Test 2 Flashcards
Explain Phytoplankton, Zooplankton, Nekton, and Benthos
Phytoplankton - tiny plants in water that make energy from sunlight and are food for other organisms
Zooplankton - tiny animals in water that eat phytoplankton and are food for bigger animals
Nekton - larger animals like fish and whales that swim freely in the water
Benthos - organisms that live on or near the bottom of aquatic environments, such as oceans, lakes, and rivers. These invertebrates live in the sediment and the fish feed on them.
List four economic services provided by marine ecosystems and provide a brief explanation of each.
Food - marine ecosystems support global fisheries providing seafood, such as fish, shellfish, and seaweed, which are essential for human nutrition and economies worldwide.
Employment - many industries rely on marine ecosystems for jobs, including fishing, tourism, shipping, and marine research. These sectors provide livelihoods for millions of people globally.
Oil & Natural Gas - offshore drilling extracts valuable fossil fuels from beneath the ocean floor, contributing significantly to global energy supplies and economic development.
Recreation - marine ecosystems support tourism and recreational activities such as snorkeling, scuba, diving, boating, and fishing, generating substantial revenue for coastal communities and businesses.
List the three factors that limit life at different depths in an aquatic life zone and explain.
Sunlight - the top layer of water receives the most sunlight, allowing plants and phytoplankton to survive. As depth increases, less light penetrates, limiting photosynthesis and plant life.
Temperature - water is warmest near the surface and gets colder with depth. Many organisms are adapted to specific temperature ranges, affecting where they can survive.
Nutrients - more nutrients are found near the surface and ocean floor, but the middle depths have fewer nutrients.
What is a mangrove forest and what important functions do they serve in tropical coastal areas?
Mangroves are found along tropical coasts and are made up of trees that can take root in saltwater. They collect mud and “build land” and are excellent carbon sinks, which stabilize climate change.
Explain three differences between the biota that you would find in a rocky shore ecosystem compared to a sandy beach ecosystem.
Rocky shore:
- organisms cling to rocks or hide in crevices (barnacles, mussels, crabs)
- Seaweed and other vegetation grow on rocks
- Sedentary species must tolerate being exposed during low tide and have shells to protect them from predators
Sandy beach:
- Organisms burrow into sand for protection (crabs, beach fleas)
- No vegetation on shore due to shifting sand
- Organisms are transient, moving with the tides, and without vegetation, most organisms are scavengers feeding on what is washed up onto the shore
Explain the difference between an oligotrophic lake and a eutrophic lake. Which is better?
Oligotrophic lake:
- Low concentration of nutrients and plankton
- Sparse fish population
- Little shore vegetation
Eutrophic lake:
- High concentration of nutrients and plankton
- dense fish population
- Much shore vegetation
Neither lake is strictly better – they are just different ecosystems. However, if human activity causes excessive nutrient loading, a eutrophic lake can suffer from harmful algal blooms, and poor water quality. An oligotrophic lake has clear water and fewer nutrients, while a eutrophic lake has high productivity, but can become polluted if overloaded with nutrients .
List three types of freshwater wetlands. Why are wetlands so important to both the aquatic and terrestrial environment? That is, what important functions do they perform?
Marshes, swamps and bogs
Wetlands are important for flood control, water filtration, carbon sequestration, and support high biodiversity.
Why is our soil so important to us in the rest of the environment? List three ways in which soil has been degraded and made unusable for agriculture.
Soil supports plant growth by providing nutrients and a home for helpful microbes. It also helps ecosystems by supporting insects and bacteria that recycle nutrients. Since the topsoil layer is thin and fragile, we must protect it for farming and nature.
Three ways in which soil has been degraded and made unusable for agriculture:
- Soil erosion – the removal of topsoil by wind or water, reducing fertility
- salinization – excess salt buildup in soil, making it unsuitable for crops
- desertification – land becomes dry due to overuse and climate change
List two reasons why our current industrialized agricultural practices are unsustainable. Provide a brief explanation of each.
Soil degradation - industrialized farming leads to soil, erosion and nutrient depletion, making the soil less productive
Chemical use - heavy use of fertilizers and pesticides can pollute water sources and harm biodiversity
Explain the difference between industrialized agriculture and traditional agriculture.
