RNR chap 6

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.

• Ocean warming
• Soil erosion
• Algae growth from fertilizer runoff
• Mangrove destruction
• Bleaching
• 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.

• Salinity
• Flow
• Temperature
• Depth

• Food
• Minerals
• Oil
• Transportation
• Recreation
• Ecosystem services in the form of CO2 fixation and biogeochemical cycling

• Phytoplankton: small, drifting plants, mostly algae and bacteria, found in aquatic ecosystems
• Zooplankton: animal plankton; small floating herbivores that feed on plant plankton
• (phytoplankton)
• 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

• Light
• Nutrients
• 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

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

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.

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

• 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

• 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

• 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

• 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.

• 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.