Ear 111 Practice Final

The correct answer is 8. Seawater is slightly alkaline, with a pH value of around 8. This is due to the presence of dissolved salts and minerals, such as carbonates and bicarbonates, which act as buffers and help maintain the pH level. A pH of 8 is considered to be within the normal range for seawater and is important for the survival of marine organisms. It is also worth noting that the pH of seawater can vary slightly depending on factors such as location, temperature, and pollution levels.

The comparison of temperature patterns within the atmosphere between the observation and the model calculations indicates that the cause of the most recent changes is human activity. This is because the term "human" is the only option provided that can be linked to human-induced changes in the atmosphere. The other option, "nature," is more general and does not specifically attribute the changes to human influence. Therefore, the correct answer is "human."

Secretary of Energy Steven Chu proposed to use white roofs for reflecting solar heat. This is because white roofs have a higher albedo, meaning they reflect more sunlight back into space rather than absorbing it. This helps to reduce the amount of heat that is transferred into buildings, thus decreasing the need for air conditioning and ultimately reducing energy consumption. Additionally, white roofs can help mitigate the urban heat island effect by lowering surface temperatures in cities.

The correct answer is drought. The disappearance of the Mayan civilization is believed to be linked to a prolonged period of drought. Climatologists have found evidence of a severe and extended dry spell during the time when the Mayan civilization collapsed. This drought would have caused crop failures, water shortages, and ultimately led to societal collapse. The lack of rainfall would have had a devastating impact on agriculture, which was the main source of sustenance for the Mayans. As a result, the Mayans were forced to abandon their cities and disperse in search of more favorable conditions.

Ocean acidification refers to the decrease in pH levels of the Earth's oceans, making them more acidic. This process is primarily caused by the increased concentration of carbon dioxide (CO2) in the atmosphere, which is a result of human activities such as burning fossil fuels. When fossil fuels are burned, they release CO2 into the atmosphere, which then gets absorbed by the oceans. This leads to a chemical reaction that increases the acidity of the water, posing a threat to marine life and ecosystems. Therefore, fossil fuel burning is the correct answer for the cause of recent ocean acidification.

During the Last Glacial Maximum (LGM), Canada was covered by the Laurentide ice sheet. The Laurentide ice sheet was the largest ice mass during the LGM and extended across much of North America, including most of Canada and parts of the northern United States. It was formed by the accumulation of snow over thousands of years, which gradually compressed into ice. The Laurentide ice sheet played a significant role in shaping the landscape of Canada, leaving behind glacial landforms such as moraines, eskers, and drumlins.

During the Little Ice Age, lichens on Canadian Baffin Island were killed due to the lack of sunlight. Lichens are symbiotic organisms that require sunlight for photosynthesis, which is their primary source of energy. The reduced sunlight during the Little Ice Age would have limited the ability of lichens to produce food, leading to their death. This lack of sunlight would have had a significant impact on the survival and growth of lichens in the region.

Pau Crutzen, a Nobel prize winner, suggested that by creating sulfate aerosol in the stratosphere, it could potentially cool down the earth. The stratosphere is the second layer of the Earth's atmosphere, located above the troposphere. This proposal is based on the idea that the sulfate aerosols would reflect sunlight back into space, reducing the amount of solar radiation reaching the Earth's surface and thus lowering temperatures.

CO2 forms hydrate at high pressure and low temperature conditions at seafloor, which can be used to store C.

As the climate becomes warmer, it leads to increased evaporation of water. This increased evaporation results in more water vapor in the atmosphere, which enhances the greenhouse effect. The greenhouse effect then traps more heat in the atmosphere, further contributing to a warmer climate. This feedback loop is known as a positive feedback, as each step reinforces and amplifies the initial warming trend. Therefore, the correct answer is positive and warmer.

AI(OH)3 is not the product of carbon sequestration because it does not contain carbon. Carbon sequestration refers to the process of capturing and storing carbon dioxide (CO2) to prevent it from being released into the atmosphere. CaCO3, MgCO3, and FeCO2 all contain carbon and are formed through the sequestration of carbon. However, AI(OH)3 is aluminum hydroxide and does not contain carbon, so it is not a product of carbon sequestration.

