A Global Bibliometric Analysis of Seaweed Biodiversity, Endemic Taxa, and Conservation (1992–2023)

Abstract

Marine habitats are increasingly facing human-induced stressors, posing significant threats to global marine biodiversity. Understanding the ecological, economic, and social importance of marine ecosystems is paramount. This study conducts a comprehensive bibliometric analysis of seaweed biodiversity from 1992 to 2023, aiming to (i) quantify the literature productivity, (ii) identify the active countries, (iii) determine the prolific authors, (iv) highlight the highly cited publications, and (v) enumerate the influential journals. The average annual number of publications was 37. Australia and the USA ranked highest based on the total number of citations, with 7559 and 5273, respectively. The University of Western Australia led in terms of the total number of citations, with 3688 citations from 40 publications, while the Australian Research Council emerged as the top funder. Journals such as the Journal of Experimental Marine Biology and Ecology, Ecology, and Botanica Marina were identified as the top contributors. The keyword ‘biodiversity’ appeared 146 times, with a total link strength of 425. A similar analysis was presented for endemic seaweeds and their conservation. Among the seven major and four emerging drivers, climate change was the most researched driver, accounting for 45.80%, with 120 articles. This study anticipates that in the genomic era, seaweed biodiversity will receive increased attention for its potential in regard to the development of coherent conservation plans and innovative bioprospecting strategies that are beneficial to humankind.

1. Introduction

The term ‘biodiversity’ was first used by Lovejoy in the long version of their work (biological diversity), and he used it to describe the number of species [1]. In addition to species diversity, biodiversity can also be defined as the number of species in an area and their relative abundance [2]. Biodiversity also refers to the variety within and among living organisms, assemblages of living organisms, biotic communities, and processes. In addition, it can be determined in terms of genetic diversity, the identity and number of different types of species, the assemblages of species, and the amount and structure of each species. Biodiversity can also be studied at any spatial scale, ranging from microsites and habitat patches to the entire biosphere [3]. The term ‘endemic’ refers to the state of a species or taxon that is found to be restricted to a given area, such as a specific habitat, region, or continent [2].

The United Nations General Assembly, during its 65th session in 2010, called upon the United Nations Environment Program to convene a plenary meeting to establish the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) [4]. Consequently, the IPBES was established in 2012. Its inaugural comprehensive report, the “Global Assessment of the State of Biodiversity and Ecosystem Services”, was released in 2019 [5]. The global assessment, spanning the past 50 years, involving 145 authors from across 50 countries, revealed that biodiversity has suffered an unprecedented decline due to human-induced changes. These alterations have been linked to the ever-growing population (which has doubled in the corresponding years) and per capita gross domestic product (which has quadrupled in the corresponding years). In addition to several observations, the report highlighted an urgent need to be proactive in regard to restoring habitats, producing food with minimal requirements, reducing pollution, and protecting marine habitats [5]. Marine habitats increasingly experience human-induced stressors; consequently, global marine biodiversity is in peril [6]. It has been considered that marine biodiversity assessments are yet to be fully developed compared to other types of assessments. This is primarily due to the inadequate integration into and representation of certain groups, e.g., seaweeds, in marine environmental monitoring programs [7].

Seaweeds are macroscopic algae that are important to ecosystem services and the marine economy. Further, this term is used for artificial, heterogeneous, and phylogenetically unrelated assemblages [8]. It may be noted that, based on pigment composition, they are artificially classified into three phyla, namely Chlorophyta (green algae), Heterokontophyta (brown algae), and Rhodophyta (red algae). The two dominant classes of marine green algae are represented by Chlorophyceae and Ulvophyceae, having 3974 and 2695 species, respectively, while over 2124 species of marine brown algae are reported in regard to Phaeophyceae; red algae are divided into Bangiophyceae and Florideophyceae classes, with 185 and 7155 species, respectively [9]. The ecological, economic, and social contributions of seaweed are high. Being rich in vital nutrients, seaweed has served as a food source for coastal communities in many countries. However, excessive consumption may pose health risks due to its high iodine content and the potential accumulation of heavy metals [10]. Additionally, this resource offers essential environmental advantages through its incorporation into ecosystem services in natural habitats or aquaculture operations [8]. Thus, seaweed has gained considerable prominence due to consumer demand for developing commodity products, ubiquitous distribution, and increased sustainable farming technologies. As per the recent report by the Food and Agriculture Organization of the United Nations, the global cultivation of algae, dominated by seaweeds, achieved an annual production amount of 36 million tons (wet weight basis), which is 98% of total worldwide production in 2020 [11]. It is worth mentioning here that 97% (31.5 million tons) of total worldwide production was contributed through aquaculture [8]. Seaweed farming has considerable relevance to several Sustainable Development Goals (SDGs), e.g., SDG1 No Poverty; SDG2 Zero Hunger; SDG3 Good Health and Well-being; SDG 8 Decent Work and Economic Growth; SDG10 Reducing Inequality; SDG 12 Responsible Consumption and Production; SDG 13 Climate Action; and SDG 14 Life Below Water [12]. Recent global initiatives, such as the Global Seaweed Coalition and GlobalSeaweed-SUPERSTAR, play a pivotal role in advancing the sustainable development of seaweed resources. The Global Seaweed Coalition aims to promote the sustainable use of seaweed by addressing issues related to biodiversity, conservation, and the global seaweed economy [13]. Similarly, GlobalSeaweed-SUPERSTAR focuses on protecting, enhancing, and restoring biodiversity while supporting livelihoods by ensuring the sustainability of the seaweed aquaculture industry in developing countries [14]. These initiatives align with the objectives of this study and are integral to ongoing efforts in conserving and managing seaweed biodiversity.

Against this backdrop, the purpose of the present study was to analyze the global literature contribution published between 1992 and 2023 from the perspective of seaweed biodiversity, endemic seaweed, and the conservation of seaweed. The study (i) examined year-wise literature productivity, (ii) identified the most active countries, (iii) pinpointed the prolific authors, (iv) highlighted the highly cited publications, and (v) enumerated the journals with high influence. We also identified the major and emerging drivers of biodiversity loss, which might aid conservation efforts. To our knowledge, this is the first-ever global comprehensive bibliometric analysis of seaweed biodiversity, including endemic taxa and conservation.

2. Methodology and Data Analysis

In the present study, raw data were generated from the Web of Science (WoS) on 4 September 2024, focusing exclusively on research and review article document types. This study exclusively analyzed peer-reviewed articles retrieved from the Web of Science (WoS) database to ensure the reliability and validity of the data. The dataset on seaweed biodiversity, endemic seaweed, and the conservation of seaweed was analyzed between 1992 and 2023. The search used topic-wise filters with keywords such as ‘seaweed biodiversity’, ‘endemic seaweed’, and ‘conservation of seaweed’, resulting in 747, 184, and 459 publications, respectively. Additionally, searching for articles on seaweed research using ‘macroalgae’ as a keyword was conducted to ensure comprehensive coverage, resulting in 1149, 201, and 604 publications for seaweed biodiversity, endemic seaweed, and conservation, respectively (Supplementary Table S1). Special attention was given to the top ten seaweed-producing countries [8], for which we performed individual searches using the country’s name in combination with the keywords as mentioned above. These searches yielded an additional 116, 32, and 106 publications for ‘seaweed biodiversity’, ‘endemic seaweed’, and ‘conservation of seaweed’, respectively (Supplementary Table S2). The three searches yielded a total of 2012, 417, and 1169 publications for ‘seaweed biodiversity’, ‘endemic seaweed’, and ‘conservation of seaweed’, respectively. However, these topics fall under interdisciplinary areas. Therefore, we manually reviewed all the results to extract the core findings. The data were subsequently reduced to 706, 153, and 107 publications, respectively, as summarized in Figure 1. We exported this dataset to Excel format and analyzed it for various parameters. Among these publications, the data were categorized into eleven different drivers of biodiversity loss, namely: climate change, water pollution, invasive species, anthropogenic impact, habitat degradation, unsustainable exploitation, and introduced species (seven major drivers), as well as outdoor activities, tourism, deforestation and coastal development, diseases, and epiphytism (four emerging drivers) [15,16,17,18].

