Seagrass Biology Research Articles

A Discussion on the Renaming of \(\textit{Cymodocea serrulata}\) to \(\textit{Oceana serrulata}\): Implications for Seagrass Research and Conservation in Vietnam

The seagrass species previously classified as Cymodocea serrulata has been reclassified as Oceana serrulata. This reclassification is based on genetic analysis, which reveals a distinct separation of this species from others within the Cymodocea genus. This change will have implications for future research and taxonomy, highlighting the value of advanced genetic techniques in elucidating the relationships between seagrass species. Nevertheless, further analysis is warranted as new evidence emerges. The transition to the designation Oceana serrulata harmonizes traditional morphological descriptions with modern genetic phylogenetics, enabling a more precise classification. This adjustment will facilitate targeted research on the newly categorized Oceana genus’s biology, ecology, and conservation. We emphasize the importance of disseminating this update to inform the scientific community about these alterations in species classification. Accurate taxonomy serves as the essential foundation for biological research and conservation efforts. Presenting the rationale and process behind taxonomic changes enhances understanding of scientists’ challenges. Furthermore, evaluating name changes encourages scientific discourse and feedback, underscoring the significance of ongoing taxonomic reassessment in advancing seagrass biology and conservation.

What’s new in marine botany of the Eastern Mediterranean?

Abstract This article provides a topical review of East Mediterranean phycology and seagrass biology, with a special focus on the outcomes of the multi-year project “Brown algal biodiversity and ecology in the Eastern Mediterranean Sea” supported by the TOTAL Foundation. Following a general overview of East Mediterranean seaweed biogeography and taxonomy, the review covers seagrasses, deep-water (circalittoral) macroalgal diversity, pathogens and algal defence, human impacts and biotic indices, alien species as well as the papers of this special issue.

Principles and concepts about seagrasses: Towards a sustainable future for seagrass ecosystems

Seagrasses grow in shallow marine and estuarine environments worldwide, providing multiple ecosystem services. However, a global trend of seagrass loss has been documented. Thus, increasing awareness of seagrass value is crucial for the sustainability of these vital ecosystems. This study aims to contribute to the creation of a seagrass-literate society, by defining key principles and concepts in relation to seagrasses that a seagrass-literate person should know. Six principles about seagrasses were defined. Each one is underpinned by a set of concepts. These principles and concepts concern key issues of seagrass biology (Principles 1-4), value (Principles 3-5), loss and protection (Principle 5), and research (Principle 6). Seagrass principles and concepts can be primarily used for educational purposes and as a practical resource to policy- and decision- makers. Our attempt could stimulate a collaborative effort of scientists and educators, aiming to improve the recommended principles and concepts, and to contribute to seagrass conservation.

Host-Specificity and Core Taxa of Seagrass Leaf Microbiome Identified Across Tissue Age and Geographical Regions

The seagrassZostera marinais a widespread foundational species in temperate coastal ecosystems that supports diverse communities of epiphytes and grazers. Bacteria link the production of seagrass to higher trophic levels and are thought to influence seagrass biology and health. Yet, we lack a clear understanding of the factors that structure the seagrass microbiome, or whether there is a consistent microbial community associated with seagrass that underpins functional roles. We sampled surface microbiome (epibiota) from new and old growth seagrass leaves and the surrounding seawater in eight meadows among four regions along the Central Coast of British Columbia, Canada to assess microbiome variability across space and as leaves age. We found that the seagrass leaf microbiome differs strongly from seawater. Microbial communities in new and old growth leaves are different from each other and from artificial seagrass leaves we deployed in one meadow. The microbiome on new leaves is less diverse and there is a small suite of core OTUs (operational taxonomic units) consistently present across regions. The overall microbial community for new leaves is more dispersed but with little regional differentiation, while the epiphytes on old leaves are regionally distinct. Many core OTUs on old leaves are commonly associated with marine biofilms. Together these observations suggest a stronger role for host filtering in new compared to old leaves, and a stronger influence of the environment and environmental colonization in old leaves. We found 11 core microbial taxa consistently present on old and new leaves and at very low relative abundance on artificial leaves and in the water column. These 11 taxa appear to be strongly associated withZ. marina. These core taxa may perform key functions important for the host such as detoxifying seagrass waste products, enhancing plant growth, and controlling epiphyte cover.

