine, riverin, estuarian, ?
  • water flow can be vertically (up and down), horizontally both ways, and horizontally in one direction
• geochemical classification
  • freshwater
    • oligotrophic: low pH, low dissolved minerals
    • ombrotrophic: same as oligatrophic but more extreme; input only from atmosphere
    • minerotrophic: high pH, high dissolved minerals, neutral and alkaline
      • in descending solutes: calcareous, rich, intermediate, poor
  • saltwater: inland, sea, salt spray, estuary
• sediment/strata classification
• structure classification
  • trees: greater or less than 15m tall
  • shrubs: 1.5m and 0.5m classification boundaries
  • herbaceous (roots location... (?))
  • bryophytes
• floristic classification

canadian classification

• 2 major divisions
  • mineral: insignificant organic accumulation, modified by water control structures (?)
  • organic (aka peat or peatland): at least 40cm organics
• classification is Class > Form > Type
• classes
  • swamp
    • peatland/mineral
    • water table at/just below surface
    • minerotrophic
    • soil: highly decomposted woody peat
    • trees, tall shrub (thicket) cover
    • strong surface and /or groundwater input = minerogenous -> high runoff, ET high (trees) maybe
  • bog
    • peatland
    • water table at or just below surface
    • ombrotrophic
    • surfaced raised or level with surrounding land
    • soil: semi-decomposed sphagnum with woody remains
    • trees, shrubs, or treeless
    • not well served by streams; ET dominates loss
  • fen
    • mostly peatland
    • water table at or very close to surface
    • minerotrophic mostly
    • surface level with the water table
    • soil: decomposed sedge or brown moss peat
    • graminoid, shrub cover
    • ET is high (basin shape, plants); runoff high when water above surface, but decreases a lot when water table is low
  • marsh
    • mineral (mostly)
    • shallow surface water which fluctuates
    • minerotrophic or eutrophic
    • thin organic accumulation
    • rushes, reeds, grasses, sedges, with emergent and floating aquatic herbaceous species
  • shallow water
    • standing/flowing water (<2m deep)
    • limnetic, organic material
    • floating leaved, submerged aquatic vegetation
  • marsh AND shallow water
  • high ET, mostly from open water; groundwater recharge could be significant; maybe no runoff

• HGM: hydrogeomorphic, the method used in the US

water stuff

• something about hydroperiods...
• dynamic storage (water volume that changes daily/seasonally) vs static storage (water in soil, doesn't change much annually)
• "flood control": depends on wetland type (relation to water table), runoff can dissipate or *not*

geochem stuff

• anaerobic -> biocem unique to reducint conditions
  • although oxygen-rich above
• redox is sorta "oxygen vs hydrogen"
• typical thermodynamic sequence
  • oxygen + hydrogen ions + electrons <-> water (uh...?)
  • denitrification (disappearance of NO₃^-)
  • creation of manganous Mn²⁺
  • iron reduction -> ferrous Fe²⁺
  • sulphate reduction -> H₂S
  • methanogenesis -> CH₄

old midterm

• /10 - define 5/8 terms (2 marks each = make 2 points each, can draw)
  • anoxia
    • very low oxygen (okay, need more...)
  • hydroperiod
    • ? graph of water volume vs time for a particular wetland. looks different for types of wetlands and even individuals of the same type, shows cycles etc.
  • swamp (answer copied from above)
    • peatland/mineral
    • water table at/just below surface
    • minerotrophic
    • soil: highly decomposted woody peat
    • trees, tall shrub (thicket) cover
    • string surface and /or groundwater input = minerogenous -> high runoff, ET high (trees) maybe
  • ombrotrophic indicator
    • ombrotrophic: low pH, low dissolved minerals (extreme); input only from atmosphere; so indicator is... ?
  • redox
    • hmn, what it really means, or how we learned it? ...
  • groundwater discharge
  • ombrogeny
    • wetland's water comes mostly from the atmosphere (rain, snow, fog), rather than ground or surface water (is that enough for 2pts?)
  • marl
    • wp CaCO₃-rich mud w/ clay
• /6 - 3 points on why wetland science deserves to be a distinct science
• /10 give water budget for 2 contrasting wetland classes (identified, with reasons)
• /10 describe typical thermodynamic reduction sequence for inorganics in wetland (assuming major stuff present)
  • answer copied from above
  • oxygen + hydrogen ions + electrons <-> water (uh...?)
  • denitrification (disappearance of NO₃^-)
  • creation of manganous Mn²⁺
  • iron reduction -> ferrous Fe²⁺
  • sulphate reduction -> H₂S
  • methanogenesis -> CH₄
• /4 what's the point of wetlands classification
  • each type has different biota, hydrology, etc. and classification gives us greater knowledge allowing us to treat them as such. for example if endangered species X lives in wetland type Y, we know that we need to preserve Y, as opposed to any particular wetland. so classification is useful for legislation, conservation, construction, research, etc.
• =/40 ?

