South Bay Research Articles

A new model-based coastal retention index (CORE) identifies bays as hotspots of retention, biological production and cumulative anthropogenic pressures

Retention is a key driver of biological productivity near the coast since increased concentrations of planktonic particles in retention hotspots boost local primary production, availability of particulate food and larval recruitment. Known retention sites, such as bays, are also places where anthropogenic pressures accumulate in the form of pollution, harmful algal blooms, fisheries, aquaculture and port developments. In the face of these growing hazards, South African bays were recently declared ‘threatened’ priority sites for enhanced conservation and marine spatial planning (MSP). Multidisciplinary studies that spatially relate human impacts to physical features (such as retention patterns) and ecological processes (such as primary production) are valuable in this context. This study made use of a high resolution CROCO (Coastal and Regional Ocean Community Model) model along with the Parcels particle-tracking tool to develop a spatio-temporal coastal retention index (CORE) for the South African coastal ocean. To explore links between retention, biological productivity and anthropogenic impacts, a monthly time series of CORE (2001–2012) was evaluated in relation to satellite-derived coastal chlorophyll-a (Chl-a) and an index of cumulative human pressure. CORE showed variable temporal relationships with Chl-a among different subregions, however, when integrated over time, their spatial trends and peaks commonly aligned. This was most obvious on the south coast, where retention, Chl-a and human pressures peaked in the majority of bays that characterise this region. In the case of St Helena Bay on the west coast, CORE failed to represent a prominent retentive feature associated with upwelling, due to rapid alongshore advection of particles outside the 25-km retention radius of CORE. Despite this limitation, CORE provided profound insight into the variability of the coastal circulation around South Africa and its coupling with other socio-ecological variables. By contributing a novel data layer for MSP, CORE assists the integrated coastal management of bay ecosystems that face the hazards of multiple destructive uses.

Mapping the habitats of a complex circalittoral rocky shelf in the Cantabrian Sea (south Bay of Biscay)

This work focuses on the study of habitats and communities of a high structural complexity area at different levels and scales. This gives us a better understanding of an area from an ecological point of view and at the same time provides us with tools that will facilitate management measures. It was developed in a complex circalittoral rocky platform of the central Cantabrian Sea (Bay of Biscay). The sampling was carried out using a towed photogrammetric vehicle and a rock dredge, which was used for the identification of the species. The first level of the study was the abiotic characterization of the area and the analysis of the communities. These analysis were developed using the unsupervised k-means classification method. For abiotic characterization we used the variables directly associated with the composition and morphology of the ground, such as backscatter, BPI (Bathymetric Position Index), roughness and slope. Depth was also included to discriminate between the circalittoral and bathyal zones. We obtained 5 different classes, which we related to the ground types observed by photogrammetry. In the analysis of the communities, the cluster was based on the sampling units extracted from the images (∼10 m), from which 5 assemblages were obtained, providing information on the most abundant species of each class supplied by the abiotic study. The second level was carried out considering a management approach and was based on the modeling of the area at lower resolution, more suitable for the analysis of the habitat-fisheries interactions. Thus, the main habitat-forming species (HFS) of the entire circalittoral area were used to perform delta models based on GAMs (Generalize Additive Models). Obtaining the predictions of presence/absence and combining it with the predictions of densities, we got the zero inflated values density-based model. As all the identified habitats have vulnerable benthic species of a certain size settled on rocky bottoms, they can all be considered to belong to the designation 1170 reefs of the Habitats Directive.

