The invasive Caribbean Mytilopsis sallei (Bivalvia: Dreissenidae): A short review

The mussel-like bivalve species from the Caribbean, Mytilopsis sallei, is now well established in the vicinities of several ports in South and Southeast Asia. Although it may not be as notorious as its relative the zebra mussel Dreissena polymorpha, this brackish-water bivalve has the ability to colonise and displace native species in intertidal and subtidal habitats. It is also another testament to how well a tropical species can travel beyond its natural biogeographical boundaries. Here we briefly review its taxonomy, morphology, growth and reproduction, habitat and distribution, as well as its impact on natural habitats after invasion, based on published literature

Challenges in Managing Marine Bio-invasions via Shipping in Singapore

The economic, social and environmental impacts arising from the transfer and establishment of non indigenous marine species (NIMS) mediated through ship hull biofouling and ballast water discharges in the coastal marine environment require a regional approach to manage bio-invasions. As the coordinating body for maritime shipping affairs and protection of the marine environment, the International Maritime Organization (IMO) has been working with member states to adopt and ratify global conventions aimed at preventing invasive species transfer through shipping. As a major shipping hub and port-of-call in Southeast Asia, Singapore faces multiple challenges in managing marine bio-invasions including managing the transit of high risk vessels to environmentally sensitive areas beyond national borders. In this article, global frameworks for managing bio-invasions and its challenges for marine invasive pest management are discussed

Ultrastructure of pedal muscle as a function of temperature in nacellid limpets

Temperature and mitochondrial plasticity are well studied in fishes, but little is known about this relationship in invertebrates. The effects of habitat temperature on mitochondrial ultrastructure were examined in three con-familial limpets from the Antarctic (Nacella concinna), New Zealand (Cellana ornata), and Singapore (Cellana radiata). The effects of seasonal changes in temperature were also examined in winter and summer C. ornata. Stereological methods showed that limpet pedal myocytes were 1-2 orders of magnitude smaller in diameter (≈3.5μm) than in vertebrates, and that the diameter did not vary as a function of temperature. Mitochondrial volume density (Vv(mt,f)) was approximately 2-4 times higher in N. concinna (0.024) than in the other species (0.01 and 0.006), which were not significantly different from each other. Mitochondrial cristae surface density (Sv(im,mt)) was significantly lower in summer C. ornata (24.1±0.50μm2μm−3) than both winter C. ornata (32.3±0.95μm2μm−3) and N. concinna (34.3±4.43μm2μm−3). The surface area of mitochondrial cristae per unit fibre volume was significantly higher in N. concinna, due largely to the greater mitochondrial volume density. These results and previous studies indicate that mitochondrial proliferation in the cold is a common, but not universal response by different species from different thermal habitats. Seasonal temperature decreases on the other hand, leading preferentially to an increase in cristae surface density. Stereological measures also showed that energetic reserves, i.e. lipid droplets and glycogen in the pedal muscle changed greatly with season and species. This was most likely related to gametogenesis and spawnin

Thermal reaction norms and the scale of temperature variation: latitudinal vulnerability of intertidal Nacellid limpets to climate change

The thermal reaction norms of 4 closely related intertidal Nacellid limpets, Antarctic (Nacella concinna), New Zealand (Cellana ornata), Australia (C. tramoserica) and Singapore (C. radiata), were compared across environments with different temperature magnitude, variability and predictability, to test their relative vulnerability to different scales of climate warming. Lethal limits were measured alongside a newly developed metric of “duration tenacity”, which was tested at different temperatures to calculate the thermal reaction norm of limpet adductor muscle fatigue. Except in C. tramoserica which had a wide optimum range with two break points, duration tenacity did not follow a typical aerobic capacity curve but was best described by a single break point at an optimum temperature. Thermal reaction norms were shifted to warmer temperatures in warmer environments; the optimum temperature for tenacity (Topt) increased from 1.0°C (N. concinna) to 14.3°C (C. ornata) to 18.0°C (an average for the optimum range of C. tramoserica) to 27.6°C (C. radiata). The temperature limits for duration tenacity of the 4 species were most consistently correlated with both maximum sea surface temperature and summer maximum in situ habitat logger temperature. Tropical C. radiata, which lives in the least variable and most predictable environment, generally had the lowest warming tolerance and thermal safety margin (WT and TSM; respectively the thermal buffer of CTmax and Topt over habitat temperature). However, the two temperate species, C. ornata and C. tramoserica, which live in a variable and seasonally unpredictable microhabitat, had the lowest TSM relative to in situ logger temperature. N. concinna which lives in the most variable, but seasonally predictable microhabitat, generally had the highest TSMs. Intertidal animals live at the highly variable interface between terrestrial and marine biomes and even small changes in the magnitude and predictability of their environment could markedly influence their future distributions

