Hudson River Geography Overview

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Questions and Answers

What is the elevation of Lake Tear of the Clouds, the source of the Hudson River?

6,000 feet

4,000 feet

5,000 feet

5,344 feet (correct)

What is the length of the Upper Hudson River segment?

160 miles (correct)

120 miles

153 miles

200 miles

What type of climate is experienced in the Hudson River watershed?

Polar climate with extreme cold

Cold winters and warm summers (correct)

Tropical climate with high humidity

Arid climate with little precipitation

Which factor does NOT affect the climate in the Hudson River watershed?

Presence of forests Signup and view all the answers

What is the specific heat capacity of water?

4.18 J/g °C Signup and view all the answers

What is characteristic of the lower Hudson River estuary?

It has brackish water due to the mixture of fresh and salty water Signup and view all the answers

How does moist air differ from dry air regarding temperature changes?

Moist air has a higher specific heat capacity than dry air Signup and view all the answers

What primarily demarcates the upper and lower Hudson River?

The Federal Dam at Troy Signup and view all the answers

What is the primary factor that causes saltwater to be denser than freshwater?

Higher salinity Signup and view all the answers

What is the definition of the salt front in the river?

The leading edge of saltwater flooding the river Signup and view all the answers

Which of the following statements about thermal stratification is true?

Cold water is denser and sinks below warm water Signup and view all the answers

How has the dissolved oxygen (DO) levels in the Hudson River changed compared to decades ago?

DO levels are now much better due to regulations Signup and view all the answers

Why is oxygen content in water critical for aquatic organisms?

It supports their metabolic processes Signup and view all the answers

What concentration level defines the salt front in terms of chloride concentration?

100 mg/L Signup and view all the answers

What impact does temperature have on dissolved oxygen levels in water?

Cold water holds more oxygen than warm water Signup and view all the answers

What was the NYS Water Quality Standard for dissolved oxygen in the Hudson River Estuary?

4 mg/L Signup and view all the answers

What explains why water moderates Earth's climate more effectively than air when heat is added?

Water can absorb more heat without a significant rise in temperature. Signup and view all the answers

During which stage does the current in the Hudson Estuary switch from flooding to ebbing?

Slack Signup and view all the answers

Why do locations on Earth experience two high tides and two low tides each day?

Earth's rotation allows a location to align with the Moon twice. Signup and view all the answers

What causes spring tides in the ocean?

The Sun pulls on the ocean water parallel with the Moon. Signup and view all the answers

How is salinity measured in the Hudson River?

Parts per thousand (PPT) Signup and view all the answers

Why does salinity in the Hudson River vary from 2 to 20 g/L?

It is influenced by rainfall and freshwater input. Signup and view all the answers

What is a knot in terms of measuring current speed?

1.15 miles per hour Signup and view all the answers

How does the alignment of a location with the Moon affect tidal levels?

Alignment leads to higher high tides. Signup and view all the answers

What role do oysters play in the Hudson Estuary?

They act as filter-feeders and build reefs. Signup and view all the answers

Which of the following statements about estuaries is accurate?

Estuaries are vital for migratory bird populations. Signup and view all the answers

What is a primary characteristic of anadromous fish?

They reproduce in freshwater but spend most of their life in the sea. Signup and view all the answers

What are phytoplankton's role in the food web of the Hudson?

They are the primary producers. Signup and view all the answers

Which of the following is NOT a function of estuarine habitats?

Exclusively providing habitat for birds. Signup and view all the answers

Which of the following crustaceans is mentioned as predominant in the Hudson?

Blue crab Signup and view all the answers

What significant ecological service do oyster reefs provide?

They increase species richness and biodiversity. Signup and view all the answers

Which fish species is categorized as catadromous?

American eel Signup and view all the answers

What are the main sources of Dissolved Organic Matter (DOM) in the Hudson River?

Watershed soils, decomposition in the river, and pollution Signup and view all the answers

What are the primary environmental threats to estuaries mentioned?

Nutrient runoff and pollutants from agriculture Signup and view all the answers

What does the Clean Water Act of 1972 primarily aim to regulate?

