Morphology is not always useful for diagnosis, and that’s ok: Species hypotheses should not be bound to a class of data. Reply to Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590)

This paper serves as a reply to the Commentary by Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590) on our recently published paper on systematics of the moon jellyfish genus Aurelia (Lawley et al. PeerJ 2021;9, e11954)). We emphasise that we are not advocating for the routine use of molecular data alone in taxonomic diagnoses, rather that it is a valid approach in cases where, after detailed analyses, morphological features are shown to be unreliable

ENSO-Induced Co-Variability of Salinity, Plantkton Biomass and Coastal Currents in the Northern Gulf of Mexico

The northern Gulf of Mexico (GoM) is a region strongly influenced by river discharges of freshwater and nutrients, which promote a highly productive coastal ecosystem that host commercially valuable marine species. A variety of climate and weather processes could potentially influence the river discharges into the northern GoM. However, their impacts on the coastal ecosystem remain poorly described. By using a regional ocean-biogeochemical model, complemented with satellite and in situ observations, here we show that El Niño - Southern Oscillation (ENSO) is a main driver of the interannual variability in salinity and plankton biomass during winter and spring. Composite analysis of salinity and plankton biomass anomalies shows a strong asymmetry between El Niño and La Niña impacts, with much larger amplitude and broader areas affected during El Niño conditions. Further analysis of the model simulation reveals significant coastal circulation anomalies driven by changes in salinity and winds. The coastal circulation anomalies in turn largely determine the spatial extent and distribution of the ENSO-induced plankton biomass variability. These findings highlight that ENSO-induced changes in salinity, plankton biomass, and coastal circulation across the northern GoM are closely interlinked and may significantly impact the abundance and distribution of fish and invertebrates

Chapter 5 A COMPARATIVE REVIEW OF MACROMEDUSAE IN EASTERN BOUNDARY CURRENTS

oceanography, climate change, reefs, marine science, marine conservation, marine researc

A Comparative Review of Macromedusae in Eastern Boundary Currents

Edited By: S. J. Hawkins, A. J. Lemasson, A. L. Allcock, A. E. Bates, M. Byrne, A. J. Evans, L. B. Firth, E. M. Marzinelli, B. D. Russell, I. P. Smith, S. E. Swearer, P. A. Todd.The productive eastern boundary current (EBC) systems provide significant sources of global marine protein and have been subject to intense research over the last 50 years. Yet large jellyfish, which are present in all four major systems, have seldom been included in otherwise comprehensive reviews. This undoubtedly reflects their lack of intrinsic commercial value, and the consequently slow pace of knowledge generation. We attempt to redress that imbalance here and to consolidate disparate information on the macromedusae of EBC systems. With the exception of the Canary Current system, which supports a generally low biomass of mostly subtropical taxa, 372jellyfish assemblages in the Benguela, Humboldt and California Current systems are dominated by cool water taxa that can occur at high abundances. While there are large gaps in knowledge, which are highlighted, it is clear that jellyfish can play significant ecological roles in each system. Although there may be strong similarities in faunal composition among the different systems, there are pronounced differences in population responses to the environment and in system resilience and these are reviewed and discussed.Variously, we would also like to thank the Namibian government for access to data and to the National Research Foundation (South Africa), the Royal Society (London), the EAF Nansen Programme and the University of the Western Cape for financial support over the years. We are grateful to the Chilean government and the Agencia Nacional de Investigación y Desarrollo de Chile – formerly Comisión Nacional de Investigación Científica y Tecnológica, and IMARPE for their financial support, and would like to acknowledge grants awarded by the Inter-American Institute for Global Change Research in Montevideo (GEO-0452325, EXA 470/10, PIP 12-201101-00892; CRN3070), as well as the Ministerio de Ciencia, Tecnología e Innovación Productiva in Argentina (FONCyT 01553, FONCyT PICT 2006 No. 1553). Funding was provided by NOAA Fisheries through the Northwest and Southwest Fisheries Science Centers. The CSIC research was supported by projects P07-RNM-02976 (Junta de Andalucía), CTM2011-22856 (Spanish Ministry of Science and Innovation) and 2019AEP203 (CSIC).Peer reviewe

Functioning of Coastal River-Dominated Ecosystems and Implications for Oil Spill Response: From Observations to Mechanisms and Models

