A Shallow Water Ferrous-Hulled Shipwreck Reveals a Distinct Microbial Community

Metallic Shipwrecks and Bacteria: A Love-Hate Relationship

For two centuries, metallic shipwrecks have been relics of the history of navigation, trade, and wars. They are also hotspots of marine biodiversity. The degradation of these shipwrecks not only threatens their environment through the release of polluting compounds, but also the reef ecosystems that have developed. Microorganisms are at the root of both degradation and reef-building, and their roles are still more hypothetical than validated. The aim of this review is to focus on the known or suggested relationships between bacteria and metallic shipwrecks and to identify issues that highlight the need for multidisciplinary studies to better understand the mechanisms at play in these ecosystems with the aim of protecting both the environment and these sites of underwater cultural and natural heritage.

Construction and evolution of artificial reef ecosystems: Response and regulation of marine microorganisms

Artificial reefs (ARs) are an important means of improving marine ecological environments and promoting the sustainable use of marine biological resources. After AR deployment, biological communities undergo dynamic changes as species succession and shifts in community structure. As the most sensitive frontier affected by the environment, the complex and dynamic changes of microbial communities play a crucial role in the health and stability of the ecosystem. This article reviews how AR construction affects the composition and function of marine microorganisms, their contributions to ecosystem stability, and the interaction mechanisms between microbial and macroecological systems. We focus on the responses and regulatory roles of microorganisms in AR ecosystems, including changes in microbial abundance, diversity, and distribution in the environment and on reef surfaces. Additionally, we examine their roles in nutrient cycling, the carbon sequestration, and their interactions with higher trophic organisms. We identify critical knowledge gaps and research deficiencies regarding microbial community risks that need to be addressed, which provide a framework for studying the complex relationships among marine environments, microbial communities and macrobiotic communities in the process of marine ranching construction.

Evaluation of biofilm assembly and microbial diversity on a freshwater, ferrous-hulled shipwreck

Abandoned shipwrecks are sitting at the bottom of oceans, lakes, and rivers around the world. Over time, microbial-comprised biofilms can help protect wrecks against chemical corrosion or contribute to their deterioration through microbiologically influenced corrosion (MIC) by organisms including iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB). Assessing the community assembly of these biofilms will give us a better understanding of the role these microbes play in MIC and the factors that influence it. Here, we determine if microbial community composition differs across a shallow freshwater ferrous-hulled shipwreck environment. Results suggest that there was a statistically significant difference among the sample types indicating the wreck environments around Accomac influenced the community composition. This is consistent with previous observations within an estuarine, shallow-water wreck environment. Bacteroidota, Chloroflexota, and Cyanobacteriota were the primary taxa responsible for differences among these wreck environments. Interestingly, port-side biofilm communities were significantly different than those on the starboard side suggesting physical factors of the environment drove niche partitioning on each side of the wreck. Similarly, FeOB enrichments and known FeOB taxa were found across the entire wreck but were primarily found in samples associated with the port side of the wreck. Amplicon sequencing identified both known FeOB and SRB taxa with a higher proportion of FeOB than SRB. Overall, these results indicate that there is niche partitioning of the microbial communities as well as with corrosion-causing taxa within a shallow freshwater wreck site which may lead to variation in how microbes may contribute to the protection or deterioration of these ferrous-hulled wrecks.

IMPORTANCE

The overall structure, abundance, and diversity of microbial communities on shipwrecks have recently been studied in marine aquatic environments. While previous studies have looked at the microbial communities associated with shallow-water ferrous-hulled wrecks in marine environments, studies focusing on freshwater wreck systems are limited. The purpose of this study was to determine microbial community diversity and composition trends across the Accomac shipwreck environment. Furthermore, shipwrecks are colonized by corrosion-causing taxa, such as iron-oxidizing bacteria and sulfate-reducing bacteria which have been shown to influence the biocorrosion of ferrous-hulled structures. Identification of various microbes in biofilms, as well as corrosion-causing microbes, can help researchers identify the role they play in aquatic ecosystem development and persistence as well as artificial reef integrity. Understanding how microbes assemble on wrecks will provide insight into preservation strategies to prevent deterioration of these wrecks over time, as well as limiting biocorrosion of similar structures.

Shipwreck ecology: Understanding the function and processes from microbes to megafauna

An estimated three million shipwrecks exist worldwide and are recognized as cultural resources and foci of archaeological investigations. Shipwrecks also support ecological resources by providing underwater habitats that can be colonized by diverse organisms ranging from microbes to megafauna. In the present article, we review the emerging ecological subdiscipline of shipwreck ecology, which aims to understand ecological functions and processes that occur on shipwrecks. We synthesize how shipwrecks create habitat for biota across multiple trophic levels and then describe how fundamental ecological functions and processes, including succession, zonation, connectivity, energy flow, disturbance, and habitat degradation, manifest on shipwrecks. We highlight future directions in shipwreck ecology that are ripe for exploration, placing a particular emphasis on how shipwrecks may serve as experimental networks to address long-standing ecological questions.

