Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models

Since the mid-1980s, the Mediterranean Sea’s surface and deeper layers have warmed at unprecedented rates, with recent projections identifying it as one of the regions most impacted by rising global temperatures. Metrics that characterize phytoplankton abundance, phenology and size structure are wid...

Full description

Saved in:
Bibliographic Details
Main Authors: John A. Gittings, Eleni Livanou, Xuerong Sun, Robert J. W. Brewin, Stella Psarra, Manolis Mandalakis, Alexandra Peltekis, Annalisa Di Cicco, Vittorio E. Brando, Dionysios E. Raitsos
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/17/14/2362
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849732764389081088
author John A. Gittings
Eleni Livanou
Xuerong Sun
Robert J. W. Brewin
Stella Psarra
Manolis Mandalakis
Alexandra Peltekis
Annalisa Di Cicco
Vittorio E. Brando
Dionysios E. Raitsos
author_facet John A. Gittings
Eleni Livanou
Xuerong Sun
Robert J. W. Brewin
Stella Psarra
Manolis Mandalakis
Alexandra Peltekis
Annalisa Di Cicco
Vittorio E. Brando
Dionysios E. Raitsos
author_sort John A. Gittings
collection DOAJ
description Since the mid-1980s, the Mediterranean Sea’s surface and deeper layers have warmed at unprecedented rates, with recent projections identifying it as one of the regions most impacted by rising global temperatures. Metrics that characterize phytoplankton abundance, phenology and size structure are widely utilized as ecological indicators that enable a quantitative assessment of the status of marine ecosystems in response to environmental change. Here, using an extensive, updated in situ pigment dataset collated from numerous past research campaigns across the Mediterranean Sea, we re-parameterized an abundance-based phytoplankton size class model that infers Chl-a concentration in three phytoplankton size classes: pico- (<2 μm), nano- (2–20 μm) and micro-phytoplankton (>20 μm). Following recent advancements made within this category of size class models, we also incorporated information of sea surface temperature (SST) into the model parameterization. By tying model parameters to SST, the performance of the re-parameterized model was improved based on comparisons with concurrent, independent in situ measurements. Similarly, the application of the model to remotely sensed ocean color observations revealed strong agreement between satellite-derived estimates of phytoplankton size structure and in situ observations, with a performance comparable to the current regional operational datasets on size structure. The proposed conceptual regional model, parameterized with the most extended in situ pigment dataset available to date for the area, serves as a suitable foundation for long-term (1997–present) analyses on phytoplankton size structure and ecological indicators (i.e., phenology), ultimately linking higher trophic level responses to a changing Mediterranean Sea.
format Article
id doaj-art-5b3f9e3b1334474cbe28c879d45845a2
institution DOAJ
issn 2072-4292
language English
publishDate 2025-07-01
publisher MDPI AG
record_format Article
series Remote Sensing
spelling doaj-art-5b3f9e3b1334474cbe28c879d45845a22025-08-20T03:08:13ZengMDPI AGRemote Sensing2072-42922025-07-011714236210.3390/rs17142362Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based ModelsJohn A. Gittings0Eleni Livanou1Xuerong Sun2Robert J. W. Brewin3Stella Psarra4Manolis Mandalakis5Alexandra Peltekis6Annalisa Di Cicco7Vittorio E. Brando8Dionysios E. Raitsos9Department of Biology, National and Kapodistrian University of Athens, 15772 Athens, GreeceDepartment of Biology, National and Kapodistrian University of Athens, 15772 Athens, GreeceCentre for Geography and Environmental Science, Department of Earth and Environmental Sciences, Faculty of Environment, Science and Economy, University of Exeter, Cornwall TR10 9FE, UKCentre for Geography and Environmental Science, Department of Earth and Environmental Sciences, Faculty of Environment, Science and Economy, University of Exeter, Cornwall TR10 9FE, UKInstitute of Oceanography, Hellenic Centre for Marine Research, 71003 Heraklion, GreeceInstitute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, 71003 Heraklion, GreeceInstitute of Oceanography, Hellenic Centre for Marine Research, 71003 Heraklion, GreeceConsiglio Nazionale delle Ricerche, Istituto di Scienze Marine (CNR-ISMAR), 00133 Rome, ItalyConsiglio Nazionale delle Ricerche, Istituto di Scienze Marine (CNR-ISMAR), 00133 Rome, ItalyDepartment of Biology, National and Kapodistrian University of Athens, 15772 Athens, GreeceSince the mid-1980s, the Mediterranean Sea’s surface and deeper layers have warmed at unprecedented rates, with recent projections identifying it as one of the regions most impacted by rising global temperatures. Metrics that characterize phytoplankton abundance, phenology and size structure are widely utilized as ecological indicators that enable a quantitative assessment of the status of marine ecosystems in response to environmental change. Here, using an extensive, updated in situ pigment dataset collated from numerous past research campaigns across the Mediterranean Sea, we re-parameterized an abundance-based phytoplankton size class model that infers Chl-a concentration in three phytoplankton size classes: pico- (<2 μm), nano- (2–20 μm) and micro-phytoplankton (>20 μm). Following recent advancements made within this category of size class models, we also incorporated information of sea surface temperature (SST) into the model parameterization. By tying model parameters to SST, the performance of the re-parameterized model was improved based on comparisons with concurrent, independent in situ measurements. Similarly, the application of the model to remotely sensed ocean color observations revealed strong agreement between satellite-derived estimates of phytoplankton size structure and in situ observations, with a performance comparable to the current regional operational datasets on size structure. The proposed conceptual regional model, parameterized with the most extended in situ pigment dataset available to date for the area, serves as a suitable foundation for long-term (1997–present) analyses on phytoplankton size structure and ecological indicators (i.e., phenology), ultimately linking higher trophic level responses to a changing Mediterranean Sea.https://www.mdpi.com/2072-4292/17/14/2362phytoplankton size structureocean colorremote sensingecological indicators
spellingShingle John A. Gittings
Eleni Livanou
Xuerong Sun
Robert J. W. Brewin
Stella Psarra
Manolis Mandalakis
Alexandra Peltekis
Annalisa Di Cicco
Vittorio E. Brando
Dionysios E. Raitsos
Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
Remote Sensing
phytoplankton size structure
ocean color
remote sensing
ecological indicators
title Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
title_full Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
title_fullStr Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
title_full_unstemmed Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
title_short Remotely Sensing Phytoplankton Size Structure in the Mediterranean Sea: Insights from In Situ Data and Temperature-Corrected Abundance-Based Models
title_sort remotely sensing phytoplankton size structure in the mediterranean sea insights from in situ data and temperature corrected abundance based models
topic phytoplankton size structure
ocean color
remote sensing
ecological indicators
url https://www.mdpi.com/2072-4292/17/14/2362
work_keys_str_mv AT johnagittings remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT elenilivanou remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT xuerongsun remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT robertjwbrewin remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT stellapsarra remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT manolismandalakis remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT alexandrapeltekis remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT annalisadicicco remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT vittorioebrando remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels
AT dionysioseraitsos remotelysensingphytoplanktonsizestructureinthemediterraneanseainsightsfrominsitudataandtemperaturecorrectedabundancebasedmodels