Self-powered wireless sensing platform for monitoring marine life based on harvesting hydrokinetic energy of water currents

This work presents fully underwater triboelectric nanogenerators (UTENGs) to harvest hydrokinetic energy of water currents towards self-powered marine life sensors and IoT applications.

Meltdown

Climate change is happening all around us, and one of the telltale signs is melting glaciers. We hear about it almost daily, pieces of ice the size of continents breaking off of Antarctica or the polar arctic ice breaking up and disappearing more and more quickly opening up navigational routes once unavailable due to thick winter ice cover. Will melting ice and glaciers so far away change our lives? Meltdown takes us deep into the cryosphere, the Earth’s frozen environment and picks apart why glacier melt caused by climate change will alter (and already is altering) the way we live around the world. From rising seas that will destroy property and flood millions of acres of coastal lands, displacing hundreds of millions of people, to rising global temperatures due to reflectivity changes of the Earth because of decreased white glacier surface area, to colossal water supply changes from glacier runoff reduction, to deadly glacier tsunamis caused by the structural weakening of ice on high mountaintops that will take out entire communities living in glacier runoff basins, to escaping methane gas from thawing frozen permafrost grounds, and changing ocean temperatures that affect jet streams and ocean water currents around the planet, glacier melt is altering our global ecosystems in ways that will drastically change our everyday lives. Meltdown takes us into the little-known periglacial environment, a world of invisible subterranean glaciers in our coldest mountain ranges that will survive the initial impacts of climate change but that are also ultimately at risk due to a warming climate. By examining the dynamics of melting glaciers, Meltdown helps us grasp the impacts of a massive geological era shift occurring right before our eyes.

A brainstem integrator for self-localization and positional homeostasis

To accurately track self-location, animals need to integrate their movements through space. In amniotes, representations of self-location have been found in regions such as the hippocampus. It is unknown whether more ancient brain regions contain such representations and by which pathways they may drive locomotion. Fish displaced by water currents must prevent uncontrolled drift to potentially dangerous areas. We found that larval zebrafish track such movements and can later swim back to their earlier location. Whole-brain functional imaging revealed the circuit enabling this process of positional homeostasis. Position-encoding brainstem neurons integrate optic flow, then bias future swimming to correct for past displacements by modulating inferior olive and cerebellar activity. Manipulation of position-encoding or olivary neurons abolished positional homeostasis or evoked behavior as if animals had experienced positional shifts. These results reveal a multiregional hindbrain circuit in vertebrates for optic flow integration, memory of self-location, and its neural pathway to behavior.

Ontogenetic niche specialisation of the spider crab Libinia ferreirae associated with the medusa Lychnorhiza lucerna

Symbiotic relationships in marine environments are not fixed and can change throughout the animal’s life. This study investigated the ontogeny of symbiosis of the spider crab Libinia ferreirae with the host medusa Lychnorhiza lucerna. We described the type of relationship, the temporal correlation among species and food habits. More than 50% of the sampled crabs were symbionts, most in early life stages. The highest number of crabs found in a single medusa was 11. Symbiosis was observed throughout most of the year but was more evident in warm periods. The crab has many benefits in this relationship with a medusa. One is the use of food resources captured by the medusa, primarily copepods. Since the crab steals the medusa's food, it is a kleptoparasitic relationship. There is a niche partition between symbiont and the free-living crabs as they occupy different habitats and use nonoverlapping food resources. Previous research reported that symbiosis first developed during the crab’s last larval phase (megalopa) when crab and medusa are in the same habitat. Observation of the crab's behaviour shows that symbiosis occurs when the crab can grab to the medusa when the host touches the sea bottom. The crab also took advantage of water currents, releasing itself from the substrate and then drifting towards the medusa. The symbiotic relationship that crabs have with the medusa provides then with a nursery, food resources, shelter, dispersion, and decreased competition with free-living adult crabs, all essential for the crab's survival.

Performance Of Nile Tilapia Oreochromisniloticus (L) In Cages of Varied Stocking Densities

