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Marine ecosystems are defined by their presence in saltwater environments with high salt content, distinguishing them from freshwater ecosystems.
Answer: True
Explanation: Marine ecosystems are characterized by their location in saltwater environments with high salt content, distinguishing them from freshwater ecosystems which have low salt concentrations. They cover over 70% of Earth's surface.
Estuaries are characterized by variable salinity due to the mixing of freshwater and saltwater, not a consistent high salinity.
Answer: True
Explanation: Estuaries are defined by the mixing of freshwater and saltwater, resulting in brackish water with variable salinity, which is a key characteristic differentiating them from the open ocean.
Intertidal zones are environments that are exposed to air at low tide and submerged at high tide, not permanently submerged.
Answer: True
Explanation: Intertidal zones are defined by the cyclical exposure to air during low tide and submersion by saltwater during high tide.
Sea spray plays a role in transporting marine microorganisms globally through the atmosphere.
Answer: True
Explanation: Marine microorganisms can be carried into the atmosphere via sea spray, enabling global transport and deposition.
What is the primary characteristic that defines a marine ecosystem?
Answer: Location in saltwater environments with high salt content.
Explanation: Marine ecosystems are fundamentally defined by their presence in saltwater environments characterized by high salt concentrations, distinguishing them from freshwater systems.
Which of the following is NOT listed as a primary zone of marine ecosystems in the text?
Answer: Terrestrial zone
Explanation: The primary zones discussed for marine ecosystems include the oceanic, benthic, and intertidal zones, among others. The terrestrial zone is not considered a marine ecosystem zone.
Estuaries are described as highly productive ecosystems primarily because they:
Answer: Feature a unique mix of fresh and saltwater (brackish water).
Explanation: The high productivity of estuaries is largely attributed to the dynamic mixing of freshwater and saltwater, creating brackish conditions that support specialized and abundant life.
Which of the following organisms are typically found in the high intertidal zone?
Answer: Barnacles, mussels, and hermit crabs
Explanation: The high intertidal zone, subject to prolonged periods of air exposure, supports resilient organisms such as barnacles, mussels, and hermit crabs.
Which zone is characterized by being exposed to air at low tide and submerged at high tide?
Answer: Intertidal zone
Explanation: The intertidal zone is defined by its position between high and low tide marks, experiencing alternating periods of aerial exposure and marine submersion.
Coral reefs are complex ecosystems built by large colonies of coral species, and they are ecologically vital.
Answer: True
Explanation: Coral reefs are indeed built by colonies of coral species and are recognized as ecologically crucial, supporting immense biodiversity.
Mangrove ecosystems primarily serve to protect coastlines from erosion and sequester carbon dioxide.
Answer: True
Explanation: Mangrove ecosystems are vital for coastal protection, reducing erosion, and play a significant role in sequestering atmospheric carbon dioxide.
Seagrass meadows are considered among the most productive ecosystems globally.
Answer: True
Explanation: Seagrass meadows are recognized as highly productive ecosystems, providing essential habitats and nursery grounds for marine life.
Kelp forests are primarily found in temperate coastal waters and are significantly affected by human activities.
Answer: True
Explanation: Kelp forests are predominantly found in temperate coastal regions and are notably impacted by human activities such as overfishing and climate change.
Lagoons are typically shallow bodies of water, highly affected by precipitation and evaporation.
Answer: True
Explanation: Lagoons are often shallow and their salinity and temperature can fluctuate significantly due to factors like precipitation, evaporation, and wind.
The high marsh zone in salt marshes is flooded only by higher tides, not daily tides.
Answer: True
Explanation: The high marsh zone within salt marshes experiences inundation only during periods of higher tides, distinguishing it from the low marsh which is flooded more frequently.
Seagrass meadows and mangrove forests contribute to 'blue carbon' by sequestering atmospheric carbon dioxide.
Answer: True
Explanation: Coastal ecosystems like seagrass meadows and mangrove forests are significant 'blue carbon' sinks, effectively sequestering atmospheric carbon dioxide.
'Blue carbon' refers to carbon stored in coastal and marine ecosystems, not terrestrial forests.
Answer: True
Explanation: Blue carbon specifically denotes carbon captured and stored within coastal and marine ecosystems, such as mangroves and seagrass beds.
Salt marshes are characterized by peat, a waterlogged, decomposing plant matter creating low-oxygen conditions.
