Epiphytes of Seagrasses

Borowitzka, Michael A.; Lavery, Paul S.

doi:10.1007/1-4020-2983-7_19

Cited by 90 publications

(180 citation statements)

References 0 publications

Supporting

Mentioning

164

Contrasting

Unclassified

Order By: Relevance

“…Bacterial consumption of C was probably enhanced (Danovaro et al 2003), accelerating C cycling (López et al 1995(López et al , 1998. Epiphytes, which are known to contribute sig- nificantly to seagrass ecosystem production (Borowitzka et al 2006, Ouisse et al 2010, were not related to either C production or consumption (Apostolaki et al 2011). In contrast, NCP decreased with decreasing shoot density (annual mean 145 and 312 shoot m −2 at cages and control station, respectively; ob tained from Apostolaki et al 2009) close to the fish cages (linear regression, intercept = −1.22, slope = 0.10, R 2 = 0.52, p < 0.01), indicating declining metabolic activity of the seagrass ecosystem upon sediment nutrient enrichment.…”

Section: Discussionmentioning

confidence: 99%

Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

Apostolaki¹,

Holmer

Marbà³

et al. 2011

Aquacult. Environ. Interact.

View full text Add to dashboard Cite

We studied the relationship between sediment nutrient enrichment and carbon sequestration, using the ratio of gross primary production to respiration (P/R), in a fishfarming impacted and an unaffected Mediterranean seagrass (Posidonia oceanica) ecosystem in the Aegean Sea, Greece. Carbon (C), nitrogen (N) and phosphorus (P) sedimentation, nutrient pools in sediment and dissolved nutrients in pore water were significantly and positively intercorrelated, indicating close linkage between sedimentation and sediment nutrient pools in seagrass meadows. C, N and P sediment pools were significantly enhanced in the impacted meadow throughout the year, even during winter when fish farming activity was low. In the impacted sediment, the increase in C and N was higher than P, reflecting a faster remineralization and uptake of P than C and N. The ecosystem P/R ratio decreased exponentially with sediment nutrient enrichment. Threshold values are given for C, N and P sedimentation rates and sediment pools, and for N and P concentrations in pore waters, after which P/R ratio in the seagrass meadow decreases below 1, indicating a shift from autotrophy to heterotrophy with sediment nutrient enrichment. Such a regime shift indicates a loss of storage capacity of the seagrass ecosystem, jeopardizing the key role of P. oceanica as a carbon sink in the Mediterranean.

show abstract

Section: Discussionmentioning

confidence: 99%

Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

Apostolaki¹,

Holmer

Marbà³

et al. 2011

Aquacult. Environ. Interact.

View full text Add to dashboard Cite

show abstract

“…Grazing pressure and nutrient availability are considered to be major sources of variability of epiphyte biomass in seagrass meadows (Borowitzka et al, 2006). Sea urchins and herbivore fishes reduce the epiphyte load on Posidonia oceanica leaves (Alcoverro et al, 1997b;Tomas et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Inter-annual variation of shoot density and biomass, nitrogen and phosphorus content of the leaves, and epiphyte load of the seagrass <i>Posidonia oceanica</i> (L.) Delile off Mallorca, western Mediterranean

Terrados¹,

Medina-Pons²

2010

Sci. Mar.