New Tools to Identify the Location of Seagrass Meadows: Marine Grazers as Habitat Indicators

Seagrasses are hugely valuable to human life, but the global extent of seagrass meadows remains unclear. As evidence of their value, a United Nations program exists (http://data.unep-wcmc.org/datasets/7) to try and assess their distribution and there has been a call from 122 scientists across 28 countries for more work to manage, protect and monitor seagrass meadows (http://www.bbc.com/news/science-environment-37606827). Emerging from the 12th International Seagrass Biology Workshop, held in October 2016 has been the view that grazing marine megafauna may play a useful role in helping to identify previously unknown seagrass habitats. Here we describe this concept, showing how detailed information on the distribution of both dugongs (Dugong dugon) and green sea turtles (Chelonia mydas) obtained, for example, by aerial surveys and satellite tracking, can reveal new information on the location of seagrass meadows. We show examples of how marine megaherbivores have been effective habitat indicators, revealing major, new, deep-water seagrass meadows and offering the potential for more informed estimates of seagrass extent in tropical and sub-tropical regions where current information is often lacking.

The Seagrass Holobiont and Its Microbiome.

Seagrass meadows are ecologically and economically important components of many coastal areas worldwide. Ecosystem services provided by seagrasses include reducing the number of microbial pathogens in the water, providing food, shelter and nurseries for many species, and decreasing the impact of waves on the shorelines. A global assessment reported that 29% of the known areal extent of seagrasses has disappeared since seagrass areas were initially recorded in 1879. Several factors such as direct and indirect human activity contribute to the demise of seagrasses. One of the main reasons for seagrass die-offs all over the world is increased sulfide concentrations in the sediment that result from the activity of sulfate-reducing prokaryotes, which perform the last step of the anaerobic food chain in marine sediments and reduce sulfate to H2S. Recent seagrass die-offs, e.g., in the Florida and Biscayne Bays, were caused by an increase in pore-water sulfide concentrations in the sediment, which were the combined result of unfavorable environmental conditions and the activities of various groups of heterotrophic bacteria in the sulfate-rich water-column and sediment that are stimulated through increased nutrient concentrations. Under normal circumstances, seagrasses are able to withstand low levels of sulfide, probably partly due to microbial symbionts, which detoxify sulfide by oxidizing it to sulfur or sulfate. Novel studies are beginning to give greater insights into the interactions of microbes and seagrasses, not only in the sulfur cycle. Here, we review the literature on the basic ecology and biology of seagrasses and focus on studies describing their microbiome.

Seagrass science is growing: A report on the 12th International Seagrass Biology Workshop

This conference report describes the programme of the 12th International Seagrass Biology Workshop, its highlights, areas of growth for the workshop, and potential future directions for the workshop series. The report is written with an eye toward where it fits within the field of seagrass research.

The emergence of molecular profiling and omics techniques in seagrass biology; furthering our understanding of seagrasses.

Seagrass meadows are disappearing at alarming rates as a result of increasing coastal development and climate change. The emergence of omics and molecular profiling techniques in seagrass research is timely, providing a new opportunity to address such global issues. Whilst these applications have transformed terrestrial plant research, they have only emerged in seagrass research within the past decade; In this time frame we have observed a significant increase in the number of publications in this nascent field, and as of this year the first genome of a seagrass species has been sequenced. In this review, we focus on the development of omics and molecular profiling and the utilization of molecular markers in the field of seagrass biology. We highlight the advances, merits and pitfalls associated with such technology, and importantly we identify and address the knowledge gaps, which to this day prevent us from understanding seagrasses in a holistic manner. By utilizing the powers of omics and molecular profiling technologies in integrated strategies, we will gain a better understanding of how these unique plants function at the molecular level and how they respond to on-going disturbance and climate change events.

