I am going to talk today about my research on the copepod community in the water offshore of Maine and New Hampshire. There is still a lot we don’t know about coastal zooplankton communities, even though the Gulf of Maine is one of the most heavily studied planktonic communities in the world.  What really drew me to this research was the idea of thoroughly sampling a semi-unknown community and seeing what patterns emerged.  In order to accurately describe any community, you need to know how variable it is through space and time.  Imagine a study of birds of new hampshire.  Over two weeks, people go out and record every bird they see.  If those two weeks are in january, it would be quite inaccurate to assume that the results of this study represent the year-round bird assemblage. 

When it’s not working: Pathetically Crappy Results, Personal Contamination of Reagents

Here are three pairs of species in the same genera, plotted again with months on the x axis and density per cubic meter on the y axis.  Note, though, that each chart now shows both depths, with the light color representing water above the pycnocline, and the dark color representing water below it.  Note also that the scales are not standardized.  These graphs show some very interesting results.
The two species of Centropages show incredibly sharp temporal differentiation, with hamatus declining just as typicus appears in the water column.  Contrast this with Acartia, in which both species have peak abundances in the same month.  However, look at the vertical distributions of Acartia: longeremis is much more prevalent in the sub-pycnocline waters, while hudsonica shows slightly higher numbers above the thermocline. Lastly, both species of pseudocalanus show the same pattern: newmani is much more abundant in surface waters, while moultoni is almost absent from surface waters until the fall.  These species show strong affinities for certain depths, which in turn has large consequences in how they are differentially transported by currents in the gulf of maine. Now I want to broaden our view again, and re-address the entire community.  The graphs I showed before are nice for picking out the dominant species, but it is difficult to perceive how the community is changing as a whole.  For this purpose, I am using Multi-Dimensional Scaling, or MDS…

Here are three pairs of species in the same genera, plotted again with months on the x axis and density per cubic meter on the y axis.  Note, though, that each chart now shows both depths, with the light color representing water above the pycnocline, and the dark color representing water below it.  Note also that the scales are not standardized.  These graphs show some very interesting results.
The two species of Centropages show incredibly sharp temporal differentiation, with hamatus declining just as typicus appears in the water column.  Contrast this with Acartia, in which both species have peak abundances in the same month.  However, look at the vertical distributions of Acartia: longeremis is much more prevalent in the sub-pycnocline waters, while hudsonica shows slightly higher numbers above the thermocline. Lastly, both species of pseudocalanus show the same pattern: newmani is much more abundant in surface waters, while moultoni is almost absent from surface waters until the fall.  These species show strong affinities for certain depths, which in turn has large consequences in how they are differentially transported by currents in the gulf of maine. Now I want to broaden our view again, and re-address the entire community.  The graphs I showed before are nice for picking out the dominant species, but it is difficult to perceive how the community is changing as a whole.  For this purpose, I am using Multi-Dimensional Scaling, or MDS…