14_Red Tides and Marine Plankton

Introduction

• Title: Red Tides and Plankton in Florida

• Presented by: Dr. Jaclyn Miranda

• Course: ESC1000C – Earth Science

• Date: March 5, 2025

• Affiliations: FWC, NOAA

Agenda

• Sections Covered:

  • Ocean food webs

  • Marine plankton

  • Red tides

  • Red Tide and Marine Plankton Lab

Key Concepts

Ocean Structure

• Thermocline, Halocline, Pycnocline: Key layers in ocean stratification affecting nutrient distribution and marine life.

• Light Availability: Crucial for photosynthesis, varies with depth and distance from shore.

• Water Depth: Affects marine ecosystem dynamics and organism distribution.

Ocean Food Webs

• Food Chain: Direct sequence showing energy transfer through organisms.

• Food Web: Complex interconnections among multiple food chains; promotes survival.

Oceanic Feeding Relationships

• Main Producers:

  • Marine algae

  • Plants

  • Bacteria & archaea

• Energy Transfer:

  • Inefficient transfer of energy, approx. 10% of energy passes to the next trophic level.

Ocean Productivity

Factors Driving Productivity

• Primary Production: Driven by photosynthesis (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂).

• Essentials for Photosynthesis: Sunlight, CO₂, Nutrients (N, P).

• Energy Sources:

  • Photosynthesis (solar energy)

  • Chemosynthesis (chemical reactions)

Productivity by Ocean Zone

• Polar Oceans: Nutrient-rich due to upwelling; limited by low solar energy.

• Tropical Oceans: Low productivity due to thermocline barriers limiting nutrients.

• Temperate Oceans: Seasonal variations influence productivity—high in spring, low in winter.

Marine Plankton

Types of Plankton

• Phytoplankton: Photosynthetic microbes, primary producers.

• Zooplankton: Heterotrophs that consume phytoplankton; includes holoplankton (lifetime plankton) and meroplankton (larval stage).

• Bacterioplankton, Mycoplankton, Virioplankton: Other forms contributing to oceanic life.

Sampling Techniques for Plankton

• Collection Methods: Using plankton nets with varying mesh sizes (200 µm in temperate areas, 70-100 µm in tropics).

• Sample Processing: Preservation methods (formalin or Lugol’s solution) and microscopy for identification.

Red Tides

Definition and Causes

• What is a Red Tide?: Harmful algal blooms caused by Karenia brevis, resulting in neurotoxin production.

• Conditions Favoring Blooms: Optimal light, temperature, nutrient levels, and wind patterns.

Impacts of Red Tides

• On Marine Life: Toxic effects on fish, turtles, dolphins, leading to health issues and fatalities.

• On Humans: Respiratory and skin irritations, economic impacts (tourism and fisheries).

Red Tide Sampling

• Collection & Preservation: Using Niskin bottles for depth sampling and Lugol’s solution for preservation.

• Analysis: Counting and identifying phytoplankton from samples.

Review Questions

• Producers in Marine Ecosystems: Marine algae, bacteria, and archaea are primary producers.

• Energy Transfer Efficiency: Approximately 10% is transferred between trophic levels.

Conclusion

• Next Class Topics: Dynamic ocean, waves, and tides; preparation through assigned readings.