Discharges of pollutants into navigable waters Signup and view all the answers

Which of the following is NOT a way that estuaries provide ecological value?

Generating electricity through tidal power Signup and view all the answers

What role does the spongy matrix of peat play in salt marshes?

It filters pollutants from water as it flows through. Signup and view all the answers

Which of the following is an example of a point source of pollution?

Sewage discharge from a treatment plant Signup and view all the answers

What is one of the roles of DOM in aquatic ecosystems?

It acts as food for bacteria and supports the food chain. Signup and view all the answers

Which of the following pollution sources can lead to combined sewer overflows (CSOs)?

Urban and stormwater runoff Signup and view all the answers

Study Notes

Hudson River Overview

Source: Lake Tear of the Clouds on Mount Marcy (elevation 5,344 feet, Adirondack Mountains)
Mouth: The Battery, New York Harbor
Upper Hudson River flows 160 miles from Lake Tear of the Clouds to the Federal Dam at Troy, dropping over 4,300 feet in elevation
Lower Hudson River extends 153 miles from Troy Dam to New York City; minimal elevation drop

Hudson River Estuary

Estuary: Where fresh water from rivers meets salty seawater, characterized by brackish water
The lower Hudson Estuary spans from Battery at Manhattan to Stony Point in Haverstraw Bay
Watershed area: 13,326 square miles, affecting water quality through runoff

Climate Influences

Cold winters and warm summers; precipitation is evenly distributed
Climate factors:
- Elevation affects temperature: higher altitudes have cooler temperatures
- Latitude impacts solar energy intensity, causing temperature variation from equator to poles
- Proximity to ocean moderates temperature due to moist air

Specific Heat Capacity

Water: high specific heat capacity (4.18 J/g°C) slows temperature change
Dry air: lower specific heat capacity (1.00 J/g°C), heating and cooling quickly

Tides and Currents

The Hudson Estuary is tidal, influenced by the Atlantic Ocean
Two high tides and two low tides daily due to Earth's rotation and moon's gravitational pull
Tidal terms: Flood (ocean water flows upstream), Ebb (water flows downstream), Slack (current switches)
Speed of current measured in knots: 1 knot = 1.15 miles per hour

Salinity and Water Density

Salinity of Hudson varies from 2 to 20 g/L; ocean average is about 35 g/L
Salinity influences water density: saltwater (denser than freshwater) forms a "salt wedge" during mixing
Thermal stratification is not common in Hudson, but cold water is denser than warm water

Dissolved Oxygen (DO)

DO levels in the Hudson range from 8 to 14 mg/L, with 4 mg/L as the minimum standard for aquatic life
Critical factors for DO levels include photosynthesis, respiration, and atmospheric exchange
The Clean Water Act of 1972 significantly improved water quality compared to historical lows (4 mg/L or less)

Suspended Sediment and Pollution

DOM (Dissolved Organic Matter) is crucial for food webs but can carry pollutants
Pollution sources affecting water quality in the Lower Hudson include municipal wastewater, CSOs, agricultural runoff, and urban runoff
The Clean Water Act regulates discharges of pollutants and sets standards for surface water quality

Ecological Value of Estuaries

Estuaries filter pollutants through salt marshes, improving water quality and nutrient availability for ecosystems
Serve as buffer zones, mitigating flood and erosion impacts
Support diverse habitats for various species, including fish populations and migratory birds

Hudson River Food Web

Phytoplankton serve as primary producers; shellfish and various crustaceans are vital for the ecosystem
Oysters are keystone species, providing essential ecosystem functions:
- Filter feeding leads to cleaner water and supports other marine life
- Create natural reefs, enhancing habitat and biodiversity

Fish Species

Anadromous fish (e.g., shad, striped bass) spawn in freshwater but live mostly in the sea
Catadromous fish (e.g., American eel, bluefish) spawn in saltwater while living in freshwater

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Description

Explore the geographical features and course of the Hudson River, from its source at Lake Tear of the Clouds to its mouth at The Battery in New York Harbor. This quiz covers both the upper and lower segments of the river and includes elevation changes.