Innovations in Coastline Management With Natural and Nature-Based Features (NNBF): Lessons Learned From Three Case Studies

Coastal communities around the world are facing increased coastal flooding and shoreline erosion from factors such as sea-level rise and unsustainable development practices. Coastal engineers and managers often rely on gray infrastructure such as seawalls, levees and breakwaters, but are increasingly seeking to incorporate more sustainable natural and nature-based features (NNBF). While coastal restoration projects have been happening for decades, NNBF projects go above and beyond coastal restoration. They seek to provide communities with coastal protection from storms, erosion, and/or flooding while also providing some of the other natural benefits that restored habitats provide. Yet there remain many unknowns about how to design and implement these projects. This study examines three innovative coastal resilience projects that use NNBF approaches to improve coastal community resilience to flooding while providing a host of other benefits: 1) Living Breakwaters in New York Harbor; 2) the Coastal Texas Protection and Restoration Study; and 3) the South Bay Salt Pond Restoration Project in San Francisco Bay. We synthesize findings from these case studies to report areas of progress and illustrate remaining challenges. All three case studies began with innovative project funding and framing that enabled expansion beyond a sole focus on flood risk reduction to include multiple functions and benefits. Each project involved stakeholder engagement and incorporated feedback into the design process. In the Texas case study this dramatically shifted one part of the project design from a more traditional, gray approach to a more natural hybrid solution. We also identified common challenges related to permitting and funding, which often arise as a consequence of uncertainties in performance and long-term sustainability for diverse NNBF approaches. The Living Breakwaters project is helping to address these uncertainties by using detailed computational and physical modeling and a variety of experimental morphologies to help facilitate learning while monitoring future performance. This paper informs and improves future sustainable coastal resilience projects by learning from these past innovations, highlighting the need for integrated and robust monitoring plans for projects after implementation, and emphasizing the critical role of stakeholder engagement.

Antimicrobial Activity of Lipid Extracts of Echinoderms in the Nhatrang Bay (South China Sea)

The obtained results on the study of the antimicrobial activity of lipid extracts of tissues of starfishes Linckia laevigata and Culcita novaeguineae and sea urchin Diadema setosum collected in the Nhatrang Bay (South China Sea) against nosocomial strains of Klebsiella pneumoniae, Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa, Candida sp., Streptococcus pyogenes, and Staphylococcus aureus are presented. The effect of the investigated extracts on Gram-positive, Gram-negative microorganisms, as well as yeast of the genus Candida, was determined. It was found that lipid extracts of echinoderms of the Nhatrang Bay exhibit the highest antimicrobial activity against the Gram-positive microorganisms, namely Streptococcus pyogenes.

Native Villages of La Salle's Illinois Country

Native Villages of La Salle's Illinois Country

Diversity and habitat preferences of benthic diatoms from South Bay (Livingston Island, Antarctica)

Background and aims – Despite a long research history, knowledge of Antarctic marine benthic diatoms is fragmentary. This study reports on marine benthic diatoms from South Bay, Livingston Island, focusing on diatoms living on hard substrata, and species distribution across different coastal habitats.Material and methods – Samples were collected from tidal pools (19), intertidal cobbles (9), artificial substrata installed at various depths (10), coastal rocks (2), and bottom sediments at depths > 20 m (2). Species identifications and community analyses were done using LM with additional information obtained using SEM. nMDS based on diatom abundance data was applied to display differences between the samples by habitat/substratum type and sampling month. The significance of the habitat/substratum type and sampling month on diatom communities was checked with PERMANOVA. Similarity/dissimilarity within and between sample groups and their contributing species were explored with SIMPER.Key results – In total, 133 diatom taxa were recorded, of which 110 are benthic. A large number of taxa could not be certainly identified. Taxonomic remarks and ecology and distribution data for some rarely reported species with convoluted taxonomic and nomenclatural histories are given. One new combination is proposed. Diatom communities were influenced by the habitat/substratum type, but not by seasonality. Significant differences existed between communities in tidal pools and those on cobbles, artificial substrata, and sediments, and between those on sediments and artificial substrata. Navicula aff. perminuta dominated on cobbles and often on artificial substrata. Species forming mucilage tubes, tree-like colonies, and chains of cells embedded in mucilage were restricted to tidal pools.Conclusion – Benthic diatom communities from South Bay are highly diverse and species show distinct distributions in the coastal habitats, but the scarce studies and often confusing nomenclature history of the taxa make their identification challenging, and potentially common species for the region remain unknown.

