Marine science Midterm

How many oceans are on Earth?

There are five oceans on Earth: the Pacific, Atlantic, Indian, Southern (or Antarctic), and Arctic Oceans.

Is the number of oceans going to change in the future? Explain.

The number of oceans is not expected to change significantly in the future, as oceanic boundaries are defined by geological and geographical factors that are stable over human timescales.

Why do we say that marine science is an interdisciplinary science?

Marine science is interdisciplinary because it integrates knowledge from various fields such as biology, chemistry, geology, meteorology, and physics to study ocean systems and marine life.

What are the origins of oceans?

One of the most accepted theories states that oceans originated from water delivered by comets and asteroids and from water released from Earth's interior through volcanic outgassing.

Who were the first people to explore the oceans? Why?

The first people to explore the oceans were likely ancient civilizations such as the Polynesians and Greeks, who navigated for trade, fishing, and exploration.

What significant technologies or individuals have contributed to our understanding of the marine environment?

Significant contributors include Aristotle (the first marine biologist), Ferdinand Magellan (first to sail around the world), James Cook (scientific observations during voyages), Jacques Cousteau (pioneered deep-sea exploration), and modern technologies like satellites, ROVs, and AUVs.

What is salinity?

Salinity is the total amount of dissolved salts in seawater, usually measured in parts per thousand (ppt), with an average salinity of about 35 ppt.

What are the sources of salts in ocean water?

Sources of salts include weathering and erosion of continental rocks, hydrothermal vents on the seafloor, and volcanic emissions.

What factors increase salinity?

Factors that increase salinity include high evaporation, low precipitation, and restricted circulation.

What factors decrease salinity?

Factors that decrease salinity include rainfall, river runoff, and melting sea ice.

What is the thermocline?

The thermocline is a layer in the ocean where temperature decreases rapidly with depth.

What is density stratification in ocean water?

Density stratification refers to the layering of ocean water, where density increases with higher salinity and lower temperature.

What are the three major marine life zones based on distance from shore?

The three major marine life zones are the intertidal zone, the neritic zone, and the oceanic zone.

What are phytoplankton?

Phytoplankton are microscopic plants and algae that serve as primary producers in the ocean.

What are zooplankton?

Zooplankton are animal plankton, many of which are larvae of fish, crabs, and corals.

What are nekton?

Nekton are strong swimmers capable of moving independently of currents, including fish, sharks, squid, marine mammals, and sea turtles.

What are benthos?

Benthos are organisms that live on, in, or near the seafloor, including both sessile organisms like corals and mobile organisms like crabs.

What is ocean productivity?

Ocean productivity refers to the amount of biomass produced by photosynthetic organisms, primarily phytoplankton.

What is primary productivity?

Primary productivity is the production of organic compounds from inorganic compounds through photosynthesis or chemosynthesis.

What factors affect ocean productivity?

Factors affecting ocean productivity include light availability, nutrient levels, and temperature.

What are surface currents?

Surface currents are ocean currents driven by wind patterns, Earth's rotation, and continental boundaries, creating large circular systems called gyres.

What is thermohaline circulation?

Thermohaline circulation is the deep ocean current driven by differences in temperature and salinity, often referred to as the global conveyor belt.

What is upwelling?

Upwelling is the process where deep, nutrient-rich water rises to the surface, supporting highly productive ecosystems.

What is an ecosystem?

An ecosystem is a community of interacting organisms and their physical environment.

What are trophic levels?

Trophic levels are the hierarchical levels in an ecosystem, consisting of primary producers, primary consumers, secondary consumers, tertiary consumers, and apex predators.

What is marine snow?

Marine snow refers to falling organic particles in the ocean that provide food for organisms living below the photic zone.

What are the environmental challenges facing the open ocean?

Environmental challenges include climate change, ocean acidification, deoxygenation, pollution, and overfishing.

Why does the open ocean matter?

The open ocean regulates climate, absorbs heat and CO₂, produces oxygen, supports fisheries and biodiversity, and is home to unique species and ecosystems.

What is an estuary?

An estuary is a partially enclosed coastal body of water where freshwater from rivers mixes with saltwater from the ocean.

What is brackish water?

Brackish water is a mixture of fresh and salt water, typically found in estuaries.

What are the key features of estuaries?

Estuaries have brackish water, low energy environments, rich sediments, and serve as nursery habitats for juvenile fish and shellfish.

Why do estuaries matter?

Estuaries are important for high biodiversity, high primary productivity, supporting major fisheries, and providing ecosystem services such as storm protection, water filtration, carbon storage, and recreation.

What contributes to the high productivity of estuaries?

Flooding brings nutrients from rivers and the ocean, sunlight penetrates shallow water, and plants like phytoplankton and seagrass perform rapid photosynthesis.

What is the Chesapeake Bay?

The Chesapeake Bay is the largest estuary in the United States, located in the Mid-Atlantic region.

What are the physical and biological characteristics of the Chesapeake Bay?

The Chesapeake Bay has a brackish gradient, over 3,600 species of plants and animals, and critical habitats such as salt marshes, seagrass beds, oyster reefs, and tidal wetlands.

What are some key species in the Chesapeake Bay?

Key species include blue crab, eastern oyster, striped bass (rockfish), and submerged aquatic vegetation like eelgrass.

What is nutrient pollution?

Nutrient pollution, primarily from nitrogen and phosphorus, is the number one environmental challenge for the Chesapeake Bay, often caused by agriculture, CAFOs, urban stormwater, and wastewater treatment plants.

What are CAFOs?

CAFOs (Concentrated Animal Feeding Operations) are large industrial farms that raise animals like chickens, pigs, and cattle in high densities for rapid production.

