Food chains link the creatures of coastal ecology

Don’t stick your hand in that shell! You don’t know who might be home. It could be a carnivorous snail or a “clawsome” crab. Take a look at our Texas state shell, the lightning whelk or left-handed whelk, which feeds on bivalves like oysters and clams. Perhaps the snail that makes the shell is still hiding inside, or perhaps the shell is home to a hermit crab. Unlike most crabs, hermit crabs use the shells of snails as homes to protect their soft bodies.

Hermit Crab

Hermit crab taking residence in an empty lightning whelk shell.

Texas is home to some fascinating creatures, and our coast is no exception. In addition to the Gulf side beaches, there are salt marshes, jetties and the bay to investigate. Our coastal habitats are just waiting to be explored, and with the right gear, you can see organisms at every trophic level. (You knew I was going to talk about food chains, didn’t you?) 

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Lightning whelk snail retracted into its shell, operculum blocking the opening.

Most folks will notice some of the upper-level consumers: birds like pelicans and gulls. Who could miss the gull snatching your unattended hotdogs? Or the pelicans plummeting into the water face first to catch fish? Maybe you’ve noticed fishermen along the beach as they pull in small bonnethead sharks. Some animals may require good timing and tons of mosquito repellent to see, like our rare and critically endangered Kemp’s ridley sea turtle. If you pay attention, there are even rattlesnakes catching mice that are feeding on insects and plants in the dunes!Food Web

As you follow a food pyramid from the apex down to the base, top predators like humans and sharks feed on the organisms in the level below. There you might find the larger bony fish we feed on, like redfish or snapper, and below them you can find some of the crustaceans and mollusks they feed on in turn. Crustaceans, like our blue crabs, stone crabs, and the smaller ghost crabs, often scavenge in addition to feeding on mollusks, worms, or even plant matter. Many of our mollusks are filter feeders, like oysters, pulling algae and plankton from the water. Finally, at the base of the food pyramid, there are the producers. The phytoplankton and algae make their own food with energy from the sun.

A food chain pyramid is a great way to show different types of food chains on one example. I used a pyramid created by my friend Julia and drew examples of food chains from our coast on it. One side has the trophic levels on it and the other three sides have example food chains. What’s on the bottom of the pyramid? The Sun, of course!Pyramid

Coastal ecology isn’t just about sand, shells, and dodging gulls. It’s also about the interactions between plants, animals, and their environment. The plants anchor the dunes, the dunes protect and replenish the beach sand, the sand houses animals like mole crabs and mantis shrimp, and we get to enjoy it when we protect it.

If tracking home beach sand in your shoes, car, towels, and suits doesn’t excite you, our new Hamman Hall of Coastal Ecology may be just the air-conditioned trip to the coast you need on a scorching summer day in Texas. Members, come join us Memorial Day weekend to see wonders of the Texas coastline!

Mala-whaaa? Discover the incredible world of mollusks in the Strake Hall of Malacology

One of the most awesome parts of working for a Museum (especially one as large as ours) is how many people you get to meet and work with – all with something different that gets them excited about science! It’s easy to celebrate your inner geek when you can find fellow geeks who you can geek out with in a geeky fashion while geekily reveling in unique parts of the Museum.

You could ask anyone here and they’d be able to tell you which part of the Museum brings this out in me: the Strake Hall of Malacology.

“Mala-whaaaa?” you may ask.

Malacology is the study of mollusks, an incredible group of creatures that includes octopi, scallops, and my favorite, snails (but more on them later). They’re invertebrates belonging to the phylum Mollusca, and there are over 85,000 species of them in the world!

These invertebrates all have three features in common but are otherwise extremely diverse. They have a mantle containing a cavity used for breathing and excretion; a radula, which is used for feeding; and the same structure to their nervous systems, with two pairs of nerve chords: one serving the internal organs and another for locomotion.

Mollusks are also able to use their internal organs for multiple purposes. For example, their heart and kidneys are used in their reproductive, circulatory, and excretion systems.

Mollusks are more varied than any other phylum. Think about it: squids, octopi, cuttlefish, nautili, clams, mussels, oysters, conch, slugs, snails — they all have many diverse species and yet they’re all still mollusks! And this is due, in part at least, to how long they’ve been around. While there’s still significant scientific debate about their precise lineages, we know that they’ve been around since the Cambrian period (541 to 485 million years ago). This has allowed them to diversify to fit in many, many niches all around the world — from the depths of the ocean to mountain tops.

Now for my favorite: SNAILS! Perhaps it’s because of my name (Gary, like Spongebob’s pet snail) but I think snails are really cool. They account for 80% of mollusks, and are perhaps the most diverse of them all. They’re found everywhere, in part because some have evolved to have gills while others have lungs.

But that’s not all! Some species with gills can be found on land, others with lungs are found in freshwater — with a select few even found in marine environments! They’re in ditches, deserts, large bodies of water and everywhere in between. Most are herbivores, but there are also omnivores and predatory snails. They’re also found in many sizes, from giant African land snails 35 cm in length to some just 1.5 mm long.

