Seagrass Research Articles

Applying Benthic Foraminiferal Assemblage to Evaluate the Coral Reef Condition in Dongsha Atoll lagoon.

Chienhsun Chen and Hui-Ling Lin (2017) Coral reefs in the South China Sea are threatened by environmental changes and anthropogenic disruptions. Foraminifera, a group of unicellular shelled protists, has been considered a reliable indicator of water quality and reef health. However, this indicator has not yet been used to study coral reefs in the South China Sea. In this study of foraminifera in the lagoon of Dongsha Atoll, both the assemblage diversity and the functional group composition were investigated. The FORAM index (FI), a numerical indicator based on functional group composition, was used to evaluate the condition of the coral reef of the Atoll lagoon. A typical assumption is that FI = 4 is the minimum index value corresponding to a suitable environment for the growth of calcifying organisms. Environments with FI values between 2 and 4 are unsuitable to marginal for recovery of coral communities after a mortality event. Data were recorded regarding a total of 287 foraminiferal species. Approximately 68% of the tests belonged to the porcelaneous taxa; the Quinqueloculina, Triloculina, and Pseudomassilina species were well represented. Hyaline foraminifera were less abundant than porcelaneous foraminifera; the agglutinated foraminifera were the least abundant. Multivariate analyses revealed four clustering groups. The functional groups were classified according to FI's definition; the heterotrophic group was the most abundant, accounting for 82% of foraminiferal abundance. The symbiont-bearing group was the second most abundant, with a relative abundance of 12%; and the stress-tolerant group was the least abundant. Two samples had FI values slightly higher than 4; Amphisorus and Calcarina were dominant, but the other symbiont-bearing foraminifera had lower values. These high FI values can be associated with seagrass meadows or relict shells in an altered environment. Eighty percent of the sediment samples had FI values lower than 4, indicating that most of the benthic habitats in the Dongsha lagoon are not suitable for coral growth and reef recovery. The present findings provide an alternative evaluation method based on foraminiferal assemblages for future studies on the environmental changes of coral reefs.

Macroalgae may mitigate ocean acidification effects on mussel calcification by increasing pH and its fluctuations

AbstractOcean acidification (OA) is generally assumed to negatively impact calcification rates of marine organisms. At a local scale however, biological activity of macrophytes may generate pH fluctuations with rates of change that are orders of magnitude larger than the long‐term trend predicted for the open ocean. These fluctuations may in turn impact benthic calcifiers in the vicinity. Combining laboratory, mesocosm and field studies, such interactions between OA, the brown alga Fucus vesiculosus, the sea grass Zostera marina and the blue mussel Mytilus edulis were investigated at spatial scales from decimetres to 100s of meters in the western Baltic. Macrophytes increased the overall mean pH of the habitat by up to 0.3 units relative to macrophyte‐free, but otherwise similar, habitats and imposed diurnal pH fluctuations with amplitudes ranging from 0.3 to more than 1 pH unit. These amplitudes and their impact on mussel calcification tended to increase with increasing macrophyte biomass to bulk water ratio. At the laboratory and mesocosm scales, biogenic pH fluctuations allowed mussels to maintain calcification even under acidified conditions by shifting most of their calcification activity into the daytime when biogenic fluctuations caused by macrophyte activity offered temporal refuge from OA stress. In natural habitats with a low biomass to water body ratio, the impact of biogenic pH fluctuations on mean calcification rates of M. edulis was less pronounced. Thus, in dense algae or seagrass habitats, macrophytes may mitigate OA impact on mussel calcification by raising mean pH and providing temporal refuge from acidification stress.