2.1. Criteria for Study

This study provided the necessary data for conducting the following analyses: total publications (TPs), percentage of total publications (% of TPs), total citations (TCs), average citations per paper (ACPP), and h-index for active countries, as well as year-wise analysis, top authors, and top journals. Additionally, for the top publications, information including the author, year, affiliation, top journals, and TCs was selected for further investigation for all three mentioned topics.

2.2. Network Visualization Analysis

The VOS viewer (Version 1.6.20) is a software tool for creating bibliometric maps from network data obtained from WoS. We analyzed bibliographic data obtained from WoS using VOS viewer software to assess the volume and impact of research activities and to explore the interactions between researchers, countries, and fields of knowledge (developed by Universiteit Leiden, The Netherlands) [19]. This analysis enabled us to construct and visualize bibliometric networks based on citations, bibliographic coupling, authorship patterns of countries, and journals for all three topics mentioned above.

3. Results

3.1. Seaweed Biodiversity Research

3.1.1. Most Active Countries in Seaweed Biodiversity Research—Global Scenario

The analysis revealed 750 articles published globally from 1992 to 2023 on seaweed biodiversity research. Bibliometric analysis of the top 10 countries showed the global publication contribution for these countries ranged from 1.60% (Wales) to 18.13% (USA) (Figure 2 and Figure 3; Supplementary Table S3). Among the top active countries, Australia ranked first based on total citations (TCs) of 7559, with 16.53% of total publications. The USA ranked second with 5273 TCs and 18.13% publications. England ranked third with 3344 TCs, followed by Spain (3063 TCs), France (1843 TCs), Italy (1660 TCs), Portugal (1599 TCs), Wales (1501 TCs), North Ireland (1488 TCs), and New Zealand (1392 TCs). The other prolific and influential countries, such as Brazil, Canada, Japan, Germany, Ireland, China, Mexico, Norway, Greece, and Chile, had 7.07, 5.87, 4.27, 4.13, 3.87, 3.73, 3.73, 3.60, 3.60, and 3.33% of the total publications respectively. Despite their relatively lower citation counts than the leading nations, these countries have made meaningful contributions to advancing the field.

The total citations and h-index are essential indicators of research value and influence. Thus,

Table 1. Most active countries in seaweed biodiversity research during 1992–2023 per WoS search of countries, academic institutions, and funding agencies based on number of citations.

Countries (WoS)				Academic Institutions				Funding Agencies
Name	TP	TC	h-Index	Name	TP	TC	h-Index	Name	TP	TC	h-Index
Australia	124	7559	44	University of Western Australia, Australia	40	3688	24	Australian Research Council, Australia	32	3310	24
USA	136	5273	39	Australian Institute of Marine Science, Australia	15	2791	15	National Science Foundation NSF, USA	42	1571	21
England	68	3344	27	Edith Cowan University, Australia	10	2061	10	European Union EU, Belgium	48	1533	18
Spain	79	3063	26	Queens University Belfast, Ireland	13	1482	10	UK Research Innovation UKRI, UK	28	1354	16
France	74	1843	25	Marine Biological Association United Kingdom, England	20	1546	12	Natural Environment Research Council NERC, UK	22	1324	16
Italy	75	1660	23	Centre National De La Recherche Scientifique CNRS, France	50	1319	21	The Foundation for Science and Technology, Portugal	53	1118	18
Portugal	68	1599	22	Ghent University, Belgium	19	1207	12	Spanish Government, Spain	22	852	15
Wales	12	1501	11	Sorbonne Universite, France	38	1023	19	Natural Sciences and Engineering Research Council of Canada NSERC, Canada	25	713	16
North Ireland	14	1488	10	Universidade do Porto, Spain	33	855	15	National Council for Scientific and Technological Development CNPQ, Brazil	28	523	12
New Zealand	43	1392	21	University of California system, USA	26	806	14	Coordination for the Improvement of Higher Education Personnel CAPES, Brazil	20	432	11

depicts these data for the research papers published by the top active institutions representing their countries between 1992 and 2023. The University of Western Australia, Australia, ranked first with 3688 total citations (TCs) of 40 total publications (TPs) followed by the Australian Institute of Marine Science, Australia (2791 TCs, 15 TPs), Edith Cowan University, Australia (2061 TCs, 10 TPs), Queen’s University Belfast, Ireland (1482 TCs, 13 TPs), Marine Biological Association United Kingdom, England (1546 TCs, 20 TPs), Centre National De La Recherche Scientifique CNRS, France (1319 TCs, 50 TPs), Ghent University, Belgium (1207 TCs, 12 TPs), Sorbonne Universite, France (1023 TCs, 38 TPs), Universidade do Porto, Spain (855 TCs, 33 TPs), and the University of California system, USA (806 TCs, 26 TPs). Nevertheless, based on total publications, the Centre National De La Recherche Scientifique CNRS, France, secured first position with 50 TPs, while the Edith Cowan University, Australia, ranked last with 10 TPs.

The funding agencies depicted in Table 1 represent their countries in terms of funding research on seaweed biodiversity. The Australian Research Council, Australia, secured first position based on 3310 total citations (TCs) of 32 total publications (TPs) followed by the National Science Foundation NSF, USA (1571 TCs, 42 TPs), the European Union EU, Belgium (1533 TCs, 48 TPs), UK Research Innovation UKRI, UK (1354 TCs, 28 TPs), the Natural Environment Research Council NERC, UK (1324 TCs, 22 TPs), The Foundation for Science and Technology, Portugal (1118 TCs, 53 TPs), the Spanish Government, Spain (852 TCs, 22 TPs), the Natural Sciences and Engineering Research Council of Canada NSERC, Canada (713 TCs, 25 TPs), the National Council for Scientific and Technological Development CNPQ, Brazil (523 TCs, 28 TPs), and the Coordination for the Improvement of Higher Education Personnel CAPES, Brazil (432 TCs, 20 TPs).

3.1.2. Year-Wise Distribution of Publications

The growth in publications was not constant between 2004 and 2023. Instead, there are fluctuations in the publication rates during this period, and the decrease is not consistently linear. Figure 4 and Supplementary Table S4 depict the year-wise distribution of publications from 1992 to 2023. While there is a general trend of growth in publications, there are fluctuations in the publication rates over time. The period from 1992 to 2003 can be identified as the commencement period, marking the initiation of focused research. From 2004 to 2023, there was a trend of steady extension, with efforts in research augmented. However, the growth is not constant, and publication rates vary during this period. The maximum number of 68 publications (TPs) was recorded in 2020, corresponding to 1017 citations. This was followed by 66 TPs in 2019, with 1499 citations. The quality assessment of the countries, in terms of the average citations per paper (ACCP), revealed that the ACCP ranged from 0 (1992) to 87 (2005), indicating variations in the citation impact over time. At the same time, the overall average publications per year (APPY) was 37. It may be noted that 2013 contributed the highest number of citations with 2853 TCs and 58 ACPP, while 1992 ranked last in the citation list with no citations.

