ENVIRON 111 Exam 3

LECTURE 13:

What is an environmental stressor?
1. An environmental stressor is a variable which exceeds its range of normal variation, affecting species, biological communities, or ecosystems. Ecological indicators help establish a stressor —> response realtiosnhip
2. Sources can include human activity
What is nutrient runoff? How does it threaten the Great Lakes?
1. Nutrient runoff is the process where excess nutrients, primarily nitrogen and phosphorus, are carried into bodies of water through surface runoff– often due to human activities like agriculture and urban development
What is a hypoxic or dead zone? How does it form? Why is it present in Lake Erie?
1. A hpoxic zone (dead zone) is an area in a water body where low levels of dissolved oxygen make it unsuitable for most aquatic life
2. Zones form when excess nutrients like phosphorus and nitrogen enter the water, causing algal blooms– when the algae die and sink to the bottom, they decompose, consuming large amounts of oxygen in the process, leading to hypoxia
3. It is present in Lake Erie due to heavy runoff from surroudning watershed, the lake’s depth, and stratification of the water column, which prevent oxygen from mixing from the surface to the bottom
What is the danger of using road salt for the Great Lakes?
1. Road salt leads to increased salinity of the water, which can be toxic to freshwater organisms, disrupt organisms, and even alter lake chemistry. It also contaminates groundwater and drinking water sources
What is the danger of toxic chemicals getting washed into the Great Lakes?
1. Toxic chemicals can impact human health, wildlife, and overal ecosystem by accumulating in humans and in fish. Thye can bioaccumulate and biomagnify
What can we learn from what happened in the Cuyahoga river in the ‘50s and ‘60s?
1. The fire served as a stark symbol of industrial pollution and environmental neglect
2. The pollution, which included industrial waste and sewage, had been ongoing for decades, yet the river’s condition was only brought to national attention by the dramatic fire.
What is the significance of a longer or shorter residence time for lakes?
1. Longer residence times can lead to increased nutrient and pollutant accumulation, potentially causing water quality issues like eutrophication
2. Shorter residence times promote faster flushing and better water quality
3. Residence times refer to the length of time that introduced substances, like pollutants or excess nutrients, remain in the lake and potentially build up
What is the issue with plastic in the Great Lakes?
1. The issue with plastic in the great lakes is primarily due to its breakdown into microplastics, which contaminate the water supply, harm wildlife, and pose potential health risks to humans
What are microbeads? Why are they detrimental to fish and potentially human health?
1. Micro beads are tiny plastic particles that are used as exfoliants in personal care products like soaps and face washes
2. They are detrimental to fish and by extension human health as they can be digested by aquatic life, absorbing toxins and entering the food chain
Why are invasive species dangerous for the Great Lakes? Is it something we should worry about today?
1. Invasive species are a serious threat to the Great Lakes ecosystem because they disrupt the balance of the environment, outcompete native species, and can even lead to extinction of native plants and animals
2. It is something to worry about today as they species continue to spread and cause significant ecological damage
How many invasive species are present in the Great Lakes today?
1. There are currently an estimated 64 species that are considered invasive.
Why is coastal development potentially hazardous for the Great Lakes?
1. Coastal development in the Great Lakes region can be hazardous due to increased flooding erosion, and water contamination
Is fishing important in the Great Lakes?
1. Yes, fishing is very important to the Great Lakes region, both commercially and recreationally. The great lakes fishery is valued at over $7 billion annually and supports over 750000 jobs
Is overfishing a problem in the Great Lakes?
1. Yes, overfishing is a significant problem in the Great Lakes, particularly affecting certain fish populations. It has led to declines in some fish species and altered the Great Lakes ecosystem.
Is water withdrawal an issue in the Great Lakes?
1. Yes, water withdrawal is a significant issue in the Great Lakes region, primarily due to the potential for depleting the lakes’ water levels and impacting the health of the ecosystem
2. Water withdrawals refer to the total amount of water removed from a source, like a river, lake, or aquifer, for various reasons– includes water taken for public supply, irrigation, industrial processes, and cooling electric power plants
How is water used in the Great Lakes basin?
1. Water is utilized in the Great Lakes for public water supply, industrial use, thermoelectric power generation, and agriculture.
2. It is also crucial for ecosystems, supporting streams, lakes, and wetlands
How has climate change affected the Great Lakes?
1. Climate change impacts the Great Lakes by leading to rising temperatures, alterest lake levels, decreased ice cover, and increased risk of extreme weather events.
How is the surface water warming trend of the Great Lakes? Which of the lakes has warmed more rapidly?
1. The Great Lakes are experiencing a significant warming trend, with Lake Superior, warming the most rapidly among them
2. Its surface water temperatures have increased at a much faster rate compared to the other Great Lakes and even global average temperatures.
How has evaporation changed in the Great Lakes over the last few decades?
1. Evaporation rates in the GL have generally increased over the last few decades, esp. In the summer due to rising temperatures and reduced ice cover
2. This trend has contributed to lower water levels in the lakes, with some lakes experiencing record highs and lows
How have the lake levels changed in the Great Lakes over the last few decades?
1. The GL water levels have generally fluctuated, w/ periods of decline followed by rises and then declines again
2. It has exhibited a range exceeding 2 meters
How has ice coverage changed on the Great Lakes? Which of the lakes has been losing more ice?
1. Great Lakes ice coverage has been decreasing across all five lakes since the start of record keeping 1973
2. Decrease is not uniform, some lakes have experienced more significant losses than others– lake superior, Huron St. Clair, and Erie have experiences the most substantial declines in Ice cover