The first step in deriving the temperature of the geologic past is to establish a modern calibration. This involves gathering data on current temperature patterns and using it as a reference point. The next step is to collect fossil data, which provides information about past climates. Once the fossil data is collected, the paleo-T (paleo-temperature) can be calculated using various methods and techniques. Finally, cross-checking between proxies is done to ensure the accuracy and reliability of the temperature reconstruction. Therefore, the correct order is i, iii, ii, iv.

During the Younger Dryas period, there was a sudden and significant cooling of the Earth's climate. Wally Broecker proposed that this cooling was caused by the influx of meltwater from the North American ice sheet into the North Atlantic. This influx of freshwater disrupted the thermohaline circulation, which is the global oceanic circulation system driven by differences in temperature and salinity. The disruption of this circulation system resulted in a decrease in the transport of heat from the equator to the poles, leading to the cooling of the climate during the Younger Dryas.

Understanding climate change involves a three-step process. First, observations are made to gather data on various aspects of the climate system, such as temperature, precipitation, and greenhouse gas concentrations. These observations provide a foundation of empirical evidence. Second, interpretation is necessary to analyze and make sense of the observed data. This involves identifying patterns, trends, and relationships within the data and determining their significance. Finally, prediction involves using the observed data and interpreted patterns to make projections about future climate conditions and potential impacts. Therefore, the correct order for the process of understanding climate change is observations, interpretation, and prediction.

The collapse of the Tang Dynasty and Mongol empire in China coincided with weak monsoon. Weak monsoon refers to a decrease in the intensity or duration of the monsoon season, which can lead to reduced rainfall and drought conditions. This could have had a significant impact on agriculture, causing crop failures and food shortages, ultimately contributing to the downfall of these empires.

During the time period of 1800-1900, El Nino events were more frequent compared to the other time periods listed.

During glacial periods, part of atmospheric carbon was stored in the ocean. This is because colder temperatures during glacial periods caused the oceans to absorb more carbon dioxide from the atmosphere. The increased solubility of carbon dioxide in cold water allowed the ocean to act as a carbon sink, effectively storing carbon and reducing its concentration in the atmosphere. This process helped to regulate the Earth's climate by removing carbon dioxide, a greenhouse gas, from the atmosphere and reducing its warming effect.

In a higher CO2 world, biological calcification becomes harder because increased CO2 levels lead to ocean acidification, making it more difficult for organisms to form calcium carbonate structures. On the other hand, carbonate dissolution becomes easier as higher CO2 levels increase the acidity of the ocean, causing the dissolution of carbonate minerals.

The correct answer is "steadily rising." This means that the temperature has been consistently increasing over the last 50 million years.

The given information states that glacial-interglacial CO2 fluctuations range from 200 to 280 ppm. The question asks for the current atmospheric CO2 level above the interglacial maximum value. Since the interglacial maximum value is 280 ppm, the current atmospheric CO2 level is 100 ppm above that value.

The correct order of deep water oxygen level from high to low is Pacific, Indian, Atlantic.

Strong ocean deoxygenation events in the past caused an increase in the deposition of organic matter in marine sediments. This organic matter eventually became buried and preserved in geological deposits, specifically in organic rich shale. Shale is a type of sedimentary rock that forms from the compaction of fine-grained sediments, and when it contains a high amount of organic material, it is referred to as organic rich shale. Therefore, it is likely that strong ocean deoxygenation events in the past left organic rich shale in geological deposits.

The term LGM refers to the Last Glacial Maximum, which was the most recent period of strong glaciation. During this time, large parts of the Earth were covered in ice sheets and glaciers, resulting in a significant drop in global temperatures. The LGM occurred approximately 20,000 years ago and marked the peak of the last ice age.

Lake sediments can provide valuable information about the history of N. American ice sheet retreat because they contain organic material that can be radiocarbon dated. By analyzing the age of the organic material in the sediments, scientists can determine when the ice sheet retreated and the lake formed. This information helps to reconstruct the timeline of ice sheet retreat and understand the patterns and processes involved in the changing climate of North America.

LGM refers to the Last Glacial Maximum, which was a period of maximum extent of ice sheets and glaciers during the last ice age. The question is asking for the approximate time in thousands of years ago when the LGM occurred. The correct answer is 20, indicating that the Last Glacial Maximum was approximately 20,000 years ago.