Answer: True
Explanation: Salt marshes are distinguished by their soil composition, often consisting of peat formed from waterlogged, decomposing plant material under anaerobic conditions.
Which near-shore marine ecosystem is described as being built by large colonies of coral species?
Answer: Coral reefs
Explanation: Coral reefs are complex structures built by the collective action of numerous coral polyps, forming vital near-shore ecosystems.
What is a key ecological role of mangrove ecosystems mentioned in the text?
Answer: Providing coastal protection and sequestering carbon dioxide.
Explanation: Mangrove ecosystems provide critical services, including mitigating coastal erosion through their root systems and acting as significant carbon sinks.
Seagrass meadows are identified as important nursery grounds for which group?
Answer: Commercial fish species
Explanation: Seagrass meadows serve as crucial nursery habitats for numerous species, including many that are commercially important for fisheries.
What human activities are cited as major contributors to the degradation of kelp forests?
Answer: Overfishing and climate change.
Explanation: Kelp forests face significant degradation due to human activities, primarily overfishing, which can disrupt trophic balances, and the impacts of climate change.
What characteristic makes lagoon salinity and temperature highly variable?
Answer: Their shallow nature and susceptibility to weather.
Explanation: Lagoons, often shallow, exhibit significant variability in salinity and temperature due to their direct exposure to meteorological conditions like precipitation and evaporation.
In a salt marsh, which zone is flooded only during higher tides?
Answer: The high marsh
Explanation: The high marsh zone within a salt marsh ecosystem is characterized by inundation that occurs only during the higher tidal cycles.
The term 'blue carbon' refers to carbon stored in:
Answer: Coastal and marine ecosystems like mangroves and seagrasses.
Explanation: Blue carbon is the carbon sequestered and stored within coastal and marine ecosystems, such as mangrove forests, salt marshes, and seagrass meadows.
Which type of marine ecosystem is known for sequestering significant amounts of carbon annually, contributing to climate mitigation?
Answer: Mangrove forests
Explanation: Mangrove forests are highly effective at sequestering atmospheric carbon dioxide, contributing significantly to climate change mitigation through their 'blue carbon' storage.
What is a major threat to coral reefs mentioned in the context of climate change?
Answer: Ocean warming leading to coral bleaching.
Explanation: Ocean warming, a consequence of climate change, poses a severe threat to coral reefs through phenomena such as coral bleaching.
The oceanic zone refers to the vast open ocean water column, distinct from the benthic zone which is characterized by seafloor substrates.
Answer: True
Explanation: The oceanic zone encompasses the open ocean water column, inhabited by mobile marine life. The benthic zone, conversely, comprises the ocean floor and its substrates, serving as habitat for bottom-dwelling organisms.
Hydrothermal vents support life through chemosynthesis, utilizing chemical energy rather than sunlight, as light does not penetrate the deep sea.
Answer: True
Explanation: Hydrothermal vents are unique deep-sea environments where life is sustained by chemosynthetic bacteria that utilize chemical energy, as sunlight is absent at these depths.
Neuston refers to organisms living at the ocean's surface, not deep within the sediments.
Answer: True
Explanation: Neuston are organisms that inhabit the surface layer of the ocean, such as those found in the Sargasso Sea, distinct from organisms living in deep-sea sediments.
The deep sea and sea floor constitute the largest fraction of Earth's habitable space.
Answer: True
Explanation: The deep sea and sea floor represent the most extensive habitable volume on Earth, potentially encompassing up to 95% of all life.
The benthic zone is defined by the seafloor and its substrates, distinct from the pelagic (water column) zones.
Answer: True
Explanation: The benthic zone encompasses the ocean floor, including sediments and substrates, differentiating it from the pelagic zone which refers to the open water column.
The Sargasso Sea is an example of a neuston community.
Answer: True
Explanation: The Sargasso Sea, characterized by floating Sargassum seaweed, serves as a prominent example of a neuston community, comprising organisms living at the ocean's surface.
According to the source, what forms the base of the food web in deep-sea hydrothermal vent ecosystems?
Answer: Chemosynthetic sulfur bacteria utilizing chemical energy.
Explanation: In deep-sea hydrothermal vent ecosystems, the primary producers are chemosynthetic bacteria that derive energy from chemical compounds, forming the base of the food web in the absence of sunlight.
What term describes organisms that live freely at the ocean's surface?
Answer: Neuston
Explanation: Neuston refers to the assemblage of organisms that inhabit the surface layer of the ocean, living freely on or just below the surface film.
