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Category: Marine Biodiversity

Seagrasses biomass-density relationship and ecological indicator

Seagrasses are marine flowering plant that comprises more than 60 different species. It grows by rhizome extension forming like grassland. Seagrasses also photosynthesize in submerged photic zone that mostly occur in shallow coastal water. In productive ecosystem seagrasses beds are diverse that can accommodate hundreds of associated species like fishes, macroalgae, mollusks and nematodes. However, biomass-density relationship becomes the center of research that describes the health of seagrass meadows.  Concurrently, biomass-density upper boundaries determined the maximum efficiency of space occupation. In which each distance reflects effective competence in packing biomass which proved as reliable ecological indicators.

 

Biomass-Density of Seagrasses

The researchers gathered 32 studies on 10 seagrasses species distributed worldwide reveals that seagrasses are limited by boundary line. Upon using the applied metric system on this particular research each stand of seagrass distance are perpendicular to the boundary.  However, seagrasses shows poor occupier of space compared to terrestrial plants and algae wherein less volume exploited per unit stand surface. Due to some reasons such as short shoot heights, wasted volume due to internodes length larger than shoot widths.

 

Seagrass comprises different species which shows diverse efficiency in space occupation. However, it occupies different bands of biomass-shoot density signifying conditional differentiation of co-occurring seagrass species. Furthermore, high shoot density dominates in favorable environments compare to harsh environment. As a result, this space occupation revealed as a good tool in understanding aspects of seagrasses ecology. Therefore, it serves as the basis to review fundamental aspects including clonal growth pattern, seasonality, competition and depth distribution.

 

Biomass-density of seagrass meadows is limited by interspecific boundary line making a maximum efficiency of space occupation. Though, species tends to differentiate the bands each scatter plot showing conditional differentiation. Moreover, during summer it shows the most favorable season and lower intertidal in correspond to depth. Therefore, the competence of space occupation requires biomass and shoots density of stands measured by vertical distance to the seagrasses.

 

Source: Prepared by Joan Tura from BMC Ecology

Volume 18: 24, October 19, 2018

Longest recorded trans-Pacific migration of a whale shark

Whale shark is a slow moving carpet shark and known as the largest extant fish species. It has a very huge mouth yet it feeds almost exclusively on plankton and small fishes. In marine biodiversity records whale shark showed the longest migratory path. Migratory behavior of marine species has been subject for research studies since it is important for optimizing growth and foraging opportunities. It also caters the breeding ground at discrete geographical locations and identification of different habitats across several jurisdictions. Also, it serves as the key for spatial planning and international policy management for ecosystem resources. Furthermore, gene flow, connectivity and population status are essentials for the marine conservation especially for migratory species.

 

Whale shark Migratory Route

On September 16, 2011 three female whale shark were tag using satellite transmitter model SPOT 253C. The tag specifies battery life wherein transmission occurs only when the animal is swimming near surface to maximize battery life. One female whale shark named Anne remained in Panamanian waters for 116 days then to eastern Pacific for 226 days. Then transmission began again at Hawaii after 235 days of silence then continued to Marshall Islands for about 268 days. But then transmission were interrupted again when the Anne reach the Mariana Trench.

 

So, the whale shark Anne travelled a long distance of 20,142 km approximately from Panama to Mariana Trench. Throughout this period Anne spent the entire time above thermocline with a temperature ranging from 15.1–35 °C. The route taken by Anne followed primarily westward North Equatorial Current similar to other whale that has been tracked previously. These results show that long periods without transmission do not necessarily entails tag shedding. Thus, this unusual long distance travelled of Anne and the intervals between detection offers evidence both tracking and genetic studies. It also suggests that whale shark is capable of long-distance travel.

 

Whale shark can migrate from Eastern Pacific to Western Indo-Pacific connecting two ocean basin using North Equatorial Current. It also imply that a potential passageway to reach Philippine Sea into South China Sea to get to Indian Ocean. Moreover, the results of this record are consistent to the genetic studies showing potential dispersal of whale shark. Overall, these two tracks showed by Anne expose the complexity of management of endangered species crossing multiple jurisdictions. Yet, the protection and conservation programs focused only at the local level rather than across Pacific.

