Aquatic and Wetland Plants Lecture

Why are aquatic ecosystems important?

habitat, refugia and food for aquatic organisms

Anthropocentric recreation

Environmental services: water filtration, algal control, erosion control

Economically important aquatic plants: rice, invasive aquatic plants

Definition of aquatic plants

Grow in/near water, evolved to exhibit various forms. Few are fully aquatic

Ephemeral aquatic areas

Are wet for only a portion of the year

How do we define aquatic community boundaries?

By using aquatic plants

Four types of aquatic plants

submerged, floating, emergent, shoreline

Submerged plants

Underwater for full life cycle, roots located in submerged soil at the bottom of water

Floating plants

Plants float on water’s surface, roots may float or be submerged in soil

Emerging plants

Plants with a large portion of their architecture elevated above water’s surface. Roots located in submerged soil

Shoreline plants

Found near the edge of a body of water. Tolerate periodic flooding, but their roots are not fully/continuously submerged

Label structures A-E with proper plant architecture terminology.

A. Leaf axil: point at which the leaf connects to stem or branch
B. Internode: area between nodes
C. Node: area of the stem where buds develop and form into stems/branches
D. Axillary bud
E. Leaf

Label structures A-J with proper leaf components.

A. Veins
B. Adaxial surface (top, facing stem)
C. Abaxial surface (bottom, away from stem)
D. Margin (edge of leaf)
E. Apex (tip of leaf)
F. Blade
G. Pulvinus (joint-like thickening at base of leaf/leaflet, helps move the leaf)
H. Stipules
I. Stem
J. Bud

What shape is this leaf?

Acicular: needle shaped

What shape is this leaf?

Falcate: sickle-shaped

What shape is this leaf?

Acuminate: long with tapering point at tip

What shape is this leaf?

Ovate: egg-shaped and wide at base

What shape is this leaf?

Lanceolate: pointed at base

What shape is this leaf?

Cordate: heart-shaped

What shape is this leaf?

Lobed: indented margins

What shape is this leaf?

Deltoid: triangular

What shape is this leaf?

Palmate: hand-shaped

What shape is this leaf?

Elliptic: oval-shaped with little to no point at tip

Label structures A-H with proper leaf margin terminology.

(hint: A & C are asking for the term for these sides)

A. Apical side

B. Tooth apex

C. Basal side

D. Entire: leaf margin is smooth

E. Crenate: leaf margin is wavy

F: Dentate: teeth on leaf margin at 90 degree angles

G: Serrate: teeth on leaf margin LESS than 90 degree angles

H: Doubly serrate: serrate with small sub-teeth

What type of venation does this leaf display?

parallel: veins run parallel to one another (monocots)

What type of venation does this leaf display?

arcuate (think that the veins are ARCING)

- veins arch to come into contact (or nearly) at the leaf apex

What type of venation does this leaf display?

dichotomous: veins branching in pairs, may or may not end in teeth

What type of venation does this leaf display?

dichotomous: veins branching in pairs, may or may not end in teeth

What type of leaf arrangement does this plant display?

alternate: 1 leaf per node

What type of leaf arrangement does this plant display?

opposite: 2 leaves per node opposite from one another on stem

What type of leaf arrangement does this plant display?

whorled: 3 or more leaves per node

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.)

Simple: single blade connected to a stem

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.)

Trifoliate: single blade with three lobes

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.) and label structures A-D.

Pinnately-compound: each leaf has multiple leaflets

A. Rachis (area of petiole between leaflets)

B. Petiolule (where leaflet meets rachis)

C. Petiole

D. Terminal leaflet

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.) and label structure A.

Pinnately-compound: each leaf has multiple leaflets

A. Leaflet

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.)

Palmately-compound leaf: leaflets arranged to resemble a hand

Bipinnately-compound: two levels of division

A. Leaflet

B. Petiolule (where leaflet meets rachis)

C. Rachis (think baby stem on compound leaves)

D. Petiole

Explain the type of leaf complexity this leaf possesses (simple, compound, etc.) and label structures A-D.