3.1.3. Citation Analysis of the Top Publications and Authors

The highly cited publications in seaweed biodiversity research are listed in Table 2. The most cited publication was found to be “An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot”, with a total of 762 citations, according to WoS. In contrast, the least cited publication was “Consumer diversity interacts with prey defenses to drive ecosystem function”, with 202 total citations, per WoS. Between 1992 and 2023, T. Wernberg was the most productive author with 17 publications with 2560 citations, followed by D.A. Smale with 16 TPs with 2427 citations; M.S. Thomsen, 17 TPs with 1814 citations; O. De Clerck, 16 TPs with 1086 citations; M.A. Coleman, 14 TPs with 1038 citations; S. Bennett, 3 TPs with 1002 citations; T. De Bettignies, 2 TPs with 872 citations; H. Verbruggen, 9 TPs with 864 citations; S.J. Hawkins, 4 TPs with 857 citations; and P.J. Moore, 4 TPs with 716 citations (Figure 5; Supplementary Table S5). As per TCs (2560) with ACPP (151) records, T. Wernberg secured first place in the list, while as per 17 TPs and 2.27% of TP records, T. Wernberg and M.S. Thomsen equally shared first place.

The most highly cited research in seaweed biodiversity has focused on the geographical distribution and on developing global environmental datasets for marine species [20,21]. Significant studies have also examined the effects of climatic events like global warming on seaweed survival and ecosystem structure [22,23]. Marine heatwaves have caused stepwise changes in species distribution and habitat loss among key seaweed [24]. Furthermore, research has shown how climatic and non-climatic stressors reshape coastal ecosystems [25,26]. Additionally, researchers have explored the role of kelp as a habitat-forming species in coastal ecosystems [27], while studies have investigated the impacts of water quality on marine communities, including seaweed, corals, and fish [28].

Table 2. Publication records and citation analysis of top highly cited publications on seaweed biodiversity research.

Title	Affiliation	Source Title	Total Citations	References
“An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot”	University of Western Australia, Australia	Nature Climate Change	762	[23]
“Bio-ORACLE: a global environmental dataset for marine species distribution modelling”	Ghent University, Ghent, Belgium	Global Ecology and Biogeography	659	[21]
“Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective”	Marine Biological Association UK, England	Ecology and Evolution	362	[25]
“Extreme climatic event drives range contraction of a habitat-forming species”	University of Western Australia, Australia	Proceedings of The Royal Society B-Biological Sciences	356	[24]
“The role of kelp species as biogenic habitat formers in coastal marine ecosystems”	Marine Biological Association UK, England	Journal of Experimental Marine Biology and Ecology	341	[27]
“Changes in algal, coral and fish assemblages along water quality gradients on the inshore Great Barrier Reef”	Australian Institute of Marine Science, Townsville, Australia	Marine Pollution Bulletin	336	[28]
“Impacts of climate change in a global hotspot for temperate marine biodiversity and ocean warming”	University of Western Australia, Australia	Journal of Experimental Marine Biology and Ecology	311	[22]
“Seaweed communities in retreat from ocean warming”	University of Western Australia, Australia	Current Biology	276	[22]

Table 2. Publication records and citation analysis of top highly cited publications on seaweed biodiversity research.

Title	Affiliation	Source Title	Total Citations	References
“An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot”	University of Western Australia, Australia	Nature Climate Change	762	[23]
“Bio-ORACLE: a global environmental dataset for marine species distribution modelling”	Ghent University, Ghent, Belgium	Global Ecology and Biogeography	659	[21]
“Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective”	Marine Biological Association UK, England	Ecology and Evolution	362	[25]
“Extreme climatic event drives range contraction of a habitat-forming species”	University of Western Australia, Australia	Proceedings of The Royal Society B-Biological Sciences	356	[24]
“The role of kelp species as biogenic habitat formers in coastal marine ecosystems”	Marine Biological Association UK, England	Journal of Experimental Marine Biology and Ecology	341	[27]
“Changes in algal, coral and fish assemblages along water quality gradients on the inshore Great Barrier Reef”	Australian Institute of Marine Science, Townsville, Australia	Marine Pollution Bulletin	336	[28]
“Impacts of climate change in a global hotspot for temperate marine biodiversity and ocean warming”	University of Western Australia, Australia	Journal of Experimental Marine Biology and Ecology	311	[22]
“Seaweed communities in retreat from ocean warming”	University of Western Australia, Australia	Current Biology	276	[22]

3.1.4. Top Productive Journals

Among the top productive journals in the area of seaweed biodiversity research, the Journal of Experimental Marine Biology and Ecology ranked first based on 1224 TCs of 14 TPs, followed by Ecology (1121 TCs, 17 TPs), Botanica Marina (983 TCs, 33 TPs), Plos One (931 TCs, 23 TPs), Global Ecology and Biogeography (832 TCs, 6 TPs), Marine Pollution Bulletin (756 TCs, 15 TPs), Ecology and Evolution (649 TCs, 9 TPs), Estuarine Coastal and Shelf Science (579 TCs, 18 TPs), Biological Invasions (548 TCs, 15 TPs), and the Journal of Applied Phycology (509 TCs, 20 TPs). As per the publication record, Botanica Marina ranked first with 33 TPs, while Global Ecology and Biogeography ranked last with 6 TPs (Figure 6 and

Table 3. Publication records and citation analysis of top journals on seaweed biodiversity research.

Source Title	TPs	% of TPs	TCs	ACPP	h-Index
Journal of Experimental Marine Biology and Ecology	14	1.87	1224	87	11
Ecology	17	2.27	1121	66	15
Botanica Marina	33	4.40	983	30	15
Plos One	23	3.07	931	41	17
Global Ecology and Biogeography	6	0.80	832	139	6
Marine Pollution Bulletin	15	2.00	756	50	10
Ecology and Evolution	9	1.20	649	72	7
Estuarine Coastal and Shelf Science	18	2.40	579	32	14
Biological Invasions	15	2.00	548	37	11
Journal of Applied Phycology	20	2.67	509	25	10

TPs: total publications, TCs: total citations, ACPP: average citations per paper.

). According to the InCites Journal Citation Reports by Clarivate Analytics 2023 [29], the impact factor list shows that Global Ecology and Biogeography, Biological Invasions, and Marine Pollution Bulletin were the top three journals with impact factors of 6.4, 4.3, and 4.2, respectively.

3.1.5. Author Keyword Analysis

Note that, among the top 10 keywords in seaweed biodiversity research, the keyword ‘biodiversity’ occurred (OC) 146 times with a total link strength (TLS) of 425 followed by the keywords ‘macroalgae’ (OC 136, TLS 365), ‘seaweeds’ (OC 100, TLS 315), ‘climate change’ (OC 42, TLS 117), ‘Rhodophyta’ (OC 26, TLS 115), ‘algae’ (OC 27, TLS 104), ‘rbcL’ (OC 19, TLS 84), ‘taxonomy’ (OC 26, TLS 76), ‘biogeography’ (OC 23, TLS 75), and ‘kelp’ (OC 20, TLS 72) [Figure 7].

3.2. Endemic Seaweed Research

3.2.1. Most Active Countries in Endemic Seaweed Research—Global Scenario

The WoS platform of the topic-wise search for endemic seaweed recorded 135 articles published globally. Bibliometric analysis of the top 10 countries showed the global publication contribution for these countries ranged from 2.96% (The Netherlands) to 14.82% (Germany) (Supplementary Table S6; Supplementary Figures S1 and S2). Among the top active countries, Germany ranked first based on 645 TCs of 20 TPs followed by the USA (572 TCs, 19 TPs), Australia (470 TCs, 11 TPs), France (430 TCs, 13 TPs), The Netherlands (385 TCs, 4 TPs), New Zealand (309 TCs, 12 TPs), Portugal (242 TCs, 12 TPs), Brazil (242 TCs, 11 TPs), Canada (232 TCs, 10 TPs), and Spain (210 TCs, 9 TPs). The other prolific and influential countries, such as Chile, Italy, South Korea, Sweden, China, Japan, England, Belgium, Mexico, and Israel, reported 8.89, 5.93, 5.19, 4.44, 4.44, 4.44, 3.70, 3.70, 3.70, and 3.70% of the total publications, respectively. Despite their relatively lower citation counts compared to the leading nations, these countries have significantly contributed to advancing the field.

