Geht man auf eine Wanderung in den Bergen, so schaut man sich meistens als ersten Schritt eine Karte an. Genauso ist es auch auf dem Ozean wichtig eine Karte zu haben. Nicht nur eine Karte, in der die Küsten und Inseln verzeichnet sind, sondern vor allem eine detaillierte Karte der Topografie des Meeresbodens. Während Mitte des 19. Jahrhunderts bis Anfang des 20. Jahrhunderts Tiefenmessung noch mit einem Gewicht am Ende eines langen Seils durchgeführt wurde, wird heute in den meisten Fällen das vom Kieler Dr. Alexander Behm 1913 patentierte Echolot genutzt.
Die beste und auch wissenschaftlich anerkannte bathymetrische Daten-Zusammenstellung erstellt GEBCO (englisch: General Bathymetric Chart of the Oceans). Der Datensatz basiert auf zusammengetragenen Daten aus Schiffs-Tiefenmessungen und wurde erstmals vor 120 Jahren der Öffentlichkeit vorgestellt. Heutzutage besteht dieser Datensatz weitestgehend aus so genannter prädizierter Bathymetrie. Das bedeutet, dass Satellitenmessungen gemacht werden, die im Anschluss mit von Schiffen gemessener Bathymetrie verifiziert und ergänzt werden können. Die Satelliten können über verschiedene physikalische Zusammenhänge aus der gemessenen Meeresspiegelhöhe ableiten, ob sich unter Wasser ein Seamount befindet. Dieses Verfahren ermöglicht zwar den gesamten Ozean abzubilden, ist aber sehr ungenau. Seamounts mit einer Größe unter 2 km können zum Beispiel nicht gemessen werden. Der GEBCO Datensatz wird mittlerweile jedes Jahr erneuert. Der einzige Nachteil ist, dass es ihn an detaillierten Metadaten mangelt. Metadaten sind Hintergrundinformationen, die zum Beispiel angeben, von welchem Institut oder auf welchem Schiff die zur Verfügung gestellten Daten gemessen wurden.
Da der Datensatz in großen Teilen auf Schiffsmessungen basiert, ist er stark abhängig von Schiffsrouten, zwischen denen sich teilweise sehr große Lücken befinden. Es sind erst circa 20% des Meeresbodens auf diese Weise vermessen (Mayer et. al 2018). Auf dieser Reise wollen wir einige dieser Lücken kartieren. Genauer gesagt, wollen wir sogenannte Seamounts kartieren.
Seamounts sind unter Wasser liegende Berge meist vulkanischen Ursprungs. Sie sind typischerweise kegelförmig, haben oft Krater, lineare Kämme oder flache Gipfel. Die Form ist häufig abhängig von der Entstehung des Seamounts. Geformt werden sie an Orten, an denen es tektonische Aktivitäten gibt, so zum Beispiel in der Nähe von ozeanischen Rücken, Inselbögen oder an Stellen, wo unter der tektonischen Platte heißes Material aus dem Erdmantel aufsteigt. Seamounts, die in der Nähe von Plattengrenzen entstehen, also dort, wo die Lithosphäre (die Erdkruste und der äußerste Teil des Erdmantels) noch frisch entstanden und dünn ist, sind meistens eher klein. Klein heißt in diesem Fall weniger als 2.5 km Höhe. Größere Seamounts mit 3-10 km Höhe entstehen häufig an Stellen, wo die Lithosphäre schon älter und dicker ist. Obwohl nicht genau bekannt ist, wie viele Seamounts es gibt, ist eines sicher: es sind sehr viele!
