Ocean weather, biological rates, and unexplained global ecological patterns.

As on land, oceans exhibit high temporal and spatial temperature variation. This "ocean weather" contributes to the physiological and ecological processes that ultimately determine the patterns of species distribution and abundance, yet is often unrecognized, especially in tropical oceans. Here, we tested the paradigm of temperature stability in shallow waters (<12.5 m) across different zones of latitude. We collated hundreds of in situ, high temporal-frequency ocean temperature time series globally to produce an intuitive measure of temperature variability, ranging in scale from quarter-diurnal to annual time spans. To estimate organismal sensitivity of ectotherms (i.e. microbes, algae, and animals whose body temperatures depend upon ocean temperature), we computed the corresponding range of biological rates (such as metabolic rate or photosynthesis) for each time span, assuming an exponential relationship. We found that subtropical regions had the broadest temperature ranges at time spans equal to or shorter than a month, while temperate and tropical systems both exhibited narrow (i.e. stable) short-term temperature range estimates. However, temperature-dependent biological rates in tropical regions displayed greater ranges than in temperate systems. Hence, our results suggest that tropical ectotherms may be relatively more sensitive to short-term thermal variability. We also highlight previously unexplained macroecological patterns that may be underpinned by short-term temperature variability.

Complex parental effects impact variation in larval thermal tolerance in a vertically transmitting coral.

Coral populations must be able to adapt to changing environmental conditions for coral reefs to persist under climate change. The adaptive potential of these organisms is difficult to forecast due to complex interactions between the host animal, dinoflagellate symbionts and the environment. Here we created 26 larval families from six Montipora capitata colonies from a single reef, showing significant, heritable variation in thermal tolerance. Our results indicate that 9.1% of larvae are expected to exhibit four times the thermal tolerance of the general population. Differences in larval thermotolerance were driven mainly by maternal contributions, but we found no evidence that these effects were driven by symbiont identity despite vertical transmission from the dam. We also document no evidence of reproductive incompatibility attributable to symbiont identity. These data demonstrate significant genetic variation within this population which provides the raw material upon which natural selection can act.

Enhancing survivorship and growth of juvenile Montipora capitata using the Hawaiian collector urchin Tripneustes gratilla.

The biodiversity of coral reef habitats is rapidly declining due to the effects of anthropogenic climate change, prompting the use of active restoration as a mitigation strategy. Sexual propagation can maintain or enhance genetic diversity in restoration of these ecosystems, but these approaches suffer from a range of inefficiencies in rearing and husbandry. Algal overgrowth of juveniles is a major bottleneck in the production of sexually propagated corals that may be alleviated by co-culture with herbivores. We reared juvenile Montipora capitata alongside juvenile native Hawaiian collector urchins, Tripneustes gratilla, for 15 weeks and documented significant ecological benefits of co-culture. Urchin treatments significantly increased the survivorship of coral aggregates (14%) and individual settlers (24%). We also documented a significant increase in coral growth in the presence of urchins. These results demonstrate the utility of microherbivory in promoting coral growth and survivorship in ex situ conditions, providing valuable insight for restoration pipelines of native Hawaiian coral species.

Importance of depth and temperature variability as drivers of coral symbiont composition despite a mass bleaching event.

Coral reefs are iconic examples of climate change impacts because climate-induced heat stress causes the breakdown of the coral-algal symbiosis leading to a spectacular loss of color, termed 'coral bleaching'. To examine the fine-scale dynamics of this process, we re-sampled 600 individually marked Montipora capitata colonies from across Kane'ohe Bay, Hawai'i and compared the algal symbiont composition before and after the 2019 bleaching event. The relative proportion of the heat-tolerant symbiont Durusdinium in corals increased in most parts of the bay following the bleaching event. Despite this widespread increase in abundance of Durusdinium, the overall algal symbiont community composition was largely unchanged, and hydrodynamically defined regions of the bay retained their distinct pre-bleaching compositions. We explain ~ 21% of the total variation, of which depth and temperature variability were the most significant environmental drivers of Symbiodiniaceae community composition by site regardless of bleaching intensity or change in relative proportion of Durusdinium. We hypothesize that the plasticity of symbiont composition in corals may be constrained to adaptively match the long-term environmental conditions surrounding the holobiont, despite an individual coral's stress and bleaching response.

Community composition of coral-associated Symbiodiniaceae differs across fine-scale environmental gradients in Kane'ohe Bay.

