Marine Macroalgae: Prospective Hitchhikers of Ship Ballast

Invasive alien species, on successful establishment, can displace native species. The threat of invasive species arises in view of their ability to outcompete and destabilize native biodiversity. Invasive species are found across all taxonomic groups of plants, animals and microorganisms. The green macroalga Ulva flexuosa has a potential to become invasive and this species was investigated for its hitchhiking potential under laboratory conditions. Zoospores of U. flexuosa were maintained at 4°C for nearly 10 months in the dark. Recruitment potential of zoospores after dark stress was tested in a modified Provasoli medium under optimal laboratory conditions. The success rate of zoospore recruitment was 61%. The paper describes the transfer potential through shipping activities by correlating the Ulva zoospores recruitment potential and survivability

Time course nutrient uptake study of some intertidal rocky shore macroalgae and the limiting effect due to synergistic interaction

287-292The time course nutrient uptake study of some intertidal rocky shore macroalgae showed a marked variation in the uptake of nutrients. In the present study, Caulerpa sertularioides, Padina tetrastomatica, Sargassum cinctum, andGracilaria corticata which are slow growingassimilated ammonium, whereas the fast growing Chaetomorpha antennina, Ulva flexuosa, and Ulva lactuca assimilated nitrate. Nitrate in the medium was assimilated quickly by these three species. It was below the detection level after five hours. The study showed that the characteristic of nutrient uptake varies between different macroalgae. The slow growing perennial macroalgae preferred ammonium and fast growing annuals preferred nitrate.The preference of different form of nitrogen is inferred to be mainly due to low energetic cost and opportunistic uptake. The combination of nutrient-N and phosphate in the medium showed a synergistic interactive effect in some of the algae wherein the uptake of nutrient was slowed comparatively. This synergistic interactive effect was significant (P Caulerpa sertularioides, Chaetomorpha antennina,and Ulva lactuca

Recruitment Potential of a Green Alga Ulva flexuosa Wulfen Dark Preserved Zoospore and Its Development

The recruitment potential and the ability of Ulva flexuosa Wulfen zoospores to survive darkness were tested under different conditions in the present study. The dark preserved zoospore was cultured under a two-factor experimental design to test the effect of salinity and nitrate, effect of salinity and phosphate, effect of light and salinity, and effect of light and phosphate. The recruitment (germination and growth) of zoospores was significantly affected by light and salinity. The nitrate concentration of 20 µmol.l−1 was found to initiate the process of germination and its subsequent growth and, its effect appeared greatest under 25 psu condition. While nitrate enhances the growth of biomass more than phosphate, both show a positive interactive effect on biomass increase when crossed with salinity. The combined effect of 25 psu salinity and 8 µmol.l−1 phosphate exhibited higher biomass growth. There was a significant effect of light and salinity on the biomass of zoospore, though there was no significant interaction between the two factors. There was an increase in biomass of growing zoospores to increase in light intensity and 80 µmol.m−2.s−1 of light intensity was considered optimal. Similarly, high light intensity condition favored higher biomass growth and there was significant interaction between light (80 µmol. m−2. s−1) and phosphate (4 µmol. l−1) in high salinity (35 psu) condition. The result of this study showed that dark preserved zoospores of U. flexuosa have the potential for recruitment and it gives us an understanding how different factors play a role in the process of recruitment

Substrate deposit effect on the characteristic of an intertidal macroalgal community

333-338<span style="font-size:9.0pt;mso-bidi-font-size: 11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-gb;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="" lang="EN-GB">Present study consists the effect of substrate deposit (silt, clay, sand, gravel and shards of shells) on the characteristic of an intertidal rocky shore macroalgae.  Macroalgal assemblage was segregated from substrate deposit in two stages.  Substrate deposit was subsequently quantified. Silt and sand-shell combine were the major constituent of the substrate deposit.  Subsequent results showed that the characteristic of the intertidal macroalgal assemblages are influenced both positively and negatively. Species richness was high in a station with high clay substrate deposit.  Substrate deposit as a whole, thus, has a functional role and has an influencing role which can cause a characteristic change on the macroalgal diversity of intertidal rocky shore ecosystem. </span

<span style="font-size:15.0pt;mso-bidi-font-size:12.0pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language: EN-US;mso-bidi-language:HI" lang="EN-GB">Effect of temperature, salinity and biofilm on the zoospores settlement of <i style="mso-bidi-font-style:normal">Enteromorpha flexuosa </i>(Wulfen) J.Agardh</span>

355-358<span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Present study consists the, effect of temperature (10-30oC), salinity (15-35 psu) and biofilm on the settlement of Enteromorpha flexousa zoospores. Settlement of zoospores was significantly (<i style="mso-bidi-font-style: normal">p0.05) influenced by both temperature and salinity. Highest percentage of settlement occurred at 25oC and 30 psu respectively. Subsequently the influence of biofilm was evaluated at the optimum 25oC and 30 psu culture conditions. Among these, the glass cover slip substratum preconditioned with biofilm facilitated higher settlement. Highest spore settlement occurred in the first 30 minutes of incubation and further increase was gradual with time until it reached the optimum. </span

Simplified scheme of two-factorial experiment.

<p>Simplified scheme of two-factorial experiment.</p

A. Measurement of Chlorophyll a concentration for the determination of growing zoospore biomass of <i>U. flexuosa.</i>

<p>Three levels of light and phosphate with nitrate (80 µmol⁻¹) and salinity (35 psu) as constant. <b>B.</b> Mean growth rate (d-1) from interaction of different levels of light and phosphate. Bar indicates standard error ±1 (n = 4) and different letters represent significant differences between treatments.</p

A. Measurement of Chlorophyll a concentration for the determination of growing zoospore biomass of <i>U. flexuosa</i>.

<p>Three levels of salinity and nitrate with phosphate (15 µmol⁻¹) as constant. <b>B.</b> Mean growth rate (d-1) from interaction of different levels of salinities and nitrate. Bar indicates standard error ±1 (n = 4) and different letters represent significant differences between treatments.</p

A. Measurement of Chlorophyll a concentration for the determination of growing zoospore biomass of <i>U. flexuosa</i>.

<p>Three levels of salinity and phosphate with nitrate (80 µmol⁻¹) as constant. <b>B.</b> Mean growth rate (d-1) from the interaction of different levels of salinities and phosphate. Bar indicates standard error ±1 (n = 4) and different letters represent significant differences between treatments.</p

Effect of regulated stress and its potential implication in <em>Ulva fasciata</em>

34-38Salinity, desiccation, and light deficient stress were the three different stress used to examine the regulated stress effect on Ulva fasciata (Sea lettuce). The interactive effect of time and salinity was recorded in both SOD and Catalase enzyme activity. The overall percent increase of SOD activity was 40%±0.79 and 433%±83.58 in Catalase activity in 100 psu respectively after 72 h. Similarly, the cumulative effect of stress on the activity of antioxidant enzymes was significant in all the test condition. The study showed that regulated stress could enhance protein content significantly. An increase of 317% of protein content was recorded after 48 h of desiccation. The protein concentration in desiccation stress was more by 53.42% and 63.4% than dark and salinity stress. The ability to enhance biotic compound through modulated stress can be an effective way of harnessing and sustainable use of natural resources. The elevated concentration of protein and an antioxidant enzyme activity due to the regulated stress in the present study suggest this possibility. The enhancement of a biologically active compound through regulated stress can be a handy tool for biotech based industry