Biology subjects

Neave, E. F.

Publications and source records attributed to Neave, E. F..

5 recordsLinked to original sources

bioRxiv2025

Refining a molecular tool kit to capture tropicalization in Mediterranean Marine Protected Areas

Tropicalization, the process by which tropical species expand their ranges poleward due to global ocean warming, is a prominent threat to Mediterranean marine ecosystems, challenging their effective management and conservation. The arrival of non-indigenous fish is exacerbated by the Suez Canal that allows Indo-Pacific species to enter the region from the Red Sea. While some non-indigenous species (NIS) have already changed the composition and function of native Mediterranean communities, many others continue to arrive but often go unnoticed without regular surveys or until they are strongly established. We conducted biodiversity surveys using underwater visual census (UVC), aqueous environmental DNA (eDNA) and sponge-derived eDNA (i.e., eDNA accumulated in sea sponge tissue) at two protected locations in Zakynthos, Greece. Seven NIS were detected by eDNA, but only one (dusky spinefoot, Siganus luridus) was detected with all three methods. The fish assemblages of the two locations could be distinguished based on both UVC and eDNA but not from sponge-derived eDNA data, perhaps given low filtration rates. Of the three methods, aqueous eDNA metabarcoding provided the most comprehensive species list including new NIS detected (with the red-toothed triggerfish, Odonus niger, and the houndfish, Tylosurus crocodilus, being the first and third record in the Mediterranean Sea, respectively). Our findings highlight the potential value of incorporating molecular methods into regular monitoring as early warning tools for detecting NIS in marine protected areas threatened by ocean warming.

ecology↗

bioRxiv2025

DNA Divers: volunteer-based eDNA capture for local and global marine biodiversity monitoring

Volunteer-based biodiversity recording is a powerful source of scalable data yet to be used to its full potential by the scientific community. Coastal ecosystems are varied and diverse, making it difficult for managers to identify flexible methods for monitoring biological components. Emerging technologies such as environmental DNA (eDNA) analysis are promising for measuring aquatic biodiversity, yet most management organizations lack personnel and capacity to collect molecular data. Here we investigate, together as professional and non-professional scientists, the efficacy of a quasi-passive eDNA capture technique. Volunteer SCUBA divers and snorkelers used low-cost materials, namely cotton medical gauze, to capture eDNA via swimming. We compared this method to conventional eDNA capture techniques in an aquarium and nature, collectively iterating the field and laboratory procedures to improve feasibility. With a small (< 30) network of volunteers, we detected 275 unique teleost and elasmobranch species from varied marine habitats spanning 90 degrees of latitude. The swimming motion of divers was more effective than stationary soaking and the fish communities sampled by divers were comparable to that of conventional eDNA samples. The ease of this technique matched by the eagerness and generosity of volunteers presents an untapped, viable approach for scaling multi-species marine eDNA monitoring as well as an avenue for improving science literacy. Data availabilityhttps://zenodo.org/records/14853820?token=eyJhbGciOiJIUzUxMiJ9.eyJpZCI6ImYxMTlhODFiLTI3NGYtNDQ2Ni05MDYyLTIyOTlkNWVhY2FkNiIsImRhdGEiOnt9LCJyYW5kb20iOiIwYmZlMzJhMWU0YWZkM2ZhMWEwYTE0NmY0ZWM5YWZkNSJ9.0R7GJjVJLEuq-UJVKA1CcMT8LCTamv3GEvPl-5ItzP10pFRd-cAzAr_Q5ggjEewZUtByHjBu-eSegWWlLAx_Rw

ecology↗

bioRxiv2023

Trapped DNA fragments in marine sponge specimens unveil north Atlantic deep-sea fish diversity

Sponges pump water to filter feed and for diffusive oxygen uptake. In doing so, trace DNA fragments from a multitude of organisms living around them are trapped in their tissues. Here we show that the environmental DNA retrieved from archived marine sponge specimens can reconstruct the fish communities at the place of sampling and discriminate North Atlantic assemblages according to biogeographic region (from Western Greenland to Svalbard), depth habitat (80-1600m), and even the level of protection in place. Given the cost associated with ocean biodiversity surveys, we argue that targeted and opportunistic sponge samples - as well as the specimens already stored in museums and other research collections - represent an invaluable trove of biodiversity information that can significantly extend the reach of ocean monitoring.

ecology↗

bioRxiv2022

Optimised DNA isolation from marine sponges for natural sampler DNA (nsDNA) metabarcoding

Marine sponges have recently been recognised as natural samplers of environmental DNA (eDNA) due to their effective water filtration and their ubiquitous, sessile and regenerative nature. However, laboratory workflows for metabarcoding of sponge tissue have not been optimised to ensure that these natural samplers achieve their full potential for community survey. We used a phased approach to investigate the influence of DNA isolation procedures on the biodiversity information recovered from sponges. In Phase 1, we compared three treatments of residual ethanol preservative in sponge tissue alongside five DNA extraction protocols. The results of Phase 1 informed which ethanol treatment and DNA extraction protocol should be used in Phase 2, where we assessed the effect of starting tissue mass on extraction success and whether homogenisation of sponge tissue is required. Phase 1 results indicated that ethanol preservative may contain unique and/or additional biodiversity information to that present in sponge tissue, but blotting tissue dry generally recovered more taxa and generated more sequence reads from the wild sponge species. Tissue extraction protocols performed best in terms of DNA concentration, taxon richness and proportional read counts, but the non-commercial tissue protocol was selected for Phase 2 due to cost-efficiency and greater recovery of target taxa. In Phase 2 overall, we found that homogenisation may not be required for sponge tissue and more starting material does not necessarily improve taxon detection. These results combined provide an optimised DNA isolation procedure for sponges to enhance marine biodiversity assessment using natural sampler DNA metabarcoding.

molecular biology↗

bioRxiv2021

Protistan plankton communities in the Galapagos Archipelago respond to changes in deep water masses resulting from the 2015/16 El Nino

The Galapagos Archipelago lies within the eastern equatorial Pacific Ocean at the convergence of major ocean currents that are subject to changes in circulation. The nutrient-rich Equatorial Undercurrent upwells from the west onto the Galapagos platform, stimulating primary production, but this source of deep water weakens during El Nino events. From measurements collected on repeat cruises, the 2015/16 El Nino was associated with declines in phytoplankton biomass at most sites throughout the archipelago and reduced utilization of nitrate, particularly in large-sized phytoplankton in the western region. Protistan assemblages were identified by sequencing the V4 region of the 18S rRNA gene. Dinoflagellates, chlorophytes, and diatoms dominated most sites. Shifts in dinoflagellate communities were most apparent between the years; parasitic dinoflagellates, Syndiniales, were highly detected during the El Nino (2015) while the dinoflagellate genus, Gyrodinium dominated many sites during the neutral period (2016). Variations in protistan communities were most strongly correlated with changes in subthermocline water density. These findings indicate that marine protistan communities in this region are regimented by deep water mass sources and thus could be profoundly affected by altered ocean circulation.

ecology↗