2000 Progress Report: Developing an Indicator for Nutrient Supply in Tropical and Temperate Estuaries, Bays, and Coastal Waters Using the Tissue Nitrogen and Phosphorus Content of Macroalgae

EPA Grant Number: R827637
Title: Developing an Indicator for Nutrient Supply in Tropical and Temperate Estuaries, Bays, and Coastal Waters Using the Tissue Nitrogen and Phosphorus Content of Macroalgae
Investigators: Fong, Peggy
Institution: University of California - Los Angeles
EPA Project Officer: Hahn, Intaek
Project Period: August 1, 1999 through July 31, 2002
Project Period Covered by this Report: August 1, 1999 through July 31, 2000
Project Amount: $399,335
RFA: Ecological Indicators (1999) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Ecosystems

Objective:

Coastal eutrophication that results from increases in nutrient supply is a critical problem worldwide, causing major changes in marine populations and communities. The overall goal of this project is to develop an indicator that quantifies nutrient supply to tropical and temperate marine ecosystems using the tissue nitrogen (N) and phosphorus (P) content of macroalgae. In order to complement the present suite of indicators used to measure eutrophication, this indicator is targeted to be especially useful in systems where nutrients are supplied in pulses or those where nonpoint sources of nutrients such as groundwater or fluxes from the benthos are important. There are five specific objectives: (1) continue to identify and test potential species for use as indicators; (2) establish relationships between timing and magnitude of nutrient supply and accumulation of N and P in algal tissue; (3) establish quantitative relationships between environmental conditions, N and P supply, and tissue N and P; (4) develop a numerical simulation model based on experimental results that may be used as a "standard curve" for the indicator to hindcast nutrient supply in the field; and (5) field test the indicator.

Progress Summary:

Objective 1: Testing Potential Species. We have identified at least two tropical and two temperate species with the physiological characteristics needed for an indicator of nutrient supply. These characteristics include rapid nutrient uptake rates, a wide range of nutrient storage capacities, and the ability to tolerate a wide range of physical/chemical conditions. Thus, we targeted species that occur in a wide variety of habitats and are common within those habitats. We collected replicate samples of each species from a variety of stations with known gradients of nutrients, when possible. A "good" indicator was defined as a species that has low within station variability in tissue nutrients, but high among station variability corresponding to differences in nutrient supply. We collected from 18 stations in Puerto Rico in both wet and dry seasons, 15 stations along the Caribbean coast of Panama, 18 stations along the Pacific coast of Panama, 8 stations in Kaneohe Bay, Oahu, HI, and at 30 stations along the West Coast of the United States. Collections on the West Coast of the United States were both from within estuaries and from rocky intertidal habitats.

Our results demonstrate both Acanthophora spicifera and Hypnea musciformis are good candidates as indicators within tropical marine habitats. They have open branches and upright morphologies that extend into the water column to "sample" nutrients. They are able to sequester both N and P in proportion to supply. This is based on results of collections in Puerto Rico and both coasts of Panama. Data have yet to be analyzed for Honduras and Hawaii. Since A. spicifera was not found as commonly in the Pacific as in the Caribbean, it will be useful to use it in conjunction with Hypnea musciformis at all locations. For the West Coast of the United States, Ulva spp and Enteromorpha spp were identified as good candidate species. They are both common and collections demonstrate tissue N and P reflecting varying nutrient regimes. Ulva may be more useful than Enteromorpha in the Pacific Northwest as it is more common. In this region, Enteromorpha is largely restricted to freshwater seeps.

Objective 2: Accumulation of N and P in Tissue. To be a good indicator of nutrient supply, algae must have the ability to accumulate N and P in their tissues. To quantify this ability for the different species, we ran a series of identical experiments for each of the species in all study locations. Each experiment began with algae and water collected from a specific site. We conducted a 2 x 2 factorial experiment varying the among of N and P in the water and measured accumulation of N and P in tissues.

