Modelling of pristine depth limits for macrophyte growth in the southern Baltic Sea

Domin, A.; Schubert, Hendrik; Krause, Jochen C.; Schiewer, U.

doi:10.1023/b:hydr.0000018204.47081.ae

Cited by 25 publications

(8 citation statements)

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“…These values correspond well to the lower light limits (around 40-45% SI) given for other charophytes in brackish water (Domin et al, 2004). Higher energy demand due to the necessity of turgor regulation is just one explanation for this restriction of charophytes from deeper water.…”

Section: Discussionsupporting

confidence: 84%

Elongation and mat formation of Chara aspera under different light and salinity conditions

Blindow

Schütte

2007

Hydrobiologia

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Former laboratory results indicate that shoot elongation at low light intensities of Chara aspera is absent already at 10 psu which is within the physiologically optimal salinity range for brackish water populations. To investigate if similar restrictions occur in the field, density and morphology of C. aspera were compared between three freshwater and three brackish water sites along its depth range. The lower depth limit of C. aspera varied considerably among sites (30-600 cm) related to turbidity. Light availability at the lower depth limit corresponded to about 15% of surface irradiance in freshwater and brackish water with lower salinity (3.4 psu). Total length increased and fresh weight:length ratio decreased with depth at these sites indicating shoot elongation related to lower light availability. Due to shoot elongation, light availability was far higher at the upper parts of the shoot than at the bottom in the turbid sites. Light availability at the lower depth limit was higher (about 40%) at two sites with higher salinity (7-8 psu), where no shoot elongation was observed at the lower depth limit. Instead, the plants were stunted and often covered with filamentous algae or shaded by other rooted submerged macrophytes indicating competitive disadvantages of C. aspera at higher salinities. As growth in high densities (mat formation) exposes the plants to severe self-shading, it is suggested that shoot elongation is a prerequisite to mat formation. Dense vegetation of C. aspera was found only in freshwater and brackish water with lower salinity. Single, richly branched plants occurred in clearwater sites with higher salinity. C aspera was not found in ''double stress'' environments with both high turbidity and high salinity: We asume that the species is a poor competitor under these conditions. Our results indicate that morphological differences between freshwater and brackish water populations of C. aspera are at least partly explained by salinity rather than genetic differences.

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Section: Discussionsupporting

confidence: 84%

Elongation and mat formation of Chara aspera under different light and salinity conditions

Blindow

Schütte

2007

Hydrobiologia

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“…Therefore, it could prove to be a particularly useful tool for managers as an early warning indicator for coastal habitat monitoring and conservation. Since seagrasses in the Mediterranean seem to be not light limited as is the case in the Baltic Sea (Hemminga and Duarte, 2000), where lower depth limits were used as an indicator of water quality (Domin et al, 2004;Krause-Jensen et al, 2004), CymoSkew can be used as a new classification tool for WFD purposes (Table 8). Obviously, the suggested classification scheme is provisional and needs further verification.…”

Section: Discussionmentioning

confidence: 99%

“…Knowledge of this widely distributed species, however, is very limited, escpecially in comparison with the other common Mediterranean seagrass Posidonia oceanica (Cancemi et al, 2002). Both Posidonia (Cancemi et al, 2003;Ruiz and Romero, 2003) and Cymodocea (Barbera´et al, 2005;Cunha and Duarte, 2005) meadows are declining in the Mediterranean and the Canary Isles, due to the effects of anthropogenic nutrient additions and decreasing water transparency (for review see Leoni et al, 2008), similar to what is happening to other seagrasses worldwide (Larkum et al, 1989, and the literature therein; Dennison et al, 1993;Durako, 1995;Hemminga and Duarte, 2000;Short et al, 2001;Domin et al, 2004;Krause-Jensen et al, 2004;Schaffelke et al, 2005;Burkholder et al, 2007). Opportunistic macroalgae are able to gain advantage over angiosperms in such nutrientrich and turbid conditions due to their efficient nutrient assimilation and lower light demand for growth (Lu¨ning, 1990;Dennison et al, 1993;Kenworthy and Fonseca, 1996;Schramm and Nienhuis, 1996), while the opposite happens under oligotrophic conditions, where angiosperms have an advantage over seaweeds by using nutrients from the sediment (Borum, 1996;Hemminga and Duarte, 2000).…”