What percentage of Earth's habitable space is estimated to be represented by the deep sea and sea floor?
Answer: Up to 95%
Explanation: The deep sea and sea floor constitute the largest proportion of habitable space on Earth, estimated to be as high as 95%.
What is the primary energy source for life around hydrothermal vents?
Answer: Chemical energy
Explanation: Life around hydrothermal vents is primarily sustained by chemical energy derived from geological processes, utilized by chemosynthetic microorganisms.
Ecosystem engineers, like corals, significantly alter marine habitats and provide essential structural complexity.
Answer: True
Explanation: Ecosystem engineers, such as reef-building corals, fundamentally shape their habitats, creating complex structures that support diverse communities.
The 'paradox of the plankton' questions how high biodiversity is maintained in environments with limited resources.
Answer: True
Explanation: The 'paradox of the plankton' highlights the ecological puzzle of how diverse planktonic communities coexist despite apparent resource limitations and the absence of strong competitive exclusion.
The 'green world hypothesis' suggests herbivores do not consume most plants because they are limited by predation, disease, and resources.
Answer: True
Explanation: The 'green world hypothesis' posits that herbivores are prevented from consuming all plant biomass due to factors such as predation, disease, and resource availability limiting their populations.
The intermediate disturbance hypothesis posits that species diversity is highest in environments with moderate levels of disturbance.
Answer: True
Explanation: The intermediate disturbance hypothesis suggests that species diversity peaks when disturbances occur at moderate frequencies and intensities, balancing competitive exclusion and local extinction.
'Niche construction' involves organisms actively modifying their environment, influencing selection pressures.
Answer: True
Explanation: Niche construction describes the process by which organisms alter their ecological niches and environments, thereby influencing evolutionary trajectories for themselves and other species.
Foundation species, like kelp, have a significant impact on the structure of marine ecosystems.
Answer: True
Explanation: Foundation species are critical architects of ecosystems; for instance, kelp forms forests that provide habitat and resources for numerous other marine organisms.
'Mesopredator release' occurs when the removal of apex predators allows mesopredator populations to increase.
Answer: True
Explanation: Mesopredator release describes the ecological phenomenon where the decline of top predators leads to an increase in populations of smaller predators, altering trophic dynamics.
The 'intermediate disturbance hypothesis' suggests that biodiversity peaks at moderate levels of disturbance.
Answer: True
Explanation: The intermediate disturbance hypothesis posits that species diversity is maximized in ecosystems experiencing moderate levels of disturbance, which prevents competitive exclusion by dominant species while allowing colonization.
What ecological concept describes the removal of top predators leading to an increase in smaller predator populations?
Answer: Mesopredator release
Explanation: Mesopredator release is the ecological process where the reduction or elimination of apex predators allows populations of intermediate-sized predators (mesopredators) to increase.
The 'paradox of the plankton' questions how:
Answer: High biodiversity of plankton is maintained despite limited resources.
Explanation: The 'paradox of the plankton' addresses the ecological question of how a large number of planktonic species can coexist in environments where resources appear limited, challenging simple competitive exclusion models.
According to the 'green world hypothesis', why don't herbivores consume all plants?
Answer: Herbivores are limited by predation, disease, and resources.
Explanation: The 'green world hypothesis' proposes that herbivores do not consume all plant biomass because their populations are regulated by factors such as predation, disease, and the availability of essential resources.
What does the 'intermediate disturbance hypothesis' suggest about species diversity?
Answer: It is highest at moderate levels of disturbance.
Explanation: The intermediate disturbance hypothesis posits that species diversity is maximized when disturbances occur at intermediate frequencies and intensities, fostering a dynamic balance between competitive exclusion and colonization.
Which of the following is an example of an 'ecosystem engineer' in marine environments?
Answer: Reef-building bivalves.
Explanation: Reef-building bivalves are considered ecosystem engineers because their biological structures (reefs) fundamentally alter the physical environment, creating habitats for numerous other species.
What is the primary consequence of 'mesopredator release'?
Answer: Increased predation pressure on lower trophic levels.
Explanation: Mesopredator release typically results in an increase in the populations of mesopredators, which subsequently exert greater predation pressure on organisms at lower trophic levels.
Marine ecosystems provide essential services like climate regulation, food resources, and recreation opportunities.