LECTURE 14:

Is groundwater an important water source?
1. Yes, groundwater is a very important water source as it provides drinking water for about half of the US population and supports agriculture
What factors determine how much water will become groundwater?
1. Factors include:
  1. Soil and rock permeability- water can infiltrate more easily through porous and permeable materials lille sand and gravel
  2. Slope of the land: flatter land= more water can soak, ,steep slopes= runoff
2. Vegetation: plants slow down water flow and inc. infiltration
3. Rainfall intensity and duration: light, steady rain allows more infiltration than heavy downpours that cause runoff
4. Land use- urban areas w/ lots of pavement reduce infiltration, while natural areas increase it
What is the water table?
1. The water table is the upper level of the groundwater zone where the soil o rock is fully saturated with water– separates the unsaturated zone above (where pores contain air and water) from the saturated zone below.
What are porosity and permeability? Why is their significance?
1. Porosity: the amount of empty space (pores) in soil or rock that can hold water
2. Permeability: how easily water can flow through pores
3. Significance lies in how they affect groundwater movement– high porosity and permeability mean more water can be stored and transported underground, which is crucial for wells, aquifers, and water supply
What are aquitards and aquifers?
1. Aquifers are underground layers of rock or sediment that hold and transmit groundwater easily– like sand or gravel
2. Aquitards: layers that store water but don’t let it flow easily– like clay or dense rock
3. Aquifers are important for water supply while aquitards slow down or block water movement, helping confine and protect aquifers
How and why does the water table move?
1. The water table moves up or down depending on factors like rainfall, snowmelt, drought, and human water use
2. It rises when more water infiltrates the ground (like heavy rain) and falls during dry periods or when too much groundwater is pumped out
How does groundwater move?
1. Groundwater moves slowly through the pores and cracks in soil and rock, flowing from areas of high pressure to low pressure– usually down hill
2. Its speed and direction depend on the slope of the water table and the permeability of underground materials
What affects the depth of the water table?
1. Affected by:
  1. Climate: more rain can raise it, dry conditions lower it
  2. topography : usually deeper in hills and shallower in valleys
  3. Season: rises in wet seasons and drops in dry ones
  4. Human activity: pumping groundwater can lower it, while recharge efforts can raise it
How does the recharge rate affect the depth of the water table?
1. The recharge rate directly affects the depth of the water table
2. If recharge (the process of water replenishing the groundwater supply) is faster than groundwater extraction, the water table stays high or even rises
3. If recharge is slower than extraction or evaporation, the water table will drop
4. High recharge rates= shallower water table, low rates= deepen water table
What is the main use of groundwater in the US?
1. Irrigation- supporting agriculture
2. Also provides portion of drinking water + industrial processes
Is groundwater important in Michigan?
1. Yes very important:
  1. Drinking water
  2. Agricultural industrial uses
  3. Aquifers
  4. Environmental + health concerns
Is groundwater a renewable resource?
1. Groundwater is considered a renewable resource but rate of renewal depends on factors like:
  1. Recharge rate (how quickly water replenishes underground)
  2. Extraction levels
2. While it is renewable, needs to managed to maintain availability
What is land subsidence? How is it related to groundwater?
1. Land subsidence: sinking or lowering of the ground surface, often caused by the excessive withdrawal of groundwater– when too much groundwater is pumped from aquifers, the soil and rock layers above can compact, leading to a drop in the land surface
2. Happens because the water that once filled the pores in the soil is no longer there to support the weight of overlying materials
What is overpumping? How does it affect groundwater?
1. Overpumping refers to the extraction of groundwater at rate than it can naturally recharge
2. Leads to:
  1. Depletion of groundwater supplies
  2. Land subsidence
  3. Reduced water quality
Is groundwater a stressed resource?
1. Yes, groundwater is often considered a stressed resources in many areas, esp, where it is being overused or depleted faster than it can naturally recharge
2. Factors contributing to groundwater stress:
  1. Overpumping
  2. Pollution
  3. Climate change
What is groundwater depletion? Where does it happen in the US?
1. Groundwater depletion is the long term decline in groundwater levels due to excessive pumping, often faster than the natural recharge rate
2. Depletion occurs in:
  1. California’s Central Valley
  2. The High plains/Ogallala Aquifer
  3. Arizona and Neveada
What are saline intrusions?
1. Saline intrusions (saltwater intrusion)- occur when saltwater moves into freshwater aquifers, usually near coastal areas
2. Happens when groundwater levels drop too low (overpumping usually) and reduces the pressure that keeps seawater out– wells become contaminated w/ saltwater making water unsafe for drinking or irrigation
How is road salt affecting groundwater?
1. Road salt can seep into the ground and contaminate groundwater by increasing its chloride levels- -happens when snow and ice melt, carrying salt into the soil and eventually aquifers
2. High chloride concentrations can harm drinking water quality, damage infrastructure, and negatively impact plants and aquatic life
How does groundwater pollution affect the quality of groundwater?
1. Groundwater pollution lowers the quality of groundwater by introducing harmful substances like bacteria, heavy metals, or nitrates
2. This contamination makes water unsafe to drink, can harm ecosystems, and be very difficult and expensive to clean up
What is happening in Ann Arbor in terms of groundwater pollution?
1. In Ann Arbor groundwater pollution is a significant environmental concern due to a long standing contamination issue involving 1,4 dioxane, a synthetic industrial chemical and probable human carcinogen