Adaptations to Anoxia (low O₂)

Structural

• aerenchyma: gas-filled lacunae system, held together with porous aerenchyma
• aerenchyma is 10-12% of root-cross section for flood-intolerant plants, 50-60% of flood-tolerant plants
• forms via cell wall separation, collapse of cells or enlargement of separations
• aerenchyma is proportional to reducing conditions
• it decreases resistance to flow by O₂, allows CO₂, etc. to escape
• allows gas to be stored (50% of leaf volume in cattails)
• roots
• adventitious roots: new roots that form laterally from main stem within days of flooding
• usually form in O₂-rich water and less root biomass needs O₂
• done via hormone auxin
• shallow rooting: woody/herbaceous plants have shallower roots than in terrestrial environments
• gives roots access to O₂, nitrate
• pneumatophores: modified erect roots that grow up from roots (“knees”)
• height corresponds to maximum height of water
• most O₂ used by pneumatophores, little is transported to the roots
• releases 3-22% more O₂ than equivalent trunk area
• prop roots/deep roots: develop from lower part of stems/branches and grow out towards the substrate
• covered with lenticels that allow O₂ to diffuse
• help anchor the plant
• stems
• rapid underwater shoot extension via hormone ethylene
• brings plants near (or to) the surface -> light, O₂, CO₂
• hypertrophy swelling of stem base in response to flooding in herbaceous/woody plants since accelerated cell expansion since separation/rupture
• increases porosity, aeration
• eg buttressing
• stem buoyancy to take up O₂, CO₂, especially for submerged plants
• Gas Transport Mechanism
• passive molecular diffusion
• most important!
• O₂ about the same (21%) in the atmosphere as in the aerial parts of the plant, vs. 4% in the rhizomes
• pressurized ventilation
• helps diffusion
• air goes into stomata of young lives (smaller stomata -> higher gas concentration) and goes down the stems to the rhizomes then up stems and exists through old leaves
• underwater gas exchange
• gas exchange between the plants and water
• e.g. pneumatophores of mangroves
• venturi-induced convection
• based on wind speed gradient
• tall stems exposed to fast wind (lower air pressure)
• air pulled in through low stems to the rhizomes then out the tall stems
• in moderate wind, 80% or more O₂ (theoretical)
• radial O₂ loss (diffusion, etc.)
• submerged plants have less aerenchyma and radial O₂ loss than emergents
• oxidizes toxic substances in rhizosphere
• forms plague on roots (e.g. iron)
• development of carbohydrate storage structures
• flood-intolerant plants can handle 3 days
• tolerant ones 4-90 days

• plants need more glucose (usually stored in rhizomes) when anaerobic
• plants with carbohydrates (fermenting makes it glucose) survive flooding
• more carbohydrates stored more in spring

Metabolic processes

• can adjust in minutes to hours (to anaerobic) (based on lab experiments)

Salt-Water adaptations (halophytes (glycophytes don’t like salt))