Limpet feeding rate and the consistency of physiological response to temperature

Thermal reaction norms are fundamental relationships for geographic comparisons of organism response to temperature. They are shaped by an organism’s environmental history and provide insights into both the global patterns of thermal sensitivity and the physiological mechanisms underlying temperature response. In this study we conducted the first measure of the thermal reaction norm for feeding, comparing the radula rasping rate of two tropical and one polar limpet species. The consistency of thermal response was tested through comparisons with limpet duration tenacity. Feeding and duration tenacity of limpets are ecologically important muscular mechanisms that rely on very different aspects of muscle physiology, repeated concentric (shortening) and isometric (fixed length) contraction of muscles, respectively. In these limpets the thermal reaction norms of feeding limpets were best described by a single break point at a maximum temperature with linear declines at higher (Siphonaria atra) or lower temperatures (Nacella concinna and Cellana radiata) rather than a bell-shaped curve. The thermal reaction norms for duration tenacity were similar in the two tropical limpets. However, the rasping rate in Antarctic N. concinna increased linearly with temperature up to a maximum at 12.3 °C (maximal range 8.5–12.3 °C) when feeding stopped. In contrast, duration tenacity in N. concinna was maximal at 1.0 °C (−0.6 to 3.8 °C) and linearly decreased with increasing temperature. The thermal reaction norms of muscular activity were, therefore, inconsistent within and between species, indicating that different mechanisms likely underlie different aspects of species sensitivities to temperature

Upper Temperature Limits of Tropical Marine Ectotherms: Global Warming Implications

Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour−1, the upper lethal temperature range of intertidal ectotherms was 41–52°C, but this range was narrower and reduced to 37–41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2–3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming

A Pilot Study on Nurse-Led Rounds: Preliminary Data on Patient Contact Time

IMPORTANCE OF THE STUDY. Ward rounding has been a historical clinical method of inter-professional collaboration to support inpatient care through the sharing of mental models by exchanging information and discussing plans of care, treatment goals, and discharge plans for the patient. The extant literature reports that rounds are frequently led by doctors with infrequent nurse-physician collaboration and patients’ interactions with doctors during ward rounds tend to be brief. OBJECTIVE. To explore the effects of nurse-led morning ward rounds on patient contact time. DESIGN. An ethnographic prospective observational study comparing nurse-led and physician-led rounds. SETTING. A General Medicine ward at the National University Hospital in Singapore. INTERVENTION. A pilot intervention of nurse-led ward rounds for one week in June 2014. In the pilot intervention, nurses used the SPICES mnemonic to present their patients’ conditions to the clinical teams during morning rounds. MEASURES AND ANALYSES. Two observers shadowed the clinical teams for 57 patients. The amount of time that the clinical teams spent at the bedside of each patient was recorded. RESULTS. The results showed that the average time spent with patients at the bedside was significantly longer for nurse-led rounds compared to physician-led rounds. Also, the average time spent with patients at the bedside trended down toward the end of the 2-hour morning round time for resident-led ward rounds but it remained relatively consistent with an upward trend near the end of the 2-hour morning round for nurse-led rounds. CONCLUSION. The preliminary data suggests that quality time spent with patients at the bedside during morning rounds may be improved by nurse-led rounds

Metaphoric drawing narrative career counselling: Teaching work value and career identity statuses via experiential learning method

Metaphoric cards as a tool in counselling sessions are getting more scholarly attention in the fields of career counselling and education. In general, metaphoric cards consist of visual image that depicted daily life events and human expressions which are used as an alternative form of expression other than verbal communication. This paper aims to introduce metaphorical drawing as the experiential learning method in teaching narrative career counselling course. This is a qualitative study consists of metaphorical drawing and written reflection with six participants by using thematic analysis research method. The metaphorical drawing results revealed that, two new themes had been emerged in the exploration of work value and identity status. The results showed that some but not all participants benefited from the metaphorical drawing session to fully express their identity statuses. However, the combination of written reflection and verbal explanation of the metaphorical drawing did help the participants to convey their identity concern. In conclusion, metaphorical drawing session could be adopted in counsellor education to promote more understanding of narrative counselling technique and also in teaching work value and career identity status. For future research, it is important to look into how metaphorical technique can be introduced to school students in understanding their career choices

An inter-site study of biofouling recruitment on static immersion panels in major ports of South East Asia and India

Limited knowledge of native marine biodiversity hinders effective biodiversity management to safeguard South and Southeast Asia’s marine coastal environment against the threat of invasive species transfer through shipping. In particular, sessile marine biofouling organisms in South East Asian ports are poorly known. Through the support of the ASEAN-India Cooperation Project on the Extent of Transfer of Alien Invasive Organisms in South/South East Asia Region by Shipping, a coordinated effort to examine diversity of biofouling organisms in major port areas in Southeast Asia and India was made using polyvinylchloride (PVC) panels as recruitment surfaces in a static immersion study for a period of 12 months. Not surprisingly, the study revealed that fouling patterns differed between ports possibly as a result of dissimilar hydrographic conditions. However, there were also underlying similarities that reflected a regional uniformity in the composition of fouling communities. At the same time, the alien Caribbean bivalve Mytilopsis sallei was detected in Manila Bay (Philippines), Songkhla Port (Thailand) and Singapore. This is a first simultaneous biofouling survey involving scientists and government stakeholders from India and ASEAN nations of Brunei Darussalam, Indonesia, Lao PDR, Malaysia, Myanmar, Singapore, Thailand, Philippines and Vietnam