Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary

Understanding macroalgal bloom development is crucial for managing eutrophication and protecting estuarine ecosystems. In this study, brown macroalgal blooms (i.e., golden tides) were identified in a potentially eutrophic temperate estuary (NW Ireland). <i>Pylaiella littoralis</i> (Phaeo...

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Main Authors: Sara Haro, Ricardo Bermejo, Mark G. Healy, Kay Knöeller, Owen Fenton, Svenja Heesch, Liam Morrison
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Journal of Marine Science and Engineering
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Online Access:https://www.mdpi.com/2077-1312/12/12/2336
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author Sara Haro
Ricardo Bermejo
Mark G. Healy
Kay Knöeller
Owen Fenton
Svenja Heesch
Liam Morrison
author_facet Sara Haro
Ricardo Bermejo
Mark G. Healy
Kay Knöeller
Owen Fenton
Svenja Heesch
Liam Morrison
author_sort Sara Haro
collection DOAJ
description Understanding macroalgal bloom development is crucial for managing eutrophication and protecting estuarine ecosystems. In this study, brown macroalgal blooms (i.e., golden tides) were identified in a potentially eutrophic temperate estuary (NW Ireland). <i>Pylaiella littoralis</i> (Phaeophyceae, Ectocarpales) was monitored at low tide over seven sampling occasions between June 2016 and August 2017. <i>In situ</i> biomass, tissue nutrients (nitrogen (N) and phosphorus (P)), and isotopic signature (δ<sup>15</sup>N contents) were measured, and relations with environmental drivers were explored. Difference Vegetation Index (NDVI) values from Sentinel-2 satellite imagery were used to assess the spatiotemporal dynamics of <i>P. littoralis</i> biomass (2016–2022). The results indicated that NDVI attributed to golden tides were lowest in 2022, during summer (coinciding with high temperatures and high rainfall) and at the lower shore on the right margin of an entering river. The highest tissue P content was recorded in April 2017, coinciding with <i>in situ</i> biomass peaks (spring–early summer), suggesting elevated P demand. Tissue N content (>2%) and N:P ratios (10–30) indicated occasional P limitation but no N limitation. δ<sup>15</sup>N data were very low and it was not possible to identify any primary N source. These findings highlight the importance of nutrient management in mitigating golden tides, addressing eutrophication, and preserving estuarine ecosystems.
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spelling doaj-art-95a95bfbcf56490685c15fc9f83e7a4e2025-08-20T02:00:23ZengMDPI AGJournal of Marine Science and Engineering2077-13122024-12-011212233610.3390/jmse12122336Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal EstuarySara Haro0Ricardo Bermejo1Mark G. Healy2Kay Knöeller3Owen Fenton4Svenja Heesch5Liam Morrison6Earth and Life Sciences, School of Natural Sciences and Ryan Institute, University of Galway, H91 TK33 Galway, IrelandDepartment of Ecology and Geology, Faculty of Sciences, University of Malaga, 29010 Málaga, SpainCivil Engineering and Ryan Institute, University of Galway, H91 TK33 Galway, IrelandDepartment of Catchment Hydrology, Helmholtz Centre for Environmental Research, D-06120 Halle, GermanyTeagasc, Environment Research Centre, Johnstown Castle, Y35 Y521 Wexford, IrelandInstitute for Biological Sciences, University of Rostock, Albert-Einstein-Straße 3, D-18059 Rostock, GermanyEarth and Life Sciences, School of Natural Sciences and Ryan Institute, University of Galway, H91 TK33 Galway, IrelandUnderstanding macroalgal bloom development is crucial for managing eutrophication and protecting estuarine ecosystems. In this study, brown macroalgal blooms (i.e., golden tides) were identified in a potentially eutrophic temperate estuary (NW Ireland). <i>Pylaiella littoralis</i> (Phaeophyceae, Ectocarpales) was monitored at low tide over seven sampling occasions between June 2016 and August 2017. <i>In situ</i> biomass, tissue nutrients (nitrogen (N) and phosphorus (P)), and isotopic signature (δ<sup>15</sup>N contents) were measured, and relations with environmental drivers were explored. Difference Vegetation Index (NDVI) values from Sentinel-2 satellite imagery were used to assess the spatiotemporal dynamics of <i>P. littoralis</i> biomass (2016–2022). The results indicated that NDVI attributed to golden tides were lowest in 2022, during summer (coinciding with high temperatures and high rainfall) and at the lower shore on the right margin of an entering river. The highest tissue P content was recorded in April 2017, coinciding with <i>in situ</i> biomass peaks (spring–early summer), suggesting elevated P demand. Tissue N content (>2%) and N:P ratios (10–30) indicated occasional P limitation but no N limitation. δ<sup>15</sup>N data were very low and it was not possible to identify any primary N source. These findings highlight the importance of nutrient management in mitigating golden tides, addressing eutrophication, and preserving estuarine ecosystems.https://www.mdpi.com/2077-1312/12/12/2336seaweedbioindicatornutrientswater qualityeutrophicationremote sensing
spellingShingle Sara Haro
Ricardo Bermejo
Mark G. Healy
Kay Knöeller
Owen Fenton
Svenja Heesch
Liam Morrison
Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
Journal of Marine Science and Engineering
seaweed
bioindicator
nutrients
water quality
eutrophication
remote sensing
title Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
title_full Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
title_fullStr Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
title_full_unstemmed Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
title_short Seasonal Variability of Golden Tides (<i>Pylaiella littoralis</i>, Phaeophyceae) and Nutrient Dynamics in a Potentially Eutrophic Intertidal Estuary
title_sort seasonal variability of golden tides i pylaiella littoralis i phaeophyceae and nutrient dynamics in a potentially eutrophic intertidal estuary
topic seaweed
bioindicator
nutrients
water quality
eutrophication
remote sensing
url https://www.mdpi.com/2077-1312/12/12/2336
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