The figure on the right shows that the recent alkenone-based tropical sea surface temperature for the Last Glacial Maximum (LGM) is lower than the estimates provided by CLIMAP. This suggests that there is a larger temperature fluctuation in the tropics, which could explain the debate about warm tropics. The fact that the alkenone-based data shows lower temperatures than the CLIMAP estimates implies that there may be significant variations in temperature in the tropical regions, leading to the debate about the warmth of the tropics.

The reversal in CO2 and CH4 trends around 8-5 ka is related to agriculture. This is because the development of agriculture during this time period led to an increase in human population and the expansion of farming practices. These practices, such as deforestation and the use of fire for land clearance, resulted in the release of carbon dioxide and methane into the atmosphere. Therefore, the increase in greenhouse gas emissions from agricultural activities caused the reversal in the trends of CO2 and CH4 during this period.

The Paleocene-Eocene Thermal Maximum is an example of severe ocean acidification due to rapid carbon release in geological history. During this event, which occurred approximately 55 million years ago, there was a significant increase in atmospheric carbon dioxide levels. This led to a rapid increase in ocean temperatures and a subsequent acidification of the oceans. The acidification had detrimental effects on marine life, causing mass extinctions of various species. Therefore, the Paleocene-Eocene Thermal Maximum is a well-documented example of how rapid carbon release can result in severe ocean acidification.

The melting of mountain glaciers and sea-ice, frequent El Nino events, and frequent droughts and stronger tropical storms are all known effects of warming since 1800. However, the stopping of thermohaline circulation is not one of these effects. Thermohaline circulation refers to the global ocean currents driven by temperature and salinity differences. While climate change can affect ocean circulation patterns, there is currently no evidence to suggest that it has caused a complete stoppage of thermohaline circulation.

The figure shows that human footprint correlates with recent hypoxic events, meaning that there is a connection between human activities and the occurrence of these events. The question asks for the cause of this correlation, and the correct answer is CO2 pollution. CO2 pollution refers to the release of carbon dioxide into the atmosphere through various human activities, such as burning fossil fuels. This excess CO2 in the atmosphere contributes to global warming and ocean acidification, which in turn can lead to hypoxic events in marine ecosystems.

The major controls of O2 level beneath the surface ocean are ventilation, temperature, and oxygen utilization. Atmospheric CO2 does not directly control the O2 levels in the ocean, so it is not considered one of the major controls.

The shallow hypoxic depth of the North Pacific is largely due to poor ventilation. Poor ventilation refers to the limited exchange of oxygen between the surface and deeper waters. This can occur due to factors such as weak winds, stable water column, and low mixing of surface and deep waters. As a result, oxygen levels decrease with depth, leading to hypoxic conditions. Other factors like oxidation of organic matter, dissolution of CO2, and photosynthesis may also contribute to hypoxia, but poor ventilation is the primary reason in the North Pacific.

Marine animals have varying abilities to tolerate low oxygen conditions. Some species have evolved adaptations that allow them to survive in environments with low oxygen levels, while others are more sensitive and cannot tolerate such conditions. Therefore, the tolerance of low oxygen condition in marine animals is highly variable.

Temperate areas would be the most ideal place for afforestation and decrease of deforestation rate to lower CO2 levels. This is because temperate areas have a moderate climate and abundant rainfall, which are conducive to the growth of trees and other vegetation. Additionally, temperate areas often have a higher population density and more developed infrastructure, making it easier to implement and manage afforestation projects. By increasing the forest cover in temperate areas, the absorption of CO2 through photosynthesis can be maximized, helping to reduce the overall CO2 levels in the atmosphere.

The unusual air circulation pattern is the correct answer because it does not describe typical El Nino conditions in the tropical Pacific ocean. During El Nino, there is a reversal in the trade winds, resulting in a weakening or even a reversal of the normal east-to-west winds. This leads to changes in the atmospheric pressure patterns and a disruption of the typical air circulation in the region. The other options, such as less rainfall in eastern Pacific, warming of surface water, and weakened upwelling in eastern Pacific, are all characteristic of El Nino conditions.

Geological sequestration of CO2 is a safe and cost-effective approach, as it involves storing CO2 underground in geological formations. However, the potential issue of leakage needs to be controlled and monitored over the long-term to ensure that the stored CO2 does not escape back into the atmosphere.