Density and size structure of the endangered fan mussel Pinna nobilis (Linnaeus 1758), in the shallow water zone of Maliakos Gulf, Greece

A total of 346 live animals of the endangered species fan mussel Pinna nobilis (Linnaeus 1758) were recorded in situ in the shallow water zone (<2m) within two sites of the marine protected area “Natura 2000” of Maliakos Gulf (Central Hellas). Our results showed that the recorded length (from 11.89 to 72.51 cm) of the fan mussels corresponds to ages that cover the majority of the species life time. Population densities were comparable to the higher values recorded previously in the Mediterranean Sea. The spatial distribution of species was clumped. Estimated total mortality was close to estimated natural mortality indicating that fishing activity does not significantly affect the population density and mortality of fan mussel in the study area. Population densities were related to sediment type, the buried length of animals was related to both sediment type and sea grass leaves size.

Efectos de la hiposalinidad en Thalassia testudinum (Hydrocharitaceae) del Parque Nacional Morrocoy, Venezuela

The year 1996 had a high pluviosity in Morrocoy National Park (western coastal zone, Venezuela) and low salinity in December 1996 affected the seagrass beds, dominated by Thalassia testudinum. Patches without T. testudinum were observed in localities of the park that used to have very dense populations of this plant. Sampling was done at Las Luisas to determine leaf productivity, turnover rate, short shoot density and relative biomass of plant sections, in order to compare with data obtained in September 1996, previous to the event. Green leaves, roots and rhizomes were the most affected parts. Mean green leaf biomass decreased in January and February 1997 to 5% of the plant's total biomass; mean root biomass decreased in March to 40% and mean rhizome biomass decreased in February to 30%. The density of the active short shoots decreased to a minimum in February, but in April it reached a value similar to that of September 1996. The density of the inactive short shoots decreased to a minimum in March, and they dissappeared in April, matching the increasing density of the active short shoots between these two months. In February 1997, 56% of the inactive short shoots showed evidence of leaf initiation. In January 1997 the leaf productivity and turnover rate values (2.72 it 0.35 g/m2/d and 2.15% leaf DW/d) were similar to the annual mean previously determined from Las Luisas (2.35 it 0.72 g/m2/d and 1.96% leaf DW/d). Nevertheless, the values of productivity and turnover rate detected at Las Luisas in April 1997 (4.88 it 2.14 g/m2/d and 4.66% leaf DW/d) were higher than those values previously reported for this location. In response to the mortality episode, the leaf productivity and turnover rate of T testudinum increased and the leaf initiation was activated in the inactive short shoots.

Shell Fouling and Behavior of the Caribbean Predatory GastropodCassis tuberosa

Abstract: The gastropod Cassis tuberosa (Linnaeus, 1758) usually lives in and on soft sediments and sea grass meadows. This carnivorous snail is primarily a semi-epifaunal and nocturnal hunter that, during daytime, rests burrowed in sediments. Around the Bahamian island of San Salvador, C. tuberosa has extended its behavior from nocturnal to metaturnal; feeding both night and day. This modification also involves further changes in behavior as an individual was observed resting epifaunally between rocks during the day even though this substrate was surrounded by soft bottoms. Epifaunal Cassis specimens are entirely encrusted primarily by coralline algae, but also by various green algae accompanied by vagile snails and crabs. The high degree of encrustation suggests that these snails do not remain burrowed for long periods of time. Cassis has thus extended its resting behavior from a semi-endofaunal to an epifaunal mode of life. The fouled shells also function as mobile benthic substrates for various organisms.

Towards a more sustainable waste management in Qatar: Retrofitting mindsets and changing behaviours

