Topic 5 Life in Oceans

Topic 5 Life in Oceans

5.1 Plankton and productivity

Nature of science:

• Looking for patterns, trends and discrepancies has lead scientists to realize the central importance of plankton to marine ecosystems.

Understandings:

• Plankton may be multi-cellular organisms, bacteria, or viruses

• There are autotrophic bacteria as well as phytoplankton

• There is a great abundance of viruses in marine waters.

• Plankton may be photosynthetic and play an essential role in food chains

• Light, temperature and nutrients affect primary production by phytoplankton

• Some phytoplankton cause Harmful Algal Blooms that have effects on marine ecosystems and on human health

• Phytoplankton play in important role in the global carbon cycle

• Zooplankton and heterotrophic bacteria have important roles in marine ecosystems.

Applications and skills

• Skill: Describing and evaluating two methods of sampling plankton.

• Skill: microscopic examination and sketches of phytoplankton and zooplankton (practical 5)

• Skill: calculating the primary productivity, gross primary production & net primary production for an ecosystem from data.

• Skill: Describe and evaluate two methods of measuring primary productivity.

• Analysing marine food webs in terms of carbon cycling with indications of carbon and energy budgets

5.2 Open ocean ecosystem

Nature of science:

• Use theories to explain natural phenomena.

• An understanding of science is vital when society needs to make decisions about fishing and pollution.

Understandings:

• Open ocean ecosystem has distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Adaptations for survival in the open ocean include thermoregulation in marine mammals, buoyancy in diatoms, squid, fish and sea otters, and diving in marine mammals

• Adaptations for feeding in the open ocean include cruising, lunging, echolocation as well as herding and bubble-netting.

• Adaptations for predator avoidance including schooling and counter-shading

• Further adaptations include vertical migration by both phytoplankton and zooplankton, and migrations by salmon, sea turtles, sea birds and mammals

• Other adaptations of interest in the open ocean include mammal communication and bioluminescence

• Human impact on the open ocean includes over-fishing, destructive fishing and bycatch

• Noise pollution, chemical pollution and solid wastes as well as plastic pollution interrupt the health of the open ocean.

Applications and skills:

• Skill: describing named organisms that provide examples of the adaptations application: discussion and evaluation of the problems of pollution and over-fishing.

• Application: study impact of marine plastic debris on Laysan albatrosses

5.3 Rocky shore ecosystem

Nature of science:

• Use models as representations of the real world—zones of stress and limits of tolerance graphs are models of the real world that have predictive power and explain community structure.

Understandings:

• Rocky shore ecosystems have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Changes in water level due to daily tides poses biotic and abiotic problems to intertidal species.

• Biological adaptations include water conservation, protection from wave action, evaporative cooling, spatial refugia, anti-herbivory chemicals, and competition for space; named organisms exhibiting each of these adaptations.

• Tide pools have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Tide pool organisms are eurythermal, euryhaline and euroxic animals; named organisms exhibiting one or more of these adaptations.

• Human impact includes over-harvesting, trampling, alien species, oil spills and coastal development.

Applications and skills:

• Use dichotomous key to identify intertidal species of seaweeds or invertebrates.

• Describe and evaluate methods used to measure intertidal zonation.

• Skill: Quantitative zonation study in the rocky intertidal region including transect and quadrat data and kite diagrams.

• Skill: Apply Simpson's Inverse Diversity Index to data collected at a rocky shore or from on-line data sources comparing zones or different times of year (practical 6).

• Discussion of methods for mitigating human impact on rocky shores

• Skill: developing graphs to show zones of stress and limits of tolerance for named species of rocky shore intertidal zones.

5.4 Estuary ecosystems

Nature of science:

• Use theories to explain natural phenomena.

• Scientists provide information to businessmen, politicians, fishermen and cultural organizations in land use decisions.

Understandings:

• Estuaries may be salt wedge, well-mixed, partially mixed and fjord-type estuaries

• Each type of estuary has distinct characteristics of topography, temperature, salinity, light, nutrients, oxygen, substrate and energy

• Many organisms in estuaries are euryhaline as the salinity of estuaries changes as prominence of tidal influx alternates with river influence

• Estuaries are important as nurseries for many species of fish and invertebrates.

• Human impacts upon estuaries include over-harvesting, alien species, aquaculture, agricultural run-off, coastal development and dam construction, chemical pollution.

Applications and skills:

• Skill: A detailed, quantitative and qualitative study of a selected estuary can be made using a field study or on-line data including both biotic and abiotic components

• Application: discussion of the importance of estuaries as nurseries and the survival of commercially important species including salmon.

• Application: Dredging of estuaries is an issue as many estuaries are naturally filling with soil. What criteria should be used to determine whether or not to dredge an estuary?

5.5 Coral reef ecosystems

Nature of science:

• Use theories to explain natural phenomena.

• Studies of coral reef bleaching have brought surprises to understanding the relationships between symbionts and their coral hosts.

Understandings:

• Coral reefs have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy.

• Formation of coral reefs

• Coral reefs that are located in tropical oceans have narrow abiotic requirements for reef-building corals.

• Corals have mutualistic symbiosis with organisms that are essential to their survival.

• Climate change has a relationship to coral bleaching

• Aquarium and souvenir trades, overfishing, tourism, and chemical pollution are human threats

• Coral diseases, predators including Acanthaster planci.

Applications and skills:

• Skill: drawing a coral reef food web and annotating the trophic levels.

• Application: conducting a survey of saltwater aquarium shop to determine the sources of 10 organisms being sold.

5.6 Polar ocean ecosystems

Nature of science:

• Use theories to explain natural phenomena.

Understandings:

• The polar oceans (Arctic and Southern) have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Adaptations for survival include physical adaptations (blubber, thick coats, small extremities), behavioural adaptations (huddling), physiological adaptations (slow metabolism, lack of red blood cells, antifreeze in fish blood, heat exchangers)

• Resource exploitation, mining, overfishing, sealing and whaling are threats to the ecosystem

• Tourism and pollution also threaten the ecosystem as the sea ice decreases.

Applications and skills:

• Application: describing efforts going into conservation of polar seas by governmental and non-governmental organizations.

• Application: case studies of penguins in the Southern Ocean and/or polar bears in the Arctic Ocean provide clues to the impact of global warming on these species.

• Skill: explore mammalian dive reflex--bradycardia

• Application: satellite monitoring of extent and concentration of sea ice at both poles has been done since 1979 and can be used to correlate with population estimates of polar species.

5.7 Deep sea and hydrothermal vent ecosystems

Nature of science:

• Curiosity has lead to studying the deep ocean and hydrothermal vents. This has produced many unplanned and surprising discoveries.

Understandings:

• The deep sea ecosystems have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Biological adaptations to the deep sea ecosystem include decreased metabolism, special swim bladders, and techniques for finding food, and finding mates; named examples of each adaptation.

• Hydrothermal vents have distinct characteristics of temperature, salinity, light, nutrients, oxygen, substrate and energy

• Biological adaptations to hydrothermal vents include decreased metabolism, sulphide binding (by Riftia hemoglobin) and chemosynthetic mutualistic bacteria; named examples of each adaptation

• Ocean dumping, mineral exploration/extraction and carbon storage all affect deep sea and hydrothermal vent ecosystems.

Applications and skills:

• Locate on a map or globe hydrothermal vents and deep sea ecosystems

• Application: discussion of human impact upon deep sea ecosystems and hydrothermal vents.