Sponge Species Distributions and Ecological Interactions in Apalachee Bay Kathleen Kaiser

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Honors Theses The Division of Undergraduate Studies

2014 Sponge Species Distributions and Ecological Interactions in Apalachee Bay Kathleen Kaiser

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SPONGE SPECIES DISTRIBUTIONS AND ECOLOGICAL INTERACTIONS IN

APALACHEE BAY

KATHLEEN DIANE KAISER

A Thesis submitted to the Department of Biological Sciences in partial fulfillment of the requirements for graduation with Honors in the Major

Degree Awarded: Spring, 2014

The members of the Defense Committee approve the thesis of Kathleen Kaiser defended on April 22, 2014.

Dr. Janie Wulff Thesis Director

Dr. Don Levitan Committee Member

Dr. William Parker Outside Committee Member

I would like to dedicate this thesis to my wonderful mother and all my friends who lifted me up when I was down and always encouraged me to keep striving.

ACKNOWLEDGEMENTS

I would like to thank Dr. Janie Wulff for all her amazing help and guidance. Throughout my undergraduate experience she has been there to guide and support me and I’ve grown so much as a student and as a scientist. This opportunity has just been one of many experiences I might not have ever had without all her support. I would also like to thank Dr. Don Levitan who has always been eager to help, as well as Dr. William Parker for being on my committee and helping me through the editing process. All my committee members strove to challenge me and encouraged me to be the best that I can be and for that I’m extremely grateful.

Special thanks also to all the people who have helped me along on this project. I thank

Brendan Biggs, and the whole Wulff lab team for helping with collections and identification measurements. I also want to thank Kelly Vasbinder for all her help and for being the Anna to my Elsa. Lastly I especially want to thank Gulf Specimen Marine Lab in Panacea, Florida for allowing me access to all their sponges and starfish. They were always eager to open doors and help however possible. Additionally I want to thank the Florida State University Honors in the

Major Program and the Bess H. Ward Honors Thesis Award for allowing this project to become a reality.

TABLE OF CONTENTS

ABSTRACT…………………………………………………………………………………….... 6 INTRODUCTION……………………………………………………………………………….. 7 I. DISTRIBUTION 1. INTRODUCTION………………………………………………………………. 9 2. METHODS………………………………………………………………………12 3. RESULTS………………………………………………………………………..16 4. DISCUSSION……………………………………………………………………28 II. ECOLOGICAL INTERACTIONS 1. INTRODUCTION……………………………………………………………….33 2. METHODS ……………………………………………………………………...35 3. RESULTS………………………………………………………………………..37 4. DISCUSSION…………………………………………………………………....39 CONCLUSIONS AND DISCUSSION………………………………………………………….43 REFERENCES: SPONGE IDENTIFICATION REFERENCES………………………………………………….44 LITERATURE REFERENCES…………………………………………………………………47

ABSTRACT

Despite their simple appearance sponges are extremely diverse and complicated in their interactions with other organisms, and they are extremely difficult to identify to species. Often sponges of the same genus or body shape have very different ecological interactions, so proper identification of the species is a necessity. With proper identification, it’s possible to see what species characteristics may influence the ecological interactions.

One of the major goals of this study was to look to see if distribution patterns had shifted in years since previous studies. I looked at sponges from four different locations and identified them to the lowest taxonomic level possible. I include detailed descriptions on the identification process including any discrepancies discovered while attempting to identify the species. Overall, we found 37% of the sponge species reported in 1963 by Little and 36% of the sponge species reported by de Laubenfels in 1953. We also added several species neither had reported.

I also looked at some of the ecological interactions in this area and tested starfish feeding choices of local sponges. For Echinaster spinulosus there was no clear pattern of rejection and acceptance, but a gradient of consumption, from 100% of trials to 0% of trials.

Overall our findings reflect the complicated and diverse nature of sponges in both the identification process and their ecological interactions. Species identification and experimental results offer a tantalizing preview of how interesting further delving into the sponge distribution patterns and ecological interactions in Apalachee Bay will be.

INTRODUCTION

In order to discuss the distribution of sponge species, it’s important to understand how to properly identify species. This then helps identify the ecological interactions that occur in this system. Specifically, I’ll examine the interactions between local starfish and sponges, and discuss the interactions we observed in the field.

Sponges play a crucial role in their environments since they are often important sources of structure for other organisms (Wulff 2006a). Some organisms residing within sponges include polychaete worms, copepods, isopods, amphipods, and even barnacles (Wulff 2006a). Large sponges can also be important shelters for juveniles of the Caribbean spiny lobster, Panulirus argus in seagrass beds (Wulff 2006a).

Sponges also have unique filtering capabilities (Reiswig, 1971, 1975). Sponges provide a unique ecosystem resource as one of the only organisms that can filter bacteria out of the water column (Reiswig, 1971, 1975). By taking in water through ostia, their incurrent canals, they filter out all the small food particles by using choanocytes, or collar cells. These “collars” can trap small particles which filters the water. Locally, their filtering capabilities could help control the outbreak of phytoplankton blooms (Wulff, 2013).

It’s important to understand that sponges are an extremely diverse group of organisms.

There are over 8500 recognized species worldwide (van Soest 2012). Every year there are still thirty-five to eighty-seven new species being described (van Soest 2012) so our understanding of diversity is constantly changing for these organisms.

Another important aspect to understand about sponges is that species which closely resemble each other in color or growth form can have completely different ecological interactions. One really clear example of this is the two closely related species, Tedania klausi

7 and Tedania ignis. These two species are so similar in their growth form, color, and skeletal composition that until 2006 these species were considered to be the same (Wulff 2006b). The ecological interactions, however, are dramatically different between the two species. In Wulff’s

2006 study, she reported that in feeding trials with Oreaster starfish T. klausi was consistently rejected by the starfish, suggesting the sponge may be chemically defended. T. ignis in feeding trials was consumed at every opportunity by Oreaster. When she examined the habitats for the two species she also found this distinction; T. klausi was found in both the seagrass and mangroves, while T. ignis was only found in the mangroves. Another interesting distinction was noted when a pathogen infected T. klausi, T. ignis was resistant to this pathogen (Wulff 2006b).

Because sponges play many important roles in their ecosystems, it is also very important that we identify the species accurately because species can differ substantially in their ecosystem roles and ecological interactions. Bearing this in mind, I define my two primary goals for my study: 1) to determine which sponge species live in the Apalachee Bay area now, and compare this present distribution with previously documented distributions, and 2) to examine the ecological interactions of the sponges in order to compare them with studied ecological interactions in the tropical portions of the western Atlantic.

I: Distribution I.1: Introduction

Very little is known about the sponge species distribution in Apalachee Bay. Only a handful of studies have ever attempted to examine the distributions around this area (Little,

1963; de Laubenfels, 1953; Storr, 1976). Because of the lack of recent studies we know little about what species are present and what their interactions are in this area. This area is especially interesting because of the mix of tropical and temperate faunas for all marine organisms.

In order to see how many species are in this system we first need to find the distribution of sponge species, and then compare the species we found to those reported in prior work. In order to find the distribution of sponges, it’s necessary to have proper species identification.

