Unit 5

Stable and Non-extreme:

CORAL REEFS: • Are in less than 1 % of the ocean but have 25 % of known marine life -found in photic zone • Provide abiotic conditions that are close to optimum to producers • Abundance of producers provided foundation for long food chains & diverse food webs • Usually in stable temperate environments (warm) allowing high rate of photosynthesis • Changes in abiotic conditions will change biodiversity: global warming, increase in sediment & toxicity (deforestation of coastal areas) (turbidity), agriculture run-off, pollution ROCKY SHORES: • Better at resisting wave-action and erosion which allows for the support greater number of species • Rock provided good substrate for attachment/less chance to be washed away • Provide protective habitats like rock pools and crevices • Less porous than sandy shore so organisms have less chance of desiccation

Fundamental Principles of Marine Ecology

Ecology - the science that studies how organisms relate to each other and their environment. Includes biology, physics, geology, climatology, oceanography, etc. Takes into account the abiotic and the biotic factors of the environment and their relationship to each other Ecosystems refers to the living organisms and the physical and chemical factors which influences them. Includes biotic and abiotic components Have clearly defined physical boundaries Distinct energy source Community of interacting organisms through which energy is transferred

Extreme:

HYDROTHERMAL VENTS: Extreme b/c the abiotic conditions are outside the tolerance for most organisms to survive Toxins, temp., pH, hydrostatic pressure, and no light High concentration of H2S gas and other minerals (Cu, Fe, Zn) create a toxic environment Waters around HT vents can reach temps of 320 ºC and acidity of 2.8 pH HT vents occur at depths of 4 km (hydrostatic pressure of 300 atms No light- producers (archaebacteria) rely on chemicals for making organic matter Less energy & fewer nutrients to support consumers up the food chain HT vents can clog up/collapse and stop producing chemicals needed for chemosynthesis Extreme environment with LOW biodiversity

Important Terms ~

Habitat Place where organisms live Ecological Niche The role of an organism within an ecosystem Species A group of similar organisms that can interbreed and produce fertile offspring Population Organisms of the same species, living in the same area Community All the different species living in a habitat at the same time Ecosystem Living organisms and the chemical and physical factors which influence them

Biotic

Living components of an ecosystem : producers, consumers, & decomposers

Abiotic

Nonliving components of an ecosystem: geological features - substrate type, topography, & suspended sediments Physical features- temp., exposure to wind and sunlight, hydrostatic pressure, wave actions, tides, currents, light intensity& wavelength Chemical features - inorganic/organic nutrients, pH, salinity

Unstable & Non-extreme:

SAND ON A REEF SLOPE: Reef slopes /walls at the fore front absorb most of the energy & damage from waves and stormy seas • Sandy substrate is easily eroded by currents, waves, and wind • Lack of producer biomass means food chains are short b/c environment can't support higher trophic levels • LOW biodiversity - organisms must burrow in the sand: worms, clams, sand fleas & crabs • Conditions NOT extreme but constantly changing - unstable

Ecological Succession

the series of changes in an ecosystem when one community is replaced by another community as a result of changes in biotic and abiotic factors over a period of time.

Succession - Whale Fall

• A temporary community forms when a whale dies and sinks to the bottom of the ocean floor • The pioneer species are detritivores -sharks, hagfish, & amphipods • Within a year, all the whale's flesh will have been removed • Crabs, small fish, snails & worms then eat the organic remains • Heterotrophic bacteria decomposes the oils in the whales bones • Nutrients are released in the surrounding sediments • Decomposition also releases chemicals used by the chemosynthetic archaebacteria that feed other deep-sea organisms

Succession - Key Points

• Can create a community in a previously uninhabited area • Can regenerate a damaged community • Occurs in all types of ecosystems (forests, ponds, coral reefs, HT vents, etc.) • As communities change there is a corresponding change to the animal communities associated with them.

THREE STAGES IN SUCCESSION:

• Colonizing stage: Pioneer Community- the first organisms to colonize the new habitat appear • Successionist stage(s): biodiversity or species richness increases Communities move through several different Successionist stages: a) Seral stage: new species successfully establishes w/i the community b) Halosere stage: is the entire range of communities that succeed one another at a salt-water site. • Climax stage: complex community of many species is finally formed a) Over time, producers, consumers, and decomposers change b) Less change occurs with time creating a stable ecosystem

Succession - HT Vents

• Nutrients brought up through the vents by hot water precipitate out and settles on the seabed • The first organisms to grow are the chemosynthetic archaebacteria • Tube worms (Tevnia species) are early pioneer species & form symbiotic relationship with the archaebacteria • Tevnia is later replaced with the bigger, faster-growing Riftia (up to 2 m long) • Nutrients produced by the tube worms allow other organisms to colonize the vent community • polychaete worms, octopi, clams, limpets, crabs, hagfish, and vent fish • Complex climax community is established

Succession - Coral Reefs

• Primary & Secondary Succession occurs on coral reefs • Primary succession occurs when volcanoes erupts & lava creates new habitats with no plant life • Corals (pioneer species) are the first to colonize and grow on the lava flow • Secondary succession can occur after destruction via hurricane or due to man via boat damage

Two Types of Succession

• Primary - occurs in newly formed habitats where there has never been a community before • New habitat begins with bare substrate and no life present • Can be natural - new island forms due to underwater volcanic eruption • Can be man made - artificial coral reef • Secondary - occurs on site that have previously supported a community that is no longer there due habitat destruction of some kind. • Fire, volcanic eruption, hurricane, tsunami, etc. • Not all species were destroyed/soil may still be there/seeds may still be found

Tivina & Riftia

• Tevnia are usually white, but this clump of worms is stained brown from iron in the vent fluids. • The largest worm in this clump (with more white color) is a different species - a Riftia tubeworm.

Environment & Biodiversity

• The environment is a major factor that influences the biodiversity of a habitat. • Stable environment - has higher biodiversity with more complex food webs. • If one organisms is lost it will not have a big impact • Unstable environment - has lower biodiversity and simpler food webs. • Losing an organism will have a big impact on the remaining organisms • Non-Extreme - conditions are favorable for most life forms to survive. • Extreme environment - contains conditions that are hard to survive for most known life forms. • may have extremely high or low: temperature, pH, pressure, dissolved gases, radiation