The Ecological Role of Rhizophytic Green Algae in Soft-bottom Habitats

144 Pages·2015·1.69 MB·English

UUnniivveerrssiittyy ooff SSoouutthh FFlloorriiddaa
DDiiggiittaall CCoommmmoonnss @@ UUnniivveerrssiittyy ooff
SSoouutthh FFlloorriiddaa
USF Tampa Graduate Theses and Dissertations USF Graduate Theses and Dissertations
5-3-2012
TThhee EEccoollooggiiccaall RRoollee ooff RRhhiizzoopphhyyttiicc GGrreeeenn AAllggaaee iinn SSoofftt--bboottttoomm
HHaabbiittaattss
Laura Bedinger
University of South Florida, [email protected]
Follow this and additional works at: https://digitalcommons.usf.edu/etd
Part of the American Studies Commons, and the Ecology and Evolutionary Biology Commons
SScchhoollaarr CCoommmmoonnss CCiittaattiioonn
Bedinger, Laura, "The Ecological Role of Rhizophytic Green Algae in Soft-bottom Habitats" (2012). USF
Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/3972
This Dissertation is brought to you for free and open access by the USF Graduate Theses and Dissertations at
Digital Commons @ University of South Florida. It has been accepted for inclusion in USF Tampa Graduate Theses
and Dissertations by an authorized administrator of Digital Commons @ University of South Florida. For more
information, please contact [email protected].
The Ecological Role of Rhizophytic Green Algae in Soft-bottom Habitats

by

Laura Ann Bedinger

A dissertation submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
Department of Integrative Biology
College of Arts and Sciences
University of South Florida

Major Professor: Susan S. Bell, Ph.D.
Clinton J. Dawes, Ph.D.
Peter D. Stiling, Ph.D.
Kevin S. Beach, Ph.D.

Date of Approval:
May 3, 2012

Keywords: Bryopsidales, rhizoid, Florida, seagrass bed, biomass, succession,
disturbance, vegetative reproduction, regeneration, secondary metabolite, fouling

Copyright © 2012, Laura Ann Bedinger
DEDICATION

This dissertation is dedicated to my amazing husband Matt and my loving parents
Gail and Mike. Without their continued support and encouragement this dissertation
would not have been possible. It is also dedicated to the ocean and the algae for being a
source of inspiration.
ACKNOWLEDGMENTS

I would like to express my gratitude to my major professor, Susan Bell, for the
guidance and support she has provided throughout my doctoral degree and for helping me
expand my knowledge of marine ecology. Clinton Dawes graciously shared his
knowledge of marine botany, provided helpful feedback on my work, introduced me to
scanning electron microscopy, and was very helpful throughout my degree, for all of
which I am grateful. Valerie Paul was a great summer fellowship mentor and I
thoroughly enjoyed my summer at SMS, Fort Pierce where I learned a lot. Thanks go to
Peter Stiling and Kevin Beach for serving on my committee and their input into my
research and manuscripts.
Financial support was provided by a Link Foundation/Smithsonian Institution
Fellowship, a Tharp Summer Fellowship from USF Biology, a Summer Pre-doctoral
Fellowship from USF Graduate School, Fern Garden Club, Orange Blossom Garden
Club, and Sigma Xi.
Thanks go to many graduate students and post docs for their help and friendship
as I pursued this doctorate including: Jenny Peterson, Mike Middlebrooks, Justin Krebs,
Kerry Bohl, Theresa Meickle, Katie Basiotis, Amy Erickson, Lesley Porter Baggett,
Louise Firth, Stacy Villanueva, Alison Meyers, and Michael Meads. Many people at USF
deserve thanks for contributing in a variety of ways to my research or other aspects my
graduate student career. These people include: Christine Brubaker, Mary Parrish, Betty
Loraamm, Skip Pierce, Frederick Essig, Jim Garey, Jason Rohr, and John Lawrence.
Many undergraduates helped me complete this research both in the field and in the lab.
Sam Shiver, Jennifer Strykowski, and Natalie McCune all contributed many, many hours,
braving cold, heat, and thunderstorms in the field and tedium in the lab. I would like to
thank Holly Gray for drawing the first figure in Chapter Three. And lastly, but most
importantly, I thank Matt Neilson for his tremendous support and fantastic home-cooked
meals.
TABLE OF CONTENTS

List of Tables ............................................................................................................... iii

List of Figures ................................................................................................................ v

Abstract ........................................................................................................................vii