What problems are caused by CAFO manure?

Problems include excess nutrients leading to runoff, eutrophication and algal blooms, hypoxia (low oxygen), pathogens, and air pollution from nitrogen deposition.

What are the main threats to coral reefs?

Threats include climate change, pollution, overfishing, habitat destruction, and diseases.

What are coral reefs?

Coral reefs are underwater ecosystems that are home to about 25% of all marine fish species, despite covering less than 1% of the Earth's surface.

What are corals made of?

Corals are made of soft-bodied animal polyps, a hard external skeleton of calcium carbonate, and photosynthetic algae called zooxanthellae.

What are the types of corals?

Types of corals include hard (stony) corals, which build the reef framework, and soft corals, which are flexible and do not produce hard skeletons.

Where are coral reefs found?

Coral reefs are mostly found in warm, shallow, tropical waters that require sunlight, stable salinity, and clear water.

What are the key reef types?

Key reef types include fringing reefs, barrier reefs, and atolls.

What is the mutualistic relationship between corals and zooxanthellae?

Zooxanthellae provide food, bright colors, oxygen, and nutrients to corals, while corals provide a protected environment and carbon dioxide for photosynthesis.

Why is biodiversity high in coral reefs?

Biodiversity is high due to structural complexity, abundant food from primary production, and diverse ecological niches.

What ecosystem services do coral reefs provide?

Coral reefs provide nursery habitats for fish, coastal protection, support for tourism and fisheries, and contribute to carbon and nutrient cycling.

What is coral bleaching?

Coral bleaching is a stress response where corals expel their zooxanthellae, often due to warming waters.

What are the major river inputs to the Chesapeake Bay?

Major river inputs include the Susquehanna, Potomac, James, Rappahannock, and York rivers.

What is the Chesapeake Bay Program?

The Chesapeake Bay Program is a partnership among states and federal agencies aimed at reducing nutrient pollution, restoring oyster reefs, expanding seagrass beds, reconnecting rivers, and protecting wetlands.

What is hypoxia in the context of estuaries?

Hypoxia refers to low oxygen levels in water, often caused by algal blooms that deplete oxygen when they die and decompose.

What are the critical habitats found in the Chesapeake Bay?

Critical habitats include salt marshes, seagrass beds, oyster reefs, and tidal wetlands.

What is the ecological role of coral reefs?

Coral reefs play a crucial role in providing habitat, supporting biodiversity, and maintaining ecological balance in marine ecosystems.

What causes coral bleaching?

Coral bleaching can be caused by elevated water temperatures, pollution, changes in salinity, and high UV radiation.

What are the effects of coral bleaching?

The effects include loss of color, reduced energy, and increased risk of death for coral.

What is the Great Barrier Reef?

The Great Barrier Reef is the world's largest coral reef system, stretching over 2,300 km, and is home to over 600 coral species and 1,500 fish species.

What challenges does the Great Barrier Reef face?

Challenges include repeated mass bleaching events, cyclone damage, and crown-of-thorns starfish outbreaks.

What are coral nurseries?

Coral nurseries are restoration efforts that involve growing coral in controlled environments to help restore damaged reefs.

What is assisted evolution in coral restoration?

Assisted evolution involves breeding heat-resilient coral strains to enhance their survival in changing ocean conditions.

What are waves?

Waves are movements of energy through water caused mainly by wind, where water moves in a circular motion but does not travel with the wave.

What is a crest in a wave?

The crest is the highest point of a wave.

What is a trough in a wave?

The trough is the lowest point of a wave.

What is wavelength?

Wavelength is the distance between two crests or two troughs of a wave.

What is wave height?

Wave height is the vertical distance between a crest and a trough.

What is amplitude in waves?

Amplitude is half of the wave height.

What is wave period?

Wave period is the time it takes for two crests to pass through a fixed point.

What causes waves?

Waves are primarily caused by wind, but can also be caused by underwater earthquakes or landslides, and the gravitational pull of celestial bodies.

What are tides?

Tides are the regular rise and fall of sea level caused by the gravitational pull of the Moon and the Sun on Earth's oceans.

What is a high tide?

High tide is when the water level rises to its highest point.

What is a low tide?

Low tide is when the water level falls to its lowest point.

What are spring tides?

Spring tides occur during full and new moons, resulting in the highest high tides and lowest low tides.

What are neap tides?

Neap tides occur during the first and third quarter moons, resulting in the least difference between high and low tides.

What are ocean currents?

Ocean currents are continuous movements of ocean water driven by wind, temperature, salinity, and Earth's rotation.

What are deep currents?

Deep currents are ocean currents caused by differences in water density, driven by temperature and salinity.

What is the Gulf Stream?

The Gulf Stream is a warm ocean current that flows north along the U.S. east coast.

What is the California Current?

The California Current is a cold ocean current that flows south along the U.S. west coast.

What is the role of ocean currents?

Ocean currents distribute heat around the planet, help with nutrient cycling, and affect navigation, weather patterns, and fishing industries.

What are the main characteristics of fish?

Fish are aquatic vertebrates with gills for gas exchange, fins for swimming, scales for protection, and a streamlined body for efficient movement.

What are bony fish?

Bony fish, or Osteichthyes, are the largest and most diverse group of fish, including species like salmon and tuna.

What are cartilaginous fish?

Cartilaginous fish, or Chondrichthyes, include sharks, rays, and skates, characterized by a skeleton made of cartilage.

What is the function of fish fins?

Fins help fish move, balance, and steer in the water.

What is the swim bladder?

The swim bladder is an organ in most bony fish that controls buoyancy, allowing them to rise or sink without expending much energy.