Sustainability Week 4

Question 1

Fishery

Answer 1

A commercially harvestable population of fish within a particular ecological region

Question 2

Fishery collapse

Answer 2

The decline of a fish population by 90 percent or more

Question 3

Bycatch

Answer 3

The unintentional catch of nontarget species while fishing

Question 4

Bottom Trawling

Answer 4

A type of fishing net that’s pulled along the seafloor. Dragging heavy gear across the seabed can also damage sensitive seafloor habitat. Problem: bycatch. Solutions: Changing the size of the mesh to catch adult fish not juveniles. Using square meshes which do not close when the net is towed. This will allow non-target species to escape.

Question 5

Gillnet fishing

Answer 5

Gillnetting uses curtains of netting that are suspended by a system of floats and weights; they can be anchored to the seafloor or allowed to float at the surface. The netting is almost invisible to fish, so they swim right into it. Gillnets are often used to catch sardines, salmon and cod, but can accidentally entangle and kill other animals, including sharks and sea turtles.

Question 6

Longline fishing

Answer 6

Longlining employs a central fishing line that can range from one to 50 miles long; this line is strung with smaller lines of baited hooks, dangling at evenly spaced intervals. Longlines can be set near the surface to catch pelagic fish like tuna and swordfish, or laid on the seafloor to catch deep-dwelling fish like cod and halibut. Many lines, however, can hook sea turtles, sharks and seabirds that are also attracted to the bait. By sinking longlines deeper or using circle hooks, fishermen can reduce the bycatch problem.

Question 7

Dredging

Answer 7

Dredges are large, metal-framed baskets that are dragged across the seafloor to collect shellfish like oysters, clams and scallops. In order to lift the catch into the basket, metal teeth dig into the seafloor, which can significantly impact seafloor habitat and bottom-dwelling species. Solution: don’t dredge near breeding grounds and nurseries.

Question 8

Aquaculture Pens

Answer 8

Pens are structures that hold farmed fish in open water as they grow. They’re made with wooden, mesh or net screens, which allow water to flow freely through them.

Question 9

Aquaculture Ponds

Answer 9

Ponds enclose fish in a coastal or inland body of fresh or saltwater. Shrimp, catfish and tilapia are commonly raised in this manner. Wastewater can be contained and treated. However, the discharge of untreated wastewater from the ponds can pollute the surrounding environment and contaminate groundwater.

Question 10

Aquaculture

Answer 10

The breeding, rearing, and harvesting of fish, shellfish, algae, and other such organisms. Pros: efficient and requires only small areas of water. Cons: can contaminate water, and fish can escape and may outcompete or breed with wild fish

Question 11

Aquaculture Recirculating Systems

Answer 11

Recirculating systems raise fish in tanks in which water is treated and recycled through the system. Almost any finfish species such as striped bass, salmon and sturgeon can be raised in recirculating systems. Recirculating systems address many environmental concerns associated with fish farming—fish cannot escape, and wastewater is treated—but they are costly to operate and rely on electricity or other power sources.

Question 12

Overfishing

Answer 12

When fish are caught faster than they can reproduce, making it hard to maintain healthy population number

Question 13

Tilling

Answer 13

The act of mechanically breaking up the soil to prepare for planting. Plant roots need to be able to spread in the soil so it can’t be compact.

Question 14

Slash and Burn Agriculture

Answer 14

Clearing out grassland or forest and burning the remaining brush. A layer of ash is left that provides nutrients to added crops. The nutrients from the ash only last for 1 or 2 years before they are depleted.

Question 15

Salinization

Answer 15

Salinization can occur with any watering method. There are naturally occurring salts in irrigated water. When land is watered, and the water evaporates, the salts are left on the soil. Over time, the salts build up and make it difficult for plants to grow. The solution is flooding the land with water that has little to no salts so the water carries the salts away in runoff or deeper into the soil via leaching.

