Streams and Wetlands (and intro to Aquaculture?)

Streams and Wetlands (and intro to Aquaculture?)

August 28th, 2007

LAKES: Nutrient cycling and algal blooms

Is this lake eutrophic or oligotrophic?

Streams and Rivers

Streams and Rivers

5th order

4th order

3rd order

2nd order

1st order (headwaters

)

How do large and small streams differ?

• Low stream order (i.e., 1st or 2nd order)• Small, narrow, shallow• Steep, fast-flowing rocky bottom• Detritivore community breaks down litter

• High stream order (i.e., 4th or 5th order)• Big, wide, deep• Shallow slope, slow flowing• Processed litter comes from upstream

Stream/River Characteristics

• Streamflow is determined by:– Relief– Volume of Input– Temperature

• Important abiotic factors:– Sediment/Turbidity– Nutrients– Temperature– Substrate

Adaptations to Stream and River Ecosystems:

How have humans impacted Salmon?

Alterations to Stream Habitat

ChannelizationChannelization Fish barriers (roads/bridges)Fish barriers (roads/bridges)

Change in riparian vegetationChange in riparian vegetation

Changes in temperature, flow rate,turbidity, dissolved oxygen, p.p.,substrate, …..

Local Watersheds

http://www.sbck.org/pdf/GSTReport-Background.pdf

Atascadero Creek http://www.sbck.org/pdf/GSTReport-Background.pdf

What’s a Wetland?

Ecotones- contain characteristics of two habitats (in this case, aquatic and terrestrial)

Wetland- a broad term for all the different kinds of wet habitats where the land is wet for some period of time each year but not necessarily permanently wet.

Wetlands of the World

Wetlands: where water meets land

Types of Wetlands:

• Intertidal zone marine wetland

• Estuarine: river mouth + tides= brackish

• Freshwater: swamps, fens, bogs, and vernal pools

Which US state has lost the largest % of its wetlands (1780-1980)?

CA- 91% decline (source: USGS)

U.S. total = 53% decline

• When land is flooded, O2 gets used up by decomposers and the soil becomes anaerobic

• Demand for O2 is still high• Other minerals containing oxygen get reduced

• Reduction is when a compound gains an electron- in this case by giving up an O2 atom

• Some molecules release O2 more easily than others

Wetland Biogeochemistry: Depends on HYDROPERIOD!

O2 NO3- Fe(OH)3 MnO2 SO4

2- CO2

•If the water level drops, O2 enters the soil again, and

the reduced substances can get oxidized

Salt Marsh Biogeochemistry

Wetland Adaptations

Why Should we Care about Wetlands?

Wetland Ecosystem Services

• Food/Jobs

• Important Habitat for Species

• Clean water/Nutrient storage

• Flood control

• Erosion control

• Carbon storage (sink?)

• Tourism

• “No net loss” protection for wetlands?

•How could you calculate the value of a wetland?

What is the value of a wetland?

• “Value” is a human judgement call– Depends on if you are a:

• Developer• Farmer• Engineer• Hunter• Ecologist• Chemical plant owner

Why are Wetlands Diminishing?• Drained or Filled

• Agriculture/residential development/industrial development/oil and gas exploitation

• Lowering of water table

• Polluted• wetlands are in low-lying areas

• Natural causes

Local Watersheds

http://www.sbck.org/pdf/GSTReport-Background.pdf

Goleta Slough

Goleta Slough: Endangered Species + Globally Important Bird Area

Tidewater Goby

CA least tern Red-legged Frog

American peregrine

falcon

Diminishing Wetlands

Salt MarshLake: Santa Barbara Bird Refuge

Penfield & Smith Engineers, Inc.. 1985. Limnological investigation of euthrophication at the Andree Clark Bird Refuge and recommendation for mitigating actions.~135 pp.

“Mother Nature at work,” ? http://www.virtualtourist.com

Other Local Wetland Projects:

• Vernal Pools

• Carpinteria Salt Marsh

• Ormond Wetland

Changing Perceptions of Wetlands

http://www.countyofsb.org/project_cleanwater/Web_Images/South_Turnpike_BMP_Xsection.jpg

Bioswales: mimic wetland processes

Wetland Value and Natural Disaster

Cypress trees mitigate impactsof Hurricane Katrina

Mangroves lessen tsunamiimpacts

Wetlands and Aquaculture: Conversion of Mangroves to Shrimp Farms

Mangrove forests once covered 3/4 of the coastlines of tropical and subtropical countries. Today, less than 50% remain. Many factors contribute to mangrove forest loss, including the charcoal and timber industries, urban growth pressures, and mounting pollution problems. However, one of the most significant causes of mangrove forest destruction in the past decade has been the consumer demand for luxury shrimp

The Rise and Fall of the Blue Revolution: Article by Alfredo Quarto published in the East Africa Wildlife Society's magazine SWARA

AQUACULTURE: The AQUACULTURE: The BlueBlue Revolution? Revolution?

Aquaculture• Status: fastest growing food production industry in the

world (1/3 of all fishery landings)

Aquaculture: Fish Farms

• Energy flow perspective– Fish vs. Cows – Salmon vs. carp vs. filter feeders– Farmed salmon vs. wild salmon

Sustainable Aquaculture?

Sustainable Aquaculture?

Aquaculture: Risks

– Impact on wild fish populations• Feed for farmed fish

• ‘Seed’ for farmed fish

• Fish escapes- invasive species

– Algal blooms

– Oxygen depletion

– Downstream impacts

– Disease

– (Wet)land conversion

Aquaculture: Integrated Systems Approach

Aquaculture: Integrated Systems Approach

BENEFITS:

• Waste = food

• Whole is greater than sum of parts

COSTS/RISKS:

• Pesticide use

• Labor intensive

• Limit to fish density

What Can You Do?

• Vote with your dollars!

• Get involved!

• Educate others!

Summary• Wetland: definition

– Types– Biogeochemistry (just know the basics!)– Ecosystem Services (filtration, C storage, flood control, habitat,

food, tourism, etc)– Human causes of wetland loss– Ecosystem Value… depends on perspective.– Local Wetlands

• Aquaculture– Types– Potential impacts: wetland loss, impact on marine fisheries– Energy flow perspective– Risks– Integrated systems approach