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John M Lawrence - One of the best experts on this subject based on the ideXlab platform.
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interactive effects of temperature and nutritional condition on the energy budgets of the sea urchins Arbacia punctulata and lytechinus variegatus echinodermata echinoidea
Journal of the Marine Biological Association of the United Kingdom, 2006Co-Authors: Sophie K Hill, John M LawrenceAbstract:Arbacia punctulata and Lytechinus variegatus are widely distributed echinoid species in shallow water in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico that seem to have diierent life history strategies. We evaluated the eiect of two types of stress (high temperature and starvation) on gonad production and scope for growth. We hypothesized that A. punctulata has a stress tolerant life strategy and would be more tolerant to stress and L. variegatus has a competitive ^ ruderal strategy and would be less tolerant to stress. Gonad production by A. punctulata was not as greatly aiected by temperature as L. variegatus, suggesting the hypothesis was correct. Arbacia punctulata had a signi¢cantly higher excretion rate indicating greater energy allocation to maintenance than production. Lytechinus variegatus had a signi¢cantly greater consumption rate but did not absorb signi¢cantly more energy. Arbacia punctulata compensated for its lower food consumption by a higher absorption e⁄ciency. Measured energy expenditure and calculated scope for growth did not diier. However, the percentage change in energy absorbed and energy expenditure was greater for L. variegatus than for A. punctulata with a change in temperature. Feeding had a greater eiect on production than temperature suggesting that the biotic stress of low food availability is more important than an abiotic stress such as temperature on energy budgets.
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diets and coexistence of the sea urchins lytechinus variegatus and Arbacia punctulata echinodermata along the central florida gulf coast
Marine Ecology Progress Series, 2005Co-Authors: Janessa Cobb, John M LawrenceAbstract:The basis for coexistence of similar species is fundamental in community ecology. One mechanism for coexistence is differentiation of diets. Lytechinus variegatus and Arbacia punctulata coexist in different microhabitats along the Florida gulf coast. Their great difference in morphology might affect their choice of microhabitats and diet. We analyzed diets of both species at 1 offshore and 1 nearshore site where both occurred in relatively equal numbers, an offshore site dominated by A. punctulata and an offshore site dominated by L. variegatus. Gut contents were analyzed to deter- mine the diet. A. punctulata prim. consumed sessile invertebrates except on dates when algal avail- ability was higher than normal. L. variegatus primarily consumed macroflora except on dates when macroflora was extremely limited. Electivity indices revealed no strong preferences for particular species of algae, although L. variegatus consumed many drift species. A. punctulata and L. variega- tus both fed in a random manner, although they avoided particular species of algae known to contain high concentrations of secondary metabolites. The diet of A. punctulata was correlated with algae only over rubble outcroppings at the offshore site with the highest biomass. Diets of offshore popula- tions were more similar to each other, regardless of the presence of conspecifics, than to those of populations at Caspersen Beach (nearshore site). As diets do not overlap, distribution of individuals at a location would not be affected by interspecific competition for food. However, intraspecific competition may be high due to low site productivity.
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habitats and characteristics of the sea urchins lytechinus variegatus and Arbacia punctulata echinodermata on the florida gulf coast shelf
Marine Ecology, 2003Co-Authors: Sophie K Hill, John M LawrenceAbstract:Abstract Lytechinus variegatus and Arbacia punctulata have been studied primarily in inshore, shallow-water areas. However, they are abundant in deeper waters on the Florida gulf-coast shelf and seem important components of the benthic communities there. Lytechinus variegatus occurs alone on sand bottoms and A. punctulata occurs alone on rubble bottoms in these deeper waters. The species also co-occur there on heterogeneous bottoms, each in a distinct microhabitat with A. punctulata on rubble and L. variegatus on surrounding sand. Characteristics of the sea urchins in these different deeper-water habitat types and at one nearshore site with a heterogeneous rubble-sand bottom were compared. Over the 2-year study, offshore individuals of both species had low gut and gonad indices and the maximum size of individuals did not change. This suggests food limitation and low production. Offshore, A. punctulata had a higher Aristotle's lantern index and lower gut and gonad indices in populations where it co-occurred with L. variegatus compared to populations where it occurred alone. The Aristotle's lantern index of L. variegatus did not differ among the offshore sites. Neither species seemed food limited at the nearshore site. Although productivity is lower at the offshore sites, both species extend their distribution and reproduction potential by existing there.