Over a time scale of over 100 million years, the most significant source of atmospheric CO2 is the mantle. The mantle is the layer of the Earth between the crust and the core, and it contains a large amount of carbon in the form of carbonates and other minerals. Through processes like volcanic activity and tectonic plate movement, carbon from the mantle can be released into the atmosphere as CO2. This long-term release of CO2 from the mantle contributes to the overall levels of atmospheric CO2 over millions of years.

The correct answer is at high latitude N. hemisphere. The Medieval Warm Period and Little Ice Age were two distinct climatic periods that occurred during the Middle Ages. This record was obtained at high latitude in the Northern Hemisphere, which means it refers to the regions closer to the North Pole. This is significant because it suggests that the climate changes during these periods were more pronounced in the northern parts of the world.

The transition between the 41 kyr cycle and 100 kyr cycle happened roughly between .7 and 1.2 million years ago.

During the Last Glacial Maximum (LGM), which occurred around 20,000 years ago, the Earth experienced a significant cooling period with extensive ice sheets covering large parts of the planet. Despite the overall colder climate, the distribution of solar radiation or insolation during the summer season was found to be similar to today's levels. This suggests that while the average temperature was lower during LGM, the amount of solar radiation received during the summer months was comparable to present-day conditions.

The correct answer is "ice-sheet response can pre-date insolation." This means that the melting of the ice sheet can begin before the increase in summer insolation around 10ka. This suggests that other factors, such as changes in ocean circulation or atmospheric conditions, could have influenced the melting of the ice sheet before the peak in insolation.

The leading hypothesis to explain millennial oscillations in high resolution ice-core records is greenhouse gas oscillation. This suggests that changes in greenhouse gas concentrations, such as carbon dioxide and methane, play a significant role in driving these oscillations. As greenhouse gases increase, they trap more heat in the atmosphere, leading to warming. This warming can then cause ice sheets to melt, which can further impact climate patterns. The oscillations observed in ice-core records are believed to be a result of these complex interactions between greenhouse gases, ice-sheet melting, and climate.

The North Pacific Ocean has the largest volume of suboxic water. Suboxic water refers to areas in the ocean where oxygen levels are extremely low, creating conditions that are unfavorable for most marine life. The North Pacific Ocean has a larger volume of suboxic water compared to the other options listed.

Oxygen utilization in seawater is mostly due to the oxidation of organic matter. Organic matter in the form of dead plants, animals, and other organic substances undergoes a process called oxidation, where oxygen is consumed. This process is carried out by bacteria and other microorganisms present in the water. They break down the organic matter, releasing energy and consuming oxygen in the process. This is a vital process in marine ecosystems as it helps in the decomposition of organic material and recycling of nutrients.

The main orbital cycles that affect glacial cycles are precession, tilt, and eccentricity. The solstice, on the other hand, is not an orbital cycle, but rather a point in the Earth's orbit where the tilt of the Earth's axis is at its maximum or minimum. Therefore, the solstice is not one of the main orbital cycles that affect glacial cycles.

Tree rings are very useful climate records for many reasons because they provide precise age control, are easy to sample, and have a long record. However, their availability is not one of the reasons why tree rings are useful as climate records.

The correct answer is Savanna; C3 to C4. This is because the hypothesis suggests that long-term drying of Africa transformed rainforests into grasslands, which influenced early human evolution. The evidence for this hypothesis comes from C13 changes, which are related to the shift from C3 vegetation (typical of rainforests) to C4 vegetation (typical of grasslands).

The correct answer is "radioactivity and d18O". This is because d18O is a stable isotope of oxygen that can provide information about past climate conditions, including the presence of CO2 from fossil fuel burning. Radioactivity can also be used as a tracer to determine the source of CO2 emissions, as certain isotopes are associated with specific processes such as nuclear power generation. Therefore, the combination of radioactivity and d18O can provide clear signals indicating the rising CO2 levels caused by fossil fuel burning.

According to the CLIMAP reconstruction, the global sea surface temperature (SST) during the Last Glacial Maximum (LGM) was generally higher than today's SST in most ocean basins, except for the Atlantic.

The correct answer is "decomposed; taken up". The oxygen minimum zone is a water depth where organic matters are decomposed, meaning they break down into simpler substances. This decomposition process consumes oxygen, resulting in low oxygen levels in this zone. At the same time, nutrients are taken up by organisms present in the zone.