Historically, the peoples of Arabia have had a strong affinity with and respect for nature, recognising that their life depended on a mutually supportive relationship. The intertwined connections between people and nature included a reverence for camels that provide a dependable mode of transport across the harsh desert landscape; a deep affection for the majestic falcons that soared high above vast sand dunes in search of prey and a great pride in the saluki dog breed as a loyal and skilful hunting companion. Through the generations, nomadic and static tribes in the Gulf have learned to coexist with their hostile desert environment, following nature's path to water and fertile plains. And, while this bond endures, with the advent of oil wealth, which has brought with it unprecedented rates of development, it is a connection that at best is under strain and at worst on a catastrophic path as much desired rapid development brings with it demands on the environment and incursions into the landscape as never before: dredging, which destroys sea grass plains and their associated wildlife; agriculture, which requires ever more water, thereby depleting natural aquifers and necessitating higher levels of energy-consuming desalination and skyscraper cities, which demand increasing amounts of electricity for lighting, air-conditioning and residential comfort. Furthermore, an ever-growing mound of waste generated by a swelling population and increased consumerism do not seem favourable for the GCC region.What will it take to restore the human–environment balance? What needs to be retrofitted? Is it simply a matter of technical fixes, add-ons or replacements? Or is a more fundamental change needed? Do we need to retrofit mindsets, both individual and organisational, with a new set of overarching socially and environmentally driven principles that will allow Qatar to continue along its developmental path while enhancing its historical ties with the environment? In short, is it possible to design or retrofit our way towards a sustainable Qatar?It is argued in this paper that not only technological solutions and retrofits but also an associated change in mindsets and behaviours at all levels and in all communities will solve the waste management problems faced by Qatar. Drawing on examples from individual, organisational and community-driven initiatives in solid waste management in Qatar and a survey or attitudes towards waste, in this paper, we illustrate the complexity of the task ahead, the obstacles faced and the need for a “retrofit” of mindsets and behavioural change in order to achieve a transformation in solid waste management in Qatar.

Eukaryotic diversity in late Pleistocene marine sediments around a shallow methane hydrate deposit in the Japan Sea.

Marine sediments contain eukaryotic DNA deposited from overlying water columns. However, a large proportion of deposited eukaryotic DNA is aerobically biodegraded in shallow marine sediments. Cold seep sediments are often anaerobic near the sediment-water interface, so eukaryotic DNA in such sediments is expected to be preserved. We investigated deeply buried marine sediments in the Japan Sea, where a methane hydrate deposit is associated with cold seeps. Quantitative PCR analysis revealed the reproducible recovery of eukaryotic DNA in marine sediments at depths up to 31.0m in the vicinity of the methane hydrate deposit. In contrast, the reproducible recovery of eukaryotic DNA was limited to a shallow depth (8.3m) in marine sediments not adjacent to the methane hydrate deposit in the same area. Pyrosequencing of an 18S rRNA gene variable region generated 1,276-3,307 reads per sample, which was sufficient to cover the biodiversity based on rarefaction curves. Phylogenetic analysis revealed that most of the eukaryotic DNA originated from radiolarian genera of the class Chaunacanthida, which have SrSO4 skeletons, the sea grass genus Zostera, and the seaweed genus Sargassum. Eukaryotic DNA originating from other planktonic fauna and land plants was also detected. Diatom sequences closely related to Thalassiosira spp., indicative of cold climates, were obtained from sediments deposited during the last glacial period (MIS-2). Plant sequences of the genera Alnus, Micromonas, and Ulmus were found in sediments deposited during the warm interstadial period (MIS-3). These results suggest the long-term persistence of eukaryotic DNA from terrestrial and aquatic sources in marine sediments associated with cold seeps, and that the genetic information from eukaryotic DNA from deeply buried marine sediments associated with cold seeps can be used to reconstruct environments and ecosystems from the past.