TECTONOSTRATIGRAPHIC EVOLUTION AND HYDROCARBON PROSPECTIVITY SOUTH OF GWADAR BAY, MAKRAN ACCRETIONARY WEDGE, OFFSHORE SW PAKISTAN

The Makran accretionary wedge developed as a result of subduction of the Arabian Plate beneath the southern margin of Eurasia since the Eocene. Interpretation of 2D seismic profiles calibrated to offshore well data in a study area to the south of Gwadar Bay (SW Pakistan) indicates a major period of accretion from the mid‐Miocene, as evidenced by the occurrence of thick growth strata associated with large‐scale imbricate thrusts. The thrust faults originate from a deep detachment within the mud‐rich Oligocene interval, and well‐developed piggy‐back basin successions occur in thrust hanging walls. In the study area, the thrust structures are sealed by a thick, progradational Pliocene to Recent interval in which the presence of submarine canyons, up to 2.5 km across, indicate that sedimentary transport was from the north.Fluid escape pipes and associated amplitude anomalies are observed in the seismic profiles studied and may be related to upward migration of thermogenic hydrocarbons from depth, as heavy hydrocarbon fractions <C3 have been reported from nearby wells. The hydrocarbons are believed to have been sourced from the Oligocene Hoshab Shale and to have then migrated up through a sedimentary succession in which permeability barriers are largely absent. Hanging wall anticlines mapped in the study area could provide structural traps, and turbidites in the Lower Miocene Panjgur Formation may represent a potential reservoir. Amplitude anomalies are also observed adjacent to shallow fluid escape pipes within the topsets of clinoforms in the Pleistocene Chatti and Omara Formations, and probably indicate the presence of biogenic hydrocarbons sourced from distal mudstones in bottomset strata.

Post-Hurricane Sandy Benthic Habitat Mapping at Fire Island National Seashore, New York, USA, Utilizing the Coastal and Marine Ecological Classification Standard (CMECS)

In 2012, Hurricane Sandy created a new tidal inlet at Fire Island National Seashore (FIIS) in New York, USA, consequently altering environmental conditions within Great South Bay. This event presented a unique opportunity to establish new ecological baselines, assess resulting ecological change, and explore management implications. This study focuses on benthic mapping within the bayside of FIIS using acoustic, grab sample, and imagery data. Biotope (habitat) maps were developed describing relationships between macrofaunal communities and their environment. Additionally, biotopes were prioritized by “ecological value” based on user-defined criteria (presence of seagrass and potential for higher trophic level interactions) to guide management. While there are limited pre-Sandy data for comparison, findings from this study suggest the inlet has been a positive ecological influence on the nearby area. Dense concentrations of mature blue mussels (Mytilus edulis) documented near the inlet are considered ecologically beneficial and represent a post-Sandy distinction in ecosystem structure; M. edulis was last common when the inlet was previously open (early 1800s). The inlet is also likely responsible for seagrass expansion near the inlet but decline in other areas. This study advances the utility of the Coastal and Marine Ecological Classification Standard (CMECS) by including CMECS-defined data in analyses and expanding the definition of “dominance.” CMECS played a key role in developing map units, interpreting biotopes, and establishing statistically significant and ecologically meaningful biotic–abiotic relationships. This study also highlights the value and management applications of benthic mapping specific to FIIS and more broadly and advocates for similar studies elsewhere.

Interannual crisscross pattern observed in South Asian monsoon rainfall and its relationship with aerosols

This study examines the interannual variability of South Asian summer monsoon rainfall (SAMR) using a linear trend analysis for the recent 17-year period from 2000 to 2016. The trends in SAMR analyzed from multiple rainfall datasets show a unique crisscross like pattern over South Asia and its surrounding oceans. Significant positive trends in SAMR occur over the middle and south Bay of Bengal (BOB) and North-West India (NWI) aligned in SE-NW direction. Similarly, significant negative trends are observed over North-East India and head Bay of Bengal (NEI) as well as over the middle and south Arabian Sea (AS) oriented in SW-NE direction. Western Ghats make an exception to this pattern, where significant positive trends have been observed. Interestingly, the trends in aerosol optical depth (AOD) for the same period closely follow the trends in SAMR. The relationship of AOD averaged over each of the significant aerosol trend regions with the SAMR suggest aerosol induced suppression in moisture transport from a region covering Southern Arabian Sea and Bay of Bengal played a dominant role over the negative trend regions. However, the decreased aerosols over the Northwest India due to significant positive trends in rainfall reduced dust transport from the Arabian Peninsula towards eastern parts of South Asia resulting in an increase in anthropogenic aerosols from local sources. This caused significant drying over the NEI and AS regions through aerosol indirect effects. Further, Aerosol direct radiative effects due to natural and anthropogenic sources inferred from the climate forcing estimates confirmed their role in positive trends and the indirect effects inferred from satellite cloud products depicted a strong association with negative trends, thus maintaining the observed crisscross pattern.