Several important factors are crucial to understand involving the identification of sponges. Sponge species can vary in a few or many different factors, including growth form, color, interactions with other organisms, and skeletal components (Rützler, 1978). In a lot of the current literature only one of these characteristics is taken into account, which has distorted our knowledge of species distributions. One species example for this is Halichondria panicea which appears to have a global distribution (van Soest 2014), which was considered to include the Gulf of Mexico as well as sites on the other side of the world. It’s unlikely that this species truly has a global distribution, due to different temperatures and habitats as well as geographic barriers to dispersal, which is why thorough identification is so important. There are several reports of species that were thought to be the same all over, but on closer scrutiny are actually different in each ocean (Boury-Esnault, 1999). Studies by Little (1963) and de Laubenfels (1953) were exceptionally useful in identifying sponges, since they incorporate multiple factors instead of basing a species name off one characteristic. Both of these studies incorporated not only a list of species but clear descriptions in their reasoning for the identification. For our study, we initially

9 looked at the skeletal components then considered all the other factors before identifying a species by name.

Skeletal components of sponges are typically composed of both silica spicules and spongin fibers made of Keratin. The identification process (outlined in detail within the methods) is a very complex and difficult process that requires a combination of expertise and a thorough library of identification references including accurate and detailed descriptions of species. The multitude of different spicule types, sizes, and variations makes identification a real challenge for many sponge species. Often the observation of skeletal elements such as spicule arrangement or spongin fiber arrangement is needed to differentiate between species.

The morphology between different individuals of the same species can vary dramatically depending on the species. For example, some species are easy to identify in the field due to striking and unique characteristics. Other species, however, can have huge ranges in color that make the identification very difficult. For Demospongia, silica spicules along with spongin fibers make up the skeletal components, so these are used to distinguish species. The combination of different spicules can usually direct us toward an Order of sponges. For example, the Order

Poecilosclerida can be determined based on the presence of chela microscleres which is unique to the order (Systema Porifera 2002). I can then determine if the sponge is in the Genus

Lissodendoryx based on the presence of sigma, tylotes, and styles. Other species however, like those within the Order Haplosclerida, may be composed of only one kind of megasclere, so how the spicules are arranged in the skeleton makes all the difference, along with color and texture descriptions. For species lacking spicules the fiber arrangement can be extremely useful for identification. There are many different aspects of sponge skeletal components useful for

10 identification, and for a proper and confident identification, as many different ones as possible should be examined (Rützler, 1978).

Proper species identification allows us to find the distribution of sponges in Apalachee

Bay. Once we have an understanding of the distribution, we can compare the species found to those reported in earlier work. Additionally, we can report on any new species found and discuss the potential reasons for their appearance. There is also the possibility that distributions have shifted northward for tropical species due to climate change (Storr 1976; Wulff 2006a, 2012).

Investigating the species distribution in this area allows us to investigate the different observed and potential ecological interactions, since so much has been done in the Caribbean and the

Florida Keys. Many species Janie Wulff has worked with in the Caribbean also live in the Gulf but sponge interactions have been rarely studied in the Gulf of Mexico. These species may interact differently with their abiotic and biotic environment in the Gulf of Mexico.

I.2: Methods

Sponge Distribution and Species Identification.

Collections were taken from four different locations around Apalachee bay. Sites include:

1. Offshore of St. Marks, 12-18ft deep, with specimens collected via snorkling in 2003 by sponge expert Janie Wulff 2. Offshore from Turkey Point, 42ft depth, with specimens collected in 2011 in a complete census of a permanent census plot performed by Brendan Biggs 3. St. Joseph Bay, shallow depth 0-6ft, in a focused faunal survey in 2013 performed by myself 4. Specimens collected from holding tanks at Gulf Specimen Marine Laboratory which performs collections in the middle of Apalachee Bay at four different locations. Trawling at 14ft and 18ft, with diving at 20ft and 45ft. A collection by Jennifer Schellinger was also collected from this area via diving. This one collection was solely in order to have sponge tissues collected before oil mixed with dispersant arrived in this area. Because of this there was a lower thoroughness (figure 2, and explanations below) for the collection

Figure 1: Collection Locations around Apalachee Bay: In red St. Joseph Bay 29.8650 N, 85.3871 W; Gulf Specimen Marine Lab’s collecting stations are indicated by the green circle; St. Marks indicated by the orange circle; Turkey Point 29.773750 N, 84.482570 W in purple.

From St. Marks, St. Joseph Bay, and Turkey Point, pieces of individual sponges were collected and dried then brought back to the lab for identification. Many specimens from Turkey

Point were identified on sight by Brendan Biggs, with small pieces, of species for which the field identification was uncertain, brought back for identification using spicule slides. Specimens from

J. Schellinger were frozen, which preserved the coloration and structure of the samples, so descriptions for those sponges were possible only from the samples. Gulf Specimen Marine Lab collected whole individuals, so for many of the sponges full descriptions on the color, shape, and texture were possible.

Because of the difference in collection strategies and scrutiny I ranked each site by thoroughness (Figure 2) with high sites indicating a complete census, where every sponge was included, and medium sites indicating that some types of sponges may be missing. Missing sponges may be encrusting or crevice residing individuals that might go unnoticed or uncollected. This is likely the case with the Gulf Specimen sites since they often collect larger individuals to return to their tanks, avoiding small encrusting, hidden, or rare species (Personal communication with C. Rudloe and personal observations).

Figure 2: Details of collection locations including depth, habitat, thoroughness of collection, and map indicator color.

Spicule slides are created by first cutting a small piece from the sponge brought back for identification. This piece should incorporate both the outer and inner parts of the sponge, however if the piece is too big the slide will be overcrowded with spicules making measurements difficult. These pieces are then put in a labeled test tube and soaked overnight in concentrated household bleach. This dissolves all the tissues of the sponge leaving only the spicules.

Occasionally two or three soakings of beach might be necessary depending on the amount of spongin binding the spicules together and the density of the sponge tissue. Once the tissues are dissolved the samples are spun in a centrifuge to settle the spicules to the bottom of the tube. The bleach is carefully pipetted out, taking care not to disturb the pellet of spicules, and water is added, breaking up the pellet and diluting any remaining beach. Three water rinses are performed each time spinning the sample before taking out any water. After the third rinse the samples are spun and most of the water is removed, then the pellet is re-suspended, usually by tapping the tube carefully against a table, and small amounts of water are added to break up the pellet further. The sample is then spilled out onto a slide and spread out evenly. We then dry the sides by placing them on a slide warmer and allowing all the water to evaporate. Once the slide is dry we use permount to glue on a coverslip and also give the spicules definition. Detailed drawings of the spicules are done using a camera lucida on the microscope and length and width measurements of the different spicules are taken at the highest magnification possible, while still having the whole spicule in the view. We make drawings and measurements of all the spicule types and sizes, then species are identified using primary literature and original descriptions of sponge species. Dr. Janie Wulff has an extensive collection of primary literature that includes hundreds of key sponge systematics references published since 1864, which is an essential resource for proper species identification.

For some species spicule slides do not provide sufficient information to arrive at a species identification, and a skeletal preparation is needed. To prepare a skeleton, thin slices of the outer tissue are taken both vertically and horizontally. These are then mounted on a slide with permount added, allowing us to see the spicule arrangement in the skeleton, which is then compared to identification references.

Specimens were identified to the species level when possible and to the genus if there were discrepancies between published species descriptions and material from our specimens. My results include extensive notes on all identified species where concerns or discrepancies were noted. Species were also cross checked in the World Porifera Database

(http://www.marinespecies.org/porifera/index.php), which is a database of sponge species kept up to date by a panel of sponge experts from around the world.

