GEO-SCI 103 Lecture 18Outline of Current Lecture: Fertile Oases: coastal ecosystems and coral reef ecosystems (11/13/14) pages (190-191, 196-197, 206-207)I. Coastal Ecosystems: Highly Productive but VulnerableA. Zones in the WaterB. Coastal HabitatsII. Coral Reef Ecosystems: Rainforests of the SeaA.Important components of coastal ecosystemsB.Biologically diverse ecosystemC.Coral reefsIII.Decline of Coral ReefsA.DamageB.Coral BleachingCurrent LectureI. Coastal Ecosystems: Highly Productive But Vulnerable Coastal habitats are rich in life because of the abundance of nutrients that stimulates vigorous productivity. The primary producers in the coastal ecosystems include representatives of 3 kingdoms of life: 1. Autotrophic bacteria (Monera) 2. Single Celled Protists and multicellular algae (Protoctista) and 3. True Vascular plants (plantae)A. Zones in the Watera) Littoral Zone: area between low and high tide also called the intertidal zoneb) Supratidal zone is the area just above high tide which is affected bysalt water spray along rocky coasts or occasionally by exceptionally high tides or by storm surges c) Estuaries: areas where freshwater meets seawater in the lower reaches and mouths of rivers as well as bays1. Formed when rising sea level floods the lowermost parts of the riverThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.d) River Deltas: accumulations of sediment (sand and mud) at the mouth of a river. Size and shape is determined by the balance between wave energy and the volume of sediment that is transported by the river to the oceane) Tidal Mud Flats: intertidal areas choked with mud; found along low energy shorelines and estuaries. f) Salt marshes are tidal mud flats vegetated by salt grasses found along low energy shorelines and estuariesg) Mangrove swamps are intertidal areas vegetated by mangrove trees; found along low energy shorelines of estuaries of tropics and subtropicsh) Beaches and duns are high energy shorelines where sand is on the move created by longshore drifi) Barrier islands and spits are low lying ribbons of sand created by longshore drifj) Coral reefs are rigid structures of calcium carbonate built by colonial corals and calcareous algae that support biologically diverse communities of organisms in the photic zone of tropical waters k) Lagoons are shallow bodies of water separated from the open ocean by barrier island/spit or reef. B. Coastal Habitats: typically characterized by reduced salinity because of influence of river runoff. Estuaries, in particular experience daily and seasonal changes in salinity due to flood of tides as well as runoff and seasonal changes in precipitation and snow melt. a) Littoral Zone= intertidal zoneb) Inner Subnertic Zone: within the photic zone attached with benthic algae and plantsc) Base of Food Chain in Coastal Waters1. Phytoplankton 2. Benthic microscopic autotrophs3. Benthic algae4. Detritusd) Coastal habitats can be subdivided into three distinct zones that have different environmental characteristics and support different communities of organismse) Primary productivity is high with different organisms at the base of the foods chainf) Brackish water refers to the mixture of fresh and salt waters. Many coastal organisms are euryhaline: they are adapted to a broad range of salinity conditions g) The various environments that develop along a coastline are dependentupon the amount of freshwater and sediment influx, wave action and tidal range II. Coral Reef Ecosystems: the Rainforests of the SeaA. Important components of Coastal Ecosystemsa) Consist of wave resistant, rigid structures of alcium carbonate, built by colonial corals and calcareous algae that support biologically diverse communities of organisms in the tropical photic zone b) Develop in warm clear waters with normal to slightly elevated levels of salinityc) Shallow platforms fringing continents and volcanic islands d) Atolls (rings of coral reefs enclosing shallow lagoons) form when volcanic islands subsided below sea level and coral reef growth continued upward into photic zone B. Biologically diverse Ecosystema) Highly productive despite limited amount of nutrients b) Efficient at recycling nutrients and capitalizing on symbiotic relationships at all levels of intricate food webs c) Symbiosis is a term to describe the intimate coexistence of two differentorganisms (common in coral reefs)C. Coral Reefsa) Indo-Pacific Coral Reefs1. More diverseb) Atlantic Reefs1. Calcareous algae are minor frame builder of Atlantic reefs2. Lack many of the invertebrate species of the indo-pacific includingnumerous coral species c) Reef Core: coral reef is characterized by a high energy reef core (or tolerance) composed of the frame building corals as well as calcareous algae which encrust and bind reef structured) Low energy back reef and shallow lagoon may contain small patch reefse) Benthic Life in Coral Reef1. Corals, sponges, calcareous algae, anemones, clownfish etc. f) Pelagic Life in Coral Reef:1. Eel, angelfish, scorpion fish, puffer fish, trigger fish, sharks, rays, sea nettles III. Decline of Coral ReefsA. Damagea) 30% of coral reefs worldwide are already severely damagedb) Physical damage can come from channeling through the reefs to provide entrance to a harbor, collisions of boats, c) Overfishing of coral reefs reduced stocks of fish that normally feed on algaed) Human coastal population increases, nutrients that enter the coral reefsincreases and causes algae to grow and overwhelm environmente) Excessive sediment produced by coastal development reduces levels of sunlit penetrationB. Coral Bleaching:a) When the coral animals become stressed (especially through overheating), they expel their symbiotic photosynthetic algae (zooxanthellae) b) Afer bleaching occurs corals grow more slowly, have higher morality rate and do not reproduce wellc) Greenhouse gasses cause pH levels of surface waters to decrease resulting in weaker coral