Complex interactions between autotrophs in shallow marine and freshwater ecosystems: implications for community responses to nutrient stress

Havens, Karl E.; Hauxwell, Jennifer; Tyler, Anna Christina; Thomas, Serge; McGlathery, Karen J.; Cebrián, Just; Valiela, Iván; Steinman, Alan D.; Hwang, Soon‐Jin

doi:10.1016/s0269-7491(00)00154-8

Cited by 127 publications

(93 citation statements)

References 62 publications

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“…Light reduction caused decreased leaf, rhizome and root elongation rates, followed by diminished production. This phenomenon has been widely recorded in previous studies, independently of the nature of the screen used (Philippart 1995, Short & Burdick 1995, Longstaff & Denninson 1999, Moore & Wetzel 2000, Havens et al 2001, Nelson & Lee 2001, Ruíz & Romero 2001, Peralta et al 2002, Brun et al 2003a. Non-structural carbohydrates were mobilized, both in above-and belowground tissues, to meet carbon demands under light limitation (Alcoverro et al 1999, Ruíz & Romero 2001, Peralta et al 2002, Brun et al 2003a, with the capacity of sucrose formation and exportation restricted in aboveground tissues, and sink strength stimulated in belowground tissues, under low light (Brun et al 2003a).…”

Section: Discussionmentioning

confidence: 69%

“…However, the data presented here show that the addition of DOC released from Ulva rigida increases net growth, as a surplus of carbon, for Z. noltii maintenance under low light conditions. In this sense, Z. marina production was unaffected under 2 cm of macroalgal canopy height after 3 mo (Havens et al 2001). More insights in the possible uptake of DOC by seagrasses come from axenic cultures of Thalassia testudinum (Durako 1988) and Ruppia maritima (Rose & Durako 1994), where the reduction in root production in an axenic enriched sucrose medium was explained as a possible nutrient sufficiency with a reduced allocation to nutrient-absorptive root tissues.…”

Section: Discussionmentioning

confidence: 98%

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Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Brun¹,

Vergara²,

Navarro³

et al. 2003

Mar. Ecol. Prog. Ser.

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The effects of macroalgae blooms on seagrasses were assessed by shading Zostera noltii Hornem. with Ulva rigida C. Agardh mats under laboratory and field conditions. In the laboratory, where there was no direct contact between U. rigida and Z. noltii, leaf, rhizome, and root elongation rates, as well as gross production, declined as a function of U. rigida layers, causing a mobilization of non-structural carbohydrates in both above-and belowground tissues to meet carbon demands. However, when shading was performed in the field, where direct contact exists between Z. noltii and U. rigida, Z. noltii responses were not proportional to the number of Ulva layers. Elongation rates and gross production were reduced by U. rigida shading, with the lowest values under 2 Ulva layers, while there were no significant differences between controls and 4 U. rigida layers. This suggests another Ulva effect occurs besides shading. To test the likely effect of dissolved organic carbon (DOC) derived from U. rigida, Z. noltii plants were cultured under light limitation with radioactive dissolved organic carbon (DO 14 C) released by U. rigida. Plants cultured under a full DO 14 C load showed a significant enhancement of growth. The DO 14 C disappeared from the culture medium during the first 4 d of culture as a linear function of external DO 14 C concentration. This was coupled to a linear increase of radioactive particulate organic carbon (PO 14 C) in aboveground tissues, while a substantial part of this PO 14 C was allocated in belowground tissues. Overall, the PO 14 C incorporated in Z. noltii plants represented ca. 20 to 25% of the DO 14 C which had disappeared. Therefore, a net transfer of DO 14 C from U. rigida to Z. noltii has been documented. Other additional possibilities, such as a light quality effect or other kind of signals (i.e. growth factors), are discussed.KEY WORDS: Eutrophication · Heterotrophic DOC uptake · Dissolved organic carbon · Seagrass · Non-structural carbohydrates · Light reduction Resale or republication not permitted without written consent of the publisher

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 98%

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Brun¹,

Vergara²,

Navarro³

et al. 2003

Mar. Ecol. Prog. Ser.

