Ecol 1000 Exam 2 PDF

Lecture 9 Restoration Ecology Restoration Ecology: the science that deals with the repair of damaged or disturbed ecosystems Role of indicator species in restoration: ○ Wood storks gave ecologists an early warning that the Everglades ecosystem was in trouble...

Lecture 9 Restoration Ecology Restoration Ecology: the science that deals with the repair of damaged or disturbed ecosystems Role of indicator species in restoration: ○ Wood storks gave ecologists an early warning that the Everglades ecosystem was in trouble ○ When the U.S. Corps of Engineers evaluated the damage, they found that the size of the Everglades had been reduced by 50% since the late 1800s due to canalization of water, development, and associated reduced wetland habitat ○ Wood storks are monitored as a gauge of success in the restoration efforts The Comprehensive Everglades Restoration Plan The goal of CERP is to restore some water flow back to historic wetland areas through various methods, including the removal of more than 240 miles of canals ○ This will allow more freshwater to soak into the ground, benefitting both the ecosystems and the residents of South Florida 1- Get the water right ○ QQTD: Quality, Quantity, TIming, Distribution 2- Restore, Preserve, and Protect Natural Habitats and Species ○ Including increasing available habitat (water, allocation, land purchase), including habitat corridors (i.e. for panthers), and removing the harmful effects of invasive exotic species 3- Foster Compatibility of the Built and Natural Systems ○ The Everglades and people are “in it together” and will need to have room for agricultural land, flood control, and future changes ○ Future changes include climate change, sea level rise and population growth Endangered Species Endangered species in the Florida Everglades includes ○ Wood stork  ○ Wood rat ○ Florida Panther (there are only about 200 left; at least 11 were killed by vehicles in 2024) Habitat loss is the most significant factor in decline of panther populations Invasive Species Burmese Python (snake) Argentine tegu (lizard) Brazilian pepper (plant) Pace of Evolution and Extinction The pace of evolution and extinction is generally slow It is not constant or the same for all species as it is affected by a variety of factors: ○ Genetic diversity ○ Size of population ○ Reproductive rate (biotic potential) ○ Generation time (ex: bacteria reproduce quickly- antibiotic resistance) ○ Strength of the selective pressure Evolution: differences in the gene frequencies within a population from one generation to the next Extinction: the complete loss of a species from an area; may be local (gone from an area) or global (gone for good) Natural Selection and Evolution Individuals within a population are genetically different from one another. This results in differential survival due to selective pressure Genes: stretches of DNA, the hereditary material of cells,that each direct the production of a molecule, usually a protein and influence an individual’s traits Alleles: variants of genes that account for the diversity of traits seen in a population Selective pressure: a nonrandom influence that affects who survives or reproduces Evolutionary biology helps us understand the diversity of life on Earth and how populations change over time  Natural Selection: the process by which organisms best adapted to the environment (the fitter) survive to reproduce, leaving more offspring than less well-adapted individuals ○ It is the primary driving force of evolution ○ It is SLOW!!! When extinctions unfold over long periods of time, better-adapted species tend to replace their predecessors and the niche remains filled ○ Rapid extinction events may eliminate well-adapted species and break important community connections Lecture 10 Climate Change Weather: the meteorological conditions in a given place on a given day Climate: long-term patterns or trends of meteorological conditions Climate change: alteration in the long-term patterns and statistical averages of meteorological events Effects of climate change: ○ Hotter: rising temperatures around the planet, record high temperatures, more and longer heat waves ○ Changes in timing and location of seasons: earlier springs and later winters, extreme cold weather in some places, positional shifts in biomes ○ More saltwater, less freshwater: rising sea levels loss of crucial freshwater supplies ○ Stronger and less predictable storms: stronger storms on land, more predictable and variable weather Celcius → Fahrenheit ○ 2* C change to F; is a change of 3.6* F ○ 0 → 32 ○ 1 → 33.8 ○ 2 → 35.6 ○ 38 → 100.4 ○ 40 → 104 Evidence of climate change:  ○ A warming planet should see warmer average temperatures, melting