BIO 1108 Unit Two Great Barrier Reef Biodiversity Interactions o Coral Reefs o Biodiversity Ecosystems Abiotic Biotic Factors Keystone Species Species Wave resistant structures notable for their species richness and ecological complexity They are unique in being formed entirely by the biological activity Hermatypic corals Responsible for reef building Deposit hard calcareous material for their skeletons forming the base work for a coral reef Stony corals Normally contain zooxanthellae symbiotic photosynthetic Restricted in distribution by water temperature and water quality Confined to tropics and sub tropics where calcification rates are greatly dinoflagellates enhances Ahermatypic corals Soft corals Do not build reefs may not contain zooxanthellae Not restricted by water temperature and water quality Autotroph v Heterotroph Metabolism Type is determined by where the carbon comes from o Autotrophs Inorganic C CO2 Zooxanthellae o Heterotophs Organic C C H Anything alive or that used to be alive Coral polyps Reefs grow best in warm marine shallow clear sunny and agitated waters Tropics of Cancer and Capricorn o Due to light regime and how the sun can strike these areas directly o Additional factor is global ocean currents water is pushed westward as the Earth rotates eastward Coriolis effect Some exceptions farther from the equator because of warm currents flowing out of the tropics o Found on continental shelves near islands or on seamounts due to light depth density Why are coral reefs important Rich biodiversity Occupy less than 0 1 ocean s surface but 25 of all marine species spend at least part of their lives on a reef depending on it for food shelter and protection Provide economic and environmental services worth billions o Seafood Nurseries for much of the fishery industry o Shoreline protections from erosion During hurricanes and cyclones o Tourism o Recreation o Medicine They dissolve CO2 from the water and pull it out from the atmosphere a very important service How do we study their biodiversity Ecology oikos home logos to study o Various levels global ecology landscape ecology etc o GBR is ecosystem ecology Scale o There is no defined size of an ecosystem An ecosystem is a community of interacting organisms and their physical environment Abiotic and Biotic Components o Environment Abiotic o Terrestrial Aquatic Substrate Solar radiation Water Geology cid 0 Soils cid 0 Available nutrients Amount and Periodicity related to latitude Amount and periodicity Salinity pH turbidity and sediment load available nutrients Temperatures Disturbance Means extremes seasonality Natural and human Scale and Frequency Tornados cyclones hurricanes earthquakes volcanos landslides humans etc Wave action cyclones hurricanes humans o Organisms Biotic Biodiversity Keystone species Foundation species Species interactions Predator prey Pathogens Competition Symbiotic relationships Parasitism o o Mutualism o Commensalism 0 Facilitation Invasive species o Food webs Photosynthesis is the basis for all life o Abiotic requirements for photosynthetic organisms Light water about 20 elements o Requirements for an essential elements A plant cannot complete life cycle without element No other element can complete the function of said essential element Element is essential in plant nutrition Coral Reefs Abiotic o Hard substrate o Optimal solar radiation o Narrow temp range Shallow waters where water can penetrate can be deeper if the water is very clear Red light absorbed first then blue much later Needed for zooxanthellae to photosynthesize Sunlight fuels all life Extremes v means cannot survive outside its physiological tolerance range Biogeography cannot contradict ecology Must be able to survive throughout the full range of environmental extremes A species that cannot survive the hottest summer day or coldest winter night will not survive in that ecosystem Temperature ranges can be much more different even if they have the same averages o Narrow salinity range Salinity averages 3 5 in the GBR High levels optimal Biggest problem for salinity is heavy rainfall o Narrow range of pH o Low sediment load in water o Carbon O2 nitrogen phosphorus Like all living organisms coral are composed of C H O Also need N P S Composed of proteins fats waxes lipids carbs and minerals Organism that can survive during the adult stage but cannot produce progeny that can also survive in that environment they will fail to become established If the water temperature exceeds the normal range for corals corals quickly die and coral bleaching occurs GBR Extremes Coral reef ecology Water surrounding the reef is normally low in nutrients clear water Low nutrient column means that the water surrounding the reed does not support the degree of primary production by phytoplankton seen in other marine communities Food chain is based on the primary production of zooxanthellae in polyps and gives the corals carbs and the corals give co2 n p Where does nitrogen come from Nitrogen often a limiting factor Cyanobacteria present on the reed are able to fix nitrogen which is available for other inhabitants of the reef o N is needed for chlorophyll DNA RNA amino acids neurotransmitters Diversity of coral reefs Invertebrates o o Vertebrates Keystone species Sponges bryozoans sea squirts cnidarians soft corals mollusks echinoderms crustaceans worms Fish sea turtles sea snakes salt water crocs seabirds mammals In which other species in an ecosystem largely depend If it were removed the ecosystem would change drastically Disproportionate impact when compared to its abundance E g apex predator Foundation species Strong role in structuring the ecosystem Usually a primary producer Corals Stony corals are the basis of reef structures Coral reed cannot persist without zooxanthellae Coral polyp is a keystone species Zooxanthellae is a foundation species HPV and Denisovans 6 11 genital warts o HPV 16 18 most oncogenic o o Vicariance distribution of ratite birds due to vicariance and continental drift o Gardasil 6 11 16 18 Community Ecology o o Is how we study an assemblage or association of populations of two or more different species occupying the same geographical areas and their relationships with each other Interspecific interactions Competition Predation Herbivory Symbioses o Ecological Niche If an organism s habitat is its address the niche is the organism s profession Represents the sum of a species use of the biotic and abiotic resources in its