Coastal river-dominated oceans are physically complex, biologically productive, and intimately connected to human socioeconomic activity. The Deepwater Horizon blowout and subsequent advection of oil into coastal waters of the northern Gulf of Mexico (nGOM) highlighted the complex linkages among oceanographic processes within this river-dominated system and knowledge gaps about it that resulted in imprecise information on both oil transport and ecosystem consequences. The interdisciplinary research program implemented through the CONsortium for oil exposure pathways in COastal River-Dominated Ecosystems (CONCORDE) is designed to identify and quantitatively assess key physical, biological, and geochemical processes acting in the nGOM, in order to provide the foundation for implementation of a synthesis model (coupled circulation and biogeochemistry) of the nGOM shelf system that can ultimately aid in prediction of oil spill transport and impacts. CONCORDE field and modeling efforts in 2015–2016 focused on defining the influence of freshwater input from river plumes in the nGOM. In situ observations, combined with field-deployed and simulated drifters, show considerable variability in the spatial extent of freshwater influence that is related to wind direction and strength. Increased primary production and particle abundance (a proxy for secondary production) was observed during the spring when nGOM shelf waters were becoming stratified. Zooplankton and marine snow displayed intense vertical and horizontal patchiness during all seasons, often aggregating near the halocline. Simulations of a neutrally buoyant tracer released offshore of the Mississippi Bight showed surface advection of low tracer concentrations onto the inner shelf under high river discharge, high stratification, and variable wind conditions compared to almost no advection onto the inner shelf under low discharge, negligible stratification, and generally northeasterly winds. The interconnectedness of environmental variables and biological activity indicate that multiple factors can affect the transport of oil and the resulting ecological impacts. The process-oriented understanding provided by CONCORDE is necessary to predict ecosystem-level impacts of oil spills, and these results are applicable to other river-dominated coastal systems worldwide that often support oil extraction activities

Morphological Plasticity In \u3ci\u3eAurelia\u3c/i\u3e Polyps, With Subsequent Effects On Asexual Fecundity and Morphology of Young Medusae

© Inter-Research 2017. A key step toward better knowledge of the causes and mechanisms of mass occurrences (blooms) in scyphozoan jellyfish is to assess the extent of environmentally induced effects on the phenotype of different phases in their complex life cycle. Laboratory experiments were carried out to quantify the extent of environmentally induced changes in Aurelia sp.9 polyp morphology, and subsequent effects on asexual propagation and ephyra morphology, in response to temperature and food quantity. Size and shape of polyps was highly plastic to environmental variation, and environmentally induced morphology had a significant effect on asexual fecundity and propagation strategy. Polyp size positively correlated with the number of buds, new polyps, and ephyrae produced per polyp, but negatively correlated with investment per bud. Environmentally induced polyp morphology had a significant effect on the morphology of ephyra at release. These findings suggest that asexual fecundity in Aurelia sp.9 polyps is likely ultimately limited by body size, which can be environmentally mediated. This work also shows, for the first time, that polyp and ephyra traits are linked. Environmentally induced variation in polyp morphology can be carried into the next life-cycle phase and affect the morphology of ephyrae at release. We conclude that environmentally induced effects on polyp morphology can potentially control the number of new polyps produced, as well as the number of medusae released into the water column. Hence, in scyphozoan jellyfish, metamorphosis is not necessarily a new beginning, and environmental conditions experienced by the polyp can have a significant effect on traits of subsequent phases

Local versus Generalized Phenotypes in Two Sympatric \u3ci\u3eAurelia\u3c/i\u3e Species: Understanding Jellyfish Ecology Using Genetics and Morphometrics

