Marine Ecosystems and Climate Change

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Questions and Answers

What is a significant role played by diatoms in the ecosystem?

They directly feed on benthic animals.

They are responsible for a large part of primary production. (correct)

They fix nitrogen in the soil.

They provide oxygen through photosynthesis.

Which organisms are primarily dominant in the Hudson nekton community?

Crustaceans

Aquatic plants

Mollusks

Fish (correct)

Which of the following is NOT a service provided by oyster reefs?

Water filtration.

Habitat for adult marine mammals. (correct)

Protection for juvenile fish.

Food for some marine species.

What do copepods primarily feed on?

Phytoplankton. Signup and view all the answers

How does the proposed flood risk solution for NYC differ from that of London?

NYC uses movable gates; London uses permanent barriers. Signup and view all the answers

What is a potential negative impact of harbor gates in the Hudson River?

They would require precise coordination during storms. Signup and view all the answers

What essential nutrient do diatoms require to survive?

Dissolved silicon Signup and view all the answers

Which aspect of oyster reefs is crucial for marine habitats?

They provide shelter and feeding areas. Signup and view all the answers

What role do plankton play in the marine food web?

They are producers that undergo photosynthesis. Signup and view all the answers

How does warming water potentially affect plankton?

It could lead to a decline in plankton populations. Signup and view all the answers

What competition exists among algae in coral reefs?

Red algae dominate and outcompete coralline algae for space. Signup and view all the answers

What is a consequence of the dominance of peyssonneliaceae algae on coral reefs?

They smother corals and hinder coral regeneration. Signup and view all the answers

What distinguishes coralline algae from peyssonneliaceae algae?

Coralline algae are typically eaten by fish, unlike peyssonneliaceae. Signup and view all the answers

What is the primary issue caused by red algae in coral reefs?

They compete with coralline algae for resources. Signup and view all the answers

What phenomenon does the title 'A River that Flows Both Ways' refer to?

The mixing of freshwater and saltwater in an estuary. Signup and view all the answers

What is a partially mixed estuary?

An estuary with distinct layers of salt and freshwater. Signup and view all the answers

What is the typical time interval between high tides?

12 hours and 25 minutes Signup and view all the answers

How does increased salinity affect dissolved oxygen levels in seawater compared to freshwater?

Decreases oxygen solubility Signup and view all the answers

What is a common human activity that leads to decreased dissolved oxygen levels in the river?

Dumping organic waste into the river Signup and view all the answers

What three factors control the concentration of dissolved oxygen in the river?

Respiration and photosynthesis, atmospheric exchange, and water movements Signup and view all the answers

What is the primary role of dissolved organic matter (DOM) in aquatic ecosystems?

Acting as a primary food source for aquatic bacteria Signup and view all the answers

Which of the following correctly describes plankton?

Microscopic organisms that contain chlorophyll and form the base of the food web Signup and view all the answers

What is the main difference between plankton and nekton?

Plankton are primarily composed of microscopic organisms while nekton are larger and swim actively Signup and view all the answers

What process is responsible for the depletion of dissolved oxygen in aquatic environments?

Aerobic respiration Signup and view all the answers

Which layer of water is typically saltier in the part of the river between the Verrazano Narrows and the George Washington Bridge?

The saline bottom layer Signup and view all the answers

What characteristic distinguishes the Hudson River near Albany compared to the section between the Verrazano Narrows and the George Washington Bridge?

Lower salinity due to upstream freshwater dominance Signup and view all the answers

What type of tides occur when the sun and moon align with each other?

Spring tides Signup and view all the answers

What occurs during neap tides due to the positioning of the sun and moon?

Partial cancellation of gravitational effects Signup and view all the answers

How does wind and tide affect salinity in the estuarine section of the river?

They mix the freshwater and saltwater layers Signup and view all the answers

Which phase of the moon results in spring tides?

New moon and full moon Signup and view all the answers

What does stratification refer to in the context of the Hudson River's salinity?

The alternating layers of fresh and saline water Signup and view all the answers

Why do lunar tides have a greater influence than solar tides?

The moon is significantly closer to Earth Signup and view all the answers

What process is used to inactivate viruses and bacteria in the samples?