 

Source: Prepared by Joan Tura from BMC Marine Biodiversity Records

Volume 11:8, April 19, 2018

Nutrients and bioactive potentials of green and red seaweeds

Seaweeds are macroscopic multicellular algae that have been used as food since ancient time. It was originated in Japan and then China particularly to the people who lived near the coastal areas. In addition to its nutritional value, seaweeds are rich source of structurally diverse bioactive compounds including polysaccharides, phlorotannins and pigments. Because of this, the demand  increases in the global trade wherein Korea is the major producers. In traditional Korean cuisines seaweeds used as soup, snack, pickle, vegetable and salad. Hence, this present research focuses on the edible green and red seaweeds found in Korea.

 

Green and Red Seaweeds Bioactive Compounds

Green seaweeds used to treat stomach disorders and hangovers because it contains 55% polysaccharides, 30% proteins, 13% ash and 1% lipids. It also have micro mineral such as calcium, manganese, iron, selenium, sodium, phosphate and potassium. Additionally, green seaweeds also used to treat wastewater and have significant medicinal value for rheumatism, high blood pressure and diabetes. In recent findings it has potentials bioactive properties to treat cancers and diabetes mellitus. Also it contains essentials oil to inhibit foodborne pathogens, anti-inflammatory, antioxidant and blood lipid reduction. Moreover, it has been used in traditional medicine for sunstroke, urinary diseases and hyperlipidemia. It is also useful to reduce eutrophication in mariculture waters that helps the survival rate productivity of shrimps and prawns.

 

Red seaweeds are the main source of hydrocolloids and contain vitamins A, B and C. It is also a rich source of carbohydrates particularly galactose and glucose. These red seaweeds are popularly known in agar production. And used as a raw material in bio-ethanol industry due to its high level of ethanol extraction efficiency. Likewise, both red and green seaweeds contain antioxidants properties due to its hydroxyl radical scavenging activity. That is responsible for neuro-protection against oxidative stress. In all, seaweeds have potential properties for anticancer, anti-diabetic, anti-obesity, anti-inflammatory, antimicrobial and anti-coagulant.

 

Therefore, seaweeds are vital source of food and medicine on different applications. The presences of secondary metabolites are potential to develop as functional materials due to its promising bioactive properties. Korea is one of the biggest consumers and producers wherein people mostly incorporate seaweeds on daily diets. This research suggests that increase consumption offers healthy benefits as well as utilization of seaweed materials as functional ingredients.

 

Source: Prepared by Joan Tura from  BMC Fisheries and Aquatic Sciences

Volume 21:19, 6 April 2018

 

First record: Common bottlenose dolphin in Canadian Pacific waters

Common bottlenose dolphins are the largest species of the beaked dolphins that inhabits in temperate and tropical oceans worldwide. These species are large that mostly found in groups and known to mixed with other species like whales and cetaceans. Common bottlenose dolphin diet mainly squid, eel, shrimp and wide variety of fishes by swallowing a whole than chewing it. Dolphins usually search prey using echolocation in a form of sonar. And uses sounds for communication like squeaks emitted from blowhole, whistles from nasal sacs and body language. The coastal of United States Pacific is known to have around 450 individuals while the offshore population about 3,495 individuals. In Canadian west coast no common bottlenose dolphin has been documented. However, on July 29, 2017 a sighting of this species mixed with cetaceans and killer whales has been observed.

 

Common bottlenose dolphins observed in Canadian waters

For the first time common bottlenose dolphins have been observed on July 29, 2017 in Canadian water. Each individual shows particular characteristics like short to moderate beak. A curved mouth line that dips downward resembling like a smile and tall falcate dorsal fin at the central back. Moreover, the body colors were usually light grey to black on the back and side while light to white color around the belly.

 

The sighting of the large group of common bottlenose dolphins is the first confirmed occurrence in Canadian Pacific waters. The location of sighting is approximately 1000 km northwest coast of America which signifies the first northernmost record of the species. About 200 dolphins were seen in the group in an unusual large aggregation. On the other hand it was also observed that this dolphins traveling closely with false killer whales, a typically offshore species.

 

The discovery of common bottlenose dolphins and false killer whales signifies the warming trends in North Pacific waters. Both of the species typically inhabit warm temperate waters in lower latitudes. But this sighting indicates that British Columbia, Canada oceanic conditions gives suitable habitat for them. It is also recorded that the show-up happened after a prolonged warming period.

 

Source: Prepared by Joan Tura from  Springer Nature BMC Marine Biodiversity

Vol. 11: 3, 20 April 2018