Investigation into Settlement Behaviour of Mussels and the Hydrology of a Selected Area with a View to Farming the Shellfish

<p>Physical observations in the Beatrix Basin, Marlborough Sounds, New Zealand, revealed four distinct regions: a partially exposed northern region with moderate water currents, low rainfall, small catchment area and scant freshwater inflow; a central highly exposed region with strong currents, moderate rainfall, no land catchment area and no direct freshwater inflow; an eastern region with a high degree of exposure and strong water movement, moderate rainfall, extensive catchment and seasonally high freshwater inflow; a southern sheltered region with sluggish water movement, comparatively high rainfall, extensive catchment and the highest rainfall in the study area. Differences between the four regions in monthly mean temperature and salinity were slight and there was an indication of more mixing in the central region than elsewhere. No thermocline was observed and surface water temperature demonstrated a diurnal rhythm in summer. Mean winter temperature fell to 10 degrees C and rose to 17 degrees C in summer. Mean salinity ranged from 32.8 degrees C in winter to 34.8 degrees C in summer and no halocline was present. Salinity fell occasionally after heavy rain, but tidal currents soon dissipated the freshwater except in the southern region where it persisted for a short time. The reproductive cycles of Perna canaliculus and Mytilus edulis aoteanus, the occurrence of their larvae in plankton samples, their season of settlement and peaks in settlement activity, were monitored. Physical environmental conditions preceeding or accompanying spatfall were recorded. A broad temporal relationship was found between spawning adult mussels, pelagic larvae, environmental conditions, and settlement of Perna canaliculus in Elie Bay. It appears that P. canaliculus spawned in early summer and in autumn when the water temperature was 18 plus-minus 0.5 degrees C. However, it was not possible to predict spatfall since the duration of the pelagic phase was not known and settlement is a function of larval survival and dispersal, as well as the presence of a suitable substrate. Accurate spatfall prediction is required to facilitate timed immersion of spat-collecting ropes while ensuring "seasoning" and avoiding fouling. As it was not possible to predict settlement by relating it to other biological or physical phenomena, this study sought an alternative spat-collecting material not so susceptible to fouling but still attractive to mussels. Carbon black fibrillated polypropylene film proved to be such an alternative. The determination of available food for mussels within the study area was attempted using particulate organic nitrogen as the indicator. The problems encountered are discussed. The concentration of particulate organic nitrogen was 11.78 microgram at N/litre. The larvae of Mytilus edulis aoteanus and Aulacomya maoriana were reared in the laboratory to the late veliger stage. The most likely causes of their failure to metamorphose were a too high larval density, an excess of food organisms and the lack of a suitable substrate for settlement. It was not possible to induce spawning of Perna canaliculus under controlled conditions.</p>

Investigation into Settlement Behaviour of Mussels and the Hydrology of a Selected Area with a View to Farming the Shellfish

<p>Physical observations in the Beatrix Basin, Marlborough Sounds, New Zealand, revealed four distinct regions: a partially exposed northern region with moderate water currents, low rainfall, small catchment area and scant freshwater inflow; a central highly exposed region with strong currents, moderate rainfall, no land catchment area and no direct freshwater inflow; an eastern region with a high degree of exposure and strong water movement, moderate rainfall, extensive catchment and seasonally high freshwater inflow; a southern sheltered region with sluggish water movement, comparatively high rainfall, extensive catchment and the highest rainfall in the study area. Differences between the four regions in monthly mean temperature and salinity were slight and there was an indication of more mixing in the central region than elsewhere. No thermocline was observed and surface water temperature demonstrated a diurnal rhythm in summer. Mean winter temperature fell to 10 degrees C and rose to 17 degrees C in summer. Mean salinity ranged from 32.8 degrees C in winter to 34.8 degrees C in summer and no halocline was present. Salinity fell occasionally after heavy rain, but tidal currents soon dissipated the freshwater except in the southern region where it persisted for a short time. The reproductive cycles of Perna canaliculus and Mytilus edulis aoteanus, the occurrence of their larvae in plankton samples, their season of settlement and peaks in settlement activity, were monitored. Physical environmental conditions preceeding or accompanying spatfall were recorded. A broad temporal relationship was found between spawning adult mussels, pelagic larvae, environmental conditions, and settlement of Perna canaliculus in Elie Bay. It appears that P. canaliculus spawned in early summer and in autumn when the water temperature was 18 plus-minus 0.5 degrees C. However, it was not possible to predict spatfall since the duration of the pelagic phase was not known and settlement is a function of larval survival and dispersal, as well as the presence of a suitable substrate. Accurate spatfall prediction is required to facilitate timed immersion of spat-collecting ropes while ensuring "seasoning" and avoiding fouling. As it was not possible to predict settlement by relating it to other biological or physical phenomena, this study sought an alternative spat-collecting material not so susceptible to fouling but still attractive to mussels. Carbon black fibrillated polypropylene film proved to be such an alternative. The determination of available food for mussels within the study area was attempted using particulate organic nitrogen as the indicator. The problems encountered are discussed. The concentration of particulate organic nitrogen was 11.78 microgram at N/litre. The larvae of Mytilus edulis aoteanus and Aulacomya maoriana were reared in the laboratory to the late veliger stage. The most likely causes of their failure to metamorphose were a too high larval density, an excess of food organisms and the lack of a suitable substrate for settlement. It was not possible to induce spawning of Perna canaliculus under controlled conditions.</p>