ice on sea and land, rising sea levels, and precipitations changes ○ Most (more than 99%) recent peer-reviewed scientific papers conclude that the climate is now changing and that this change is in response to human activities ○ Uncertainty exists over the rate at which future changes and impacts will unfold, but the broad outline of consequences is not in dispute Give predictions that scientists make about the consequences of climate change: ○ Temperatures will rise ○ Weather patterns will change ○ Ice will melt ○ Sea levels will rise ○ There will be impacts on biodiversity Greenhouse Effects Greenhouse gasses: molecule in the atmosphere that absorb heat and reradiate it back to Earth ○ Examples: water vapor (H2O), carbon dioxide (CO2), methane, and nitrous oxide Greenhouse effect: the warming of the planet that results when heat is trapped by Earth’s atmosphere ○ Positive climate forcers ○ Adding more greenhouse gasses to the atmosphere contributes to an enhanced greenhouse effect that warms the planet Climate forcer: anything that alters the balance of incoming solar radiation relative to the amount of heat that escapes out into space ○ Climate forcers can be positive: they can increase warming ○ Climate forcers can be negative: they can decrease warming Which greenhouse gas makes the biggest contribution to global warming today? ○ Carbon dioxide Which greenhouse gas is the most “potent” in terms of warming potential? ○ Nitrous oxide Keeling Curve: the best data we have on “real time” atmospheric carbon dioxide measurements (1958-present)  ○ Other ways that “past climates” can be reconstructed: pollen, air bubbles in ice cores, tree growth rings, element isotopes, lake sediments) Other Factors that Affect Climate Greenhouse gasses are not the only climate forcers ○ Higher albedo (reflectivity of a surface) can have a cooling effect ○ Decreasing a surface’s albedo can increase warming, and this warming can escalate via positive feedback Albedo: the ability of a surface to reflect away solar radiation ○ The reflectivity of a surface: Light-colored surfaces (such as ice) have a high albedo because they reflect sunlight (reduce heat) Darker surfaces (such as asphalt) have low albedo because they absorb sunlight (increase heat) Positive feedback loop: changes caused by an initial event that then accentuate that original events ○ As surfaces with high albedo are replaced with low albedo surfaces, the planet continues to warms (this melts more ice, further reducing surfaces with high albedo) Negative feedback loop: changes caused by an initial event that trigger events that then reverse the response ○ ex) when warming leads to events that cause cooling As temperatures rise, glaciers will melt and form more water. Because water absorbs more heat than does ice, the region becomes warmer. This is an example of: ○ Positive feedback loop Current/Future Impacts of Climate Change Impacts: ○ Health and water scarcity ○ Agricultural effects Increase in pest outbreaks, agricultural productivity decline ○ Spread of disease Increasing frequency and range of insect-borne disease  ○ Biodiversity loss Wildlife population decline The negative impact of rising temps and acidification on ocean communities ○ Increased fire risk ex) Australia and the American West 2020 Increasing temperatures in inland cities ○ More extreme storms, coastal erosion and flooding Increasing health issues and property loss due to sea level rise and storm events Increase in the number of climate refugees Beyond weather, climate change has environment, economic, societal, and health consequences such as freshwater becoming increasingly scarce in some areas Lecture 11 Tyndall AFB Building standards are designed to withstand strong winds and storm surge, and also include energy efficient design, multiple uses, accessibility, etc Couples with a landscape master plan that uses native landscaping, green infrastructure, and walkability Coastal resilience ecosystem projects which include rebuilding sand dunes, oyster reefs, restoring salt marshes, seagrasses and even longleaf pine forests to block winds Installation resilience: has a definition in the US Code that allows DOD the authority to address climate change since it impacts the mission of DOD ○ 3 things that confer installation resilience: land conservation ecosystem restoration other nature-based solutions ○ 6 ecosystem services that the DOD considers: Flood resilience Water supply  Permafrost protection Carbon storage Recreation They also manage a lot of threatened and endangered species Climate Models Climate models: computer programs that allow scientists to make future climate projections by plugging in values for temperature, CO2 concentrations, global