Peltate leaves

Petiole attached to the abaxial (lower) leaf surface (umbrella shaped)

Petiolate leaves

attached to the stem by a petiole (leaf stalk)

Sheathing leaves

with the lower portion of a grass leaf enveloping, but not fused to the culm, except at a node

Perfoliate leaves

With basal lobes completely surrounding the stem, and fused (connate) around the stem

Name flower structure A and its component parts A1-A4

A: stamen

A1: connective

A2: anther

A3: microsporangium

A4: filament

Name flower structure B and its component parts B1-B5

B: perianth

B1: floral axis

B2: pedical

B3: nectary

B4: sepal/calyx

B5: petal/corolla

Name flower structure C and its component parts C1-C4

C: pistil

C1: stigmaa

C2: style

C3: ovary

C4: ovules (within ovary)

wetland indicator status OBL

99% occurrence in wetland

wetland indicator status FACW

67-99% occurrence in wetlands

wetland indicator status FAC

34-66% occurrence in wetland

wetland indicator status FACU

1-33% occurrence in wetland

wetland indicator status UPL

<1% occurrence in wetlands

Factors that make wetlands differ

salinity, temperature, depth, proximity to neighboring water bodies, soil types, aquatic plant community

Palustrine

inland, non-tidal wetland with less than .5 ppm marine salt

Riparian

wetlands adjacent to rivers and streams

Estuarine

brackish water with one or more rivers/streams meeting the sea: transition from river to maritime

Marine

oceanic/sea water

Ramsar convention on wetlands

includes areas of restored and man-made/impacted wetlands,. 10 categories accepted in the literature

Peatland (Palustrine)

Unique soils produced by waterlogged conditions that prevent plants from decomposing: organic matter exceeds its decomposition rate

Peatlands function

Cover about 2.84% of earth’s terrestrial surface, store and sequester and exceptional amount of carbon. When drained, carbon oxidizes to CO2. Overtime proper hydrology cannot be restored without soil amendments

Bogs

(peatlands) peat-accumulating wetlands that are hydrologically isolated from groundwater or surface flows, ph<6.

Bogs vegetation

Sphagnum mosses mixed with conifers or Ericaceae shrubs

Fens

Peatlands connected to ground/surface water, ph 6-8.

Fen vegetation

graminoids (grasses and sedges), various shrubs/trees

Pocosin

Temperate peat wetlands with deep, acidic sandy peat soils (Southeast VA, NC, SC) in higher elevations

Pocosin vegetation

woody evergreens

Seagrass beds

marine herbaceous non-peatland: near-shore aquatic habitats in coastal marine ecosystems

Seagrass bed vegetation

herbaceous aquatic angiosperms (Alismatales)

Salt marshes

estuarine herbaceous non-peatland: tidal zones of coastal ecosystems

Salt marsh vegetation

salt tolerant grasses (halophytes)

Littoral zone wetlands

lacustrine herbaceous non-peatland: margins of lake ecosystems, water no deeper than 2m, water can be fresh or brackish

Littoral zone vegetation

mixture of herbaceous plants

Marshes

palustrine herbaceous non-peatland:broad category of shallow freshwater wetlands

Marsh vegetation

variety of herbaceous species

wet meadow

palustrine herbaceous non-peatland: freshwater-shallower depth than marshes or short duration flood period

wet meadow vegetation

greater diversity than marshes, lots of graminoids

mangrove swamps

marine woody non-peatland: marine coastal wetlands dominated by mangrove trees or shrubs: tropical and subtropical regions. Exhibit ecological zonation/taxonomic differentiation with different depths

swamps

palustrine woody non-peatland: wetlands dominated by trees with occasional shrubs, fresh or marine waters

Wetlands present in KY

Swamps (Cypress/Tupelo swamps in Western KY), Bogs/seeps (high elevation Eastern KY and lower elevations in coastal plain region), marshes (spanning the state, common in low-lying areas), wet meadows (very degraded due to agriculture)