The survival of most reef-building corals is dependent upon a symbiosis between the coral and the community of Symbiodiniaceae. Montipora capitata, one of the main reef-building coral species in Hawai'i, is known to host a diversity of symbionts, but it remains unclear how they change spatially and whether environmental factors drive those changes. Here, we surveyed the Symbiodiniaceae community in 600 M. capitata colonies from 30 sites across Kane'ohe Bay and tested for host specificity and environmental gradients driving spatial patterns of algal symbiont distribution. We found that the Symbiodiniaceae community differed markedly across sites, with M. capitata in the most open-ocean (northern) site hosting few or none of the genus Durusdinium, whereas individuals at other sites had a mix of Durusdinium and Cladocopium. Our study shows that the algal symbiont community composition responds to fine-scale differences in environmental gradients; depth and temperature variability were the most significant predictor of Symbiodiniaceae community, although environmental factors measured in the study explained only about 20% of observed variation. Identifying and mapping Symbiodiniaceae community distribution at multiple scales is an important step in advancing our understanding of algal symbiont diversity, distribution and evolution and the potential responses of corals to future environmental change.

Genetic patterns in Montipora capitata across an environmental mosaic in Kane'ohe Bay, O'ahu, Hawai'i.

Spatial genetic structure (SGS) is important to a population's ability to adapt to environmental change. For species that reproduce both sexually and asexually, the relative contribution of each reproductive mode has important ecological and evolutionary implications because asexual reproduction can have a strong effect on SGS. Reef-building corals reproduce sexually, but many species also propagate asexually under certain conditions. To understand SGS and the relative importance of reproductive mode across environmental gradients, we evaluated genetic relatedness in almost 600 colonies of Montipora capitata across 30 environmentally characterized sites in Kane'ohe Bay, O'ahu, Hawaii, using low-depth restriction digest-associated sequencing. Clonal colonies were relatively rare overall but influenced SGS. Clones were located significantly closer to one another spatially than average colonies and were more frequent on sites where wave energy was relatively high, suggesting a strong role of mechanical breakage in their formation. Excluding clones, we found no evidence of isolation by distance within sites or across the bay. Several environmental characteristics were significant predictors of the underlying genetic variation (including degree heating weeks, time spent above 30°C, depth, sedimentation rate and wave height); however, they only explained 5% of this genetic variation. Our results show that asexual fragmentation contributes to the ecology of branching corals at local scales and that genetic diversity is maintained despite strong environmental gradients in a highly impacted ecosystem, suggesting potential for broad adaptation or acclimatization in this population.

Expression plasticity regulates intraspecific variation in the acclimatization potential of a reef-building coral.

Phenotypic plasticity is an important ecological and evolutionary response for organisms experiencing environmental change, but the ubiquity of this capacity within coral species and across symbiont communities is unknown. We exposed ten genotypes of the reef-building coral Montipora capitata with divergent symbiont communities to four thermal pre-exposure profiles and quantified gene expression before stress testing 4 months later. Here we show two pre-exposure profiles significantly enhance thermal tolerance despite broadly different expression patterns and substantial variation in acclimatization potential based on coral genotype. There was no relationship between a genotype's basal thermal sensitivity and ability to acquire heat tolerance, including in corals harboring naturally tolerant symbionts, which illustrates the potential for additive improvements in coral response to climate change. These results represent durable improvements from short-term stress hardening of reef-building corals and substantial cryptic complexity in the capacity for plasticity.

A Field Primer for Monitoring Benthic Ecosystems using Structure-from-Motion Photogrammetry.

Structure-from-motion (SfM) photogrammetry is a technique used to generate three-dimensional (3D) reconstructions from a sequence of two-dimensional (2D) images. SfM methods are becoming increasingly popular as a noninvasive way to monitor many systems, including anthropogenic and natural landscapes, geologic structures, and both terrestrial and aquatic ecosystems. Here, a detailed protocol is provided for collecting SfM imagery to generate 3D models of benthic habitats. Additionally, the cost, time efficiency, and output quality of employing a Digital Single Lens Reflex (DSLR) camera versus a less expensive action camera have been compared. A tradeoff between computational time and resolution was observed, with the DSLR camera producing models with more than twice the resolution, but taking approximately 1.4-times longer to produce than the action camera. This primer aims to provide a thorough description of the steps necessary to collect SfM data in benthic habitats for those who are unfamiliar with the technique as well as for those already using similar methods.

Rapid, Precise, and Accurate Counts of Symbiodinium Cells Using the Guava Flow Cytometer, and a Comparison to Other Methods.

In studies of both the establishment and breakdown of cnidarian-dinoflagellate symbiosis, it is often necessary to determine the number of Symbiodinium cells relative to the quantity of host tissue. Ideally, the methods used should be rapid, precise, and accurate. In this study, we systematically evaluated methods for sample preparation and storage and the counting of algal cells using the hemocytometer, a custom image-analysis program for automated counting of the fluorescent algal cells, the Coulter Counter, or the Millipore Guava flow-cytometer. We found that although other methods may have value in particular applications, for most purposes, the Guava flow cytometer provided by far the best combination of precision, accuracy, and efficient use of investigator time (due to the instrument's automated sample handling), while also allowing counts of algal numbers over a wide range and in small volumes of tissue homogenate. We also found that either of two assays of total homogenate protein provided a precise and seemingly accurate basis for normalization of algal counts to the total amount of holobiont tissue.