Field data sets for seagrass biophysical properties for the Eastern Banks, Moreton Bay, Australia, 2004–2014

This paper describes seagrass species and percentage cover point-based field data sets derived from georeferenced photo transects. Annually or biannually over a ten year period (2004–2014) data sets were collected using 30–50 transects, 500–800 m in length distributed across a 142 km2 shallow, clear water seagrass habitat, the Eastern Banks, Moreton Bay, Australia. Each of the eight data sets include seagrass property information derived from approximately 3000 georeferenced, downward looking photographs captured at 2–4 m intervals along the transects. Photographs were manually interpreted to estimate seagrass species composition and percentage cover (Coral Point Count excel; CPCe). Understanding seagrass biology, ecology and dynamics for scientific and management purposes requires point-based data on species composition and cover. This data set, and the methods used to derive it are a globally unique example for seagrass ecological applications. It provides the basis for multiple further studies at this site, regional to global comparative studies, and, for the design of similar monitoring programs elsewhere.

Genome-wide survey of the seagrass Zostera muelleri suggests modification of the ethylene signalling network.

Seagrasses are flowering plants which grow fully submerged in the marine environment. They have evolved a range of adaptations to environmental challenges including light attenuation through water, the physical stress of wave action and tidal currents, high concentrations of salt, oxygen deficiency in marine sediment, and water-borne pollination. Although, seagrasses are a key stone species of the costal ecosystems, many questions regarding seagrass biology and evolution remain unanswered. Genome sequence data for the widespread Australian seagrass species Zostera muelleri were generated and the unassembled data were compared with the annotated genes of five sequenced plant species (Arabidopsis thaliana, Oryza sativa, Phoenix dactylifera, Musa acuminata, and Spirodela polyrhiza). Genes which are conserved between Z. muelleri and the five plant species were identified, together with genes that have been lost in Z. muelleri. The effect of gene loss on biological processes was assessed on the gene ontology classification level. Gene loss in Z. muelleri appears to influence some core biological processes such as ethylene biosynthesis. This study provides a foundation for further studies of seagrass evolution as well as the hormonal regulation of plant growth and development.

Twenty years of seagrass networking and advancing seagrass science: The International Seagrass Biology Workshop Series.

SEAGRASSES are a group of some 72 species of marine flowering plants found in the world’s shallow coastal oceans (Green and Short 2003, Short et al. 2011). There is now scientific consensus that they create an important marine habitat not only by themselves, but also as a component of more complex ecosystems within marine coastal zones. Seagrasses contribute to the health of coral reefs and mangroves, salt marshes and oyster reefs (Dorenbosch et al. 2004; Duke et al. 2007; Heck et al. 2008; Unsworth et al. 2008). Seagrasses have high primary productivity and are a basis of many marine food webs through direct herbivory and the through a detrital cycle (Hemminga and Duarte, 2000). They have enormous value in providing nutrients (N and P) and organic carbon to other parts of the oceans, including the deep sea, and they contribute significantly to carbon sequestration (Suchanek et al. 1985; Duarte et al. 2005). Armed with this knowledge today it is interesting to remember that it is only just over a hundred years since scientists first began speculating on the roles and values of seagrass in the marine environment, with the first focus occurring in Europe on eelgrass (Zostera marina). Many at the time discounted seagrass as an important primary producer (den Hartog 1980). It was not until after the 1930s, when vast areas of Zostera marina were lost in the northern hemisphere from a wasting disease that scientists and governments started to understand and investigate the value of seagrass to coastal ecosystems (Milne and Milne 1951). The loss of Zostera marina led to obvious declines in migratory waterfowl, crustaceans, finfish and shellfish populations (Thayer et al. 1984) In response to those concerns about ongoing losses of Zostera marina and other seagrass species, a meeting of scientists in Fairbanks, Alaska in early 1973 decided to coordinate seagrass research globally. This led to the first International Seagrass Workshop being organized and held in Leiden, The Netherlands, later that year. The report of that conference (McRoy and Helfferich 1977) makes interesting reading, looking back from the perspective of the 21st century. There is only one contribution from the southern hemisphere (Larkum 1977) with Australia referred to as a “little known region”. What we now know as the centre of seagrass biodiversity, Insular Southeast Asia and the broader Indo Pacific region, receives no mention at all. A significant and long-lasting outcome of the Leiden meeting was the birth of the journal “Aquatic Botany”.

