Marine Invasions Research

Principal Investigator

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Biological invasions - the establishment of species beyond their historical range - are a major force of ecological and evolutionary change. Our lab aims to understand the patterns, processes, and consequences of invasions in marine ecosystems on local to global scales.  We have laboratories and staff on both coasts of North America, on Chesapeake Bay and San Francisco Bay (Tiburon Lab).  These bays are focal points for our long-term, intensive research, which spans Pacific and Atlantic shorelines of the Americas --- from polar to tropical latitudes. 

Most marine invasions result from human-mediated species transfers, which are often associated with commercial and recreational vessels. A major component of our research examines shipping, transportation, and trade dynamics for the United States with the National Ballast Information Clearinghouse (NBIC), a joint program with the U.S. Coast Guard that is based at SERC.  NBIC tracks the status and trends of ballast water delivery and management for the Nation.

Our research encompasses a wide range of projects, exploring the ecology and management of coastal marine ecosystems.  We focus primarily on invasion dynamics but also examine species interactions of both native and non-native species. Overall, we seek to: (1) characterize patterns of marine invasion across space, time, and taxonomic groups; (2) develop a mechanistic understanding of the processes that drive observed patterns; (3) advance predictive capability about the establishment, spread, and impacts of non-native species in marine ecosystems; (4) evaluate the efficacy of management strategies to limit the establishment and impact of invaders; and (5) understand the roles of species interactions, including predator-prey and host-parasite relationships, in marine communities. 

Further details on the various dimensions of our work are available below. 

Wasson, K., Fabian, R.A., Fork, S., Stanganelli, J., Mize, Z., Beheshti, K., Jeppesen, R., Jones, I.J., Zabin, C.J, Walker, S., Lummis, S.C., Emery, M., Moore, J.D., Endris, C., Jolette, D., and Byers, J.E.  2020. Multiple factors contribute to the spatially variable and dramatic decline of an invasive snail in an estuary where it was long-established and phenomenally abundant. Biol Invasions. doi:10.1007/s10530-019-02172-w  (online January 22, 2020)

Pagenkopp Lohan, K.M., DiMaria, R., Martin, D.L., Ross, C., and Ruiz, G.M. 2020. Diversity and microhabitat associations of Labyrinthula spp. in the Indian River Lagoon System. Dis Aquat Org 137:145-157. (online January 16, 2020)

Parretti, P., Canning-Clode, J., Mendes, A.B., and Costa, A.C. 2019Who, why and how: stakeholder attitudes toward marine non-indigenous species management in Portuguese Atlantic Islands. Ocean and Coastal Management. (online December 18, 2019

Haram, L.E., Carlton, J.T., Ruiz, G.M., and Maximenko, N.A. 2019. A Plasticene lexicon. Marine Pollution Bulletin. (Online November 18, 2019).

Miller, A.W., Reynolds, A.C., Minton, M.S. 2019. A spherical falling film gas-liquid equilibrator for rapid and continuous measurements of CO2 and other trace gases. PLOS ONE (Online September 25, 2019)


January 22, 2020

Wasson, K., Fabian, R.A., Fork, S., Stanganelli, J., Mize, Z., Beheshti, K., Jeppesen, R., Jones, I.J., Zabin, C.J, Walker, S., Lummis, S.C., Emery, M., Moore, J.D., Endris, C., Jolette, D., and Byers, J.E.  2020. Multiple factors contribute to the spatially variable and dramatic decline of an invasive snail in an estuary where it was long-established and phenomenally abundant. Biol Invasions. doi:10.1007/s10530-019-02172-w  

Boom-bust dynamics of invasive species have long intrigued scientists and managers alike, but quantification of such dynamics, let alone their causes, is rare. We documented the decline of a previously prolific invasive mudsnail, Batillaria attramentaria, at Elkhorn Slough estuary in central California, USA. The mudsnail was the most abundant epibenthic invertebrate in the estuary, maintaining very high densities for many decades before declining heterogeneously throughout the estuary over the past decade, decreasing in density by three orders of magnitude at some sites. We used field and laboratory experiments to test several possible mechanisms for its demise. We show that the crab Pachygrapsus crassipes can prey heavily on Batillaria. We detected high dissolution rates of Batillaria shells, and we measured greater predation rates on tethered snails with dissolved versus intact shells. Warm water temperatures and high water levels coincided with the period of most dramatic Batillaria declines (2013–2015). Localized water impoundments appear to buffer environmental drivers of the decline because Batillaria remained abundant at sites with artificial tidal restriction, while the population crashed at one site after full tidal exchange was restored. We also investigated trematode parasite prevalence and molluscicide applications to the surrounding watershed as possible causes of mudsnail declines, but they had little explanatory power. Our findings illustrate the potential for population crashes even for long-established introduced species at pest levels of abundance, and demonstrate that such declines can exhibit spatial heterogeneity. Both of these results highlight the value of investigating population dynamics of invaders across multiple temporal and spatial scales.

