Hali Rederer

The Life Aquatic in the Lower Keys with Dr. Vagelli and a Merry Band of Fellow Students

Introduction

I am a graduate student at California State University Sacramento studying Biology with a concentration in Ecology, Evolution, and Conservation. I have just advanced to MS thesis candidacy.

My thesis is researching if Pacific herring (Clupea pallasii) prefers eelgrass (Zostera marina) for spawning?  My research takes place in the biodiverse highly productive waters of Tomales Bay in Point Reyes National Seashore. I took this Marine Field Ecology to improve my field skills and learn different approaches to carrying out scientific experiments in aquatic ecosystems.

 The Rutgers Marine Field Ecology course provided my fellow students and myself rich practical “hands on” experiences integrating scientific field methods with experimental design. Dr. Vagelli’s leadership immersed us in relevant ecology theory and knowledge of tropical seagrass, mangrove forest, and coral reef habitats along with their biodiverse communities.  This course was comprehensive and the pace was fast. We spent 8- 10 hours in the water everyday followed by laboratory classes in the evenings. Topics for specific experiments, laboratory sessions, and discussions derived from our individual research questions, interests, and ideas emerging from our explorations and observations while in the field.  My question: Does the Cudjoe Bay seagrass patches and habitats serve as “nurseries” for fish?

Learning Marine Field Ecology by Doing – the Field Front and Center:

Evolution and the influence of biogeography revealed itself through finding: Pleistocene fossilized coral in limestone, evolutionarily long lived species in Cudjoe basin such as the Horseshoe crab (Limulus polyphemus), and the difference in distribution patterns of sponges, soft corals, and seagrasses in the benthic ecotones of the Atlantic and Gulf oceans surrounding the Keys. Darwin and Wallace came to life for me while carrying out field ecology in the Keys. I used observations to relate ecology, geology, and geography with the biology of resident species while keeping in mind oceanographic processes.

This comprehensive approach makes sense.

Location is important in marine ecology. Scuba diving Looe Reef Marine Sanctuary, which is further out to sea and protected from anthropomorphic influences, provided me with perspective on the importance of context in understanding coastal ecosystems nearshore. Nearshore succession processes are embodied by Mangrove habitat ecology and the lower energy of the waves. Higher temperatures in more protected bays causes silt and small invertebrates to stick to the seagrass leaves, leaf litter build-up, and a chance for different substrates to settle such as mud and sand. Overtime, island building processes give rise to different adaptations of species living at the coastline. The open ocean with rocky reef terrain and higher energy turbulent environments provide different opportunities and challenges for adaptation. It seems there was a significant difference in the variety and size of fish species seen nearshore compared to what we saw on the reef. Examples of this include physical differences in shore versus reef parrot fish and barracudas. On the reef, I saw a variety of soft corals not seen nearshore and found that I was particularly taken in by the beauty of the small intricate feather corals. Dr. Vagelli and the class observed nearshore soft corals covered with algae brown and white. A closer look under the dissection microscope showed red worm or leech like invasive species embedded in the algae attached to some corals sampled. We discussed higher ocean temperatures along with sewage discharge and runoff from agriculture in the Lower Keys as problematic for corals. The question posed was if the source of the invasive species from the ocean carried by waves or from the shore upland?

The Experiments:

Throughout the class we conducted field experiments with methods described in the literature provided by Dr. Vagelli. We used point and line transects creating geographical units of scientific measurement for underwater “mapping” of abundance, richness, and overall biodiversity. We tracked the species we found, their numbers and where we found them along transects. We learned how to tag lobster and sponges as part of a three year running Cudjoe Bay lobster experiment. This experiment tests if lobsters strongly return to the same barrow sponge or group of sponges after being disturbed or re-located. We observed how they use and distribute themselves among sponges and their loyalty to any given sponge as their “home”. The way they grow and molt necessitates that they move around since they outgrow their sponge “home” periodically.  We tagged a lobster living in an abiotic concrete block that actually returned to the concrete block after being displaced. Another experiment is being conducted by Denise, a graduate student and assistant for this course. She is looking at Polychaetous annelid distribution, ecology, and their role in shaping the Keys substrate. How fish use the seagrass community (their connection to seagrass and possible co-evolution with it) is interesting to me. To begin to look at this question we caught juvenile snapper, angle and parrot fish in seagrass meadows of Cudjoe Bay and conducted a stomach content analysis. Bioluminescence in Cudjoe Bays mangrove and seagrass communities were explored on night sureys to look at how widespread it is as a survival strategy and which species exhibits it. Throughout the course we encountered a wide diversity of reef fish species and invertebrates such as: sea cucumbers, sea urchins, sea hares, nurse sharks, sting rays, bat fish, pipe fish, and squid. Lots of questions and ideas for experiments were generated by the class and Dr. Vagelli.

My Life Aquatic as a Scientist in Training:

Throughout this course I had to trust my powers of observation. I had to become a better observer of nature fully engaging my senses so to not miss animals, plants, physical patterns or clues in my quest to understand the connectivity between the various habitats (mangroves, seagrass, reefs, and corals), and their biological communities. The soft bottom habitats and mud flats provided different challenges to scientific observation and measuring activity because living organisms tend to dig in and bury themselves in these substrates. Small occasional bubbles in the mud or holes in the sand are clues that something is present. Camouflage is a survival strategy among marine animals. So it is easy to swim by an important organism and not count that it is present. I learned enormous respect for the work ethic it takes to do very thorough work as a field marine biologist. The time, organization, creativity, and care it takes to carry out thoughtful experiments in the water is challenging and requires perseverance. The rewards of this work are immeasurable. The encounters with marine life and sense of discovery I have when doing marine field work fills me with joy. There is nowhere else I would rather be then under the sea as a scientist.

Finally, this class reminded me how social and team work oriented science can be. Field biology seems to work well when there is collaboration and sharing of ideas. I found it comforting when I observed something that I thought was different and my fellow students or Dr. Vagelli concurred. I also learned that I want to use the scientific names of marine species and review their taxonomy and classifications. Cheers to my fellow students and a heartfelt thanks to Professor Vagelli. I am eager to apply what I learned to my thesis project and I hope to return to the Keys with this class next year.