Grazer-induced bioluminescence in Alexandrium mediterraneum but not in Alexandrium andersonii
(2024) BIOM02 20232Degree Projects in Biology
- Abstract
- Phytoplankton and zooplankton interactions are vital in regulating nutrient cycles and productivity in aquatic ecosystems. Nevertheless, zooplankton account for the majority of phytoplankton mortality in the ocean. Due to predation pressures, phytoplankton have evolved several defensive traits, many of them being inducible defenses such as toxin production, colony size alterations, swimming behavior, and last but not least bioluminescence. Previous findings show that copepodamides, chemical cues exuded from copepods have induced defenses in dinoflagellates. Hence, this study aims to investigate whether two underexplored Alexandrium species exhibit bioluminescence as a response to copepodamides. To test this hypothesis, two dose-response... (More)
- Phytoplankton and zooplankton interactions are vital in regulating nutrient cycles and productivity in aquatic ecosystems. Nevertheless, zooplankton account for the majority of phytoplankton mortality in the ocean. Due to predation pressures, phytoplankton have evolved several defensive traits, many of them being inducible defenses such as toxin production, colony size alterations, swimming behavior, and last but not least bioluminescence. Previous findings show that copepodamides, chemical cues exuded from copepods have induced defenses in dinoflagellates. Hence, this study aims to investigate whether two underexplored Alexandrium species exhibit bioluminescence as a response to copepodamides. To test this hypothesis, two dose-response experiments were performed using natural concentrations of copepodamides on cultures of Alexandrium mediterraneum and Alexandrium andersonii. After measuring the luminescence capacity cell counts were taken and tested whether there is any discernible cost associated with luminescence emissions. As expected A. mediterraneum showed grazer-induced bioluminescence capacity while A. andersonii did not produce measurable bioluminescence. Moreover, increased bioluminescence in A. mediterraneum’s was accompanied by a reduced growth rate, consistent with a cost associated with increased bioluminescent capacity. Additionally, A. andersonii even though not bioluminescent, at lower light intensities showed significant growth over the days. These findings not only expand our knowledge of bioluminescence as an inducible response but also indicate that trade-offs might play an important role in community composition. However, significant gaps in knowledge exist for both species. Further exploration is needed to understand all the mechanisms behind A. mediterraneum’s bioluminescence, A. andersonii’s capability of producing toxins, and the costs of such inducible defenses. (Less)
- Popular Abstract
- Illuminating Defenses in the Ocean: How Phytoplankton Fight Back?
Phytoplankton and zooplankton interactions are crucial for maintaining nutrient cycles and productivity in aquatic ecosystems. Zooplankton are a major factor in phytoplankton mortality in the oceans. As a response phytoplankton have developed fascinating defense strategies like producing toxins, altering their morphology, and even emitting luminescence.
This study explores whether two lesser-known species of the phytoplankton genus Alexandrium – Alexandrium mediterraneum and Alexandrium andersonii, can glow as a defense mechanism when exposed to chemical signals released by their predators, copepods. These chemical signals calledcopepodamides are known to trigger... (More) - Illuminating Defenses in the Ocean: How Phytoplankton Fight Back?
Phytoplankton and zooplankton interactions are crucial for maintaining nutrient cycles and productivity in aquatic ecosystems. Zooplankton are a major factor in phytoplankton mortality in the oceans. As a response phytoplankton have developed fascinating defense strategies like producing toxins, altering their morphology, and even emitting luminescence.
This study explores whether two lesser-known species of the phytoplankton genus Alexandrium – Alexandrium mediterraneum and Alexandrium andersonii, can glow as a defense mechanism when exposed to chemical signals released by their predators, copepods. These chemical signals calledcopepodamides are known to trigger defenses in other dinoflagellates, whereby two of them responded by producing bioluminescence.
To investigate this phenomenon, I conducted two experiments where I exposed cultures of A. mediterraneum and A. andersonii to natural concentrations of copepodamides. I then measured bioluminescence and growth rates, to determine if this inducible defense mechanism comes with a cost.
Results & Discussion
The results were illuminating. A. mediterraneum displayed a significant increase in bioluminescence in response to predator cues, but this came with a trade-off: their growth rate decreased. On the other hand, A. andersonii did not show any measurable bioluminescence. However, it did grow even though it was exposed to the copepodamides.
These findings enhance our knowledge of bioluminescence as a defensive response against predation in a species such as A. mediterraneum, and the associated cost leads to even more questions on how the reduced growth rate might impact community composition. Furthermore, there is much to learn about both A. mediterraneum’s bioluminescence production mechanisms, A. andersonii’s capacity to produce toxins, and the overall costs of these intriguing defense strategies.
Master’s Degree Project in Biology 30 credits 2024
Department of Biology, Lund University
Advisor: Erik Selander
Functional Ecology Division (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9154889
- author
- Zhjeqi, Andrra
- supervisor
- organization
- course
- BIOM02 20232
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9154889
- date added to LUP
- 2024-05-28 13:52:28
- date last changed
- 2024-05-28 13:52:28
@misc{9154889,
abstract = {{Phytoplankton and zooplankton interactions are vital in regulating nutrient cycles and productivity in aquatic ecosystems. Nevertheless, zooplankton account for the majority of phytoplankton mortality in the ocean. Due to predation pressures, phytoplankton have evolved several defensive traits, many of them being inducible defenses such as toxin production, colony size alterations, swimming behavior, and last but not least bioluminescence. Previous findings show that copepodamides, chemical cues exuded from copepods have induced defenses in dinoflagellates. Hence, this study aims to investigate whether two underexplored Alexandrium species exhibit bioluminescence as a response to copepodamides. To test this hypothesis, two dose-response experiments were performed using natural concentrations of copepodamides on cultures of Alexandrium mediterraneum and Alexandrium andersonii. After measuring the luminescence capacity cell counts were taken and tested whether there is any discernible cost associated with luminescence emissions. As expected A. mediterraneum showed grazer-induced bioluminescence capacity while A. andersonii did not produce measurable bioluminescence. Moreover, increased bioluminescence in A. mediterraneum’s was accompanied by a reduced growth rate, consistent with a cost associated with increased bioluminescent capacity. Additionally, A. andersonii even though not bioluminescent, at lower light intensities showed significant growth over the days. These findings not only expand our knowledge of bioluminescence as an inducible response but also indicate that trade-offs might play an important role in community composition. However, significant gaps in knowledge exist for both species. Further exploration is needed to understand all the mechanisms behind A. mediterraneum’s bioluminescence, A. andersonii’s capability of producing toxins, and the costs of such inducible defenses.}},
author = {{Zhjeqi, Andrra}},
language = {{eng}},
note = {{Student Paper}},
title = {{Grazer-induced bioluminescence in Alexandrium mediterraneum but not in Alexandrium andersonii}},
year = {{2024}},
}