The top active institutions representing their countries for the research papers published between 1994 and 2023 are listed in Supplementary Table S7. The Alfred Wegener Institute Helmholtz Centre for Polar Marine Research, Germany ranked first based on 533 TCs of 17 TPs followed by the University of Groningen, The Netherlands (385 TCs, 4 TPs), Aix Marseille Universite, France (246 TCs, 7 TPs), the National Institute of Water & Atmospheric Research, New Zealand (202 TCs, 3 TPs), the University of Hawaii Manoa, USA (199 TCs, 2 TPs), Universidade do Algarve, Portugal (165 TCs, 8 TPs), Inst Meereskunde, Germany (160 TCs, 2 TPs), the University of Canterbury (176 TCs, 1 TP), the University of Queensland (157 TCs, 3 TPs), and Jardim Botanico Do Rio De Janeiro (150 TCs, 3 TPs).

The funding agencies representing their countries that funded endemic seaweed research are listed in Supplementary Table S7. The Portuguese Foundation for Science and Technology, Portugal, ranked first, based on 204 TCs of 10 TPs, followed by the Ministry of Business Innovation and Employment, New Zealand (182 TCs, 2 TPs), the Ministry of Primary Industries, New Zealand (177 TCs, 1 TP), the German Research Foundation DFG, Germany (130 TCs, 7 TPs), the National Science Foundation NSF, USA (115 TCs, 5 TPs), the National Council for Scientific and Technological Development CNPQ, Brazil (106 TCs, 7 TPs), the National Commission for Scientific and Technological Research, Chile (100 TCs, 6 TPs), Region Corse, France (79 TCs, 1 TP), Coordination for the Improvement of Higher Education Personnel, Brazil (70 TCs, 6 TPs), and the Norwegian Polar Institute, Norway (66 TCs, 1 TP).

3.2.2. Year-Wise Distribution of Publications

The year-wise distribution of publications on endemic seaweed research from 1994 to 2023 is listed in Supplementary Table S8 and Supplementary Figure S3. In 2020, researchers recorded the maximum of 12 TPs, corresponding to 164 citations, followed by 11 TPs in 2017 and 2019, with 157 and 310 citations, respectively. The quality assessment of the countries, when assessed in terms of the average citations per paper (ACCP), revealed that the ACCP ranged from 1 (2023) to 86 (1994, 2007). The overall average number of publications per year (APPY) was five. Note that 2007 contributed the highest number of citations, 344 with 86 ACPP, while 2023 ranked last in the citation list with 6 TCs and 1 ACPP.

3.2.3. Citation Analysis of the Top Publications and Authors

The highly cited publications in endemic seaweed research are listed in Supplementary Table S9. We found the most cited publication to be “Glacial refugia and recolonization pathways in the brown seaweed Fucus serratus”, with a total of 196 citations. Meanwhile, “Species distribution models and mitochondrial DNA phylogeography suggest an extensive biogeographical shift in the high-intertidal seaweed Pelvetia canaliculata” ranked last with 61 citations. As shown in Supplementary Table S10 and Figure S4, C. Wiencke secured the top of the list with 423 TCs of 11 TPs. In contrast, G.A. Pearson ranked last with 129 TCs of 4 TPs. The top highly cited research publications on endemic seaweed research were in the domain of biogeographical studies [30,31,32,33,34], environmental and ecological impacts [35,36], population dynamic studies [37,38], and hybridization [39].

3.2.4. Top Productive Journals

The top journals on endemic seaweed research are listed in Supplementary Table S11 and Supplementary Figure S5. Among them, Botanica Marina ranked first with 309 TCs of 11 TPs, followed by the European Journal of Phycology (303 TCs, 7 TPs), Frontiers in Marine Science (198 TCs, 4 TPs), Molecular Ecology (195 TCs, 1 TP), the Journal of Phycology (224 TCs, 9 TPs), Frontiers in Marine Science (205 TCs, 3 TPs), Polar Biology (205 TCs, 8 TPs), Molecular Ecology (196 TCs, 1 TP), Marine Ecology Progress Series (159 TCs, 5 TPs), Biodiversity and Conservation (152 TCs, 2 TPs), Ciencias Marinas (115 TCs, 1 TP), and the Journal of Biogeography (103 TCs, 2 TPs). As per the publication record, Botanica Marina ranked first with 11 TPs, while Molecular Ecology and Ciencias Marinas ranked last with 1 TP each. According to the InCites Journal Citation Reports by Clarivate Analytics 2023 [29], Molecular Ecology, Frontiers in Marine Science, and the Journal of Biogeography were the top three journals, with impact factors of 4.5, 4.0, and 3.4, respectively.

3.2.5. Author Keyword Analysis

For the top keyword analysis, ‘seaweeds’ occurred (OC) 19 times with a total link strength (TLS) of 101, followed by the keywords ‘macroalgae’ (OC 14, TLS 69), ‘taxonomy’ (OC 9, TLS 55), ‘rbcL’ (OC 8, TLS 45), ‘biogeography’ (OC 8, TLS 39), ‘photosynthesis’ (OC 7, TLS 39), ‘phylogeography’ (OC 7, TLS 39), ‘Rhodophyta’ (OC 8, TLS 38), ‘Pheophyceae’ (OC 7, TLS 35), and ‘Antartica’ (OC 6, TLS 33) [Supplementary Figure S6].

3.3. Conservation of Seaweed

3.3.1. Most Active Countries in the Conservation of Seaweed—Global Scenario

The WoS platform of the topic-wise search for the conservation of seaweed recorded 107 articles published globally. Bibliometric analysis of the top 10 countries showed the global publication contribution for these countries ranged from 1.87% (Singapore) to 14.95% (USA) (Supplementary Table S12; Supplementary Figures S7 and S8). Among the top active countries, the USA ranked first based on 414 TCs of 16 TPs, followed by Australia (401 TCs, 13 TPs), Spain (337 TCs, 15 TPs), Japan (300 TCs, 14 TPs), Italy (226 TCs, 10 TPs), China (168 TCs, 8 TPs), Singapore (160 TCs, 2 TPs), Portugal (147 TCs, 5 TPs), and France (142 TCs, 11 TPs). The other prolific and influential countries, such as Brazil, Chile, Mexico, India, Canada, and Scotland, reported 5.61, 4.67, 4.67, 3.74, 3.74, and 3.74% of the total publications, respectively. Despite their relatively lower citation counts than the leading nations, these countries have significantly contributed to advancing the field.

The top active institutions representing their countries in terms of the research papers published between 1995 and 2023 are listed in Supplementary Table S13. Among these, the Consejo Superior De Investigaciones Cientificas CSIC, Spain, ranked first based on 262 total citations of 7 TPs, followed by the NSW Department of Primary Industries, Australia (206 TCs, 7 TPs), the Japan Fisheries Research Education Agency FRA, Japan (161 TCs, 4 TPs), Universitat De Girona, Spain (150 TCs, 4 TPs), Csic Centre D’Estudis Avancats De Blanes CEAB, Spain (148 TCs, 4 TPs), the University of Oxford, England (143 TCs, 4 TPs), the University of Barcelona (139 TCs, 5 TPs), Centre National De La Recherche Scientifique CNRS, France (127 TCs, 9 TPs), the Chinese Academy of Sciences, China (123 TCs, 4 TPs), and Northeastern University, USA (114 TCs, 2 TPs).

