Lateral Lines: Macroalgae vs. Mangrove Growth and Nutrient Uptake

Hypothesis: Given the fibrous texture, large root system, and solid
structural plant tissues of mangrove plants; they should contain and
remove more nutrients than macroalgae species in the home aquarium.

Introduction

Currently reverse daylight photosynthesis and refugia are quite
poplar. It is common practice to install and utilize the nutrient
uptake properties of macroalgae in these setups. More recently a push
towards the addition of mangroves has come to fruition. Mangroves are
considered to be excellent for nutrient uptake. In addition they have
other beneficial aspects of macroalgae including: stability (do not
dissolve during reproduction), lack of toxic chemicals, require less
space to grow, provide physical structure for other organisms, and
remove rather than recycle nutrients. Macroalgae also have a list of
benefits over mangroves including: provide a matrix for micro
crustaceans, recycle nutrients, aesthetic appeal, ease of harvesting,
and quick growth rates.

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Purpose

The purpose of this study was two fold. First the investigators
wanted to compare the dry weight (representing Nitrogen and Phosphorus
uptake) of mangroves and macroalgae. Second, the project was designed
to make in-exact measurements of nutrients, with an emphasis on useful
comparisons and terminology for home hobbyists.

Background

Several studies have focused on the limits of algal growth in reef
systems based upon Nitrogen and Phosphorus uptake (Rosenberg and Ramus
1981, Rosenberg and Ramus 1982, Lapointe et al. 1987, Littler et al.
1991, Lapointe et al. 1992, Smith & Buddemeier 1992, Fong et al.
1994,). A very noteworthy and important study in this field analyzed
the ratio of Nitrogen and Phosphorus in algal tissue (Larned 1998).
These studies are the basis for several projects which followed, and
were conducted by this project’s author (Blundell 2003). Previous
studies in the captive systems and on reef systems have been difficult
to follow or of little use to home aquarists. On main reason for this
is that studies often use measurements of grams/day or grams/linear
inch or dry weight/square meter which are too difficult to apply to
home aquariums. This project was the author’s attempt to fix this
conundrum.

Procedure

The investigators asked for algal donations and mangrove donations
from a local hobbyists club. Donors were then instructed to provide
exactly one handful of algae. While this may sound scientifically poor,
it appears to be a very universal term. Therefore actual data figures
are estimates, but generalizations can certainly be made.

Algae samples (one handful) and mangrove plants were received. All
samples were simply blotted dry and then weighted. This measurement is
a control step, and is not used in the final analysis. Then all samples
were placed in pre-weighed aluminum foil pouches. Note- mangrove
samples were first cut into parts dividing them as stems, roots, and
leaves. The aluminum foil pouches were then cooked at 350 F for six
hours.

After this time the pouches were allowed to cool and were then
weighed again. This allowed for a calculated measurement of dry mass.
The contents of each pouch were then removed and weighed separate from
the foil pounces (which were also weighted again as controls). The
calculated weights were compared with actual weights of samples, and
were identical within 1 grain.

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Table and Figures

 

SpecimenSizeDry weight in grams
Chaetomorpha sp.One Handful5.70
Caulerpa serrulataOne Handful2.59
Mangrove LeafOne Large Leaf0.19
MangroveStem (43cm/17in)8.75
Roots0.97
Leaves0.58
Total Plant10.30

Algae1.JPG
Algae5sump.JPG
Algae6stems.JPG
Algae7leaves.JPG
Algae8scale.JPG
Algae9dryitems.JPG
Algae10handful.JPG
Algae11weight.JPG

Algae2.JPG
Algae3leaves.JPG
Algae4roots.JPG

 

 

Conclusion

In this study we have found that one handful of Chaetomorpha sp. and
Caulerpa serrulata contain 5.7 grams and 2.59 grams of dry weight mass
respectively. On mangrove plant (of a length of 43cm/17in with six
leaves) weighed 10.3 grams of dry weight. If a home aquarist were able
to grow one handful of macroalgae in their sump each month, this would
equal 34.2 grams (for Chaetomorpha sp.) and 15.54 grams (Caulerpa
serrulata). This would correlate to growing 3 entire mangrove plants
and 1.5 mangrove plants during that time in that aquarium!!! That kind
of algal growth is common, but that kind of mangrove growth is
unprecedented. Therefore our hypothesis was wrong and disproved in this
study. The author’s viewpoint following this study is that mangrove
plants may be useful to aquariums but in terms of nutrient uptake they
are far inferior to macroalgae growth.