LECTURE 15:

How has sea surface temperature been changing in the last century?
1. Over the last century, sea surface temperatures have ben rising, esp. Since the 1970s– avg: about 1.5f
2. SSts contribute to more intense hurricanes, coral bleaching, and changes in ocean currents and ecosystems
Where do we see most of the warming in the ocean?
1. Most of the warming in the ocean occurs in the upper 700 meters of the water column, esp. In the top 100 meters, where sunlight penetrates and heat exchange with the atmosphere is strongest
2. Esp. noticeable in the tropical and subtropical regions, and in areas like the North Atlantic and western Pacific
How does that relate to changes in primary productivity?
1. Warming of the ocean affects primary productivity– the rate at which phytoplankton produce energy through photosynthesis– several ways:
  1. Increased stratification
  2. Fewer nutrients
  3. Regional differences
What is the ocean warming trend of the last few years? Why was 2016 so warm?
1. Ocean temperatures have hit records high in recent years, w/ 20203-2024 surpassing 2016 levels due to ongoing climate change
2. 2016 was especially warm because of strong El Nino combined with long term global warming
What is El Nino?
1. El nino is a natural climate pattern where warm water builds up in the central and eastern pacific ocean, disrupting normal weather patterns
2. It can cause drier conditions in some areas (like Australia) and heavier rainfall or storms in others (like the Americas)
How does water temperature change along the equatorial Pacific during an El Nino?
1. During El Nino, sea surface temperatures along the central and easten equatorial Pacific become much warmer than normal
2. This warming reduces the usual east-to west trade winds and weakens upwelling of cold, nutrient-rich water near South America, disrupting marine ecosystems and global weather patterns
How does El Nino affect weather in the US?
1. El nino affects weather by shifting the jet stream and storm patterns
  1. Southern US: wetter and cooler than normal winters (more storms and rain)
  2. Northern US: warmer and drier winters than usual
What is coral bleaching and how is it related to El Nino?
1. Coral bleaching happens when coral expel the algae that live in their tissues due to stress from unusually warm water– turning them white and weakening them
2. During el nino, ocean temperatures rise, especially in the Pacific, increasing the chances of mass coral bleaching events
How is sea level increasing today? How is that connected to the warming?
1. Sea levels are rising due to thermal expansion (water expanding as it warms) and melting ice sheets and glaciers
2. As global temperatures rise, the warming of the oceans cause water to expand and the melting of polar ice adds more water to the oceans, both contributing to higher sea levels
3. Linked to global warming driven by human activities, primarily through GHG emissions
Is the US going to be affect by sea level increase? Where?
1. Yes the US will be significantly affected by sea level rise, particularly in coastal areas
2. Most vulnerable areas include:
  1. Florida
  2. Lousiana
  3. Northeast and Mid atlantic
  4. CA
What kind of issues is sea level rise already causing and will cause more and more in the future?
1. Sea level rise is already causing several issues and will continue to worsen in the future
  1. Flooding
  2. Erosion
  3. Saltwater intrusion
  4. Displacement
  5. Storm surge
Which are the countries most affected by sea level rise?
1. Bangladesh
2. Maldives
3. Vietnam
4. Netherlands
5. Kiribati
6. Tuvalu
What are storm surges?
1. Storm surges are temporary rises in sea level caused by strong winds and low pressure from tropical storms or hurricanes
2. As the storm approaches the coast, winds push water toward the shore, causing abnormally high water levels that can result in flooding
How does sea level rise contribute to the dangers related to storm surges?
1. Higher baseline sea levels
2. Increased flooding
3. More frequent and intense storm surges
What are tropical cyclones and hurricanes?
1. Tropical cyclones and hurricanes are powerful storm systems that form over warm ocean waters
  1. Tropical cyclones– general term for large storm systems w/ stong winds and heavy rain
    1. Hurricanes
    2. Typhoons
    3. Cyclones
  2. Hurricanes
How and where do they form?
1. Tropical cyclones (hurricanes) form over warm ocean water waters near the equator, where water is at least 80 F
2. Warm air rises, creating a low-pressure system that spins due to Coriolis effect
3. Where they form:
  1. Atlantic ocean
  2. Pacific ocean
  3. Indian ocean
Why do they all move along similar paths?
1. Tropical cyclones follow similar paths due to global wind paters and the coriolis effect
  1. Trade winds push storms from east to west across the tropics
  2. As they move, high pressure systems steer them toward the poles and coriolis effect causes the storm to curve
What is the correlation between hurricanes and warm ocean water?
1. Hurricanes fueled by warm ocean water because it provides the heat and moisture to power the storm
  1. Warm water causes the air above it to rise– creates a low pressure system
  2. Rising air draws in more moisture, which condenses to release latent heat, intensifying the storm