SURVIVAL RATE AND GROWTH OF JUVENILE SANDFISH (Holothuria scabra) IN VARIOUS REARING CONDITIONS

Techniques for producing Holothuria scabra or sandfish sea cucumbers from aquaculture have been developed rapidly in the recent years to address the issues of decreasing sandfish population and increasing market demand. During the process of culturing H. scabra, the early stages of sandfish (i.e. larvae and juveniles) are the most critical of the development. Therefore, the Research and Development Division of the Marine Bio Industry – LIPI conducted a study to assess the growth performance of juvenile H. scabra ultured in four different rearing conditions: (i) indoor concrete tank, (ii) indoor fiberglass tank, (iii) outdoor concrete tank with 1 mm hapa mesh, and (iv) outdoor concrete tank with 3 mm hapa mesh. Each of the rearing condition was set with an initial juvenile density of 15 juveniles per tank with a mean initial weight of 14 g, and fed ad libitum with a mixed feed consisting of Enhalus acoroides sea grass, Pennisetum purpureum napier and cow manure. The experiments were conducted for 20 weeks between April 26 - September 23, 2013. After the experimental period, juveniles reared in the outdoor concrete tank with 1 mm mesh show the best performance with respect to their survival rate (48.89 ± 3.85 %),mean final weight (22.07 ± 1.01 g), final biomass (162.05 ± 18.17 g) and specific growth rate (0.15 ± 0.03% per day). Further studies that combine rearing conditions with different bottom substrates as well as investigating the effect of light are needed to optimize the production of H. scabra from aquaculture.

SURVIVAL RATE AND GROWTH OF JUVENILE SANDFISH (Holothuria scabra) IN VARIOUS REARING CONDITIONS

Techniques for producing Holothuria scabra or sandfish sea cucumbers from aquaculture have been developed rapidly in the recent years to address the issues of decreasing sandfish population and increasing market demand. During the process of culturing H. scabra, the early stages of sandfish (i.e. larvae and juveniles) are the most critical of the development. Therefore, the Research and Development Division of the Marine Bio Industry – LIPI conducted a study to assess the growth performance of juvenile H. scabra ultured in four different rearing conditions: (i) indoor concrete tank, (ii) indoor fiberglass tank, (iii) outdoor concrete tank with 1 mm hapa mesh, and (iv) outdoor concrete tank with 3 mm hapa mesh. Each of the rearing condition was set with an initial juvenile density of 15 juveniles per tank with a mean initial weight of 14 g, and fed ad libitum with a mixed feed consisting of Enhalus acoroides sea grass, Pennisetum purpureum napier and cow manure. The experiments were conducted for 20 weeks between April 26 - September 23, 2013. After the experimental period, juveniles reared in the outdoor concrete tank with 1 mm mesh show the best performance with respect to their survival rate (48.89 ± 3.85 %),mean final weight (22.07 ± 1.01 g), final biomass (162.05 ± 18.17 g) and specific growth rate (0.15 ± 0.03% per day). Further studies that combine rearing conditions with different bottom substrates as well as investigating the effect of light are needed to optimize the production of H. scabra from aquaculture.

Interspecific differences in habitat selection of syngnathids in the Ria Formosa lagoon, Portugal

Interspecific patterns of local population abundances and differences in habitat preference of two seagrass resident pipefish species of the genus Syngnathus were investigated in a semi-protected lagoon system in Southern Portugal. The results of the combination of field surveys across different seagrass meadows and laboratory habitat choice experiments between May and September 2014 demonstrate that the pipefish population structure in a single-species meadow composed of Zostera noltei differed significantly from the ones in a single-species meadow of Cymodocea nodosa and a mixed meadow of both seagrasses. In addition, the two most abundant pipefish species, Syngnathus typhle and Syngnathus abaster, showed interspecific and intersexual differences in habitat selection both on a macro- and a microhabitat scale in laboratory experiments. The study suggests that in addition to the investigated structural characteristics of sea grasses (i.e. shoot length and density), other factors such as flow velocity may influence habitat selection of syngnathids.

Analisis Kadar Unsur Nitrogen (N) Dan Posforus (P) Dalam Lamun (Enhalus acoroides) Di Wilayah Perairan Pesisir Kabonga Besar Kecamatan Banawa Kabupaten Donggala

The caring of community and local government toward sustainability of seagrass ecosystem has not built properly as well as toward the ecosystem of coral reef and mangrove, as a result, this plant needs attention for its sustainability. One of sea grass’s species which is avalaible abundantly in Banawa district Donggala regency, is enhalus acoroides type. This research aims to know the level of nitrogen dan phosphorus in enhalus acoroides which grow in the bay of Kabonga besar, Banawa district Donggala regency. Determination of nitrogen level used kjeldhal method which consisted of destruction, destilation, titration and phosphorus used wet ash method which continued to use the UV-Vis spectrometry. The result showed that the level of nitrogen in sea grass (enhalus acoroides) type was 1.89 in percentage and phosphorus was 0.413 in percentage.