For an understanding of the past species distribution we used two studies: Little (1963) and de Laubenfels (1953). These two studies were chosen since de Laubenfels is a known sponge expert and Little worked closely with other sponge experts to ensure that his distribution reports were accurate. Because of the expertise and thoroughness of these previous workers, we feel confident that these studies represent a fairly complete idea of the distribution of species fifty years ago. De Laubenfels (1953) study consisted of four stations in this area ranging in depth from 6.5m to 14.5m. Little’s (1963) study consisted of eighteen stations with depths ranging from 0m on shore to 14.5m.We compared their findings to ours, split by site.

I.3: Results

Sponge Species Identification and Distribution

The following is a list of the 31 species identified by skeletal components, live color descriptions, growth form descriptions, additional field notes, along with identification notes on other species we investigated, as well as any uncertainties or variations from the primary literature we used to identify the species. Table 1 displays those species reported by Little

(1963) and de Laubenfels (1953) as well as all our species we identified either by skeleton components, sight, or a combination of the two. Two distinctions were necessary to add when we were identifying the species. “cf.” implies our specimen is likely closely related to this particular species but it was not an exact match. These specimens may be geographic variations or potential sister species. “sp.” means we were confident in the genus but there were no described species that matched our sample. We took a great deal of care to include all the discrepancies amongst our identification efforts. Often studies performed by non-sponge experts include an unreliable list of species based of photographs, which isn’t a conclusive method of identification.

Species:

Aplysina fulva (Pallas, 1766) Specimens were found at Gulf Specimen, and were visually seen offshore at Turkey Point. This common sponge is known for its finger-like branches that are a golden yellow color. A. fulva also has characteristic golden spongin fibers. The specimens we found were the same texture, color and shape as A. fulva, so we are confident in the identification. An interesting color change occurs when A. fulva touches air. The tissue turns black. Tissue also turned black when starfish fed upon A. fulva, as noted in the second part of this thesis.

Igernella notabilis (Duchassaing & Michelotti, 1864)

Previously known as Darwinella joyeuxi Topsent, 1889, this sponge is a beautiful reddish-pink color with a soft and spongy consistency found at Gulf Specimen, and confidently identified in the field at Turkey Point. One of the other species we looked into was Darwinella mulleri as described by de Laubenfels in 1950. Little suggested that these two species may in fact be one species (Little 1963). Cross-checking with the World Porifera Database revealed an inaccurate recording of D. mulleri in the Gulf of Mexico and a genus transfer for D. joyeuxi, so we are referring to our species as I. notabilis.

Amphimedon compressa Duchassaing & Michelotti, 1864 Our sample came from Gulf Specimen. Little’s specimen had oxea with an average of 136µm and a range of 115 to 157µm (Little 1963). Our average length for oxea was slightly higher with 151µm, however our range was still close with 124 to 162µm. Field notes suggest Amphimedon compressa as the species. Since I didn’t have the original specimen, I couldn’t make a completely confident identification, although our spicule size, shape, and range do match. This particular sponge is a distinctive species in the field and there are no other tropical Atlantic species that share the smooth surface, branching growth form, and crimson color, so based on the field notes suggestion we can be very confident, but the original specimen would have bolstered that confidence even more.

Haliclona cf. tubifera (George & Wilson, 1919)

This specimen came from Gulf Specimen, although I didn’t have the original specimen and only had minimal field notes and a spicule slide. Field notes described this specimen as a grey sponge with small volcanoes. The spicule slide consisted of all oxea. Our spicule shapes and range of 146 to 164µm matched those presented in de Weerdt’s paper of 104-171µm. (de Weerdt, 2000, 1991). Without a skeleton slide we couldn’t be confident in the species identification so we named this sponge H. cf. tubifera with the caveat that a skeletal prep was not possible.

Haliclona (Rhizoniera) curaҫaoensis (van Soest, 1980) This is a light purple-blue-gray sponge consisting of all oxea from 85-138µm. Our particular specimen was found frequently, encrusting on pen shells in shallow waters at St. Joseph Bay. We looked at five different Haliclona species; H. cuaҫaoensis, H. melana, H. vermeuleri, H. lehnerti, and H. mucifibrosa, which we first picked based on spicule shape and relative sizes (de Weerdt 2000). We narrowed the list to H. lehnerti, H. vermeuleri, and H. cuaҫaoensis after further scrutiny of shape and size along with color. H. cuaҫaoensis was finally chosen. Our sponge had the same texture and slime-like, almost cotton candy-like way of being pulled apart, along with the characteristic color, and oscule shape.

Niphates erecta Duchassaing & Michelotti, 1864 This specimen came from Gulf Specimen with field notes suggesting N. erecta. We compared measurements of our specimen (172-227µm) to those recorded by Sven Zea (161-247) and those of van Soest (154-232) (Zea 1987; Van Soest 1980) to confirm the field notes suggestion of N. erecta.

Tedania ignis (Duchassaing & Michelotti, 1864) This is a dull orange sponge with characteristic hairs on the tylote heads. Janie Wulff collected many different individuals of this species from the St. Marks site in 2003. We compared the size ratio between the style and tylotes to differentiate between the species T. ignis and T. klausi. On average our ratios were closer to those of T. ignis so we identified this species as such, with the caveat that the spicules on the whole are smaller than those found in other parts of the Caribbean (Wulff 2006b) with the average Style length of 228µm and the average tylote length of 206µm compared to the Belize average style length of 261µm and the average tylote length of 226µm (Wulff 2006b).

Lissodendoryx (Lissodendoryx) spinulosa Rützler, Piantoni & Díaz, 2007 Our specimens were found at all sites. Our spicules consisted of Subtylostyle 132-139-168µm by 1.6-3.68-4.8µm, tylotes 177-194-213µm, two size classes of sigma with I:36-39.47-44µm and II:11-12.57-16µm, and two size classes of isochela I:31.2-36.87-42.3µm and II:8.8-10.67-12µm In Little’s previous study he reported finding Lissodendoryx isodictyalis, though with a rather large size range for the microscleres, reporting 16-28µm. Our measurements were close to some that Little reported, however Rützler, Piantoni & Díaz, (2007) made clear the distinctions between L. isodictyalis, L. carolinensis, and L. spinulosa. In comparison to L. spinulosa we recorded our specimens with two size classes of anisochela, instead of three. Though the range of means reported has an overlap of the first and second size classes, some specimens do not report the second size class. In the diagnosis, Rützler defines it with two size classes of isochela and sigmas. L. spinulosa was most similar to our specimens in size range and shape for all the spicule types we found. Many subtylostyles found in our samples displayed small spines on the heads which match the description made by Rützler, Piantoni & Díaz (2007).

Lissodendoryx (Lissodendoryx) sigmata (de Laubenfels, 1949) We found specimens at all locations with the color ranging from a soft yellow or yellow brown to orange. All the specimens lacked styles and had the characteristic large sigma with two size classes of sigma and chela. The descriptions and spicule sizes matched those recorded by (Rützler 2007).