What is the Saffir-Simpson scale?
1. Five level system used to measure the intensity of hurricanes based on sustained wind speeds
2. 1-5 category
As CO2 increases in the atmosphere, how are CO2 concentrations changing in the ocean and how is ocean pH changing?
1. As CO2 levels in the atmosphere rise, more CO2 is absorbed by the oceans, leading to
  1. Increased CO2 concentrations in the ocean, particularly in surface waters
  2. This results in the formation of carbonic acid, which lowers ocean pH– ocean acidification
  3. As ocean pH decreases, it becomes more acific, which can harm marine life, esp. w/ calcium carbonate shells or skeltons
How does CO2 enter the ocean?
1. Co2 enters the ocean through gas exchange– when atmospheric CO2 comes into contact w. Ocean surface, some dissolves into the water– influenced by factors like wind and waves
2. Once dissolved, CO2 reacts w/ water to form carbonic acid, whcih further dissociates into bicarbonate and hydrogen ions
How important is the ocean and a C sink?
1. The ocean is a crucial carbon sink– absorbs about 25-30% of human made CO2 emissions
Why are some parts of the ocean mainly acting as C sinks and others as sources?
1. Temperature– cold waters absorb more CO2 than warm waters
2. Biological activity– areas w/ high phytoplankton
3. Ocean circulation
4. Coast vs. deep ocean
How would changes in primary productivity due to ocean warming affect the effectiveness of the ocean as a C sink?
1. Decreasing productivity
2. Stratification
3. Ecosystem disruptions
What happens to CO2 as it dissolves in the ocean? What are all the species of dissolved inorganic carbon (DIC) formed as CO2 dissolves in the water?
1. Carbonic acid
2. Bicarbonate
3. Carbonate
How does that affect the ocean pH?
1. As CO2 dissolves in the ocean, it forms carbonic acid, which dissociates into bicarbonate and hydrogen
  1. The more co2 that dissolves, the most H+ is produced, which causes ocean acidification
  2. This pH shift can harm marine life, esp. Organisms that rely on calcium carbonate
What are acids and pH?
1. Acids are substances that release hydrogen ions
2. pH is a scale (0-14) that measures how acidic or basic a solution
How does pH control what main species of inorganic carbon will be present in the water? Why is this important?
1. pH controls which form dissolved inorganic carbon DIC dominates
  1. Low pH (acidic)-- cor CO2 and carbonic
  2. Neutral pH– more bicarbonate
  3. High pH (basic)-- more carbonate
What is the carbonate buffering system? How does it work?
1. Carbonate buffering system helps keep ocean pH stable by balancing CO2, bicarbonate, carbonate
  1. When pH drops (more pacific), carbonate ions react w/ H+ to from bicarbonate, removing H+ and raising pH
  2. When pH rises (less acidic), bicarbonate can release h+ to lower the pH
Is pH changing in the surface waters? Why? What are the predictions?
1. Yes pH is decreasing in surface waters– ocean acidification
2. More CO2 from the atmosphere is dissolving into the ocean, forming carbonic acid and releasing H+, which lower pH
3. Predictions: if CO2 emissions continue, surface ocean pH could drop by .3-.4 units by 2100, making the ocean more pacific than its been
Where in the water column do we see an increase in dissolved CO2? Why?
1. We can see an increase in dissolved CO2 in deeper waters of the ocean
What are the possible consequences of this?
1. Lower pH (more acidic) conditions– affects deep-sea ecosystems
2. Reduces carbonate availability, makes it harder for deep-sea organism to build shells
3. Disruption of carbon storage
What is ocean acidification?
1. The process by which the ocean becomes more acidic due to absorbing excess C02 from the atmosphere
2. This lowers the oceans pH, reduces carbonate ions, and threatens marine life like corals, shellfish, and plankton that need carbonate to build their skeletons and shells
How will ocean acidification affect the stability of CaCO3 in the ocean?
1. Will make calcium carbonate less stable in the ocean
2. As pH drops, carbonate ions become less available, making it harder for organisms to form and maintain shells and skeletons
3. CaCO3 can also dissolve more easily, weakening existing structures like coral reefs
How is the aragonite saturation changing already in the ocean today? What are possible consequences?
1. Aragonite saturation is decreasing, weakening shells and coral, disrupting ecosystems

