Wetlands Exam 1

whet are wetlands?

transitional systems between terrestrial and aquatic ecosystems at surface or below roots

what are the 3 unique features of wetlands?

hydrology, soils, and vegetation

hydrophyles

water-adapted plants

wetlands can function as…

sources, sinks, or transformers of carbon and nutrients

vernal pools

wet meadows that are flooded in the spring

climates without wetlands

dry areas with little rainfall will not have wetlands, climate determines wetlands; colder temperatures mitigate evapotranspiration losses

high plant density

keeps water from moving around as much

scientific definition of wetlands

facilitates classification, inventory and research

regulatory definition of wetlands

can be legally binding, must be very specific

legal definition of wetlands

jurisdictional wetlands, wetlands regulated under specific terms

wetland history

highly neglected and altered ecosystem, indigenous populations coexisted w/ wetlands

western civilizations and wetlands

westerners typically saw wetalnds as a problem

post 1970s wetlands

greater attention to wetlands after hunters saw duck populations decline

Ramsar

only global treaty for wetland protection

sediment

wetlands can handle excess sediment

water flow

wetlands can supply groundwater flow and contribute to stream flow, act as a temporary reservoir

coastal

protect coast from storms by buffering energy

where are wetlands most commonly found

in boreal and temperate regions near the equator with lots of rainfall

boreal wetlands

accumulate sediment, cold air keeps it wet

temperate wetlands

lots of wetlands in temperate zones are removed for human expansion because it is too cold to inhabit boreal areas, over ½ of wetlands are gone

coastal wetlands

• near the coasts, salinity approaches 35 parts per thousand, freshwater closer to 0

• buffers hurricanes and coastal storms

• flora and fauna adapted to higher salinity

mangroves

• replace tidal salt marsh in subtropical and tropical zones

• halophytic vegetation, exxposed roots allow oxygen exchange

head of tide

where inland extent of tidal influence ends, gradient of salt decreases

inland wetlands

non-tidal marshes with diverse characteristics, shallow water regime, and shallow peat reserve

prairie potholes

shallow marsh-like ponds found in the Dakotas and central Canadian provinces, made from glaciers pre-agriculture

peatlands

• contain deep organic peat deposits

• very spongy, very bouncy because its all organic matter

bog

peatland that does not get groundwater because of its higher elevation, has acidic and anoxic conditions

fen

very basic conditions with groundwater

pocosin

peat-accumulating non riparian “swamp on a hill”, water mostly from precipitation

swamps

• freshwater forested wetlands of southeast US

• characteristic cypress stabilizes in soggy environment by flaring trunk

• dominated by trees and shrubs

• alluvial - flooded by streams & rivers

riparian ecosystems

• wetlands along margins of rivers, creeks, and lakes

• most dynamic and productive, lots of nutrient flux from runoff moving nutrients

• considerable water fluctuations, drier than swamps

• found along most large rivers and lakes

palustrine

tidal and non tidal freshwater wetlands dominated by shrubs

riverine

freshwater rivers, non-persistent vegetated wetlands

lacustrine

lakes and reservoirs, including non-persistant vegetated wetlands

estuarine

estuaries

marine

open ocean and associated wetlands

tocoine

isolated wetlands, headwater outflow not subject to overflow because of eluviation

lentic

associated with lakes

lotic

associated mostly with streams

marine salinity

<30ppt

polyholine estuary salinity

<18ppt

mesohaline salinity

<5 ppt

oligohaline salinity

< .5 ppt

hydrology

movement of water through a landscape

climate controls

wetland in wet & cool climates vs. hot & dry, hotter = more evaporation and less wetland

basin geomorphology

depressional locations can have wetlands

sea level rising

leads to salt watr coming into freshwater wetlands, kills vegetation

wetland soils

water fills up gaps in soil, no oxygen makes anoxic conditions unsuitable for decomposition → organic matter accumulation

physiochemical environment

determined by hydrology, determines flora & fauna

beavers

keystone species that alters the movement of water by building dams, nature’s engineers

hydroperiod

“heartbeat” of wetland, sum of inflows & outflows

flood duration

amount of time a wetland is in standing water

flood frequency

number of times a wetland is flooded inna given period

water level fluctuations can occur…

seasonally, daily, unpredictably

dynamic wetland

have changing water regimes

soil

layer of loose material above rock, forms over thousands of years by weathering and the breaking down of bedrock

soil forming factors

climate, topography, parent material, plants and animals, time

O horizon

organic matter

A horizon

where mineral soil starts

E horizon

organic matter not yet on this layer

B horizon

leached material accumulates

C horizon

closest to bedorck, least weathered

leaching

eluviation in A and E horizons

accumulation

illuviation in B horizon

histosols

thick organic matter layer, wetland soil, prairie biomass accumulates

mollisols

best soil for crops

vertisols

expand and contract, not best for crops, rainy climate

andisols

volcanic soil

aridisol

dry region

entisol

youngest soil

gellisol

permafrost, very cold climate

mineral matter %

45%

organic matter %

5%

air %

20-30%

water %

20-30%

dark soils

organic matter

reddish-brown soil

iron oxides

whitish soil

carbonates, e.g. calcites

grey or greenish soils

reduced iron oxides

black

manganese oxides

green soils

glauconites

Munsell system

uses hue, chroma, and value to characterize a soil’s color, used in delineation and soil analysis

sand

.05-2mm, gritty and mostly quartz

silt

.002-.05mm, flowy, soft, smooth, quartz dominant

clay

>.002mm, sticky, slick

particle size

as a particle gets smaller, surface area increases

soil bulk density

dry weight of soil/volume = w/V

density of water

1 mg/m³

soil porosity

1-(bulk density/particle density)-100

mineral soils

12-18% organic carbon, or greater than 20-35% organic matter

organic soil

greater than 20% to 25% organic matter, greater than 12 to 18% organic carbon, acidic

oxic conditions

high or moderate O₂

anoxic conditions

low or negligible O₂

hypoxic conditions

less than 2mg/L

oxygen depletion

occurs when decomposition consumes all oxygen, or when soil moisture restricts oxygen movement

wetland soil drainage

poorly drained and very poorly drained

oxidation

loss of electrons, occurs alongside reduction

reduction

gain of electrons, occurs alongside oxidation

example of redox reaction

organic matter decomposition — electron acceptor O₂ gains electrons from organic matter decomposing, higher O₂ levels means for faster decomposition, providing more energy, oxidizing carbon

redox potential

metric of the tendency of a substance to lose or gain electrons