Variable responses within epiphytic and benthic microalgal communities to nutrient enrichment |
| |
Authors: | Anna R Armitage Thomas A Frankovich James W Fourqurean |
| |
Institution: | (1) Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida 33199, USA |
| |
Abstract: | We evaluated how changes in nutrient supply altered the composition of epiphytic and benthic microalgal communities in a Thalassia testudinum (turtle grass) bed in Florida Bay. We established study plots at four sites in the bay and added nitrogen (N) and phosphorus
(P) to the sediments in a factorial design. After 18, 24, and 30 months of fertilization we measured the pigment concentrations
in the epiphytic and benthic microalgal assemblages using high performance liquid chromatography. Overall, the epiphytic assemblage
was P-limited in the eastern portion of the bay, but each phototrophic group displayed unique spatial and temporal responses
to N and P addition. Epiphytic chlorophyll a, an indicator of total microalgal load, and epiphytic fucoxanthin, an indicator of diatoms, increased in response to P addition
at one eastern bay site, decreased at another eastern bay site, and were not affected by P or N addition at two western bay
sites. Epiphytic zeaxanthin, an indicator of the cyanobacterial/coralline red algae complex, and epiphytic chlorophyll b, an indicator of green algae, generally increased in response to P addition at both eastern bay sites but did not respond
to P or N addition in the western bay. Benthic chlorophyll a, chlorophyll b, fucoxanthin, and zeaxanthin showed complex responses to N and P addition in the eastern bay, suggesting that the benthic
assemblage is limited by both N and P. Benthic assemblages in the western bay were variable over time and displayed few responses
to N or P addition. The contrasting nutrient limitation patterns between the epiphytic and benthic communities in the eastern
bay suggest that altering nutrient input to the bay, as might occur during Everglades restoration, can shift microalgal community
structure, which may subsequently alter food web support for upper trophic levels. |
| |
Keywords: | chemotaxonomy HPLC Florida Bay microphytobenthos seagrass subtropical estuaries |
本文献已被 SpringerLink 等数据库收录! |
|