Sophie K Hill - One of the best experts on this subject based on the ideXlab platform.
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interactive effects of temperature and nutritional condition on the energy budgets of the sea urchins Arbacia punctulata and lytechinus variegatus echinodermata echinoidea
Journal of the Marine Biological Association of the United Kingdom, 2006Co-Authors: Sophie K Hill, John M LawrenceAbstract:Arbacia punctulata and Lytechinus variegatus are widely distributed echinoid species in shallow water in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico that seem to have diierent life history strategies. We evaluated the eiect of two types of stress (high temperature and starvation) on gonad production and scope for growth. We hypothesized that A. punctulata has a stress tolerant life strategy and would be more tolerant to stress and L. variegatus has a competitive ^ ruderal strategy and would be less tolerant to stress. Gonad production by A. punctulata was not as greatly aiected by temperature as L. variegatus, suggesting the hypothesis was correct. Arbacia punctulata had a signi¢cantly higher excretion rate indicating greater energy allocation to maintenance than production. Lytechinus variegatus had a signi¢cantly greater consumption rate but did not absorb signi¢cantly more energy. Arbacia punctulata compensated for its lower food consumption by a higher absorption e⁄ciency. Measured energy expenditure and calculated scope for growth did not diier. However, the percentage change in energy absorbed and energy expenditure was greater for L. variegatus than for A. punctulata with a change in temperature. Feeding had a greater eiect on production than temperature suggesting that the biotic stress of low food availability is more important than an abiotic stress such as temperature on energy budgets.
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habitats and characteristics of the sea urchins lytechinus variegatus and Arbacia punctulata echinodermata on the florida gulf coast shelf
Marine Ecology, 2003Co-Authors: Sophie K Hill, John M LawrenceAbstract:Abstract Lytechinus variegatus and Arbacia punctulata have been studied primarily in inshore, shallow-water areas. However, they are abundant in deeper waters on the Florida gulf-coast shelf and seem important components of the benthic communities there. Lytechinus variegatus occurs alone on sand bottoms and A. punctulata occurs alone on rubble bottoms in these deeper waters. The species also co-occur there on heterogeneous bottoms, each in a distinct microhabitat with A. punctulata on rubble and L. variegatus on surrounding sand. Characteristics of the sea urchins in these different deeper-water habitat types and at one nearshore site with a heterogeneous rubble-sand bottom were compared. Over the 2-year study, offshore individuals of both species had low gut and gonad indices and the maximum size of individuals did not change. This suggests food limitation and low production. Offshore, A. punctulata had a higher Aristotle's lantern index and lower gut and gonad indices in populations where it co-occurred with L. variegatus compared to populations where it occurred alone. The Aristotle's lantern index of L. variegatus did not differ among the offshore sites. Neither species seemed food limited at the nearshore site. Although productivity is lower at the offshore sites, both species extend their distribution and reproduction potential by existing there.
Janessa Cobb - One of the best experts on this subject based on the ideXlab platform.
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diets and coexistence of the sea urchins lytechinus variegatus and Arbacia punctulata echinodermata along the central florida gulf coast
Marine Ecology Progress Series, 2005Co-Authors: Janessa Cobb, John M LawrenceAbstract:The basis for coexistence of similar species is fundamental in community ecology. One mechanism for coexistence is differentiation of diets. Lytechinus variegatus and Arbacia punctulata coexist in different microhabitats along the Florida gulf coast. Their great difference in morphology might affect their choice of microhabitats and diet. We analyzed diets of both species at 1 offshore and 1 nearshore site where both occurred in relatively equal numbers, an offshore site dominated by A. punctulata and an offshore site dominated by L. variegatus. Gut contents were analyzed to deter- mine the diet. A. punctulata prim. consumed sessile invertebrates except on dates when algal avail- ability was higher than normal. L. variegatus primarily consumed macroflora except on dates when macroflora was extremely limited. Electivity indices revealed no strong preferences for particular species of algae, although L. variegatus consumed many drift species. A. punctulata and L. variega- tus both fed in a random manner, although they avoided particular species of algae known to contain high concentrations of secondary metabolites. The diet of A. punctulata was correlated with algae only over rubble outcroppings at the offshore site with the highest biomass. Diets of offshore popula- tions were more similar to each other, regardless of the presence of conspecifics, than to those of populations at Caspersen Beach (nearshore site). As diets do not overlap, distribution of individuals at a location would not be affected by interspecific competition for food. However, intraspecific competition may be high due to low site productivity.
