scholarly journals Comparative effects of water-column nitrate enrichment on eelgrass Zostera marina, shoalgrass Halo-dule wrightii, and widgeongrass Ruppia maritime

1994 ◽  
Vol 105 ◽  
pp. 121-138 ◽  
Author(s):  
JM Burkholder ◽  
HB Glasgow ◽  
JE Glasgow
Keyword(s):  
Water Column ◽  
Zostera Marina

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

Survival and re-establishment of vegetative fragments of eelgrass (Zostera marina)

1996 ◽  
Vol 74 (10) ◽  
pp. 1584-1590 ◽  
Author(s):  
Patrick J. Ewanchuk ◽  
Susan L. Williams
Keyword(s):  
Population Growth ◽  
Water Column ◽  
Asexual Reproduction ◽  
Aquatic Plants ◽  
Zostera Marina ◽  
San Diego ◽  
Potential Contribution ◽  
Mission Bay ◽  
Survival And Growth ◽  
Eelgrass Beds

Vegetative fragmentation of clonal aquatic plants is considered a form of asexual reproduction. Although vegetative fragmentation of eelgrass (Zostera marina L.) is considered a mode of asexual reproduction and dispersal, no data exist to evaluate the potential contribution of fragments (rhizomes with meristems and green leaf shoots) to eelgrass populations. We estimated (i) the size of the fragment population relative to the size of adjacent eelgrass populations, and (ii) the potential for fragments to re-establish in eelgrass beds in Mission Bay, San Diego, Calif. We surveyed the abundance of fragments on adjacent beaches and determined the survival and growth of detached fragments and of fragments re-established in eelgrass beds after varying time spent in the water column. Although vegetative fragments occurred throughout the year, but mostly in winter, they represented a loss of <4% of the leaf shoots in adjacent eelgrass populations. Only 60% of the fragments survived in the water column after 6 weeks, and growth and survivorship of re-established fragments declined with time spent in the water column. Thus, fragmentation represents a small net loss to the eelgrass beds studied and is not a common recruitment mechanism. This result does not support the hypothesis that asexual reproduction in the form of vegetative fragments contributes to eelgrass population growth. Because successful re-establishment is improbable, vegetative fragments also are not likely to contribute substantially to eelgrass dispersal, at least in Mission Bay. Keywords: eelgrass, asexual reproduction, clone fragmentation, Zostera marina.

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

scholarly journals Wax and wane of eelgrass Zostera marina and water column silicon levels

1996 ◽  
Vol 144 ◽  
pp. 303-307 ◽  
Author(s):  
PMJ Herman ◽  
MA Hemminga ◽  
PH Nienhuis ◽  
JM Verschuure ◽  
EGJ Wessel
Keyword(s):  
Water Column ◽  
Zostera Marina
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