Swell Conditions at Potential Sites for the Colombian Antarctic Research Station

The objective of this paper was to characterize swell conditions in the coastal zone of the South Shetland Islands, where our preliminary analyses evaluated potential locations for the Colombian scientific station. The Simulating Waves Nearshore (SWAN) spectral model was implemented for the Bransfield Strait. The boundary conditions were selected by a cluster analysis of the wave climate from global hindcasting obtained with the WAVEWATCH III model. Some comparisons between the model and wavemeter measurements were made. The results demonstrated that optimal sea state conditions for the scientific base are present in the South Bay, Livingston Island.

Spatio‐temporal distribution and genetic mechanism of Paleogene extension amounts in the Liaodong Bay, Bohai Bay Basin

Based on seismic interpretation of 18 regional 3D high‐resolution seismic sections across Liaodong Bay, extension amounts, extension rates and extension coefficients of different seismic sections from the south to the north are calculated by employing balanced section technique. Then, spatio‐temporal distribution of extension amounts is characterized and interpreted. Finally, the analysis of genetic mechanism is conducted and analysed. The results indicate that tectonic evolution in the Paleogene of Liaodong Bay is characterized by episodic extension. Furthermore, spatio‐temporal distribution of extension amounts is relatively uneven. In terms of space, extension amounts are mainly caused by extensional displacement of main depression‐controlled boundary faults and syn‐depositional faults in the depression. In addition, extensional amounts along main depression‐controlled boundary faults are characterized by larger displacement. In terms of time, the periods for horizontal extensional movement can be divided into three stages: The Palaeocene‐Early Eocene (Kongdian Formation‐third member of Shahejie Formation), Middle‐Late Eocene‐Early Oligocene (first and second member of Shahejie Formation) and Middle‐Late Oligocene (Dongying Formation). Among them, extension during the Palaeocene‐Early Eocene occurs both in the north and south of Liaodong Bay. However, extension intensity in the north is stronger than that in the south. Extension intensity in the middle and north during Middle‐Late Eocene‐Early Oligocene obviously increases. In contrast, it is dominated by strike‐slip movement during depositional period of Dongying Formation. Therefore, extension intensity is characterized by significant inheritance. Spatial–temporal distribution of extension amounts is predominantly controlled by tectonic evolution and associated tectonic deformation.

Diatom communities on an artificial substratum at two contrasting sites at South Bay, Livingston Island

Diatom communities on an artificial substratum at two contrasting sites at South Bay, Livingston Island

Variability in Host Specificity and Functional Potential of Antarctic Sponge-Associated Bacterial Communities.