John J Stegeman - One of the best experts on this subject based on the ideXlab platform.
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nitric oxide synthase sequences in the marine fish stenotomus chrysops and the sea urchin Arbacia punctulata and phylogenetic analysis of nitric oxide synthase calmodulin binding domains
Comparative Biochemistry and Physiology B, 2001Co-Authors: Thomas M Mariano, Diane E Heck, Jeffrey D Laskin, John J StegemanAbstract:Abstract The phylogenetic distribution and structural diversity of the nitric oxide synthases (NOS) remain important and issues that are little understood. We present sequence information, as well as phylogenetic analysis, for three NOS cDNAs identified in two non-mammalian species: the vertebrate marine teleost fish Stenotomus chrysops (scup) and the invertebrate echinoderm Arbacia punctulata (sea urchin). Partial gene sequences containing the well-conserved calmodulin (CaM)-binding domain were amplified by RT-PCR. Identical 375-bp cDNAs were amplified from scup brain, heart, liver and spleen; this sequence shares 82% nucleic acid and 91% predicted amino acid identity with the corresponding region of human neuronal NOS. A 387-bp cDNA was amplified from sea urchin ovary and testes; this sequence shares 72% nucleic acid identity and 65% deduced amino acid identity with human neuronal NOS. A second cDNA of 381 bp was amplified from sea urchin ovary and it shares 66% nucleic acid and 57% deduced amino acid identity with the first sea urchin sequence. Together with earlier reports of neuronal and inducible NOS sequences in fish, these data indicate that multiple NOS isoforms exist in non-mammalian species. Phylogenetic analysis of these sequences confirms the conserved nature of NOS, particularly of the calmodulin-binding domains.
Thomas M Mariano - One of the best experts on this subject based on the ideXlab platform.
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nitric oxide synthase sequences in the marine fish stenotomus chrysops and the sea urchin Arbacia punctulata and phylogenetic analysis of nitric oxide synthase calmodulin binding domains
Comparative Biochemistry and Physiology B, 2001Co-Authors: Thomas M Mariano, Diane E Heck, Jeffrey D Laskin, John J StegemanAbstract:Abstract The phylogenetic distribution and structural diversity of the nitric oxide synthases (NOS) remain important and issues that are little understood. We present sequence information, as well as phylogenetic analysis, for three NOS cDNAs identified in two non-mammalian species: the vertebrate marine teleost fish Stenotomus chrysops (scup) and the invertebrate echinoderm Arbacia punctulata (sea urchin). Partial gene sequences containing the well-conserved calmodulin (CaM)-binding domain were amplified by RT-PCR. Identical 375-bp cDNAs were amplified from scup brain, heart, liver and spleen; this sequence shares 82% nucleic acid and 91% predicted amino acid identity with the corresponding region of human neuronal NOS. A 387-bp cDNA was amplified from sea urchin ovary and testes; this sequence shares 72% nucleic acid identity and 65% deduced amino acid identity with human neuronal NOS. A second cDNA of 381 bp was amplified from sea urchin ovary and it shares 66% nucleic acid and 57% deduced amino acid identity with the first sea urchin sequence. Together with earlier reports of neuronal and inducible NOS sequences in fish, these data indicate that multiple NOS isoforms exist in non-mammalian species. Phylogenetic analysis of these sequences confirms the conserved nature of NOS, particularly of the calmodulin-binding domains.