Aufgrund ihres vulkanischen Ursprungs sind Seamounts aus geologischer Sicht sehr interessant, da sie einen Einblick in die Zusammensetzung und die Temperatur des Erdmantels geben können. Auch für ozeanographische Betrachtungen sind Seamounts wichtig, da die Bathymetrie Einfluss auf Strömungen und Vermischungsprozesse hat. So können Seamounts als Barrieren fungieren, die verhindern, dass kaltes Tiefenwasser sich mit dem warmen Oberflächenwasser mischen kann. Zu guter Letzt sind sie auch Mittelpunkt eines diversen Ökosystems. Das liegt daran, dass nährstoffreiches Tiefenwasser an ihnen aufsteigt (diesen Prozess nennt man Upwelling) und somit die perfekte Grundlage für Fische und eine vielfältige Flora und Fauna bildet.
Jetzt wissen wir also, warum wir uns für Seamounts interessieren sollten, dass es unglaublich viele von ihnen gibt und, dass viele noch nicht kartiert sind.
Auf unserer geplanten Reiseroute kommen wir an einigen Stellen vorbei, wo Seamounts vermutet werden. Durch nur leichte Kursänderung ist es möglich über einige dieser Seamounts hinweg zu fahren und sie so mit dem Schiffsecholot zu vermessen. Dabei wird ein akustisches Signal zum Meeresboden gesendet, das am Boden reflektiert und dann bei Rückkehr zum Schiff wieder empfangen wird. So kann man durch die gemessene Zeit zwischen Senden und Empfangen den Abstand zwischen Schiff und Meeresboden messen. Dieses Prinzip wird auch hier auf der Maria S. Merian genutzt, mit dem Unterschied, dass nicht nur ein Signal, sondern ein ganzer Fächer von Signalen ausgesendet wird. Damit kann ein Streifen mit einer Breite sechs Mal so groß wie die Wassertiefe vermessen werden. In unserem derzeitigen Messgebiet beträgt die Wassertiefe 2500-3000 m was einem kartierten Streifen von 15 bis 18 km Breite entspricht.
Wir befinden uns im Moment in der Nähe des Mittelozeanischen Rückens, also an einem Ort, wo neue Lithosphäre entsteht. Wie wir bereits gelernt haben, werden die hier zu findenden Seamounts eher kleiner sein. In diesem Gebiet ist auch die Anzahl und Dichte der vorhergesagten Seamounts deutlich größer. Unser erster „überfahrende“ kleine Seamount, noch weit entfernt von dem Mittelozeanischen Rückens, zeigte einen flachen Gipfel mit einer ungefähren Höhe von 450 m. Mit 7.5 km breite sowie 8 km Länge war er fast rund und äußerst sehenswert. In wie weit dieser Seamount in Zukunft weiter erforscht wird, wird sich zeigen.
Auf dieser Fahrt kümmert sich Daniel und Marianne vom „Unterwegs“-Forschungsdaten Projektes der Deutschen Allianz Meeresforschung (DAM) um alles, was mit den Seamounts und dem Fächerecholot zu tun hat. Häufig werden Fächerecholot Daten auch nebenbei erhoben, wenn der Schwerpunkt der Ausfahrt nicht in der Vermessung des Meeresbodens liegt. Im Rahmen des Projekts arbeiteten beide daran, dass diese Daten erhoben und nach der Forschungsfahrt für die Wissenschaft verfügbar gemacht werden. Beide arbeiten für PANGAEA einem Datenrepositorium für Erd- und Umweltdaten.
English version:
If you go on a hike in the mountains, you usually look at a map as the first step. It is also important to have a map being on the ocean. Not only a map listing the coasts and islands, but above all a detailed map of the topography of the seabed. During the middle of the 19th century to the beginning of the 20th century, depth measurement was still carried out with a weight at the end of a long rope, but today the echo sounder patented by Dr. Alexander Behm from Kiel in 1913 is used in most cases.