Section: Introductionmentioning

confidence: 99%

Size distribution approaches for monitoring and conservation of coastal Cymodocea habitats

Orfanidis¹,

Papathanasiou²,

Gounaris³

et al. 2009

Aquatic Conservation

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ABSTRACT1. Cymodocea nodosa's leaf length distribution was studied as an easily measurable indicator to monitor and conserve Macedonian, North Aegean, Greek coastal habitats.2. Three Cymodocea meadows off the eastern Kavala Gulf coast (Nea Karvali, Erateino, Agiasma), with that of Nea Karvali close to an industrial area being the most degraded, were sampled during the seagrass main growing season in July 2004. Two further meadows, one pristine to less degraded (Brasidas, Gulf of Kavala) and one degraded (Biamyl, Inner Thessaloniki Gulf ), were sampled as benchmarks in July 2005. The results were evaluated using Gaussian fit curves, and non-parametric and nested parametric ANOVA on a hierarchy of spatial scales: area (tens of metres), site (hundreds of metres) and meadow (kilometres).3. Frequency (%) distribution of leaf length values and CymoSkew index variation were best associated with anthropogenic stress. Frequency (%) distribution of adult and intermediate photosynthetic leaf length values revealed a unimodal distribution possible to be fitted, at least at pristine to less degraded meadows, by normal distribution (R 2 40.5). 4. Statistically significant variation was estimated for CymoSkew index, a quantitative expression of leaf length asymmetry, on the meadow scale (Po0.001). Biamyl (3.82) and Nea Karvali (3.64) were indicated as heavily degraded meadows, Erateino (2.93) as a degraded meadow, Agiasma (2.18) as a meadow with the first signs of degradation, and Brasidas (1.68) as a pristine to less degraded meadow. These results in combination with other meadow specific biotic parameters were used to suggest a preliminary angiosperm 'Ecological Status Classes' classification scheme useful for the implementation of WFD in the north Aegean Sea.5. The CymoSkew index seems to respond to lower levels of stress than is needed for other more conservative plant modules and therefore, could be regarded as an early warning indicator of Cymodocea habitat degradation.

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“…They are sensitive to anthropogenic stress (Dennison et al, 1993;Duraco, 1995;Domin et al, 2004;Krause-Jensen et al, 2004), and have recently been incorporated as quality elements in water quality monitoring programmes (for US EPA see Gibson et al, 2000;for WFD see EC, 2000). Habitat includes all aspects of an organism's life history, including how a particular location meets these needs relative to substrate, water quality etc.…”

Section: Introductionmentioning

confidence: 99%

Variation of structural and functional metrics in macrophyte communities within two habitats of eastern Mediterranean coastal lagoons: natural versus human effects

Orfanidis¹,

Pinna²,

Sabetta³

et al. 2008

Aquatic Conserv: Mar. Freshw. Ecosyst.

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2. The aim was to differentiate metric variation caused by human or natural processes and thereby to (1) select reliable metrics and (2) develop user-friendly protocols for cost-effective monitoring programmes for coastal lagoon water quality.3. Eight different sites dominated by macrophyte communities characterized by two angiosperms (Ruppia cirrhosa and R. maritima), two opportunistic macroalgae (Ulva sp. and Chaetomorpha linum), and Cyanobacteria colonies were quantitatively and destructively sampled twice.4. Structural metrics showed highest heterogeneity at a local site-specific scale, while functional metrics showed highest heterogeneity at the scale of habitat. As a result the structural metrics appeared inappropriate as indicators of lagoon water quality changes. By contrast shifts of habitat dominated by angiosperms to opportunistic macroalgae owing to nutrient excess, especially nitrogen, can be identified by functional metrics, especially with EEI.

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Modelling of pristine depth limits for macrophyte growth in the southern Baltic Sea

Cited by 25 publications

References 0 publications

Elongation and mat formation of Chara aspera under different light and salinity conditions

Elongation and mat formation of Chara aspera under different light and salinity conditions

Size distribution approaches for monitoring and conservation of coastal Cymodocea habitats

Variation of structural and functional metrics in macrophyte communities within two habitats of eastern Mediterranean coastal lagoons: natural versus human effects

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