Introduction to Marine Biology: Estuaries & Mangroves

These flashcards cover key concepts from the Marine Biology lecture on estuaries and mangroves, including definitions, ecological significance, and adaptations of organisms in these environments.

What is an estuary?

A semi-enclosed coastal body of water that has free connection to the open seas and is measurably diluted with freshwater.

Why are estuaries important?

They are scientifically fascinating because they represent a unique ecosystem where fresh and salt water mix, supporting diverse organisms.

What factors threaten estuaries?

Human activities leading to degradation, such as urban development and pollution.

What is the tidal influence on estuaries?

Tides create an intertidal zone which exposes organisms to air, leading to stress from desiccation.

What are mangroves?

Woody trees or shrubs that thrive at the sea/land interface in tropical estuaries and inlets, forming a unique habitat known as mangal.

Where are mangroves typically found?

Within the 20°C isotherm and are replaced by salt marshes at higher latitudes.

What are the three types of mangrove forests?

Riverine, tide-dominated, and basin mangroves.

How do mangrove trees survive in waterlogged sediments?

They have specialized roots, such as knee roots and aerial roots, that provide oxygen and stability.

How do mangroves deal with salt?

They either exclude salt through their roots, tolerate it in tissue, or secrete excess salt.

What is the significance of propagules in mangrove reproduction?

They remain attached to the parent plant and develop into seedlings before being dispersed into water.

Why are mangroves critical to coastal protection?

They reduce damage from storms and waves by acting as natural barriers.

How do mangroves contribute to marine productivity?

They export leaf litter which adds significant carbon to the oceans, representing a portion of terrestrial carbon.

What role do mangroves play for coral reefs?

They protect reefs from coastal runoff and serve as nursery grounds for reef fish.

What adaptations do organisms in estuaries exhibit due to variable conditions?

Organisms possess physiological and behavioral adaptations to cope with factors like salinity, tide, and sediment.

What is meant by a 'salt wedge' estuary?

A estuary where salt water from the sea forms a wedge that does not mix easily with the freshwater from rivers.