Clathria (Clathria) prolifera (Ellis & Solander, 1786) Previously known as Microciona prolifera (Ellis & Solande, 1786), our specimen was a red orange sponge with what resembled branches, from the Gulf Specimen tanks. One specimen looked as if it was encrusting on a clam shell then extended the branches off the shell about an inch. The primary literature we referenced was van Soest’s paper on different Poecilosclerida species (van Soest 1984b). Clathria prolifera was the only species described as red and not entirely an encrusting species. The spicules were also a close match though our isochela were smaller, averaging 9.12µm. Toxa and acanthostyles were also larger, averaging 82.2µm and 95.9µm respectively. Our subtylostyles ranged from 221 to 372µm. Van Soest’s reported measurements had subtylostyles 160-252.8-342 and smooth styles from 141-387, acanthostyles 56-74.2-86, palmate isochela 12-14.9-17, and small thin toxa 15-20.6-27.

Clathria sp. This is a dark red-orange sponge, found encrusting over pen shells and limpets on the pen shell in St. Joseph Bay. On the limpets, it appeared smooth whereas on the pen shell it appeared bumpy. Its spiculation consisted of subtylostyles from 184 to 627µm with some heads displaying spines as well as small isochela averaging 18µm with very distinct heads that looked like top hats.

Eurypon clavatella Little, 1963 The specimen is a yellow ball-like sponge with a slightly rough or fuzzy surface. Our sample resembled a Cinacyrella species in appearance with the ray-like appearance of the inner tissue. The sponge was missing the characteristic long radial spicules, and the actual spicules consisted of only styles to tylostyles with some acantho-subtylostyles, never larger than 475 micrometers. Little described E. clavatella as a thin encrusting species which isn’t characteristic of our sponge though the spicules match. Our measurements matched those Little reported with tylostyles 249- 384-470µm and acanthostyles 75-102-145µm (Little 1963) so with that we consider our specimen this species, with the caveat that only the spicules match and the growth form appears different. It’s possible the sample Little took was early in development and the growth form is actually massive or ball shaped.

Mycale cf. angulosa (Duchassaing & Michelotti, 1864) These specimens were all from St. Marks and consisted of tylostyles averaging 241µm and anisochela of three size classes averaging 38µm, 20µm, and 12µm. Van Soest described M. angulosa with isochela as the smallest size class (van Soest 1984b)which our specimen didn’t fit, however all the other measurements seemed to match. The fact that the smallest size class for M.

19 angulosa chela are isochela is very odd considering all other species of Mycale with multiple size classes of chela all contain anisochela. I attempted to find another description, however I was unsuccessful. Our measurements were also similar to M. citrine but the subtylostyle sizes (avg 382µm) are far off and M. citrine has never been described in the Gulf of Mexico. We also looked at the original description of M. angulosa to verify if there were in fact isochela (Duchassaing 1864). The original description called Mycale under the genus Acamas but only gave full descriptions for two species M. laxissima and M. violacea, the second of which is now Hytios violaceus. M. angulosa was originally described as Pandaros angulosa however no spicule measurements were presented. De Laubenfels also recorded measurements for M. angulosa but later evaluation re-identified his specimen as M. laxissima (de Laubenfels 1936a). Our specimen didn’t contain any isochela, much less as the smallest size class so we’ve identified the specimens as Mycale cf. angulosa, with the caveat that the smallest size class of chela are anisochela and not isochela.

Artemisina melana van Soest, 1984 This sponge was described as “dark black fingers” in the field notes and consisted of Styles 212- 352µm chela 15.18-17.71µm and toxa. The measurement and spicule types were consistent with A. melana, however this is an encrusting species. This specimen could have actually been a thin black sponge overgrowing a branching sponge without spicules, though since we don’t have the original specimen it’s hard to determine if this is the case. Given that there are very few black sponges with this spicule compliment we have decided to stay with A. melana.

Axinella polycapella de Laubenfels, 1953

Commonly called orange devil’s fingers at Gulf Specimen this is a vibrant orange branching sponge. We prepared a spicule slide to verify it was A. polycapella and compared our ranges to those recorded by Alvarez, van Soest, and Rützler (1998) and the size range and shape matched.

Axinella pomponiae Alvarez, van Soest, & Rützler, 1998 Red branching Axinella, commonly called red devil’s fingers at Gulf Specimen, this sponge was also found in Schellinger’s site. We looked at A. waltonsmithi, and A. polycapella too, however our styles matched A. pomponiae and so did the color description (Alvarez et. Al 1998). It’s also the accepted name and it’s been confirmed in the Northern Gulf of Mexico.

Axinella waltonsmithi (de Laubenfels, 1953) Orange fan shaped sponge found at Gulf Specimen and the spicules match those reported by Alvarez, van Soest, and Rützler (1998).

Halichondria (Halichondria) corrugata Diaz, van Soest & Pomponi, 1993 Light green to a darker dull green sponge, sometimes specimens had spire-like formations while those found on decorator crabs were lumpy. This sponge was found both at Gulf Specimen and at St. Joseph Bay where it’s typically found growing on decorator crabs. Little reported this sponge as H. panicea and remarks it resembles H. Bowerbanki (Little 1963). This sponge was also commonly called the “bread crumb sponge” which H. Bowerbanki is sometimes called. Diaz 1993 reports on H. corrugata and describes Halichondria panacea from Little’s census in 1963 as a synonymous sponge, describing how it differs from H. panicea in its characteristic grooved oscular chimneys. Both the spicules and the skeleton structure matched those reported by Diaz, Pomponi, and van Soest. Based on these findings, I chose H. corrugata.

Halichondria sp. (orange) This sponge was a dull orange color consisting of all oxeas of a large size range, many of them quite large, which is typical of the genus Halichondria. We checked Diaz et. all 1993 but couldn’t find a successful match.

Halichondria sp. (yellow)

One specimen’s description is a small yellow encrusting sponge and the other description is a light yellow sponge with spires. Both of the specimens were found at Schellinger’s site. The spicules consisted of all styles to subtylostyles in a large range. We looked at Hymeneacidon heliophila (Diaz 1993) but its size range (130-450µm) is much smaller than our specimens (260- 1008µm).

Ptilocaulis marquezii (Duchassaing & Michelotti, 1864) Described as an orange sponge with tall branches, there were no styles present in the spiculation of this sponge. It isn’t an Axinella species based on the descriptions in Alvarez et al 1998. We considered Ptilocaulis marquezii, which fit our size range, but our specimen didn’t have any of the larger spicules. We also eliminated P. walpersi as a possibility because our specimen consisted more of oxea and strongylostyles than styles and strongyloxea. P. marquezii is described as a red orange branching sponge which matches our description, and since the overall growth form is a good character in Axinellidae we are using this as the species name.

Spheciospongia vesparium f. pallida (Lamarck 1815) This sponge is commonly referred to as the loggerhead sponge and is usually a massive black sponge. There is a yellow version of the species, as our specimens demonstrate. Our specimens

21 were found both at St. Marks and Gulf Specimen. De Laubenfels remarked on finding a bright yellow version of the loggerhead sponge and believed there to be a yellow race in northern gulf regions (Vicente 1991). Vicente and Rützler also remarked on the differences within Spheciospongia vesparium. They described two forms: the typical form and a yellow form dubbed pallida. Both were collected from Puerto Rico and they commented that the yellow version mostly differs in external morphological characteristics and in habitat. S. papillosa is the only other similar sponge species reported in the Gulf of Mexico (Rützler 2009) which didn’t match our specimens. Close scrutiny of the spirasters reveals the difference between species of Spheciospongia.