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“…Some systems have shown a phytoplankton dominated-response (Taylor et al, 1995) while others presented macroalgal dominance (Lavery and McComb, 1991;Valiela et al, 1992). Shallow coastal estuaries with low nutrient availability in the water are more likely to be dominated by benthic algae and vascular plants due to the potential of these species to sequester nutrients from the sediments (Sand-Jensen and Borum, 1991;Havens et al, 2001). On the other hand, in systems with increased nutrient loading phytoplankton and/or macroalgae will dominate over vascular plants (Sand-Jensen and Borum, 1991.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, in systems with increased nutrient loading phytoplankton and/or macroalgae will dominate over vascular plants (Sand-Jensen and Borum, 1991. Valiela et al, 1997: Havens et al, 2001.…”

Section: Discussionmentioning

confidence: 99%

The response of primary producer assemblages to mitigation measures to reduce eutrophication in a temperate estuary

Leston

Lillebø

Pardal

2008

Estuarine, Coastal and Shelf Science

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The Mondego estuary is a well-described system located on the North Atlantic Ocean, where cultural eutrophication progressed over the last decades of the 20th century. Consequently, and due to a large productivity of Ulva spp., Zostera noltii meadows were severely reduced with a concomitant decrease in environmental quality. In 1998, experimental mitigation measures were implemented, via changes in hydrology to increase circulation and diversion of nutrient-rich freshwater inflow, to reverse the process in the most affected area of the estuary e its South arm.The objective of this study was to assess the differences in response of primary producer assemblages to the implemented measures to reduce eutrophication.Results show that the mean concentrations of DIN suffered a notorious decrease due to a significant reduction in the ammonium concentration in the water column, while DIP increased significantly. Primary producer assemblages showed different responses to these changes: phytoplankton, measured as concentration of chlorophyll a, did not show any significant changes; green macroalgae, mostly Ulva spp., suffered a large reduction in biomass, whereas Gracilaria gracilis and the macrophyte Zostera noltii biomasses increased greatly. Results show that phytoplankton biomass has remained constant and suggest that the reduction in ammonium could have been responsible for the changes in the green macroalgal biomass. Light was the most likely factor in the response of seagrass whereas red macroalgal reaction seemed to be dependent on both light and ammonium.

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“…The Comprehensive Everglades Restoration Plan (CERP) aims to address the major impacts of these hydrological diversions and impoundments and to ecologically restore this wetland by, e.g., increasing clean freshwater flow into ENP (evergladesrestoration.gov). To inform such restoration efforts, various authors have been studying the effects of drying frequency on mat primary production [42,43] and on nutrient fluxes in plant and algal communities [29,31,44,45 Figure 1) and randomly assorted into 72 beakers (400 mL) that were kept in cool, dark conditions until the start of the experiment. The mats in this region are representative of the "short-hydroperiod" (6-9 months flooding duration and more than one wet-dry cycle per year) of the upstream areas of the TS/Ph and SRS drainages [25,32].…”

Section: Study Regionmentioning

confidence: 99%

Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry

Sola

Marazzi

Flores

et al. 2018

Water

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Nitrogen (N) and phosphorus (P) concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine) influence nutrient availability, but short-term effects of drying and rewetting and long-term effects of nutrient exposure on periphyton nutrient retention are uncertain. An outdoor microcosm experiment simulated short-term exposure to variation in drying-rewetting frequency on periphyton mat nutrient retention. A 13-year dataset from freshwater marshes of the Florida Everglades was examined for the effect of long-term proximity to different N and P sources on mat-forming periphyton nutrient standing stocks and stoichiometry. Field sites were selected from one drainage with shorter hydroperiod and higher connectivity to freshwater anthropogenic nutrient supplies (Taylor Slough/Panhandle, TS/Ph) and another drainage with longer hydroperiod and higher connectivity to marine nutrient supplies (Shark River Slough, SRS). Total P, but not total N, increased in periphyton mats exposed to both low and high drying-rewetting frequency with respect to the control mats in our experimental microcosm. In SRS, N:P ratios slightly decreased downstream due to marine nutrient supplies, while TS/Ph increased. Mats exposed to short-term drying-rewetting had higher nutrient retention, similar to nutrient standing stocks from long-term field data. Periphyton mat microbial communities may undergo community shifts upon drying-rewetting and chronic exposure to nutrient loads. Additional work on microbial species composition may further explain how periphyton communities interact with drying-rewetting dynamics to influence nutrient cycling and retention in wetlands.

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Complex interactions between autotrophs in shallow marine and freshwater ecosystems: implications for community responses to nutrient stress

Cited by 127 publications

References 62 publications

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

The response of primary producer assemblages to mitigation measures to reduce eutrophication in a temperate estuary

Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry

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