The most accurate and scientifically recognized bathymetric data collection is produced by GEBCO (General Bathymetric Chart of the Oceans). The dataset is based on collected data from vessel depth measurements and was first presented to the public 120 years ago. Today, this data set consists largely of so-called predicated bathymetry. This means that satellite measurements are made, which can then be verified and supplemented with bathymetry measured by ships. The satellites can derive from the measured sea level via various physical relationships whether a seamount is underwater. This method allows us to map the entire ocean, but it is very inaccurate. Seamounts less than 2 km in size, for example, cannot be measured. The GEBCO dataset is now renewed every year. The only drawback is that it lacks detailed metadata. Metadata are background information indicating, for example, by which institute or on which vessel the data provided were measured.
Since the data set is largely based on ship measurements, it is highly dependent on ship routes, some of which have very large gaps. Only about 20% of the seabed have been measured in this way (Mayer et. al 2018). On this journey we want to map some of these gaps. More specifically, we want to map so-called seamounts.
Seamounts are submerged mountains of volcanic origin. They are typically conical, often with craters, linear ridges or shallow peaks. The shape often depends on the origin of the seamount. They are formed in places where tectonic activity occurs, such as near oceanic ridges, arch islands, or at places where hot material rises from the Earth’s mantle beneath the tectonic plate. Seamounts that form near plate boundaries, i. e. where the lithosphere (the Earth’s crust and the outer part of the Earth’s mantle) is still fresh and thin, tend to be rather small. Small in this case means less than 2. 5 km altitude. Larger seamounts with a height of 3-10 km often form in places where the lithosphere is older and thicker. Although it is not known exactly how many seamounts there are, one thing is certain: there are many!
Due to their volcanic origin, seamounts are very interesting from a geological point of view, as they can provide insight into the composition and temperature of the Earth’s mantle. Seamounts are also important for oceanographic observations, as bathymetry influences currents and mixing processes. Seamounts can act as barriers that prevent cold deep water from mixing with warm surface water. Finally, they are also the centre of a diverse ecosystem. This is because nutrient-rich deep water rises at their flanks (a process called upwelling) and thus forms the perfect basis for fish and a diverse flora and fauna.
So now we know why we should be interested in seamounts, that there are many of them out there, and that a lot of them have not yet been mapped.
On our planned itinerary we pass some places where seamounts are suspected. By only slight course changes it is possible to drive over some of these seamounts and to measure them with the ship echo sounder. An acoustic signal is sent to the seabed, which is reflected on the ground and then received when returning to the ship. Thus, the measured time between sending and receiving can be used to measure the distance between the ship and the seabed. This principle is also used here on the Maria S. Merian, with the difference that not only one signal, but a whole range of signals is emitted. This allows a strip with a width of six times as large as the water depth to be measured. In our current measuring area the water depth is 2500-3000 m which corresponds to a mapped strip of 15 to 18 km wide.
We are at the moment near the Mid-Oceanic Ridge, a place where new lithosphere is forming. As we have already learned, the seamounts to be found here will tend to be smaller. In this area, the number and density of predicted seamounts is also significantly higher. Our first mapped small seamount, still far from the Mid-Oceanic Ridge, showed a shallow peak with an approximate height of 450 m. With 7. 5 km wide and 8 km long, it was almost round and extremely worth seeing.
On this trip, Daniel and Marianne from the “Underway” research data project of the German Marine Research Alliance (DAM) will take care of everything that has to do with the seamounts and the Multibeam Echo Sounder. Frequently, Multibeam data is collected even if the focus of the research is not in the measurement of the seabed. As part of the project, Daniel and Marianne worked to collect these data and make them available to scientists after the research trip. Both are part of PANGAEA, a data repository for earth and environmental data.
