Chapter 7 power point.pptx

Chapter 7

Core Case Study:

Why Should We Care About Coral

Reefs?

• _{Coral reefs form in}

clear, warm coastal waters of the tropics and subtropics.

– _{Formed by massive}

Core Case Study:

Why Should We Care About Coral

Reefs?

• _{Help moderate atmospheric temperature by}

removing CO₂ from the atmosphere.

• _{Act as natural barriers that help protect 14% of}

the world’s coastlines from erosion by battering waves and storms.

• _{Provide habitats for a variety of marine}

AQUATIC ENVIRONMENTS

• _{Saltwater (marine) and freshwater aquatic life}

What Kinds of Organisms Live in

Aquatic Life Zones?

• _{Aquatic systems contain floating, drifting,}

swimming, bottom-dwelling, and decomposer organisms.

– _{Plankton: important group of weakly swimming,}

free-floating biota.

• _{Phytoplankton (plant), Zooplankton (animal), Ultraplankton}

(photosynthetic bacteria)

– _{Nekton: fish, turtles, whales.}

– _{Benthos: bottom dwellers (barnacles, oysters).}

– _{Decomposers: breakdown organic compounds (mostly}

Life in Layers

• _{Life in most aquatic systems is found in}

surface, middle, and bottom layers.

• _{Temperature, access to sunlight for}

photosynthesis, dissolved oxygen content, nutrient availability changes with depth.

Salt water life zones

1. 99.5% of earth’s habitable volume 2. 250,000 known species of marine

plants/animals

SALTWATER LIFE ZONES

• _{The oceans that occupy}

most of the earth’s

surface provide many ecological and

economic services.

Two major life zones

The Coastal Zone:

Where Most of the Action Is

• _{The coastal zone: the warm, nutrient-rich,}

shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf.

• _{The coastal zone makes up less than 10% of the}

world’s ocean area but contains 90% of all marine species.

– _{Provides numerous ecological and economic services.}

Estuaries and Coastal Wetlands:

Centers of Productivity

• _{Estuaries include river}

mouths, inlets, bays,

sounds, salt marshes in temperate zones and mangrove forests in tropical zones.

Mangrove Forests

• _{Are found along}

about 70% of gently sloping sandy and silty coastlines in tropical and subtropical regions.

Estuaries and Coastal Wetlands:

Centers of Productivity

• _{Estuaries and coastal marshes provide}

ecological and economic services.

– _{Filter toxic pollutants, excess plant nutrients,} sediments, and other pollutants.

– _{Reduce storm damage by absorbing waves and}

storing excess water produced by storms and tsunamis.

Rocky and Sandy Shores:

Living with the Tides

• _{Organisms experiencing daily low and high tides}

have evolved a number of ways to survive under harsh and changing conditions.

– _{Gravitational pull by moon and sun causes tides.}

Rocky and Sandy Shores:

Living with the Tides

• _{Organisms in intertidal}

zone develop

specialized niches to

deal with daily changes in:

– _Temperature

– _Salinity

– _{Wave action}

Barrier Islands

• _{Low, narrow, sandy islands that form offshore}

from a coastline.

• _{Primary and secondary dunes on gently sloping}

sandy barrier beaches protect land from erosion by the sea.

Threats to Coral

Reefs:

Increasing

Stresses

• _{Biologically diverse}

and productive coral reefs are

being stressed by human activities.

Threats to Coral Reefs

Ecological and Economic services of Coral

Reefs

• Remove CO₂ from the atmosphere

• _{Help protect costline from erosion}

• _{Support many species of marine like and}

account for 1/10 of the world’s fish catch.

• _{Provide jobs and building materials for some}

of the world’s poorest countries

Vulnerable to damage because:

• _{Grow slowly}

• _{Disrupted easily}

• _{Thrive only in clear, warm, fairly shallow}

waters with high salinity

Biological Zones in the Open Sea:

Light Rules

• _{Euphotic zone: brightly lit surface layer.}

– Nutrient levels low, dissolved O₂ high, photosynthetic activity.

