| dc.contributor.advisor | Bluhm, Bodil | |
| dc.contributor.author | Matsson, Sanna | |
| dc.date.accessioned | 2021-02-05T09:41:57Z | |
| dc.date.available | 2021-02-05T09:41:57Z | |
| dc.date.issued | 2021-03-04 | |
| dc.description.abstract | The motivation for macroalgal cultivation is to meet the global demand for food, energy and biomaterials for a rapidly growing human population in the context of the challenges of limited terrestrial food resources. Over the last 20 years the interest in seaweed cultivation has increased in European countries, and the kelp <i>Saccharina latissima</i> is one of the best-suited species for cultivation in North Atlantic waters. Epibiosis on cultivated seaweed in mid and high latitudes usually occurs from spring to summer, forcing the farmers to harvest the seaweed biomass before it reaches its potential maximum and higher carbohydrate content. Therefore, epibiosis is considered one of the main challenges in industrial seaweed farming. There has been a lack of knowledge about timing and species fouling cultivated <i>S. latissima</i> under different environmental conditions, including different latitudes, seasons and depths, as well as sporophyte age and nutritional history. This topic was investigated through three in situ studies, one with a large latitudinal range covering eleven degrees in latitude, one smaller-scale study within a geographical region characterized by differing environmental characteristics, and one with different outplanting dates resulting in various sporophyte ages within the same location at a given calendar date. The papers that this thesis is built upon show that there is spatial variability in phenology, degree and density of epibiosis on multiple scales on cultivated <i>S. latissima</i>. The present study has increased our knowledge about one of the bottlenecks for seaweed cultivation; epibiosis. Furthermore, this new fundamental understanding of timing and species diversity of epibiosis on cultivated <i>S. latissima</i> contributes to an overall understanding of the fouling issue along the Norwegian coast, enabling a broader view with important implications for the seaweed industry. | en_US |
| dc.description.doctoraltype | ph.d. | en_US |
| dc.description.popularabstract | The motivation for macroalgal cultivation is to meet the global demand for food, energy and biomaterials for a rapidly growing human population in the context of the challenges of limited terrestrial food resources. Over the last 20 years the interest in seaweed cultivation has increased in European countries, and the kelp Saccharina latissima is one of the best-suited species for cultivation in North Atlantic waters. Norway, with its extensive coastline and marine knowledge and history, has a great potential to develop this nascent industry in Europe. Seaweeds also provide a substratum for a wide array of benthic organisms for colonization, as well as food supply and permanent or temporary shelter. These organisms are called epibionts, i.e. organisms living on the surface of another organism. From an industrial perspective, epibiosis is negative, as the goal of seaweed farming is to obtain high yield of high quality biomass. As such, epibiosis in this sense is also called biofouling. Epibiosis results in seaweed biomass being less attractive for human consumption, affecting the commercial value of the yield. Epibiosis on cultivated seaweed in mid and high latitudes usually occurs from spring to summer, forcing the farmers to harvest the seaweed biomass before it reaches its potential maximum and higher carbohydrate content. Therefore, epibiosis is considered one of the main challenges in industrial seaweed farming.
There has been a lack of knowledge about timing and species fouling cultivated S. latissima under different environmental conditions, including different latitudes, seasons and depths, as well as sporophyte age and nutritional history. This topic was investigated through three in situ studies, one with a large latitudinal range covering eleven degrees in latitude, one smaller-scale study within a geographical region characterized by differing environmental characteristics, and one with different outplanting dates resulting in various sporophyte ages within the same location at a given calendar date. The papers that this thesis is built upon show that there is spatial variability in phenology, degree and density of epibiosis on multiple scales on cultivated S. latissima.
The large-scale latitudinal study revealed a south to north gradient in the onset of epibiosis, with visible epibionts appearing ~2 months later at the northernmost location, with associated implications for the harvesting period. The study within one geographical region revealed strong differences in the amount and type of epibionts among sites within a relatively short distance from one another. Temperature had the highest impact on the amount of epibiosis of the environmental parameters observed. Further, weaker currents, increased light, and most likely lower salinity were associated with lower amount of epibiosis. Combined, these results show the possibilities for a temporally shifting harvesting approach with later harvesting towards the northern Norwegian coast. Due to the large local variations shown, however, pilot investigations should be undertaken when considering a new farm location in order to acquire knowledge about the species fouling a particular location and their temporal variation.