LECTURE 16:

What is nonpoint-source pollution?
1. Pollution that comes from many diffuse sources, like runoff from farms, roads, or lawns, rather than a single, identifiable source like a factory pipe
How does oil make it into the ocean?
1. Enters the ocean through spills, runoff from land, leaks from ships, natural seeps
Why is oil bad for the ocean ecosystem?
1. Harms marine life by coating animals, damaging their insulation or buoyancy, and poisoning them through ingestion or absorption
2. Also disrupts the food chains and degrades habits like coral reefs and shorelines
How large was the 2010 Gulf of Mexico BP oil spill?
1. The oil spill released approx. 4.9 million barrels (about 205 million gallons) of oil into the Gulf of Mexic0 over 87 days– largest marine spill in history
2. The spill affected about 680000 sq. feet
What kind of impact did (and does) it have on sea life?
1. The BP spill caused massive death and injury to sea life– fish, dolphins, sea turtles, and seabirds– it damaged reproductive systems, caused birth defects, and led to long-term contamination of habits, disrupting ecosystems for years
How did the oil move through the water column?
1. Moved through the water column by forming plumes– clouds of tiny oil droplets– due to high-pressure leak at the seafloor
2. dispersants also broke the oil into smaller droplets, allowing it to mix into deeper water layers instead of just floating on the surface
What is marine debris? Why is it dangerous to wildlife?
1. Human made trash-like plastic, fishing gear, and other waste, that ends up in oceans or waterways
2. Dangerous because animals can get entangled, mistake it for food, and surface injury, starvation, or death
What is the Pacific garbage patch? Why is it found where it is?
1. Massive area of concentrated marine debris, mostly plastic, floating in the north pacific ocean
2. Found because ocean currents, especially the north pacific gyre, trap and accumulate debris over time
What products end up as garbage in the ocean?
1. Common products that end up in the ocean garbage include plastic bags, bottles, straws, food wrappers, fishing nets, microplastics from cosmetics or clothing, and styrofoam containers
How long are these products going to survive in the ocean before they decompose?
1. These products can take decades to decompose
2. Ex: water bottles can take up to 450 years, and fishing nets can last over 600 years in the ocean
How much plastic and debris ends up in the ocean?
1. Its estimated that about 8 million tons of plastic enter the ocean each year
2. Contributed to millions of tons of debris, impacting marine ecosystems globally
What is the importance of ocean currents in controlling where the garbage ends up in the ocean?
1. Ocean currents play a crucial role in carrying debris across vast distances into areas like gyres, where currents converge and trap debris, creating patches like the Pacific garbage patch
What is primary and secondary microplastics?
1. Primary: tiny plastics made small on purpose, like microbeads in cosmetics
2. Secondary: larger plastics breaign down over time due to sunlight waves, or weathering
Where is microplastic coming from?
1. Micorplastics come from a source like synthetic clothing fibers, car tire wear, broken-down plastic waste, personal care products w/ microbeads, and industrial processes
Why are we concerned about it?
1. Microplastics are eaten by marine life, entering the food chain and potentially affecting human health
2. They can carry toxic chemicals, disrupt ecosystems, and are nearly impossible to remove once in the environment
What are persistent organic pollutants? Why are they dangerous to us?
1. POPs are toxic chemicals that resist breakdown and accumulate in the environment and living organisms
2. Theyre dangerous because they can cause cancer, hormone disruption, immune issues, and birth defects, even at low exposure levels
Why is mercury dangerous and how does it get in the ocean and in fish?
1. Can cause damage to the brain, nervous system, and organs, especially in young children and fetuses
2. Goes into the ocean through industrial pollution (like coal burning) where microbes convert it into toxic methylmercury that accumulates in fish and moves up the food chain
Which fish has more mercury and which has less? Why?
1. Long-lived fish like shark, swordfish, king mackerel, and tuna have more mercury bc they eat smaller fish and accumulate it over time (biomagnification)
2. Smaller fish like salmon, sardines, tilapia, and anchovies have less mercury bc they’re lower on the food chain
How much canned tuna can you safely eat?
1. FDA recommends 2-3 servings of light canned tuna per week
Why is runoff potentially dangerous for the ocean ecosystem?
1. Runoff can carry pollutants like fertilizers, pesticides, oil, and trash into the ocean
2. These substances can harm marine life, fuel algal blooms, deplete oxygen, and disrupt entire ecosystems
What are the dangers associated with nutrient enrichment in the ocean?
1. Nutrient enrichment (mainly from P and N) can cause algal blooms– these blooms block sunlight, reduce oxygen levels (creating dead zones), and kill marine life
What is eutrophication?
1. The excessive buildup of nutrients in water, leading to dense algal growth
2. When the algal die and decompose, it depletes oxugen, creating dead zones where marine life cant survive
What is the dead zone in the Gulf of Mexico?
1. Large area of a low oxygen (hypoxia) that forms every summer, due to nutrient pollutant from MI river basin
2. About 3058 sq miles and size of delaware
3. Disrupts marine ecosystems and poses sugnficant challenges to the gulfs fishing and tourism industry
How does it form?
1. Forms from excess nitrogen and phosphorus from ag. Runoff, wastewater, and other sources fuel massive algal blooms

