Náttúra og náttúrutilfeingi
Porphyra in the North Atlantic and the connection to the North Pacific Porphyra - diversity, distribution, ecology, morphology and phylogeny
Agnes Mols Mortensen
University of New Hampshire
01.09.2008 - 01.08.2012
Stuðul úr Granskingargrunninum:
Growing awareness related to the quality of fish fillets, including soft texture and holes in the surface (gaping), has led to financial losses to the fish and fish farming industry. It is relatively well documented that the rapid softening that follows the end of rigor mortis and gaping is to some degree related to its collagen content and the action of specific collagenase enzymes on the collagen helices contributing to an increase in its solubility. However, relating these quality problems of fish fillets to only a specific protein has proved to be too simplified. Even if many universities worldwide have invested a lot of time and money in research concerning the relationship between collagen and the quality of fish fillets, only limited effort has been made to include the effect of PGs and GAGs, which interact with collagen in the extracellular matrix (ECM) of the connective tissue in fish muscle. The primary objective of the present Ph.D. study is to investigate the content and composition of PGs and GAGs as well as the content and degradation of collagen in the connective tissue in order to determine how the interaction between PGs, GAGs and collagen in the connective tissue influence gaping and the loss of firmness of fish fillets. The goal is to produce scientific data concerning the content and degradation of the macromolecules in the connective tissue of fish muscle as well as methods that could counteract the deterioration process.
Foliose Bangiales species have a long history of study in the North Atlantic, but regions, especially in the northern parts, need more attention. Based on both new collections and herbarium material from Iceland, the Faroe Islands, West Greenland, UK, Norway, Sweden, Denmark and the Northwest Atlantic coast (from Newfoundland to Florida) the aim was to document diversity and distribution of foliose Bangiales species in the North Atlantic and to make floristic comparisons between the geographical areas. Species Identification was based on DNA sequences using the mitochondrial cox1, chloroplast rbcL and 3’ rbcL + 5’ rbcL-S markers. The North Atlantic species were analysed in a larger phylogenetic context based on rbcL sequences, with special emphasis on the relationship between the North Atlantic and North Pacific foliose Bangiales. Using the mitochondrial cox2-3 and nuclear ITS1 spacers a preliminary phylogeographic study was carried out for Wildemania amplissimathat is represented in both the North Atlantic and North Pacific.
Four foliose Bangiales genera and 26 specieswere documented from the North Atlantic, and including both recent collections and herbarium material, the work documented both present and historic foliose Bangiales species diversity and geographic distribution, and demonstrated the value of well-preserved historic collections. Eleven foliose Bangiales species were reported from Iceland and the Faroe Islands, and seven species were reported from West Greenland. The Northwest-and Northeast Atlantic foliose Bangiales floras were equally diverse but with some differences in species composition. Pyropia njordii sp. nov. was described from the Faroe Islands, with distribution records from Iceland, West Greenland, Northeast Canada and Northeast America, and Wildemania abyssicola comb. nov. was documented from from Iceland and northern Norway. Pyropia thulaeawas reported for the first time from the Northwest Atlantic coast, and Py. peggicovensisand “Py. novae-angliae”were reported for the first time in the Northeast Atlantic. A close phylogenetic relationshipwas observed between the North Atlantic and North Pacific foliose Bangiales, especially between the West Greenland flora and the North Pacific flora. The ITS1 spacer was used in resolving phylogeogaphic patterns in W. amplisima, with 16 haplotypes recovered, and a much higher haplotype diversity recovered in the North Atlantic than in the North Pacific.
The PhD work was defended and approved at the University of New Hampshire on the 12th of September 2014.
Scientific articles, books, thesis etc.
The entire work was published in the dissertation:
Mols-Mortensen, A. (2014). The foliose Bangiales (Rhodophyta) in the northern part of the North Atlantic anf the relationship with the North Pacific foliose Bangiales –diversity, distribution, phylogeny and phylogeography.
Two scientific papers based on the PhD work have so far been published, and a third paper is submitted: Mols-Mortensen, A., Neefus, C. D., Nielsen, R., Gunnarsson, K., Egilsdóttir, S., Pedersen, P. M. and Brodie, J. (2012). New insights into the biodiversity and generic relationships of foliose Bangiales (Rhodophyta) in Iceland and the Faroe Islands. European Journal of Phycology 47: 146–159.
Mols-Mortensen, A., Neefus, C. D., Pedersen, P. M. and Brodie, J. (2014). Diversity and distribution of foliose Bangiales (Rhodophyta) in West Greenland: a link between the North Atlantic and the North Pacific. European Journal of Phycology 49:1–10.
Mols-Mortensen, A., Neefus, C. D. and Brodie, J. Diversity ans distribution of foliose Bangiales (Rhodophyta) species in the Northwest Atlantic in the context of the North Atlantic. Submitted to Nova Hedwigia. Page 5 of 6 A part of the work that was carried out on the foliose Bangiales flora in West Greenland was published in the book Grønlands Havalger(Pedersen, P. M. (2011). Grønlands Havalger. Epsilon).
Publicationes outsite the scientific community, i.e. lectures, periodicals, articles in newpapers, television and radio
Appart from scientific publications the work was presented in a popular science article (Mols-Mortensen, A. (2011). Vís mær ílegurnar og eg skal siga hvør tú ert. Frøði 1), and the lectures Algae, biodiversity and genetic markers (FarGen 2012) and Tari, fjølbroytni og ílegur (Vísindavøka 2012).