Chapter One: A Synoptic Review of the Ecology of Rhizophytic Green Algae ................ 1
Rhizophytic Algae and Rhizoids .......................................................................... 1
The Importance of Rhizophytic Algae .................................................................. 3
Rhizophytic Algae, Succession, and Interaction with Seagrasses .......................... 4
Other Community Level Interactions ................................................................... 6
Organization of This Dissertation ....................................................................... 10
Literature Cited .................................................................................................. 11

Chapter Two: Rhizophytic Algal Communities of Shallow, Coastal Habitats in
Florida: Components Above and Below the Sediment Surface ....................... 16
Introduction ....................................................................................................... 16
Methods ............................................................................................................. 19
Data analysis .......................................................................................... 23
Results .............................................................................................................. 25
Plant community composition ................................................................ 25
Aboveground thalli ................................................................................. 27
Sediments ............................................................................................... 28
Holdfasts ................................................................................................ 29
Above- and belowground comparisons ................................................... 33
Discussion ......................................................................................................... 35
Plant community composition ................................................................ 35
Above- and belowground components .................................................... 38
Ecological implications .......................................................................... 42
Conclusions ............................................................................................ 43
Literature Cited .................................................................................................. 44

Chapter Three: Regeneration and Recolonization of Rhizophytic Green Algae
(Bryopsidales, Chlorophyta) by Vegetative Reproduction in Field
Experiments ........................................................................................... 64
Introduction ....................................................................................................... 64
Methods ............................................................................................................. 70
Overview of study design and locations .................................................. 70
Regeneration from manipulated holdfasts ............................................... 71
i
Holdfast size and regeneration ................................................................ 72
Recruitment of new plants ...................................................................... 73
Results ............................................................................................................... 75
Regeneration from manipulated holdfasts ............................................... 75
Holdfast size, regeneration, and handling control .................................... 76
Recruitment of new plants ...................................................................... 78
Discussion.......................................................................................................... 82
Summary ................................................................................................ 89
Literature Cited .................................................................................................. 90

Chapter Four: Secondary Metabolites Are Not Used by Rhizophytic Green Algae
(Order Bryopsidales) to Inhibit Surface Fouling ................................... 112
Introduction ..................................................................................................... 112
Methods ........................................................................................................... 114
Collection and Handling of Seaweeds ................................................... 114
Surface Extractions ............................................................................... 114
Whole Plant Extractions ....................................................................... 115
Analysis of Extracts .............................................................................. 116
Surface Morphology ............................................................................. 116
Results ............................................................................................................ 117
Discussion........................................................................................................ 118
Literature Cited ................................................................................................ 120

Appendix A: Holdfast-Handling Control Experiment................................................... 128

Appendix B: Scanning Electron Micrograph of Caulerpa prolifera rhizoids ................ 130

ii
LIST OF TABLES

Table 2.1: The number of rhizophytic algal individuals sampled by date and
location (total area = 1.375 m2 at each site) and the number of quadrats
in which each species was found ................................................................. 49

Table 2.2: Mean (± SD) % cover of seagrass and number of quadrats with
seagrass present ........................................................................................... 50

Table 2.3: Results of one-way analysis of similarity (ANOSIM) pairwise tests on
abundance, ash-free dry weight (AFDW), and holdfast volume of
rhizophytic algal species at all pairs of sites ................................................. 51

Table 2.4: Organic content (percent of sample weight ± SD) of whole
aboveground rhizophytic algal thalli collected at each site ........................... 52

Table 2.5: Mean (± SD) of height (cm), holdfast depth (cm), and holdfast volume
(ml) per rhizophytic individual for all algal species present at each site ........ 53

Table 2.6: Sediment organic and carbonate composition (mean percentage of
sample dry weight ± SD, n = 3) for the four transect sampling sites in
Florida ......................................................................................................... 54

Table 2.7: Organic and carbonate content (percent of sample weight ± SD) of
rhizophytic algal holdfasts by site ................................................................. 55

Table 2.8: Pearson correlation of aboveground thallus wet weight (g) and holdfast
volume (ml) and of thallus height (cm) with holdfast depth (cm) .................. 56

Table 2.9: Aboveground biomass (g/m2 AFDW) and belowground holdfast
volume (ml/m2) data for dominant rhizophytic algal species by site .............. 57

Table 2.10: Comparison of rhizophytic algal thallus (and seagrass short shoot)
densities by plant type and location .............................................................. 58

Table 2.11: Comparison of rhizophytic algal/seagrass community dry weight by
plant type and location ................................................................................. 59

