RNR chap 6
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: formation produced by massive colonies containing billions of tiny coral animals, called polyps, that secrete a stony substance (calcium carbonate) around themselves for protection. When the corals die, their empty outer skeletons form layers and cause the reef to grow. Coral reefs are found in the coastal zones of warm tropical and subtropical oceans
Talk about Coral reefs are important
some of the most ecologically important aquatic ecosystems on the planet coral polyps and zooxanthellae have a symbiotic relationship, and together they create the complex habitats that are home to so many invertebrates and fishes. They provide ecosystem services related to CO2 fixation, coastal protection, and fisheries production, but it is of such great concern to conservationists.
Natural capital degradation – Coral reefs
- Ocean warming
- Soil erosion
- Algae growth from fertilizer runoff
- Mangrove destruction
- Rising sea levels
- Increased UV exposure
- Damage from anchors
- Damage from fishing and diving
Threats to coral reefs: increasing stress Coral reefs are vulnerable to damage because they grow slowly and are disrupted easily.
Aquatic life zones can be divided by
All of the continents (except Antarctica) have numerous lakes, ponds, rivers, and nearshore marine habitats that have a tremendous diversity of resources such as...
- Ecosystem services in the form of CO2 fixation and biogeochemical cycling
Aquatic food webs...list
- Phytoplankton: small, drifting plants, mostly algae and bacteria, found in aquatic ecosystems
- Zooplankton: animal plankton; small floating herbivores that feed on plant plankton
- Nekton: strongly swimming organisms found in aquatic systems that feed on phytoplankton and zooplankton
- Benthos: bottom-dwelling organisms – substrate dwelling organisms
- Decomposers: organism that digests parts of dead organisms and cast-off fragments and wastes of living organisms by breaking down the complex organic molecules in those materials into simpler inorganic compounds and then absorbing the soluble nutrients. Producers return most of these chemicals to the soil and water for reuse. Decomposers consist of various bacteria and fungi.
- Ultraplankton: huge populations of extremely small photosynthetic bacteria that may be responsible for 70% of the primary productivity near the ocean surface – small bacteria in the ocean that contribute significantly to photosynthesis in the ocean
Limiting factors to photosynthesis in water
- Human activities that affect aquatic primary production
Human activities that affect aquatic primary production
- Dams, diversions, or canals fragment about 40% of the world’s 237 large rivers. They alter and destroy wildlife habitats along rivers and in coastal deltas and estuaries by reducing water flow and increasing damage from coastal storms.
- Flood control levees and dikes built along rivers alter and destroy aquatic habitats
- Cities and farmlands add pollutants and excess plant nutrients to nearby streams and rivers
- Many inland wetlands have been drained or filled to grow crops or have been covered with concrete, asphalt, and buildings
Important marine habitats
all of these are important in terms of primary production, pollution abatement, storm protection, food production, and perhaps most importantly – spawning and nursery grounds for a huge number of ecologically, commercially, and recreationally important invertebrates and fishes
- extends from the high tide mark to the edge of the continental shelf. It provides most of the fisheries, mineral resources, and ocean productivity that
- are important to people
Estuaries and coastal wetlands...
shallow, nutrient-rich systems that are extremely productive, but difficult to adapt to physiologically because of rapid changes in temperature and salinity
replace salt marches in tropical areas. These are being destroyed at a rapid rate by coastal development and shrimp farming – which is not sustainable
extends from the low to the high tide mark, and again provides a physiologically stressful habitat to organisms to deal with, mostly due to drying and rapid changes in salinity and temperature as the tide moves in and out. All coastlines have intertidal areas, but rocky shore intertidal habitats are particularly interesting and have a high diversity of fishes and invertebrates that have adapted to environments that may undergo 5 m. tidal changes twice a day.
Barrier beaches and barrier islands:
fragile, but important habitats – especially for storm protection
Barrier islands: long, thin, low offshore islands of sediment that generally run parallel to the shore along some coasts
Open Ocean areas are...
- Euphotic zone: upper layer of a body of water through which sunlight can penetrate and support photosynthesis. Excess photosynthesis!
- Bathyl zone: separated from the euphotic zone by the compensation depth, where photosynthesis=respiration
- Abyssal: deep, dark, cold
LAKES: In freshwater systems, lakes are somewhat likes small oceans with…
- Littoral zone: shallow zone that extends to the edge of rooted plant beds
- Limnetic zone: like the euphotic zone in the ocean
- Profundal zone: separated from the limnetic zone by the thermocline zone
- Thermocline zone
- Benthic zone: on the bottom
Lakes can be divided in terms of their productivity into trophic states, which range from
- Oligrotrophic: nutrient poor. Lake with a low supply of plant nutrients
- Mesotrophic: lake with a moderate supply of plant nutrients
- Eutrophic: lake with a large amount of excessive supply of plant nutrients, mostly nitrates and phosphates
- Hypereutrophic: subjected to cultural eutrophication, with excessively high nutrient levels
RIVERS AND STREAMS: occur within watersheds (the area that delivers water, sediments, and nutrients to the stream)
- The watershed for the MS River covers almost 65% of the US
- The larger the watershed, the larger the stream, as well as the larger the potential for pollution and habitat problems from human activities.
Stream and river systems…
- Lotic system
- Source zone: where streams and rivers begin.
- Transition zone: streams and rivers travel through this zone
- Floodplain zone: usually near the ocean
- The sediment and water that these systems deliver to the ocean are critical to the maintenance of coastal marshes and deltas
- It is not surprising we are having problems with coastal marsh loss in LA in light of our levee system along the MS River
Provide important ecological services
Filtration of water
- Recharging of freshwater aquifers
- Flood protection
- Water storage
- Support of aquatic and terrestrial biodiversity
- Provide important recreational and commercial resources to people
- Unfortunately, we have not taken care of our wetlands very well, and the effects of their loss have only been fully realized in the last 30 years or so.
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