2Bell Ringer: Ride the Waves The marine ecosystem that is exposed to regular and extreme changes in its surroundings is the intertidal zone. During high tide, the intertidal zone is covered by seawater. During low tide, this area is exposed to air, sunlight, and heat.1. What types of organisms would you expect to find living in the intertidal zone?2. What characteristics do you think these organisms have that enable them to live in this zone?3. What effect do waves have on the intertidal zone?
4What are we learning today? BenchmarkObjectivesSC.912.L.17.2 – Explain the general distribution of life in aquatic systems as a function of chemistry, geography, light, depth, salinity, and temperature.Explain that different types of organisms exist within aquatic systems due to chemistry, geography, light, depth, salinity, and/or temperature.
5What is the essential question? What are the characteristics of aquatic ecosystems?
6What factors affect life in aquatic ecosystems? Aquatic organisms are affected primarily by the water’s depth, temperature, flow, and amount of dissolved nutrients.What factors affect life in aquatic ecosystems?(left) Hawaii’s water temps(right)This figure denotes the temperature and salinity distributions from the edge of the continental shelf out to about the center of the Gulf Stream. The intersection of the colored and white region denotes the bottom. The outer continental shelf is on the left, where the water depth is about 70 m. The maximum water depth occurs at about 55 km offshore.
7Water DepthWater depth strongly influences aquatic life because sunlight penetrates only a relatively short distance through water.The sunlit region near the surface in which photosynthesis can occur is known as the photic zone.The photic zone may be as deep as 200 meters in tropical seas, but just a few meters deep or less in rivers and swamps.“The physical and chemical structure of the ocean provides habitats that marine organisms depend on. Variations in such factors as temperature, light, and nutrient concentration create distinct conditions to which organisms have adapted. For example, the planktonic seaweed in the Sargasso Sea grows slowly and lives a long time, an adaptation to low nutrient concentrations. Fish that live at deeper levels of the ocean have developed bioluminescence and photic organs that help them to cope with low-light conditions.”Figure 1. Divisions of the marine environment. The two large divisions are the benthic realm (organisms that live on the seafloor) and the pelagic realm (organisms that live in the water). The benthic and pelagic environments are subdivided into zones based on depth. From deepest to shallowest, the zones are hadal, abyssal and bathyal zones. In the pelagic environment, the shallowest zone is called the photic or surface zone. In the benthic environment, the shallowest zones are called the intertidal and subtidal zones.NOTE: this diagram has a large amount of vertical exaggeration (slopes look MUCH steeper than they really are).
8Water DepthPhotosynthetic algae, called phytoplankton, live in the photic zone.Zooplankton—tiny free-floating animals—eat phytoplankton. This is the first step in many aquatic food webs.Below the photic zone is the dark aphotic zone, where photosynthesis cannot occur.
10Water DepthMany aquatic organisms live on, or in, rocks and sediments on the bottoms of lakes, streams, and oceans.These organisms are called the benthos, and their habitat is the benthic zone.
11Temperature and Currents Aquatic habitats are warmer near the equator and colder near the poles.Temperature in aquatic habitats also often varies with depth. The deepest parts of lakes and oceans are often colder than surface waters.(both) Trinity River, CA.
12Nutrient Availability Organisms need certain substances to live, such as oxygen, nitrogen, potassium, and phosphorus.The type and availability of these dissolved substances vary within and between bodies of water, greatly affecting the types of organisms that can survive there.(top) The strip of a green alga (Enteromorpha) along this shore indicates that there is a nearby source of nutrients (probably nitrates or ammonia from a small estuary).
13Freshwater Ecosystems What are the major categories of freshwater ecosystems?Freshwater ecosystems can be divided into three main categories: rivers and streams, lakes and ponds, and freshwater wetlandsFreshwater ecosystems include streams, lakes, and freshwater wetlands (bogs, swamps, and marshes).