Four factors determining if a location can support a wetland ecosystem

water depth, duration, frequency, chemical composition

Water balance equation

ΔS = Pn ± Qo ± QS/G − ET (water storage equals net precipitation minus flow in/out of wetlands minus evapotranspiration)

Label water sources in and out of wetland A-G

A: Qs/g in

B: Qo in

C: Pn

D : evaporation

E: ET

F:Qo out

G: Qs/g out

Pn

net precipitation: precip can be intercepted by plants

Qo

overland surface flow into and out of wetland, eg runoff

Qs/g

subsurface/groundwater flow in/out of wetland

Ways to measure water input/output

Rain gauge: tipping bucket gauges limit evaporation/splash

Ways to measure interception

Measure precipitation above/below canopy to get net precipitation. For stemflow, collars may be placed around a tree trunk. For fall through, rain gauges beneath the canopy

How to measure streamflow

Volume of water passing a selected point. Velocity will differ based on regions of the stream velocity of water and cross/sectional area at given point. Can use a weir or a flue, control water levels by calculating streamflow rates, but must be installed via stream manipulation

How to measure runoff

For true estimates collection troughs were installed on the base of a slope where water will accumulate so volume can be measure. Now can use electronic loggers to continuously measure water pressure/depth

How to measure soil/groundwater flow

Darcy’s law, soil cores, wells, pizeometer, lysimeter

Darcy’s law

Q = Ksat A*(Sh/Sx), hydraulic conductivity of soil times cross section of subsurface layer times hydraulic gradient across layer of interest

How to measure evapotranspiration

Water potential= free energy of a sample of water relative to a pure water and tendency of that water to move to a gradient. Becoming more negative with increasing mineral ions and sugar. Water will move from high to low potential. Water potentials approx 0 mPA for freshwater wetlands and -2.7 mPA for saltwater systems

Factors that may impact evapotranspiration

solar radiation, water vapor deficit, air temperature, wind speed in the tree canopy

Plant evolution

first from an aquatic environment then onto land: gained vascular systems, stomata and a cuticle

Photosynthetic components that may be obstructed in aquatic environments

Light: limited by mineral and organic matter which can absorb, reflect and scatter light as it passes through water. Carbon access: CO2 is soluble in water and gets into water via diffusion, some fully submerged plants may use bicarbonate from rocks/soils

components of respiration that may be obstructed in aquatic environments

carbohydrate produced, oxygen, water’s ability to hold oxygen deals with atmosphere and water pressure/water temp

Patterns of O2 availability

Daily fluctuations in DO2 because of photosynthesis in water column: consumption of O2 by aerobic microbial metabolism; Release of O2 into soil by plants; inputs of rainfall/overland surface flow into wetland; exposure of soil/sediment during drought

Carlton and Wetzel (1988) takeaways

Microbes rapidly consume oxygen: plant roots struggle to acquire O2 in deep soil, especially if no photosynthesis

Hypoxia

<2.5 mg/l in aqueous environments

Factors inducing hypoxia

Decomp of organic matter consumes O2: without enough O2, microbial community shifts from being aerobic to anaerobic

Hypoxia and denitrification

Microbes produce nitrogen from nitrate, use manganese, then iron, then sulfate, then start to generate methane: usable nitrogen leaves wetland and goes into atmosphere: reduced forms of Mn, Fe and S harm plants

How do plants deal with hypoxia?

Temporarily switch to anaerobic respiration: burn sugars produced during photosynthesis: lactic acid/ethanol are byproducts. Helps maintain energy production

Aerenchyma

Internal air passageways, allows for O2 diffusion within plants, occur predominantly in roots. Production enhanced in response to flooding. Allows O2 to diffuse into roots and ethylene out of roots

Lenticels

In woody plants: small area where bark is interrupted allowing for gas exchange

Pneumatophores

Specialized root structure growing out of water surface for aeration, common in mangroves and bald cypresses