Seagrass: The Forgotten Ocean Treasure
Global Research Trends Revealed
They are not seaweed, but the only flowering plants that grow completely submerged in seawater, silently guarding our coastlines.
In the blue ocean, there are unsung "guardians" - seagrasses. These flowering plants completely submerged in seawater form seagrass bed ecosystems with their surrounding environment, which together with mangroves and coral reefs are called the three typical coastal marine ecosystems 1 3 .
Although seagrass beds maintain the ecological environment of coastal waters and the safety of marine fishery resources, the number of seagrass species and the area of seagrass beds are decreasing sharply worldwide, and their survival is facing severe challenges 5 .
Compared with coral reefs and mangroves, these "underwater grasslands" receive much less attention. Scientists have used bibliometrics as a scientific "telescope" to review the development trajectory of international seagrass research over the past 35 years, revealing the research landscape of this hidden world 1 .
What is Seagrass? The Invisible Guardian of the Ocean
Seagrasses are large submerged higher plants that grow in shallow seas and estuarine areas. As the only monocotyledonous angiosperms that can complete their entire life cycle (flowering, fruiting, and germination) in seawater, they play an irreplaceable role in marine ecology 5 .
Global seagrasses are distributed in 9 major flora, including the temperate North Atlantic flora, temperate South Atlantic flora, Mediterranean flora, and Indo-Pacific flora 5 .
These "underwater grasslands" form seagrass beds that are among the most productive aquatic ecosystems in the biosphere. Each square meter of seagrass can produce large amounts of organic matter through photosynthesis, becoming the foundation of marine food webs 5 .
Seagrass beds have diverse and critical ecological service functions: they can purify water quality by absorbing excess nutrients; provide habitats for fish, shellfish, and other organisms to reproduce and shelter; and participate in ecosystem nutrient cycling, maintaining the ecological environment of coastal waters and the safety of marine fishery resources 1 .
However, because seagrasses have not been directly related to human life for a long time, research and protection of seagrasses have been relatively insufficient. Now, under the dual influence of human activities and natural factors, global seagrass beds face serious threats 5 .
Global Seagrass Research Trends: The Evolution Trajectory Revealed by Literature
Bibliometrics analyzes the external characteristics of literature and uses mathematical and statistical methods for quantitative analysis, which can objectively reflect the research status and development trends in a field 5 .
By analyzing seagrass research-related literature collected in the SCI-E database of Web of Science from 1983 to 2017, scientists found that the number of international seagrass research documents showed an obvious upward trend overall 1 3 .
According to the annual publication volume changes, seagrass research can be divided into two stages: 1983-1990 was the first stage, with fewer documents and no obvious growth; 1991-2017 was the second stage, with a significant increase in the number of publications 5 .
From 1983 to 2017, the average annual growth rate of seagrass research literature reached 9.21%, especially after 1991, the number of papers increased significantly. This growth trend is closely related to the accelerated degradation of global seagrass beds that has attracted the attention of scholars worldwide 5 .
| Time Period | Average Annual Publications | Growth Characteristics | Important Driving Events |
|---|---|---|---|
| 1983-1990 | Low | No obvious growth | Research just starting |
| 1991-2000 | Gradually increasing | Steady growth | Global seagrass degradation issues attracting attention |
| 2001-2010 | Significantly improved | Rapid growth | Increase in international marine protection initiatives |
| 2011-2017 | High and stable | Moderate growth | Many countries strengthening marine ecosystem research |
Distribution of Research Power: Contribution Map of Countries and Institutions
The field of seagrass research shows obvious country concentration characteristics. The top three countries in terms of publication volume are the United States, Australia, and Spain 1 .
[Interactive map visualization of global seagrass research contributions would appear here]
The number of publications in the United States accounts for 33.84% of the global total, 1.82 times that of Australia and 3.26 times that of Spain, showing the absolute dominant position of the United States in this field 5 .
At the institutional level, Florida State University ranks first in the world with 580 publications, accounting for 6.33% of the total literature. It is followed by the Spanish National Research Council (CSIC) and the U.S. National Oceanic and Atmospheric Administration (NOAA) 1 5 .
| Rank | Country | Publication Share | Research Institution | Total Publications |
|---|---|---|---|---|
| 1 | United States | 33.84% | Florida State University | 580 |
| 2 | Australia | 18.62% | Spanish National Research Council | Not specifically listed |
| 3 | Spain | 10.38% | U.S. National Oceanic and Atmospheric Administration | Not specifically listed |
| 4 | Italy | ~6% | University of Western Australia | Not specifically listed |
| 5 | France | ~6% | French National Centre for Scientific Research | Not specifically listed |
At the scientist level, Professor Duarte CM from King Abdullah University of Science and Technology in Saudi Arabia ranks first with 226 publications. Marbá N from the Spanish National Research Council and Fourqurean JW from Florida International University rank second and third respectively 5 .
These high-yield authors have formed a close cooperation network. Scholars such as Duarte CM and Marbà N have close academic cooperative relationships, and the four countries of Spain, Denmark, the Netherlands, and Mexico have also formed a closely related national cooperation network 1 .
Hot Research Topics: Three Focus Areas of Seagrass Science
Through the analysis of the association relationships of high-frequency keywords, the study reveals three hot topics in international seagrass research 3 :
Environmental Stress on Seagrass Beds
With coastal development and water pollution intensifying, scholars are focusing on the effects of environmental pressures such as nutrient enrichment, heavy metal pollution, and increased water turbidity on seagrass growth and distribution 5 .
