AQUATIC BIOMES

Biomes- Groups of ecosystems with organisms adapted to particular abiotic factors. So, abiotic factors determine the biome! Aquatic Biomes are characterized by: Salinity- Freshwater, Saltwater, or Brackish Flow- standing or moving Depth of light penetration Temperature Pressure

AQUATIC BIOMES  largest part of biosphere  nearly 75% of Earth’s surface  boundaries between biomes indistinct  more complex food webs than terrestrial biomes different depths add 3 rd dimension to food webs photosynthesis confined to surface water difficult to study vast and deep ocean (Moon, Mars better studied than ~95% of ocean) 3

Marine Biomes -Open ocean, coastal zones -Algae supply much of world’s O 2 -Take in large amounts of CO 2 (photosynthesis, gas dissolution) -avg 3.5% salinity (mostly Na + and Cl - ) Freshwater Biomes -Flowing water (streams, rivers) -Standing water (ponds, lakes) -< 1% salinity -Organisms that cannot survive larger salt concentrations Wetlands Boundary regions between terrestrial and aquatic biomes Regions of wet topographic depressions

Types of Aquatic Biomes Wetlands: Tidal wetlands Nontidal wetlands Wetlands: Tidal wetlands Nontidal wetlands Marine Aquatic Biomes: Coral reefs Kelp forests Open oceans Freshwater Aquatic Biomes: Lakes and Ponds Rivers & Streams Freshwater Aquatic Biomes: Lakes and Ponds Rivers & Streams

Marine Biomes Intertidal Zone (alternating wet/dry)Neritic Zone (over continental shelf) Open Ocean (surface to depth) Benthic Zone (entire seafloor)

Intertidal Zone (alternating wet/dry ) Narrow band of coastline that exists between the levels of high tide an low tide. Waves that crash onto the shore in this biome can make it a challenge for organisms to hold on and not get washed away. Rocky – adaptations for clinging/hiding ex. starfish, anemones, crabs Sandy – adaptations for burrowing ex. worms, sand crab and birds adapted to feeding

Neritic Zone (over continental shelf) Found in warm, shallow waters beyond the shoreline. Earth's most diverse marine biome even though coral reefs are found in water that is relatively poor in nutrients and food. Coral Reefs – tropical clear warm water - polyps secrete CaCO 3 shells - algae live in soft tissue (mutualism) Kelp Forests – rocky w/ cold upwelling water - algae “trees”

The Open Ocean The depth that light can penetrate in the open ocean is dependent on the amount of sediment and algae suspended in the water. Photic zone- the zone that receives enough light to allow photosynthesis to occur. Aphotic zone- the deeper water that lacks sufficient light for photosynthesis. Chemosynthesis- The process that occurs in the aphotic zone when some species of bacteria use methane and hydrogen sulfide to generate energy. The depth that light can penetrate in the open ocean is dependent on the amount of sediment and algae suspended in the water. Photic zone- the zone that receives enough light to allow photosynthesis to occur. Aphotic zone- the deeper water that lacks sufficient light for photosynthesis. Chemosynthesis- The process that occurs in the aphotic zone when some species of bacteria use methane and hydrogen sulfide to generate energy.

Open Ocean Photic Zone – well lit - high DO (low CO2) - phytoplankton - some large nekton (whales, sharks) - many small nekton Disphotic downward into darkness - water T down to 4° C - zooplankton, small nekton rise to shallow water at night to feed Aphotic Zone – complete darkness - high pressure, low DO, low nutrients - water T near 4° C - nekton and benthos dependent on “marine snow” – organic debris raining down from surface region -unusual adaptation of bioluminescence earthguide.ucsd.edu biology.duke.edu oceanexplorer.noaa.gov

FRESHWATER BIOMES

Freshwater Biomes Land Ocean Flowing Water Standing Water Stream tributaries (like in inset) form the watershed - steeper topography - faster, colder flow - higher DO River meanders in floodplain - flat topography - slower, warmer flow - lower DO Ponds and lakes have depth Estuary fresh and saltwater mixing (brackish water)- salinity gradient from river to ocean

Lakes & Ponds Standing water Might be too deep to support photosynthesis Lakes are larger than ponds but there is no clear point at which a pond is considered large enough to be called a lake.

Fig. 4.29b Diagram of lake Standing water Littoral – region of emergent plants Limnetic Zone – photic zone Profundal Zone – aphotic zone

Lakes and Ponds Littoral zone- the shallow area of soil and water near the shore where algae and emergent plants grow. Limnetic zone- open water, where rooted plants can no longer survive. Phytoplankton are the only photosynthetic organisms. This zone extends to as deep as sunlight can penetrate. Profundal zone- the zone where sunlight cannot penetrate and therefore producers cannot survive. Benthic zone- the muddy bottom of a lake or bond beneath the limnetic and profundal zone. Littoral zone- the shallow area of soil and water near the shore where algae and emergent plants grow. Limnetic zone- open water, where rooted plants can no longer survive. Phytoplankton are the only photosynthetic organisms. This zone extends to as deep as sunlight can penetrate. Profundal zone- the zone where sunlight cannot penetrate and therefore producers cannot survive. Benthic zone- the muddy bottom of a lake or bond beneath the limnetic and profundal zone.

Rivers & Streams Flowing Many originate from snow melt Change with the land and climate through which it flows Few plants can survive –mosses with rhizoids to anchor Consumers must rely on leaves & seeds that fall into the water Animals have to be strong enough to fight the current –Fish like trout or minnows

Wetlands Regions of wet topographic depression Land covered by water all or part of the year Any region of saturated soil- tidal and freshwater Boundary between terrestrial/aquatic biomes and poorly drained depression Sustains vegetation adapted to saturated soil

Wetlands Wetlands used to be considered wasteland for disease-carrying insects Many were drained, filled, and cleared for farms or residential and commercial development. The Florida Everglades used to cover 8 million acres; now cover less than 2 million acres 18

Benefits of Wetlands 1.They trap and filter sediments, nutrients, and pollutants, keeping them from entering lakes and oceans 2.They reduce flooding, protect agriculture, roads, buildings, and human health and safety 3.They buffer shorelines against erosion 4.They provide spawning grounds and habitat for commercially important fish and shellfish 5.They provide habitat for rare, threatened, and endangered species 6.They provide recreational areas for fishing, bird-watching, hiking, canoeing, photography, … 19

Wetlands tidal (estuarine) tidal (coastal) nontidal (inland) Importance water filtration slows runoff, sediments deposit, high productivity abundant decomposers “nature’s sewage treatment” protective cover for aquatic and terrestrial species (eggs, larvae, juveniles “nature’s nursery”) floodplains lake shores poorly-drained depressions

Tidal Wetlands Swamp - tropical/subtropical, salt- tolerant trees -“mangrove forest”, “mangrove swamp” Marsh -temperate salt-tolerant grass (cordgrass) -“salt marsh”, “salt meadow” Fig Fig. 4.32

Nontidal Wetlands swamp: mainly floodplains, seasonal high water “bottomland hardwood forest” cypress, tupelo trees w/ buttresses marsh: floodplains, lakeshores “freshwater marsh”, “wet meadow” wet depressions, some wet only 10% of year “prairie potholes”, central U.S. “bog” – high elevation or latitude (cold) low decomposition, abundant peat moss