Spirastrella cf. coccinea (Duchassaing & Michelotti, 1864) Our specimens were collected from Gulf Specimen, Turkey Point, and St. Marks with field notes describing the sponge as orange. There are three Spirastrella species that we focused on in the Caribbean but all of them have different color descriptions. S. mollis and S. hartmani are salmon brown, and S. coccinea is a vermillion red color, none of which seem to match our color description. As far as spicules, our species closely resembles those reported for S. coccinea by Boury-Esnault et al. (Boury-Esnault 1999). Duchassaing & Michelotti first described this species as a dramatic red color, however other reports have called it an orange color. Little describes S. coccinea as orange in life, and remarked on differences in spicule ranges but left his specimen as S. coccinea since it didn’t seem like enough to separate the species. S. coccinopsis was also reported by de Laubenfels but not found by Little who remarked how de Laubenfels believed it to be similar to S. coccinea since it differs primarily in color and size. Spirastrella coccinopsis, coccinea, and phyllodes are the only ones in the Rützler chapter on sponges in the Gulf of Mexico (Rützler 2009) and S. phyllodes is currently under review on the World Porifera Database. We use S. coccinea with the caveat that the spicules are a close but not great match, and the color is different than the original description for the species.

Placospongia intermedia Sollas, 1888 Placospongia species are very distinct in their appearance and in their spicule compliment. We found this species at all the sites except St. Joseph Bay. Little identified a species as P. carinata (Little 1963). This species is no longer accepted for the Gulf of Mexico based on inaccurate records, according to the Word Porifera Database. We also looked at P. melobesoides which is a species de Laubenfels recorded (de Laubenfels 1953a), but the spicule sizes are much too large and it’s a deeper water species.

Cliona cf. celata Grant. 1826 This sponge was collected from Gulf Specimen and Turkey Point with spicules that match C. celata, however reports of it in the Gulf of Mexico have been described as inaccurate. The main

22 distribution seems to be in the Adriatic. Little has reported it in the Gulf and all our samples fit within the size ranges for C. celata and C. viridis, however color and morphology descriptions support C. celata (Little 1963)

Tethya sp. This was an orange ball-like sponge consisting of strongyloxea and several size classes of asters including large spherasters, and small oxyasters and tylasters. The general spicule complement pointed us toward the Tethya genus where we then looked at Tethya actinia, Tethya diploderma, and Tethya repens since these were reported in the Gulf of Mexico (Rützler 2009). I went through the original description of T. actinia from de Laubenfels 1950 and his reports have strongyloxeas around 2000micrometers which must be a mistake. The average spheraster diameters reported were 30micrometers which were much smaller than the averages from our samples. I also contemplated T. diploderma however the coloration is usually different, typically described as a lemon yellow. I looked at the newly described Tethya ignis from Ribeiro & Muricy, (2004) and found our specimen matched the spicule measurements very closely with the average spheraster diameter of 53micrometers. T. ignis was described from one specimen found in Brazil, south of the Amazon River so there is some hesitation in calling our sample T. ignis. Upon further review of our oxyasters I found that our specimens were much smaller than those of T. ignis. Tethya seychellensis (Wright) Sollas was also very similar but again the oxyasters are too large when compared to our specimens. I couldn’t find adequate measurements for T. diploderma even from the original description which required translation. Despite many references to T. diploderma being found in the Gulf of Mexico I was unable to find any spicule measurements. With that and the many other dead ends, we resorted to simply naming this species Tethya sp. since we couldn’t make a confident assertion to any one species.

Suberites sp. This was a small orange-brown encrusting species consisting of several size classes of subtylostyles. Bulbous heads on the subtylostyles suggested Terpios or Suberites. There were multiple size classes of subtyostyles so the Terpios genus was eliminated (Systema Porifera). We looked at Pseudosuberites and Suberities (Rützler and Smith 1993). The obvious difference between the two seemed to be the surface spicule arrangement where the spicules were either horizontal to the surface or perpendicular to the surface, creating a velvety texture. Perpendicular arrangement would indicate Suberites and the horizontal arrangement would indicate Pseudosuberites. Our specimens had the perpendicular pattern which led us to Suberites. We weren’t able to identify the exact species so we left the specimen at the genus level.

Aaptos (cf) pernucleata (Carter, 1870)

Yellow brown lumpy sponge with zoanthids that had a huge size range of tylostyles from 226µ to 1008µm. In our analysis we were between A. pernucleata and A. bergmani. Storr (1976) reported finding A. bergmani whereas de Laubenfels reported (1953a) finding A. pernucleata. Upon final decision we chose A. pernucleata based on more similarities with our specimen.

Geodia gibberosa Lamarck, 1815 The spicule complement of this sponge firmly put it in the Geodia Genus and within that genus we looked at three species; Geodia gibberosa, Geodia papyracea, and Geodia neptuni. Of these, the spicule measurements seemed to closely match G. gibberosa, which is the basis for our identification choice (Hajdu 1992). This sponge was found in deeper waters by Gulf Specimen.

Cinachyrella alloclada (Uliczka, 1929) Our specimens were yellow and typically ball-shaped and very distinct, with spicules sticking out and small balls of sponge tissue on the middle and ends of the visible spicules projecting from the surface. These characteristics suggested Cinachyrella, and after looking at the surface of the specimens we narrowed it to C. alloclada or C. kuekenthali but the specimen was much too small for C. kuckenthali and at closer inspection was confirmed to C. alloclada. This sponge was found at all sites except St. Joseph Bay.

Arthuria canariensis (Miklucho-Maclay, 1868) This sponge was offshore of Turkey Point and was described as a yellow-green color. Little reported finding Leucosolenia canariensis, and his description of both the color and the spicule complement and sizes matched those we found (Little 1963). Arthuria canariensis is the currently accepted name for Leucosolenia canariensis, according to the World Porifera Database.

Table 1: Sponge Species Distribution: A listing of the sponges reported by both Little 1963 and de Laubenfels 1953. X indicates a confident identification while B represents a visual identification made in the field. Red names were outside our census area from Little’s findings. Accepted St. Turke Gulf Order Little 1963 Species St. Josep y Specime de Laubenfels names Marks h Bay Point n Dictyoceratid Spongia Spongia a barbara barbara Dictyoceratid Spongia Spongia Spongia a graminea graminea graminea Dictyoceratid Ircinia Ircinia Sarcotrgus

24 a fasciculate fasciculate fasciculatus Dictyoceratid Ircinia ramose Ircinia ramosa a Dictyoceratid Hippospongia Hippospongia Hippospongia a lachne lachne lachne Dictyoceratid Hippospongia Hippospongia Hippospongia a gossypina gossypina gossypina Dictyoceratid Aulena Hyattella a columbia cavernosa Dictyoceratid Ircinia Ircinia Ircinia a campana campana campana B Dictyoceratid Ircinia Ircinia a strobilina strobilina B Dictyoceratid Dysidea Dysidea a etheria etheria B Dictyoceratid Dysidea Dysidea a crawshayi variabilis Dictyoceratid Euryspongia Euryspongia a rosea rosea Verongida Aplysina fulva B X Verongia Verongia Aplysina Verongida longissima longissima cauliformis Aiolochroia Verongida Ianthella ardis crassa Dendroceratid Darwinella Darwinella Igernella a joyeuxi mulleri notabilis B X Haliclona Amphimedon Haplosclerida rubens compressa x Haliclona Haliclona Amphimedon Haplosclerida viridis viridis viridis Haliclona cf. Haplosclerida tubifera x Haliclona Haplosclerida curaҫaoensis X X X Niphates Haplosclerida erecta X B Callyspongia Callyspongia Callyspongia Haplosclerida vaginalis vaginalis vaginalis B Callyspongia Callyspongia Haplosclerida repens fallax Haliclona Haplosclerida Adocia neens implexiformis Poecilosclerid Coelosphaera Coelosphaera a fistula fistula Poecilosclerid Rhizochalina Oceanapia a oleracea oleracea