January 16, 2020

Pagenkopp Lohan, K.M., DiMaria, R., Martin, D.L., Ross, C., and Ruiz, G.M. 2020Diversity and microhabitat associations of Labyrinthula spp. in the Indian River Lagoon System. Dis Aquat Org 137:145-157. 

Seagrasses create foundational habitats in coastal ecosystems. One contributing factor to their global decline is disease, primarily caused by parasites in the genus Labyrinthula. To explore the relationship between seagrass and Labyrinthula spp. diversity in coastal waters, we examined the diversity and microhabitat association of Labyrinthula spp. in 2 inlets on Florida’s Atlantic Coast, the Indian River Lagoon (IRL) and Banana River. We used amplicon-based high throughput sequencing with 2 newly designed primers to amplify Labyrinthula spp. from 5 seagrass species, water, and sediments to determine their spatial distribution and microhabitat associations. The SSU primer set identified 12 Labyrinthula zero-radius operational taxonomic units (ZOTUs), corresponding to at least 8 putative species. The ITS1 primer set identified 2 ZOTUs, corresponding to at least 2 putative species. Based on our phylogenetic analyses, which include sequences from previous studies that assigned seagrass-related pathogenicity to Labyrinthula clades, all but one of the ZOTUs that we recovered with the SSU primers were from non-pathogenic species, while the 2 ZOTUs recovered with the ITS1 primers were from pathogenic species. Some of the ZOTUs were widespread across the sampling sites and microhabitats (e.g. SSU ZOTU_10), and most were present in more than one site. Our results demonstrate that targeted metabarcoding is a useful tool for examining the relationships between seagrass and Labyrinthula diversity in coastal waters.

December 18, 2019

Parretti, P., Canning-Clode, J., Mendes, A.B., and Costa, A.C. 2019Who, why and how: stakeholder attitudes toward marine non-indigenous species management in Portuguese Atlantic Islands. Ocean and Coastal Management.

A key aspect for a successful management of marine non-indigenous species (NIS) is the cooperation with local stakeholders. In this study we assessed stakeholders' baseline knowledge and perceptions on marine NIS foreseeing support for their management in the Azores and Madeira archipelagos (Portugal). Survey questionnaires were designed to assess: i) current knowledge and stakeholder perception of NIS and associated problems; ii) influence of communication media on NIS dissemination; iii) stakeholder willingness to be involved in NIS management actions and; iv) which factors predict stakeholder participation in NIS management actions. Face-to face survey questionnaires were administered in recreational marinas of São Miguel (Azores) and Madeira islands. Four groups of stakeholders classified based on their putative relation with NIS were selected as target. In total 214 survey questionnaires were collected and analysed. Our results showed no significant differences between stakeholders based in São Miguel and the ones from Madeira. Overall a strong baseline knowledge on NIS and associated consequences was found but a weak accuracy to identify NIS examples was demonstrated. Types of communication media revealed to be stakeholder-specific and information-specific. Decision tree predictive models showed three powerful factors to forecast the respondent's participation in NIS management actions: 1- to belong to one of the four stakeholder groups; 2- to have a good level of NIS knowledge; and 3- to have the perception that NIS introduction is an important issue. Despite the positive attitude exhibited by stakeholders in engaging NIS management, our results highlighted a consensus to attribute governmental responsibility to such activities. The results of this work constitute a baseline to develop further management actions aiming to reduce the local spread of marine NIS and so contributing to a better environmental status of Portuguese marine waters.

November 18, 2019

Haram, L.E., Carlton, J.T., Ruiz, G.M., and Maximenko, N.A. 2019. A Plasticene lexicon. Marine Pollution Bulletin. 

As plastic pollution in the environment has increased rapidly in the last half century, so too has the study of the effects of plastic on marine, aquatic and terrestrial ecosystems. From this research, a series of new terms has emerged to describe the phenomena unique to the presence of plastic-based materials in nature. In this short note, we bring together disparate neologisms into a single lexicon with the aim to encourage use of a unified vocabulary to describe the new reality of ecological, chemical, and geological systems in the age of plastics.