Question 16

Aquifer

Answer 16

An aquifer is a layer of rock that contains water with the ability to flow. The only way for an aquifer to recharge is by surface water seeping into it. This process takes time. When there is a large amount of paving on the land surface, water runs off quickly to nearby lakes and streams, but is not able to seep into the deeper layers of rock.

Question 17

Mulching

Answer 17

Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be organic – such as grass clippings, straw, bark chips, and similar materials – or inorganic – such as stones, brick chips, and plastic.

Question 18

Water Holding Capacity (Porosity)

Answer 18

Description: This is the amount of water the soil can hold due to the amount of pore or air space. A physical soil test can be done to determine the soil’s porosity. Problem: if soil cannot retain water within the reach of plants’ roots, plants will need frequent rains or irrigation. Solution: mulching, tillage, adding gypsum aka green sand.

Question 19

Gypsum AKA Green Sand

Answer 19

It improves water penetration (drainage) and aeration for packed-down and clayey soils by making the fine particles of clay stick together and neutralizing the salt in high-sodium soils without raising the pH as lime does.

Question 20

Salt Removing Vegetation

Answer 20

Planting saltbush, barley, or oats can remove salts from the soil

Question 21

Road Salt Alternative

Answer 21

Beet juice and sand are effective alternatives to using road salt

Question 22

Ca2+ or Mg2+

Answer 22

This is the amount of calcium (Ca2+) or Magnesium (Mg2+) present in the soil, which can be determined by a chemical test for these elements.Problem: too little stunts growth. Too much is toxic. Solution: Add lime to increase the soil’s pH, making soil less acidic and more alkaline and increase the cations present in the soil (Ca2+ and Mg2+)

Question 23

N (Nitrogen)

Answer 23

This is the amount of nitrogen (N) present in the soil, which can be determined by a chemical test for this elements. Problem: too little stunts growth. Too much is toxic. Solution: Legumes — beans, peas and non-edible relatives such as clovers — convert atmospheric nitrogen (N2) into ammonium nitrogen (NH4), which they release into the soil.

Question 24

Soil pH

Answer 24

This is a measure of the hydrogen ions present in the soil. The amount of hydrogen ions present in the soil will determine the soil’s acidity or alkalinity. This can be determined by a chemical test. Adding lime/limestone or gypsum/green sand to neutralize the pH

Question 25

Green Revolution

Answer 25

A shift in agricultural practices in the twentieth century that included new management techniques, mechanization, fertilization, irrigation, and improved crop varieties, and that resulted in increased food output.

Question 26

Waterlogging

Answer 26

A form of soil degradation that occurs when soil remains under water for prolonged periods impairing growth because roots cannot get oxygen.

Question 27

Monocropping

Answer 27

An agricultural method that utilizes large plantings of a single species or variety to increase efficiency.

Question 28

Pesticide Treadmill

Answer 28

Over time, pest populations evolve resistance to pesticides, which requires farmers to use higher doses or to develop new pesticides. Pesticide use → evolutionary pressure → more resistance → more pesticide use.

Question 29

Composting

Answer 29

Creation of organic matter (humus) by decomposition under controlled conditions to produce an organic-rich material that enhances soil structure, cation exchange capacity, and fertility.

Question 30

Physical Pest Control (IPM)

Answer 30

Mechanical and temperature control of weeds and seed banks. Tilling can disrupt weed growth, but increases erosion. Mulching can suppress weeds and repel insect pests. Solarization and burning can heat kill pests, especially weeds.

Question 31

Furrow irrigation

Answer 31

A form of irrigation where the farmer digs trenches, or furrows, along the crop rows and fills them with water

Question 32

Flood irrigation

Answer 32

A form of irrigation where an entire field is flooded with water

Question 33

Spray irrigation

Answer 33

A form of irrigation where water is pumped into an apparatus that contains a series of spray nozzles

Question 34

Drip irrigation

Answer 34

A form of irrigation where a slowly dripping hose on the ground or buried beneath the soil delivers water directly to the plant roots