Poecilosclerid Holoplocamia Antho a delaubenfelsi delaubenfelsi Poecilosclerid Cyamon Cyamon a vickersi vickersi Poecilosclerid Merrianmium Phorbus a tortugasensis amaranthus B Poecilosclerid Tedania ignis Tedania ignis a X Poecilosclerid Lissodendoryx Lissodendoryx a isodictyalis isodictyalis Poecilosclerid Lissodendoryx a spinulosa X X Poecilosclerid Xytopsene Lissodendoryx a sigmatum sigmata X X X Poecilosclerid Microciona Clathria a proliefra proliefra B X Poecilosclerid Clathria sp. a X Poecilosclerid Eurypon Eurypon a clavatella clavatella x Poecilosclerid Thalyseurypo Thalyseurypo Clathria a n vasiformis n vasiformis vasiformis Poecilosclerid Carmia Mycale a macilenta macilenta Poecilosclerid Mycale cf. a angulosa x Poecilosclerid Toxemma Biemna a tubulata caribea Poecilosclerid Artemisina a melana X Axinella Axinella Axinella Halichondrida polycapella polycapella polycapella X Axinella

Halichondrida pomponiae X X Homaxinella Homaxinella Axinella Halichondrida waltonsmithi waltonsmithi waltonsmithi B X Halichondria Halichondria Halichondrida panicea corrugata X X Halichondrida

Halichondrida sp. (Orange) x Halichondrida

sp. (yellow Halichondrida encrusting) x Ptilocauis

Halichondrida marquezii X Spheciospongi Spheciospongi Spheciospongi X (f. Hadromerida a vesparia a vesparia a vesparium pallida X

) Spirastrella Spirastrella Hadromerida coccinea coccinea X X X Spirastrella Spirastrella Spirastrella Hadromerida coccinopsis coccinopsis coccinopsis Anthosigmell Anthosigmell Hadromerida Cliona varians a varians a varians Placospongia Placospongia Hadromerida carinata intermedia X X X Hadromerida Cliona celata Cliona celata x x Cliona Cliona Cliona Hadromerida caribboea caribboea caribbaea Hadromerida Cliona truitti Pione truitti Cliona Pione Hadromerida vastifica vastifica Hadromerida Cliona lampa Cliona lampa Pione lampa Hadromerida Cliona viridis -Cliona viridis Tethya -Tethya Hadromerida aurantium aurantium Hadromerida Tethya sp. x x Hadromerida Suberites sp. x Aaptos (cf) Hadromerida pernucleata x Spongosorites Hadromerida suberitoides X Unimia Unimia Erylus Astrophorida trisphaera trisphaera trisphaerus Geodia Geodia Geodia Astrophorida gibberosa gibberosa gibberosa X Cinachyra Cinachyrella Spirophorida alloclada alloclada X X X Chondrilla Chondrilla Chondrosida nucula nucula Leucosolenia Arthuria Chondrosida canariensis canariensis X Halisarca Halisarca Chondrosida purpura purpura

We found 7 of the 19 species that de Laubenfels found in this area. We found 20 of the 53 species that Little found in this area.

I.4 Discussion Distribution and the Associated Challenges of Identification

My original motivation in this study was to work toward a comprehensive understanding of the sponge species diversity in this area, and to compare the current sponge fauna with that reported previously, to see if there was a response to climate change. These data represents only the first step toward that goal. Fully accomplishing this goal will require revisiting and completing censuses for the exact sites used in both de Laubenfels 1953 study and Little’s 1963 study. This would require additional resources and time that were unavailable at the time of this study. With this in mind, these data represents the beginning of our understanding of how the species distribution has changed over the last sixty years.

When we look at de Laubenfels’ study in 1953 and compare his reported distribution to ours it is obvious that there are differences (Table 1). Overall, we found only 7 of the 19 species reported by de Laubenfels. Of the species that we found, most of the accepted names are for species that are typically members of the Caribbean fauna. These species include Ircinia campana, Callyspongia vaginalis, and Geodia gibberosa. Temperate zone sponge species,

Axinella polycapella and Axinella Waltonsmithi were also reported by both de Laubenfels’ study and ours. When we compare our distribution findings to Little’s, we also see a combination of

Caribbean and temperate fauna. In total we found 20 of the 53 species Little reported.

The two obvious groups that seem to be missing from our census, yet appeared in

Little’s, are many of the Keratose species as well as many of the Cliona species. We were certain of the presence of the genera Ircinia and Dysidea, however we didn’t include them because we were not confident in assigning them to a particular species. Likewise we also had several specimens characterized by spicules that were only oxea, which clearly indicated they were in

28 either Halichondrida or Haplosclerida, but we were unable to identify them to a species without the living sponge. Though we have a lot of the species from this area I cannot confidently state that we have the full distribution of species for this area. Since I believe our distribution is not a complete one I cannot make any assertions on how the species compositions has changed over time. It is true, however, that there has been a lack of Spongia species at Gulf Specimen despite their various collection sites, and frequency of collection trips. I also haven’t seen Aplysina cauliformis in this area, nor at Gulf Specimen.

Of the 37 total species we found, 16 of these were not previously described in this area by either study. These species were also a mixture of Caribbean and temperate fauna. Many of these specimens were undescribed species, such as Clathria sp., Tethya sp., Suberites sp., and the two different Halichondria species. Other species that were not previously reported may simply be geographic variations or sister species, such as Haliclona cf. tubifera or Aaptos cf. pernucleata. It is interesting that we found so many species that were unreported by either study, considering that this study is a first step towards having a full and complete understanding of the distribution in this area.

There are several possible reasons these species may not have been on the list. One reason is that the species hasn’t been described, so it was absent in earlier studies. Another reason could be that a particular species wasn’t collected due to its close resemblance to another species. This could potentially be the case for species like Aplysina fulva where a close relative

Aplysina cauliformis was reported. It is possible that these two narrow-branching species could be mistaken for each other, especially if collections were made by trawling and so the specimens were bruised by the time they were observed, as this would cause the typical difference in surface color of healthy living specimens to go unnoticed. One other possibility is that the

29 species was named after the time of de Laubenfels’ and Little’s collection. One potential example of this from our study is Axinella pomponiae which was described in 1998 by Alvarez, van Soest and Rützler (Avarez, 1998), a few decades after de Laubenfels’ and Little’s work. Six of the additional species we found are well known in the Caribbean, one example being

Haliclona cuaҫaoensis.

One of the other potential reasons for our finding species that were not found in the previous studies is that these species may have recently colonized this area due to climate change. This is one of the reasons why it is so critical that further steps are taken to perform comprehensive collections so we can make these explicit comparisons. A lot of this confusion as to why we found additional species might be rectified by cross checking the species identified by de Laubenfels and Little by looking at their original specimens, some of which are deposited in the Yale Peabody Museum of Natural History.

