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Ecological partitioning and diversity in tropical planktonic foraminifera.

Seears HA, Darling KF, Wade CM - BMC Evol. Biol. (2012)

Bottom Line: Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses.We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed.Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biology, University of Nottingham, Nottingham, UK.

ABSTRACT

Background: Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses.

Results: We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations.

Conclusions: We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

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Arabian Sea maps showing the spatial distribution of genetic types of the morphospecies identified along the cruise transect. Their numbers do not necessarily reflect the absolute frequency of morphospecies or genotypes in the water column. The dotted line denotes approx. water mass boundary (higher productivity, high salinity in the north/oligotrophic, low salinity in the south) as determined from Figure 1D & 1E. The number of specimens collected at each station for genetic analysis is indicated by a number. A key to genotypes is provided on each map. * indicates novel sequences obtained from the Arabian Sea cruise (CD148).
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Figure 4: Arabian Sea maps showing the spatial distribution of genetic types of the morphospecies identified along the cruise transect. Their numbers do not necessarily reflect the absolute frequency of morphospecies or genotypes in the water column. The dotted line denotes approx. water mass boundary (higher productivity, high salinity in the north/oligotrophic, low salinity in the south) as determined from Figure 1D & 1E. The number of specimens collected at each station for genetic analysis is indicated by a number. A key to genotypes is provided on each map. * indicates novel sequences obtained from the Arabian Sea cruise (CD148).

Mentions: Analysis of the morphospecies genetic type distribution data (Figure 4) combined with a visual assessment of the bulk assemblage data showed some distinct ecological segregation related to the physical oceanography of the Arabian Sea.


Ecological partitioning and diversity in tropical planktonic foraminifera.

Seears HA, Darling KF, Wade CM - BMC Evol. Biol. (2012)

Arabian Sea maps showing the spatial distribution of genetic types of the morphospecies identified along the cruise transect. Their numbers do not necessarily reflect the absolute frequency of morphospecies or genotypes in the water column. The dotted line denotes approx. water mass boundary (higher productivity, high salinity in the north/oligotrophic, low salinity in the south) as determined from Figure 1D & 1E. The number of specimens collected at each station for genetic analysis is indicated by a number. A key to genotypes is provided on each map. * indicates novel sequences obtained from the Arabian Sea cruise (CD148).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3361484&req=5

Figure 4: Arabian Sea maps showing the spatial distribution of genetic types of the morphospecies identified along the cruise transect. Their numbers do not necessarily reflect the absolute frequency of morphospecies or genotypes in the water column. The dotted line denotes approx. water mass boundary (higher productivity, high salinity in the north/oligotrophic, low salinity in the south) as determined from Figure 1D & 1E. The number of specimens collected at each station for genetic analysis is indicated by a number. A key to genotypes is provided on each map. * indicates novel sequences obtained from the Arabian Sea cruise (CD148).
Mentions: Analysis of the morphospecies genetic type distribution data (Figure 4) combined with a visual assessment of the bulk assemblage data showed some distinct ecological segregation related to the physical oceanography of the Arabian Sea.

Bottom Line: Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses.We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed.Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biology, University of Nottingham, Nottingham, UK.

ABSTRACT

Background: Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses.

Results: We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations.

Conclusions: We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

Show MeSH