Placing in a hot-water bath for an hour Signup and view all the answers

How much of the Earth's land surface is covered by grassland ecosystems?

Approximately 40.5% Signup and view all the answers

What percentage of the global terrestrial carbon stocks is stored by grasslands?

Approximately one third Signup and view all the answers

Which of the following contributes to the ecosystem services provided by grasslands?

Soil erosion prevention Signup and view all the answers

What is the primary location of carbon storage in grasslands?

Below ground as root biomass and soil organic carbon Signup and view all the answers

How much net primary productivity in grassland ecosystems is allocated belowground?

About 60% Signup and view all the answers

What factor contributes to the decline in local menhaden stocks?

Overfishing Signup and view all the answers

Which species is NOT mentioned as being affected by the decline of menhaden stocks?

Tuna Signup and view all the answers

Study Notes

Plankton and the Marine Food Web

Plankton are producers in the marine food web, undergoing photosynthesis and forming the base of the food web.
Plankton are severely affected by warming waters and ocean acidification.
Changes in plankton populations impact ecosystem functioning, biomass production, and food web productivity.

Climate Change and Reef Health

Coralline algae form crusts on reefs and promote coral growth.
Peyssonneliaceae algae can outcompete coralline algae forming thick, brown, or dark red crusts, smothering corals and preventing regeneration.
Warming waters or other climate change impacts may be driving the expansion of peyssonneliaceae algae.
Competition between red algae and coralline algae is a key example of interspecific interaction.

The Hudson River

The Hudson River is an estuary, where freshwater and saltwater mix.
The river exhibits a salinity gradient, with freshwater at its source and higher salinity near the Atlantic Ocean.
The New York Harbor, between Verrazano Narrows and George Washington Bridge, shows a distinct two-layer vertical structure with a saline bottom layer and a freshwater surface lens.
The moon has a greater influence on tides than the sun due to its closer proximity.
Spring tides occur when the sun and moon align, resulting in strong tidal forces.
Neap tides occur when the sun and moon are perpendicular, producing weaker tidal forces.
The Hudson River doesn't stratify thermally but can stratify due to saltwater intrusions.
Dissolved oxygen concentrations in the Hudson River typically range from 0 to 15 mg/L.
The concentration of dissolved oxygen in the river is influenced by respiration, photosynthesis, and water movement.
Organic waste dumping can deplete dissolved oxygen levels in the river, harming aquatic life.
Aerobic respiration consumes significant amounts of oxygen.

Hudson River Ecosystem

Plankton are microscopic organisms, crucial for the river's food web.
Diatoms, a type of phytoplankton, are a major contributor to primary production and a food source for zooplankton and benthic animals.
Copepods are large zooplankton that feed on phytoplankton and are a key food source for fish.
Nekton, predominantly fish, are an important component of the Hudson River's ecosystem.
Blue crabs are also present in the river, contributing to the nekton community.
Oyster reefs provide habitat, food, and protection for various marine species, contributing to ecosystem services.

Flood Risk Management

Urban areas like New York City and London have adopted flood-risk mitigation strategies.
New York City's proposal for floodwalls and levees is less flexible than London's movable gate system.
Harbor gates, while effective, could disrupt public access and connection to the water in New York City.

Fishing Quotas

Fishing quotas are crucial for maintaining the health of fish populations.
Overfishing can disrupt the ecological balance of coastal waters, affecting larger fish, marine mammals, and birds that rely on smaller fish species.
The decline in menhaden populations, a vital food source for various species, highlights the importance of sustainable fishing practices.

Grassland Ecosystems

Grasslands occupy approximately 40.5% of the Earth's land surface.
They store about one-third of the global terrestrial carbon stocks, with 90% of their carbon stored below ground as root biomass and soil organic carbon.
Grasslands are essential for diverse ecosystem services, including carbon sequestration, soil health, biodiversity, and water regulation.

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Description

Explore the intricate relationships within marine ecosystems, focusing on plankton, coralline algae, and their responses to climate change. Understand how these interactions affect the marine food web and the health of estuaries like the Hudson River. This quiz covers key concepts relevant to marine biology and ecology.