Quellen/Sources:
- Gevorgian, J., Sandwell, D. T., Yu, Y., Kim, S.-S., & Wessel, P. (2023). Global distribution and morphology of small seamounts. Earth and Space Science, 10, e2022EA002331. https://doi.org/10.1029/2022EA002331
- Mayer, L.; Jakobsson, M.; Allen, G.; Dorschel, B.; Falconer, R.; Ferrini, V.; Lamarche, G.; Snaith, H.; Weatherall, P. The Nippon Foundation—GEBCO Seabed 2030 Project: The Quest to See the World’s Oceans Completely Mapped by 2030. Geosciences 2018, 8, 63. https://doi.org/10.3390/geosciences8020063
- Damaske, D. (2013): Bathymetry and short term changes of submarine seafloor structures in the area of the former Larsen ice shelf, north west Weddel Sea, Master thesis, http://hdl.handle.net/10013/epic.67a7bbd6-5ada-4764-a961-519e334d5c56
- https://oceanexplorer.noaa.gov/facts/seamounts.html
What do you think about when you hear the words “microplastic pollution?” Your mind may immediately go to imagery of colorful fragmented plastics broken off from bottles, buckets and other items we use in our everyday lives. Or, perhaps, you imagine a pile of microplastic fibers—the tiny, squiggly, spaghetti-shaped plastics that shed from our synthetic clothing. You may be surprised to hear there is another major source of microplastic pollution that’s hiding in plain sight, quite literally under our feet, that might change how you think about microplastics: tire particles.
We all know tires wear down over time—that’s why we have to replace them on our cars roughly every 60,000 miles or so. Every time a vehicle accelerates, brakes or simply drives down the road, the friction between its tires and the pavement creates tiny fragments of rubber, known as tire wear particles.
Driving a car or even riding in a bus is a bit like dragging an eraser across the planet, except the crumbs are microplastics. Toxic microplastics.
Tires are made from a complex mix of natural and synthetic rubber along with a range of additives, fillers and chemical compounds—some of which, like the preservative 6PPD, have been shown to be highly toxic to coho salmon when they break down into derivative product 6PPD-Q in the environment—even in tiny concentrations.
Some studies have shown that a single vehicle’s tires can emit more than two trillion particles per mile driven—and that the average person generates nearly two pounds of tire particles per year! Once these particles are shed from tires, they don’t just disappear. Some are small and light enough to become airborne, drifting away from roadways as dust. Others settle on road surfaces, where they accumulate until the next heavy rain washes them into storm drains and from there, into streams, rivers and eventually the ocean.
That’s why tire wear particles are now considered one of the top sources of microplastics to the environment. In fact, until recent developments in analytical methods, scientists weren’t reliably able to detect tire wear particles in microplastic counts—thus, these pesky microplastics may have been evading our detection for years.
Why green infrastructure may be one of our best near-term solutions
Unlike some sources of plastic pollution, we can’t simply stop driving overnight. Reformulating tire rubber to be less toxic or shed less material, while promising, will take time to develop, test and scale across the global vehicle fleet. So, what can we do about tire wear particle pollution right now?
This is where green infrastructure comes in. Green infrastructure refers to engineered natural systems (things like bioswales, rain gardens, roadside buffers and permeable pavement) that are designed to slow down, filter and treat stormwater before it reaches rivers, lakes and coastlines. Instead of routing runoff directly into storm drains and out to sea, green infrastructure gives contaminated water a chance to percolate through soil, plants and other natural filtration media, which helps trap microplastics, including tire wear particles, preventing them moving further downstream.
Early research on green infrastructure has been promising, showing that these systems are quite effective at capturing microplastics and other contaminants carried in road runoff. But there’s a critical piece we still don’t fully understand: What would it take to scale up green infrastructure across an entire city, and how much of a dent would that actually make in long-term tire wear particle pollution?
Our research on green infrastructure capture of tire wear particles
Funded by the Tire Industry Project, our plastics science and policy teams at Ocean Conservancy have partnered with the University of Toronto on a new study evaluating the costs and benefits of scaling up green infrastructure at the city level specifically to capture tire wear particles.
If you happen to be driving on the roadways of Portland, Oregon, you may spot our scientists crouched over, precariously scooping dirt with spoons from a sample area on the roadside. Don’t be alarmed—that’s just us doing science! Feel free to give us a wave.
