Effects of removing sea urchins (Strongylocentrotus droebachiensis): Stability of the barren state and succession of kelp forest recovery in the east Atlantic

Oecologia ◽  
1996 ◽  
Vol 105 (4) ◽  
pp. 524-536 ◽  
Author(s):  
Hans Petter Leinaas ◽  
Hartvig Christie
Keyword(s):  
Sea Urchins ◽  
Kelp Forest ◽  
Strongylocentrotus Droebachiensis ◽  
Forest Recovery ◽  
East Atlantic

Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards
Keyword(s):  
Field Experiments ◽  
Local Community ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Forest Recovery ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Combined Effects ◽  
Life Stages ◽  
Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

Transient dynamics during kelp forest recovery from fishing across multiple trophic levels

2021 ◽  
Author(s):  
Robert P. Dunn ◽  
Jameal F. Samhouri ◽  
Marissa L. Baskett
Keyword(s):  
Kelp Forest ◽  
Trophic Levels ◽  
Forest Recovery ◽  
Transient Dynamics

Evidence for Association of Vibrio Echinoideorum with Tissue Necrosis on Body Shell of the Green Sea Urchin Strongylocentrotus Droebachiensis

2021 ◽  
Author(s):  
Jonathan Hira ◽  
Klara Stensvåg
Keyword(s):  
Sea Urchin ◽  
Virulence Genes ◽  
Vibrio Vulnificus ◽  
Sea Urchins ◽  
Opportunistic Pathogen ◽  
Significant Degree ◽  
Strongylocentrotus Droebachiensis ◽  
Host Immune System ◽  
Progressive Development ◽  
Green Sea Urchin

Abstract “Sea urchin lesion syndrome” is known as sea urchins disease with the progressive development of necrotic epidermal tissue and loss of external organs, including appendages on the outer body surface. Recently, a novel strain, Vibrio echinoideorum has been isolated from the lesions of green sea urchin (Strongylocentrotus droebachiensis), an economically important mariculture species in Norway. V. echinoideorum has not been reported elsewhere in association of with green sea urchin lesion syndrome. Therefore, in this study, an immersion based bacterial challenge experiment was performed to expose sea urchins (wounded and non-wounded) to V. echinoideorum, thereby mimicking a nearly natural host-pathogen interaction under controlled conditions. This infection experiment demonstrated that only the injured sea urchins developed the lesion to a significant degree when exposed to V. echinoideorum. Pure cultures of the employed bacterial strain was recovered from the infected animals and its identity was confirmed by the MALDI-TOF MS spectra profiling. Additionally, the hemolytic phenotype of V. echinoideorum substantiated its virulence potential towards the host, and this was also supported by the cytolytic effect on red spherule cells of sea urchins. Furthermore, the genome sequence of V. echinoideorum was assumed to encode potential virulence genes and were subjected for in silico comparison with the established virulence factors of Vibrio vulnificus and Vibrio tasmaniensis. This comparative virulence profile provided novel insights about virulence genes and their putative functions related to chemotaxis, adherence, invasion, evasion of the host immune system, and damage of host tissue and cells. Thus, it supports the pathogenicity of V. echinoideorum. In conclusion, the interaction of V. echinoideorum with injured sea urchins appears to be essential for the development of lesion syndrome and therefore, revealing its potentiality as an opportunistic pathogen.

Effect of temperature on somatic growth and survivorship of early post-settled green sea urchins, Strongylocentrotus droebachiensis (Müller)

2005 ◽  
Vol 36 (6) ◽  
pp. 600-609 ◽  
Author(s):  
Christopher M Pearce ◽  
Sean W Williams ◽  
Fu Yuan ◽  
John D Castell ◽  
Shawn M C Robinson
Keyword(s):  
Sea Urchins ◽  
Somatic Growth ◽  
Strongylocentrotus Droebachiensis ◽  
Effect Of Temperature

Geographic and environmental factors affecting the distribution of kelp beds and barren grounds and changes in biota associated with kelp reduction at sites along the Norwegian coast

1997 ◽  
Vol 54 (12) ◽  
pp. 2872-2887 ◽  
Author(s):  
Knut Sivertsen
Keyword(s):  
Environmental Factors ◽  
Sea Urchins ◽  
Strongylocentrotus Droebachiensis ◽  
The Arctic ◽  
Laminaria Hyperborea ◽  
Factors Affecting ◽  
Kelp Beds ◽  
The Mean ◽  
Transition Areas ◽  
Barren Grounds

Sites at 244 locations along the west and north Norwegian coasts were investigated to evaluate whether kelp (Laminaria hyperborea) beds had been overgrazed by the sea urchins Strongylocentrotus droebachiensis and Echinus esculentus in the years 1981-1992. Barren ground communities were found in sheltered and moderately wave-exposed areas mainly in the inner and middle archipelago from Nordmøre (63°N) northwards. Densities of large-sized (adult and intermediate) L. hyperborea were 20.7 individuals ·m-2 in kelp beds and 9.7 individuals ·m-2 in transition areas. Juvenile Laminaria spp. were present at densities of 23.9 individuals ·m-2 in kelp beds, 3.6 individuals ·m-2 in transition areas, 0.0 individuals ·m-2 in barren grounds, and 59.1 individuals ·m-2 in kelp-harvested locations. Both the densities and the mean size of S. droebachiensis in barren grounds decreased northwards. The mean densities were 52.2 and 26.1 individuals ·m-2 for the areas south and north of the Arctic Circle, respectively. Multivariate analysis (CANOCO) showed that seven ``environmental'' factors (i.e., kelp depth gradient, distance (latitude), time of sampling, nematode infection in S. droebachiensis, wave exposure, coastal gradient, and substratum) contributed significantly to variability in the distribution of kelp beds and barren grounds. Species in hard-bottom communities in shallow waters could be divided into three distinct BIOTA.

N2-fixing vibrios isolated from the gastrointestinal tract of sea urchins

1981 ◽  
Vol 27 (3) ◽  
pp. 311-317 ◽  
Author(s):  
M. L. Guerinot ◽  
D. G. Patriquin
Keyword(s):  
Gastrointestinal Tract ◽  
Sea Urchins ◽  
Anaerobic Bacteria ◽  
Strongylocentrotus Droebachiensis ◽  
Physiological Traits ◽  
Biochemical Characteristics ◽  
Facultatively Anaerobic ◽  
The Family ◽  
Vibrio Genus ◽  
Facultatively Anaerobic Bacteria

Facultatively anaerobic bacteria, capable of fixing N2 anaerobically or at low O2 concentrations, were isolated from the gastrointestinal tracts of temperate (Strongylocentrotus droebachiensis) and tropical (Tripneustes ventricosus) sea urchins. Morphological and biochemical characteristics, as well as the guanine plus cytosine content of their DNA (45.9 and 48.4 mol%), place these isolates in the genus Vibrio Pacini 1865 in the family Vibrionaceae. Members of this family have not previously been shown to fix N2. These isolates are not identical to any described species in the Vibrio genus and can be distinguished by a combination of biochemical and physiological traits.

Effect of dietary lipids on fatty acid composition and metabolism in juvenile green sea urchins (Strongylocentrotus droebachiensis)

Aquaculture ◽  
2004 ◽  
Vol 242 (1-4) ◽  
pp. 417-435 ◽  
Author(s):  
John D. Castell ◽  
Eddy J. Kennedy ◽  
Shawn M.C. Robinson ◽  
G.Jay Parsons ◽  
Tammy J. Blair ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Sea Urchins ◽  
Dietary Lipids ◽  
Strongylocentrotus Droebachiensis
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