Range extension of a vulnerable Sea horse Hippocampus fuscus (Actinopterygii: Syngnathidae) on the north-eastern Bay of Bengal coast

The study describes the range extension of the sea horse Hippocampus fuscus from the south to north east coastal waters of the India, Bay of Bengal. After 99 years since initial discovery, the Hippocampus fuscus was reported within the southern sector of the Chilika Lake. The extension range may be due to the East India Coastal Current of the Bay of Bengal and the predominance of extensive sea grass meadows within the southern sector of Lake.

Coastal Restoration Based on Institutional Approach: A case study in the city of Probolinggo, East Java Province, Indonesia

The coastal area in Indonesia is currently experiencing a very heavy pressure, whether caused by human activities, or caused by natural processes. Damage to coastal ecosystems like mangroves, coral reefs, sea grass beds, estuaries and the region has reached at an alarming rate. It is estimated that more than 41 percent of the coastal area in Indonesia is experiencing environmental degradation. This leads to the coastal region can no longer support the region's ecological system. Associated with more severe coastal damage, it is necessary efforts to save the coast through the people residing in coastal areas as a subject of coastal development. In this regard, more comprehensive studies are needed to determine the institutional aspects as an effective solution for dealing with coastal restoration.The aim of this research is to handle of coastal environmental damage by coastal restoration based on institutional aspect, and to formulate institutional models in accordance with local wisdom. Therefore, it is needed a statistical approach with assumption that there is relationship between restoration of mangrove with institutional aspect. Partial Least Square (PLS) is used to examine such relationship. To analyse priority of institutional strategy, it is used SWOT analysis.The result of this research is that to overcome the damage of mangroves, it is necessary to formulate activities synergy among local government, private and local people. Therefore, Co-management approach is needed to strengthen mangrove Community Working Group. (CWS).

Influence of feeding Murciano-Granadina Goats with Posidonia oceanica Banquettes on the Resulting Milk and Cheese

The inclusion in the diet of biological products of a biodegradable nature is a highly valued strategy with many advantages. Posidonia oceanica is a seagrass species which may be used as a substitute for straw. In this study, one group of goats (control) was fed a normal diet that contained straw, while the straw in the diet of the other group was replaced by P. oceanica. No significant differences were found between the control and experimental group regarding the main physicochemical and sensorial parameters of the resulting milk and cheese; although the cheese from the group fed P. oceanica was firmer and chewier. When the milk-clotting time was determined under different assay conditions, the origin of the milk was found to have a significant effect, the milk from animals fed with algae showing greater technological suitability. In conclusion, P. oceanica can be used as a straw substitute, promoting a sustainable livestock system and contributing to the maintenance of meadows.

Probing Coastal Eco-Tourism in Pasir Putih Beach, Indonesia

Indonesia’s tourism-ministry is targeting 20 million foreign tourists’ visiting Indonesia in 2019. Moreover, traveling to the natural-coastal eco-tourism becomes a tourist’s trend and their priority’s decision on considering their leisure time’s plan. “Pasir Putih” beach is one of the natural beach-tourism, have been attractive natural-scenic in Lampung. The existing performance indicated that the destination is quite ordinary. Therefore, the visitation of tourist to Lampung increased averagely up to 30% annually. While, recently there has been some environmental quality problem such as a damage to coral reefs and sea grass beds around the destination. This lowers the quality to the environment in the future that will impact the quantities, and the visit of tourists. It is extremely clear visible in the results of gap analysis tourism performance bunch, who demonstrate the need for effort to control the utilization of the beach environment and implement programs for the coast protection of coastal areas for improving and maintaining its quality, which is very important, because such activity can provide economic contribution to the community and local government. Moreover, on the supply sides, travel agent collaborates with travel agency get to reduce the negative impact of coastal-tourism activity by conserving various coral reefs, sea grass. This effort would occur by developing local-community empowerment on conserving both sides of coastal-destination that becomes the favorites scenic for them on developing natural coastal tourism along the coastline.

