scholarly journals Distributional patterns and diets of four species of sea urchins in giant kelp forest (Macrocystis pyrifera) of Puerto Toro, Navarino Island, Chile

1984 ◽  
Vol 19 ◽  
pp. 55-63 ◽  
Author(s):  
JA Vásquez ◽  
JC Castilla ◽  
B Santelices
Keyword(s):  
Sea Urchins ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Giant Kelp ◽  
Distributional Patterns

scholarly journals Sea urchins mediate the availability of kelp detritus to benthic consumers

2019 ◽  
Vol 286 (1906) ◽  
pp. 20190846 ◽  
Author(s):  
Christie E. Yorke ◽  
Henry M. Page ◽  
Robert J. Miller
Keyword(s):  
Food Webs ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Mesocosm Experiment ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Trophic Role ◽  
Benthic Consumers

Detritus can fundamentally shape and sustain food webs, and shredders can facilitate its availability. Most of the biomass of the highly productive giant kelp, Macrocystis pyrifera , becomes detritus that is exported or falls to the seafloor as litter. We hypothesized that sea urchins process kelp litter through shredding, sloppy feeding and egestion, making kelp litter more available to benthic consumers. To test this, we conducted a mesocosm experiment in which an array of kelp forest benthic consumers were exposed to 13 C- and 15 N-labelled Macrocystis with or without the presence of sea urchins, Strongylocentrotus purpuratus . Our results showed that several detritivore species consumed significant amounts of kelp, but only when urchins were present. Although they are typically portrayed as antagonistic grazers in kelp forests, sea urchins can have a positive trophic role, capturing kelp litter before it is exported and making it available to a suite of benthic detritivores.

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.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

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