Deep-water dispersal of the tropical alga Caulerpa taxifolia introduced into the Mediterranean

Belsher, Thomas; Meinesz, A.

doi:10.1016/0304-3770(95)00469-g

Cited by 37 publications

(27 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With regard to the spread of Caulerpa taxifolia in the Mediterranean, we conclude that the estimation of the strong establishment ability of fragments (this study), in combination with results obtained by Belsher & Meinesz (1995) and Sant et al (1996), which suggest the presence of drifting fragments even in deep sltes and resistance to desiccation, respectively, indicates that the horizontal and vertical dispersal of C, taxifolia meadows by fragmentation and the establishment of new colonies is possible. Although fragmentation by human activity of existing colonies of C. taxifolia could be avoided, by preventing anchoring and fishery activities, dispersal by fragmentation due to natural disturbance could still contribute to a very wide spread of the alga in the Mediterranean.…”

Section: B: Lomdepthsupporting

confidence: 75%

See 1 more Smart Citation

The role of vegetative fragmentation in dispersal of the invasive alga Caulerpa taxifolia in the Mediterranean

Ceccherelli¹,

Cinelli²

1999

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Thls study evaluated the Importance of fragmentation in the recruitment of the fast-spreading, introduced green alga CauJerpa taxifolia at the margins of beds of the seagrass Posidonla oceam'ca. A multifactonal experiment was designed to test the hypotheses that there are seasonal differences in patterns of establishment of vegetative fragments, whether this process changes with depth and whether these patterns were consistent at different spatial and temporal scales. Our experimental approach consisted of dispersing drifting fragments of C. taxjfolja along the margin of a bed of P. oceanica and recordng the number of fragments established after 1 mo. The results show that a surprisingly large number of fragments become established in thls habitat and that numbers varied In space and time: the probability of establishment of fragments was greatest during summer especially at the shallow sites, but smaller in spring and smallest in winter. Differences among areas were also found: a great variability in establishment of fragments depended on the site and time within season. Results indicate that dispersal by fragmentation can greatly contribute to a very wide spread of the alga in the Mediterranean. We predict that spread wdl be greatest during summer when a large proportion of fragments can re-attach to the substratum, even at shallow sites. Such information is important for the understanding of the ecology of this species and, with the help of hydrographic studies, in the prediction of its patterns of geographic dispersal.

show abstract

Section: B: Lomdepthsupporting

confidence: 75%

“…Observations from a submarine by Belsher & Meinesz (1995) indicated that the alga was present either as drifting fragments or as fixed plants at depths of 45 to 100 m off the most densely invaded coast near Monaco. These authors suggested that the local downward dispersal of the tropical alga could be attributed to the detachment of fragments.…”

mentioning

confidence: 99%

The role of vegetative fragmentation in dispersal of the invasive alga Caulerpa taxifolia in the Mediterranean

Ceccherelli¹,

Cinelli²

1999

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…That is, a smaller lamp needed to be fitted, which could deliver a maximum of 75 mol m Ϫ2 s Ϫ1 when arranged to provide even illumination over the experimental subjects. Although 75 mol m Ϫ2 s Ϫ1 is generally less than samples receive at a depth of 10 m, it is closer to the average irradiance received by the species over its depth range in the northern Mediterranean (near surface to 99 m; see Belsher and Meinesz 1995).…”

Section: Methodsmentioning

confidence: 67%

“…All samples were gathered at a depth of 10 m by hand to minimize disturbance to the alga's rhizosphere. At each site, approximately equal volumes of sediment (3,000-4,000 cm 3 ) and associated C. taxifolia tissue were collected from three locations, separated by distances of at least 5 m to avoid sampling sediments linked by the same algal stolons (maximum stolon length ϭ 2.8 m; see Meinesz et al 1995). Uncolonized sediments were sampled in the same manner.…”

Section: Methodsmentioning

confidence: 99%

Stimulation of nitrogen fixation in refractory organic sediments by Caulerpa taxifolia(Chlorophyta)

