Coastal Ecosystems » Biotic Characteristics of Coastal Ecosystems

What you'll learn this session

Study time: 30 minutes

Understand what biotic characteristics are and why they matter in coastal ecosystems
Explore the different types of organisms found in coastal environments
Learn about food webs and energy flow in coastal ecosystems
Discover how organisms adapt to coastal conditions
Examine human impacts on coastal wildlife
Study real-world examples from UK coastal areas

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Introduction to Biotic Characteristics of Coastal Ecosystems

Coastal ecosystems are some of the most diverse and productive environments on Earth. The biotic characteristics refer to all the living components - from tiny bacteria to large marine mammals. These organisms have evolved amazing adaptations to survive in the challenging conditions where land meets sea.

Understanding biotic characteristics helps us appreciate the complexity of coastal life and why these ecosystems are so important for biodiversity and human communities.

Key Definitions:

Biotic: All living components of an ecosystem, including plants, animals and microorganisms.
Ecosystem: A community of living organisms interacting with their physical environment.
Biodiversity: The variety of life in all its forms within a particular habitat.
Adaptation: Special features that help organisms survive in their environment.

🌊 Primary Producers

These are the foundation of coastal food webs. Seaweeds, salt marsh grasses and phytoplankton use sunlight to make food through photosynthesis. They provide energy for all other organisms in the ecosystem.

🐟 Primary Consumers

These herbivores feed directly on plants. Examples include limpets scraping algae from rocks, sea urchins grazing on kelp and small fish eating phytoplankton.

Types of Coastal Organisms

Coastal ecosystems support an incredible variety of life forms, each adapted to specific conditions. From the splash zone to the deep subtidal areas, different organisms dominate different zones.

Marine Plants and Algae

These photosynthetic organisms form the base of most coastal food webs. They range from microscopic phytoplankton to massive kelp forests.

🌱 Seaweeds

Brown, red and green algae that attach to rocks. Kelp can grow up to 60cm per day and creates underwater forests.

🌿 Salt Marsh Plants

Specially adapted grasses and herbs that can tolerate salt water. Spartina grass is common in UK salt marshes.

🐟 Phytoplankton

Microscopic floating plants that form the base of marine food chains. They produce much of the world's oxygen.

Invertebrates

These animals without backbones make up the majority of coastal species. They've developed remarkable adaptations to survive crashing waves, changing tides and varying salinity.

Rocky Shore Specialists:

Barnacles: Cement themselves to rocks and filter feed when covered by water
Mussels: Use strong threads to attach to rocks and filter plankton from water
Limpets: Cone-shaped shells that clamp tightly to rocks to avoid being washed away
Sea anemones: Soft-bodied predators that retract into crevices when exposed

Case Study Focus: The Severn Estuary

The Severn Estuary supports over 70,000 wintering birds including curlews, dunlin and shelducks. Its mudflats are rich in invertebrates like ragworms and cockles. The estuary's biotic characteristics change dramatically with the 14-metre tidal range - one of the largest in the world. This creates diverse habitats from saltmarsh to mudflats, each supporting different communities of organisms.

Vertebrates in Coastal Ecosystems

Fish, birds and marine mammals are the most visible vertebrates in coastal areas. They often migrate between different coastal habitats and play crucial roles as predators and prey.

Fish Communities

Coastal waters support both resident species and those that visit during migration or breeding. Many commercially important fish depend on coastal nursery areas.

🐟 Resident Species

Blennies, gobies and wrasse live permanently in coastal waters. They're often small and well-camouflaged to hide from predators.

🐟 Migratory Species

Salmon, sea trout and bass move between coastal and open ocean waters. Many use estuaries as nursery areas for their young.

Coastal Birds

Birds are highly visible members of coastal ecosystems. They've evolved different feeding strategies to exploit various food sources.

Feeding Adaptations:

Oystercatchers: Strong beaks for opening shellfish
Curlews: Long curved beaks for probing mud for worms
Gannets: Streamlined bodies for diving into water to catch fish
Turnstones: Short beaks for flipping stones to find hidden prey

Adaptations to Coastal Conditions

Living in coastal environments presents unique challenges. Organisms must cope with changing tides, salt spray, wave action and varying temperatures.

Physical Adaptations

Coastal organisms have evolved remarkable physical features to survive harsh conditions.

🐞 Wave Resistance

Streamlined shapes, flexible bodies and strong attachment structures help organisms withstand wave action.

💧 Salt Tolerance

Special glands to excrete salt, waxy coatings to reduce water loss and modified kidneys to handle high salt levels.

🌡 Desiccation Prevention

Shells that seal tightly, mucus production and behavioural adaptations to avoid drying out at low tide.

Behavioural Adaptations

Many coastal organisms have developed specific behaviours to survive tidal cycles and seasonal changes.

Examples include:

Tidal migration: Fish moving with tides to access feeding areas
Burrowing: Clams and worms hiding in sediment during low tide
Seasonal migration: Birds travelling thousands of miles to exploit coastal resources
Schooling: Fish grouping together for protection from predators

Food Webs and Energy Flow

Coastal ecosystems have complex food webs with energy flowing from primary producers through multiple levels of consumers. Understanding these relationships helps explain ecosystem stability and productivity.

🌱 Energy Input

Sunlight drives photosynthesis in marine plants and algae. Nutrients from rivers and upwelling also support primary production.

⁋ Energy Transfer

Only about 10% of energy passes from one trophic level to the next. This limits the number of levels in food chains.

Case Study Focus: Morecambe Bay Food Web

Morecambe Bay's mudflats support millions of invertebrates including cockles, ragworms and shrimp. These feed over 300,000 wintering birds. The bay's primary producers include saltmarsh plants, seaweeds and phytoplankton. Predatory fish like bass and flounder feed on smaller fish and invertebrates. This complex food web supports both wildlife and commercial fisheries, demonstrating the economic importance of coastal biodiversity.

Human Impacts on Coastal Biotic Characteristics

Human activities significantly affect coastal ecosystems and their biotic characteristics. Understanding these impacts is crucial for conservation and sustainable management.

Pollution Effects

Various forms of pollution threaten coastal organisms and disrupt ecosystem functioning.

Major pollution types:

Plastic pollution: Entanglement and ingestion by marine animals
Chemical runoff: Pesticides and fertilisers causing algal blooms
Oil spills: Coating organisms and destroying habitats
Sewage discharge: Reducing oxygen levels and spreading disease

Habitat Destruction

Coastal development and human activities can destroy or degrade important habitats.

🏢 Development Pressure

Building on coastal areas destroys dunes, saltmarshes and other critical habitats. This reduces biodiversity and ecosystem services.

🚢 Fishing Impact

Overfishing removes key species from food webs. Bottom trawling destroys seafloor habitats and the organisms living there.

Conservation and Management

Protecting coastal biotic characteristics requires understanding ecosystem relationships and implementing effective conservation strategies.

Protection Strategies

Various approaches help conserve coastal biodiversity and maintain ecosystem health.

Key strategies include:

Marine Protected Areas: Restricting fishing and development in critical areas
Habitat restoration: Replanting saltmarshes and creating artificial reefs
Pollution control: Reducing inputs of harmful substances
Sustainable fishing: Setting quotas and using selective gear

Success Story: Flamborough Head

Flamborough Head in Yorkshire is a Special Protection Area supporting over 200,000 seabirds including gannets, puffins and razorbills. Protection measures have helped maintain stable populations despite human pressures. The area's chalk cliffs provide nesting sites, while surrounding waters supply abundant fish. This demonstrates how effective protection can maintain coastal biodiversity.

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