Rocky Intertidal Zonation | Oceanography

Summary

This video explores intertidal zonation on rocky shores, detailing the distinct zones from the spray zone to the lower intertidal zone. Each zone is characterized by varying physical and biological stresses, influencing the diversity and distribution of marine organisms. The spray zone, largely dry, hosts resilient species like barnacles and limpets, while the upper and middle intertidal zones see increased competition and predation. The lower intertidal zone, rich in diversity, is predominantly submerged, featuring organisms such as sea stars and small fish. The sub-tidal zone, rarely exposed, supports larger predators. Understanding these zones highlights the intricate balance of marine ecosystems.

Takeaways

• 🌊 The intertidal zone is the area on the shore that is exposed at low tide and submerged at high tide.
• 🗺️ Rocky shores feature horizontal zonation of species due to the solid surface for attachment.
• 🌿 The intertidal zone is divided into four main areas: spray zone, upper intertidal, mid intertidal, and lower intertidal, with the sub-tidal zone below.
• ☀️ Organisms in the spray zone experience high physical stress due to desiccation and temperature fluctuations, leading to sparse populations.
• 🐚 The upper intertidal zone has more diverse species than the spray zone and is dominated by barnacles, periwinkles, and limpets.
• 🌊 The middle intertidal zone is regularly submerged, leading to greater diversity and increased competition among species.
• 🦪 Mussels and barnacles compete for space in the middle intertidal zone, influencing their distribution based on their ability to cope with desiccation.
• 🐠 The lower intertidal zone is usually submerged and hosts a wide variety of organisms, including algae, fish, and invertebrates.
• 🌱 Brown algae are a key feature of the lower intertidal zone, indicating its rich biodiversity.
• 🦑 The sub-tidal zone is rarely exposed and serves as a habitat for predator species like octopus and larger fish.

Q & A

What is the intertidal zone?

The intertidal zone is the area along the seashore that is exposed at low tide and submerged at high tide.

How does the intertidal zone differ from other habitats?

The intertidal zone varies significantly from other habitats like sandy beaches or mangrove swamps due to its solid surface and unique biological and physical stresses.

What are the four general zones of the rocky intertidal?

The rocky intertidal can be divided into the spray zone, upper intertidal zone, mid intertidal zone, and lower intertidal zone.

What factors determine the upper and lower limits of organisms in the intertidal zone?

The upper limit is generally determined by physical stresses like desiccation and temperature fluctuations, while the lower limit is influenced by biological factors such as predation and competition.

What organisms are typically found in the spray zone?

The spray zone is home to organisms like barnacles, limpets, and periwinkles, which possess protective coverings to prevent desiccation.

Why is the upper intertidal zone more diverse than the spray zone?

The upper intertidal zone experiences more competition and predation, leading to a higher diversity of species, including barnacles, periwinkles, and algae.

How does the middle intertidal zone differ from the upper intertidal zone?

The middle intertidal zone is regularly submerged, has more time underwater, resulting in higher species diversity and less exposure to desiccation than the upper intertidal zone.

What role do mussels play in the competitive dynamics of the middle intertidal zone?

Mussels can suffocate barnacles beneath them, thereby limiting barnacles' ability to occupy the same space, influencing their distribution within the middle intertidal zone.

What characterizes the lower intertidal zone?

The lower intertidal zone is usually submerged and hosts a diverse array of organisms, such as small fish and various types of algae, with fewer physical stresses.

What organisms can be found in the sub-tidal zone?

The sub-tidal zone, rarely exposed, contains predator species like octopuses and larger fish that prey on organisms in the lower intertidal zone.