Ocean Conservancy is currently working to:
- Quantify the scale of pollution: Collect road dust samples from 30 cities globally to measure both total microplastic and tire wear particle concentrations and determine how different variables (population density, road size, rainfall) might influence those values.
- Assess feasibility: Determine what it would take realistically—logistically, financially and spatially—to scale up green infrastructure across an entire city.
- Model positive impacts: Estimate how much city-scale green infrastructure could reduce tire wear particle pollution entering aquatic ecosystems.
- Compare across cities: Understand how well these solutions might translate across different urban contexts, focusing on Portland, Oregon; Toronto, Canada; and London, England as case-study cities.
- Make our findings accessible: Produce a public-facing toolkit to help city planners, engineers and advocates guide real-world implementation of infrastructure that captures tire-wire particles.
By pairing rigorous science with practical guidance, we hope to help cities move from asking “Could this work?” to confidently building solutions that we know can be effective.
Give today and make a difference!
How can I help?
Tire wear particle pollution can feel like an overwhelming problem. After all, it’s tied to transportation, which most of us rely on every day. But that’s exactly why research like this matters: It gives us a real, near-term path forward that doesn’t require waiting for the entire global transportation system to change first.
You can help by staying engaged with Ocean Conservancy as we continue to dig into solutions for the plastic pollution crisis—one roadway, one storm drain and one city at a time. Together, we can keep working toward a world and ocean free of plastic pollution, forever and for everyone.
The post What are Tire Wear Particles? appeared first on Ocean Conservancy.
A small jellyfish-like animal recently reported from Vejle Fjord has attracted attention. Clear photographs suggest that it belongs to the genus Gonionemus and may possibly be the clinging jellyfish, Gonionemus vertens (Picture courtesy to Jonas Bøgelund Poulsen)
Unlike the large jellyfish commonly encountered along Danish coasts, Gonionemus vertens is a small hydromedusa, usually only around 1.5–2.5 centimetres across. Its transparent bell reveals four coloured reproductive structures arranged like a cross. Numerous fine tentacles surround the bell, often appearing bent or angled. Small adhesive pads near the ends of the tentacles allow the animal to attach itself to eelgrass, seaweed and other submerged vegetation.
This unusual behaviour explains its English name: the clinging jellyfish. During the day, it often remains attached to vegetation rather than drifting freely with the current. At night, it becomes more active and swims into the water column to feed on zooplankton and small crustaceans. Consequently, it can easily remain unnoticed even in places where it is already established. Another reason the species can be difficult to detect is its life cycle. The visible medusa is only one stage. For much of its life, the animal may persist as a minute polyp attached to a hard surface, shell or vegetation. These inconspicuous polyps can reproduce asexually and later release new medusae when environmental conditions become favourable.
Gonionemus vertens is generally considered native to the northern Pacific but has been introduced into several parts of Europe and the Atlantic. Transport on ship hulls, in ballast water or with movements of oysters and other marine organisms has been suggested as possible pathways, although the pathway responsible for any particular occurrence is rarely known with certainty.
Despite its delicate appearance, the animal should not be touched. Some populations possess powerful stinging cells and have caused intense pain, swelling, muscle cramps and, in rare cases, serious allergic reactions. Sting severity differs considerably among regions, which is one reason researchers suspect that animals currently grouped under the name G. vertens may represent a complex of closely related forms.
The Vejle Fjord observation is therefore scientifically interesting, but it should not yet be presented as a confirmed record of G. vertens. Anyone encountering a similar animal should photograph it without handling it and record the date, exact location, approximate size, number observed and surrounding habitat. Observations can be submitted to Denmark’s national species portal, Arter, where they can be evaluated and contribute to tracking changes in Danish marine biodiversity. Please use either my App: GoJelly JellySpotter or reprot to the Arter.dk: Gonionemus taxon page and Danish species-reporting portal.