Microbially influenced corrosion and rust tubercle formation on sheet piles in freshwater systems

The extent of how complex natural microbial communities contribute to metal corrosion is still not fully resolved, especially not for freshwater environments. In order to elucidate the key processes, we investigated rust tubercles forming massively on sheet piles along the river Havel (Germany) applying a complementary set of techniques. In-situ microsensor profiling revealed steep gradients of O2 , redox potential and pH within the tubercle. Micro-computed tomography and scanning electron microscopy showed a multi-layered inner structure with chambers and channels and various organisms embedded in the mineral matrix. Using Mössbauer spectroscopy we identified typical corrosion products including electrically conductive iron (Fe) minerals. Determination of bacterial gene copy numbers and sequencing of 16S rRNA and 18S rRNA amplicons supported a densely populated tubercle matrix with a phylogenetically and metabolically diverse microbial community. Based on our results and previous models of physic(electro)chemical reactions, we propose here a comprehensive concept of tubercle formation highlighting the crucial reactions and microorganisms involved (such as phototrophs, fermenting bacteria, dissimilatory sulphate and Fe(III) reducers) in metal corrosion in freshwaters.

Underwater cultural heritage is integral to marine ecosystems

Underwater cultural heritage (UCH) supports marine biodiversity and influences connectivity. UCH structure, colonizing organisms, and anthropogenic stressors interact to shape sites over time, but these interactions are poorly understood. Here, we express the urgent need for biology-archeology collaborations to address interdisciplinary questions. We also codify the emerging field of Maritime Heritage Ecology.

Structural factors driving benthic invertebrate community structure on historical shipwrecks in a large North Atlantic marine sanctuary

Shipwrecks are irreplaceable historical resources and valuable biological habitats. Understanding the environmental and anthropogenic factors affecting shipwrecks is critical for preservation in situ. We used remotely operated vehicles to study the benthic invertebrate communities on four shipwrecks in Stellwagen Bank National Marine Sanctuary (SBNMS, North Atlantic, USA). Shipwrecks included coal schooners and a passenger steamer, all >100 years old. These large, complex structures hosted dense populations of invertebrates (34 species), especially on high-relief and overhanging substrata. Some species that are otherwise rare in the community may proliferate through asexual reproduction and form dense populations on shipwrecks. We also investigated impacts of entangled fishing gear on the invertebrate communities on each shipwreck and found that areas with the most ghost gear have lower species richness and different community structure. Fishing, particularly bottom trawling, damages shipwrecks and poses a threat to these valuable cultural resources and biological habitats in SBNMS.

Practicing Critical Thinking in Undergraduate Microbiology Classes by Presenting News Stories with Data Evidence

Developing scientific literacy is a key objective in undergraduate biology education. However, finding and accessing important primary research articles and drawing conclusions from original data is often challenging for students. The approach described here aims to alleviate these challenges by using news stories as a starting point for identifying important research findings and having students ultimately explain the findings with original data. The students identify a microbial news story, find and read the original peer-reviewed article the news story was based upon, and finally, present the key findings in class, while explicitly focusing on presenting data evidence, followed by the key conclusions that resulted in the news story. This approach practices scientific literacy and critical thinking and promotes a student-centered learning environment.

Introducing a "core steel microbiome" and community functional analysis associated with microbially influenced corrosion

Microorganisms attached to aquatic steel structures play key roles in nutrient cycling and structural degradation processes. Corrosion-causing microbes are often the focus of studies involving microbially influenced corrosion, yet the roles of remaining community members remain unclear. This study characterizes the composition and functional potential of a 'core steel microbiome' across stainless steel types (304 and 316) and historic shipwreck steel along salinity gradients in North Carolina estuaries. We found higher phylogenetic evenness and diversity on steel surfaces compared to sediment, and at lower salinities. The core steel microbiome was composed of heterotrophic generalist taxa, and community composition was most strongly influenced by salinity. Substrate type was a secondary factor becoming more influential at higher salinities. The core steel microbiome included members of Sphingobacteriia, Cytophagia, Anaerolineaceae, Verrucomicrobiaceae, Chitinophagaceae, and Rheinheimera. While salinity differences led to phylogenetic separations across microbial community assemblages, functional genes were conserved across salinity and steel type. Generalist taxa on steel surfaces likely provide functional stability and biofilm protection for the community with limited functional trade-offs compared to surrounding environments. Further, characterization of a core steel microbiome increases the understanding of these complex steel surface microbial communities and their similarities to core microbiomes in other environments.