September 25, 2019

Miller, A.W.Reynolds, A.C.Minton, M.S. 2019. A spherical falling film gas-liquid equilibrator for rapid and continuous measurements of CO2 and other trace gases. PLOS ONE

Use of gas-liquid equilibrators to measure trace gases such as CO2, methane, and radon in water bodies is widespread. Such measurements are critical for understanding a variety of water quality issues such as acidification due to elevated CO2 or other processes related ecosystem metabolism and function. However, because gas-liquid equilibrators rely on generating sufficient surface area for gas exchange between liquid and gas phases, most traditional equilibrators pass water through small orifices or interstitial spaces that rapidly clog in highly productive or turbid waters, conditions that are common in estuaries, coastal bays, and riverine systems. Likewise, in cold temperatures, such equilibrators are subject to freezing. Both situations lead to failure and limit utility, especially for long term, continuous environmental monitoring. Here we describe and test a gas-liquid equilibrator that relies on a continuous falling film of water over a spherical surface to drive gas exchange. Our results demonstrate that this design is accurate in its ability to equilibrate fully to aqueous CO2 concentrations, is functional across a wide range of gas concentrations, and has a response time that is comparable with other equilibrator designs. Because this equilibrator uses free flowing, falling water to produce a surface for gas exchange, our field trials have shown it to be very resistant to clogging and freezing, and therefore well suited to long term deployment in highly productive waters like estuaries where CO2 concentrations fluctuate hourly, daily, and seasonally. When generated across a spherical surface, the falling film is not adversely affected by tilting off vertical, conditions that are common on a ship, small vessel, or buoy.​


Species distributions are at the core of all ecological and evolutionary processes. Despite recognition that accelerating invasions are radically changing fundamental ecological processes, we currently lack the data for a broad scale understanding of these  patterns, emergent properties, and practical implications across both spatial and temporal scales. We are collecting quality occurrence data and using these data to understand patterns and mechanisms of invasion, and making these data publicly available for broader application by the public.

Our Projects

The impacts of introduced species pose significant challenges for conservation and restoration because they undermine a desired outcome for target species or habitats. In addition, some invasions impose significant economic costs through loss of agriculture, forestry, and fisheries products, and others, including mosquito-borne viruses and toxic algal blooms, have severe human health effects. Detailed analysis of several high-profile species invasions have highlighted the types and potential magnitude of invasion impacts that exist, however, the effect of most non-native species and the full scope of impacts from invasions remains poorly understood. To address this gap, we use a variety of approaches to characterize and test the ecological, evolutionary, and social effects of non-native species across diverse ecosystems.  This work advances understanding of how the Earth’s ecosystems function and also serve to inform resource management and conservation strategies.

Our Projects

Biological invasions provide opportunities to examine how species and ecosystems respond to new arrivals, and how species adapt to new environmental conditions. These types of “natural experiments” provide new insights into many biological processes, especially early in the colonization process, that are not possible with native communities.  We examine invasion ecology at the population, community, and ecosystem level across a diverse range of habitats and organisms, both to advance basic science and inform management and conservation strategies.

Our Projects

Managing biological invasions is a worldwide endeavor that aims to (a) prevent the human-caused spread of species, (b) control and remove unwanted species, and (c) reduce negative impacts to society and the environment. We are evaluating the efficacy and consequences of invasion management strategies and policies in coastal estuaries and marine systems.  Our work is often done in collaboration with local, state, federal and international partners and used actively to inform current management and policy decisions.

Our Projects

We study the dynamic interactions between society, trade, transport, and species in a variety of ways. These include modeling transport networks and biotic exchange, evaluating business model forecasts and their effects on trade routes and species distributions, and assessments of organism transfers across major corridors between oceans and continents.

Our Projects

Understanding how modes of human transportation affect the environment, and biological invasions in particular, is complicated and involves many components including both human and natural history. Human history because most invasions result from human-aided species transfers and invasion patterns often reflect human movements and transportation systems. Natural history because species identifications and their life history characteristics are paramount to knowing which species are non-native and how they have likely been introduced. We work to address these complexities and strive to understand the dynamics of species transport in marine systems. 

Our Projects

Balanced predation and competition are key to the health of any ecosystem. We are examining predation and competition rates in several environments including in the Rhode River near SERC where we study native species in nearshore environments and in introduced fouling communities on the Atlantic and Pacific coasts.  

Our Projects

Communities are constantly being shaped by human activities, activates that can affect hydrology, climate, chemical inputs, species richness (number of species that make up the community), as well as habitat quantity and quality. Our research focuses on how biological invasions change the marine and estuarine communities they invade and how recipient communities protect themselves from invasion. The following highlights a few of our recent projects exploring community changes resulting from nonnative species introductions.

Our Projects

Laravel tunicates

Propagule Pressure in Marine Habitats

We are examining the complex, dynamic interactions between parasites and their hosts, including both the evolutionary and ecological mechanisms that influence these interactions. Our research includes a wide variety of hosts (e.g., seagrasses, bivalves, crustaceans) and parasites (e.g., protists, bacteria, crustaceans).