Type and Concentration of Sea Grass and Effect on Nutrition Content of Sago Cookies

Type and Concentration of Sea Grass and Effect on Nutrition Content of Sago Cookies

The utilization of Depth Invariant Index and Principle Component Analysis for mapping seagrass ecosystem of Kotok Island and Karang Bongkok, Indonesia

Seagrass perform a variety of functions within ecosystems, and have both economic and ecological values, therefore it has to be kept sustainable. One of the stages to preserve seagrass ecosystems is monitoring by utilizing thespatial data accurately. The purpose of the study was to assess and compare the accuracy of DII and PCA transformationsfor mapping of seagrass ecosystems. Fieldstudy was carried out in Karang Bongkok and Kotok Island waters, in Agustus 2014 and in March 2015. A WorldView-2 image acquisition date of 5 October 2013 was used in the study. The transformations for image processing data were Depth Invariant Index (DII) and Principle Component Analysis (PCA) using Support Vector Machine (SVM) classification. The result shows that benthic habitat mapping of Karang Bongkok using DII and PCA transformations were 72%and 81% overall’s accuracy respectively, whereas of Kotok Island were 83% and 84% overall’s accuracy respectively. There were seven benthic habitat types found in karang Bongkok waters and in Kotok Island namely seagrass, sand, rubble, coral, logoon, sand mix seagrass, and sand mix rubble. PCA transformation was effectively to improve mapping accuracy of sea grass mapping in Kotok Island and Karang Bongkok.

三陸沿岸域におけるアマモ場の東日本大震災前後の変化

三陸沿岸域におけるアマモ場の東日本大震災前後の変化

Diet of the Volcano Keyhole LimpetFissurella volcano(Gastropoda: Fissurellidae) in Subtropical Rocky Reefs of the Baja California Peninsula

Diet of the volcano keyhole limpet Fissurella volcano was determined from stomach contents of 56 specimens collected from two rocky reefs along the west coast of the Baja California Peninsula of Mexico in July and November 2006 and March 2007. We identified 40 taxa, including 27 diatoms, one cyanoprokaryota, eight macroalgae (mainly red algae), one sea grass, and three protozoans. Food items 20% in relative frequency were diatoms, cyanoprokaryota, and Pyropia sp. Among the diatoms, 10 species represent 80% of relative frequency ( Grammatophora marina, Cocconeis speciosa, Navicula longa, Amphora sp., Cocconeis dirupta, Tabularia investiens, Cocconeis plancentula, Cocconeis distans, Tabularia fasciculata , and Cocconeis notata ). These findings suggest that Fissurella volcano is a herbivore with preference for diatoms, periphyton, and foliose and filamentous red seaweeds.

Predatory behavior of the paguroid Dardanus venosus (H. Milne-Edwards, 1848) (Anomura: Diogenidae) on the snail Aurantilaria aurantiaca (Lamarck, 1816) (Gastropoda: Fasciolariidae)

Abstract Paguroids are usually detritivorous organisms and the occurrence of predation on mollusks is very unusual. This contribution reports the occurrence of a predatory behavior of the paguroid Dardanus venosus (H. Milne Edwards, 1848) on the snail Aurantilaria aurantiaca (Lamarck, 1816). Single specimen of paguroid was found attacking the snail in a sea grass meadow dominated by Halodule wrightii Ascherson on the coast of Ceara, northeastern Brazil. The paguroid and gastropod specimens were brought to the laboratory and placed in an aquarium and the behavior was recorded by photos. Paguroid behavior was characterized by sequencial movements of chelipeds in the attack to the snail when the snail was hold by paguroid ambulatory legs. External lip of shell aperture, operculum and foot of the gastropod were severely damaged.