{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:35:42Z","timestamp":1760150142245,"version":"build-2065373602"},"reference-count":53,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2023,10,18]],"date-time":"2023-10-18T00:00:00Z","timestamp":1697587200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"International Cooperation in Science and Technology Innovation among Governments","award":["2019YFE0127200","42022045","2022ZDLSF06-09"],"award-info":[{"award-number":["2019YFE0127200","42022045","2022ZDLSF06-09"]}]},{"name":"National Natural Science Foundation of China","award":["2019YFE0127200","42022045","2022ZDLSF06-09"],"award-info":[{"award-number":["2019YFE0127200","42022045","2022ZDLSF06-09"]}]},{"name":"Shan\u2019xi Key Research and Development Program","award":["2019YFE0127200","42022045","2022ZDLSF06-09"],"award-info":[{"award-number":["2019YFE0127200","42022045","2022ZDLSF06-09"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Algal cell abundance weakly depends on inherent optical properties and chlorophyll-a concentration in the Bohai Sea, so it is very hard to derive algal cell abundance (ACA) from ocean color data using a simple bio-optical model. To obtain ACA for biological communication at large scale, a neural network model has been developed and then applied for investigating the changing monthly trend of ACA, intracellular chlorophyll-a concentration, and cell size in the Bohai Sea using MODIS data from 2002 to 2015. The results showed that the neural network model could provide an accurate log-transformed value of algal cell abundance (LACA) from ocean color images whose retrieval uncertainty did not exceed 9%. Furthermore, when the model was applied to map the monthly mean LACA and then further convert it to cell size in the Bohai Sea, the results showed that the satellite-derived monthly mean cell size varied from 4.81 to 15.29 \u03bcm. The decreasing monthly mean algal cell abundance and increasing monthly mean chlorophyll-a concentration imply that the monthly mean intracellular chlorophyll-a concentration from 2002 to 2015 increased, which indicates that the waters in the Bohai Sea became more eutrophic over those 14 years. Moreover, due to seasonal variations in vertical mixing or other physical forcing factors, the ACA and cell size exhibited significant seasonal variations. Although further tests are required to validate the model\u2019s robustness, these preliminary results indicate that the neural network model is an encouraging approach to exploiting more novel biological parameters such as the LACA from ocean color satellites for oceanic communication.<\/jats:p>","DOI":"10.3390\/rs15204999","type":"journal-article","created":{"date-parts":[[2023,10,18]],"date-time":"2023-10-18T10:36:56Z","timestamp":1697625416000},"page":"4999","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Algal Biological Features Viewed in Satellite Observations: A Case Study of the Bohai Sea"],"prefix":"10.3390","volume":"15","author":[{"given":"Wenting","family":"Quan","sequence":"first","affiliation":[{"name":"School of Human Settlements and Civil Engineering, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"},{"name":"Shaanxi Meteorological Service Center of Agricultural Remote Sensing and Economic Corporation, Xi\u2019an 710000, China"}]},{"given":"Jun","family":"Chen","sequence":"additional","affiliation":[{"name":"Key Laboratory of Physical Electronics and Devices, Ministry of Education, Faculty of Electronic and Information Engineering, Xi\u2019an Jiaotong University, Xi\u2019an 710049, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,10,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1890\/09-1207.1","article-title":"Abandoning Sverdrup\u2019s Critical Depth Hypothesis on phytoplankton blooms","volume":"91","author":"Behrenfeld","year":"2010","journal-title":"Ecology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"290","DOI":"10.3800\/pbr.17.290","article-title":"Diversity of algal cell and the algal bloom event in the mariculture areas of Johor Strait, Malaysia","volume":"17","author":"Razali","year":"2022","journal-title":"Plankton Benthos Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"880","DOI":"10.1038\/nclimate2349","article-title":"Climate-mediated dance of the phytoplankton","volume":"4","author":"Behrenfeld","year":"2014","journal-title":"Nat. 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