Zostera marina is a seagrass species, commonly known as eelgrass, that is found on both coasts of the United States, as well as in Europe. Unfortunately, Zostera is disappearing all over the place, including right here in New York. This could have devastating impacts on animals that rely on eelgrass as foraging grounds, or, as is the case with scallops, use it as a refuge from predation. This is its story, as seen through the eyes of an aspiring graduate student...
Obviously, a lot can change in the next day or two, but as it is currently, Long Island is still well within the cone of probability of Hurricane Earl. Now, we get lots of predictions every year that this is our year (Long Island is said to be long overdue for a direct hit from a hurricane), and it is inevitable that a hurricane will hit Long Island in the future. I just didn't think immediate future. I was kind of hoping I'd be long gone. After all, Long Island is hardly built for hurricanes. There is really only 3 roads off the Island (and for places out on the East End, only 1 road). This is in addition to being relatively low lying (many places get flooded with just a little rain) and lots of bodies of water which will rise with storm surges. Hurricanes also can potentially disrupt the local environment and ecology, as the last major hurricane (the 1938 Hurricane, and here, here, and images here) opened up the Shinnecock Inlet and changed the South Shore estuary system.
So I am obviously worried about my research as well. I have experiments running out in the field that aren't done running yet, so I need to keep my fingers crossed that my equipment stays in place. Clearly I am selfish in my concern about the hurricane, but who wouldn't be?
In the next day or two I will post an article on the impacts of hurricanes on the benthos, which is a major concern for me and, in my honest opinion, for Long Island, since most of the native benthos don't experience anything like a hurricane.
In the most recent issue of Marine Biology, there is a manuscript addressing the issue of 2 introduced species and their interactions with one another. Its an interesting read - one of the species is a commercially important bivalve, the Manila clam, which was introduced in the early 20th century and is now one of the most commercially harvested clams on the west coast of the US. The second is Zostera japonica, dwarf eelgrass, an introduced seagrass species which can establish itself on tidal flats. The idea is that this new seagrass species may be of detriment to the now commercially important manila clam. While there is certainly literature which suggests that seagrasses might enhance bivalve growth - see works involving hard clams and eelgrass by Elizabeth Irlandi and Mike Judge - it certainly stands to reason that eelgrass dampens water currents, and likely decreases the amount of food available to suspension feeders, particularly those distant from the edge of the seagrass (where the food availability might be enhanced). And so the team led by Chaochung Tsai aimed to investigate the impacts the invasive eelgrass had on the clams, and whether the clams might enhance the introduced grass. They chose 3 habitats - seagrass present, seagrass removed, and harrowed habitats. The presence of seagrass, while not necessarily impacting shell extension of the infaunal manila clam, did significantly negatively influence clam condition (tissue weight to shell volume ratio). On the flip side of the coin, while bivalves have been shown to influence eelgrass growth through nutrient additions - see the Peterson Lab publications - this apparently is not the case for the manila clams and dwarf eelgrass. In this experiment, clams did not enhance growth nor impact sediment porewater nutrients. In fact, the only positive effect of the introduced seagrass was on itself. Pretty interesting (and before I read it, unexpected) results.
Tsai, C., Yang, S., Trimble, A., & Ruesink, J. (2010). Interactions between two introduced species: Zostera japonica (dwarf eelgrass) facilitates itself and reduces condition of Ruditapes philippinarum (Manila clam) on intertidal flats Marine Biology, 157 (9), 1929-1936 DOI: 10.1007/s00227-010-1462-0
Irlandi, E., & Peterson, C. (1991). Modification of animal habitat by large plants: mechanisms by which seagrasses influence clam growth Oecologia, 87 (3), 307-318 DOI: 10.1007/BF00634584 Judge M, Coen L, Heck KL (1993). Does Mercenaria mercenaria encounter elevated food levels in seagrass beds? Results from a novel technique to collect suspended food resources Marine Ecology Progress Series, 92, 141-150
So I am not sure how this blog roll tag meme quite got started. Chuck over at Ya Like Dags tagged me, and Mike at Cephalove tagged him. The idea is that science bloggers of substance (I am so excited to have substance) tag each other to answer a few questions. Since I have been tagged, here it goes:
1) Sum up my blogging motivation, philosophy and experience in exactly 10 words
2) Tag 10 other bloggers of substance in the hopes they check this blog regularly and thus continue the meme. (By the way, I didn't know what a meme was, I had to look it up. Thats how internet savvy I am).