The epibiont community had an overarching seasonal pattern in density or cover and composition in all studies. An initial onset of a few organisms was followed by a period of slowly increasing cover and density with time, and a sharp increase later in the season. The succession of fouling species began with filamentous algae and diatoms fouling the tips of the fronds. The bryozoan Membranipora membranacea was the most prevalent fouling species in all three studies of this thesis, with an increasing relative contribution over time. There was a trend for larval settlement on the meristematic regions, which eventually resulted in larger colonies and more area fouled at the seaweed tips.
Besides choice of location, environmental history and/or age of the seaweed host may affect the epibiosis. S. latissima outplanted later in the season had no difference in concentration of nitrogen compounds, but had a higher content of carbon and a lower density of fouling organisms. One of the reasons for this result was both a higher growth and shedding of seaweed fronds in this treatment.
The present study has increased our knowledge about one of the bottlenecks for seaweed cultivation; epibiosis. Furthermore, this new fundamental understanding of timing and species diversity of epibiosis on cultivated S. latissima contributes to an overall understanding of the fouling issue along the Norwegian coast, enabling a broader view with important implications for the seaweed industry. | en_US |
| dc.description.sponsorship | project number 254883, MACROSEA, Norges forskningsråd
Troms County (RDA 12/234 "Pilotstudie på bioenergi fra tare", | en_US |
| dc.identifier.isbn | 978-82-8266-192-8 | |
| dc.identifier.uri | https://hdl.handle.net/10037/20519 | |
| dc.language.iso | eng | en_US |
| dc.publisher | UiT The Arctic University of Norway | en_US |
| dc.publisher | UiT Norges arktiske universitet | en_US |
| dc.relation.haspart | <p>Paper I: Matsson, S., Fieler, R. & Christie, H. (2019). Variation in biomass and biofouling of kelp, <i>Saccharina latissima</i>, cultivated in the Arctic, Norway. <i>Journal of Aquaculture, 506</i>, 445-452. Also available at <a href=https://doi.org/10.1016/j.aquaculture.2019.03.068> https://doi.org/10.1016/j.aquaculture.2019.03.068</a>.
<p>Paper II: Forbord, S., Matsson, S., Brodahl, G.E., Bluhm, B.A., Broch, O.J., Handå, A., … Olsen, Y. (2020). Latitudinal, seasonal and depth-dependent variation in growth, chemical composition and biofouling of cultivated <i>Saccharina latissima</i> (Phaeophyceae) along the Norwegian coast. <i>Journal of Applied Phycology, 32</i>, 2215-2232. Also available in Munin at <a href=https://hdl.handle.net/10037/17221>https://hdl.handle.net/10037/17221</a>.
<p>Paper III: Matsson, S., Metaxas, A., Forbord, S., Kristiansen, S., Handå, A. & Bluhm, B.A. Effects of outplanting time on growth, shedding and quality of <i>Saccharina latissima</i> (Phaeophyceae). (Submitted manuscript). | en_US |
| dc.relation.projectID | info:eu-repo/grantAgreement/RCN/HAVBRUK2/254883/Norway/MACROSEA - A knowledge platform for industrial macroalgae cultivation/MACROSEA/ | en_US |
| dc.rights.accessRights | openAccess | en_US |
| dc.rights.holder | Copyright 2021 The Author(s) | |
| dc.subject.courseID | DOKTOR-002 | |
| dc.subject | Aquaculture | en_US |
| dc.subject | Phycology | en_US |
| dc.subject | VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 | en_US |
| dc.subject | VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 | en_US |
| dc.title | Fouling of macro epibionts on cultivated Saccharina latissima (Phaeophyceae). In situ temporal and spatial variation | en_US |
| dc.type | Doctoral thesis | en_US |
| dc.type | Doktorgradsavhandling | en_US |
English
norsk