life in the sea
Coral Reefs
Location and Conditions
Favorable to warm waters
Favorable to clear waters
Nutrient-poor environments are preferred because excess nutrients can lead to overgrowth of algae, which can harm coral health.
Types of Coral Reefs
Fringing Reefs
Common off Florida and the Caribbean (e.g. Ocean Reef Park, Coral Cove)
Barrier Reefs
Historically significant (e.g. Palm Beach as a former barrier reef)
Atolls
Formed from extinct volcanoes, typically circular;
Erosion and wave action lead to formation from mountains to atolls.
Historical Research Findings
1950s research using radiometric data supported the evolution theory of reef formation.
Reef Zones
Movement from beach through the lagoon to the back reef:
Beach - area where waves hit directly, gradually moving to…
Lagoon - a shallow area behind the reef… to…
Back Reef - shallower areas…
Crest - where waves break (dominant stony corals are found).
Buttress Zone - deeper and more diverse.
Notable Examples
The Maldives, Sombrero Key (Marathon Key Florida) are highlighted as rich in fish and coral diversity.
Coral Structure
Only the top layer of coral is alive; the coral consists of polyps in a colony.
Two types of corals:
Hermatypic (reef-building corals)
Ahermatypic (non-reef-building corals)
Polyps can reproduce via budding (asexual reproduction) or through gametes released in the water column (sexual reproduction).
Biodiversity & Ecosystem Importance
Coral reefs support about 25% of all marine organisms during aspects of their lifecycle (larvae, plankton, adults).
Essential for ecosystem services (tourism, ecotourism, fisheries among others).
Economic Impact
Coral reefs support Floridian economies (commercial fishing and tourism).
Examples of tourist attractions negatively affected by reef health (e.g. Saint Croix).
Physical Protection Role of Reefs against Erosion
Waves breaking on reefs prevent erosion; the sand content often includes disintegrated reef material.
Helps maintain beach integrity by dissipating wave energy offshore.
Human Interactions and Threats to Coral Reefs
Economic Dependence
Florida’s lack of state income tax is aided by ecotourism from coral reefs.
Threats to Coral Reefs
Overfishing, fishing pressure, and anchor damage to coral reefs.
Mooring Balls - a solution to prevent damage from anchors.
Destructive Fishing Techniques
Trawling - metal cages catching everything at the ocean floor;
Ghost Nets - lost nets causing unintended damage to marine life.
Dynamite Fishing and Cyanide Fishing - methods for capture affecting ecosystem health.
Pollution Impact
Plastic pollution and its effects on marine life (e.g. ingestion by fish).
Oil spills from boats causing surface pollution.
Nutrient runoff from human sewage and agriculture fostering cyanobacteria and algae blooms.
Invasive Species Impact
Definition of Invasive Species
Organisms introduced to non-native regions post-Columbian exchange (post-1492).
Exotic Species and problematic species such as Lionfish, concerning their predatory behavior and stress on native fish populations.
Lionfish Characteristics
Native to the Indo-Pacific; invasive in Atlantic waters.
Known for voracious appetite and venomous spines, potentially causing pain and swelling if handled improperly.
Population explosion observed, especially along Florida coasts, harming native fish population significantly.
Efforts to Control Invasive Species
Spearfishing and public contests to reduce populations.
Coral Reefs and Climate Change
Ocean Acidification
Increased CO₂ leads to carbonic acid formation, reducing calcium carbonate availability for coral structures.
Correlation between carbonic acid and coral health (skeletons and shells weakening).
Temperature Effects
Warmer water leading to coral bleaching, where stressed corals expel symbiotic algae (zooxanthellae) causing coral tissue loss (visible skeleton appearance).
Higher susceptibility to diseases like yellow band disease due to thermal stress.
Coral Research and Conservation Efforts
Efforts to monitor coral health and address bleaching incidents.
Observations made in the Florida Keys about the importance of temperature regulation and protection of coral ecosystems.
Different genetic strains of coral with varying tolerances to temperature rising.
Arthropods Overview
Definition and Importance
Largest phylum: over 1,000,000 species including crabs and lobsters.
Arthropod Characteristics
Segmented bodies and jointed appendages (metamerism).
Chitinous exoskeletons.
Unique molting process necessary for growth.
Horseshoe Crabs
First Group of Arthropods Discussed
Class Merostomata, commonly: Limulus Polyphemus.
Found along American continental shelf.
Anatomy and Features
Body regions: carapace, cephalothorax, abdomen, and telson.
Distinction from other arthropods: lack of antennae.
Reproductive Behavior
Dioecious; males and females show sexual dimorphism.
Spawn during spring/summer under specific tidal conditions.
Economic Significance
Horseshoe crab blood contains Limulus Amebocyte Lysate (LAL) used in medical testing costing about $60,000 a gallon.
Concerns over population decline due to harvesting for medical use and potential preservation needs.
Research Applications
Horseshoe crabs used in vision studies due to distinct eye structures, highly researched in comparison to human vision technology.
Crustaceans
Definition and Examples
Second group of arthropods including crabs, lobsters, shrimp, and copepods.
Crustacean Characteristics
Distinctive feature: two pairs of antennae.
Dioecious; reproductive methods involve copulatory and brooding behaviors.
Planktonic life stages post-hatch.
Diversity
Estimated around 40,000 species, predominantly aquatic in nature.
Industrial Importance
Key role in fisheries and marine ecology.
Learning Forward
Future discussions on specific crustacean groups planned for the next session.