To date, experiments have been conducted in Puerto Rico, Honduras, the Eastern Tropical Pacific, Hawaii, Bodega (CA), and Friday Harbor Labs (WA). Data have been completely analyzed for Puerto Rico and Bodega (CA). From these experiments, we determined that all the target species identified in Objective 1 were able to sequester N and P in response to nutrient N and P addition. However, nutrient history of algae from different locations is very important in determining the ability to sequester and store nutrients. Algae that are kept under low nutrient conditions have a greater ability to take up nutrients during nutrient pulses. From this, we determined that the algae used in indicator experiments should be preconditioned in nutrient poor water prior to deployment.

Objective 3: Establish Quantitative Relationships Between Environmental Conditions, N and P Supply, and Tissue N and P. We have just begun to investigate the relationship between water flow and accumulation of N in the tissue of macroalgae. Field data from the collections, as well as the N vs. P experiments, suggest this is a very important factor influencing nutrient uptake and storage. Since our bioassay involves caging algae and placing them in the field to act as our nutrient sensor, quantifying the effects of changing water motion are important. We conducted a two factorial experiment where we varied water motion and water column nutrients in a flume at the Hawaii Institute of Marine Biology, Coconut Island, HI. Results suggest that, for H. musciformis, very little water motion (10 cm/sec-1) is needed to break down the nutrient-depleted boundary layers surrounding the thallus. This supports our conclusion from the collections, suggesting that the morphology of H. musciformis and A. spicifera may allow them to be a better indicator of water column nutrient concentration than other forms of algae.

We also have conducted several experiments assessing the effects of nutrient supply and salinity on Enteromorpha intestinalis tissue N and P content in southern California. Results showed that high N supply to the water column ameliorated the negative effects of reduced salinity. Thus, as long as supplies are high, E. intestinalis can be used as a nutrient indicator in hyposaline estuarine habitats.

Objective 4: Develop Simulation Model. In Objectives 1 through 3, we are beginning to accumulate the data needed to develop and parameterize the simulation model. We have an initial model for Enteromorpha spp that predicts growth from nutrient supply. We have yet to formally begin expanding that model and developing parallel models for other species. This will begin in Year 2.

Objective 5: Field Test Indicator. Clearly, Objectives 1 through 4 need to be further along for us to do a field test of the indicator. At present, we can use it to determine relative differences between sites within a region. We have done so along a known nutrient gradient in Puerto Rico, but the data have yet to be processed.

Future Activities:

We have a tremendous number of samples that are in various stages of analysis. The following is a summary of samples that we have collected, but have not yet analyzed, and our future directions for each objective.

Objective 1: Testing Potential Species. This objective is almost accomplished. We have a tremendous amount of information on different species in a variety of locations with different nutrient regimes. We have collected, but have yet to analyze, samples from Kaneohe Bay, HI; Santa Cruz Island, Channel Islands, CA; Cayos Cochinos, Honduras; and San Juan Island, Puget Sound, WA. Our future efforts in this objective are simply to process these samples and prepare manuscripts.

Objective 2: Accumulation of N and P in Tissue. All of the experiments proposed to investigate the ability of algal species to accumulate N and P have been completed. Most have yet to be completely analyzed. In addition, we have conducted these experiments with algae from Kaneohe Bay, HI; Santa Cruz Island, Channel Islands, CA; Cayos Cochinos, Honduras; and San Juan Island, Puget Sound, WA. Our future directions are to process samples and analyze data.

Objective 3: Establish Quantitative Relationships Between Environmental Conditions, N and P Supply, and Tissue N and P. Clearly, we are just beginning to investigate this objective of the research. We have tested the effect of water motion on one species in one location and the effects of reduced salinity on another. These experiments need to be repeated on other species of algae in different regions. In addition, we need to initiate experiments testing effects of temperature and light.

Objectives 4 and 5: Develop Simulation Model and Test Bioassay. These two objectives rely on accomplishing the first three objectives. According to our schedule, they will be initiated in Year 2.