Answer: True
Explanation: Marine ecosystems offer a broad spectrum of essential services, including climate regulation, provision of food resources, and opportunities for recreation and tourism.
Marine ecosystem productivity is measured using various metrics, not solely chlorophyll-a levels.
Answer: True
Explanation: The assessment of marine ecosystem productivity involves multiple indicators, such as chlorophyll-a, zooplankton composition, and primary production rates, rather than relying exclusively on chlorophyll-a.
Human activities like overfishing and pollution are major threats to marine ecosystems, often exceeding the impact of natural phenomena.
Answer: True
Explanation: Human activities, including overfishing and pollution, represent significant threats to marine ecosystems, frequently surpassing the impact of natural environmental changes.
Ocean acidification, caused by increased atmospheric CO2, harms marine organisms by decreasing seawater pH.
Answer: True
Explanation: Ocean acidification, resulting from the absorption of atmospheric carbon dioxide, lowers seawater pH and negatively impacts marine organisms, particularly those with calcium carbonate structures.
Approximately 13% of the ocean area is considered wilderness, largely untouched by human activity.
Answer: True
Explanation: It is estimated that only about 13% of the global ocean area remains as wilderness, underscoring the widespread influence of human activities.
Coastal marine ecosystems face significant pressure as a large proportion of the global population lives near the coast.
Answer: True
Explanation: Coastal marine ecosystems are under considerable pressure because nearly 40% of the world's population resides within 100 kilometers of the coast.
Overfishing has led to decreased global fisheries landings (despite increased effort) and lower average trophic levels in marine ecosystems.
Answer: True
Explanation: Overfishing contributes to declining fisheries yields and shifts marine food webs towards lower trophic levels, impacting ecosystem structure and function.
The vast majority of marine pollution originates from land-based activities, not solely oceanic activities.
Answer: True
Explanation: Approximately 80% of marine pollution stems from land-based sources, including industrial, agricultural, and residential waste, alongside contributions from marine transportation.
Pollution enters the ocean through various pathways, including land runoff and atmospheric deposition, not mainly through direct ship discharge.
Answer: True
Explanation: Ocean pollution enters through multiple routes, such as runoff from land, atmospheric deposition, and direct discharges, rather than primarily from ship operations.
Invasive species are primarily introduced into marine ecosystems through human-mediated pathways like ballast water transport.
Answer: True
Explanation: Human activities, notably the transport of ballast water in ships and the global aquarium trade, are primary vectors for the introduction of invasive species into marine environments.
'Fishing down the food web' describes the practice of targeting smaller, lower-trophic-level species as larger ones become depleted.
Answer: True
Explanation: The term 'fishing down the food web' refers to the progressive shift in fisheries towards consuming species at lower trophic levels as larger, more desirable species decline.
Which ecosystem service provided by marine environments is crucial for global food supplies?
Answer: Capture fisheries and aquaculture
Explanation: Capture fisheries and aquaculture represent vital ecosystem services derived from marine environments, forming a cornerstone of global food security.
How is the 'transparency' of the water column used in assessing marine ecosystem productivity?
Answer: It indicates the depth of light penetration.
Explanation: Water column transparency is an indicator used in assessing marine productivity, as it relates to the depth to which sunlight can penetrate, influencing photosynthesis.
Besides bottom-trawl surveys, what other method is mentioned for assessing fish populations, specifically for pelagic species?
Answer: Acoustic surveys
Explanation: Acoustic surveys are employed to assess fish populations, particularly pelagic species, complementing methods like bottom-trawl surveys.
Which of the following is a major consequence of ocean warming on marine species?
Answer: Shift in geographical ranges and seasonal activities.
Explanation: Ocean warming compels marine species to alter their geographical distributions and adjust their seasonal activities in response to changing thermal conditions.
What proportion of the ocean is estimated to remain as wilderness?
Answer: Approximately 13%
Explanation: It is estimated that approximately 13% of the ocean's area remains as wilderness, largely unaffected by direct human activities.
Why are coastal marine ecosystems particularly pressured by human populations?
Answer: Nearly 40% of the global population lives within 100 km of the coast.
Explanation: Coastal marine ecosystems face intense pressure due to the high concentration of human populations living near coastlines, leading to increased resource exploitation and habitat alteration.
What is a primary outcome of overfishing on marine ecosystems?
Answer: Reduced fish biomass and biodiversity.
Explanation: Overfishing directly leads to a reduction in fish biomass and biodiversity, often destabilizing marine food webs and diminishing ecosystem resilience.
