Soil Types and Coastal Ecosystems: Characteristics and Classification

1. Zonal Soils

Zonal soils are primarily influenced by climatic factors.

High Latitudes (Tundra)

Characterized by undeveloped, poor vegetation due to extreme climatic conditions. The ground is frozen (permafrost), with a thawed surface layer called mollisol.

Mid-Latitude Cold Climates

• Podzols (or Spodosols): Have well-differentiated A, B, and C horizons. They are acidic soils with organic matter from coniferous vegetation, which acidifies the soil.
• Brown Forest Soils: Exhibit differentiated A and C profiles, with a less defined B horizon. Rich in humus due to deciduous vegetation. High rainfall leads to leaching (lixiviation).
• Gray Soils (of Continental Climates): Contain a high amount of sand. They are intermediate soils between steppe and temperate forest.

Warm Climates

• Brown and Mediterranean Soils: Feature A, B, and C horizons, with the B horizon containing a significant amount of clay. Rich in organic matter due to oak and olive vegetation.
• Black Soils (Chernozems): Very rich in nutrients.
• Desert Soils: Undergo minimal development, lacking a B horizon due to low vegetation and nutrients. Salt crusts are common.
• Laterite: Soils subjected to intensive leaching, making cultivation difficult. They have a poorly developed A horizon with little humus.

2. Azonal Soils

These are juvenile soils. According to soil formation and evolution criteria:

• Lithosols: Have a poorly developed C horizon. There are two types:
  • Rankers: The parent material is siliceous, typical of high mountain areas.
  • Rendzinas: The parent material is limestone. They have a blackish (limestone) or red (iron-rich) horizon.
• Waterlogged Soils: Characterized by insufficient drainage and anaerobic conditions, leading to putrefaction processes.
  • Gleys: Found in areas with maximum precipitation and low temperatures. They have a high accumulation of organic matter, resulting in abundant humus.
  • Peatlands: Contain even more organic matter, primarily of plant origin.
• Halomorphic Soils: Have a high salt content. Sodium (Na) determines their structure. They have little humus and sparse vegetation. Two types exist: Solonchaks and Solonetz.

3. Coastal Zones

These are contact areas between continental surfaces and the sea. They comprise the shore and the adjacent mesolittoral region (the area between high and low tide). There is no established range, as two factors modify it: the type of tide and the enhancement of marine movements that originate from the coast (currents, waves, and tides).

• Wave Flows: Caused by the ebb and flow of waves, leading to erosion, transport, and sedimentation. Waves are often diverted by winds.
• Tides: Associated with periodic currents and changes in sea level due to the displacement of large air masses.

Coastal Biology

Coastal zones exhibit high biodiversity, being among the richest geographic areas. They are dependent on three well-differentiated zones:

• Benthos: Organisms that develop on the seabed, whether sessile or mobile (e.g., crabs).
• Plankton: Organisms suspended in the water. Divided into zooplankton and phytoplankton.
• Nekton: Active swimming organisms (e.g., fish and seals).

Two types of birds are associated with the sea:

• Charadriiformes: Birds linked to beaches, meadows, and areas with water (e.g., gulls, terns, and puffins).
• Sphenisciformes: Flightless birds found on the coasts (penguins).

Trophic Characteristics

Producers in this environment are photosynthetic bacteria and phytoplankton. Consumers include zooplankton, and decomposers are bacteria that break down organic matter.

Types of Coasts

According to sea level criteria:

• Immersion Coasts: Found at river mouths (e.g., fjords, estuaries, rias).
• Emersion Coasts: Located directly in sedimentary areas where marine sediments are deposited (e.g., lagoons).

According to material type:

• Progress or Accumulation Coasts: Those where sediment deposits are very significant.
• Erosion or Abrasion Coasts: Usually high, rocky shores interspersed with areas of sediment accumulation.