Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield?
Recent interest in scaling commercial kelp industries in Western cultures is juxtaposed by the apparent challenges in achieving more consistent and predictable yields. As such, site-level factors are a dominant and recurring conversation amongst stakeholders. The availability of seawater nitrogen (n...
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MDPI AG
2024-07-01
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| author | Tiffany Stephens Yaoguang Li Charles Yarish Matthew C. Rogers Schery Umanzor |
| author_facet | Tiffany Stephens Yaoguang Li Charles Yarish Matthew C. Rogers Schery Umanzor |
| author_sort | Tiffany Stephens |
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| description | Recent interest in scaling commercial kelp industries in Western cultures is juxtaposed by the apparent challenges in achieving more consistent and predictable yields. As such, site-level factors are a dominant and recurring conversation amongst stakeholders. The availability of seawater nitrogen (nitrate, ammonium, total N) can be highly variable across space and time and is often one of the top concerns for site selection and permitting. This study questions the relative importance of nitrogen availability on the yield of <i>Saccharina latissima</i> (sugar kelp) across five commercial farms on the U.S. East and West Coasts over two seasons, highlighting the relative influence of other interacting factors (i.e., farm design). We hypothesized that nitrate would strongly correlate with the harvested yield. Our results show significant spatial and annual variability in the kelp yield and ambient nutrients across and within farms, but with weak covariance. Standard linear regression suggests that seawater nitrogen is a poor explanatory factor for kelp yield, explaining 11.0% of the variation around the mean compared to the line spacing (explaining 26.1%) and the interaction between the total N and the line spacing (explaining 50.0%). Quartile regression, however, suggests that total N alone, is the strongest predictor of a lower threshold in terms of the yield (0.10 quartile, r<sup>2</sup> = 0.431) relative to the median (0.50 quartile, r<sup>2</sup> 0.081). As such, seawater nitrogen may be a more useful metric in predicting baseline kelp yields rather than realized yields, and production above that baseline is likely more dependent on other factors that may or may not interact with seawater nitrogen. |
| format | Article |
| id | doaj-art-ad755a5bde8c4fddbb844900100c0bef |
| institution | OA Journals |
| issn | 2673-9410 |
| language | English |
| publishDate | 2024-07-01 |
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| series | Phycology |
| spelling | doaj-art-ad755a5bde8c4fddbb844900100c0bef2025-08-20T01:55:46ZengMDPI AGPhycology2673-94102024-07-014337038310.3390/phycology4030020Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield?Tiffany Stephens0Yaoguang Li1Charles Yarish2Matthew C. Rogers3Schery Umanzor4College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, AK 99801, USAAGQ Solutions, 123 Windsorville Rd, South Windsor, CT 06074, USAWoods Hole Oceanographic Institution, 86 Water St, Falmouth, MA 02543, USAAlaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Juneau, AK 99801, USACollege of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, AK 99801, USARecent interest in scaling commercial kelp industries in Western cultures is juxtaposed by the apparent challenges in achieving more consistent and predictable yields. As such, site-level factors are a dominant and recurring conversation amongst stakeholders. The availability of seawater nitrogen (nitrate, ammonium, total N) can be highly variable across space and time and is often one of the top concerns for site selection and permitting. This study questions the relative importance of nitrogen availability on the yield of <i>Saccharina latissima</i> (sugar kelp) across five commercial farms on the U.S. East and West Coasts over two seasons, highlighting the relative influence of other interacting factors (i.e., farm design). We hypothesized that nitrate would strongly correlate with the harvested yield. Our results show significant spatial and annual variability in the kelp yield and ambient nutrients across and within farms, but with weak covariance. Standard linear regression suggests that seawater nitrogen is a poor explanatory factor for kelp yield, explaining 11.0% of the variation around the mean compared to the line spacing (explaining 26.1%) and the interaction between the total N and the line spacing (explaining 50.0%). Quartile regression, however, suggests that total N alone, is the strongest predictor of a lower threshold in terms of the yield (0.10 quartile, r<sup>2</sup> = 0.431) relative to the median (0.50 quartile, r<sup>2</sup> 0.081). As such, seawater nitrogen may be a more useful metric in predicting baseline kelp yields rather than realized yields, and production above that baseline is likely more dependent on other factors that may or may not interact with seawater nitrogen.https://www.mdpi.com/2673-9410/4/3/20kelpseaweednitrogenaquaculturemaricultureline spacing |
| spellingShingle | Tiffany Stephens Yaoguang Li Charles Yarish Matthew C. Rogers Schery Umanzor Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? Phycology kelp seaweed nitrogen aquaculture mariculture line spacing |
| title | Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? |
| title_full | Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? |
| title_fullStr | Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? |
| title_full_unstemmed | Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? |
| title_short | Does Seawater Nitrogen Better Predict the Baseline Farmed Yield for Sugar Kelp (<i>Saccharina latissima</i>) Rather than the Final Yield? |
| title_sort | does seawater nitrogen better predict the baseline farmed yield for sugar kelp i saccharina latissima i rather than the final yield |
| topic | kelp seaweed nitrogen aquaculture mariculture line spacing |
| url | https://www.mdpi.com/2673-9410/4/3/20 |
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