air circulation patterns, and so on 2016 Paris Agreement ○ 2016 Paris agreement replaced the Kyoto Agreement Allowed nations to set their own targets, with a goal of keeping warming “well below 2*C” above pre industrial levels, preferably capping warming at 1.5*C Most nations are not on track to meet their Paris pledges Political and social opposition have slowed the U.S. response Main threats to biodiversity today come from humans ○ Habitat destruction being the largest threat Responses to Climate Change Climate mitigation: efforts to minimize the extent or impact of climate change ○ Preventing further warming by addressing the causes of climate change ○ Includes attempts to seriously curb the amount of greenhouse gasses we are releasing and steps to remove CO2 from the air ○ Stop deforestation, use waste management practices, use sustainable and nuclear energy, purse carbon capture and sequestration Carbon taxes: governmental fees imposed on activities that release greenhouse gasses into the atmosphere Climate adaptation: efforts to help deal with existing or impending climate change problems ○ Responding to the warming that has already or will inevitably occur ○ Plant crops to match new climate, capture and conserve water, pursue better fire prevention management, improve disease surveillance Drawdown GA 5 high impact areas identified by GA Drawdown: ○ Electricity ○ Building and materials ○ Food and agriculture ○ Land sinks ○ Transportation Lecture 13 Freshwater / Distribution of Water on Earth Only 2.5% of water on earth is freshwater ○ Not all accessible and not evenly distributed on the planet Total global water: ○ Salt water 97.5% ○ Freshwater 2.5% Freshwater ○ Glacier and ice caps 68.7% ○ Groundwater 30.1% ○ Surface water 1.2% Surface water ○ Ground ice and permafrost 69% ○ Lake/wetlands 23.5% The Water Cycle Water cycle: the movement of water through various water compartments such as surface waters, atmosphere, soil, and living organisms Water vapor that forms clouds and returns as precipitation comes from evaporation from water bodies and evapotranspiration from plants Evapotranspiration: the combination of evaporation and transpiration Hurricanes Hurricanes forms & the role of warm water: ○ Warmer sea surface temps lead to greater hurricane strength because they provide more energy to fuel the storm by increasing the amount of water vapor that evaporates from the ocean surface ○ Warmer oceans act like a larger “fuel source” for hurricanes, allowing them to intensify and produce stronger winds and heavier rainfall 8 category 4-5 hurricanes have made landfall in the U.S. in 8 years Hurricanes form in tropical waters ○ Waters need to be at least 80* F for hurricanes to form The warmer the water, the more it will intensify A warmer atmosphere will hold more water Total damage and economic impact from Helene could be at $110 billion Long-term Relationship with Water and Humans Human water needs: ○ Acquire water (surface water or groundwater) Requires power-- needs to be pumped ○ Drinking water treatment (requires power) ○ Wastewater treatment (most requires power) ○ “Assimilative capacity” of a water body (typically river) to accept waste Groundwater: water found underground trapped in soil or porous rock ○ Supplies can shrink due to over-withdrawal and to decreased infiltration Causes wells to run dry or become contaminated with saltwater (coastal regions) ○ Aquifer: an underground, permeable region of soil or rock that is saturated with water ○ Infiltration: the process of water soaking into the ground As water travels through the soil and rocks, it is filtered ○ Water table: the uppermost water level of saturated zone of an aquifer ○ Saltwater intrusion: the inflow of ocean (salt) water into a freshwater aquifer that happens when an aquifer has lost some of its freshwater stores  Surface water: any body of water found above the ground, such as oceans, rivers, and lakes ○ Provide freshwater to human communities ○ If we remove water faster than it is replaces, the sources can run dry Global Water Use Global water use by sector: ○ Agriculture 69% The biggest use of water (72%) In countries of South Asia, over 90% of their total usage goes to irrigation Agriculture withdrawals in the U.S. are 42% of our water use and surface and groundwater contribute about equally to irrigation The Ogallala (High Plains) aquifer is the largest groundwater system in North America, supplying 30% of all U.S. irrigation water ○ Industry 19% Varies from country to country Water use is higher in wealthier nations In the U.S., power generation accounts for around 85% of the industrial sector’s use of water ○ Domestic 12% Domestic water: indoor and outdoor water used by