The animal model in advanced laparoscopy resident training.

BACKGROUND AND AIM: Laparoscopic surgery is recognized as an established technique for several abdominal disorders. Aim of the present investigation was to assess the level of expertise of senior residents and to evaluate the role of the animal model on advanced laparoscopic training. METHODS: Overall, 60 residents underwent a training session on a porcine model under the guidance of experienced laparoscopic surgeons. Of these, 30 residents underwent a box-trainer preparation before starting the surgical procedure on the animal model, while a group of 20 repeated the course 3 months after the first session. Global Operative Assessment of Laparoscopic Skills (GOALS) was used to evaluate technical proficiency. RESULTS: Senior residents presented low mean scores for all the GOALS domains for both for the minor and major surgical procedure. The box-trainer led to an improvement in suturing skills (P<0.001). Comparison of the mean GOALS scores from the first to the second laparoscopic session demonstrated a significant improvement on the duration of the procedures (P<0.05), onset of major complications (P=0.01), need of the tutor (P=0.08), and confidence in treating intraoperative bleeding (P=0.01). CONCLUSIONS: National Resident Training Programs should take into consideration the present quality of training and attempt to develop alternative methods of training for laparoscopic surgery, such as, the animal model laboratory.

Resident training in laparoscopic colorectal surgery: role of the porcine model.

BACKGROUND: Laparoscopic colorectal surgery (LCRS) is an effective option for the treatment of various colorectal conditions. However, its implementation in surgical practice is still limited, and there are no clear guidelines for residency training requirements or evaluation of the level of expertise. The aim of this study was to assess the level of practical expertise of senior residents regarding LCRS in an animal porcine model. METHODS: At the Department of Biosciences of Rome, Tecnopolo of Castel Romano, 50 senior residents underwent training sessions on a porcine model under the direction of attending laparoscopic surgeons. A total of 20 residents underwent box trainer preparation before starting the surgical procedure on the animal model; and a group of 6 repeated the course 3 months after the first session. RESULTS: Overall, 90 % of the residents needed help during the surgical procedures, and only 9 residents (18 %) showed a high level of confidence when performing the surgery. Video-trainer preparation helped residents increase their laparoscopic ability (p = 0.04). Residents who attended two training courses showed significant improvement regarding the duration of the procedures, rate of complications, and the need of a tutor. CONCLUSIONS: The study demonstrated that the experience of senior surgical residents in regard to performing LCRS is less than ideal. A national training program should carefully consider the present quality of training in Italy and attempt to develop and integrate alternative methods for teaching laparoscopic surgery, perhaps by having an animal model laboratory.

Is laparoscopy safe and effective in nontraumatic acute abdomen?

BACKGROUND AND AIMS: Progress in laparoscopic experience has increased the number of laparoscopic procedures performed, even in emergency cases. Herewith, results in a prospective series of 300 patients laparoscopically treated for nontraumatic abdominal emergencies are presented with the intent to prove the safety and feasibility of laparoscopic approach in the treatment of acute abdomen. MATERIALS AND METHODS: From a prospective multicenter study performed between June 2008 and December 2009, the authors collected data on 300 patients with a provisional diagnosis of acute abdomen, laparoscopically treated or who underwent explorative laparoscopy. RESULTS: A correct diagnosis was made by means of laparoscopy in all 300 (100%) patients, and therapeutic laparoscopy was successfully performed in 270 (90%) patients. With laparoscopy, it was possible to modify the preoperative diagnosis and the treatment in 17 cases (5.6%). Upon statistical analysis, the conversion rate was correlated to the age of the patients (P<.0001) and to the operative time (P<.0001). The overall postoperative morbidity rate was 8%. Statistical analysis revealed that morbidity is correlated to the age of patients (P<.0001) and to the operative time (P<.0001). The mean hospital stay was 5.4 days. CONCLUSIONS: Laparoscopy has been shown to play a crucial role in the management of almost every abdominal emergency, offering, compared with the open approach, an initial diagnostic or explorative tool and a valid alternative in the treatment of the cause of acute abdomen with low morbidity and mortality rates.

Generation and analysis of transcriptomic resources for a model system on the rise: the sea anemone Aiptasia pallida and its dinoflagellate endosymbiont.

