Biology subjects

Barber, P. H.

Publications and source records attributed to Barber, P. H..

8 recordsLinked to original sources

bioRxiv2022

Message in a Bottle: Archived DNA Reveals Marine Heatwave-Associated Shifts in Fish Assemblages

Marine heatwaves can drive large-scale shifts in marine ecosystems but studying their impacts on whole species assemblages can be difficult. Here, we leverage the taxonomic breadth and resolution of DNA sequences derived from environmental DNA (eDNA) in the ethanol of a set of 23-year longitudinal ichthyoplankton samples, combining these with microscopy-derived ichthyoplankton identification to yield higher-resolution, species-specific quantitative abundance estimates of fish assemblages in the California Current Large Marine Ecosystem during and after the 2014-16 Pacific marine heatwave. This integrated dataset reveals patterns of tropicalization with increases in southern, mesopelagic species and associated declines in important temperate fisheries targets (e.g., North Pacific Hake (Merluccius productus) and Pacific Sardine (Sardinops sagax)). We observed novel assemblages of southern, mesopelagic fishes and temperate species (e.g., Northern Anchovy, Engraulis mordax) even after the return to average water temperatures. Our innovative preservative derived eDNA metabarcoding and quantitative modeling approaches open the door to reconstructing the historical dynamics of assemblages from modern and archived samples worldwide. SummaryNovel quantitative abundance estimates from archived DNA reveals marine heatwave-associated shifts in fish assemblages.

ecology↗

bioRxiv2021

Scoping the Line Up: A Comparison of Biomonitoring Methodologies for Surf Zone Fish Communities

Surf zones are highly dynamic marine ecosystems that are subject to increasing anthropogenic and climatic pressures, posing multiple challenges for biomonitoring. Traditional methods such as seines and hook and line surveys are often labor intensive, taxonomically biased, and can be physically hazardous. Emerging techniques, such as baited remote underwater video (BRUV) and environmental DNA (eDNA) are promising nondestructive tools for assessing marine biodiversity in surf zones of sandy beaches. Here we compare the relative performance of beach seines, BRUV, and eDNA in characterizing community composition of bony (teleost) and cartilaginous (elasmobranch) fishes of surf zones at 18 open coast sandy beaches in southern California. Seine and BRUV surveys captured overlapping, but distinct fish communities with 50% (18/36) of detected species shared. BRUV surveys more frequently detected larger species (e.g. sharks and rays) while seines more frequently detected one of the most abundant species, barred surfperch (Amphistichus argenteus). In contrast, eDNA metabarcoding captured 83.3% (30/36) of all fishes observed in seine and BRUV surveys plus 59 additional species, including 13 that frequent surf zone habitats. eDNA approaches showed significantly higher sensitivity than seine and BRUV methods and more consistently detected 29 of the 30 (96.7%) jointly observed species across beaches. The six species detected by BRUV/seines, but not eDNA either lacked reference sequences, were only resolved at higher taxonomic ranks (e.g. Embiotocidae surfperches), or were detected below occupancy thresholds. Low site-species overlap between methods limited comparisons of richness and abundance estimates, highlighting the challenge of comparing biomonitoring approaches. Despite potential for improvement, results overall demonstrate that eDNA can provide a cost-effective tool for long-term surf zone monitoring that complements data from seine and BRUV surveys, allowing more comprehensive surveys of vertebrate diversity in surf zone habitats.

ecology↗

bioRxiv2021

Firmicutes and Bacteroidetes explain mass gain variation in an obligate hibernator

