Research projects

My research focuses on sessile benthic invertebrates - animals like anemones, sponges, bryozoans, and tunicates - in order to understand how larvae disperse and communities assemble on the seafloor. Sessile animals are excellent models for studying dispersal because they live attached to a surface and stay in one place throughout their adult life - the larval stage is their only opportunity to spread to different environments. Larval dispersal and post-settlement mortality have a huge influence on population connectivity for sessile species. Moreover, sessile organisms are exposed to environmental conditions that they cannot escape, so they serve as excellent models for understanding how environmental change influences communities. My lab studies these questions in three systems, described below.

Shipwrecks as biological and cultural resources
Anemones and sponges on the paddle wheel of the Portland.
Photographed using ROV Pixel.

Shipwrecks are by definition not supposed to exist, so any organism that colonizes a shipwreck may have arrived there by mistake. Most shipwrecks are isolated and island-like, separated from natural hard-bottom habitats by expanses of sand or mud, but they are nearly universally inhabited by species that are thought to have short pelagic larval durations and would be expected to settle close to their parents. This presents a paradox: how and why did larvae disperse far away to a habitat that is not supposed to be there? 

My lab uses shipwrecks and other underwater cultural heritage (UCH) as models to understand the colonization and connectivity of island-like habitats. In 2019-2020, I led an interdisciplinary investigation of shipwrecks in Stellwagen Bank National Marine Sanctuary (SBNMS). We used remotely operated vehicles (ROVs) to record high-resolution video and still imagery from shipwrecks in SBNMS, including the iconic steamship Portland, coal schooners Frank A. Palmer and Louise B. Crary, and an unidentified coal schooner. This project had a strong education component, with telepresence broadcasts conducted each year. Recordings are available online, and you can find out more here. We have an upcoming project on shipwrecks in the Gulf of Mexico in summer 2022.
Corals (Porites lobata) on a shipwreck in Palau

We (myself and Dr. Calvin Mires) have also worked to fuse ecological and archaeological concepts into a unified framework for studying the processes that shape underwater cultural heritage over time. We call this framework Maritime Heritage Ecology. Biologists and archaeologists have a lot to learn from each other, and genuine collaboration between these two fields has the power to answer burning interdisciplinary questions to inform effective management of our cultural and ecological resources. 

Recruitment and post-settlement mortality on coral reefs

As global temperatures rise, coral reefs are affected by more frequent and intense bleaching events. However, in some places, corals are genetically adapted to withstand and even thrive in high temperatures. These "refuge reefs" present a number of questions: how do corals survive in stressful environments, are there any trade-offs to thermal tolerance or dispersal away from your home reef, and could heat-tolerant coral larvae repopulate other reefs? 
A coral community at one of our study sites in Palau. 
Photo by Kharis Schrage.

To answer these questions, my lab is collaborating with the Davies lab at Boston University. We are using Palau's Rock Island Southern Lagoon as a model system to disentangle the mechanisms of adaptation and acclimatization that help corals survive in extreme temperatures. This research has implications for future coral restoration projects, because it should show whether thermally-tolerant corals from lagoons could be used to seed outer reefs to help them recover following bleaching disturbance. 

Our research in Palau focuses on the post-settlement stage - right after coral larvae metamorphose and settle on the seafloor - because it is a critical bottleneck in life-histories. We collected samples in 2018 and 2021 and launched a number of experiments using coral juveniles in April-May 2022. We will be returning to Palau several times over the next few years. 

Larval dispersal and recruitment in the Arctic

I have studied benthic communities in the European Arctic since 2011. Svalbard and the Fram Strait are influenced by both Atlantic and Arctic water masses, providing a wide range of environmental conditions in a small geographic area. Working in this natural laboratory provides the opportunity to substitute space for time and understand the dynamics of seafloor communities in a warming Arctic. My lab has shown that the species composition of larvae in the water column and adults on the seafloor are both significantly different between Atlantic- and Arctic-influenced areas, and larval community composition is influenced by oceanographic events. As temperatures continue to rise, larvae of sub-Arctic species will be brought to the Arctic via northward-flowing Atlantic currents. 

Sponges on a stone at 1800 m depth in the Fram Strait.
Photographed using ROV Phoca.
In collaboration with my German colleagues at the Alfred Wegener Institute, I found that the island-like hard-bottom communities on the continental slope west of Svalbard (2500 m deep) take decades to develop. Recruitment is extremely low, so that made me wonder why. Are adults not reproducing? Are the larvae being eaten or carried away by currents? Are newly-settled juveniles dying before the end of the experiment? Answering these questions first requires a basic understanding of reproduction and larval development, which is currently lacking for most Arctic deep-sea species. My lab is presently conducting baseline research on larvae in the deep Fram Strait, in order to figure out how and when common species reproduce and where their larvae go. This research is conducted in the context of the HAUSGARTEN Long-Term Ecological Research observatory during cruises aboard R/V Polarstern. We collected larval samples during expedition PS126 in 2021 and should be going back to sea in 2023.

Check the blog for real-time updates on research in the Meyer-Kaiser lab!