households and small businesses Uses the least amount of water Water use goes up as income levels increase The per capita domestic water use in the U.S. is almost 3 times the World average Domestic Water Use Safe Drinking Water Act (SDWA) ○ Potable: water that is clean enough for consumption ○ SDWA: federal law that protects public drinking water supplies in the U.S. The story of lead in the tap water in Flint, Michigan highlights: ○ An example of an environmental justice disaster Wastewater and Wastewater Treatment Wastewater: used and contaminated water that is released after use by households, businesses, industry, or agriculture (toilets, showers) Wastewater treatment: the process of removing contaminants from wastewater to make it safe enough to release into the environment ○ Centralized: wastewater treatment plant (WWTP) or water reclamation facility (WRF) Sewage is pumped from homes to a central WWTP/WRF to be treated ○ CSO: combined sewer overflow A bad design idea that combines sewage and stormwater Atlanta has now separated these in 27% combined networks, but still a problem in many areas of Atlanta (particularly in low-income areas) ○ Decentralized: septic tanks Takes power to pump and treat the wastewater Discharge permit requires N, P, and D.O. demand Alternative, decentralized septic tank is a concrete box ○ Solids accumulate and liquid waste goes into a “drain field” ○ Nutrients are presumably removed by microorganisms It is homeowners’ responsibility to pump the septic tank every 3-5 years What is the goal of wastewater treatment? ○ Remove “enough” contaminants from wastewater before releasing it Water Scarcity Water Scarcity: not having access to enough clean water ○ Physical water scarcity: not enough water is available relative to water demand Water footprint: the water consumed by a given group (that is, person or population) or appropriated and/or polluted by industry to produce products or energy ○ Direct use: water used to meet personal needs of cooking, washing, toilet flushing, and so on (domestic) Average U.S. citizen uses about 130 gallons of water per day ○ Indirect use: water used on our behalf by the industry to produce the products and energy that we consume  Adding in the water footprint of goods consumed increases the average daily use of water to 1,100 gallons per person in the U.S. Technologies that Address Water Scarcity Dams: structures that blocks the flow of water in a river or stream ○ Common in areas where lakes and rivers are an important source of water ○ Many negative impacts on aquatic life- particularly migratory ○ If old, can burst and cause downstream loss of life Desalination: the removal of salt and minerals from seawater to make it suitable for consumption ○ Common in coastal areas but limited to wealthy nations as it is an expensive process both energetically and monetarily Recycling Wastewater ○ Microfiltration, reverse osmosis, UV light treatment Underground storage ○ In wet years in Cali’s central valley farmland, water is captured and diverted to pounds or applied to areas where it will soak into the ground helping to refill depleted aquifers Which technology to increase water supplied most closely mimics how nature operates? ○ Recycling wastewater Lecture 14 Rachel Carson / Silent Spring Silent Spring was published in 1962 Warned of the effects of DDT and sparked greater environmental awareness Clean Water Act 1972 (CWA): inspired by the Cuyahoga River which caught fire in 1969 due to so many pollutants ○ Performance standards: the levels of pollutants allowed to be present in the environment or released over a certain time period ○ CWA was enacted by Congress “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters” ○ It’s targeted goal is to make all waters “fishable and swimmable” Assessing Water Quality Chemical assessment: chemical parameters of water quality such as pH and dissolved oxygen (DO) content are monitored to see if these values are within acceptable limits for the organisms who live there Physical assessment: physical parameters that are assessed include the waters turbidity (cloudiness) and temperature (higher temperatures mean lower DO levels) Biological assessment: the process of sampling an area to see what lives there as a tool to determine how healthy the area is Benthic macroinvertebrates: easy-to-see (not microscopic) arthropods such as insects that live on the stream bottom ○ Abundance and diversity of pollution-tolerant and pollution-sensitive species in the sample can be used to “rate” the stream quality Athens is in the upper Oconee River watershed ○ The local volunteer group, UOWN, has been keeping track of the health of the rivers and streams for more than 20 years Water