Marine Plants and Organisms

Study Notes

Marine Plants

Highly productive ecosystems, harboring diverse associated species, with both underwater and vegetative reproduction.
Salt marsh plants: including mangroves, which are shrubs or small trees adapted to coastal saline or brackish water.
Mangrove trees are salt-tolerant, thrive in tropical and subtropical regions, and are adapted to harsh coastal conditions.

Marine Organisms

Cnidaria and Ctenophora: possess tissues but lack organs, characterized by radial symmetry.
Sponges: most primitive animals, aggregating specialized cells without forming true tissues. They are mostly marine and sessile.
Platyhelminthes: members of Platyzoa, flatworms are predominantly marine, encompassing turbellarians, flukes, and tapeworms.
Arthropoda: most diverse animal group, including numerous marine species.
- Trilobites: extinct arthropods.
- Chelicerates: includes horseshoe crabs, sea spiders, spiders, mites, and scorpions.
- Myriapods: millipedes and centipedes (terrestrial).
- Crustaceans: the majority of marine arthropods.
- Hexapods: insects, mainly terrestrial and freshwater.
Nematoda: one of the most diverse animal groups, essential in meiofauna and parasitic species.

Marine Crustaceans

Dominate marine arthropods.
Copepods: small crustaceans, crucial members of zooplankton, influencing marine ecology and carbon cycle regulation.
Barnacles: exclusively marine, sessile suspension feeders, dispersing during their larval stages.
Decapods: include crayfish, crabs, lobsters, shrimp, and hermit crabs. Commercially significant, they are primarily scavengers, herbivores, or carnivores.

Other Marine Arthropod Groups

Chelicerata: primarily terrestrial arthropods, including arachnids (scorpions and spiders).
- Oceanic groups: horseshoe crabs and sea spiders.

Marine Molluscs

Most diverse marine group, exceeding 200,000 species.
Characterised by a foot and typically a shell.

Marine Annelids

Segmented worms, including polychaetas, found in diverse environments.
Include earthworms and leeches.

Other Marine Organisms

Bryozoa: colonial benthic organisms, very common.
Gastropods: a diverse group of marine molluscs.

Marine Zonation

Distribution of species in vertically defined bands, corresponding to optimal conditions.
- Upper intertidal: the highest zone between low and high tide.
- Middle intertidal: the middle area between tides.
- Lower intertidal: the lowest zone between tides.
- Subtidal: below the low tide mark.

Marine Soft-Bottom Intertidal

Characterized by animals living on the substrate (epifauna).
- Distinctive feature: absence of sessile animals.
- Infauna: animals that burrow in the sediment, adapting to create holes or galleries.

Coastal Estuaries

Formed by various geological processes:
- Coastal plain estuaries: formed by rising sea levels after the last ice age.
- Bar-built estuaries: formed by sediment accumulation from rivers along the coast.
- Subside estuaries: formed by land sinking.
- Fjords: formed by glacier erosion and retreat.

Estuary Salinity

Brackish: water with intermediate salinity between oceanic and freshwater.

Marine Current Movements

Driven by various factors:
- Coriolis effect: primary driver of ocean movement, responsible for storm and hurricane rotation.
- Wind circulation: another major force influencing marine currents.
- Thermocline circulation: temperature differences drive currents.
- Tidal forces: gravitational influence of the moon and sun.
- Wave action: surface disturbances generated by wind.

Estuary Salinity Features

Salt wedge: a wedge of saline water underneath a freshwater layer, caused by density differences.
- Tidal waves: contribute to salinity changes through rising and lowering actions.
Tidal bores: high-tide-induced waves forming in funnel-shaped estuaries, reaching heights up to 20 feet, creating rapid water mixing.
Negative estuaries: found in desert areas where evaporation exceeds freshwater input, resulting in elevated salinity, reaching up to 100%.

Salinity Tolerance

Euryhaline: species tolerating a broad range of salinity levels. Not needing to relocate with salinity changes but requiring physiological adaptations.
Stenohaline: species restricted to narrow salinity ranges, requiring migration to suitable zones when salinity shifts.
Brackish water: species adapted to intermediate salinity levels.

Osmosis

Movement of water across semi-permeable membranes to maintain a balanced solvent concentration.
- Osmoconformers: organisms that allow their body fluids to change with their surroundings.

Description

Explore the diversity and adaptations of marine plants and organisms in this quiz. Learn about salt marsh plants like mangroves and the unique characteristics of various marine organisms from sponges to arthropods. Test your knowledge of these vital components of marine ecosystems!