LECTURE 17:

What is overfishing?
1. When fish are caught from the ocean faster than they can reproduce and replenish their populations
2. This leads to a decline in fish stocks, disrupts marine ecosystems, and can threaten the livelihoods of communities
How many fish species are currently threatened by overfishing?
1. Over 1000
What is the status of the populations of predatory fish today?
1. Lagre predatory fish have declined by over 90% due to overfishing
2. They are vulnerable because they reproduce slowly and are heavily targeted by fisheries
3. This decline disrupts marine ecosystems by unbalancing the food web
4. Conservation efforts exist but many species are still at risk
Why do we fish?
1. Income, recreation, cultural traditions, and to support global economies and livelihoods
What are some main causes of overfishing?
1. Industrial scale fishing, poor regulation, illegal fishing, high seafood demand, and lack of enforcement in international waters
What are different kinds of overfishing?
1. Growth overfishing: catching fish before they reach full size
2. Recruitment overfishing: removing so many adults that not enough young are born
3. Ecosystem overfishing: disrupting the food chain by removing key species
4. Economic overfishing when the cost of fishing outweighs the economic benefits
What is the status of fishing stocks today?
1. About one third of global stocks are overexploited, with many others fully exploited– means they are being caught at their maximum sustainable levels
2. Some fish populations, particularly those of large predators, have seen drastic declines due to overfishing
3. Efforts to rebuild stocks through sustainable fishing practices are ongoing but face significant challenges
Describe what is happening to the cod, Bluefin tuna, and Atlantic salmon.
1. Cod: drastically declines due to overfishing, with some atlantic cod stocks nearly collapsing
2. Bluefin tuna: once abundant, now critically endangered due to overfising for high value markets, esp. In sushi and sashimi
3. Atlantic salmon: populations are also struggling, with so many facing decline due to habitat loss, overfishing and climate change, despite efforts to protect them through fisheries management and hatchery programs
What are examples of destructive fishing methods that we discussed in class?
1. Bottom trawling: dragging heavy nets across the ocean floor, famaging ecosystems and destroying habitats
2. Dynamite fishing: using explosives to stun or kill fish, causing severe harm to marine life and habitats
3. Poison fishing: using toxic substances to kill fish, which harm entire ecosystems
4. Bycatch: the capture of unintended species, including endangered ones, leading to population declines
What does it mean to ‘fish down the food web’?
1. Refers to the practice of targeting smaller, lower-level species as larger, higher-level predators become overfished, disrupting the natural food chain and ecosystem imbalance
What is happening to tunas today?
1. Tuna populations, especially Bluefin tuna, are critically endangered due to overfishing driven by high demand for sushi and sashimi
2. Stocks have drastically declines and despite international conservation efforts, illegal fishing and bad regulation continue to threaten their recovery
Is overfishing happening in the US?
1. Yes it is occurring, but progress has been made over the years
What happened to the red snapper?
1. Has recovered significantly from overfishing due to management measures like reduced bycatch and rebuilding plans
2. While stock has improved, it still faces challenges, such as illegal fishing and a young age structure, requiring ongoing conservation efforts
Is overfishing a widespread problem worldwide?
1. Yes, overfishing is a widespread global problem, w/ about one third of fish stocks being overexploited and many other fully exploited, threatening marine biodiversity and food security
Is fishery collapse a reality today?
1. Yes, fishery collapse is a reality today, with several fish populations, like atlantic cod and bluefin tuna, having collapsed or drastically declined due to overfishing
What is by-catch?
1. The unintentional catch of other organisms/animals when targeting one specific one
How can we prevent overfishing?
1. We can implement stricter fishing regulations, enforce sustainable catch limits, reduce bycatch, protect marine habitats, promite responsible fishing practices, and invest in ecosystem restoration efforts
What are some of the solutions?
1. Establishing marine protected areas
2. Implementing catch limits
3. Promoting sustainable fishing practices
4. Improving enforcement
5. Restoring habitats
6. Supporting fishery management programs
How are US fish populations doing?
1. Have improved significantly– 94% of stocks not subject to overfishing and 50 stocks successfully rebuilt
What is the difference between fish on the overfishing or overfished list?
1. Fish on overfishing list are being caught at rates that exceed sustainable levels, while fish on the overfished list have populations that are too low to maintain long term sustainability
What is a standing stock?
1. Refers to total biomass or population of a particular species in a specific area at a give time, representing the amount of fish or other organisms available in that ecosystem
What is the maximum sustainable yield?
1. The largest amount of fish species that can be caught without compromising its ability to replenish its population over time, ensuring long term sustainability
Who decides how much fish we can catch?
1. Typically set by government agencies (liek NOAA) and international orgs, based on scientific assessment of fish populations, ecosystem health, adn sustainability
Can fish recover from overfishing? How?
1. Yes fish can recover from overfishing through sustainable management practices such as setting catch limits, establishing marine protected areas, reducing bycatch, and allowing time for populations to regenerate
What is the Marine Stewardship Council?