14Rivers and StreamsRivers, streams, creeks, and brooks often originate from underground water sources in mountains or hills.Animals in many rivers and streams depend on terrestrial plants and animals that live along their banks for food.
15Lakes and PondsThe food webs in lakes and ponds often are based on a combination of plankton and attached algae and plants.Plankton is a general term that includes both phytoplankton and zooplankton.Water flows in and out of lakes and ponds and circulates between the surface and the benthos, distributing heat, oxygen, and nutrients.
16Freshwater WetlandsA wetland is an ecosystem in which water either covers the soil or is present at or near the surface for at least part of the year.Water may flow through freshwater wetlands or stay in place.Wetlands are often nutrient-rich, highly productive, and serve as breeding grounds for many organisms.Freshwater wetlands purify water by filtering pollutants and help to prevent flooding by absorbing large amounts of water and slowly releasing it.
17Freshwater WetlandsThree main types of freshwater wetlands are freshwater bogs, freshwater marshes, and freshwater swamps.Saltwater wetlands are called estuaries.Freshwater BogFreshwater Marsh in CanadaSwamp in Florida
18EstuariesAtlantic coast salt marshEstuaries serve as spawning and nursery grounds for many ecologically and commercially important fish and shellfish species including bluefish, striped bass, shrimp, and crabs.Why are estuaries so important?
19EstuariesAn estuary is a special kind of wetland, formed where a river meets the sea.Estuaries contain a mixture of fresh water and salt water, and are affected by the rise and fall of ocean tides.Many are shallow, which means that enough sunlight reaches the benthos to power photosynthesis.Columbia River Estuary, Cathlamet Bay,
20EstuariesMangrove Estuary in the EvergladesSalt marshes are temperate estuaries that have salt-tolerant grasses above the low-tide line and seagrasses below water.Mangrove swamps are tropical estuaries that have several species of salt-tolerant trees, collectively called mangroves.The largest mangrove area in America is in Florida’s Everglades National Park.
21Marine EcosystemsHow do ecologists usually classify marine ecosystems?Ecologists typically divide the ocean into zones based on depth and distance from shore.Starting with the shallowest and closest to land, marine ecosystems include the intertidal zone, the coastal ocean, and the open ocean.Ecologists typically divide the ocean into zones based on depth and distance from shore.Starting with the shallowest and closest to land, marine ecosystems include the intertidal zone, the coastal ocean, and the open ocean.
22Marine EcosystemsThis diagram shows the different zones in an ocean.
23Intertidal ZoneOrganisms in the intertidal zone are submerged in seawater at high tide and exposed to air and sunlight at low tide.These organisms are subjected to regular and extreme changes in temperature and are often battered by waves and currents.
24Intertidal ZoneA typical rocky intertidal community exists in temperate regions where exposed rocks line the shore.There, barnacles and seaweed permanently attach themselves to the rocks.
25Coastal OceanThe coastal ocean extends from the low-tide mark to the outer edge of the continental shelf—the relatively shallow border that surrounds the continents.Water in the coastal ocean is brightly lit, and is often supplied with nutrients by freshwater runoff from land. As a result, coastal oceans tend to be highly productive.Kelp forests and coral reefs are two important coastal communities.
26Open OceanMore than 90 percent of the world’s ocean area is considered open ocean.Depth ranges from 500 m along continental slopes to more than 10,000m in ocean trenches.The open ocean is divided into two zones based on light penetration—the photic and aphotic.
28The Open Ocean Photic Zone The open ocean typically has low nutrient levels and supports only the smallest species of phytoplankton.Still, because of its enormous area, most photosynthesis on Earth occurs in the sunlit top 100 meters of the open ocean.
29The Open Ocean Aphotic Zone The permanently dark aphotic zone includes the deepest parts of the ocean.
30Exit TicketComplete the handout “Aquatic Ecosystems Exit Ticket”
31What is the essential question? What are the characteristics of aquatic ecosystems?