So come to HMNS to the Strake Hall of Malacology to learn everything there is about these marvelous mollusks!

World-renowned malacologist Guido Poppe visits HMNS’ “magnificent” Hall of Malacology

HMNS’ Associate Curator of Malacology Tina Petway got a special treat last week in the form of one exceptionally dapper shell expert. World-renowned Belgian malacologist Guido Poppe traveled to Houston for the express purpose of visiting our museum and surveying our utterly impressive (and at times underappreciated) Hall of Malacology.

Renowned malacologist Guido Poppe visits the HMNS Hall of Malacology | June 27, 2012It was Poppe’s first visit to HMNS and was spurred on after he met Petway at a malacology conference in Philadelphia. “We’ve never had someone at this level come and visit,” Petway said of Poppe, who has authored numerous reference books on shells in the Phillipines — where he now lives — and has named nearly 200 new species.

Renowned malacologist Guido Poppe visits the HMNS Hall of Malacology | June 27, 2012Guido Poppe with HMNS Associate Curator of Malacology Tina Petway

Poppe was particularly impressed with a yellow Spondylus, or spiny oyster, on display.

“These are really rare; there are less than a dozen in the world,” Poppe said.

And even this world-traveling diver was impressed by the world’s largest sea shell, on display here at the HMNS Hall of Malacology. “I’ve never seen one this big!”

Renowned malacologist Guido Poppe visits the HMNS Hall of Malacology | June 27, 2012To schedule your next visit to our impressive Hall of Malacology, click here for tickets, and check out our Flickr photo set of the visit here.

Oil Spills and their Impact on the Environment

Today’s Guest Blogger is Wes Tunnel, Ph.D. , marine biologist who has studied oil spills and their impact on the environment. For over 40 years he has helped develop the National Spill Control School. Dr. Tunnell, is Associate Curator of Malacology at the Houston Museum of Natural Science and Associate Director of the Harte Research Institute for Gulf of Mexico Studies and Professor at Texas A&M University-Corpus Christi. Dr.

Studying oil spills is not something many scientists do as a planned area of study for their advanced degree. Unless they are at a university near a major spill, they likely will not get engaged in studying oil spills unless one happens “in their back yard.”

That is exactly what happened to me early in my career as a marine scientist, and it is what happened to many scientists across the northern Gulf of Mexico last year (2010) with the Deepwater Horizon/Macondo spill.

Gulf Coast Oil Spill

I first had the opportunity to start learning about oil spills and their effect on the environment in the mid-1970s when our university received a grant to develop the first oil spill training program in the United States.

It took about two years of gathering information and interviewing people for the leaders of this program to establish the National Spill Control School at Texas A&M University-Corpus Christi (then called Texas A&I University at Corpus Christi). The week-long classes established for the School included specialists lecturing on the biological, chemical, and physical aspects of oil and its impact on the environment, and it also covered aspects of policy, law, social impacts, clean up techniques and strategies, and a whole realm of related topics. Attendees would see newly created movies, as well as vintage ones of previous oil spills, and they would get field experience in working with booms, skimmers, and other clean up techniques.

However, for me, this was all just book learning, and I had always been a proponent of hands-on, field oriented biology for the best understanding of any topic.

Well, on June 3, 1979, when the Ixtoc I oil well blew out in the southern Gulf of Mexico, it looked like I might get that chance. By early August, the predicted 60-day movement of oil proved true as South Texas beaches were coated for over 150 miles between the mouth of the Rio Grande to north of Port Aransas. The oil ranged from 5 to 10 yards in width and 3 to 15 inches in thickness along this entire stretch of coast. It was sickening, and I thought our beloved beaches would be ruined forever.

Working with funding from NOAA, we ran 13 transects along the length of Padre Island from Corpus Christi to the Rio Grande.

These extended from the third sandbar offshore to the upper extent of the intertidal zone. Since we knew the oil was coming, which often is not the case, we were able to do pre-spill samples before the oil arrived and then post-spill samples after it arrived.

In general, we found reductions in numbers of organisms (not numbers of species) by 80% in the intertidal zone (area where the waves wash the shore) and 50% in the subtidal zone (offshore bar and trough zone, where the waves are breaking). Although this news was devastating at first, we were pleased to find out that the beaches had recovered fully in about 2.5-3 years. A combination of fast weathering of oil (biological, chemical, and physical break down of oil) and fast reproductive abilities of most beach organisms allowed for this quick recovery.

John W. Tunnell, Jr. Ph.D.

Although this story of impact and recovery is much more complex than what is related here, we did not have sufficient funds to track the exact timing or impact, since research funds were cut off. This is typical of many large spills, so we don’t have the kind of information to answer many of the question that were flying last summer. The commitment of BP to fund the Gulf Research Initiative at $500 million total, or $50 million per year, over the next 10 years should greatly help our knowledge of dealing with and understanding future spills. Funding from NSF, NOAA, EPA, and other federal and state agencies should add to this knowledge also.

Learn more on oil spills and their impact on the marine environment from Dr. Wes Tunnel at his lecture on Monday, August 29 at the Houston Museum of Natural Science.