Major Factors in Aquatic Ecosystems Temperature -decreases with depth -affects dissolved gases, rates of chemical reactions, & where organisms can live Light (solar radiation) -decreases with depth -essential for photosynthesis Nutrient availability -limiting macronutrients: phosphorus & nitrogen -limiting micronutrients include iron -essential for growth of phytoplankton © Brooks/Cole Publishing Company / ITP

Major Factors in Aquatic Ecosystems Dissolved carbon dioxide -essential for growth of phytoplankton -varies with temperature, producers, & consumers Dissolved oxygen -essential for respiration of organisms -varies with temperature, producers, & consumers © Brooks/Cole Publishing Company / ITP

Properties of Water liquid over wide temperature rangeliquid over wide temperature range only natural substance on Earth that can be found in all 3 states: solid, liquid, and gasonly natural substance on Earth that can be found in all 3 states: solid, liquid, and gas high heat contenthigh heat content dissolves a wide variety of compoundsdissolves a wide variety of compounds high surface tension, high wetting ability, strong capillary actionhigh surface tension, high wetting ability, strong capillary action maximum density at 4º Cmaximum density at 4º C expands when freezesexpands when freezes © Brooks/Cole Publishing Company / ITP

Saltwater Ecosystems Oceans cover 71% of Earth’s surface ocean currents distribute solar energy (heat) reservoir for CO 2 regulates temperature of troposphere habitat for plants & animals critical food source for humans communal dumping ground Fig. 6–21 © Brooks/Cole Publishing Company / ITP

Types of Organisms Plankton Plankton Weakly swimming Weakly swimming Free-floating Free-floating Mostly phytoplankton (plant plankton) and zooplankton (animal plankton) Mostly phytoplankton (plant plankton) and zooplankton (animal plankton) From Greek planktos, meaning “drifter” From Greek planktos, meaning “drifter”

Types of Organisms Nekton Nekton Strong swimming consumers Strong swimming consumers Ex: fish, turtles, whales Ex: fish, turtles, whales From Greek nektos, meaning “swimming” From Greek nektos, meaning “swimming”

Types of Organisms Benthos Benthos Bottom-dwellers Bottom-dwellers Anchor themselves to one spot Anchor themselves to one spot Burrow into the sand Burrow into the sand Walk on the bottom Walk on the bottom Ex: crabs, worms, oysters Ex: crabs, worms, oysters From Greek benthos, meaning “depth” From Greek benthos, meaning “depth”

Types of Organisms Decomposers Decomposers Primarily bacteria Primarily bacteria Breakdown complex molecules into simpler ones Breakdown complex molecules into simpler ones

Identify the organisms as plankton, benthos, decomposers, or nekton: Sponges Sponges Diatoms Diatoms Fish Fish Turtles Turtles Lobsters Lobsters Bacteria Bacteria Mussels Mussels

Ocean Life Zones defined by amount of solar radiation zones (in order of declining solar radiation): -euphotic zone (lots of light – photosynthesis) -bathyal zone (some light – twilight) -abyssal zone (darkness) © Brooks/Cole Publishing Company / ITP

Extend from high-tide mark to edge of continental shelf Extend from high-tide mark to edge of continental shelf Entirely within the euphotic zone and include estuaries, wetlands, barrier islands, & coral reefs Entirely within the euphotic zone and include estuaries, wetlands, barrier islands, & coral reefs Nutrient-rich Nutrient-rich High primary productivity: sunlight and nutrients from land, upwelling, & ocean currents High primary productivity: sunlight and nutrients from land, upwelling, & ocean currents Sites of most commercial fisheries Sites of most commercial fisheries Coastal Zones (see Fig. 6–22) © Brooks/Cole Publishing Company / ITP

Estuary Where salt water mixes with freshwater from land, generally at mouth of a river

Coastal Wetland Area of coastal land covered all or part of the year with salt water

Importance: Nutrient-rich High primary productivity Nurseries for fish & other aquatic animals Breeding areas for waterfowl & shorebirds Filter water pollutants Estuaries & Coastal Wetlands © Brooks/Cole Publishing Company / ITP

Human Impacts: World has lost over half of its estuaries & coastal wetlands Percentage lost in U.S. higher; most lost to coastal development Degradation due to urban runoff, sewage effluent, sediment & chemical runoff from agricultural lands Estuaries & Coastal Wetlands © Brooks/Cole Publishing Company / ITP