Industrialized - large-scale farming with heavy machinery, monoculture crops, and high use of fertilizers and pesticides to maximize yields.
Traditional - small-scale farming, often with mixed crops, low use of machinery, and minimal chemical inputs, focussing on local food production.
What important developments were responsible for the green revolution?
Synthetic fertilizer and pesticides - increased crop yields by providing nutrients and protect protecting plants from pests
Artificial selection - developed plants that grow faster and produce more food
Mechanization - tractors and machines made farming faster and more efficient
Irrigation systems - provided water to crops in dry areas, increasing food production
Genetic engineering - created pest- and drought-resistant crops to improve yields
How do modern agricultural practices damage the soil? What are some of the solutions to these problems?
Soil damage:
Erosion - tilling and removing vegetation e pose soil to wind and water, causing it to wash or blow away
Depletion - continuous mono-cropping and synthetic fertilizers reduce natural nutrients in the soil
Salinization - irrigation can leave salt deposits in the soil, making it unsuitable for crops
Desertification - overuse of land and deforestation turn fertile soil into dry, unproductive land
Solutions:
Conservation tillage - reduces plowing to prevent soil loss
Crop rotation and interplanting - improves soil fertility by alternating crops
Organic farming - uses compost and natural fertilizers instead of chemicals
Windbreaks and terracing - prevents erosion by stabilizing soil with trees and step-like fields
How can food production be made more sustainable?
- stop expanding agriculture
- close yield gaps: make the land already used as productive as it can be
- Increase agricultural resource efficiency
- change food habits (reduce meat, reduce waste)
Why is meat production (particularly beef) so environmentally unfriendly? How does the use of feedlot help make meat production more sustainable?
Meat production, especially beef, is environmentally harmful because it requires large amounts of feed, water, and fossil fuels. It also leads to deforestation, greenhouse gas emissions from methane, and water pollution from animal waste. Feedlots help by using less land, preventing overgrazing, and increasing efficiency through controlled feeding. This reduces the need for deforestation and helps protect natural ecosystems.
Explain the term by-catch with respect to commercial fishing.
By-catch is when you catch and kill a species unintentionally.
Aquaculture provides an opportunity to raise and sell fish commercially, like we would cattle, pigs, and chicken. However, like everything, there are pros and cons. List two advantages, and two disadvantages of using aquaculture to produce “seafood” for human consumption.
Advantages:
- High efficiency and yield
- Low fuel use
Disadvantages:
- Large waste output
- Controlling disease with dense population can be difficult
What is a watershed or drainage basin. How can joint ownership of a watershed lead to conflict between two nations? Explain with an example.
A watershed is the area of land that drains to a particular point along a stream.
When a watershed is shared by two nations, conflicts can arise if one country alters the water flow through dams, irrigation, or industrial use, affecting the other country downstream. For example, the Tigris and Euphrates river basin is shared by Turkey, Syria, and Iraq. Turkey, being upstream, has built dams that control water flow, reducing the amount of water reaching Syria and Iraq. This has led to tensions, as downstream countries rely on the rivers for agriculture and drinking water.
What are some of the primary causes of freshwater shortages?
- dry climate
- drought (prolonged period with 70% lower precipitation and increased evaporation)
- desiccation (drying of exposed soil due to external activities)
- water stress (low availability due to increased demand)
List three ways in which we can combat water shortages by increasing freshwater supplies to affected areas. For each solution that you list provide one disadvantage or potentially negative consequence.
- building dams (can disrupt ecosystems, displaced communities, and reduce water flow downstream)
- Transferring water from another place (can reduce water availability in the source area, harming local ecosystems and communities)
- withdrawing groundwater (groundwater can take years to recharge, so using it too quickly, it can be depleted and lost)
- converting salt water into fresh (expensive and uses large amounts of energy)
Explain 4 ways in which we can make our use of freshwater more sustainable.
Not depleting aquifers - use groundwater at a slower rate than it is replenished so it doesn’t run out
Wasting less water - fix leaks and use water-saving methods
Preserving water quality - keep water clean by preventing pollution
Raise water prices - encourages efficient use and funding better water management