quality can be monitored by checking: ○ pH, turbidity, aquatic organisms What are two aspects of water chemistry that help assess water quality? ○ pH and DO (dissolved oxygen) U.S. Water Quality National Rivers and Streams Assessment (NRSA): a collaborative survey that provides information on the ecological condition of the nation’s rivers and streams and the key stressors that affect them, both on a national and ecological scale ○ 2018-2019 (published 2023): less than one-third of our river and stream miles (28%) had healthy biological communities, based on the analysis of benthic macroinvertebrate communities ○ Close to half of the river and stream miles (47%) were in poor condition ○ Just over one-third (35%) of river and stream miles had healthy fish communities Fish community health was based on fish abundance and diversity ○ 16% of the river and stream miles were not assessed for fish  ○ The remainder (49%) were in fair and poor condition What is considered the main cause associated with poor biological communities? ○ The “stressor” is a factor that impacts organisms or ecosystems, causing a change in condition or functioning Nutrients (phosphorus and nitrogen) were the most widespread stressors ○ 42% of the nation’s river and stream miles were in poor condition, which elevated levels of phosphorus, and 44% were in poor condition for nitrogen Reducing nutrient pollution could improve biological condition National Lakes Assessment 2022- published 2024 ○ Nutrient pollution was the most widespread stressor measured Across the country, 50% of lakes were in poor condition with elevated phosphorus, and 47% were in poor condition with elevated nitrogen ○ High levels of algae and cyanobacteria growth were observed CyanoHABS / Cyanobacteria cyanoHABS: cyanobacterial harmful algal blooms ○ Blooms: rapid increase and accumulation in population of certain algal taxa Traits of cyanoHABS: ○ Toxic (many species have toxins) ○ Hypoxia-generating ○ Alter food-webs Cyanobacteria: a group of photosynthetic organisms like algae that are prokaryotic (lacks nucleus and other organelle with membranes) and therefore are considered bacteria ○ Some produce toxins ○ Many are difficult for aquatic organisms to eat ○ They occur in lakes, reservoirs, rivers, estuaries, coastal waters Water Crisis Causes and impacts of water pollution: ○ Caused by human actions ○ Decreases usable water supply ○ Harms wildlife, human life  Hypoxia: a situation in which a body of water contains inadequate levels of oxygen, compromising the health of many aquatic organisms ○ Cause of the hypoxia is fertilizer runoff (and loss of nutrient retaining wetlands) from the U.S. Midwest Deadzone in the Gulf of Mexico ○ Caused by excess nutrients from the U.S. Midwest (and the loss of wetlands to retain and process nutrients)-- Mississippi River Watershed ○ They have mapped out a hypoxic zone that has grown from 15 square miles in 1988 to a peak of 8,776 sq mi in 2017 ○ 3000-6000 sq mi in the last few years ○ The national oceanic and atmospheric administration (NOAA) estimates that the Gulf of Mexico dead zone costs millions of dollars in lost revenue to the seafood and tourism industries each year ○ Farms, cities, and highways all contribute to pollution in the Mississippi River watershed ○ About $500 million worth of fertilizer washes off of farm in the U.S. midwest Water Pollution Water pollution: the addition of any substance to a body of water that might degrade its quality ○ Pollutants like raw sewage and industrial chemicals get dumped directly into water ○ Contaminants like mercury and other air pollutants from fossil fuel combustion fall back to Earth with the rain and flow into water bodies like rivers and lakes ○ Nutrients from fertilizers and animal waste, pesticides, and sediments from soil erosion flow into surface waters from farms, construction sites, or heavily eroded stream banks Point source pollution: pollution from wastewater treatment plants or industrial sites, such as that from discharge pipes or smokestacks ○ Source is easily identified and remedied ○ About 50% of U.S. streams and rivers meet the fishable/swimmable goal Effluent: wastewater discharged into the environment Nonpoint source pollution: runoff that enters the water from overland flow ○ Has been harder to address  ○ Contaminated runoff is the leading cause of water pollution today ○ The CWA needs to more directly address nonpoint source pollution ○ ex) atmospheric emissions from burning coal Storm-water runoff: water from precipitation that flows over the surface of the land ○ Includes nutrients, pesticides, sediments, and trash that originate from land-based sites like farms, suburban lawn, city streets, and construction