• _{Bathyal zone: dimly lit middle layer.}

– _{No photosynthetic activity, zooplankton and fish live} there and migrate to euphotic zone to feed at night.

• _{Abyssal zone: dark bottom layer.}

Effects of Human Activities on Marine Systems: Red Alert

• _{Human activities are}

destroying or

degrading many ecological and

economic services provided by the

world’s coastal areas.

FRESHWATER LIFE ZONES

• _{Freshwater life zones}

include:

– _{Standing (lentic) water}

such as lakes, ponds, and inland wetlands.

– _{Flowing (lotic) systems}

such as streams and rivers.

Lakes: Water-Filled Depressions

• _{Lakes are large natural bodies of standing}

freshwater formed from precipitation, runoff, and groundwater seepage consisting of:

– _{Littoral zone (near shore, shallow, with rooted}

plants).

– _{Limnetic zone (open, offshore area, sunlit).}

– _{Profundal zone (deep, open water, too dark for}

photosynthesis).

– _{Benthic zone (bottom of lake, nourished by dead}

Effects of Plant Nutrients on Lakes: Too Much of a Good Thing

• _{Plant nutrients from a lake’s environment affect}

the types and numbers of organisms it can support.

– _{Oligotrophic (poorly nourished) lake: Usually newly}

formed lake with small supply of plant nutrient input.

– _{Eutrophic (well nourished) lake: Over time, sediment,}

Effects of Plant Nutrients on Lakes:

Too Much of a Good Thing

• _{Cultural eutrophication:}

– _{Human inputs of nutrients from the atmosphere and}

Lakes: Water-Filled Depressions

• _{During summer and winter in deep temperate}

zone lakes the become stratified into temperature layers and will overturn.

– _{This equalizes the temperature at all depths.} – _{Oxygen is brought from the surface to the lake}

Seasonal Changes in Temperate Lakes

• _{Thermal stratification of deep lakes in}

temperate areas

• _{Summer months: 3 layers}

1. Epilimnion – upper layer, high DO

2. Thermocline- water temps change rapidly with depth, moderat DO

Fall Overturn

• _{Brings nutrients from bottom to surface and}

brings DO from surface to bottom

• _{Spring overturn – briefly nutrients and DO are}

Characteristics of freshwater streams and rivers:

• _{Surface water- precip that does not sink into}

the ground or evaporate

• _{Runoff- surface water that flows into streams} • _{Watershed or drainage basin- the land area}

that delivers runoff, sediment and dissolved substances to a stream

• _{Harrisburg/Concord in Yadkin-PeeDee water}

Freshwater Streams and Rivers:

From the Mountains to the Oceans

• _{Water flowing from mountains to the sea creates}

different aquatic conditions and habitats.

Fig. 6-17, p. 139 Source Zone

Rain and

snow Lake GlacierRapids

Waterfall

Tributary

Freshwater Inland Wetlands:

Vital Sponges

• _{Inland wetlands}

act like natural sponges that

absorb and store excess water from storms and

provide a variety of wildlife

habitats.

Freshwater Inland Wetlands:

Vital Sponges

 _{Filter and degrade pollutants.}

 _{Reduce flooding and erosion by absorbing slowly}

releasing overflows.

 _{Help replenish stream flows during dry periods.}

 _{Help recharge ground aquifers.}

Impacts of Human Activities on

Freshwater Systems

• _{Dams, cities, farmlands, and filled-in wetlands alter and} degrade freshwater habitats.

– _{Dams, diversions and canals have fragmented about 40% of the}

world’s 237 large rivers.

– _{Flood control levees and dikes alter and destroy aquatic}

habitats.

– _{Cities and farmlands add pollutants and excess plant nutrients to}

streams and rivers.

– _{Many inland wetlands have been drained or filled for agriculture}

Bad News

• _{Everything that goes in a watershed ends up in}

Good News

• _{Aquatic life zones are constantly renewed}

• _{Water is purified naturally by hydrologic cycle} • _{Nutrients cycle in and out}

• _{Populations can be replenished if given}