BACKGROUND: The most diverse marine ecosystems, coral reefs, depend upon a functional symbiosis between cnidarian hosts and unicellular dinoflagellate algae. The molecular mechanisms underlying the establishment, maintenance, and breakdown of the symbiotic partnership are, however, not well understood. Efforts to dissect these questions have been slow, as corals are notoriously difficult to work with. In order to expedite this field of research, we generated and analyzed a collection of expressed sequence tags (ESTs) from the sea anemone Aiptasia pallida and its dinoflagellate symbiont (Symbiodinium sp.), a system that is gaining popularity as a model to study cellular, molecular, and genomic questions related to cnidarian-dinoflagellate symbioses. RESULTS: A set of 4,925 unique sequences (UniSeqs) comprising 1,427 clusters of 2 or more ESTs (contigs) and 3,498 unclustered ESTs (singletons) was generated by analyzing 10,285 high-quality ESTs from a mixed host/symbiont cDNA library. Using a BLAST-based approach to predict which unique sequences derived from the host versus symbiont genomes, we found that the contribution of the symbiont genome to the transcriptome was surprisingly small (1.6-6.4%). This may reflect low levels of gene expression in the symbionts, low coverage of alveolate genes in the sequence databases, a small number of symbiont cells relative to the total cellular content of the anemones, or failure to adequately lyse symbiont cells. Furthermore, we were able to identify groups of genes that are known or likely to play a role in cnidarian-dinoflagellate symbioses, including oxidative stress pathways that emerged as a prominent biological feature of this transcriptome. All ESTs and UniSeqs along with annotation results and other tools have been made accessible through the implementation of a publicly accessible database named AiptasiaBase. CONCLUSION: We have established the first large-scale transcriptomic resource for Aiptasia pallida and its dinoflagellate symbiont. These data provide researchers with tools to study questions related to cnidarian-dinoflagellate symbioses on a molecular, cellular, and genomic level. This groundwork represents a crucial step towards the establishment of a tractable model system that can be utilized to better understand cnidarian-dinoflagellate symbioses. With the advent of next-generation sequencing methods, the transcriptomic inventory of A. pallida and its symbiont, and thus the extent of AiptasiaBase, should expand dramatically in the near future.

Role of a Cdc42p effector pathway in recruitment of the yeast septins to the presumptive bud site.

The septins are GTP-binding, filament-forming proteins that are involved in cytokinesis and other processes. In the yeast Saccharomyces cerevisiae, the septins are recruited to the presumptive bud site at the cell cortex, where they form a ring through which the bud emerges. We report here that in wild-type cells, the septins typically become detectable in the vicinity of the bud site several minutes before ring formation, but the ring itself is the first distinct structure that forms. Septin recruitment depends on activated Cdc42p but not on the normal pathway for bud-site selection. Recruitment occurs in the absence of F-actin, but ring formation is delayed. Mutant phenotypes and suppression data suggest that the Cdc42p effectors Gic1p and Gic2p, previously implicated in polarization of the actin cytoskeleton, also function in septin recruitment. Two-hybrid, in vitro protein binding, and coimmunoprecipitation data indicate that this role involves a direct interaction of the Gic proteins with the septin Cdc12p.

The role of cell cycle-regulated expression in the localization of spatial landmark proteins in yeast.

In Saccharomyces cerevisiae, Bud8p and Bud9p are homologous plasma membrane glycoproteins that appear to mark the distal and proximal cell poles, respectively, as potential sites for budding in the bipolar pattern. Here we provide evidence that Bud8p is delivered to the presumptive bud site (and thence to the distal pole of the bud) just before bud emergence, and that Bud9p is delivered to the bud side of the mother-bud neck (and thence to the proximal pole of the daughter cell) after activation of the mitotic exit network, just before cytokinesis. Like the delivery of Bud8p, that of Bud9p is actin dependent; unlike the delivery of Bud8p, that of Bud9p is also septin dependent. Interestingly, although the transcription of BUD8 and BUD9 appears to be cell cycle regulated, the abundance of BUD8 mRNA peaks in G2/M and that of BUD9 mRNA peaks in late G1, suggesting that the translation and/or delivery to the cell surface of each protein is delayed and presumably also cell cycle regulated. The importance of time of transcription in localization is supported by promoter-swap experiments: expression of Bud8p from the BUD9 promoter leads to its localization predominantly to the sites typical for Bud9p, and vice versa. Moreover, expression of Bud8p from the BUD9 promoter fails to rescue the budding-pattern defect of a bud8 mutant but fully rescues that of a bud9 mutant. However, although expression of Bud9p from the BUD8 promoter fails to rescue a bud9 mutant, it also rescues only partially the budding-pattern defect of a bud8 mutant, suggesting that some feature(s) of the Bud8p protein is also important for Bud8p function. Experiments with chimeric proteins suggest that the critical element(s) is somewhere in the extracytoplasmic domain of Bud8p.