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Acknowledgments

The author would like to thank Adam Haycock, Aime Hancey, and Jake
Pehrson for donating the mangroves and algae for this project.
Appreciation is also owed to Gail Blundell for donating the measurement
equipment. A special word of gratitude is also owed to the author’s
wife who tolerated the “wonderful smell” generated from cooking algae
in a kitchen oven.

Authors Information

Adam Blundell M.S. works in Marine Ecology, and in Pathology for the
University of Utah. While not in the lab he is the president of one of
the Nation’s largest hobbyist clubs, the Wasatch Marine Aquarium
Society (www.utahreefs.com). He
is also Director of The Aquatic & Terrestrial Research Team, a
group which utilizes research projects to bring together hobbyists and
scientists. His vision is to see this type of collaboration lead to
further advancements in aquarium husbandry. Adam has earned a BS in
Marine Biology and an MS in the Natural Resource and Health fields.
Adam can be found at adamblundell@hotmail.com.

References

  1. Blundell, A. (2003) Measurement of macroalgae dry weights. Reef Ramblings 2003: 1-3.
  2. Fong, P., Donohoe, R.M., Zedler, J.B. (1994) Nutrient
    concentrations in tissue of the macroalga Enteromorpha sp. as an
    indicator of nutrient history: an experimental evaluation using field
    microcosms. Mar Ecol Prog Ser 106: 273-282.
  3. Lapointe, B.E., Littler, M.M., Littler, D.S. (1987) A comparison of
    nutrient-limited productivity in macroalgae from a Caribbean barrier
    reef and from a mangrove ecosystem. Aquat Bot 28: 243-255.
  4. Lapointe, B.E., Littler, M.M., Littler, D.S. (1992) Nutrient
    availability to marine macroalgae in siliciclastic versus
    carbonate-rich coastal waters. Estuaries 15: 75-82.
  5. Larned, S.T. (1998) Nitrogen- versus phosphorus-limited growth and
    sources of nutrients for coral reef macroalgae. Marine Biology 132:
    409-421.
  6. Littler, M.M., Littler, D.S., Titlyanov, E.A. (1991) Comparisons of
    N- and P-limited productivity between high granitic islands versus low
    carbonate atolls in the Seychelles Archipelago: a test of the
    relative-dominance paradigm. Coral Reefs 10: 199-209.
  7. Rosenberg, G., Ramus, J. (1981) Ecological growth strategies in the
    seaweeds, Gracilaria folifera (Rhodophyceae) and Ulva sp.
    (Chlorophyceae): the rate and timing of growth. Botanica mar 24:
    583-589.
  8. Rosenberg, G., Ramus, J. (1982) Ecological growth strategies in the
    seaweeds, Gracilaria folifera (Rhodophyceae) and Ulva sp.
    (Chlorophyceae): soluble nitrogen and reserve carbohydrates. Mar Biol
    66: 251-259.
  9. Smith, S.V., Buddemeier, R.W. (1992) Global change and coral reef ecosystems. A Rev ecol Syst 23: 89-118.

 

 

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About

 Adam Blundell

  (44 articles)

Adam Blundell M.S. works in Marine Ecology, and in Pathology for the University of Utah. He is also Director of The Aquatic & Terrestrial Research Team, a group which utilizes research projects to bring together hobbyists and scientists. His vision is to see this type of collaboration lead to further advancements in aquarium husbandry. While not in the lab he is the former president of one of the Nation's largest hobbyist clubs, the Wasatch Marine Aquarium Society (www.utahreefs.com). Adam has earned a BS in Marine Biology and an MS in the Natural Resource and Health fields. Adam can be found at adamblundell@hotmail.com.

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