Think About It 40% of the world’s population live along coasts or within 62 miles of a coast 40% of the world’s population live along coasts or within 62 miles of a coast 13 of 19 megacities (pop. >10 million) are in coastal zones 13 of 19 megacities (pop. >10 million) are in coastal zones By 2030, at least 6.3 billion people will live in or near coastal areas By 2030, at least 6.3 billion people will live in or near coastal areas

What Are Coral Reefs? located in coastal zones of tropical oceans formed by mutualism between polyps & algae polyps secrete hard limestone deposits that remain when polyps die Coral Reefs © Brooks/Cole Publishing Company / ITP

Importance: high biodiversity, like “tropical rain forests of ocean” protect coastlines from storms & high waves nurseries for many fish species Fig. 6–29 Coral Reefs

Vulnerability: slow growing easily disturbed thrive only in clear water Human Impacts: sediment runoff & effluent increased UV radiation fishing with cyanide & dynamite Coral Reefs © Brooks/Cole Publishing Company / ITP

Coral Reef Distribution

Lakes Lakes: large bodies of standing fresh water formed when precipitation, runoff, or groundwater seepage fills depressions in the Earth’s surface Lakes: large bodies of standing fresh water formed when precipitation, runoff, or groundwater seepage fills depressions in the Earth’s surface

Nutrients in Lakes

Oligotrophic – poorly nourished Oligotrophic – poorly nourished oligo (small, little, few) oligo (small, little, few) trophe (nutrients, food) trophe (nutrients, food) Deep Deep Clear water Clear water Very little life Very little life Low productivity Low productivity High in oxygen High in oxygen

Nutrients in Lakes Eutrophic – well-nourished Eutrophic – well-nourished eu (good, well) eu (good, well) trophe (nutrients, food) trophe (nutrients, food) Shallow Shallow Murky water Murky water Lots of algae Lots of algae High productivity High productivity Low in oxygen Low in oxygen

Phosphorus added

Nutrients in Lakes Mesotrophic – in between oligotrophic and eutrophic Mesotrophic – in between oligotrophic and eutrophic mesos (middle, intermediate) mesos (middle, intermediate) trophe (nutrients, food) trophe (nutrients, food)

Nutrients in Lakes

Fig. 6–26 Streams & Rivers Precipitation that does not sink into the ground or evaporate is known as surface water Precipitation that does not sink into the ground or evaporate is known as surface water Streams flow downhill due to gravity and can join together to form rivers Streams flow downhill due to gravity and can join together to form rivers Streams and rivers can shape the land through erosion Streams and rivers can shape the land through erosion

Fig. 6–26 What is a watershed?

Watershed/Drainage Basin

Fig. 6–26 Freshwater Inland Wetland Inland wetlands are covered with fresh water all or part of the time (except for lakes, reservoirs, and streams/rivers) Inland wetlands are covered with fresh water all or part of the time (except for lakes, reservoirs, and streams/rivers) They include marshes, swamps, floodplains, bogs, etc. They include marshes, swamps, floodplains, bogs, etc. 53% of inland wetlands around in the 1600s no longer exist 53% of inland wetlands around in the 1600s no longer exist

Fig. 6–26 How have humans impacted freshwater life zones?

Runoff Video

Long, low offshore islands of sand that run parallel to the shore Fig. 6–26 Importance Protect mainland from storms Shelter bays, estuaries, & wetlands Recreation & residential areas Barrier Islands © Brooks/Cole Publishing Company / ITP

Where do we have barrier islands near us?

Stone Harbor Avalon

Human Impacts: Development Development - destroys dunes & dune vegetation - causes beach erosion - destroys or degrades wildlife habitat, like nesting birds Protection Protection - jetties & seawalls - beach replenishment - replanting dune vegetation - controlling development Barrier Islands © Brooks/Cole Publishing Company / ITP

Barrier Islands are Dynamic After a hurricane in 1933, the U.S. Army Corps of Engineers constructed two jetties After a hurricane in 1933, the U.S. Army Corps of Engineers constructed two jetties Assateague Island has changed dramatically since the construction Assateague Island has changed dramatically since the construction

Human Efforts to Stop Erosion Jetties, seawalls, and beach replenishment are usually just temporary fixes Jetties, seawalls, and beach replenishment are usually just temporary fixes