Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 microg L(-1) above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.

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Fluctuating water levels, which characterize freshwater marshes of the Florida Everglades, U.S.A., constrain growth in emergent macrophytes. We studied acclimation of Eleocharis cellulosa Torr. (Cyperaceae) in mesocosms to water depths of 7 and 54 cm and to switching between these water depths. After 80 weeks at fixed depths, deepwater plants produced (i) taller, thicker, and fewer shoots; (ii) fewer ramets; (iii) less biomass; and (iv) greater shoot biomass relative to root and rhizome biomass. Despite large differences in shoot lengths between water depths, shoot heights above the water surface were similar. Emergent shoot tissues had thick secondary walls in the epidermal cells and several palisade layers beneath; submerged shoots lacked this anatomy. When shallow-water plants were transferred to deep water, shoots elongated rapidly, with younger shoots elongating more than older ones. When deepwater plants were transferred to shallow water, emergent shoots quickly died and were replaced by new shoots. Overall, plants exposed to rapid changes in water level adjusted biomass allocation patterns after 9 weeks towards those of control plants in their new environment, but deepwater plants responded more slowly than shallow-water plants. These shifts may allow E. cellulosa to produce shoots that optimize biomechanical support and aeration.Key words: biomass allocation, Eleocharis cellulosa, Everglades, gas exchange, shoot demography, wetland plants.

Palliative care services are underused in ILD and a supportive care decision aid can prompt consideration of palliative and supportive care needs.

2009-012671-98 (https://www.clinicaltrialsregister.eu).