Water and eggs!!

Some bays are finally filling.  Rainbow Bay is still completely dry but some of the bays that tend to hold water for much longer than Rainbow are filling up.  We've started to see and/or hear evidence of breeding for leopard frogs, spring peepers, tiger salamanders, spotted salamanders, and ornate chorus frogs.  At the H02 wetlands we have seen a good number of leopard frog egg masses and as a result we have started our next big ecotox experiment looking at the effects of copper and zinc on leopard frogs.  Set up 234 containers with ~25 eggs each yesterday.  Was a crazy day but the experiment is underway!

The photos are of southern leopard frog egg masses (top photo) and tiger salamander egg masses (middle photo) in Ellenton Bay (bottom photo). Unfortunately the tiger salamander egg masses seem to have been nailed by some very cold weather and don't look very good.  Hopefully there are more females left to enter the bays and breed now that we are having nice nighttime weather (heat is off and windows are open!).

Skunk season

Still not seeing that many amphibians at the fences, but we do have some bays filling and we've opened up part of the drift fence at Ellenton Bay to get some leopard frog pairs for breeding.  Ellenton Bay is a site we use as a reference site to compare to the H-02 Constructed Wetlands and to some coal fly ash studies we do.  Ellenton Bay is now holding water and a decent number of leopard frogs and mole salamanders have gone in.  No egg masses yet but that should come soon. Anyway, we have had some rain and that caused most of the remaining marbled salamanders to leave Rainbow Bay and a bunch more mole salamanders enter the bay.  Unfortunately we also had a predation event.  Sometimes raccoons, possums and/or skunks hone in on the good nights for amphibian to move and they go feast.  The marbled salamanders are distasteful and it looked like something had "sampled" a handful of marbleds and then didn't like what they found and didn't actually eat them.  But they did kill them in the process.  We weren't sure who the culprit was but then we did smell skunk.  Tis the season to see more skunks around as their mating season gets underway.  Today we saw a skunk and I managed to get a few photos with my cell phone.  This one was fairly close to Rainbow Bay and could have been the culprit.  I actually like skunks and even their smell in moderation.  I'd like them even more if they would learn to avoid the distasteful salamanders rather than sampling them again and again. This one has really faint stripes.  We only have two types of skunks in SC: striped skunks, Mephitis mephitis, and spotted skunks, Spilogale putorius.

Constructed wetlands....part 6

The other day we talked about copper as an environmental contaminant.  We have been researching the effects of copper on amphibian development.  As I've said, 13 species have colonized the wetlands.  So far we've done some studies on southern leopard frogs, southern toads, and eastern narrowmouth toads.  We look at how the eggs develop and hatch under different levels of copper and then how well larvae survive to metamorphosis--such as the southern toad on it's way to terrestrial life with back legs out, but still a tail and no front legs yet.  We do this in a lab facility where we can control everything and just vary copper exposure in the water but then also do experiments in the actual constructed wetlands where they are exposed to copper in the water but also through the food they eat.  In the wetland they also have exposure to elevated zinc and elevated pH.  We have a lot of interesting results and are working to write up some papers, but one of the most important things we've seen is that each species responds very differently to copper with leopard frogs being the most tolerant and the eastern narrowmouth toads the most sensitive.  Really emphasizes how doing an ecotox study on one species isn't good enough for setting regulations.  right now we are setting up a really large study with leopard frogs that will start looking at how the route of exposure (food or water) of copper affects them and how exposure to both copper and zinc interacts.  Crazy time now trying to get it all set up, but will be a fun and hopefully interesting study.

Constructed wetlands....part 5

Eastern narrowmouth toad eggs

Southern toad eggs

The other day I mentioned that the H-02 wetlands were constructed to take help remove copper and zinc from the water leaving an industrial facility before it enters the watershed.  Thought I should discuss the fact that this is not a pollution problem restricted to DOE sites like the Savannah River Site.  Metal contamination is actually a huge problem over a large percentage of the world and copper is a really widespread contaminant.  Like many things, copper and zinc are essential elements and are critical to many of our (and most species') biochemical pathways, but in excess they become toxic.  Copper occurs naturally in the environment but in many places it's concentrations are quite elevated.  Copper is used in the production of many things including kitchen tools, paintings, water pipes, building siding and it's used as a fungicide and algaecide.   As a result it can be really high in water passing through corroding pipes, in all the stormwater runoff from parking lots, roads, and roofs, and from runoff from agricultural areas and mines.  On roads it actually is released from brake abrasion.  In some places it is used very heavily (as copper sulfate) to kill algae in ponds or aquaculture systems or as a pesticide on crops. Unfortunately aquatic environments are always the final receptor of urban wastewater, runoff from mines and agriculture, and industrial effluents--plus some aquatic environments have copper sulfate directly applied to control algae.  It is estimated that 15 million tons of copper are used annually so it's not surprising that many aquatic environments have a lot more copper than would be found there naturally.  As a result, there has been a lot of research on the effect of elevated copper on fish and it can be extremely toxic (and often fatal) to fish.  The EPA has set regulations for how much copper can be allowed in water and in industrial effluent.  The industrial facility on site where the H-02 wetlands exceeded that value and that's the reason the wetlands were constructed---and they do a great job of reducing the copper level to a "natural" level before the water enters Upper Three Runs Creek which runs to the Savannah  River.  Though we know copper is highly toxic to fish there is a lot less known about it's effect on amphibians and that's what we've been studying and will talk about next.  Two of the species we've studied are Southern toads and Eastern narrowmouth toads and their eggs are shown in the photos.