What percentage of marine pollution originates from land-based activities?
Answer: Approximately 80%
Explanation: The majority of marine pollution, estimated at around 80%, originates from land-based sources, entering the ocean via rivers, runoff, and atmospheric deposition.
Ocean acidification negatively impacts marine life by:
Answer: Hindering the growth of organisms with shells or skeletons.
Explanation: Ocean acidification reduces the availability of carbonate ions, making it more difficult for marine organisms like corals and mollusks to build and maintain their shells and skeletons.
Which pathway is a significant source of invasive species in marine ecosystems?
Answer: Ballast water transport in ships.
Explanation: The transport of ballast water by ships is a major pathway for the introduction of non-native, invasive species into marine ecosystems worldwide.
Which of the following is a consequence of ocean acidification mentioned in the text?
Answer: Lowered calcification rates for marine organisms.
Explanation: Ocean acidification impedes the ability of marine organisms, particularly those with calcium carbonate structures, to calcify, thereby lowering their growth and survival rates.
Large Marine Ecosystems (LMEs) were identified to facilitate environmental conservation and ecosystem-based management, not solely fish stock management.
Answer: True
Explanation: Large Marine Ecosystems were conceptualized by NOAA to support broader goals of conservation and ecosystem-based management, extending beyond just fisheries management.
Large Marine Ecosystems contribute significantly to the global economy, estimated in the trillions of dollars annually.
Answer: True
Explanation: Large Marine Ecosystems are economically vital, contributing an estimated $3 trillion annually and supporting a substantial portion of global fisheries.
Assessing Large Marine Ecosystems involves multiple key modules, including productivity, pollution, socioeconomics, and governance, not just productivity.
Answer: True
Explanation: The assessment framework for Large Marine Ecosystems comprises five key modules: productivity, fish and fisheries, pollution and ecosystem health, socioeconomics, and governance.
Sustainable Development Goal 14 ('Life Below Water') focuses on conserving and sustainably using oceans and marine resources.
Answer: True
Explanation: Sustainable Development Goal 14 is dedicated to the conservation and sustainable utilization of oceans, seas, and marine resources for sustainable development.
Marine protected areas (MPAs) can help kelp forests by reducing overgrazing from herbivores.
Answer: True
Explanation: By limiting fishing activities, Marine Protected Areas can help manage herbivore populations, thereby reducing grazing pressure on kelp forests and aiding their recovery.
Marine protected areas (MPAs) primarily aim to conserve biodiversity and ecosystem health, not necessarily to increase fishing yields within their boundaries.
Answer: True
Explanation: The primary objective of Marine Protected Areas is the conservation of marine biodiversity and ecosystems, although spillover effects can sometimes benefit surrounding fisheries.
Large Marine Ecosystems (LMEs) are typically larger than 200,000 square kilometers.
Answer: True
Explanation: Large Marine Ecosystems are generally defined as oceanic regions exceeding 200,000 square kilometers, encompassing significant ecological and biogeochemical processes.
NOAA identified Large Marine Ecosystems (LMEs) primarily for:
Answer: Facilitating environmental conservation and ecosystem-based management.
Explanation: The identification of Large Marine Ecosystems by NOAA was intended to advance environmental conservation efforts and promote ecosystem-based management strategies.
What is the estimated annual economic contribution of Large Marine Ecosystems?
Answer: $3 trillion
Explanation: Large Marine Ecosystems contribute an estimated $3 trillion annually to the global economy, highlighting their immense economic significance.
Which of the following is NOT one of the five key modules used to assess Large Marine Ecosystems?
Answer: Climate change impacts
Explanation: The five key modules for assessing LMEs are productivity, fish and fisheries, pollution and ecosystem health, socioeconomics, and governance. Climate change impacts are a critical factor but not listed as one of the five core assessment modules.
What is the main goal of Sustainable Development Goal 14 ('Life Below Water')?
Answer: To conserve and sustainably use oceans and marine resources.
Explanation: Sustainable Development Goal 14 explicitly aims to conserve and sustainably utilize the world's oceans, seas, and marine resources to promote sustainable development.
Marine protected areas (MPAs) help conserve biodiversity primarily by:
Answer: Restricting human activities like fishing.
Explanation: MPAs conserve biodiversity by limiting or prohibiting human activities, particularly fishing, which allows marine populations and habitats to recover and thrive.