The clonal seaweed Chondrus crispus as a foundation species

Scrosati, Ricardo A. The Korean Society of Phycology 2016 ALGAE Vol.31 No.1

The clonal seaweed Chondrus crispus (Rhodophyta, Gigartinales) forms extensive stands at low intertidal elevations on wave-sheltered rocky shores of the North Atlantic. This study investigates if this bushy alga acts as a foundation species in such habitats. The abundance (percent cover) of C. crispus, all other algae, and invertebrates was measured in 390 quadrats spanning 350 km of coast in Nova Scotia, Canada. In these low-intertidal habitats, fucoid algae are the largest organisms and can form extensive canopies, but their cover was unrelated to benthic species richness and to C. crispus cover. Species richness, however, increased with C. crispus cover from low to intermediate cover values, showing little change towards full C. crispus cover. Species composition (a combined measure of species identity and their relative abundance) differed between quadrats with low (0-1%) and high (60-100%) cover of C. crispus. High C. crispus cover was associated to more invertebrate species but fewer algal species than low C. crispus cover. However, the average abundance of algal and invertebrate species occurring in both cover groups was often higher under high C. crispus cover, contributing to a higher average richness at the quadrat scale. Overall, only 16% of the observed variation in species richness was explained by C. crispus cover. Therefore, this study suggests that C. crispus acts as a foundation species but with a moderate influence.

Community-level facilitation by macroalgal foundation species peaks at an intermediate level of environmental stress

Scrosati, Ricardo A. The Korean Society of Phycology 2017 ALGAE Vol.32 No.1

In rocky intertidal habitats, abiotic stress due to desiccation and thermal extremes increases with elevation because of tides. A study in Atlantic Canada showed that, at low elevations where conditions are benign due to the brief low tides, fucoid algal canopies (Ascophyllum nodosum and Fucus spp.) do not affect the structure of benthic communities. However, at middle and high elevations, where low tides last longer, fucoid canopies limit abiotic extremes and increase the richness (number of invertebrate and algal species, except fucoids) of benthic communities. Using the data from that study, this paper compares the intensity of facilitation and its importance (relative to all other sources of variation in richness) between middle and high elevations, which represent intermediate and high stress, respectively. Facilitation intensity was calculated as the percent increase in benthic richness between quadrats with low and high canopy cover, while the importance of facilitation was calculated as the percentage of variation in richness explained by canopy cover. Data for 689 quadrats spanning 350 km of coastline were used. Both the intensity and importance of facilitation were greater at middle elevations than at high elevations. As canopies do not affect benthic communities at low elevations, this study suggests that the facilitation-stress relationship at the community level is unimodal for this marine system. Such a pattern was found for some terrestrial systems dominated by canopy-forming plants. Thus, it might be ubiquitous in nature and, as further studies refine it, it might help to predict community-level facilitation depending on environmental stress.

Status: Prospect and Future

( Bruno Scrosati ) 한국공업화학회 2009 한국공업화학회 연구논문 초록집 Vol.2009 No.1

The clonal seaweed Chondrus crispus as a foundation species

Ricardo A. Scrosati 한국조류학회I 2016 ALGAE Vol.31 No.1

The clonal seaweed Chondrus crispus (Rhodophyta, Gigartinales) forms extensive stands at low intertidal elevations on wave-sheltered rocky shores of the North Atlantic. This study investigates if this bushy alga acts as a foundation species in such habitats. The abundance (percent cover) of C. crispus, all other algae, and invertebrates was measured in 390 quadrats spanning 350 km of coast in Nova Scotia, Canada. In these low-intertidal habitats, fucoid algae are the largest organisms and can form extensive canopies, but their cover was unrelated to benthic species richness and to C. crispus cover. Species richness, however, increased with C. crispus cover from low to intermediate cover values, showing little change towards full C. crispus cover. Species composition (a combined measure of species identity and their relative abundance) differed between quadrats with low (0–1%) and high (60–100%) cover of C. crispus. High C. crispus cover was associated to more invertebrate species but fewer algal species than low C. crispus cover. However, the average abundance of algal and invertebrate species occurring in both cover groups was often higher under high C. crispus cover, contributing to a higher average richness at the quadrat scale. Overall, only 16% of the observed variation in species richness was explained by C. crispus cover. Therefore, this study suggests that C. crispus acts as a foundation species but with a moderate influence.

Community-level facilitation by macroalgal foundation species peaks at an intermediate level of environmental stress

Ricardo A. Scrosati 한국조류학회I 2017 ALGAE Vol.32 No.1

In rocky intertidal habitats, abiotic stress due to desiccation and thermal extremes increases with elevation because of tides. A study in Atlantic Canada showed that, at low elevations where conditions are benign due to the brief low tides, fucoid algal canopies (Ascophyllum nodosum and Fucus spp.) do not affect the structure of benthic communities. However, at middle and high elevations, where low tides last longer, fucoid canopies limit abiotic extremes and increase the richness (number of invertebrate and algal species, except fucoids) of benthic communities. Using the data from that study, this paper compares the intensity of facilitation and its importance (relative to all other sources of variation in richness) between middle and high elevations, which represent intermediate and high stress, respectively. Facilitation intensity was calculated as the percent increase in benthic richness between quadrats with low and high canopy cover, while the importance of facilitation was calculated as the percentage of variation in richness explained by canopy cover. Data for 689 quadrats spanning 350 km of coastline were used. Both the intensity and importance of facilitation were greater at middle elevations than at high elevations. As canopies do not affect benthic communities at low elevations, this study suggests that the facilitation-stress relationship at the community level is unimodal for this marine system. Such a pattern was found for some terrestrial systems dominated by canopy-forming plants. Thus, it might be ubiquitous in nature and, as further studies refine it, it might help to predict community-level facilitation depending on environmental stress.

