Seasonal effects of clams(Panopea generosa)on eelgrass(Zostera marina)density but not recovery dynamics at an intertidal site

2012 ◽  
Vol 22 (6) ◽  
pp. 712-720 ◽  
Author(s):  
Jennifer L. Ruesink ◽  
Kirsten Rowell
Keyword(s):  
Zostera Marina ◽  
Seasonal Effects ◽  
Recovery Dynamics ◽  
Intertidal Site

Structural and functional adaptations of eelgrass (Zostera marina L.) to the anaerobic sediment environment

1983 ◽  
Vol 61 (5) ◽  
pp. 1421-1428 ◽  
Author(s):  
Polly A. Penhale ◽  
Robert G. Wetzel
Keyword(s):  
Bering Sea ◽  
Zostera Marina ◽  
Root Respiration ◽  
Laboratory Experiments ◽  
Sulfide Concentration ◽  
Gas Composition ◽  
Collective Data ◽  
Physiological Adaptations ◽  
Gas Volume ◽  
Intertidal Site

Structural and functional adaptations of the seagrass Zostera marina L. to the anaerobic sediment environment were examined both experimentally and under natural conditions along a transect including environmentally different sites in Izembek Lagoon, Bering Sea, Alaska. Aerobic root respiration rates, end products of anaerobic metabolism in roots and rhizomes, lacunal development, and internal gas volume and gas composition were compared among plants from three sites. Root respiration decreased across the transect from the intertidal site to the two subtidal stations of increased sediment anaerobiosis. Ethanol concentrations of roots and rhizomes were very low in all cases and shikimate could not be detected. Malate concentrations in the rhizome tissues were high in the midbed portion of the transect and lower at both the intertidal and deep edges of the bed; malate concentrations of root tissue followed a reciprocal pattern. The internal gas volume (lacunal space) of leaves and roots increased along the transect of increased sediment anaerobiosis. Anatomical observations of roots showed a similar trend with enhanced lacunal development at the most anaerobic site. Data collected in field and laboratory experiments in which the hydrogen sulfide concentration surrounding the roots and rhizomes was enhanced showed physiological adaptations characteristic of tolerance to anaerobiosis. The collective data indicate that Zostera marina is capable of responding to markedly different microenvironments.

Rhizosphere O2 dynamics in young Zostera marina and Ruppia maritima

2015 ◽  
Vol 518 ◽  
pp. 95-105 ◽  
Author(s):  
Z Jovanovic ◽  
MØ Pedersen ◽  
M Larsen ◽  
E Kristensen ◽  
RN Glud
Keyword(s):  
Zostera Marina ◽  
Ruppia Maritima

Eelgrass (Zostera marina) restoration on the west coast of Sweden using seeds

2016 ◽  
Vol 546 ◽  
pp. 31-45 ◽  
Author(s):  
E Infantes ◽  
L Eriander ◽  
PO Moksnes
Keyword(s):  
West Coast ◽  
Zostera Marina ◽  
The West

Seasonal effects on grain yield of long-term plant nutrition experiments at Keszthely, Hungary

2006 ◽  
Vol 34 (1) ◽  
pp. 151-154 ◽  
Author(s):  
Katalin Debreczeni ◽  
Sándor Hoffmann ◽  
Katalin Berecz
Keyword(s):  
Grain Yield ◽  
Plant Nutrition ◽  
Seasonal Effects

Truck Weight Enforcement Measures of Effectiveness: Development and Software Application

1998 ◽  
Vol 1643 (1) ◽  
pp. 152-160 ◽  
Author(s):  
F. R. Hanscom ◽  
M. W. Goelzer
Keyword(s):  
Software Tool ◽  
Field Evaluation ◽  
Seasonal Effects ◽  
Data Sets ◽  
Activity Data ◽  
Software Application ◽  
Enforcement Effort ◽  
Measures Of Effectiveness ◽  
Truck Weight ◽  
Enforcement Activity

A software tool was developed to determine what is accomplished as the result of truck weight enforcement efforts. Traditionally applied measures (e.g., numbers of trucks weighed and citations issued) have simply provided indications of enforcement effort. These previously applied measures failed to provide results in terms of real enforcement objectives, such as deterring overweight trucks and minimizing pavement wear and tear. Consequently the need exists to develop and validate truck weight enforcement measures of effectiveness (MOE). MOEs were developed via a series of analytical procedures. They were subsequently validated in a comprehensive four-state field evaluation. Matched (weigh-in-motion) (WIM) data sets, collected under controlled baseline and enforcement conditions, were analyzed to determine the sensitivity of candidate MOEs to actual enforcement activity. Data collection conditions were controlled in order to avoid contamination from hour-of-day, day-of-week, and seasonal effects. The following MOEs, were validated on the basis of their demonstrated sensitivity to truck weight enforcement objectives and the presence of enforcement activity: (1) severity of overweight violations, (2) proportion of overweight trucks, (3) average equivalent single-axle load (ESAL), (4) excess ESALs, and (5) bridge formula violations. These measures are sensitive to legal load-limit compliance objectives of truck weight enforcement procedures as well as the potential for overweight trucks to produce pavement deterioration. The software User Guide that statistically compares calculated MOEs between observed enforcement conditions is described in this paper. The User Guide also allows users to conduct an automated pavement design life analysis estimating, the theoretical pavement-life effect resulting from the observed enforcement activity.

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