Ecotypic differentiation of Laminaria longicruris in relation to seawater nitrate concentration

Espinoza, J.; Chapman, A. R. O.

doi:10.1007/bf00413924

Cited by 76 publications

(37 citation statements)

References 20 publications

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“…2 to 4). A similar lack of N-storage was found in temperate kelps from nutrient-rich waters (Anderson et al 1981, Gagne et al 1982, Espinoza & Chapman 1983. The critical N-content at which growth became N-limited was approximately 1.9% dry wt for H. grandifolius, only marginally smaller than the highest value for N-replete plants (2.2%).…”

Section: Discussionsupporting

confidence: 66%

“…Many populations of temperate kelps are seasonaliy subjected to low Nsupply and have the ability to accumulate N-stores to survive these penods. L. s a c c h a~a from St. Margaret's Bay, Nova Scotia, were exposed to low NO3-concentrations for approxirnately 8 mo of the year (Chapman & Craigie 1977, Anderson et al 1981, Gagne et al 1982, Espinoza & Chapman 1983). When internal NO3-pools were depleted, growth rates slowed, but plants did not demonstrate negative growth rates.…”

Section: Discussionmentioning

confidence: 99%

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Effects of concurrent low temperature and low nitrogen supply on polar and temperate seaweeds

Korb¹,

Gerard²

2000

Mar. Ecol. Prog. Ser.

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Antarctic and arctic marine waters have simiiar near-freezing temperatures, but differ greatly in dissolved inorganic nitrogen (DIN) availabiiity. Antarctic algae have high DIN supply yearround; arctic algae are N-iimited during the Summer. Temperate algae experience low temperatures and low DIN supply on a seasonal basis, but never concurrently. Nitrogen supply iniluences the abiiity of algae to achieve the high enzyme activities necessary for cold a c c h a t i o n . The present study compared N-ailocation strategies of antarctic, arctic, and temperate seaweeds grown under N-replete and N-iimited conditions at near-freezing temperature. Sporophytes of the antarctic endemic, Himantothdus grandifolius, did not store NO3-, had small pools of nitrogenous compounds, and were unable to sustain growth for longer than 1 mo under N-iimitation. However, N-starved plants with negative growth rates exhibited chlorophyll fluorescence ratios (FJF,) simiiar to those of N-replete plants, and photosynthetic rates remained positive, suggesting that PSI1 reaction centres (RCII) were functioning efficiently. In contrast, the arctic endemic, Laminaria solidungula, maintained relatively high growth rates dunng 9 mo of N-starvation. The arctic kelp utilised both internal N O 3 p 0 0 l~ and organic nitrogenous components, such as protein and chlorophyll, to support growth. Despite declines in the density of RCII and photosynthetic capacity, N-iimited L. solidungula continued to accurnulate carbon reserves. Like the arctic plants, temperate L. saccharina from the Atlantic coast of Maine had internal reserves of NO3-and organic compounds that provided the initial N-source for growth under low external N-supply. The internal N-reserves were depleted fairly rapidly, however, and the temperate kelp showed simultaneous reductions in growth rate, photosynthetic capacity, and FJF, after only 3 mo under low N-supply. Overall, the arctic species alone has an N-aliocation strategy for surviving long penods of concurrent low temperature and low N-supply. The antarctic species appears to be primarily adapted to maintaining photosynthesis and growth under low light and low temperature, rather than low DIN supply. The temperate species is poorly adapted to survive prolonged penods of both low N and low temperature, even though ecotypes of this species extend into the Arctic.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Effects of concurrent low temperature and low nitrogen supply on polar and temperate seaweeds

Korb¹,

Gerard²

2000

Mar. Ecol. Prog. Ser.