LECTURE 18:

What is aquaculture?
1. Aquaculture is the farming of fish, shellfish, and seaweed in water for food or other products
Is aquaculture only happening in the ocean?
1. No, aquaculture happens in both freshwater and saltwater
2. It can take place in oceans, rivers, lakes, or man-made tanks and ponds
How important is aquaculture today in terms of fish production? Why?
1. Aquaculture is very important– it supplies over half of the world’s fish for human consumption
2. It helps meet the growing demand for seafood as wild fish stocks decline due to overfishing and environmental pressure
How is aquaculture production predicted to change in the future?
1. Aquaculture production is expected to grow significantly in the coming year to meet rising demand for seafood and support food security
Describe the geography of aquaculture.
1. Aquaculture is common worldwide, especially in Asia (China, India, Vietnam)
2. Others: noway, chile, and US
How important is fishing for the economies of developing countries?
1. Fishing is very important for many developing countries
2. Provides jobs, foods, and income– esp. In coastal communities and supports exports and trades
How important is fish as a source of proteins in developing countries?
1. Fish is crucial protein source in developing countries
2. Provides up to 50% or more of animal protein in many coastal and island region
What are some of the commonly aquatic organisms farmed today?
1. Commonly farmed aquatic include fish (salmon, tilapia, and catfish) shellfish
What are some of the commonly aquatic organisms farmed today in the US?
1. Catfish, rainbow trout, atlantic salmon, tilapia
What are aquaculture open systems and how do they work?
1. Environments where aquatic organisms are farmed in natural water bodies, like oceans, lakes, or rivers
2. These systems allow water to flow freely in and out, providing natural conditions
What are aquaculture semi-closed systems and how do they work?
1. Farming environments that combine natural water flow with controlled conditions
2. Water circulates in and out of contained area, like ponds or tanks, but it is filtered and treated to maintain water quality
3. These systems reduce pollution and disease risks compared to open systems
What are aquaculture closed systems and how do they work?
1. Fully contained environments where water is continuously recycled and treated within the system
2. RAS use filters, aeratos, and biological treatments to maintain water quality
What are some of the possible environmental effects of aquaculture?
1. Water pollution
2. Habitat destruction
3. Spread of diseases
4. Escape of farmed species
5. Overfishing of feed sources
What is the issue with farming carnivorous fish?
1. Farming carnivorous fish, like salmon, can be problematic bc they require fishmeal and fish oil made from wild-caught, which contributes to overfishing
Is farmed and wild caught fish the same nutritionally?
1. Farmed and wild caught are similar in many nutritional aspects, such as protein and omega-3 fatty acids, but farmed fish have higher fat content due to their diet
2. Farmred fish, especially those like salmon, may also contain more omega-6 fatty acids
How is sustainable aquaculture?
1. Aims to minimize environmental impact while providing seafood efficiently– focuses on practices like reducing waste, using eco-friendly feed, conserving water, and preventing overfishing
2. Technologies like recirculating systems and integrated multitopic aquaculture
Why is shellfish farming considered sustainable?
1. Considered sustainable bc shellfish filter and clean water as they grow, improving water quality
2. They dont require feed or chemicals, and their farming has minimal environmental impact– they also don't contribute to overfishing, as they are farmed form the oceans natural resources
What are some of the advantages of farming fish versus other animals?
1. Efficiency– fish convert feed into body mass more efficiently than land animals
2. Space– require less space
3. Lower GHG emissions
4. Faster growth
5. Less water usage

LECTURE 19:

What are some of the successes of conventional agriculture?
1. Boosted food production, reduced hunger, and increased crop yields through fertilizers, pesticides, and mechanization
2. Has also made food more affordable and widely available
What are some of the problems of conventional agriculture?
1. Food waste- we can produce a lot of food for everyone (more food than demand for entire world, but so much food is wasted for different reasons- leading to hunger)
What is food waste? Why is it a problem?
1. Edible food that is thrown away or spoiled before being eaten
2. Problem bc it wastes resources like water, energy, and labor, contributed to GHG emissions and adds pressure to produce more food unnecessary
What are monocultures?
1. Large scale plantings of a single crop over an area
2. Efficient but risky– reducing biodiversity, depleting soil nutrients, and increasing vulnerability to pests and diseases
Why are pesticides dangerous?
1. Pesticides can harm non-target species (like bees and birds), contaminate water and soil, and pose health risks to humans, including cancer, horome disruption, and neurological issues
Why is the use of fertilizers dangerous?
1. Can lead to nutrient runoff, causing water pollution and eutrophication
2. Also contribute to GHG emissions and can degrade soil health over time
What is sustainable agriculture?
1. Farming that meets current food needs w/out harming environment for future generations– focuses on conserving resources, maintaining soil health, and supporting biodiversity
How does the 3-legged stool of sustainability apply to agriculture?
1. Environmental, economic, and social— applies to agriculture by promoting farming that protects the planet, is financially viable for farmers, and supports communities through fair labor and food access
How can agriculture be economically sustainable?
1. It can be economically sustainable when farms are profitable long term, use resources efficiency, reduce input costs (like water or chemicals), and adapt to market changes w/out harming the environment or community
How can agriculture be environmentally sound?
1. It is environmentally sound when it conserves water, builds healthy soil, reduces chemical use, protects biodiversity, and limits pollution through practices like crop rotation, organic methods, and pest management
How can agriculture be socially sustainable?
1. It is socially sustainable when its supports fair labor, safe working conditions, access to nutritious food, community well being, and respects the rights and traditions of local population
How can we farm sustainably?
1. We can farm sustainably by using crop rotation, reducing chemical inputs, conserving water, protecting soil health, supporting local food systems, and integrating animals and plants in balanced ways
How are organic agriculture and sustainable agriculture different?
1. Organic farming excludes the use of synthetic inputs, such as synthetic fertilizers, pesticide, herbicides, and GMOS– sustainable agriculture does not
What is the range of the C footprint of different crops? How do production and post-production processes affect the C footprint of different crops (for example animal proteins vs veggies)?
1. Carbon footprints vary widely: veggies like lentils or potatoes have low footprints (around .2-.4 kg CO2) while animal proteins like beef are much higher ( around 27 kg CO2/kg).
2. Productions (like feed, land use, and methane from cows) has the biggest impact for animal products, while post production (like transport and refrigeration) matters more for perishable plant foods
Why can some crops, such as asparagus and tomatoes, have a high carbon footprint?
1. Crops like asparagus and tomatoes can have high carbon footprints due to factors like energy-intensive GHG production, long distance transportation, and high water usage
2. Growing them out of season or in non-native regions also adds to their environmental impact
What is the concept of food miles?
1. Food miles refer to the distance food travels from production to consumption– the longer the journey, the higher the carbon footprint, as transportation (esp. By air or truck) contributes to GHG emissions
Does it matter how the food gets to you? How it travels?
1. Yes, how food travels matter
2. Air transport has a much higher carbon footprint than shipping by sea or truck
3. Local sourcing, using rail or less energy intensive transport methods, reduces emissions and the overall environmental impact
Is local food always more sustainable? Why?
1. Local food is often more sustainable bc it reduces transportation emissions and supports local economies
2. It is not always more sustainable, farming methods, resource use, and seasonality play a key role
3. For ex: out of season local produce might require energy-intensive methods like GHG
What is the range of the water footprint of different crops?
1. Water footprint vary videly by crop:
  1. Low water crops( ex: oats or wheat) use around 1000-2000 liters of water/kg
  2. High water crops (ex: almonds, and rice) require 10000-15000 per kg– animals products, esp beef, have much higher water footprints with over 15000 liters/kg due to feed and water consumption for livestock
What are GMO crops? What are some of pros and cons about these foods?
1. Pros:
  1. Increased yields
  2. Reduced need for pesticides
  3. Enhanced nutritional content
2. Cons:
  1. Potential environmental risks (eg: gene flow to wild plants)
  2. Ethical concerns
  3. Possible health risks (though not proven, they remain a concern for some)
What is urban farming?
1. Urban farming is the practice of growing food in cities or urban areas, often in small spaces like rooftop, vacant lots, or community gardens
2. It helps reduce food miles, promote local food security, and can improve urban sustainability
What is community supported agriculture?
1. A system where consumers buy shares of a farms harvest in advance
2. Members get fresh, seasonal produce regularly, while farmers gain financial support and a direct relationship with their community
What is compost?
1. Compost is decomposed organic material– like food scraps, leaves, and yard waste– used to enrich soil
2. It improves soil health, reduces landfill waste, and helps plants grow w/out synthetic fertilizers