scholarly journals Direct measurements of light attenuation by epiphytes on eelgrass Zostera marina

2002 ◽  
Vol 238 ◽  
pp. 73-79 ◽  
Author(s):  
MJ Brush ◽  
SW Nixon
Keyword(s):  
Zostera Marina ◽  
Light Attenuation ◽  
Direct Measurements

scholarly journals Absence of recovery in a degraded eelgrass (Zostera Marina) bed in Nova Scotia, Canada: Results from a transplant study

2020 ◽  
Vol 50 (2) ◽  
pp. 251
Author(s):  
Erin Wilson ◽  
David J. Garbary
Keyword(s):  
Nova Scotia ◽  
Zostera Marina ◽  
Light Attenuation ◽  
Carcinus Maenas ◽  
Control Site ◽  
Green Crab ◽  
Eastern Canada ◽  
Growth And Survival ◽  
Negative Effect ◽  
European Green Crab

By the early 2000s, the invasion of the European green crab (Carcinus maenas) had caused a severe decline of eelgrass (Zostera marina) beds in eastern Canada. The formerly lush eelgrass bed in Benoit Cove, Nova Scotia, was extirpated by 2009 and has subsequently failed to recover. The objective of our study was to establish if Benoit Cove (BC) has reached a new equilibrium in which eelgrass cannot recolonize. From July 3 - August 29, 2018, we transplanted eelgrass using frames and monitored eelgrass growth and survival relative to the nearby donor (control) site in Tracadie West Arm (TWA) that had an extensive eelgrass meadow with over 95% cover. Transplant survival was 91.6% and 15.4% for TWA and BC, respectively (P < 0.001). Above-ground growth declined at both sites, and could be associated with high summer water temperatures and/or extreme epiphytism. Sediments at both sites had high silt composition (> 28%), and the absence of a macrophyte canopy lead to increased light attenuation in BC in moderate wind and tidal currents. The low density of green crabs in both BC and TWA (0.01 m-2 and 0.08 m-2, respectively), and the apparently healthy eelgrass bed in TWA, suggest that green crabs are not having a negative effect on eelgrass in this system and are not responsible for the lack of recolonization of eelgrass in BC.Keywords: Atlantic Canada; eelgrass bed; European green crab; transplant; Zostera marina

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

Predicting cold-water bleaching in corals: role of temperature, and potential integration of light exposure

2020 ◽  
Vol 642 ◽  
pp. 133-146
Author(s):  
PC González-Espinosa ◽  
SD Donner
Keyword(s):  
Coral Bleaching ◽  
Cold Water ◽  
Light Exposure ◽  
Light Attenuation ◽  
Florida Keys ◽  
Cold Temperature ◽  
Warm Water ◽  
Coral Tissue ◽  
Effect Of Temperature ◽  
Type I

Warm-water growth and survival of corals are constrained by a set of environmental conditions such as temperature, light, nutrient levels and salinity. Water temperatures of 1 to 2°C above the usual summer maximum can trigger a phenomenon known as coral bleaching, whereby disruption of the symbiosis between coral and dinoflagellate micro-algae, living within the coral tissue, reveals the white skeleton of coral. Anomalously cold water can also lead to coral bleaching but has been the subject of limited research. Although cold-water bleaching events are less common, they can produce similar impacts on coral reefs as warm-water events. In this study, we explored the effect of temperature and light on the likelihood of cold-water coral bleaching from 1998-2017 using available bleaching observations from the Eastern Tropical Pacific and the Florida Keys. Using satellite-derived sea surface temperature, photosynthetically available radiation and light attenuation data, cold temperature and light exposure metrics were developed and then tested against the bleaching observations using logistic regression. The results show that cold-water bleaching can be best predicted with an accumulated cold-temperature metric, i.e. ‘degree cooling weeks’, analogous to the heat stress metric ‘degree heating weeks’, with high accuracy (90%) and fewer Type I and Type II errors in comparison with other models. Although light, when also considered, improved prediction accuracy, we found that the most reliable framework for cold-water bleaching prediction may be based solely on cold-temperature exposure.

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