First Work Blog Post!
Note: You can see the complete version of this work post on our work blog, Field Notes, at the following URL (complete with pictures and all!).
The sound coming from the computer was haunting—mystical, pre-historic. It is the type of sound that makes you stop in your tracks, evoking a deep uncomfortable sensation in your gut. Surely, this is what Brontosauruses used to sound like? But wait, are we actually listening to whales sing?
On Saturday, June 19, 2010, I had the opportunity to attend Dr. Sean Todd’s lecture on whale ecology, entitled “The Very Wet and Fat Whales of the Gulf of Maine” at Acadia National Park’s “Interpwoods”, a seasonal training lecture series for us newbies. There were talks on everything from Acadian geological patterns to invasive insects—something for the inner scientist in all of us. When I saw the title of Dr. Todd’s lecture on the schedule, I must admit that my inner little kid immediately vetoed any other plans that I had for that session.
Whales have captured the minds and hearts of people as early as the first stories of the Bible (think the story of Jonah). Beautiful, mystical, and fascinating, it is easy to see why these charming creatures are such prevalent symbols in our society (think “Save the Whales” campaigns). In fact, Dr. Todd uses these social connections with whales to evoke public interest and, in turn, scientific interest that fuels his research. Using audio technology, Dr. Todd studies the migratory patterns of whales as a way to elicit appropriate conservation strategies.
But before I get ahead of myself, what exactly makes the Gulf of Maine so favorable for whales? After all, it takes a lot of energy to sustain a whale population. Think about it in terms of trophic levels: predators (like whales) are never 100% efficient in their use of captured prey energy. Actually, just 1 kg of tuna requires 10 times as many kilograms of mackerel (tuna prey on mackerel). The rest of the energy is lost due to processes like defecation, locomotion, etc. Therefore, in order to make 1 kg of tuna, there must be 10 kg of mackerel for the tuna to eat, 100 kg of herring for the mackerel to eat, 1000 kg of zooplankton for the herring to eat, and 10,000 kg of phytoplankton for the zooplankton to eat (see Figure 1 for a graphical representation). And that’s just to produce one tiny kilogram of tuna. Whew—where in the world is that much productivity present? You guessed it—in the Gulf of Maine!
The proximity of the Arctic creates an ideal environment for highly productive systems: the Gulf Stream brings warm water currents up the coast, while the Labrador Current brings cold, dense, nutrient rich water from the Arctic. And when the warm and cold water mixes, fog is released. The fog, along with nutrient-rich upwellings, create ideal conditions for productive environments.
Upwellings in the Atlantic Ocean bring nutrient-rich waters to the surface (S. Delheimer).
Furthermore, the morphology of the Gulf of Maine allows it to function like an enclosed sea. Ridge walls surround the water within the Gulf and have few openings, limiting the opportunity for organisms to leave the Gulf. The varied morphology of ocean floor within the enclosed Gulf of Maine also contributes to the productivity of the region by creating movement and mixing between deep and shallow waters that encourages the movement of photosynthesized material.
After an overview of the whale phylogenetic tree (did you know that dolphins are considered whales?), Dr. Todd went into further detail concerning his acoustic work with whales. Whales are very vocal animals, and even use vocalizations in courtship, such as in the famous Humpback Whale’s song. Dr. Todd and his research team use hydrophones (connected to buoys) to record underwater whale songs. With this equipment, the researchers can continuously record all sounds passing by that particular buoy 24/7. If you put out more than one buoy, then you can track the whales as they pass by, measuring the exact migratory patterns by comparing the frequencies of whale songs amongst buoys. And while whales do not have distinct, individual songs, they do have distinct accents based on their families, therefore allowing scientists to distinguish among whales by species and individual families.
Using these migratory patterns, scientists can examine migratory trends and use them to determine whether patterns are changing and why patterns are changing. Once the “why” factor is determined, resource management strategies can be developed to encourage the sustainability of whale populations.
For example, with the overfishing of herring (a keystone species), whale sightings drastically declined; whales were leaving the Gulf of Maine to find food in other locations. In simpler terms: humans were competing with whales for herring. Once this pattern was identified, resource management strategies were established to curb the overfishing of herring in order to encourage sustainable whale populations in the Gulf of Maine.
Humpback Whale (S. Delheimer).
And while this entire lecture had the overall resounding “Save the Whales” tone, Dr. Todd made it very clear that his intention is not to emphasize the ecological importance of the whales in particular, rather the ecological importance of trophic systems in general. How will the whales survive if there is no zooplankton to sustain the many trophic levels above it?
Arguably less charismatic than whales, copepods (a type of zooplankton) have inspired less interest and research than whales, yet as a critical trophic system link, they hold considerable ecological importance. Therefore, I propose another campaign: “Save the Zooplankton”. Who is with me? Who knows—maybe the copepods sing a song that we haven’t even detected yet…
acadian rhapsody 