O_LIBody condition is an important life history challenge that directly impacts individual fitness and is particularly important for hibernating animals, whose maintenance of adequate body fat and mass is essential for survival. C_LIO_LIIt is well documented that symbiotic microorganisms play a vital role in animal physiology and behaviour. Recent work demonstrates that gut microbes are associated with fat accumulation and obesity; Firmicutes is consistently associated with obesity while Bacteroidetes is associated with leanness both in humans and other animals. C_LIO_LIThe focus of most microbiome studies has been on human health or involved lab reared animals used as a model system. However, these microbes likely are important for individual fitness in wild populations and provide potential mechanistic insights into the adaptability and survival of wildlife. C_LIO_LIHere we test whether symbiotic microorganisms within the phyla of Firmicutes and Bacteroidetes are associated with summer mass gain in an exceptionally well-studied wild population of yellow-bellied marmots (Marmota flaviventer) by quantifying microbial abundance over five years of fecal samples (2015 - 2019) collected during their summer active season. C_LIO_LIResults show that marmots with higher mass gain rates have a greater abundance of Firmicutes. In contrast, higher abundance of Bacteroidetes was associated with lower mass gain rates, but only for marmots living in harsher environments. Similar patterns were found at the family level where Ruminococcaceae, a member of Firmicutes, was associated with higher mass gain rates, and Muribaculaceae, a member of Bacteroidetes, was associated with lower mass gain rates, and similarly in harsher environments. C_LIO_LIAlthough correlative, these results highlight the importance of symbiotic gut microbiota to mass gain in the wild, a trait associated with survival and fitness in many taxonomic groups. C_LI

microbiology↗

bioRxiv2021

Seascape genomics reveals population structure and local adaptation in a widespread coral reef snail, Coralliophila violacea (Kiener, 1836)

Local adaptation to different environments may reinforce neutral evolutionary divergence, especially in populations in the periphery of a species geographic range. Seascape genomics (high-throughput genomics coupled with ocean climate databases) facilitates the exploration of neutral and adaptive variation in concert, developing a clearer picture of processes driving local adaptation in marine populations. This study used a seascape genomics approach to test the relative roles of neutral and adaptive processes shaping population divergence of a widespread coral reef snail, Coralliophila violacea. We collected C. violacea from colonies of their coral host (Porites spp.) at ten locations spanning a large portion of their geographic range. We used RAD-seq to investigate possible local adaptation via genetic-environmental associations with five ocean climate variables. Four genetic partitions were concordant with regions previously observed in mtDNA (Indian Ocean, Coral Triangle, and Hawaiian Islands), with the addition of Vietnam and varying isolation and admixture levels. We identified outlier loci (FDR = 0.10, N = 72) among individual localities and between regions (FDR = 0.10, N = 34), suggesting that some loci are putatively under divergent selection. Association analyses showed that the two strongest drivers of local adaptation were the annual range and mean of sea surface temperature. Populations that experience lower sea surface temperatures at the periphery of C. violaceas geographic range drive these associations. Our results show that local adaptation to different environments likely reinforces neutral divergence, especially in peripheral populations.

evolutionary biology↗

bioRxiv2021

Environmental DNA in a Global Biodiversity Hotspot: Lessons from Coral Reef Fish Diversity Across the Indonesian Archipelago

Indonesia is the heart of the Coral Triangle, the worlds most diverse marine ecosystem. Preserving the biological and economic value of this marine biodiversity requires efficient and economical ecosystem monitoring, yet our understanding of marine biodiversity in this region remains limited. This study uses environmental DNA (eDNA) to survey fish communities across a pronounced biodiversity gradient in Indonesia. A total of 12,939,690 sequence reads of MiFish 12S rRNA from 39 sites spanning 7 regions of Indonesia revealed 4,146 Amplified Sequence Variants (ASVs). Regional patterns of fish diversity based on eDNA broadly conformed to expectations based on traditional biodiversity survey methods, with the highest fish biodiversity in Raja Ampat and generally lower diversity in Western Indonesia. However, eDNA performed relatively poorly compared to visual survey methods in site-by-site comparisons, both in terms of total number of taxa recovered and ability to assign species names to ASVs. This result stands in a stark contrast to eDNA studies of temperate and tropical ecosystems with lower diversity. Analyses show that while sequencing depth was sufficient to capture all fish diversity within individual seawater samples, variation among samples from individual localities was high, and sampling effort was insufficient to capture all fish diversity at a given sampling site. Interestingly, mean ASVs recovered per one-liter seawater was surprisingly similar across sites, despite substantial differences in total diversity, suggesting a limit to total ASVs (~200) per one-liter eDNA sample. Combined, results highlight two major challenges of eDNA in highly diverse ecosystems such as the Coral Triangle. First, reference databases are incomplete and insufficient for effective ASV taxonomic assignment. Second, eDNA sampling design developed from lower diversity temperate marine ecosystems are inadequate to fully capture diversity of biodiversity hotspots like the Coral Triangle.