The top funding agencies representing their countries who funded research on the conservation of seaweed are listed in Supplementary Table S13. Among them, the European Union (EU) secured the first position based on 296 TCs of 9 TPs, followed by the European Commission, France (248 TCs, 7 TPs), the Australian Research Council, Australia (170 TCs, 3 TPs), Horizon 2020 (145 TCs, 3 TPs), Generalitat De Catalunya, Spain (128 TCs, 4 TPs), the National Science Foundation NSF, USA (108 TCs, 2 TPs), the Spanish Government (79 TCs, 3 TPs), the Japan Society for the Promotion of Science, Japan (77 TCs, 3 TPs), the Ministry of Education, Culture, Sports, Science, and Technology, Japan (77 TCs, 3 TPs), and the National Natural Science Foundation of China NSFC, China (59 TCs, 3 TPs).

3.3.2. Year-Wise Distribution of Publications

The year-wise distribution of publications on the conservation of seaweed from 1995 to 2023 is listed in Supplementary Table S14 and Figure S9. In 2020, researchers recorded the maximum of 17 TPs corresponding to 330 TCs, followed by 16 TPs in 2021 with 231 TCs and 11 TPs in 2019 with 217 TCs. The quality assessment of the countries in terms of the average citations per paper (ACCP) revealed that ACCP ranged from 2 (2023) to 66 (2003). The overall average number of publications per year (APPY) was 3.95. Note that 2020 contributed the highest number of citations, at 330 with 17 ACPP, while 2000 and 2006 ranked last in the citation list with 4 TCs and 4 ACPP each.

3.3.3. Citation Analysis of the Top Publications and Authors

The highly cited publications in the conservation of seaweed research are listed in Supplementary Table S15. The most cited publication was “Towards Restoration of Missing Underwater Forests” with 123 TCs. In contrast, the least cited publication was “Management-free techniques for restoration of Eisenia and Ecklonia beds along the central Pacific coast of Japan” with 44 TCs. As shown in Supplementary Table S16 and Supplementary Figure S10, author M.A. Coleman secured the top in the list with 206 TCs of 7 TPs, while B. Hereu ranked last with 111 TCs of 4 TPs. The top highly cited research publications related to seaweed conservation focus on realistic losses of rare species [40], bio-protection and restoration of underwater forests [41,42,43,44,45], hard coastal defense structures as habitats for native and exotic species [46], the application of remote sensing data to monitor coastal vegetation [47], blue carbon strategies [48], and biogeographic classification and conservation planning [49].

3.3.4. Top Productive Journals

The top journals on conservation of seaweed research are listed in Supplementary Table S17 and Supplementary Figure S11. Ocean Coastal Management ranked first based on 143 TCs of 7 TPs, followed by Marine Environmental Research (137 TCs, 3 TPs), Plos One (123 TCs, 1 TP), Ecology Letters (107 TCs, 1 TP), Frontiers in Marine Science (86 TCs, 11 TPs), the Journal of Applied Phycology (86 TCs, 5 TPs), Frontiers in Plant Science (84 TCs, 1 TP), Geomorphology (78 TCs, 1 TP), Conservation Biology (77 TCs, 2 TPs), and the Indian Journal of Marine Sciences (71 TCs, 1 TP). As per the publication record, Frontiers in Marine Science ranked first with 11 TPs, while PloS One, Ecology Letters, Frontiers in Plant Science, Geomorphology, and the Indian Journal of Marine Sciences ranked last with 1 TP each. According to the InCites Journal Citation Reports by Clarivate Analytics 2023 [29], Ecology Letters, Conservation Biology, and Frontiers In Plant Science were the top three journals with impact factors of 7.6, 5.8, and 5.6, respectively.

3.3.5. Author Keyword Analysis

Among the top author keyword analysis, ‘seaweeds’ occurred (OC) 24 times with a total link strength (TLS) of 142, followed by ‘conservation’ (OC 17, TLS 98), ‘macroalgae’ (OC 12, TLS 66), ‘climate change’ (OC 8, TLS 48), ‘restoration’ (OC 7, TLS 39), ‘marine conservation’ (OC 8, TLS 38), ‘kelp’ (OC 4, TLS 36), ‘biodiversity’ (OC 7, TLS 35). ‘genetic diversity’ (OC 4, TLS 35), and ‘algae’ (OC 5, TLS 34) [Supplementary Figure S12].

3.4. Extensively Studied Seaweed Species Across Various Countries for Seaweed Biodiversity Research, Endemism, and Conservation Efforts

In the areas of seaweed biodiversity, endemic seaweed, and the conservation of seaweed, the widely studied seaweed species are depicted in Supplementary Tables S18–S20, respectively. Among the top countries in seaweed biodiversity, Australia has focused extensively on species such as Ecklonia radiata, Sargassum spp., and Caulerpa taxifolia. The USA has concentrated its research on species like Gracilaria vermiculophylla, Macrocystis pyrifera, and Saccharina latissima. Researchers in England have paid significant attention to species such as Undaria pinnatifida, Fucus serratus, Sargassum muticum, and Asparagopsis armata. These studies aim to comprehensively explore the biodiversity, ecological significance, and challenges posed by invasive species of seaweeds, with a strong emphasis on understanding their ecological roles, environmental impacts, and potential economic benefits, while also exploring their applications in biotechnology and conservation (Supplementary Table S18).

In endemic seaweed research, among the top countries, Germany has extensively focused on species such as Ascoseira mirabilis, Desmarestia anceps, Palmaria decipiens, and Laminaria solidungula. The USA has concentrated its research on species like Griffithsia aestivana, Laminaria solidungula, and Pelvetiopsis californica. In Australia, researchers have directed their efforts towards species such as Chamaedoris peniculum and Cystophora spp. The studies aim to comprehend the unique ecological roles of seaweed species, their adaptability to local conditions, and their ecological contributions, while addressing the challenges posed by invasive species in marine environments (Supplementary Table S19).

In the area of seaweed conservation, among the top countries, the USA focused on seaweed species such as Laminaria abyssalis, Kappaphycus alvarezii, Eucheuma denticulatum, Porphyra umbilicalis, and Pyropia yezoensis. Australia has concentrated its research on species like Nereia lophocladia, Ecklonia radiata, Hormosira banksii, and Phyllospora comosa. In Spain, extensively studied seaweed species include Cystoseira zosteroides, Ahnfeltiopsis pusilla, Phymatolithon calcareum, Grateloupia lanceola, and Cystoseira abies-marina. These efforts highlight the critical ecological roles of seaweeds in marine ecosystems, underscore the urgency of conservation efforts to safeguard their biodiversity against environmental threats, and emphasize their essential contributions to aquatic ecosystems and the imperative need for preservation (Supplementary Table S20).

3.5. Drivers of Biodiversity Loss

In our analysis of all three topics (966 TPs), we found seven major drivers and four emerging drivers of biodiversity loss (

Table 4. Drivers of biodiversity loss included in this study.