For individuals living in environmentally heterogeneous environments, a key component for adaptation and persistence is the extent of phenotypic differentiation in response to local environmental conditions. In order to determine the extent of environmentally induced morphological variation in a natural population distributed along environmental gradients, it is necessary to account for potential genetic differences contributing to morphological differentiation. In this study, we set out to quantify geographic morphological variation in the moon jellyfish Aurelia exposed at the extremes of a latitudinal environmental gradient in the Gulf of Mexico (GoM). We used morphological data based on 28 characters, and genetic data taken from mitochondrial cytochrome oxidase I (COI) and nuclear internal transcribed spacer 1 (ITS-1). Molecular analyses revealed the presence of two genetically distinct species of Aurelia co-occurring in the GoM: Aurelia sp. 9 and Aurelia c.f. sp. 2, named for its divergence from (for COI) and similarity to (for ITS-1) Aurelia sp. 2 (Brazil). Neither species exhibited significant population genetic structure between the Northern and the Southeastern Gulf of Mexico; however, they differed greatly in the degree of geographic morphological variation. The morphology of Aurelia sp. 9 exhibited ecophenotypic plasticity and varied significantly between locations, while morphology of Aurelia c.f. sp. 2 was geographically invariant (i.e., canalized). The plastic, generalist medusae of Aurelia sp. 9 are likely able to produce environmentally-induced, “optimal” phenotypes that confer high relative fitness in different environments. In contrast, the non-plastic generalist individuals of Aurelia c.f. sp. 2 likely produce environmentally-independent phenotypes that provide the highest fitness across environments. These findings suggest the two Aurelia lineages co-occurring in the GoM were likely exposed to different past environmental conditions (i.e., different selective pressures) and evolved different strategies to cope with environmental variation. This study highlights the importance of using genetics and morphometric data to understand jellyfish ecology, evolution and systematics

Diminished Fitness In an Endemic Hawaiian Snail In Nonnative Host Plants

© 2016 Dipartimento di Biologia, Università di Firenze, Italia. Hawaii’s diverse achatinellid tree snails occur almost exclusively in host trees and shrubs that are native to the Hawaiian Archipelago. A few exceptions to this pattern are known, where an arboreal gastropod population has persisted in introduced plants. On Oahu, Hawaii, the last known population of the single-island endemic snail Auriculella diaphana has persisted in nonnative plants for multiple decades, leading to the following question: are there differences in the relative fitness of native gastropods in native versus nonnative host plants? To address this we conducted laboratory trials with A. diaphana in three treatment groups, one with the two dominant nonnative host plants from their current distribution, another group with two primary native host plant species, and a third treatment maintained in cages with a mixture of equal parts of both the nonnative and native plants. Trials were replicated in two 16-week intervals, with 100 snails. Relative fitness was assessed among treatments as survival and reproductive output (number of eggs produced). Results demonstrated that while survival of adult snails was equivalent across treatments (100%), fecundity was significantly higher in cages where native plants were available. Egg production was 20.05-fold and 14.95-fold greater in treatments with 100% and 50% native host plants, respectively, than in treatments with nonnative plants only. These results suggest that native snails persisting in nonnative host plants experience sublethal stress, reflected in a dramatic reduction in reproductive output. Snails in treatments with mixed native and nonnative plants also showed significantly higher reproduction than those in nonnative plant cages. We suggest that the observed decreased fecundity was due to the poor nutritional value of the microbial phyllosphere of nonnative vegetation, and that translocation of this and related species occurring in nonnative habitat to nearby native host plants will be beneficial in terms of relative fitness

Parasites Alter Behavior, Reproductive Output, and Growth Patterns of \u3ci\u3eAurelia\u3c/i\u3e Medusae In a Marine Lake

Parasites are known to induce phenotypic modifications in their hosts through direct competition for resources, which can negatively affect host fitness. Although parasite-induced phenotypic variation has been studied extensively in terrestrial and freshwater taxa, this phenomenon remains comparatively under-studied in marine pelagic invertebrates, such as ecologically important jellyfish. Here we studied the parasite-host relationship between Edwardsiella sp. anemone larvae (parasite) and medusae of Aurelia sp. 5 (host) in an isolated marine lake (Veliko Jezero) in Croatia. During 3 different seasons, we quantified differences in the vertical position in the water column, morphology, and egg production between parasitized and unparasitized medusae. Our results revealed that medusa behavior, morphology, and fecundity can be significantly affected by parasitism. Infected medusae were more abundant higher in the water-column where water was warmer, while unparasitized individuals displayed the opposite pattern. In addition, host somatic growth, gonad size, and egg production were negatively affected by parasitism, suggesting an ultimate negative effect on medusa fecundity. Parasitized individuals, however, developed relatively longer manubria and produced larger eggs than unparasitized counterparts, indicating a compensatory response to increase capture surface and reproductive effort. This study demonstrates the extent of parasite-induced phenotypic variation in jellyfish as well as the role of parasites in potential regulation of jellyfish population size

Correction: Local versus Generalized Phenotypes in Two Sympatric Aurelia Species: Understanding Jellyfish Ecology Using Genetics and Morphometrics.

[This corrects the article DOI: 10.1371/journal.pone.0156588.]