Effects of Nitrogen Supplementation With Wheat Straw on Productivity of Pleurotus Djamor (Rumph. Ex FR.) Boedijn

The present experiment was conducted in order to prepare a suitable substrate composition using wheat straw and also to ascertain the effect of various levels of nitrogen supplementation on the yield and biological efficiency of Pleurotus mushroom. The strain DMRP-205 of Pleurotus djamor was used in the study. Among different treatment combinations, maximum biological efficiency of 75.11% was recorded in T2 with 0.5% of urea supplementation. It was also observed that, though the higher nitrogen supplementation does not increase the yield proportionately, it has significant effect on the spawn run period, cropping duration and colour intensity of the basidiocarp. The study necessitates the nitrogen supplementation at optimum levels (0.5%) to realize the maximum yield in P. djamor cultivation. Bangladesh J. Bot. 50(2): 227-233, 2021 (June)

Microgreens: a newly merging product, aspects, prospectives, and disadvantages

In this article we demonstrate the connotation of microgreens, the newly merging product in the Russian market. Microgreens are normal plants planted in highly density on a substrate medium and harvested shortly after the first true leaves appear. Microgreens of many aromatic plants possess intensive flavour similar to its mature product. We also expound the aspects related to this product, including growth, harvesting time, Seeds utilization, light requirements, available suitable substrate, as well as the disadvantages related to its production. There is still a lot of controversy about the health benefits of consuming microgreens. Some researchers believe that there is currently not enough scientific evidence to support a higher nutrient level in microgreens than in mature plants. In this review, we discuss whether microgreening is a great addition to gardening or not. Still, other prospects for the future of this product indicates that the demand of the market for the microgreens will be strong especially with the wide spread of home-growing facilities like phytotrons and simple growing chambers.

Bryozoan diversity on a whale bone: an uncommon substrate from the continental shelf off NW Spain

Carcasses and bones of whales are interesting yet poorly understood habitats for invertebrates and microbial communities. Nevertheless, bryozoans have never before been reported in this particular habitat at the present day. Here, we present the first study on a bryozoan community colonizing a whale bone from the continental shelf off NW Spain at 128 m depth. Thirty-three species of bryozoans were identified, representing 50% of the known bryozoan diversity from this area and depth range. Despite this high biodiversity, no potential whale-fall specialists were detected: all the species are already known in the area, with several being more frequent in shallower or deeper waters. Our results support the hypothesis that the number of specialist taxa on whale-fall habitats decreases drastically on whale remains at depths of less than 260 m. These results also support the theory that whale-falls can serve as intermediate habitats where no other suitable substrate is present, facilitating habitat colonization.

Enhanced neurite outgrowth on electrically conductive carbon aerogel substrates in the presence of an external electric field

It has been established that aerogels are a suitable substrate for neuronal scaffold. In this study, the cell behavior of neuronal cells cultured on aerogels with an electrical stimulation is evaluated.

Substrates and organic sources in the production of seedlings of Physalis peruviana L.

The objective was to determine the effect of commercial substrates and organic sources on the production of cape gooseberry seedlings (Physalis peruviana L.). The design was completely randomized, in a 2×3 factorial scheme, with two commercial substrates for the production of seedlings (Carolina®, Bioplant®) and three organic sources (control, vermicompost enriched with yoorin thermophosphate and poultry manure). Adding poultry manure to commercial substrates causes negative effects on precocity and emergence. Carolina® is a suitable substrate to produce cape gooseberry seedlings without needing supplementation with organic sources. Bioplant® behaves more like an emergence conditioner, requiring supplementation with organic sources (preferably vermicompost). Seedlings suitable for transplanting are obtainable at 47 days after sowing.