Sponge-associated microorganisms are essential for sponge survival. They play an important role in recycling nutrients and, therefore, in the maintenance of the ecosystem. These microorganisms are diverse, species-specific, and different from those in the surrounding seawater. Bacterial sponge symbionts have been extensively studied in the tropics; however, little is known about these microorganisms in sponges from high-latitude environments. Sponges can cover up to 80% of the benthos in Antarctica and are crucial architects for the marine food web. In this study, we present analyses of the bacterial symbionts of three sponges: Haliclona (Rhizoniera) sp., Hymeniacidon torquata, and Isodictya kerguelenensis from the Western Antarctic Peninsula (WAP) with the aim to determine variations on the specificity of the bacteria–sponge interactions and potential signatures on their predicted functional profiles. We use high-throughput 16S rRNA gene sequencing of 30 sponge individuals inhabiting South Bay (Palmer Archipelago, WAP) to describe their microbiome taxonomy and diversity and predict potential functional profiles based on this marker gene. Our work shows similar bacterial community composition profiles among the same sponge species, although the symbiotic relationship is not equally conserved among the three Antarctic sponges. The number of species-specific core operational taxonomic units (OTUs) of these Antarctic sponges was low, with important differences between the total abundance accounted for these OTUs. Only eight OTUs were shared between the three sponge species. Analyses of the functional potential revealed that despite the high host–symbiont specificity, the inferred functions are conserved among these microbiomes, although with differences in the abundance of specific functions. H. torquata showed the highest level of intra-specificity and a higher potential of pathways related to energy metabolism, metabolisms of terpenoids and polyketides, and biosynthesis of other secondary metabolites. Overall, this work shows variations in the specificity of the sponge-associated bacterial communities, differences in how hosts and symbionts establish their relations, and in their potential functional capabilities.

Monarchs Reared in Winter in California Are Not Large Enough to Be Migrants. Comment on James et al. First Population Study on Winter Breeding Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) in the Urban South Bay of San Francisco, California. Insects 2021, 12, 946.

A recent study in this journal aimed to understand certain changes in the wintering behavior of monarch butterflies, specifically in the western subpopulation of North America [...].

Reply to Davis, A.K. Monarchs Reared in Winter in California Are Not Large Enough to Be Migrants. Comment on "James et al. First Population Study on Winter Breeding Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) in the Urban South Bay of San Francisco, California. Insects 2021, 12, 946".

This is a reply to the comment from Davis [...].

Abstract PO-004: Hot spot analysis of cervical cancer among racial and ethnic minorities in Los Angeles County

Abstract Background: Geospatial analysis of cervical cancer cases traditionally combines all racial and ethnic subgroups when examining patterns of disease distribution. Given the diverse populations of Los Angeles County (LAC), there are likely distinct barriers as well as linguistic needs of cancer preventive care unique to high risk populations. We compared the distribution of clusters of cervical cancer disease for Latinas, African Americans, and Asian Americans/Pacific Islanders (AAPI), the three largest racial/ethnic minority groups in LAC. Methods: We included data for all stages of cervical cancer (only malignant tumors) diagnosed from 2000 to 2018 in LAC separately for Latinas, African Americans, and AAPI from the Los Angeles County Cancer Surveillance Program. Hot spot analyses were performed using the Getis-Ord GI*statistic in ArcGIS to compare the distribution of statistically significant clusters of cervical cancer cases in LAC using a fixed band. Hot and cold spots with less than 11 cases were suppressed to protect patient confidentiality. Results: Results show that the pattern of cervical cancer clustering across racial/ethnic categories varies substantially across LAC. Among Latinas (N=4303), data show hot spots in Central and Eastern Los Angeles as well as the San Fernando Valley; hot spots exist in Hollywood, Mid-City, the South Bay, the San Gabriel foothills, and the Eastern suburbs of Los Angeles for Asians/Pacific Islanders (N=1332); and hot spots emerged in Central and South Los Angeles, Long Beach and Alhambra for African Americans (N=770). Cervical cancer hot spots do not fully coincide with the residential distribution of racial/ethnic groups in LAC based on data from the 5-year American Community Survey (2014-2018), particularly among Latinas. Discussion: Given the marked differences in cervical cancer disease clustering across racial and ethnic populations in LAC, hot spot analyses of these groups should be performed separately. Using appropriate methodologies for modeling the geospatial distribution of cervical cancer has important implications for the effective planning, location, and delivery of culturally and linguistically appropriate vaccination and screening interventions to address the diverse cervical cancer prevention needs of different communities in LAC. Citation Format: Bibiana M. Martinez, Laura Thompson, Myles Cockburn, Jennifer Tsui. Hot spot analysis of cervical cancer among racial and ethnic minorities in Los Angeles County [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-004.