The loss and degradation of the seagrass habitats: grounds for concern and guidelines for port development at Jervis Bay

Over the past 15 years, the potential loss of marine flora has become a matter for concern, both internationally and nationally, when port and associated developments are proposed. In an international context, the level of concern was illustrated by McRoy and others in 1973 and a call was made for greater research effort in the field of seagrass biology. More recently, these concerns have again been focused on by Weibe et al. (in press), when looking at the environmental effects of coal port development proposals by Pacific-rim nations. This raised awareness has occurred because of both the physical and the biological changes which have resulted from the loss degradation of seagrass meadows.

Announcement: "International Seagrass Biology Workshop (ISBW-7), Zanzibar, September 10-16, 2006"

Announcement: "International Seagrass Biology Workshop (ISBW-7), Zanzibar, September 10-16, 2006"

Dedicated Section: The Fifth International Seagrass Biology Workshop, 7-11 October 2002, Ensenada, Baja California, Mexico

Since 1996, seagrass experts have been meeting biennially to share knowledge of the biology of seagrasses and the animals associated with seagrass meadows. Previous workshops have taken place in Western Australia, Japan, the Philippines, and France. In 2002, the meeting was held in Mexico and four themes were chosen for the sessions: Ecophysiological Processes (Sven Beer, Chair), Plant-Animal Interactions (Kenneth L. HeckJR., Chair), Genetics and Reproductive Biology (Gabriele Procaccini and Michelle Wycott, Co-Chairs), and Changes in Seagrass Beds at the Local and Regional Scale (Fred T. Short, Chair). An additional session on Traditional Knowledge and Wisdom (Sandy Wyllie-Echeverria, Chair) provided an ethnobotanical perspective. Included here are abstracts accepted for the workshop, either as oral or poster presentations.

Marine Management: Marine Conservation

The research papers in this volume highlight some of the major issues in marine conservation and offer some exciting insights into future directions for research and management. It is particularly pleasing that the issue focuses on seagrasses, a component of marine biodiversity that is well recognized and with profound ecological significance, but has suffered widespread decline in its distribution over the past half century. The absence of any accurate inventory of seagrass resources makes it difficult to accurately assess the cumulative impact of human activity on them. However, the need to conserve seagrasses is well recognized and it is exciting to see the significant advances being made in bringing conservation biology techniques to seagrass research. The work of Waycott and Kenworthy (this issue) is clearly showing dramatic differences in the life-history strategies, genetic diversity and population structure of different seagrasses. It suggests that seagrasses are far from the homogenous organism that they seem to have been viewed as up until now. This also supports findings elsewhere which suggest that many of the classic paradigms regarding seagrass biology and ecology are based on inappropriate generalizations from a few species. For example, the work of Paling and others (in this issue) challenges the generally held view that we are unlikely to be able to transplant temperate species of seagrass back into disturbed areas.