sites ○ Includes air pollutants that fall to earth with precipitation A problem in Atlanta and some other cities that built sewer systems connected to stormwater (storm drain) systems is CSOs (combined sewer overflows) CSO’s collect sewage and stormwater in the same pipe for treatment ○ They threaten human health and coastal ecosystems ○ 1. Storm water can fill up and overwhelm sewers ○ 2. Diluted sewage bypasses treatment and spills into surface waters CSOs Solutions To separate stormwater conveyances from sewer pipes Increase the storage capacity of combined sewer systems (gray infrastructure) Reduce the amount of rain that enters the system (GREEN INFRASTRUCTURE) Eutrophication Dissolved oxygen (DO): the amount of oxygen in the water Hypoxia: a situation in which a body of water contains inadequate levels of oxygen, compromising the health of many aquatic organisms ○ Water holds less oxygen than air ○ Aquatic organisms need oxygen for cellular respiration ○ Waters so depleted of oxygen that aquatic life suffers are known as dead zones Eutrophication: a process by which excess nutrients in aquatic ecosystems feed biological productivity, ultimately lowering the oxygen content in the water ○ Dead algae and plants are consumed by bacterial decomposers who also consume oxygen ○ The result is even lower oxygen levels, which kills aquatic organisms including fish  When eutrophication occurs, decomposition increases, and the amount of dissolved oxygen (DO) declines. This creates a condition known as: ○ Hypoxia Which of the following would NOT be evidence that pollution was entering the Gulf of Mexico ○ Thriving fish population Watersheds Watershed: the land area surrounding a body of water over which water such as rain can flow and potentially enter that body of water ○ The entire Mississippi River watershed drains into the Gulf of Mexico ○ The Mississippi River begins in Minnesota Toxins in Water and Fish Tissue Contaminants were present in all fish tissue after National Rivers and Streams Assessment, but risk varied by contaminant and fish consumption levels Concentrations exceeded screening levels as follows: ○ Mercury: 26% of fish had mercury concentrations above human health risks based on consumption Comes from coal burning and other sources Distributed widely in the atmosphere and deposits in water bodies ○ Total PCBs: 45% of fish had PCB concentrations above human cancer risks based on consumption for general fish consumers, 75% for high-frequency gish consumers Industrial chemicals mostly phased out but persist in the environment (not broken down) ○ PFOS was detected in 91% of the 290 fish samples analyzed for NRSA Flame retardants, non-stick They are a current focus of concern (persistent and widespread) Toxic substance/toxic: a substance that causes damage when it contacts, or enters, the body ○ ex) poison, irritant, sensitizer, teratogen, carcinogen  Acute effect: adverse reaction that occurs very rapidly after exposure to a toxic substance has occurred ○ ex) death due to ingestion of poison, headache or breathing difficulty from inhaling fumes Chronic effect: adverse reaction that happens only after repeated long-term exposure to low doses of toxic substance ○ ex) health problems associated with inhaling polluted air over decades, decrease in sperm counts in males exposed to estrogen mimics Potency: the dose size required for a chemical to cause harm Persistence: a measure of how resistant a chemical is to degradation Solubility: the ability of a substance to dissolve in a water- or fat-based liquid or gas (toxins that are fat soluble are more difficult to excrete and accumulate and biomagnify) Bioaccumulation: the build-up of a substance in the tissues of an organism over the course of its lifetime Biomagnification: the increased concentration of substances in the tissue of animals at successively higher levels of the food chain Factors that affect toxicity: ○ Individual: age, illness, genetic predisposition ○ Exposure: exposure dose, frequency of exposure, route of exposure (inhaled, ingested, etc) Lecture 15 Ocean Warming and Acidification CO2 levels in the atmosphere have been increasing since humans started using fossil fuels More CO2 is released than natural processes can remove, and this results in an increasing concentration of atmospheric CO2 ○ There is 50% more CO2 in the atmosphere today than there was before the Industrial Revolution Consequences: ○ CO2 traps heat in the atmosphere  ○ Air temperatures rising mean water temperatures also rise How do most of the CO2 produced from fossil fuels enter our oceans? ○ At the air-water interface Acidification: the lowering of the pH of a solution ○ Normal seawater has an average pH of around 8.2 (slightly basic/alkaline) ○ CO2 emissions have been reduced the ocean’s pH by about 0.1 which is a 30% increase in acidity ○ 0 = most acidic, 7 = neutral ○ Ocean pH has been slightly basic, averaging at about 8.2 Today, it is around 8.1, which represents a 30% increase in acidity over the past two centuries ○ pH is the -log[H+] (the negative log value of concentration of hydrogen ions, also known as protons) H+ is what makes acid acidic How would you describe the relationship between seawater pH and atmospheric CO2? ○ As atmospheric CO2 increases, seawater pH decreases If present trends continue, by 2100, the ocean’s surface waters will be about 150% more acidic than they were in the 1800s Inorganic Carbon In water, inorganic carbon exists in 4 forms Inorganic carbon is what is used by algae for photosynthesis in the ocean When it is “fixed” in photosynthesis, it is an organic form of carbon Any tissue or molecule that is or was a living thing is “organic carbon” 4 forms of inorganic carbon in water ○ Carbon dioxide (CO2+H2O) ○ Carbonic acid (H2CO3) ○ Bicarbonate ○ Carbonate If you add more CO2, you reduce the pH (to be more acid) If you add more carbonate (like crushed-limestone-calcium carbonate)- you increase the pH (make it more basic) When CO2 dissolves in water, it makes carbonic acid (H2CO3) Carbonic acid disassociates to make bicarbonate (HCO3) and hydrogen ions (H+) Marine Calcifiers Marine calcifiers: organisms that make a hard calcium-based shell or exoskeleton (oysters, pteropods aka sea butterfly, scallops, other shelled organisms) Coral reefs: a large underwater structure formed by colonies of tiny animals (coral) that produce a calcium carbonate exoskeleton that over time builds up; commonly found in shallow, warm, tropical seas ○ Coral reefs provide many services like protecting coastal areas from storms, providing food and habitat for many species (25% of all ocean species spend at least a portion of their life in a tropical coral reef) Approximately what percentage of threats to reefs come from thermal stress? ○ 15% Even a decline of a few tenths of a pH unit can alter the ability of marine organisms to produce shells (shells would dissolve at 7.6) What chemical makes up the shells of marine calcifiers? ○ CaCO3 When dissolved in water, CO2 forms carbonic acid which: ○ Eats away at existing calcium-based materials ○ Interferes with the chemical reactions by which new ones are made Coral Reefs Major threats to coral reefs include: ○ Overfishing and destructive fishing ○ Inland pollution ○ Coastal development ○ Thermal stress ○ Marine-based pollution Coral: colonial marine animals that secrete hard outer shells in which they live and are mutualistically dependent on an algal partner ○ They live in densely packed colonies of many individual polyps ○ Coral larvae are free floating but must attach to a surface to survive Coral depend on mutualistic relationship with zooxanthellae ○ The zooks provide food and color to the coral and the coral provide habitat, CO2, and food to the zooks  Stressors can cause bleaching (loss of zooks), a potentially fatal event for corals When coral reefs are under stress, the reef can undergo: ○ Coral bleaching Zooxanthellae (zooks): mutualistic photosynthetic algal partner of a coral polyp; each provides nutrients that the other needs Coral bleaching: a stress response in coral in which the mutualistic algal partner is expelled; this weakens and can even kill the coral if it is not recolonized soon Stressors includes: ○ Pollution ○ Salinity changes ○ Low pH ○ Temperatures are too high Which of the following is an outcome of coral bleaching? ○ Decrease in structure that supports fisheries coastal areas Plastic pollution 5 ways plastic debris in oceans also harms marine life ○ Plastics can transport organisms to places they don’t belong and where they can’t survive ○ Fish eggs, barnacles, and other organisms can hitch a ride on floating plastic and travel to new locales where they can become invasive species ○ Sea life can get fatally tangled in discarded shopping bags and plastic six-pack rings ○ Plastics can be mistaken for food and eaten resulting in animals starving to death because plastics take up all the room in the gut ○ Organisms can also be harmed by the toxic chemicals the plastics harbor The world produces around 400 million tons of plastic each year ○ Only 9% is recycled; 79% ends up in landfills or open waste pits By 2015, we had produced 8,3 billion metric tons of plastic By 2025, we had produced 6.3 billion metric tons of plastic Microplastic are now found everywhere and they may have toxic substances in them (flame retardants applied to clothing) and they absorb toxic substances from the surrounding water