1) Like to use pictures to tell my stories about scallops.
Those are two characters from a series of books by Suzanne Tate. They are pretty good, and geared toward children. I have read one of her books, Skippy the Scallop, to kindergarten classes the last two years. Its one of those things I try to do from time to time.
But I digress. Crabby and Nabby are blue crabs. And that relates to my research how? Well I decided a logical step in the progression of my research was investigating blue crabs as scallop predators. This isn't new. What is new, however, is that blue crab abundance has exploded on Long Island. Now, NY is certainly within the range, but toward the northern limits of their range. With warming temperatures, the blue crab populations are growing here on Long Island. This can create a problem with the scallop restoration efforts here. Why? Well, blue crabs are voracious bivalve predators, and they recruit to submerged aquatic vegetation, and especially seagrasses like Zostera marina. These are the very same habitats to which scallops recruit. So it is entirely likely that the increase in blue crabs in NY will have a significant impact on bay scallops, based on the available literature. That being said, no one has investigated blue crabs in Long Island. So one step of my research is now investigating where the blue crabs are recruiting in a south shore lagoon estuary, Shinnecock Bay. I have been doing this for the last two weeks, but will continue to monitor 3 times a week through October. At these same sites, I am monitoring bivalve recruitment to see if indeed scallops and blue crabs are recruiting to the same areas. Then I will do some mesocosm predation experiments with varying complexities and investigating the canopy of vegetation as above bottom refuges for scallops from the swimming crabs. All in a days work!
I am a marine biologist that is currently attending graduate school at the School of Marine and Atmospheric Sciences, Marine Sciences Research Center, of Stony Brook University, New York. I am very interested in marine ecology and have been focusing my studies on bay scallop interactions with their habitats. I plan to investigate various anthropogenic impacts on bay scallop populations for my PhD dissertation. This blog will highlight the details of my graduate research, from bay scallop-eelgrass interactions as previously mentioned, to alternative habitats for scallops, such as Codium, to trophic cascades, and more. Enjoy!
Eelgrass is an important habitat for multiple marine species, including the bay scallop
Scallop on Artificial Eelgrass
This tethered juvenile bay scallop attached itself to my artificial eelgrass...
The decline of eelgrass meadows
Eelgrass, Zostera marina, is a flowering, marine vascular plant that remains submerged all the time. This is quite a feat for vascular flowering plants, and only a few dozen species world wide are capable of growing completely submerged in a marine environment. Eelgrass creates and extremely important habitat, its upright structures and complex root system create a 3-D living space for many different types of animals. It is (or was) the dominant habitat forming SAV (submerged aquatic vegetation) throughout much of the coastal waters in the northeastern United States. Unfortunately, for various reasons, eelgrass meadows have seen drastic declines, and in many locations eelgrass only exists in a mosaic of small patches. This is extremely bad news as many of the important, and formerly important, commercial and recreational fisheries of the northeast US are dependent on Zostera at some part of their life cycle as a nursery and foraging ground. Some of the species are finfish like tautog, bluefish, fluke, winter flounder, porgies, while others are shellfish such as blue mussels, hard clams, oysters, bay scallops, and blue crabs. Many of the aforementioned species support or once supported vibrant fisheries. Many of those fisheries have collapsed, also for various reasons. However, is it possible there is a link between the crash of the fisheries, the decline of Zostera and the failure for recovery on both ends?
Eelgrass, Zostera marina, a temperate seagrass species, providing a vital habitat for numerous marine species
Scallops in eelgrass
Some adult bay scallops we planted in eelgrass for a free release survival experiment we conducted
If you live in coastal zones, urge your local and state representatives to push for environmental issues that you are concerned about. Ask for more stringent rules regarding the destruction of existing eelgrass. Encourage restoration programs to be set-up. Call your state and national representatives and ask them what they are doing to protect our precious resources. Practice safer boating and know the undersea terrain - i.e., don't drive your boat in very shallow water. Avoid clamming in eelgrass meadows.