• water acquisition
• water potential = free energy content of water / volume
• higher in soil water than within plant if non-saline
• salt decreases water potential
• osmotic adjustment (osmoregulation) produces compatible solutes
• salt avoidance
• exclude from roots, e.g. by Casparian bands
• some can recognize Na, Cl, and prevent uptake
• secrete via salt glands on leaves
• shed plant parts with salt in them
• succulents
• increasing cell size (thick leaves/shoots, few leaves) dilutes internal salt concentration
• can close stomata to keep water

Adaptations to Limited Nutrients

• mycorrhizal associations
• symbiotic fungi (with plants’ roots)
• plant captures more water, phosphorus, etc.
• fungi get carbohydrates from roots
• endomycorrhizal (VAM) vs. ectomycorrhizal
• nitrogen fixation
• N₂ made available to plants
• usually via bacteria (in nodules) which get their energy from plants
• in legumes, alder, sweet gale, etc.
• N-fixing cyanobacteria in mangroves
• carnivory
• zooplankton to insects, even frogs and birds
• mostly tropical and subtropical
• 65% of the 500 spp. are in Australia
• types
• pitfall e.g. pitcher plant
• lobster pot
• passive adhesive
• active adhesive
• bladder
• snap trap
• evergreen leaves
• common e.g. heath shrubs
• no need to re-grow leaves

Adaptations to Submergence

• limited light
• ribbony leaves (high surface-to-volume ratio): light and gas diffusion
• greater concentration of chlorophyll in submergents/emergents
• low CO₂
• more aerenchyma to increase buoyancy
• HCO₃ for carbon
• water fluctuations
• heterophylly: different leaves so can handle wet and dry

Wetland Creation/Restoration

• restoration: active (needs people to fix) vs. passive (duh)
• human-induced vs. artificial (requires continuous fixing)
• enhancement: increase some stuff, may decrease others
• mitigation: creation/restoration/enhancement
• mitigation banking: new wetland to “make up” for ones that one’ll get rid of (yay U.S. of A.)
• Canada’s lost up to 70% of wetlands in key areas
• duck habitat
• ideal is half each of open water and vegetation
• nutrients (P, N)
• 0.5-1 metres deep

• ecological engineering ? environmental engineering
• ecological engineering = ecotechnology
• design of human society with natural environment to help both
• why?
• pollution fix e.g. sludge recycling
• reduce/solve problem e.g. aquaculture
• disturbance recovery e.g. surface mine
• enhanced to solve a problem e.g. biomanipulation
• self-design, sustainable
• habitat
• water/wastewater fix
• flood control
• treating wastewater
• pond systems: stabilization, liners, forced aeration
• floating aquatic plants: duckweed, water hyacinth
• wetland types
• natural: marsh, shallow water
• man-made: surface flow, subsurface flow, floating plant systems (argh see my drawings)
• bureaucracy stuff
• performance criteria
• maintenance, monitoring
• UV kills E. coli
• plants encourage bacteria etc.
• expect non-plug flow and seasonal variation
• mosquitoes
• flood water vs. permanent water mosquitoes

Wetland Values

• wetland values: services/commodities to humans
• population: waterfowl, birds, fur-bearers, trees, rare species
• ecosystem: flood control, aquifer protection/recharge, water quality, aesthetics
• regional/global: carbon and sulphur cycles
• wetland functions/processes
• ecological/environmental attributes
• socioeconomic functions
• wetland benefits: values society puts on wetland processes, socioeconomic functions/benefits
• conservation approaches
• creation, restoration, enhancement
• secure/protect
• Canadian government had said they’d protect 12% of landscape
• secured areas: government or private-owned for conservation
• national parks, etc.
• designate important sites
• Ramsar – 36 sites in Canada
• international biosphere reserves
• national, provincial sites
• ANSI: areas of natural or scientific interest
• development of policies/legislation
• federal policy on wetland conservation 1990
• most provinces have non-regulatory (consultative) processes
• policy, implementation, cooperative approach (huh?)
• North American Waterfowl Management Plan
• creation, restoration
• Ducks Unlimited
• industry/private sector
• local initiatives
• Canadian milestones
• 1979 etc classification system
• 1987 Ramsar
• 1990 national policy
• etc..