Mega-City Development Impact on Hourly Extreme Rainfall Over the South China Great Bay Area Under Near-Future Climate Warming

Mega-City Development Impact on Hourly Extreme Rainfall Over the South China Great Bay Area Under Near-Future Climate Warming

Contribution of Wind Speed and Sea-Air Humidity Difference to the Latent Heat Flux-SST Relationship

This study investigates contributions of wind speed and sea-air humidity difference ( dq ) terms to the seasonal change and time scale dependence in the relationship between surface latent heat flux (LHF) and sea surface temperature (SST) using daily data. Generally, the dq term is dominant in the SST effect on LHF in the midlatitude SST frontal zones and tropical Indo-western Pacific, and the wind speed term is dominant in the LHF effect on SST in the subtropical gyres and tropical Indo-western Pacific. The seasonal change in the dq term accounts for a larger SST effect in winter than in summer in the midlatitude frontal zones, and that of the wind speed term explains a larger LHF effect in summer than in winter in the subtropical gyres. In the tropical Indo-western Pacific, the dq term is dominant in the SST effect in summer, and the wind speed term is dominant in the LHF effect in winter. The contribution of the dq term to the SST effect increases with the time scale. The contribution of the wind speed term to the SST effect varies regionally: It is supplementary in the midlatitude frontal zones in winter and summer and in the Arabian Sea in summer, but it is opposite in the Philippine Sea in winter and summer and in the South China Sea and Bay of Bengal in summer. The contribution of the wind speed term to the LHF effect is confined to short time scales in most of the tropical Indo-western Pacific regions.

Comparison of two data acquisition protocols for tide gauge sensors at Imbituba port – Santa Catarina State

The Santa Catarina Tide Gauge Network (SCTGN) is a continuous sea level monitoring system to support fishery, aquaculture, and navigation in general. Deployed in the state of Santa Catarina, Brazil, the initiative started in 2012 with one tide gauge at the Santa Catarina Island South Bay to support aquaculture research projects and hydrodynamic numerical modelling. By 2020, the SCTGN was fully operational, consisting of 11 tide gauge stations along the 450km of the Santa Catarina coastal line. The next step is standardizing these tide stations to international data collection protocols. Knowledge of the effects different programming protocols have on data collection are important since they may affect the results. Data from a radar gauge (RG) and a vented (or relative) pressure gauge (VPG) were obtained over six months. The difference between RG and VPG measurements showed a 5.07cm2 variance. Percentage of reading errors was 0.03% and 0.77% for RG and VPG, respectively. This study aims to evaluate the feasibility of the SCTGN data collection protocol in the RG to comply with the Intergovernmental Oceanographic Commission (IOC) recommendations for sea level monitoring. We find that an RG gauge using the SCTGN protocol is adequate to monitor sea levels and has an easier installation and maintenance, and more stable vertical datum control.

Genetic variation in sea otters (Enhydra lutris) from the North Pacific with relevance to the threatened Southwest Alaska Distinct Population Segment

AbstractFor the sea otter (Enhydra lutris), genetic population structure is an area of research that has not received significant attention, especially in Southwest Alaska where that distinct population segment has been listed as threatened since 2005 pursuant to the U.S. Endangered Species Act. In this study, 501 samples from 14 locations from Prince William Sound, Alaska to the Commander Islands in Russia were analyzed for variation at 13 microsatellite loci. Our results indicate a high degree of genetic divergence among the 14 locations (FST = 0.120) with gene flow conforming to the isolation by distance (IBD) model (r2 = 0.491, p < .05). The 14 sampling locations formed six geographic associations in clustering and ordination analyses that likely correspond to remnant population lineages: (1) Southcentral Alaska, (2) Kodiak and North Alaska Peninsula, (3) South Alaska Peninsula and Bristol Bay, (4) Eastern Aleutian, (5) Western Aleutian, and (6) the Commander Islands. Except for South Alaska Peninsula and Bristol Bay, these clusters closely agree with previously defined stock and management unit boundaries. Our results reveal significant genetic population structure and are generally congruent with current management strategies for the threatened Southwest Alaska distinct population segment.