View full text Add to dashboard Cite

SUMMARY:The epiphyte load, the ash content of the epiphytes, the leaf biomass, the nitrogen and phosphorus content of the leaves, and the density of shoots of the Mediterranean seagrass Posidonia oceanica (L.) Delile were monitored yearly from 2003 to 2008 in two shallow meadows off Mallorca (western Mediterranean) with the aim of identifying the responses of P. oceanica meadows to mid-term environmental variability. Inter-annual variability of P. oceanica meadows was significant for most of the descriptors examined: shoot biomass, epiphyte load, nitrogen and phosphorus content of the leaves, and shoot density. Shoot density increased by a factor of 2 and epiphyte load by a factor of 4 from 2003 to 2008. P. oceanica descriptors were generally not correlated with each other or with the average sea surface temperature during August. Long-term data series of descriptors of P. oceanica status are essential to improve understanding about the response of this important Mediterranean coastal ecosystem to natural and anthropogenic disturbances and to assess the effects of rapid global environmental change.Keywords: inter-annual variation, seagrass, epiphyte load, nitrogen, phosphorus, Posidonia oceanica, Western Mediterranean. RESUMEN: Variación interanual de la densidad de haces, biomasa foliar del haz, concentración de nitróge-no y fósforo en las hojas y de la carga de epífitos de la angiosperma marina Posidonia oceanica (L.) Delile en Mallorca, Mediterráneo occidental. -La carga de epífitos, el contenido en cenizas de los mismos, la biomasa foliar, el contenido en nitrógeno y fósforo de las hojas y la densidad de haces de la angiosperma marina Posidonia oceanica (L.) Delile se midieron anualmente desde 2003 a 2008 en dos praderas someras en Mallorca (Mediterráneo occidental) para identificar la respuesta de las praderas de P. oceanica a la variabilidad ambiental a medio plazo. Las praderas de P. oceanica presentan una gran variabilidad interanual pues la mayoría de los descriptores examinados (densidad de haces, biomasa foliar del haz, concentración de nitrógeno y fósforo en las hojas y carga de epífitos) cambiaron durante el periodo [2003][2004][2005][2006][2007][2008]. La densidad de haces se multiplicó por dos mientras que la carga de epífitos lo hizo por cuatro. No se encontró correlación entre la mayoría de los descriptores de P. oceanica ni tampoco con la temperatura del agua superficial del mar en agosto. La obtención de series temporales a largo plazo sobre descriptores del estado de las praderas de P. oceanica es necesaria para mejorar la comprensión de las respuestas de este importante ecosistema costero del Mediterráneo a perturbaciones naturales y antropogénicas y para evaluar los efectos del cambio global.Palabras clave: variación interanual, angiospermas marinas, epífitos, nitrógeno, fósforo, Posidonia oceanica, Mediterráneo occidental.

show abstract

“…Epiphytes are naturally occurring organisms that grow upon plants (as defined by Borowitzka & Lethbridge 1989, Borowitzka et al 2006. The ratio of epiphyte biomass to aboveground seagrass biomass (or plant surface area) is often referred to as the epiphyte load.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, an increase in epiphyte biomass re lative to a stable seagrass biomass results in an in creased epiphyte load. Epiphyte load (and com position) is the manifestation of a complex interaction of many factors, including light, temperature, nutrients, grazing pressure, hydrodynamics and propa gule supply (Borowitzka & Lethbridge 1989, Borowitzka et al 2006. Consequently, seagrass epiphytes are often temporally and spatially variable in the natural environment.…”

Section: Introductionmentioning

confidence: 99%

Nutrient exposure causes epiphytic changes and coincident declines in two temperate Australian seagrasses

Bryars¹,

Collings²,

Miller³

2011

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

We undertook a long-term (27 mo) field experiment to test if a chronic increase in water column nutrients could cause a decline in 2 temperate Australian seagrasses and if this decline could be linked to nutrient-mediated changes in epiphytes. Two seagrasses, Amphibolis antarctica and Posidonia sinuosa, were exposed to minor increases (~2 to 5×) in nutrient (N, P) concentrations utilising slow-release fertiliser over a 15 mo period at a shallow (~2 m depth), oligotrophic marine site in Gulf St Vincent, South Australia. Fertiliser had a significant detrimental effect on biomass, density, and canopy height in both seagrasses. Moreover, the seagrass biomass reductions coincided with increased epiphyte loads and changes in epiphyte composition. After a 12 mo recovery period, epiphyte loads in the fertiliser treatments had returned to levels comparable to the control, but the fertiliser-treated seagrasses had not recovered. While the precise mechanism of seagrass decline is still unclear, our results have demonstrated that (under certain circumstances) chronic, yet minor, increases in water column nutrient concentrations can cause the slow decline of Amphibolis and Posidonia spp. Furthermore, while future management decisions regarding anthropogenic nutrient discharges into seagrass ecosystems should be assessed on a case-by-case basis, our results and those of other workers investigating large-scale losses of Amphibolis and Posidonia in southern Australia indicate that extreme caution must be applied where these seagrasses occur in shallow, sheltered oligo trophic marine environments.

show abstract

Epiphytes of Seagrasses

Cited by 90 publications

References 0 publications

Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

Inter-annual variation of shoot density and biomass, nitrogen and phosphorus content of the leaves, and epiphyte load of the seagrass <i>Posidonia oceanica</i> (L.) Delile off Mallorca, western Mediterranean

Nutrient exposure causes epiphytic changes and coincident declines in two temperate Australian seagrasses

Contact Info

Product

Resources

About