ORCID Profile
0000-0002-1912-5538
Current Organisation
Linköping University
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Publisher: Informa UK Limited
Date: 2013
DOI: 10.2216/11-116.1
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.YMPEV.2008.12.018
Abstract: The siphonous green algae are an assemblage of seaweeds that consist of a single giant cell. They comprise two sister orders, the Bryopsidales and Dasycladales. We infer the phylogenetic relationships among the siphonous green algae based on a five-locus data matrix and analyze temporal aspects of their ersification using relaxed molecular clock methods calibrated with the fossil record. The multi-locus approach resolves much of the previous phylogenetic uncertainty, but the radiation of families belonging to the core Halimedineae remains unresolved. In the Bryopsidales, three main clades were inferred, two of which correspond to previously described suborders (Bryopsidineae and Halimedineae) and a third lineage that contains only the limestone-boring genus Ostreobium. Relaxed molecular clock models indicate a Neoproterozoic origin of the siphonous green algae and a Paleozoic ersification of the orders into their families. The inferred node ages are used to resolve conflicting hypotheses about species ages in the tropical marine alga Halimeda.
Publisher: Frontiers Media SA
Date: 04-03-2021
DOI: 10.3389/FCLIM.2021.638805
Abstract: Since the adoption of the Paris Agreement in 2015, spurred by the 2018 IPCC Special Report on Global Warming of 1.5°C, net zero emission targets have emerged as a new organizing principle of climate policy. In this context, climate policymakers and stakeholders have been shifting their attention to carbon dioxide removal (CDR) as an inevitable component of net zero targets. The importance of CDR would increase further if countries and other entities set net-negative emissions targets. The scientific literature on CDR governance and policy is still rather scarce, with empirical case studies and comparisons largely missing. Based on an analytical framework that draws on the multi-level perspective of sociotechnical transitions as well as existing work on CDR governance, we gathered and assessed empirical material until early 2021 from 9 Organization for Economic Co-operation and Development (OECD) cases: the European Union and three of its Member States (Ireland, Germany, and Sweden), Norway, the United Kingdom, Australia, New Zealand, and the United States. Based on a synthesis of differences and commonalities, we propose a tripartite conceptual typology of the varieties of CDR policymaking: (1) incremental modification of existing national policy mixes, (2) early integration of CDR policy that treats emission reductions and removals as fungible, and (3) proactive CDR policy entrepreneurship with support for niche development. Although these types do not necessarily cover all dimensions relevant for CDR policy and are based on a limited set of cases, the conceptual typology might spur future comparative work as well as more fine-grained case-studies on established and emerging CDR policies.
Publisher: Wiley
Date: 09-10-2014
DOI: 10.1111/JPY.12231
Abstract: The siphonous green algal family Caulerpaceae includes the monotypic genus Caulerpella and the species-rich genus Caulerpa. A molecular phylogeny was inferred from chloroplast tufA and rbcL DNA sequences analyzed together with a five marker dataset of non-caulerpacean siphonous green algae. Six Caulerpaceae lineages were revealed, but relationships between them remained largely unresolved. A Caulerpella clade representing multiple cryptic species was nested within the genus Caulerpa. Therefore, that genus is subsumed and Caulerpa ambigua Okamura is reinstated. Caulerpa subgenus status is proposed for the six lineages substantiated by morphological characters, viz., three monotypic subgenera Cliftonii, Hedleyi, and Caulerpella, subgenus Araucarioideae exhibiting stolons covered with scale-like appendages, subgenus Charoideae characterized by a verticillate branching mode, and subgenus Caulerpa for a clade regarded as the Caulerpa core clade. The latter subgenus is sub ided in two sections, i.e., Sedoideae for species with pyrenoids and a species-rich section Caulerpa. A single section with the same name is proposed for each of the other five subgenera. In addition, species status is proposed for Caulerpa filicoides var. andamanensis (W.R. Taylor). All Caulerpa species without sequence data were examined (or data were taken from species descriptions) and classified in the new classification scheme. A temporal framework of Caulerpa ersification is provided by calibrating the phylogeny in geological time. The chronogram suggests that Caulerpa ersified into subgenera and sections after the Triassic-Jurassic mass extinction and that infra-section species radiation happened after the Cretaceous-Tertiary mass extinction.
Publisher: Wiley
Date: 06-2009
DOI: 10.1111/J.1529-8817.2009.00690.X
Abstract: The genus Pseudochlorodesmis (Bryopsidales) is composed of diminutive siphons of extreme morphological simplicity. The discovery of Pseudochlorodesmis-like juveniles in more complex Bryopsidales (e.g., the Halimeda microthallus stage) jeopardized the recognition of this genus. Confronted with this uncertainty, taxonomists transferred many simple siphons into a new genus, Siphonogramen. In this study, we used a multimarker approach to clarify the phylogenetic and taxonomic affinities of the Pseudochlorodesmis-Siphonogramen (PS) complex within the more morphologically complex bryopsidalean taxa. Our analyses reveal a new layer of ersity largely distinct from the lineages containing the structurally complex genera. The PS complex shows profound cryptic ersity exceeding the family level. We discuss a potential link between thallus complexity and the prevalence and profundity of cryptic ersity. For taxonomic simplicity and as a first step toward clarifying the taxonomy of these simple siphons, we propose to maintain Pseudochlorodesmis as a form genus and subsume Siphonogramen and Botryodesmis therein.
Publisher: Wiley
Date: 09-11-2017
DOI: 10.1111/JPY.12593
Abstract: The tropical alga previously recognized as Gibsmithia hawaiiensis (Dumontiaceae, Rhodophyta) was recently suggested to represent a complex of species distributed throughout the Indo-Pacific Ocean and characterized by a peculiar combination of hairy (pilose) gelatinous lobes growing on cartilaginous stalks. Phylogenetic reconstructions based on three genetic markers are presented here with the inclusion of new s les. Further ersity is reported within the complex, with nine lineages spread in four major phylogenetic groups. The threshold between intra- and interspecific relationships was assessed by species delimitation methods, which indicate the existence of 8-10 putative species in the complex. Two species belonging to the G. hawaiiensis complex are described here: Gibsmithia malayensis sp. nov. from the Coral Triangle and Gibsmithia indopacifica sp. nov., widely distributed in the Central and Eastern Indo-Pacific. Morphological differences in the vegetative and reproductive structures of the newly described species are provided and compared to the previously described species of the complex. Additional lineages represent putative species, which await further investigation to clarify their taxonomic status. Gibsmithia hawaiiensis sensu stricto is confirmed to be endemic to the Hawaiian Islands, and Gibsmithia eilatensis is apparently confined to the Red Sea, with an expanded distribution in the region. New records of the G. hawaiiensis complex are reported from Egypt, Saudi Arabia, Indonesia, Philippines, and the Federated States of Micronesia, indicating that the complex is more broadly distributed than previously considered. The isolated position of Gibsmithia within the Dumontiaceae is corroborated by molecular data.
Publisher: Routledge
Date: 03-06-2013
No related grants have been discovered for Mathias Fridahl.