Cage culture is a new venture in Tanzania, and the knowledge of stocking density in cages is still needed. Growth performance of Nile tilapia, Oreochromis niloticus (L) stocked in cages of varied stocking densities and their impacts on waters were evaluated for 212 days in Shirati Bay of Lake Victoria. We started with fingerlings of 18.0±2.1 g, 19.9±14.7 g, and 18.5 ± 8.0 g mean weights. They were raised in cages at stocking densities of 70 (Treatment I), 100 (Treatment II), and 130 fish/ m3 (Treatment III) each in triplicates. We recorded monthly fish weights and lengths, total nitrogen, total phosphorus, ammonia, and micro-benthos. Parameter such as dissolved oxygen, pH, temperature, and transparency were all monitored weekly. The final average fish weights were 374.1±59.8g in treatment I, (194.8 ± 63.7g) in II, and (273.2±20.6g) in III. Percentage fish survival was the highest in treatment I (76.7%), followed by II (65.4%) and III (54.3%). Specific growth rate, production and yield was the highest in treatment I, and significantly different from treatments II and III (p <0.05). This indicates that Nile tilapia flourished well in the lowest stocking density. Water quality parameters were within the range of fish culture throughout the study and observation of water depth, distance from the shoreline, and the prevailing water currents showed lack of adverse environmental effect caused by fish cage culturing

Utilization of Tithonia diversifolia as Ruminant Feed

<p>Forage is an important component in raising ruminants. Limited land specifically for forage cultivation is a big challenge in providing forage. <em>Tithonia diversifolia</em> is a promising species used as feed for ruminants because it is easy to grow in various places without being cultivated, such as on roadsides or as fences. This paper aims to give information about <em>Tithonia diversifolia</em> and its cultivation, production, nutritional value and its utilization as forage for ruminant. This plant can be propagated vegetatively and generatively. The spread of seeds can be carried by vectors such as humans, livestock, water currents and wind. <em>T. diversifolia</em> plants have several advantages: fast growing, high production, high crude protein content, resistance to high cutting frequencies and tolerance to acidic soils. Apart from these advantages, this plant also has some weaknesses because it contains several secondary compounds which may affect rumen fermentation. This weakness can be overcome by addition of feed aditive, charcoal or by processing it into silage. <em>T. diversifolia</em> has been used as feed for small and large ruminants either as single or mixed feed with concentrates and other forages with relatively high digestibility. The dry matter consumption of <em>T. diversifolia</em> reaches nearly 600 g/h/d when given as single feed to goats. However, recommended feeding level is 30% of total ration. </p>

Five hundred million years to mobility: directed locomotion and its ecological function in a turtle barnacle

Movement is a fundamental characteristic of life, yet some invertebrate taxa, such as barnacles, permanently affix to a substratum as adults. Adult barnacles became ‘sessile’ over 500 Ma; however, we confirm that the epizoic sea turtle barnacle, Chelonibia testudinaria , has evolved the capacity for self-directed locomotion as adults. We also assess how these movements are affected by water currents and the distance between conspecifics. Finally, we microscopically examine the barnacle cement. Chelonibia testudinaria moved distances up to 78.6 mm yr −1 on loggerhead and green sea turtle hosts. Movements on live hosts and on acrylic panels occasionally involved abrupt course alterations of up to 90°. Our findings showed that barnacles tended to move directly against water flow and independent of nearby conspecifics. This suggests that these movements are not passively driven by external forces and instead are behaviourally directed. In addition, it indicates that these movements function primarily to facilitate feeding, not reproduction. While the mechanism enabling movement remained elusive, we observed that trails of cement bore signs of multi-layered, episodic secretion. We speculate that proximal causes of movement involve one or a combination of rapid shell growth, cement secretion coordinated with basal membrane lifting, and directed contraction of basal perimeter muscles.

Contamination of Heavy Metals (Pb and Cu) at Tin Sea Mining Field and Its Impact to Marine Tourism and Fisheries

The dynamics of heavy metals (Pb and Cu) distribution near sea mining locations can show a negative impact on fisheries resource management. The study was conducted at the coastal area of Tanah Merah Beach, Central Bangka Regency, the geographical location at 02o12'50 "S and 106o13'00" E. This study aims to determine the extent of heavy metals (Pb and Cu) distribution adjacent sea mining field and its impact on marine tourism and fisheries. Purposive sampling method was used to identify the sampling locations from 13 closest locations to the farthest from marine mining sources. The result show that the closest and farthest Pb and Cu values from the tin mining activities were 0.16 mg.L-1; 0.03 mg.L-1 and 0.02 mg.L-1; <0.003 mg.L-1. The Hydro-oceanographic conditions from the highest to the lowest water currents of 0.03 m.s-1 - 0.001 m.s-1. This research represented the east monsoon, which showed that the heavy metal distributions dynamics are not too distance-reaching due to weak water currents, so that the dilution and sedimentation rate is slow. It is stated that the waters are polluted where the highest contamination value is indicated by the location closest to the source of marine mining and further weakened at the location farthest from the source of pollutants. Environmental impact from that activity has significantly threatened marine tourism and fishery activities by reducing economic benefits that given from marine and coastal environmental. Urgently, it is necessary to regulate like zoning tin mining activities and sites for the sustainable common purposes and prevent conflicts.