Seagrass Growth and Physiological Ecology
Scientists are exploring basic biological issues such as the photosynthetic mechanism, nutrient absorption efficiency, and reproductive strategies of seagrasses to provide a theoretical basis for seagrass protection 1 .
Structure and Function of Seagrass Ecosystems
This research focuses on biodiversity, food web structure, energy flow and material cycling processes in seagrass beds, as well as the interactions between seagrass beds and adjacent ecosystems such as coral reefs and mangroves 3 .
In terms of academic journals, the journals that publish the most seagrass research are Marine Ecology Progress Series, Aquatic Botany and Estuarine, Coastal and Shelf Science. Among the top 15 journals in terms of publication volume, Limnology and Oceanography ranks first with an impact factor of 3.969 1 5 .
China's Seagrass Research: From Catching Up to Rising
China started relatively late in the field of seagrass research but has developed rapidly. As of the study period, China ranked 14th in the world with 242 publications, but the proportion of publications in the last three years was as high as 45.6%, surpassing all European and American developed countries 5 .
The Chinese Academy of Sciences ranks 44th in the world among research institutions with 100 publications and is the main force in China's seagrass research. Ocean University of China ranks 165th among global institutions with 31 publications and is also an important base for seagrass research in China 5 .
2017
The National Marine Administration issued the "13th Five-Year Plan for National Ecological Island and Reef Projects", proposing to implement the restoration of typical marine ecosystems such as coral reefs, mangroves, and seagrass beds, providing policy support for China's seagrass research 5 .
China's Seagrass Resources
- Existing seagrass bed area: ~87.65 km²
- Known seagrass species: 22
- Families, genera, and species numbers account for 66.7%, 83.3%, and 30.6% of the world's total respectively
- Main distribution areas: South China Sea and Yellow-Bohai Sea regions 5
Although Chinese scholars have shown rapid growth in the number of publications, the average citation frequency per paper (10.63 times/paper) is still lower than that of European and American developed countries, indicating that the influence of research results still has room for improvement 5 .
Scientist's Toolkit: Technical Equipment for Exploring Underwater Grasslands
Seagrass research relies on a series of advanced technical methods. Scientists use specific equipment and methods to overcome the challenges of underwater observation and experiments, revealing the mysteries of seagrass ecosystems.
Underwater Photosynthesis Measurement System
This professional equipment uses specially designed leaf chambers and sensors to directly measure the photosynthetic rate and respiratory rate of seagrasses underwater. Researchers use pulse amplitude modulation (PAM) fluorometers to measure chlorophyll fluorescence parameters and evaluate the photosynthetic efficiency and stress state of seagrasses 5 .
Sediment Sampling Drill
This specially designed drill is used to collect columnar sediment samples from seagrass beds. It can obtain undisturbed sediment columns while maintaining the complete stratification structure of the sediment. Scientists analyze sediments at different depths to reconstruct the historical changes and pollution accumulation processes of seagrass beds .
| Technical Category | Core Tools/Methods | Main Functions | Application Fields |
|---|---|---|---|
| Physiological Measurement | Underwater PAM fluorometer | Measure chlorophyll fluorescence parameters | Evaluate photosynthetic efficiency, environmental stress response |
| Ecological Survey | Side-scan sonar system | Large-scale mapping of seagrass distribution | Seagrass bed area assessment, long-term change monitoring |
| Sample Collection | Columnar sediment sampler | Obtain undisturbed sediment columns | Pollutant accumulation history reconstruction |
| Molecular Analysis | Stable isotope mass spectrometry | Measure stable isotope ratios of C, N, etc. | Food web structure, material cycling research |
| In Situ Observation | Underwater robot (ROV) | Conduct long-term underwater observation | Seagrass bed biological behavior, ecosystem process research |
Future Ocean: Opportunities and Challenges for China's Research
With the intensification of global climate change and the increasing pressure of coastal development, seagrass research faces new challenges and opportunities. Future research will pay more attention to the compound effects of climate change and multiple stresses, such as the interaction of ocean warming, acidification, and anthropogenic pollution on seagrass ecosystems 5 .
Future Research Directions
- Multifunctionality and ecosystem service assessment of seagrass ecosystems
- Seagrass bed restoration technology research and practice
- Strengthening international cooperation networks
- Improving research innovation and influence
- Conducting biological research on China's unique seagrass species
"With the advancement of national 'Ecological Civilization Construction' and 'Marine Power' strategies, seagrass research will receive more support. It is expected that in the near future, China is expected to become an important force in international seagrass research and provide Chinese wisdom for global marine ecosystem protection." 5
The fate of seagrass beds affects the health of the entire marine ecosystem. When we stand on the beach and look at the sea level, few people realize that the "green grassland" extending into the deep ocean under our feet is quietly disappearing.
From the perspective of bibliometrics, scientists' attention to these underwater grasslands is increasing. The rise of China's research power brings new hope for seagrass protection. The close cooperation network formed by Spain, Denmark, the Netherlands, and Mexico, and the high-yield performance of institutions such as the Chinese Academy of Sciences in recent years, all indicate that a global action to protect underwater grasslands is unfolding 1 .
In the next decade, as more countries join the ranks of seagrass research, this forgotten ocean treasure will finally regain human attention - not only existing in the literature libraries of scientists but also surviving in the blue ocean we all protect.