Identification of marine sponges is a difficult task. Unlike many other animals, many sponges don’t have a specific body shape, color, or design (Rützler 1987). Often sponge species are grouped into growth form categories such as massive or branching, with hundreds of species falling under those descriptions (Rützler 1987). Color is also usually a poor indicator of sponge species since many species have a wide range of color variations and descriptions on color vary from person to person. What we usually rely on instead are the skeletal components such as spongin fibers and spicules. Sometimes the skeletal components alone are not sufficient to make a proper identification to the species level, so it’s necessary to have a variety of different tools to help with identification. The most helpful tools are intact specimens, field notes about the living sponges, and photos. Detailed notes in the field on sponge size, shape, colors, texture, toughness, or any other unique descriptions can make all the difference during identification. It’s important

30 to stay organized in the field and review your samples to make sure all the sample numbers match the descriptions and vice versa. Photographs are also a critical tool that can be extremely useful, with both close up photos of the surface and overall photos of the individual being important.

Identification literature for sponges is another difficult aspect of sponge identification.

Often papers will report different spicule measurements for the same species, and have vastly different descriptions of the color and spicule complement or species will be listed without details and notes from the identifier on the process and how sure they are of the species. Detailed notes on the identification process and any discrepancies amongst species, as demonstrated by de

Laubenfels 1953 and Little 1963, are extremely helpful for other researchers. Often I found myself torn between two species, or a species but with atypical coloring, only to find that Little had reported the same discrepancies. Recording these discrepancies also makes it possible for later researchers to differentiate newly recognized species, as was the case in this thesis with

Halichondria corrugata. Primary literature is another necessary tool for identification. The

Wulff lab has a collection of hundreds of papers ad books dating back to 1864, which allows for accurate identification of sponge species. Often I found myself having to go to the original description of a species in order to disentangle the multitude of different species identification possibilities. An added difficulty, however, is that these can often be in different languages, and lack spicule measurements if they date far enough back. In order to create a list of sources that were helpful for this study area I have created a separate bibliography of papers used for identification purposes.

Overall the critical elements needed in order to make confident identifications are the following: really good photos of the whole individual, and a well preserved specimen in order to

31 get not only the spicules but also any skeletal preparations you might need. Good resources for identification are also a necessity. Lastly, knowledge of different spicule types, and what differences to look for within a spicule type, along with hands on experience in the field with these organisms, can make all the difference when trying to distinguish between two closely related species.

Online resources are starting to become excellent starting grounds for identification.

Websites like the World Porifera Database often have downloadable pdfs of the original descriptions for species. Other websites like The South Florida Sponge Guide

(http://www.portol.org/guide/) is an online resource that includes photos illustrating the full range of phenotypic variation within a species, as well as spicules and skeleton preparations, but only for a limited selection of species. Hopefully adding more species to this guide will make proper species identification easier.

Despite the challenges sponge identification presents it is still necessary. Overall the fact that we found 16 species that weren’t previously recorded could be an indicator that the species distributions have shifted. Since there have been so few surveys in this area, this study is one of the few comparisons of species distributions for the Apalachee Bay. It’s also really important to realize that once we have a species name this opens up access to all the information where work has been done. Some of this information might include growth rates, regeneration rates, ecological symbioses, and also interactions.

II. Ecological Interactions II.1 Introduction

In this study, I also wanted to explore what kinds of interactions are occurring in this system. Sponges are key players in a variety of different ecological interactions in many different ecosystems. Sponges can occasionally be predators, as with the rare carnivorous sponges. These small sponges live in deep ocean habitats and use their chela spicules as fishing hooks, trapping small copepods and other crustaceans (Vacelet and Boury-Esnault 1995). More commonly sponges are a prey organism to a variety of different organisms. They can be prey to angelfish, trunkfish, starfish, and even Hawksbill sea turtles (Wulff 1994, 1995, 2005, 2006a; Meylan

1990; Anderes and Uchida 1994; Dam and Diez 1997). Sponges are also active participants in a myriad of different symbiotic associations (Wulff 2006a). One example of this is the mutually beneficial relationship observed in coral reefs where sponges glue the corals onto the reef while the coral provides substratum for the sponge (Wulff 2006a, 2012). Sponges have also been found to use zoanthids as a defense mechanism to protect themselves from predators (Wulff 2006a,

2012).

In this section I wanted to look at what kinds of interactions are occurring in this system.

I specifically wanted to explore the relationship between local starfish and sponges, and also remark on many of the other ecological interactions we observed.

Sponges often utilize chemical defenses to deter predators (Wulff 2006a). Sponge chemical defenses have been well studied in the Caribbean with different sponge predators

(Wulff 2006a). The Oreaster starfish in the Caribbean has been used extensively in feeding experiments to test which sponges are defended against the starfish (Wulff 1995, 2006a). The

Oreaster feeding experiments resulted in very clear patterns of acceptance and rejection for

33 different sponge species (Wulff 1995). I wanted to use similar methods to test the relationship between the local starfish Echinaster spinulosus and the sponges in Apalachee Bay. Are these patterns potentially based on sponge genus characteristics? Order characteristics? Knowing the species distribution also allows for a discussion on different ecological interactions seen in the field, and other potential interactions reported in the literature.

II.2 Methods Starfish Feeding Experiments

To determine which sponge species could be consumed by starfish I performed feeding trials using Echinaster spinulosus starfish with 17 different sponge species in 6 different orders.

The starfish were collected from St. Joseph Bay Florida, and sponges were collected from St.

Joseph Bay and the Gulf Specimen Marine Lab in Panacea FL.

Starfish were placed in individual tanks and given 3-6 different sponge species to consume. I then recorded observations of feeding throughout the trial period of 3-5 days. Trial periods varied, based on the condition of the sponges, starfish, and water quality. Starfish were given a minimum of 4 days between trials in order to encourage feeding. In one trial, starfish were also given a choice between a sponge and squid, and all starfish chose the sponge and ignored the squid. During observation periods, notes were recorded on which sponges the starfish had their central disk on. Feeding was determined based on starfish behavior and their presence on a sponge for more than 40 minutes. I could tell a starfish was feeding based on the appearance of the starfish since feeding can be indicated if the starfish’s arms anchor the starfish and then the central disk swells (Waddell and Pawlik 2000). The 40 minute time allotment was chosen to eliminate non-feeding movement. At times the central disc would be over a sponge but then 15 minutes later the starfish would move away. Whenever feeding did take place, as apparent by comparisons with control sponges, the starfish was recorded on that sponge for at least 40 minutes so that is the minimum time we chose. At the end of the trial period sponges were compared to control sponges to re-confirm feeding. Ambiguous trials, in which it was unclear if a starfish ate any part of the sponge, were decided if a starfish was on a sponge less

35 than 40min. The result designated “Not consumed” if a starfish wasn’t recorded touching the sponge and the sponge looked identical to the control after the trial period.

For a vast majority of the sponges tested feeding was obvious when tested sections were compared with controls. The tissue would often display a noticeable color loss, or the entirety of the tissue would be gone. Control sponges experienced tissue retreating, however the trial sponges were only considered a positive indicator of feeding if the tissue appeared dramatically different. I was certain that the starfish made a choice as well. When we turned off the air stones the starfish would often move quickly toward a particular sponge, passing over certain species until contacting one particular species. The starfish would then stay on the sponge for more than

40 min and when we compared the trial sponges to the controls at the end of the trial we would see clear indicators of tissue loss by a perfectly visible skeleton lacking color or tissue. If the starfish were merely feeding on surface organisms on the sponge it seems unlikely they would care which sponge species they fed on. Detritus can collect on the surface of the sponge in the field, however all our samples had clean surfaces.