Drivers	Ecological Outcomes	References
Main drivers
Climate Change	Changes in biological and physical community, precipitation frequency and intensity, ocean acidification, rise in water temperature, and fluctuations in wind pattern and in hydrology	[16,17,50,51]
Pollution	Affects the water quality in coastal and estuarine habitats through nutrients and toxins	[16,50]
Unsustainable exploitation	Exploitation of natural resources and incautious development practices threaten the health of the ecosystem	[17]
Invasive species	Risk for local biodiversity and ecosystem functioning; replaces slow-growing species with faster growth rate and nutrient uptake. Responsible for anoxic events; massive mortalities of epifauna and infauna	[52]
Habitat Degradation	Biodiversity loss, productivity decline; altered habitat composition	[53,54]
Anthropogenic impact	Human-induced changes in hydraulic conditions, exploration, and extraction of oil or gas affect regions	[15]
	Increasing development and mining activity cause the deterioration in coastal and marine environments	[17]
Introduced Species	Space monopolization; reduces the abundance of native macrophytes	[55]
	Facilitates associated non-indigenous organisms	[56]
Emerging drivers
Outdoor activities (Fishing, sports, harvesting aquatic resources)	Threaten marine protected areas	[15]
Tourism	Risks of potential invasions	[16]
Deforestation and coastal development	Causes an increase in turbidity and sedimentation runoff, reclamation of shallow coastal habitats that smother seagrass beds	[17]
Diseases and epiphytism	Disease outbreaks cause decline and die-off of seaweeds	[18]

), all representing 22.20% (TP 262) of the total number of articles. Out of the 262 articles identified, climate change was the most researched driver, contributing 45.80% with 120 articles. Invasive species was the second most researched topic, contributing to 34.73% with 91 articles. Anthropic impact contributed 8.02% with 21 articles. Drivers, namely pollution, contributed 4.96% with 13 articles, followed by introduced species, habitat degradation, and unsustainable exploitation, which contributed 4.20%, 1.53%, and 0.76% with 11, 4, and 2 articles, respectively.

4. Discussion

Seaweed research has increased recently because of its sustainability and its environmentally friendly bio-products. We reported a scientometric analysis of 966 publications from 253 journals on seaweed biodiversity, endemic seaweed, and conservation of seaweed. Analyzing and evaluating the scholarly literature from these domains align with recent global initiatives to provide objective data that reflect the significance of research to scholars and organizations. Various scientometric analyses were carried out globally for seaweed (algal) research. Konur reported 36,050 papers published related to algal structures [57]. Scientometric analysis of overall seaweed research showed that, globally, 5814 publications were published in 1419 journals from 2005 to 2014 [58]. Mohan and Ravi reported 405 publication records from 1981 to 1987 and 3125 publications from 1988 to 1996 [59]. Further, 505 and 521 records were published from 1994 to 2019 and 1985 to 2019 in the WoS and Scopus databases, respectively, in seaweed for biofuels [60]. Steady growth was observed in global biodiversity research during 1980–1999 and peaked during 2000–2009 [61]. This study focused on subject categories such as ecology, environmental sciences, biodiversity conservation, and plant science.

Our analysis revealed empirical evidence that focused research in seaweed biodiversity, endemism, and conservation began in the 1990s. This analysis coincides with the 1992 United Nations Conference on Environment and Development (UNCED), also known as the Rio Earth Summit [62]. In this Summit, 150 government leaders signed the Convention on Biological Diversity with three objectives: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of benefits from using genetic resources. Such a global initiative has enabled seaweed scientists to take biodiversity conservation from regional to national and international levels. In the present study, the growth in publications between 1992 and 2023 in seaweed biodiversity research was not constant. There were fluctuations in the publication rates over time. Still, there was a significant rise in publications after 2010. Similarly, in endemic seaweed research (1994–2023) and conservation of seaweed research (1995–2023), a significant rise in publications was observed after 2015 and 2018, respectively. Similarly, scientometric analysis of algal structures reported steady growth from 2010 to 2018 [57]. This trend coincides with the initiative of the Strategic Plan for Biodiversity adopted by Parties to the Convention on Biological Diversity between 2011 and 2020. By 2050, the goal is for biodiversity to be valued, conserved, restored, and utilized wisely, thereby preserving ecosystem services, ensuring a healthy planet, and providing essential benefits for all people.

In the present investigation, 84 countries and territories contributed to seaweed biodiversity research, 49 contributed to endemic seaweed research, and 50 contributed to the conservation of seaweed. In seaweed biodiversity research, Australia secured the first position based on the total citations (7559), followed by the USA, England, Spain, France, Italy, Portugal, Wales, North Ireland, and New Zealand. Beyond these top-performing nations, several other prolific and influential countries, including Brazil, Canada, Japan, Germany, Ireland, China, Mexico, Norway, Greece, and Chile, have made notable contributions to this field. Although their citations and publication records are comparatively lower, these countries have made meaningful advancements in specialized areas such as marine freshwater biology, plant sciences, biodiversity conservation, environmental sciences, and ecology. In endemic seaweed research, Germany ranked first based on the total citations (645), followed by the USA, Australia, France, The Netherlands, New Zealand, Portugal, Brazil, Canada, and Spain. Similarly, other influential countries have significantly contributed to this area, including Chile, Italy, South Korea, Sweden, China, Japan, England, Belgium, Mexico, and Israel. While their citation and publication metrics are relatively modest, they have excelled in research domains such as marine freshwater biology, plant sciences, biodiversity conservation, and ecology.

Meanwhile, in the conservation of seaweed research, the USA ranked first with 414 TCs, followed by Australia, Spain, Japan, Italy, China, Singapore, Portugal, and France. Countries like Brazil, Chile, Mexico, India, Canada, and Scotland have contributed notably to this field. Despite comparatively lower citation and publication records, these nations have contributed meaningfully to marine freshwater biology, oceanography, biodiversity conservation, and ecology. This analysis highlights the growing diversity in global research contributions and emphasizes the importance of fostering international collaboration to bridge the gap between leading and emerging contributors in studies on seaweed biodiversity, endemic seaweeds, and conservation.

Similarly, a study of algal structures reported that 150 countries and territories contributed to the area of algal structures research [57]. The United States showed significant contributions, followed by Canada, Australia, Japan, and Europe. Reports indicate that 106 countries contributed to overall seaweed research, with the USA securing the first position through significant contributions, followed by China, South Korea, Japan, Brazil, Spain, India, the UK, France, and Canada [58]. The mapping of seaweed research showed that 86 countries contributed to this domain; among them, the USA contributed the highest number of publications, followed by Japan, China, India, France, Chile, Canada, the UK, and Spain [59]. In biofuel research, China and South Korea were the most influential countries and ranked at the top [60]. Yet another study showed the USA in first position in the domain of global biodiversity research [61]. The USA leads in seaweed research; this might be because they have a well-developed research infrastructure, including universities, research institutions, and funding agencies. This primarily supports the development of cutting-edge technologies and innovative ideas in various fields, including seaweed. The USA has diverse coastal habitats supporting rich species diversity, making it an ideal location for studying and researching the biology, ecology, and conservation of seaweed. This enables research opportunities under a broader range of topics, from molecular to ecosystem-level studies. These factors and prevailing expertise might have made the USA a top country in seaweed research under the investigated domains. The Chinese government implemented its flagship Renewable Energy Law in 2006 to promote the development and utilization of renewable energy and executed a subsidy program for ethanol production. Further, in 2010, the government also granted 22 national energy research centers to promote the energy sector and integrated efforts between research and industry [63]. This might have enhanced the publication trend in China and South Korea toward research for seaweed biofuels.

At the institution level, the present study showed that the University of Western Australia, Australia, ranked first based on 3688 total citations of 40 publications in seaweed biodiversity research. The Alfred Wegener Institute Helmholtz Centre for Polar Marine Research, Germany, ranked first, based on 533 TCs of 17 TPs in endemic seaweed research. Consejo Superior De Investigaciones Cientificas CSIC, Spain, ranked first with 262 TCs of 7 TPs in conservation of seaweed research. Meanwhile, the Chinese Academy of Sciences ranked first in global biodiversity research [61]. In seaweed biodiversity research, the Journal of Experimental Marine Biology and Ecology, Ecology, and Botanica Marina were the top three journals based on the citation records.

