simpple025: Seagrass

Showing posts with label Seagrass. Show all posts

Wednesday, February 6, 2013

From Swimming with Seagrasses to Statistics

vivien February 06, 2013 0

Somewhere down the road ecology evolved from this:

To something like this:

As a member of the Seagrass Ecosystem Research lab here at Florida International University I am, by default, a researcher in two long-term monitoring projects. The first is the FCE-LTER seagrass monitoring project and the other is a seagrass monitoring project in the Florida Keys National Marine Sanctuary. Both datasets have resulted in mounds and mounds of data throughout the years. As a side project to my dissertation I arrogantly decided to conquer said data mounds and turn out some ground-breaking revelations about benthic community structure in South Florida. There's just one problem: I am buried in MOUNDS of data! To analyze these data, it turned out, would be much more complicated than just getting the R code (R is a stats program that hates me, but it's free so I put up with the abuse!) correct so the program will tell me what I want to know. Here is the first figure I generated from this dataset:

Figure 1: R-plot, or as my friend Rob put it, "It looks like a unicorn threw up on your computer." Thanks Rob!

Somehow, R did not tell me what I wanted to know, nor did it write up a nice paper for me to publish. My purpose in generating the first plot was to see if there was any relationships in community structure (species densities) at different regions of the FKNMS (denoted by the 8 different symbols) over time (different colored symbols). The answer was simple: No. While pretty, this figure shows me that there isn't much of a difference among years or across regions for this set of years (I have data for every year beginning in 1996). Where are my ground-breaking results?!

This lack of a relationship is good for the seagrass and macroalgae. However, it has forced me to use my brain in ways in which I was not accustomed. It has spurred me in a different direction with this dataset, though....AND, it's exciting! I'm still in the exploratory stages of the analysis but I'm finding some interesting results. Herein lies the beauty of both long-term datasets and statistics. I am, by no means, a stats whiz - I really struggle with the topic sometimes and throughout my master's degree I threatened the life of my computer, R, and all South Texas seagrasses at one point or another. Though I haven't found anything ground-breaking yet, the sheer amount of data I have at my fingertips allows me to investigate new hypotheses. The benefits are two-fold: 1) I will never be the person who can read a stats book and apply the analysis years down the road. I need the practice - like riding a bike - and with this dataset I get that much needed practice. 2) I get to train my brain to think outside the box and be creative...with MATH! That I enjoy the mathematical brain massage has shocked me.

Friday, September 21, 2012

Epiphanies in Ecology

vivien September 21, 2012 0

For Long-Term Ecological Research (LTER) research in the Seagrass Ecosystems Lab, we venture out into Florida Bay every two months to do a survey of the submerged aquatic vegetation (seagrasses and macroalgae). As I mentioned in my last post (Florida Bay: Beneath the Surface) Florida Bay is a honeycomb of basins, which creates different habitat types. These different habitats, specifically the type and density of vegetation on the floor and sediment type (and many other factors that are beyond the scope of this post), attribute to the color of the water. In a single LTER trip, we see water ranging from deep blue to teal, green, and even brown! After 2 years of running the LTER project for our lab, I am still amazed by the dynamic nature of Florida Bay on the surface and below.

Darker blue waters as we travel to Sprigger Bank.

At Sprigger Bank: notice the greenish patch to the left. There is sparse shoal grass (Halodule wrightii) in that patch. The darker areas have turtle grass (Thalassia testudinum) and manatee grass (Syringodium filiforme).

Milky teal waters of Duck Key.

Duck Key on a different day.

Little Madiera a week after TS Isaac passed through. Little Madiera is located near mainland Florida and receives a lot of freshwater input, especially after a major storm like Isaac.

During my first year as a PhD student, these LTER trips were pivotal in maintaining my sanity and reminding me of the reasons I became an ecologist. As I have developed as a scientist, these trips have become more of a gateway for the development of research questions to test different theoretical concepts that we have studied in depth in our classes. I’m a very visual person and being outside helps me to connect the dots between theory and the development of research questions. I guess you could say, nature is my muse (sorry for the cliché but I really couldn't resist!). For the most part, major discoveries in science have been made rather serendipitously. I have come up with many research questions while being on the LTER and, needless to say, I am not the only scientist who does this. See a great example of what may have started as an ecological epiphany in Science Magazine. I can only hope that when I grow up my epiphanies will be published in such high-impact journals as Science or Nature! Until then...

Tags # Florida Bay # Grad Student Life # Jenn Sweatman Continue Reading

Monday, August 6, 2012

Florida Bay: Beneath the Surface

vivien August 06, 2012 0

Florida Bay consists of mud banks so intertwined it takes an experienced boater (or a great GPS chart tracker, if you’re me) to successfully navigate across the bay. Because flow is somewhat restricted by these mud banks, the basins have developed into unique habitats making each dive of the FCE-LTER seagrass sampling project quite different. At each of the LTER sites within Florida Bay, we estimate percent cover of all seagrass species and many calcareous green algal species, as well as red, brown, and other green algae. We monitor water quality over time via nutrient analyses in seagrass and calcareous green algal tissue, and we collect data on salinity, temperature, light penetration, and water turbidity. Data are located at www.fiu.edu/~seagrass.

Sprigger Bank is our monitoring site located at the western border of the bay where salinity is more stable than that of eastern regions. Sprigger Bank is characterized by dense turtle grass (Thalassia testudinum) and manatee grass (Syringodium filiforme); abundant calcareous green algae (Halimeda sp., Penicillus sp., and Udotea sp.); diverse red and brown algae (e.g., Laurencia sp. and Dictyota sp., respectively); and, brightly colored sponges. Mangrove snapper, grazing shrimp, amphipods and isopods, and megafauna such as sharks and a resident Loggerhead turtle (affectionately named “Spriggy”) inhabit this diverse habitat.

Sprigger Bank seagrass and algae (on a clear day).

Mangrove snappers cruising around Sprigger Bank.

Alex and Chris diving Sprigger Bank. The tide was really low, but it is easier to dive than snorkel these shallow sites because we don't have to worry about dunking our snorkels!

Bob Allen Key is located in central Florida Bay, is deeper than Sprigger Bank, and has fewer submerged plants. Turtle grass is the only seagrass at Bob Allen Key, and the seagrasses are smaller than those at Sprigger Bank. Duck Key is located in eastern Florida Bay. Bob Allen and Duck Key are very similar in depth (about 6 feet) and submerged plants. Compare these two sites in the photos below.

Bob Allen Key

Duck Key

Seagrass beds are important nursery habitats because they provide a safe place for juvenile fish, crabs, and shrimp to live until they become adults. Some animals live in seagrass beds their entire life, and others will use the seagrasses while they are young and migrate to other habitats (such as coral reefs) when they are older. Seagrasses also help clear up the water by trapping suspended sediments and excess nutrients. See below some animals that call seagrasses home!