References:
Edwards, C. (1977). A study in erratic distribution: The occurrence of the medusa Gonionemus in relation to the distribution of oysters. Advances in Marine Biology, 14, 251–284. DOI: 10.1016/S0065-2881(08)60448-4.
Govindarajan, A. F., Källström, B., Selander, E., Östman, C., & Dahlgren, T. G. (2019). The highly toxic and cryptogenic clinging jellyfish Gonionemus sp. (Hydrozoa, Limnomedusae) on the Swedish west coast. PeerJ, 7, e6883. DOI: 10.7717/peerj.6883.
The JOIDES Resolution (JR) was a renowned, international, scientific research ship. It was home to over 190 expeditions, each sailing for 60 days at a time without docking. Scientists and crew members from all over the world met to discover Earth’s secrets through studying ocean cores. Every two months the JR would get a new crew, sailing to an entirely new place. This once in a lifetime experience forms special and unforgettable social connections.
Since working on the JR I’ve kept those connections strong with snail mail. I have always been an avid penpal, so meeting new friends means new addresses to send my letters and postcards to. Experiences like sailing on the JOIDES Resolution or participating in programs like OCEAN CORE Academy is one of the ways I’ve met people from all over the world.
Now that the JR is retired, there is no more scientific research drilling being done through the International Ocean Discovery Program (IODP). But, there is still plenty to learn from ocean cores, and plenty of people to meet through programs like OCEAN CORE Academy (OCA). OCA is an annual summer opportunity from the U.S. Scientific Support Program (USSSP) that hosts undergraduates interested in geoscience related careers. Students can apply to this program for a chance to research and study data recovered from cores originally brought up by the JR, now located at the Gulf Coast Repository (GCR) in College Station, Texas. Students also practice forms of science communication with the guide of mentors. As a science communicator and fan of snail mail, I ran a craft night teaching students how to make and send science-themed postcards.
Fig. 1) students using watercolor to paint onto 4 by 6 inch board paper, a photo of a thin section slide is in the background. Photo by Dr. Leah Joseph.
For this project, we based the cover image of the postcards off of rock thin section slides. These slides are a slice of a hard rock or mineral that’s been glued to a microscope slide, sanded to 0.03 millimeter thickness, and polished. Thin section slides are used to identify grain size, shape, color, and other physical properties. This helps scientists understand the textural relationships between the rocks and determine the origin or evolution of the parent rock. Thin sections can also be helpful for identifying minerals using cross polarized light (XPL). XPL reduces light reflection and glare, commonly used for sunglasses and professional photography, but in a polarizing microscope, XPL is used to create a dark field causing certain minerals to appear brighter and more visible. Different colors are associated with different minerals, and as the stage of the microscope rotates, light passes through the slide in unique ways aiding scientists with identification. Identifying minerals can help scientists in understanding more about where the rocks came from and how old they are. These thin sections are not only informative, but are incredibly beautiful, making unique and stunning postcard covers.
Fig. 2) Examples of thin section slides under a XPL microscope, bronzitite (left) and gabbro (right). Sourced from here.
After the OCA students finished their paintings, my home-made “post card” stamps go on the back, a stamp gets added, and they’re ready to be mailed out. Although most OCA participants this year were U.S. based, they came from all over, ranging from Staten Island to San Francisco to Arizona to Connecticut. In addition to one mentor from New Zealand! For many of these students this was their first time traveling on their own, and their first time forming long-distance connections. With these scientific postcards, OCA students can stay connected by reminding each other of the science they learned together. My experience on the JR taught me great things about geological research, but it also gave me life long connections that I cherish. Although the JR is gone, its legacy lives on in our memories and the ways we stay connected with friends. I’m grateful to know that even without an international ship, I’m still able to add friends to my address book.
Fig. 3) Examples of participant made postcards
Written by Kellan Moss
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