Regarding endemic seaweed research, Botanica Marina, the European Journal of Phycology, and the Journal of Phycology were the top journals based on the citation records. In conservation of seaweed research, Ocean Coastal Management, Marine Environmental Research, and Plos One contributed the most, based on the citation records. In contrast, in global biodiversity research, Biological Conservation, the Journal of Soil and Water Conservation, Conservation Biology, and Biodiversity and Conservation published the most articles [61]. Similarly, scientometric analysis of seaweed research reported that the Journal of Applied Phycology, the Journal of Phycology, and Botanica Marina were the top journals with significant contributions [58]. Mohan and Ravi reported that Botanica Marina has made substantial contributions to the mapping of seaweed research [59]. At the same time, the Journal of Applied Phycology and the Journal of Phycology were the top influential journals in their mapping study of global seaweed research.

Among the top publications, highly cited research in seaweed biodiversity was in the domain of geographical distribution, a global marine environmental dataset (GMED) for marine ecosystems, and global warming research. Among these, geographical distributions and a global environmental dataset for marine ecosystems have recently gained importance [21]. Given this, it is worth mentioning that the research findings emanated from species distribution models (SDMs) have significantly impacted our understanding of future landscapes, based on known and projected environmental parameters [64]. Further, the global marine environment dataset (GMED) is a compilation of publicly available climatic, biological, and geophysical environmental layers featuring present, past, and future environmental conditions [65]. The GMED covers the broadest range of environmental layers, including the depth profile. The uniform spatial extent, high-resolution special land mask eliminating land areas from the marine regions, and ease of search from free public online databases help in a quick map overlay of species of interest encompassing various environmental parameters of the past, present, and future [65]. The ease of expediting the distribution mapping of species of interest using easily accessible species distribution algorithms might have made this tool popular for seaweed studies.

Similarly, in endemic seaweed research, the top highly cited research publications were in the domain of biogeographical studies, environmental and ecological impacts, population dynamics, and hybridization. The biogeographical studies provide a comprehensive understanding of the distribution, diversity, and evolution of life on Earth and are essential for addressing challenges related to biodiversity conservation and sustainable development. Environmental and ecological impact studies play a critical role in understanding the potential impacts of human activities on the natural environment and ecosystems, and they provide essential information for informed decision-making in environmental planning, conservation, and sustainable development [66]. Nevertheless, the top highly cited research publications in the conservation of seaweed research were in the domain of realistic losses of rare species, bioprotection and restoration, and the application of remote sensing data monitoring. The study of realistic losses of rare species is vital for understanding the impact of species loss on biodiversity, ecosystem function, climate change adaptation, economic value, genetic diversity, and designing effective conservation strategies [40]. The bioprotection and restoration of seaweed are essential for conserving biodiversity, maintaining ecosystem function, promoting climate change adaptation, supporting economic benefits, and protecting coastal areas.

In the present study, T. Wernberg, C. Wiencke, and M.A. Coleman were the most productive authors, based on the total citations in seaweed biodiversity, endemic seaweed, and conservation of seaweed research, respectively. Global biodiversity research [61] showed that Gaston and Nevo were the most productive authors, whereas Y.J. Jeon, [58], and G.C. Trono, Jr. [59] were the top authors, respectively, in overall seaweed research in the respective studies. The study suggested substantial research funding opportunities in China compared to the United States and Europe [57]. The present investigation supported the idea that funding opportunities are varied, and that maximum funding is available in the United States. The subject category analysis revealed the top five fields driving scientific research in global seaweed biodiversity. These categories include marine freshwater biology, ecology, plant sciences, environmental sciences, and oceanography. Similarly, in endemic seaweed research, the key categories were marine freshwater biology, plant sciences, ecology, biotechnology, applied microbiology, and oceanography. In the domain of seaweed conservation research, the predominant categories identified were marine freshwater biology, environmental sciences, ecology, water resources, and biodiversity conservation. As per Konur’s subject category data analysis, marine freshwater biology, plant sciences, biochemistry, molecular biology, cell biology, and oceanography were the five key categories in algal structure research [57]. Similarly, mapping of seaweed research reported that seaweed culture, seaweed production, seaweed resources, seaweed exploitation, and seaweed industry were the top subject categories [59].

Identifying drivers of biodiversity loss (Table 4) is crucial for developing sustainable ecosystem management to help conserve seaweed biodiversity. We found the seven major direct drivers that unequivocally impact biodiversity and ecosystem processes. Nevertheless, four emerging drivers were significant indirect drivers, stemming from the direct drivers. The major drivers tend to change the ecosystem at an imminent level, likely involving interactions with other major drivers, thereby feeding back into indirect drivers. The analysis of the drivers responsible for biodiversity loss revealed that research endeavors are disproportionate among different drivers. Developing countries are expected to exert greater pressure on marine ecosystems, as these areas serve as harbingers of economic growth [67]. Thus, determining the drivers affecting biodiversity in these nations is extremely necessary. Overlooking research in developing countries would hinder effective conservation and mitigation attempts and likely circumscribe our progress in the overall comprehension of biodiversity loss.

A bibliometric analysis between 2010 and 2019 reported that 20% of the research articles on the freshwater biodiversity domain addressed drivers of biodiversity loss [68]. Although direct comparison is not possible due to the different time scales used for the bibliometric analysis, having 32.71% of the research articles on the seaweed biodiversity domain reported in the present investigation seems to be better. In another investigation, among all the drivers studied across terrestrial, marine, and freshwater systems, ‘climate change’ was the most researched driver, representing 40.3% of the published articles [69]. Our study also corroborated this observation, with ‘climate change’ remaining the most researched driver in the global bibliometric analysis of seaweed biodiversity, endemism, and conservation taxa, at 45.80%. ‘Climate change’ acts as a high-profile global issue. However, in the present investigation, we found that research on climate change, seaweed biodiversity, endemic seaweed, and conservation of seaweed is relatively limited, with only 120 publications addressing these topics, despite the magnitude of the problem.

Climate-determined changes in coastal habitats include key features that influence the composition of marine vegetation and the biodiversity of the coastal ecosystem. Overlying kelp canopies shifting in response to ocean warming have influenced the structure and diversity of seaweed assemblages [70,71]. A rise in ocean warming caused the potential decline of unique biodiversity in Arctic marine forests and ecosystem elasticity in Arctic coastal habitats due to the dramatic loss of perennial ice cover [72]. An increase in surface seawater temperature caused a productivity decrease in two cultivable species, namely Eucheuma and Kappaphycus, and this was identified as the large challenge facing the seaweed industry in Tanzania [18]. Climate change also has indirect effects by impairing other human pressures, i.e., the rise in several dams and other hydraulic structures in response to the upsurge frequency of floods and droughts [68]. Invasive species affect ecosystem functioning by replacing the slow-growing species in their natural habitat, slowing down nutrient recycling, and enhancing the high biomass densities of fast-growing species.

Further, these changes culminate in summer anoxic events and threats to local biodiversity [52]. Anthropic threats such as fishing and harvesting aquatic resources, alterations in hydraulic conditions due to human interventions, and oil or gas exploration and extraction have been reported and have been found to impact marine protected areas (MPAs) [15]. Increasing fisheries’ development, sea mining activity, illegal enterprise, and poorly planned coastal development cause the deterioration of coastal habitats [17]. Changes in precipitation patterns, ocean acidification, a rise in water temperature, and fluctuations in wind patterns and hydrology, combined with anthropogenic pollution cause changes in water quality in estuarine and coastal waters [16,50]. Space monopolization by introduced species diminishes the abundance of native macrophytes in their natural habitat [55]. Habitat degradation also causes biodiversity loss, alters habitat composition, and is ultimately responsible for the decline in productivity of particular areas [53,54]. Unsustainable exploitation of natural resources and incautious development practices threaten ecosystem health [17]. Their establishment also facilitates the proliferation of associated non-indigenous organisms [56]. Some emerging drivers like outdoor activities, tourism, deforestation and coastal development, disease, and epiphytism also affected the health of the marine ecosystem.