Batteries: The Role of AlF₃ Coatings in Improving Electrochemical Cycling of Li‐Enriched Nickel‐Manganese Oxide Electrodes for Li‐Ion Batteries (Adv. Mater. 9/2012)

Sun, Yang‐,Kook,Lee, Min‐,Joon,Yoon, Chong S.,Hassoun, Jusef,Amine, Khalil,Scrosati, Bruno WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.9

<P>Y.‐K. Sun, C. S. Yoon, B. Scrosati and co‐workers report on page 1192 the role of an AlF3‐coating layer on Li‐enriched cathode materials, which not only improves electrochemical performances but also thermal stability. These improvements are attributed to the trans‐formation of the initial layer (Li<SUB>2</SUB>MnO<SUB>3</SUB>) to a spinel phase, induced by the Li chemical‐leaching effect of the AlF3 coating layer. The spinel phase transferred from the layer on the Li‐enriched electrodes is able to negate the previous shortcomings of these designs. </P>

Lithium‐Sulfur Batteries: An Advanced Lithium‐Sulfur Battery (Adv. Funct. Mater. 8/2013)

Kim, Junghoon,Lee, Dong‐,Ju,Jung, Hun‐,Gi,Sun, Yang‐,Kook,Hassoun, Jusef,Scrosati, Bruno WILEY‐VCH Verlag 2013 Advanced functional materials Vol.23 No.8

<P>On page 1076, Yang‐Kook Sun, Jusef Hassoun, Bruno Scrosati, and co‐workers report and characterize a hard carbon spherules‐sulfur electrode that is prepared by impregnation of crystalline sulfur into the carbon spheres through melting and thermal treatment. This material demonstrates very high capacity and rate capability, and is therefore proposed as a new generation cathode to drive electric vehicles over a long range. </P>

Stable, High Voltage Li_0.85Ni_0.46Cu_0.1Mn_1.49O₄ Spinel Cathode in a Lithium-Ion Battery Using a Conversion-Type CuO Anode

Verrelli, Roberta,Scrosati, Bruno,Sun, Yang-Kook,Hassoun, Jusef American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.7

<P>We report in this work a copper-doped Li<SUB>0.85</SUB>Ni<SUB>0.46</SUB>Cu<SUB>0.1</SUB>Mn<SUB>1.49</SUB>O<SUB>4</SUB> spinel-structured compound prepared by an easy, two-steps coprecipitation and solid state process and used in a lithium-ion battery in combination with a CuO-based anode. We show that the spinel-type cathode adopts unique morphology, characterized by well-developed, crystalline and aggregated microparticles, that considerably reduces the occurrence of side reactions. This cathode material can operate in a lithium cell at voltages as high as 5.3 V without sign of electrolyte decomposition, delivering a capacity of about 100 mA h g<SUP>–1</SUP> with high retention and high Coulombic efficiency over prolonged cycling. The combination of the Li<SUB>0.85</SUB>Ni<SUB>0.46</SUB>Cu<SUB>0.1</SUB>Mn<SUB>1.49</SUB>O<SUB>4</SUB> cathode with a conversion-type, CuO–MCMB anode results in a new type of lithium ion battery characterized by a voltage value of 3.4 V, a stable capacity of 100 mA h g<SUP>–1</SUP> and a high Coulombic efficiency (exceeding 95%). Expected low cost, safety, and environmental compatibility are additional advantages of the lithium-ion cell reported here.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-7/am500499a/production/images/medium/am-2014-00499a_0008.gif'></P>

Mixed Electrolytes of Organic Solvents and Ionic Liquid for Rechargeable Lithium-Ion Batteries

Choi, Ji-Ae,Shim, Eun-Gi,Scrosati, Bruno,Kim, Dong-Won Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.11

Mixed electrolytes formed by the combination of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP-TFSI) ionic liquid and standard liquid electrolyte are prepared and characterized. Linear sweep voltammetry measurements demonstrate that these mixed systems exhibit a wide electrochemical stability window, allowing them to be suitable electrolyte for carbonaceous anode-based lithium-ion batteries. Lithium-ion cells composed of graphite anode and $LiCoO_2$ cathode are assembled using the mixed electrolytes, and their cycling performances are evaluated. The cell containing proper content of BMP-TFSI shows good cycling performance comparable to that of a cell assembled with organic electrolyte. The presence of BMP-TFSI in the mixed electrolyte contributes to the reduction of the flammability of electrolyte solution and the improvement of the thermal stability of charged $Li_{1-x}CoO_2$ in the electrolyte solution.

Microscale Mo-doped C-LiFePO4 with high tap density as positive electrode materials for lithium batteries

Yang-Kook Sun,Seung-Min Oh,Bruno Scrosati 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5