Chisholm

Moulin

2003

Limnology & Oceanography

View full text Add to dashboard Cite

Estimates of N 2 fixation by substrata associated with the rhizophytic alga Caulerpa taxifolia were obtained using the acetylene reduction method. On average, growth of C. taxifolia enhanced rates of acetylene reduction in underlying dead sea grass sediments by a factor of 28, although the degree of enhancement was variable. The average rate of ethylene production was 3.96 nmol cm Ϫ3 h Ϫ1 (range ϭ 2.5-6.2 nmol cm Ϫ3 h Ϫ1 ). There was no apparent stimulation of N 2 fixation in substrata collected close to a wastewater outlet. C. taxifolia appears to enhance N 2 fixation by releasing photosynthetic product into the rhizosphere, mimicking the behavior of saltwater vascular plants. The excreted organic C activates the fermenting bacterial community, which in turn makes substrates available to the sulfate reducers. The associated microbial reactions create strong reducing conditions that favor N 2 fixation, of which many sulfate reducers are capable. Nitrogen fixation can serve to reduce the N deficit that inhibits bacterial decomposition of refractory sea grass waste, thereby enhancing organic matter turnover and nutrient supply to the alga's rhizoids. This process likely assists C. taxifolia to proliferate upon refractory organic sediments in low-nutrient seawater.The green alga Caulerpa produces a pseudo-root system that functions to anchor the plant, as well as to take up nutrients (Williams 1984; Chisholm et al. 1996). Nutrient uptake from the substratum potentially enables the alga to proliferate in oligotrophic seawater on eutrophicated substrata (Chisholm et al. 1996). Biogeochemical studies in the northwest Mediterranean have indicated a link between the proliferation of Caulerpa taxifolia Vahl. C. (Agardh) and the availability of nutrients discharged in urban wastewater or resulting from the decay of sea grass vegetation (Chisholm et al. 1997). Association with wastewater pollution is not surprising because algal production has often been shown to increase with nutrient discharge. Association with decomposition of sea grass vegetation is less straightforward because sea grass tissues generally have low N content relative to C, which limits bacterial nutrient turnover (Goldman et al. 1987;Paerl 1990).Field and laboratory observations demonstrate that sediments containing dead sea grass matter frequently turn black in color after penetration by the rhizoids of C. taxifolia (Fig. 1). The black coloration is due to bacterial reduction of sulfate to sulfide, indicating strong reducing conditions that favor N 2 fixation. Nitrogen fixation could alleviate barriers to organic decomposition (Paerl 1990;Tibbles et al. 1994), thus enhancing nutrient supply to the alga's rhizoids. C. taxifolia 1 To whom correspondence should be addressed. Present address: 149 Eyre Street, North Ward, Queensland 4810, Australia (j.chisholm@libertysurf.fr). AcknowledgmentsWe thank D. Lerudulier for use of the gas chromatograph at the University of Nice-Sophia Antipolis and J.-C. Trinchant for help with the analytical measurement...

show abstract

“…Indeed, C. taxifolia is able to acquire inorganic phosphorus and the amino acid valine from the sediment through its rhizoids (Chisholm et al 1996). Additionally, C. taxifolia photosynthesis did not meet respiratory demand below 24-29 m depth , which is not consistent with the presence of this species at depths up to 99 m (Belsher and Meinesz 1995), and leads to the suggestion that C. taxifolia is able to meet part of its carbon demand through the assimilation of external organic carbon .…”

Section: Introductionmentioning

confidence: 94%

Is the vegetative development of the invasive chlorophycean, Caulerpa taxifolia, favored in sediments with a high content of organic matter?

Terrados

Marbà

2006

Botanica Marina

View full text Add to dashboard Cite

We performed an in situ experiment raising the concentration of organic matter in sediment relative to the natural concentration, and quantified biomass development of the invasive alga, Caulerpa taxifolia, and native C. prolifera. Our objective was to determine whether vegetative development of C. taxifolia is favored in sediments with a high content of organic matter. The number of stolon apices and fronds, and the total dry weight of C. taxifolia at the end of the experiment increased relative to initial values in the ''natural'' sediment, while those in the ''organic matter-enriched'' sediment did not change. As a result, the vegetative development of C. taxifolia in the ''organic matter-enriched'' sediment was marginally lower than that in the sediment with natural concentration of organic matter. The contention that the vegetative development of the invasive C. taxifolia is favored in sediments with a high content of organic matter is not sustained. Additionally, we wanted to evaluate whether the presence of an external source of dissolved organic carbon (DOC) would facilitate the survival of Caulerpa taxifolia and C. prolifera under conditions unfavorable for biomass development. To this end we performed two laboratory experiments (one under light-saturated and another under light-limited conditions) where we maintained fragments of C. taxifolia and C. prolifera in the presence of different low molecular weight DOC compounds and assessed the survival of the two species. Mortality of Caulerpa fragments occurred under light-limited conditions only and showed no relationship to the presence of any of the low molecular weight DOC compounds tested. Our results, therefore, do not provide support for the contention that the presence of low molecular weight DOC compounds could contribute to alleviating negative effects associated with light-limited conditions.

show abstract

Deep-water dispersal of the tropical alga Caulerpa taxifolia introduced into the Mediterranean

Cited by 37 publications

References 2 publications

The role of vegetative fragmentation in dispersal of the invasive alga Caulerpa taxifolia in the Mediterranean

The role of vegetative fragmentation in dispersal of the invasive alga Caulerpa taxifolia in the Mediterranean

Stimulation of nitrogen fixation in refractory organic sediments by Caulerpa taxifolia(Chlorophyta)

Is the vegetative development of the invasive chlorophycean, Caulerpa taxifolia, favored in sediments with a high content of organic matter?

Contact Info

Product

Resources

About