Outdoor activities like fishing, sports, and aquatic resource utilization threaten marine protected areas (MPAs) [15]. Tourism causes the risk of the potential invasion of non-indigenous species [16]. Deforestation and coastal development cause an increase in turbidity and sedimentation runoff reclamation of shallow coastal habitats that smother seagrass beds [17]. Disease outbreaks cause the decline and die-off of seaweed beds. The main effects of high temperatures on seaweeds are the infestation of ice–ice disease (whitening of the thallus) and epiphytism, which were reported by several studies worldwide [73,74,75]. Some of these adverse effects were mitigated through the project ‘Operation Crayweed’, in which researchers worked on restoring and re-introducing kelp forests along the Sydney coastline [76]. Additionally, they were involved in raising awareness about the status of underwater kelp forests, which are at risk and facing global decline.

Working in collaboration and having sufficient funding are the key determinants for biodiversity research. The successful authors (highly cited) outperformed because they collaborated with other researchers with complementary and different skill sets to make a significant impact. Sharing financial resources allowed them to implement large projects, hire talent, and share discoveries widely. The way institutions and organizations support and encourage fundamental research also plays a big part in seaweed biodiversity studies. However, some ranking systems may favor established names over newer voices, highlighting the need for fair evaluation methods to ensure everyone has an equal opportunity to succeed. Relying solely on English-language sources creates a bias because it excludes essential research and information. This approach overlooks valuable contributions from non-English speaking regions, leading to an incomplete representation of literature productivity, active countries, influential authors, highly cited publications, and research trends. Non-English research often includes unique insights and methods and indigenous knowledge documented in local languages. Therefore, future analyses should use multilingual databases, collaborate with diverse linguistic researchers, and seek out non-English publications to comprehensively understand seaweed biodiversity, endemism, and its conservation. However, such an analysis was outside the scope of the present investigation.

5. Scientific Opinions

• Countries: Inter-institutional collaborations were more prevalent than international collaborations. Moreover, collaborative works drew more citations than single-country or single-institution publications [61]. The scientific outputs were related to economic developments, as fully developed and fast-developing countries were among the productive countries. Countries with broad coastal areas need awareness through academic institutions in the research field to conserve coastal habitats. Developed countries should support countries with less productivity in the scientific field, which will trigger countries’ research productivity. Scientometrics studies are required to understand the country’s current position or productivity at the global level.
• Journals: Several regional institutions are introducing journals of their own. These journals publish good papers, but their works do not have a wider readership [77]. The core journals should accept multidisciplinary subject papers in their journals. Further, journals should accept publications in narrow and broader subject areas that can help increase the readership. The publishing houses should take the initiative to make publications available to users through open-access platforms and should start subject-specific repositories. Creating a worldwide database of authors’ contributions on a single portal will help end users avoid the chaos of several scientific search platforms, namely Google Scholar, ResearchGate, Web of Science, Scopus, etc.
• Author: The type of collaboration can help estimate the author’s productivity through subcategories like mentoring given, mentoring received through collaboration with colleagues, and collaboration as feedback during the writing process [78]. Awareness is necessary for graduate students to increase their contribution to research. College/university mentors can encourage graduate students to participate and present their work in national and international conferences and workshops for knowledge sharing; this might increase author contribution. Displaying the top author’s contributions at the designated journal repositories can improve the author’s productivity. There is a need to encourage the research community to contribute their research findings in local scientific journals to overcome the language barrier; this will lead to increased authorship as well as the productivity of journals. As conventionally considered, fewer citations cannot be the criterion for an author’s productivity due to emerging fields or less focused research areas.
• Organizational productivity: Organizational variables like freedom in work can influence or increase publication productivity in the research field. Organizational focus on a particular field can influence publication productivity. This directly relates to the thought process and convictions shaped by leadership, which may prioritize specific outputs, such as patents, reports, or documents, over traditional publications.
• Funding agencies: Increased funds, facilities, and recognition for research may be especially essential for those scientists of high potential who cannot obtain funding as easily [79]. National funding agencies and much tacit knowledge strongly influence interdisciplinary research programs and projects. Thus, funding agencies have critical roles, especially in shaping large-scale interdisciplinary initiatives [80]. The funding agencies should collaborate with journals or publishers to promote the author’s contributions in research areas and support open access.

6. Recommendations

The first Convention on Biological Diversity highlighted and introduced a central concern about biodiversity and the consequences of its destruction to the global forum. Yet the focal point of any such global initiatives often only considers a small subset of species (primarily terrestrial with few exceptions of marine), while seaweed biodiversity remains ignored. The present study unequivocally demonstrated a research gap in seaweed biodiversity, conservation of seaweed, and endemic seaweed. We recommend that a number of Special Issues and special sections of journals be required to encourage research in the above topics especially phycological journals of reputed societies, namely, the Journal of Phycology (Phycological Society of America); Phycologia (International Phycological Society); the European Journal of Phycology and Applied Phycology (British Phycological Society); Phycological Research (Japanese Society of Phycology); and Algae (Korean Society of Phycology). The editors of these journals could take special interest and assist in connecting authors from developing countries with well-established research groups for preparing compelling manuscripts before submission, thus increasing the chances of publication on the above topics. The multisector collaborations and partnership of the international research community at the global level are necessary to contribute to these research areas that can effectively address global biodiversity loss. Experts have identified the lack of adequate funding for seaweed taxonomy projects as the major factor impacting this research domain. We need a return-on-investment perspective for rigorous taxonomic research on seaweeds, prioritizing evaluations of benefits against costs. Such an initiative might help solve this issue, as proposed by other groups, e.g., the Australian squamate [81]. The training, capacity building, and recruiting of new seaweed taxonomists is becoming increasingly difficult, since, globally, university education faces a considerable reduction in courses offering specialized curricula in this domain. Further, a change in priorities in research institutions at the national and international levels exacerbates the situation. More focused attention and policy interventions in succession planning, skilling of existing human resources, and fresh recruitment to permanent positions might help. Globally, initiatives like the Blue Growth Initiative (BGI), a flagship program by the Food and Agriculture Organization (FAO), are needed to support sustainable fisheries and aquaculture sectors by improving the governance and management of the aquatic ecosystems, conserving biodiversity and habitats, and empowering communities [82].

7. Conclusions

Given the increasing public importance of seaweeds as a marine sustainable resource for commodity applications, research on seaweed biodiversity, indigenous taxa, and their conservation assume pivotal significance. The detailed bibliometric analysis presented in the current investigation would be helpful to different stakeholders in devising optimal development of the research prospects in this field with comparatively low funding opportunities. However, investigations on seaweed biodiversity are relatively well planned and investigated nationally and internationally. At the same time, research on endemic seaweed and conservation of seaweed has registered a limited number of authors, academic institutions, and countries, enabling the latter two domains to have the first-mover advantage. The precise identification of drivers of biodiversity loss of seaweeds could be helpful for developing sustainable ecosystem management and conservation strategies. We prophesy that in the genomics era, seaweed biodiversity will obtain much-needed attention in drawing coherent conservation plans and inventive bioprospecting strategies that benefit humankind.