Table 2.12: Comparison of reported means of rhizophytic algal thallus height,
holdfast depth, and holdfast volume by plant type and location .................... 60

iii
Table 3.1: Summary of experiments including dates, locations, and essential
features ........................................................................................................ 96

Table 3.2: Results of regeneration experiments showing the duration (days) each
experiment ran, the number of holdfasts originally planted, the number
recovered from undisturbed plots, the percentage of undisturbed
holdfasts that regenerated new aboveground material, the mean (± SE)
dry weight of new aboveground thallus material generated per
holdfast, and the mean (± SE) height of the new material (top edge of
the manipulated stipe stub to the uppermost part) for each species ................ 97

Table 3.3: Percent change and holdfast volume (mean ± SE) of tagged individuals
from the start to the conclusion of the experiments/handling control by
species and thallus manipulation................................................................... 98

Table 3.4: Pearson correlation coefficients (r) and p values from holdfast
regeneration experiment on H. incrassata and P. capitatus at Crystal
Beach in August 2009 .................................................................................. 99

Table 3.5: The number of individual rhizophytic algal colonizers and the number
of plots colonized by species in the summer 2009 regeneration/
recolonization experiments ......................................................................... 100

Table 3.6: Mean (± SE) holdfast volume, height, and aboveground dry weight of
individual thalli for each species of colonizer from the experiments at
Sunset Beach (28-30 days) and Crystal Beach (22-24 days) in summer
2009 compared with mean values from the natural population in the
same area at Sunset Beach sampled on 29 June 2007 .................................. 101

Table 3.7: Number (mean ± SE) of new rhizophytic algal thalli m-2 that recruited
into cleared plots over 51 days (June-August 2008) at both sites in the
natural recolonization experiment and in the regeneration/
recolonization experiments in June 2009 at Sunset Beach (28-30 days)
and in August at Crystal Beach (22-24 days) .............................................. 102

Table 3.8: Braun-Blanquet scores of each species found in plot borders at Fred
Howard Park and the number of individuals that recruited into the
plots over 51 days....................................................................................... 103

Table 3.9: Braun-Blanquet scores of each species found in plot borders at Sunset
Beach and the number of individuals that recruited into the plots over
51 days ....................................................................................................... 104

Table .4.1: Presence or absence of non-polar secondary metabolites in surface and
whole tissue extracts as detected in 1HNMR spectra of four rhizophytic
green algal species...................................................................................... 123
iv
LIST OF FIGURES

Figure 2.1: Transect sampling sites in Florida: Sunset Beach (28° 08.72' N, 82°
47.51' W), Mote Tropical Research Laboratory (24° 39.62' N, 81°
27.31' W), Bahia Honda (24° 39.37’ N, 81° 16.80’ W), and Little
Duck Key (24° 40.83' N, 81° 13.78' W) ........................................................ 61

Figure 2.2: Aboveground rhizophytic algal biomass as total dry weight and ash-
free dry weight by species composition and site/sampling date ..................... 62

Figure 2.3: Rhizophytic algal holdfast volume by species composition at each
site/sampling date ......................................................................................... 63

Figure 3.1: Vegetative reproduction in the rhizophytic alga, Penicillus capitatus ......... 105

Figure 3.2A: Mean density of new aboveground thalli of each species that
recruited into a single plot (0.04 m-2) of each treatment during over the
28-30 days of the June 2009 experiment at Sunset Beach ........................... 106

Figure 3.2B: Mean density of new aboveground thalli of each species that
recruited into a single plot (0.04 m-2) of each treatment during over the
22-24 days of the August 2009 experiment at Crystal Beach ...................... 106

Figure 3.3: Mean (± SE) dry weight (g) of new aboveground thalli and holdfast
volume (ml) that recruited into experimental plots during the 28-30
days of the June 2009 experiment at Sunset Beach and the 22-24 days
of the August 2009 experiment at Crystal Beach ........................................ 107

Figure 3.4: Mean (± SD) density of new recruits per plot (0.04 m2) of each
rhizophytic algal species given Braun-Blanquet (BB) score for that
species in borders around plots in 51 day natural recolonization
experiment at Fred Howard Park 2008........................................................ 108

Figure 3.5: Mean density of new recruits per plot (0.04 m2) of each species (noted
on the x-axis) into those plots with the border Braun-Blanquet score
for that species (also given on the x-axis) ................................................... 109

Figure 3.6: Mean length of Caulerpa cupressoides stolon inside a plot (0.04 m2)
at Sunset Beach in 51 day natural recolonization experiment ...................... 110

v