Journal Articles on this Report : 8 Displayed | Download in RIS Format

Other project views: All 50 publications 24 publications in selected types All 22 journal articles
Type Citation Project Document Sources
Journal Article Armitage AR, Fong P. Gastropod colonization of a created coastal wetland: potential influences of habitat suitability and dispersal ability. Restoration Ecology 2004;12(3):391-400. R827637 (2000)
R827637 (2001)
R827637 (2002)
R827637 (Final)
  • Full-text: EPA-Full Text PDF
  • Abstract: Wiley-Abstract
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  • Other: ResearchGate - Abstract & Full Text PDF
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  • Journal Article Cohen RA, Fong P. Nitrogen uptake and assimilation in Enteromorpha intestinalis (L.) Link (Chlorophyta): using 15N to determine preference during simultaneous pulses of nitrate and ammonium. Journal of Experimental Marine Biology and Ecology 2004;309(1):67-77. R827637 (2000)
    R827637 (2001)
    R827637 (2002)
    R827637 (Final)
  • Full-text: ScienceDirect - Full Text HTML
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  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect - Full Text PDF
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  • Journal Article Fong P, Zedler JB. Sources, sinks, and fluxes of nutrients (N + P) in a small highly modified urban estuary in southern California. Urban Ecosystems 2000;4(2):125-144. R827637 (2000)
    R827637 (Final)
  • Abstract: Springer-Abstract
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  • Journal Article Fong P, Kamer K, Boyer KE, Boyle KA. Nutrient content of macroalgae with differing morphologies may indicate sources of nutrients for tropical marine systems. Marine Ecology Progress Series 2001;220:137-152. R827637 (2000)
    R827637 (2002)
    R827637 (Final)
  • Full-text: MEPS-Full Text PDF
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  • Abstract: MEPS-Abstract
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  • Other: ResearchGate - Full Text PDF
    Exit
  • Journal Article Kamer K, Fong P. A fluctuating salinity regime mitigates the negative effects of reduced salinity on the estuarine macroalga, Enteromorpha intestinalis (L.) link. Journal of Experimental Marine Biology and Ecology 2000;254(1):53-69. R827637 (2000)
    R827637 (Final)
    R825381 (1999)
    R825381 (Final)
  • Abstract from PubMed
  • Full-text: ScienceDirect - Full Text HTML
    Exit
  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect - Full Text PDF
    Exit
  • Journal Article Kamer K, Fong P. Nitrogen enrichment ameliorates the negative effects of reduced salinity on the green macroalga Enteromorpha intestinalis. Marine Ecology Progress Series 2001;218:87-93. R827637 (2000)
    R827637 (2002)
    R827637 (Final)
  • Full-text: MEPS-Full Text PDF
    Exit
  • Abstract: MEPS-Abstract
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  • Other: ResearchGate - Full Text PDF
    Exit
  • Journal Article Kamer K, Boyle KA, Fong P. Macroalgal bloom dynamics in a highly eutrophic southern California estuary. Estuaries and Coasts 2001;24(4):623-635. R827637 (2000)
    R827637 (2002)
    R827637 (Final)
    R825381 (1999)
    R825381 (Final)
  • Abstract: Springer-Abstract
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  • Journal Article Kamer K, Fong P, Kennison RL, Schiff K. The relative importance of sediment and water column supplies of nutrients to the growth and tissue nutrient content of the green macroalga Enteromorpha intestinalis along an estuarine resource gradient. Aquatic Ecology 2004;38(1):45-56. R827637 (2000)
    R827637 (2001)
    R827637 (2002)
    R827637 (Final)
  • Abstract: Springer-Abstract
    Exit
  • Supplemental Keywords:

    stressor, effluent, ecology, marine science, measurement method., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Ecology, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Ecological Effects - Environmental Exposure & Risk, Ecology and Ecosystems, coastal ecosystem, aquatic ecosystem, environmental monitoring, hydrological stability, nutrient supply, nutrient transport, risk assessment, bays, marine ecosystem, algae, estuaries, stressors, macroalgae, tropical ecosystems, algal growth, coastal environments, Puerto Rico, effluent, ecosystem indicators, estuarine ecosystems, tropical storms, water quality, phosphorus, ecological indicators, California (CA), Florida, nitrogen

    Progress and Final Reports:

    Original Abstract
  • 2001 Progress Report
  • Final Report