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
Dolphins performing acrobatic tricks have, time and again, fascinated and mesmerized people. As early as 1860s, capturers took dolphins and other cetaceans (e.g. whales and porpoises) out of their aquatic habitats and held them in captivity in various parts of Europe and North America. At first, they kept them in a dolphinarium mainly as an amusement for a paying audience. Later on, they discovered that these aquatic marvels could be taught to perform tricks. Since then, people have gravitated to various dolphin shows as one of their “must-dos” off their bucket list.
Dolphins learning tricks
The tricks that dolphins can do seem limitless. Apart from their fantastic leaps and bounds, they can do complex tricks like tail-walking, playing ball, synchronized swimming, and rhythmic gymnastics. How do they learn these tricks? Trainers use positive reinforcement method to teach dolphins the jaw-dropping tricks. Accordingly, they reward them with food whenever they do a trick correctly. Watching them do these tricks, though, seems that they perform not only for the food reward but also for their own enjoyment based on their playful nature.
Wild dolphins’ ballistic jumps
Frequently, wild dolphins leap above the water surface. They do so by swimming fast near the surface, and then execute a ballistic jump. This behavior, called porpoising, seems a demonstration of their playful behavior. Nevertheless, another hypothetical reason surfaced. Accordingly, this porpoising behavior points to the benefit it furnishes. The friction up in the air is less; therefore, porpoising would help save dolphin energy.1
Seeing dolphins doing leaps and bounds in the wild is something that is truly remarkable yet not unusual. However, a pod of playful aquatic creatures in the wild were observed doing a trick rarely seen in the wild. Furthermore, the trick was something that they learned from a formerly captive dolphin.
Wild dolphins’ tail-walking trick
Recently, a study2 reported what they observed in wild dolphins. They saw a pod (particularly, a group consisting of nine dolphins) off the Australian coast that learned from a previously captive dolphin how to “walk” on water using their tail.
Tail walking is one of the fundamental tricks taught to captive dolphins. It involves rising vertically out of the water. Then, the dolphin moves forward or backward on top of the water. This skill is rarely seen in wild dolphins.2
Whale and Dolphin Conservation, together with the universities of St Andrews and Exeter, conducted a thirty-year study where they revealed that dolphins in the wild were able to learn a human-coached tail-walking trick from Billie. Billie is a rescued dolphin from a creek near Adelaide’s Patawalonga River in 1988. The dolphin was in captivity temporarily. During its captivity, it learned how to tail-walk. When it was released into the wild, it taught its companions by continuing to demonstrate the skill. Soon after, its peers copied it. In 2011, nine dolphins began tail walking. However, this spectacular display of “walking” by fins turned out to be just a fad. The number of wild dolphins that tail walk declined over time. As of 2014, only two of them remained to demonstrate the skill. 2
Dolphins, just as all the other living beings, deserve an inhabitable space in order to thrive and keep surviving. The ability of the dolphins to imitate skills could be used in spreading learnt behaviours that could be beneficial to their survival. The lengthy study that tracked the tail-walking behavior of Billie and the local dolphin community for years revealed an important insight. Accordingly, dolphins learning a behavior from each other can persist from one generation to the next. However, there is a tendency that certain learnt behaviors will fade, and, inopportunely, vanish through time.
— written by Maria Victoria Gonzaga
1 Weihs, D. (2002). “Dynamics of Dolphin Porpoising Revisited”. Integrative and Comparative Biology. 42 (5): 1071–1078. doi:10.1093/icb/42.5.1071
2 Whale and Dolphin Conservation. (2018 Aug. 29). WILD DOLPHINS LEARN FROM EACH OTHER TO ‘WALK ON WATER’…BUT IT’S JUST A FAD. Retrieved from https://uk.whales.org/news/2018/08/wild-dolphins-learn-from-each-other-to-walk-on-waterbut-its-just-fad
3 Whale and Dolphin Conservation (WDC). (2014 Nov. 5). Dolphins tailwalking – Port River, Adelaide | Whale and Dolphin Conservation. Retrieved from https://www.youtube.com/watch?v=6tn5TJfR3k4
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
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
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
Microplastics are less than 5mm diameter particles that came from different sources including cosmetics, clothing and industrial processes. This synthetic particle also originates from shipping spills, polystyrene beads and fishing gear. It is widely distributed in the environment particularly in aquatic and marine ecosystems. Microplastics classify in two, first it came from direct result of human material and product used. Second it derives from the breakdown of larger plastic debris. Because microplastics do not break down for many years, it is then ingested to aquatic and marine mammals in particular. Hence, the interest of this research study is to understand the impacts of this vast microplastic on marine ecosystem. As well as on the effects of organisms health that live on it.
Ingestion of Microplastics by large Mammals
The investigation of microplastics shows an empirical evidence of the trophic transfer from fish to marine top predator. There were 12 polymer types have been detected in fish and seals wherein ethylene propylene is the most common. And the polymer found in seals varies into almost ten types maybe because of the diversity of the marine environment. The study also indicates the variations of color and sizes of microplastics detected in fish and seals. Wherein blue, red and black colors are more prominent. As a result significant range of microplastics abundance, type, size, color and polymer types are not observed only among fishes. But within the marine environment in general wherein different kinds of species thrives in.
In addition detection of microplastics depends on the process of extraction as well as coloration. Since transparent particles are less obvious because of its translucent substrate. It also indicates that harbor seal contains more plastics in stomach suggesting that non-food items trap inside especially microplastics. Indeed, the research reveals strong correlation between polymer type in both fishes and seals. Thus, signifying that the microplastics found in seals is a consequence of ingestion rather than inhalation. Also it attributes the presence of microplastics particles in seals to the amount of trophic transfer from prey to marine top predator.
Therefore, the current study presents an empirical evidence of microplastics transfers across trophic levels from fish to top marine predator mammals. It is also found out that trophic transfer represents an indirect yet a major pathway of microplastics ingestion to any species. By which the feeding mechanism is through the consumption of the whole prey including humans.
Source: Prepared by Joan Tura from Environmental Pollution
22 February 2018
My work as a marine biologist has drawn me to the Coral Triangle, an area of our oceans consisting of the highest levels of marine biodiversity. You can imagine that the abundance of marine life led to a high reliance of local populations on seafood. It is a cruel irony that some of the methods used to harvest this seafood destroy the very foundations of seafood supply. So when I decided to hop on the Conservation bandwagon, the Coral Triangle was an obvious choice. (more…)
Welcome to guest blogger, marine biologist Sam Craven, from Mad As A Marine Biologist.
As a marine biologist and a diver I feel incredibly privileged to have seen many of the delightful examples of life that the most biodiverse ecosystem on our planet, the coral reefs, have to offer, but nothing has kept by attention and enthusiasm as much as the group of shell-less molluscs, the nudibranchs. (more…)