II.3 Results

Table 2: Starfish Feeding Trials with Apalachee Bay Sponges

Sponge Species Consumed Not consumed Ambiguous Sponge Order Hadromerida Pseudospongosorites suberitoides 3 7 1 Pseudospongosorites suberitoides 0 1 0 Hadromerida red Cliona celata 6 2 0 Hadromerida Axinella polycapella 2 20 1 Halichondrida

Halichondrida Halichondria corrugata 15 5 5 Halichondrida Halichondria sp. Orange 9 0 4

Haplosclerida Haliclona curaҫaoensis 0 11 0

Dictyoceratida Dysidea sp. 6 14 6 Dendroceratida Igernella notabilis 4 0 0 Aplysina fulva 3 14 6 Verongida Ircinia sp. 7 3 4 Dictyoceratida Clathria prolifera 0 8 2 Poecilosclerida Lissodendoryx stigmata 4 1 4 Poecilosclerida Clathria sp. 0 11 0 Poecilosclerida Cinacyrella apion 0 4 0 Spirophorida Halichondria sp. Dark Green 0 7 1 Halichondrida Halichondria sp. Yellow 4 5 2 Halichondrida Table 2 Results: Haliclona curaҫaoensis, Cathria prolifera, Clathria sp. Cinachyrella alloclada, Dark green Halichondria sp. and yellow Halichondria sp. were not consumed in any of the trials. Igernella notabilis and Orange Halichondria were consumed in every trial and all the other sponges fell within a range between being eaten most of the time, and not being eaten most of the time.

Table 3: Starfish Feeding Spectrum with % of times consumed

II.4 Discussion

It’s initially obvious that there is an extreme amount of variation in the degree to which starfish consumed sponges between species. Most of the sponge species don’t fall into simple rejected or accepted categories like we see with the Oreaster (Wulff 1995). Instead we see this spectrum of consumption where some species like Igernella notabilis and Halichondria sp. orange were consumed in every trial. Other species like Haliclona cuaҫaoensis Cinachyrella alloclada and Clathria prolifera were rejected in every trial (Table 2 and 3). A majority of the sponge species fall into a range of consumption from being consumed in 9% of the trials to 80% of the trials (Table 3). I think the important thing here is that some species were outright rejected in every single trial, while other species were consumed occasionally, or a majority of the time. I don’t think from this study that we can describe any of the species where a majority were not consumed as potentially chemically defended as long as one or two were consumed.

We also noticed a lot of different ecological interactions occurring in the area we observed. A few studies have been done in past years documenting some of the interesting interactions in this area. One particular interaction that has been well studied is the relationship between hermit crabs and the hermit crab sponge Pseudospongosorites suberitoides (Sanford,

1994). Certain species of hermit crabs demonstrate this symbiosis where the sponge encrusts the gastropod shell occupied by the hermit crab and grows to encompass the shell. As the sponge grows the hermit crab switches to occupying one of the osculum, providing a continuously growing home, though they have been demonstrated to switch to clean shells sometimes

(Sanford 1994; Arndt 1933).

Other symbiotic associations have been noted with crustaceans. Different sponge species have been found to grow on a carapace or shell, covering the crustacean. The sponge receives

39 hard substratum for settlement and growth while the crustacean sometimes receives protection by camouflage, or even chemical defenses (Wulff 2006a).

One interesting interaction involves the sponge Halichondria (Halichondria) corrugata.

We commonly found this sponge at the Gulf Specimen tanks, which suggests its presence in deeper waters. While we did find it at St. Joseph Bay we never found it growing independently.

Instead we only found it attached to a local decorator crab, Macrocoeloma trispinosum. When I did feeding trials with Echinaster spinulosus in the area I noticed the starfish would attempt to feed on the sponge regardless of the presence of the decorator crab (Figure 3 without crab).

When the decorator crab was present the starfish was unable to feed on the sponge since the crab would pinch at the starfish and fend it off.

Figure 3: Starfish feeding on H. corrugata without the presence of a decorator crab.

Clathria sp., from both the feeding trials and the distribution study, was found encrusting on pen shells and over limpets on the pen shell. When we looked closer at the sponge we found a juvenile decorator crab that had incorporated the sponge onto its exoskeleton (Figure 3).

Figure 3: A juvenile decorator crab incorporating sponge. The sponge species is predicted to be Clathria sp. since it matches the surrounding sponge the crab was on.

Several of our species have also been reported in the Caribbean where a lot of work had been done on ecological interactions. Tedania ignis has been demonstrated as a master of chemical warfare, outcompeting sponges on mangrove roots (Wulff 2006a). Aplysina fulva and

Amphimedon compressa have been shown to increase each other’s growth rate when they are together (Wulff 2006a). Igernella notabilis has a nudibranch that may selectively feed on it

(Valdés, 2011) and was also used to decorate the shells of decorator crabs when given as a decoration choice (Personal observation).

Another interesting sponge species we found was Haliclona cuaҫaoensis which we found encrusting on pen shells. This has been the most frequently found sponge species in St. Joseph

Bay for many years, and it has not been identified until now. Once we identified the name we

41 found that this species is well studied in Belize. This species has been demonstrated to be an early successional species on mangrove roots in Belize, however it is a poor competitor (Wulff,

2009). Information on this species’ growth rate, and regeneration rates have also been studied

(Wulff 2009). None of this work has been repeated in this area, which allows for an interesting comparison to see if any of these rates or habits change in this remarkably different habitat. For example is this sponge a successional species in St. Joseph Bay as well? Are the growth rates and regeneration rates the same despite living in a seagrass habitat in waters with a remarkably different temperature than Belize? All the information we were able to accumulate for this species demonstrates the power of having an accurate species name. Knowing the species name allows us to access the literature and see what work has been done on this sponge in other habitats and other geographic localities.

Overall we discovered that the local starfish species exhibit a spectrum of consumption of sponge species, in which there is a range between species that were fed on in 100% of the trials and 0% of the trials. We also noticed interactions between crustaceans of two very different groups (i.e., hermit crabs and decorator crabs) and sponges, allowing the sponges to become motile. Knowing the names of sponges that had not previously been identified has made possible the opportunity for studies to reveal new and interesting ecological interactions.

CONCLUSIONS AND DISCUSSION:

This study has laid the ground work for continued study of the distribution of sponge species in Apalachee Bay, as well as many of their ecological interactions. We successfully identified to species, or at least to genus, many dozens of specimens that were collected at several sites that represent the variety of habitats in Apalachee Bay. We found several species that have not been previously reported in the northern Gulf of Mexico. Our finding them could be a result of their having recently colonized this area due to range shifts resulting from climate change. Alternatively the lack of earlier records of these species could be due to other factors relating to the difficulty and complex nature of sponge identification. When looking at the interactions in this system we found that the starfish respond to sponges as prey in a spectrum of consumption, and we also began studies of interactions between crustaceans (both hermit crabs and decorator crabs) and sponges. Our understanding of the species’ names has paved the way for additional studies on ecological interactions of sponges in the northern Gulf of Mexico.

Even though proper identification is difficult it is critical that we persevere until we have accurate identification, because sponges exhibit extremely high species diversity. Different sponge species can play entirely different roles in their environment so it’s important that we have correct names attached to our studies on ecological interactions. This way our understanding of this system is not distorted, impeding further progress. It is essential that species are identified accurately if we are to understand distribution and diversity patterns as well as all the complicated and interesting ecological interactions within a system.

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