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

In an experimental mesocosm system during late summer-fall, we examined shoot production by eelgrass Zostera marina without nitrate additions (generally with ambient water-column concentrations c 2 pM N03--N) versus production by eelgrass that previously had been exposed to low nitrate enrichment (pulsed additions of 5 pM NO,--N d-' to the water for 12 wk during an unusually cool spring season). During late summer-fall, the previously enriched plants were subjected to higher nitrate loading (10 pM NO<-N d-' for 14 wk), while control plants were maintained without nitrate additions as in spring. We also compared shoot production in fall by recent field transplants of Z. manna, Halodule wrightii, and Ruppia rnarit~rna with and without additions of 10 pM water-column NO3--N d' . Low water exchange (10% d-l) was used to s~mulate conditions in sheltered embayments or lagoons, and light reduct~on from high tide was simulated by covering the mesocosnls with neutraldensity screens that reduced incident light by 30 % for 3 h d.' on a rotating schedule. Shoot production by both enriched and unenriched Z. marina was comparable dunng the spring low-level NO3--N exposure. However, eelgrass enriched with nitrate in both spring and fall attained significantly lower shoot production than control plants without enrichment. This decrease, unrelated to light reduction from algal growth, suggests a direct adverse effect of long-term water-column nitrate exposure on Z. marina. The more recent transplants of eelgrass without prior enrichment history also showed a trend for decreased lateral growth under moderately elevated nitrate. In contrast, H. wrightii was slightly stimulated and R. rnaritima was highly stimulated by water-column nitrate relative to growth of controls. By the end of the fall experiment, Z. marina (f NO3--N), H. wrightii (k NO3--N), and unenriched R. maritima had increased shoot densities by <50%, whereas nitrate-enriched R. maritima increased shoot production by >300%. The data indicate that H. wrightii or R. maritima could be established successfully by transplanting efforts as a management strategy in nitrate-enriched waters where eelgrass meadows have disappeared. Unlike 2. marina, these species apparently have developed physiological mechanisms to more effectively control nitrate uptake and metabolism.

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