Keywords

Karenia brevis, harmful algal blooms, qPCR, light microscopy, Florida, red tide

Abstract

Harmful Algal Blooms (HABs), known as red tides, have long impacted Florida’s coastal ecosystems. Caused by the toxic dinoflagellate Karenia brevis, these blooms are named based on the characteristic red discoloration of coastal waters. Negative impacts of K. brevis range from fish kills, neurotoxic shellfish poisoning, and respiratory irritation in humans. Traditionally, K. brevis monitoring has been conducted weekly by Florida Fish and Wildlife Conservation Commission’s Fish and Wildlife Research Institute (FWC-FWRI) using light microscopy for cell identification and enumeration of collected water samples. However, this method is time-consuming, costly, and relies on deep taxonomic expertise for proper cell identification. My aim is to test an existing quantitative Polymerase Chain Reaction (qPCR) protocol for the rapid identification and quantification of K. brevis cells that is essential in HABs monitoring and mitigation programs. Water samples were collected monthly from Anna Maria Island, Palma Sola, and Clearwater Pier, areas on the Gulf Coast of Florida that are historically known to be affected by K. brevis blooms. Collections were conducted over a year to cover different stages of possible bloom events. Water samples were filtered, DNA was extracted, and qPCR experiment runs were conducted. Synthetic DNA (g-blocks) with known DNA copy numbers were run to compute relative abundance of K. brevis concentrations from the samples. K. brevis microscopy cell counts provided by FWC-FWRI showed a spike in K. brevis cell counts in November 2024 (20,000 cells/L) that diminished in subsequent months, with a smaller increase observed in December at Palma Sola (5000 cells/L). However, qPCR detected lower K. brevis concentrations across all sampling sites which were undetected by microscopy. Comparative analysis with traditional light microscopy shows that qPCR offers superior sensitivity and quantification of K. brevis blooms.

Thesis Completion Year

2025

Thesis Completion Semester

Fall

Thesis Chair

Gaither, Michelle R.

College

College of Sciences

Department

Biology

Thesis Discipline

Biology

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

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Rights Statement

In Copyright