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“…In contrast, sublethal growth rates (Innes, 1988}, copper tolerance (Russell & Morris, 1970}, salinity tolerance {Russell & Bolton, 1975, daylength response {Lfining, 1980}, photophysiology (Gerard, 1988) and nutrient physiology (Espinosa & Chapman, 1983) all may vary widely within narrow latitudinal ranges.…”

Section: Discussionmentioning

confidence: 99%

Thermal ecotypes of amphi-Atlantic algae. I. Algae of Arctic to cold-temperate distribution (Chaetomorpha melagonium, Devaleraea ramentacea andPhycodrys rubens)

Novaczek

Lubbers

Breeman

1990

Helgolander Meeresunters

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Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth and/or survival at temperatures of -20 to 30 ~ When isolates from both western and eastern Atlantic shores were tested side-by-side, it was found that thermal ecotypes may occur in such Arctic algae. Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but Icelandic plants were more sensitive to the lethal temperature of 25 ~ than were more southerly isolates from both east and west. With regard to Devaleraea ramentacea, one Canadian isolate grew extraordinarily well at -2 and 0 ~ and all tolerated temperatures 2-3 ~ higher than the lethal limit (18-20 ~ of isolates from Europe. Concerning Phycodrys rubens, both eastern and western isolates died at 20 ~ but European plants tolerated the lethal high temperature longerl were more sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species, C. melagonium and D. ramentacea, both survived freezing at -5 and -20~ at least for short time periods. C. melagonium was more susceptible than D. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species.

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“…Espinoza & Chapman (1983) collected individuals of Laminaria longicruris from areas of high and low nitrate concentration. Nutrient ecotypes were identified by growth rate and nitrate uptake differences under different nitrate concentrations.…”

Section: Morphological Differentiationmentioning

confidence: 99%

Genetic differentiation among populations of marine algae

Innes

1984

Helgoländer Meeresunters

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Most of the information for genetic differentiation among populations of marine algae is from studies on ecotypic variation. Physiological ecotypes have been described for individuals showing different responses to temperature and salinity conditions. Morphological ecotypes have also been found associated with areas differing in wave exposure or different intertidal positions. Little is known on how genetic variation is organized within and between populations of marine algae. The occurrence of ecotypic variation in some species is evidence for genetic differentiation among populations resulting from selection by the local environment. The rate of dispersal and subsequent gene flow will also affect the level of differentiation among populations. In species with low dispersal, differentiation can arise through chance founder events or random genetic drift. The few studies available have shown that species of algae exhibit a range of dispersal capabilities. This information can be useful for predicting the potential level of genetic differentiation among populations of these species. Crossing experiments with several species of algae have shown that populations separated by a considerable distance can be inteffertile. In some cases individuals from these populations have been found to be morphologically distinct. Crosses have been used to study the genetic basis of this variation and are evidence for genetic differentiation among the populations sampled. Genetic variation of enzyme proteins detected by electrophoresis provides an additional method for measuring genetic variation within and between populations of marine algae. Etectrophoretic methods have previously been used to study systematic problems in algae. However, there have been few attempts to use electrophoretic variation to study the genetic structure of populations of marine algae. This approach is outlined and includes some of the potential problems associated with interpreting electrophoretic data. Studies of electrophoretic variation in natural populations of Enteromorpha linza from Long Island Sound are used as an example. This species was found to reproduce only asexually. Despite a dispersing spore stage, genetic differentiation was found on a microgeographic scale and was correlated with differences in the local environment of some of the populations. Similar studies on other species, and especially sexually reproducing species, will add to a growing understanding of the evolutionary genetics of marine algae.

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Ecotypic differentiation of Laminaria longicruris in relation to seawater nitrate concentration

Cited by 76 publications

References 20 publications

Effects of concurrent low temperature and low nitrogen supply on polar and temperate seaweeds

Effects of concurrent low temperature and low nitrogen supply on polar and temperate seaweeds

Thermal ecotypes of amphi-Atlantic algae. I. Algae of Arctic to cold-temperate distribution (Chaetomorpha melagonium, Devaleraea ramentacea andPhycodrys rubens)

Genetic differentiation among populations of marine algae

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