BLACK MANGROVE AND SMOOTH CORDGRASS SPECIES APPLICATIONS FOR WATER QUALITY IMPROVEMENT IN AQUACULTUR

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BLACK MANGROVE AND SMOOTH CORDGRASS
SPECIESAPPLICATIONS FOR WATER QUALITY
IMPROVEMENT IN AQUACULTURE CONSTRUCTED WETLANDS
IN SOUTH TEXAS
Monica D. Staff and Kim Jones, Ph.D. South
Texas Environmental Institute Texas AM
University-Kingsville

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Overview

• Introduction and significance
• Loma Alta Shrimp Aquaculture Facility
• Black mangrove and smooth cordgrass wetland
  microcosms
• Results thus far from field studies

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Introduction

• Constructed wetlands have been demonstrated to be
  an ecologically sound alternative for wastewater
  treatment
• A new application is to treat and re-circulate
  aquaculture effluent, however development of an
  optimal design for optimization for both water
  quality improvement and habitat enhancement is
  not clearly understood
• An understanding of the individual processes
  taking place both in natural and constructed
  wetlands is significant for improving the
  performance of constructed systems

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Introduction

• Species of interest in the study of wetland
  ecosystems include those that are highly salt
  tolerant
• Avicennia germinans (black mangrove) and Spartina
  alterniflora (smooth cordgrass) are species that
  protect and enhance coastlines by bio-filtering
  organic and inorganic substances thus keeping
  these substances from reaching the water table

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Introduction

• The objective of the current research at Texas
  AM University-Kingsville is to evaluate the
  performance of native coastal wetland plants in
  constructed wetlands designed to treat high
  salinity aquaculture effluent
• Additionally, TAMUK will determine the effect of
  organic loadings, salt concentration and flow
  rate on water quality improvement for the native
  species emergent plant wetlands

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Introduction

• Small-scale black mangrove (Avicennia germinans)
  and smooth cordgrass (Spartina alterniflora)
  wetlands are being tested to assess nutrient
  removal at high salinities simulating water
  characteristics of aquaculture effluents
• The results will provide a better understanding
  of the specific biofiltration capacity of both
  species supporting the hypothesis that mangroves
  and other native species represent excellent
  wastewater biofilters providing diverse
  ecosystems and cost-efficient water treatment

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Loma Alta Aquaculture locator map
Source Texas Aquaculture Association
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Loma Alta Shrimp Aquaculture Facility

• Two major constructed wetlands including groups
  of black mangroves form the plant community at
  Phase I of a re-circulating aquaculture-wetland
  system at the Loma Alta Shrimp Aquaculture
  Facility (LASAF), located on the El Sauz Ranch
  near Raymondville,Texas

Phase I Wetland
Phase II Wetland
Shrimp Ponds
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Mangroves at LASAF
Mangroves
Phase I wetland at LASAF. Picture by Brian Dyson.
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Removal Efficiencies for Various Constituents at
LASAF
Dyson et al (2003) studied the LASAF system in
2002 and reported reductions in several water
quality parameters through the constructed
wetlands. The following table shows removal
efficiencies of Phase I at LASAF.
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Mexican Partners

• Black Mangrove wetlands are available at the
  ACUATAM and ACUACAM aquaculture facilities near
  Tampico, Mexico
• Existing wetlands will be evaluated for nutrient
  and BOD removal in year 2004

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Black mangroves (Avicennia germinans)
Plant material, April 2004
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Black mangroves (Avicennia germinans)
Current condition of the mangroves
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Black mangroves (Avicennia germinans)
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Wetland Microcosms
Microcosm setup
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Wetland Microcosms
Microcosm setup
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Wetland Microcosms
Weir Set-up
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Wetland Microcosms
Wetland Weir
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Wetland Microcosms
Plant Layout
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Wetland Microcosms
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Wetland Microcosms
Distribution Header
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Wetland Microcosms
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Results thus far

• Limited field tests at the Loma Alta Aquaculture
  facility have demonstrated significant nutrient
  removal from aquaculture discharge water using
  Texas Gulf coast native wetland species
• A major objective of the expansion of this
  research is to improve the understanding of the
  individual role that native wetland species,
  black mangrove and smooth cordgrass, play in the
  wetland nutrient removal process

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Results thus far

• The project will also help develop a better
  understanding of the significance of hydraulic
  loading rate and salt concentrations on wetland
  nutrient removal efficiencies in the application
  of this significant ecotechnology for sustainable
  aquaculture operations
• Models for constructed wetlands design will be
  tested and evaluated to facilitate the
  application of this technology to new aquaculture
  and wastewater expansions.

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Conclusions

• The importance of mangrove ecosystems as buffer
  zones and habitats for wildlife are well known
  for the ecosystem services they provide
• The native mangrove and cordgrass ecosystems are
  also apparently performing water quality
  improvement for aquaculture operations and water
  re-circulation
• If the value of these systems can be proven in
  constructed wetlands for water treatment, their
  incorporation into the aquaculture industry of
  the future can benefit both the natural ecosystem
  and food production for a sustainable global
  environment