Germination and seedling development of Halophila engelmannii aschers. (hydrocharitaceae) under axenic conditions

Seeds of Halophila engelmannii Aschers. stored in seawater in the dark after collection in Redfish Bay and Laguna Madre, TX, were germinated in the light under axenic conditions following ultrasonic and chemical (EtOH, NaOCl, HgCl 2) cleaning. After germination, axenic seedlings were transplanted individually into sterile media and their development compared with seedlings under non-axenic soil culture. Seedling development in a medium composed of 10% coconut milk, 1% charcoal and 1.5% agar in artificial seawater (ASP 2) approximated the rhizome production and stem and leaf pseudowhorl formation in non-axenic sediment cultures. After development under axenic conditions, rhizomal ramets with attached stems and leaf pseudowhorls were established in clonal, axenic cultures during a 6-month period following germination. The sustained culture of clones of H. engelmannii in an axenic system represents a long-sought goal for seagrass investigations and should promote efforts to understand the role of cation exchange in seagrass biology and the nature of chemical interactions with other organisms.

The condensed tannins (proanthocyanidins) in seagrasses

In a survey of 29 species in the 12 seagrass genera, those in the Potamogetonaceae that characteristically have tannin cells in the leaves (Posidonioideae: Posidonia; Cymodoceoideae: Halodule, Syringodium, Cymodocea, Thalassodendron, Amphibolis) contained compounds with the R f values and color reactions typical of condensed tannins. Species in the Potamogetonaceae that are not characterized by tannin cells in the leaves (Zosteroideae: Zostera, Phyllospadix, Heterozostera) contained compounds with the R f values associated with condensed tannins but without the typical staining reactions. Two of the three genera in the Hydrocharitaceae ( Enhalus, Thalassia) are characterized by tannin cells in the leaves and contain compounds with the R f values of condensed tannins but only some of the typical staining reactions. The third genus, Halophila, lacks tannin cells in the leaves and contains compounds with the R f values of condensed tannins without the typical staining reactions. The role of condensed tannins as feeding deterrents because of their protein-binding properties has been well established for many land plants, but their role in seagrass biology has not been assessed fully.

Seagrasses from the Philippines

Menez, Ernani G., Ronald C. Phillips, and Hilconida P. Calumpong. Seagrasses from the Philippines. Smithsonian Contributions to the Marine Sciences, number 21, 40 pages, 26 figures, 1983.—Seagrasses were collected from various islands in the Philippines during 1978-1982. A total of 12 species in seven genera are recorded. Generic and specific keys, based on vegetative characters, are provided for easier differentiation of the seagrasses. General discussions of seagrass biology, ecology, collection and preservation are presented. Local and world distribution of Philippine seagrasses are also included. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Seascape along the Atlantic coast of eastern North America. Library of Congress Cataloging in Publication Data Menez, Ernani G. Seagrasses from the Philippines. (Smithsonian contributions to the marine sciences ; no. 21) Bibliography: p. Supt. of Docs, no.: SI 1.41:21 1. Seagrasses—Philippines. I. Phillipps, Ronald C. II. Calumpong, Hilconida P. III. Title. IV. Series. QK495.A14M46 1983 584.73 83-600168

Transplantation of seagrasses, with special emphasis on eelgrass, Zostera marina L.

A background, listing the history of transplanting seagrasses is given. There is a need for seagrass field planting methods owing to the extremely high productivity of seagrasses and the perturbations they are subjected to. I have planted vegetative stocks and seeds of Zostera marina L. (eelgrass) across tidal zones, across latitudinal zones (from Alaska into Puget Sound), and into water deeper than indigenous growth. Data from these plantings indicate: (1) varietal distinctions based on leaf dimensions are invalid; (2) the possibility of local physiological race distinction in eelgrass; (3) the depth limit of eelgrass is due to a lack of suitable light deeper than a certain minimum depth; and (4) eelgrass seedlings require a higher light intensity than is present deeper than a certain minimum depth. Thus, transplanting experiments yield much more data concerning seagrass biology than just planting method information.