Physiological models of performance for scleractinian corals Article Swipe

MAKE IMPACT

Mia O. Hoogenboom · YOU? · · 2024 · Open Access · · DOI: https://doi.org/10.25903/evq8-b235

A fundamental objective of ecology is to evaluate the conditions that permit \ndifferent species to survive and reproduce, that is, to identify each species’ ‘niche’. \nThe overarching aim of this thesis was to identify and quantify the primary processes \nthat influence the distribution and abundance of reef-building, scleractinian corals. \nMy general approach was to develop and calibrate process-based models that link \nphysiology to environmental conditions, and quantify ecological performance as a \nfunction of physiology. \n \nLight intensity is a fundamental determinant of coral performance. For \nseveral photosynthetic taxa exposure to high light levels causes a decline in daily \ncarbon gain. In this thesis I first investigated whether this phenomenon (i.e. \nphotoinhibition) had energetic consequences for coral symbioses. Surprisingly, \nresults demonstrated that costs of photoinhibition are negligible under short-term \nexposure to high irradiance (Chapter 2). I subsequently investigated whether costs of \nphotoinhibition manifest over a longer time-period due to changes in the \nphotosynthetic apparatus that arise during photoacclimation to high light intensities \n(Chapter 3). Analyses revealed that repeated exposure to high light intensity causes \nchanges in the photosynthetic machinery such that high-light habitats do not provide \nmaximal energy acquisition. In fact, I found evidence of a strong reduction in energy \navailable for growth and reproduction for corals growing under high light. \n \nCorals potentially avoid costs of excessive light exposure by altering colony \nmorphology. Previously, no framework has been available that allowed comparison \nof energy acquisition for multiple, complex coral morphologies, in response to \nvarying light conditions, while taking into account the flexibility in coral \nphotophysiology. Using a novel, three-dimensional geometric model of light capture \nin combination with a comprehensive photosynthesis dataset, in Chapter 4 I \ndemonstrate that morphological plasticity maximizes the amount of energy corals \nhave available for growth and reproduction. In addition, results showed that variation \nin morphology is most important at niche boundaries whereas physiological \nflexibility is important in intermediate habitats. \n \nIn addition to light intensity, water flow velocity varies markedly between \nreef habitats and has a strong influence on coral metabolism. In this thesis, I built on \nexisting models of gas exchange to incorporate the effects of light intensity, flow \nvelocity and colony size into a single model (Chapter 5). Analysis of this model \nshowed that the branching coral Acropora nasuta has a positive energy balance over \na wider range of conditions than both a massive (Leptoria phrygia) and a foliose \nspecies (Montipora foliosa). Moreover, colony size was revealed as having a strong \ninfluence on niche width: large colonies of all three species had a positive energy \nbalance over a broader range of conditions than small colonies. \n \nThe overarching aim of my thesis was to evaluate the performance of corals \nin response to environmental gradients. This work quantifies the mechanisms \nthrough which light and flow influence coral physiology. Model predictions were \nstrongly correlated with observed tissue biomass and reproductive output. In \naddition, an optimality model based on morphology-specific energy acquisition as a \nfunction of the ambient light-regime, adequately captured observed variation in \ncolony shape across a depth gradient. Overall, this thesis provides new insight into \nthe processes underlying the habitat distributions of reef-building corals, achieved by \nquantifying environmental effects on physiology and integrating these effects into an \nenergy-budget framework.

Type

dissertation

Language

en

OA Status

green

References

7

Related Works

20

OpenAlex ID

https://openalex.org/W135058996

Raw OpenAlex JSON

OpenAlex ID

https://openalex.org/W135058996

Canonical identifier for this work in OpenAlex

DOI

https://doi.org/10.25903/evq8-b235

Digital Object Identifier

Title

Physiological models of performance for scleractinian corals

Work title

Type

dissertation

OpenAlex work type

Language

en

Primary language

Publication year

2024

Year of publication

Publication date

2024-08-15

Full publication date if available

Authors

Mia O. Hoogenboom

List of authors in order

Open access

Yes

Whether a free full text is available

OA status

green

Open access status per OpenAlex

OA URL

https://doi.org/10.25903/evq8-b235

Direct OA link when available

Concepts

Photoinhibition, Ecology, Photosynthesis, Biology, Coral, Light intensity, Coral reef, Botany, Physics, Optics, Photosystem II

Top concepts (fields/topics) attached by OpenAlex

Cited by

0

Total citation count in OpenAlex

References (count)

7

Number of works referenced by this work

Related works (count)

20

Other works algorithmically related by OpenAlex

Full payload