ecology↗

bioRxiv2020

Investigating temporal and spatial variation of eDNA in a nearshore rocky reef environment

Environmental DNA (eDNA) is increasingly used to measure biodiversity of marine ecosystems. However, key aspects of spatial and temporal dynamics of eDNA remain unknown. Particularly, it is unclear how long eDNA signals persist locally in dynamic marine environments, since degradation rates have predominantly been quantified through mesocosm studies. To determine in situ eDNA residence times, we introduced an eDNA signal from a non-native fish into a Southern California rocky reef ecosystem, and then measured changes in both introduced and background eDNA signals over 96 hours. Foreign eDNA signal could no longer be detected 7.5 hours after introduction, far exceeding disappearance rates quantified in laboratory studies. In addition, native vertebrate eDNA signals varied greatly over the 96 hours of observation, but time of day and tidal direction did not drive this variation in community structure. Species accumulation curves showed that standard sampling protocols using 3 replicate 1 L sea water samples were insufficient to capture full diversity of local marine vertebrates, capturing only 76% of all taxa. Despite this limitation, a single eDNA sample captured greater vertbrate diversity than 18 SCUBA based underwater visual transect surveys conducted at a nearby site. There was no significant difference in species richness between temporal replicates and spatial replicates, suggesting a space for time substitution may be effective for fully capturing the diversity of local marine vertebrate communities in nearshore rocky reef environments. This result is particularly important in designing eDNA metabarcoding sampling protocols to capture local marine species diversity.

ecology↗

bioRxiv2020

MiSebastes: An eDNA metabarcoding primer set for rockfishes (genus Sebastes)

Environmental DNA (eDNA) is a promising biomonitoring tool for marine ecosystems, but its effectiveness for North Pacific coastal fishes is limited by the inability of existing barcoding primers to differentiate among rockfishes in the genus Sebastes. Comprised of 110 commercially and ecologically important species, this recent radiation is exceptionally speciose, and exhibits high sequence similarity among species at standard barcoding loci. Here, we report new Sebastes-specific metabarcoding primers that target mitochondrial cytochrome B. Amongst the 110 Sebastes species, 85 unique barcodes (of which 62 are species-specific) were identified in our amplicon region based on available reference sequences. The majority of the remaining barcodes are shared by only two species. Importantly, MiSebastes yield unique barcodes for 28 of 44 commercially harvested species in California, a dramatic improvement compared to the widely employed MiFish 12S primers which only recover one of 44. Tests of these primers in an aquarium mesocosm containing 16 rockfish species confirms the utility of these new primers for eDNA metabarcoding, providing an important biomonitoring tool for these key coastal marine fishes.

ecology↗

bioRxiv2020

eDNA metabarcoding as a biomonitoring tool for marine protected areas

Monitoring of marine protected areas (MPAs) is critical for marine ecosystem management, yet current protocols rely on SCUBA-based visual surveys that are costly and time consuming, limiting their scope and effectiveness. Environmental DNA (eDNA) metabarcoding is a promising alternative for marine ecosystem monitoring, but more direct comparisons to visual surveys are needed to understand the strengths and limitations of each approach. This study compares fish communities inside and outside the Scorpion State Marine Reserve off Santa Cruz Island, CA using eDNA metabarcoding and underwater visual census surveys. Results from eDNA captured 76% (19/25) of fish species and 95% (19/20) of fish genera observed during pairwise underwater visual census. Species missed by eDNA were due to the inability of MiFish 12S barcodes to differentiate species of rockfishes (Sebastes, n=4) or low site occupancy rates of crevice-dwelling Lythrypnus gobies. However, eDNA detected an additional 30 fish species not recorded in paired visual surveys, but previously reported from prior visual surveys, highlighting the sensitivity of eDNA. Significant variation in eDNA signatures by location (50m) and site (~1000m) demonstrates the sensitivity of eDNA to address key questions such as community composition inside and outside MPAs. Interestingly, eDNA results recorded higher species richness outside the MPA while visual surveys observed the opposite pattern. This result is likely caused by swamping effects of high fish abundance in MPAs that reduce detection probabilities of pelagic and intertidal taxa. Results demonstrate the utility of eDNA metabarcoding for monitoring marine ecosystems, providing an important complementary tool to visual methods.

molecular biology↗