English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Eight experimental ponds containing submersed vascular plants (predominantly Potamogeton perfoliatus and Ruppja maritirna) were subjected in duplicate to 4 levels (including controls) of fertilization from June to August 1981. Seston and phytoplankton chlorophyll a increased with fertilization, and pronounced algal blooms were evident under high dosage. Of the total seston. phytoplankton exerted the greatest influence on attenuation of photosynthetically active radiation (PAR), such that there was insufficient light for submersed vascular plant growth at the sediment surface during bloonls. An extensive epiphytic community developed on plants in all nutrient-treated ponds at densities similar to those observed in nature on senescent plants. At high nutrient treatments the accumulation of epiphytic material resulted in > 80 % attenuation of the incident radiation at the leaf surface. Biomass of submersed macrophytes decreased significantly under high and medium nutrient treatments compared to control and low treatments within 60 d following initial fertilization. Apparent production of vascular plants (based on oxygen production and I4C-bicarbonate uptake) was reduced at the higher nutrient treatments for both R. maritirna and P. perfoliatus. Most of this reduction in macrophyte photosynthesis could be explained by attenuation of PAR associated with epiphytic material. However, without PAR attenuance in the overlying water, observed levels of epiphytic growth would be insufficient to reduce light below compensation levels needed to sustain vascular plant growth. At the high fertilization rates, integrated primary production of pond communities was significantly reduced with the loss of the vascular plants, even though phytoplankton and epiphytic growth were enhanced.

Nutrient enrichment of estuarine submersed vascular plant communities. 1. Algal growth and effects on production of plants and associated communities