Salinity-related polymorphism in the brackish-water diatom Cyclotella cryptica

1971 ◽  
Vol 49 (8) ◽  
pp. 1285-1289 ◽  
Author(s):  
Mary E. Schultz
Keyword(s):  
Life History ◽  
Brackish Water ◽  
Valve Morphology ◽  
Life History Stages ◽  
Low Salinity ◽  
Full Strength ◽  
Polymorphic Species ◽  
Pattern Characteristic ◽  
Cyclotella Cryptica

The brackish-water diatom Cyclotella cryptica is a polymorphic species. Nine clones are capable of producing the valve pattern characteristic of the species C. meneghiniana, as well as the C. cryptica pattern. A study of the effects of salinity and freshwater conditions on the morphology of the valve shows that the cryptica pattern is produced in salinities of about 4.3‰ to full-strength seawater, 28.7‰. The "meneghiniana" pattern is the freshwater or low salinity (1.4‰) form. Characteristics of the valve morphology and life history stages which distinguish C. cryptica from C. meneghiniana and Cyclotella sp., clone 03A, are presented and discussed.

scholarly journals The movement ecology of seagrasses

2014 ◽  
Vol 281 (1795) ◽  
pp. 20140878 ◽  
Author(s):  
Kathryn McMahon ◽  
Kor-jent van Dijk ◽  
Leonardo Ruiz-Montoya ◽  
Gary A. Kendrick ◽  
Siegfried L. Krauss ◽  
...  
Keyword(s):  
Life History ◽  
Clonal Growth ◽  
Movement Ecology ◽  
Future Research ◽  
The Novel ◽  
Long Distance ◽  
Spatial And Temporal Scales ◽  
Life History Stages ◽  
Research Areas ◽  
Time Movement

A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.

scholarly journals Sublethal Effects of Crude Oil and Chemical Dispersants on Multiple Life History Stages of the Eastern Oyster, Crassostrea virginica

2020 ◽  
Vol 8 (10) ◽  
pp. 808
Author(s):  
Sara M. Garcia ◽  
Kevin T. Du Clos ◽  
Olivia H. Hawkins ◽  
Brad J. Gemmell
Keyword(s):  
Life History ◽  
Crude Oil ◽  
Crassostrea Virginica ◽  
Sublethal Effects ◽  
Oil Pollution ◽  
Eastern Oyster ◽  
Clearance Rates ◽  
Important Species ◽  
Life History Stages ◽  
Oil Exposure

The eastern oyster Crassostrea virginica is an ecologically and economically important species that is vulnerable to oil pollution. We assessed sublethal effects of soluble fractions of crude oil alone (WAF) and crude oil in combination with Corexit 9500 dispersant (CEWAF) on oysters at three life history stages. Veliger swimming, pediveliger settlement, and adult clearance rates were quantified after 24 h exposures to the contaminants. Veliger swimming speeds were not significantly impacted by 24 h exposures to WAF or CEWAF. A larger proportion of veligers were inactive following WAF and CEWAF exposure as compared to the control, but the effect was greater for pediveligers, and pediveliger settlement in the highest concentration CEWAF treatment decreased by 50% compared to controls. Thus, pediveligers may be particularly vulnerable to oil exposure. In the adults, we found significant clearance rates reductions that persisted 33 days after acute exposure to CEWAF. Knowledge of sublethal effects of oil and dispersant at multiple life history stages aids understanding of how this important species will respond to an oil spill.

Significance of Egg and Larval Size to Recruitment Variability of Temperate Marine Fish

1991 ◽  
Vol 48 (10) ◽  
pp. 1820-1828 ◽  
Author(s):  
Pierre Pepin ◽  
Ransom A. Myers
Keyword(s):  
Life History ◽  
Marine Fish ◽  
Early Life ◽  
Univariate Analysis ◽  
Early Life History ◽  
Fish Populations ◽  
Larval Size ◽  
Larval Phase ◽  
Life History Stages ◽  
Recruitment Variability

Recruitment variability is commonly associated with fluctuations in abundance of marine fish populations. Previous studies have focussed on stock-specific correlative or mechanistic models or on comparisons of recruitment variations of several stocks or species. The purpose of this study is to determine whether recruitment variability of commercial marine fish populations is associated with either size or the duration of early life history stages. The analysis was performed with data from 86 stocks representing 21 species of commercial marine fish. Univariate analysis shows that neither egg size nor the length at hatch is significantly correlated with recruitment variability. The change in length during the larval phase, which is representative of the duration of the stage, is significantly positively correlated with recruitment variability. Multivariate analysis shows that recruitment variability increases with increasing length at metamorphosis but that recruitment variability is poorly associated with length at hatch. The degree of serial correlation is related to the relative duration of egg and larval stages. The results clearly indicate that recruitment variability is linked to characteristics of early life history stages.

Disturbance and tropical pioneer species: Patterns of association across life history stages

2012 ◽  
Vol 277 ◽  
pp. 54-66 ◽  
Author(s):  
Uromi M. Goodale ◽  
Mark S. Ashton ◽  
Graeme P. Berlyn ◽  
Timothy G. Gregoire ◽  
B.M.P. Singhakumara ◽  
...  
Keyword(s):  
Life History ◽  
Pioneer Species ◽  
Life History Stages

scholarly journals Addressing fish-passage issues at hydropower and irrigation infrastructure projects in Indonesia

2018 ◽  
Vol 69 (12) ◽  
pp. 1805 ◽  
Author(s):  
Lee J. Baumgartner ◽  
Arif Wibowo
Keyword(s):  
Life History ◽  
Fish Passage ◽  
Mitigation Measures ◽  
Migratory Fish ◽  
Tropical Island ◽  
Life History Stages ◽  
Barrier Effects ◽  
Sumatra Island ◽  
Irrigation Infrastructure

Development activities threaten the long-term sustainability of tropical floodplain systems. The construction of dams, weirs, irrigation infrastructure and regulators affect connectivity among habitats and can facilitate rapid declines in riverine biota, especially fish. Indonesia is a tropical island country with an abundance of monsoonal rivers. Massive expansions in hydropower and irrigation infrastructure are planned over the next two decades and mitigation measures will be needed to protect migratory fish. Most Indonesian freshwater fish need to migrate among habitats to complete essential life-history stages. So, strategies are urgently needed to mitigate the barrier effects of river infrastructure to ensure the long-term sustainability of river fishes. A common tool used worldwide is the construction of upstream and downstream fish passes. Only two fish passes exist in Indonesia. One at Perjaya Irrigation Dam on the Komering River (Sumatra island) and another on Poso Dam on the Poso River (Sulawesi island). Neither of these structures has been assessed and many other projects are proceeding without considering potential impacts on fisheries. The proposed infrastructure upgrades over the next two decades provide a once-in-a-generation opportunity to ensure that migratory fish are adequately protected into the future.

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