The three grades of metazoan animals Animalia KINGDOM: Mesozoa GRADE: Parazoa Eumetazoa PHYLA: Placozoa Porifera Mesozoa All other animal phyla

Phylum Porifera the sponges 1st phyla we will talk about and what we will cover in the lab today is… the sponges

Phylum Porifera Branch Parazoa – “beside + animal” Sponges are at the cellular level of organization and have no tissues or organs. Sponges are assemblages of cells embedded in a protein matrix and supported by a skeleton of needle-like structures. For a long time, taxonomists did not think sponges were animals  branch parazoa But they are animals! Why an animal? Mulitcellular and Sessile but have moving cells, sperm, larvae, etc… Cellular organiztion

External Morphology Size: range mm to >2m Color: lots Shape: encrusting, boring, free-standing, branching, lobed…

General Body Plan osculum spongocoel ostia choanocytes water (plural=oscula) spongocoel Despite all this diversity in size, shape and color, most sponges have the same general body plan where They have holes where water comes in, canals where the water passes thru them, and a hole where the water comes out ostia (singular=ostium) choanocytes water

General Body Plan Choanocytes: “collar cells” diagnostic of phylum Porifera consist of a long flagellum surrounded by a “collar” of microvilli functions: obtaining food creating water currents reproduction

General Body Plan osculum spongocoel ostia choanocytes water (plural=oscula) spongocoel Despite all this diversity in size, shape and color, most sponges have the same general body plan where They have holes where water comes in, canals where the water passes thru them, and a hole where the water comes out ostia (singular=ostium) choanocytes water

3 Body Types Based on the complexity of the water canals: Asconoid Syconoid Leuconoid Although in other phyla we learn classes, for porifiera we will learn 3 main body types Increasing size Increasing Surface Area :Volume

Asconoid Body Type osculum spongocoel ostia water (plural=oscula) spongocoel Despite all this diversity in size, shape and color, most sponges have the same general body plan where They have holes where water comes in, canals where the water passes thru them, and a hole where the water comes out ostia (singular=ostium) water Choanocytes line the spongocoel (the black shaded area)

Syconoid Body Type osculum ostia incurrent canals radial canals (plural=oscula) ostia (singular=ostium) Water flow incurrent canals radial canals spongocoel choanocytes line the radial canals (the black shaded area)

Syconoid Body Type prosopyle: radial canal: apopyle: opening from incurrent canal to radial canal Water flow radial canal: lined with choanocytes apopyle: opening from radial canal to spongocoel

Leuconoid Body Type oscula flagellated chambers spongocoel ostia Water flow spongocoel ostia Choanocytes line the flagellated chambers (the black shaded area)

Leuconoid Body Type prosopyle: opening form incurrent canals to flagellated chambers ostia incurrent canal apopyle: opening form flagellated chambers to spongocoel Water flow

3 Body Types Based on the complexity of the water canals: Asconoid Syconoid Leuconoid Although in other phyla we learn classes, for porifiera we will learn 3 main body types Increasing size Increasing Surface Area :Volume

SA = l2 X 6 V = l3

The large SA:V of leuconoid sponges More space for choanocytes More water flow Larger size Water flow

Microscopic Morphology archaeocyte (amoebocyte) porocyte choanocyte pinacocyte mesohyl spicules

Skeletal Elements Mesohyl proteinaceous matrix that contains skeletal material and certain cell types equivalent to the connective tissue in other organisms made of collagen and spongin

Skeletal Elements Spicules made of calcium carbonate or silica often used in taxonomic identification

Cell Types Choanocytes diagnostic of phylum Porifera consist of a long flagellum surrounded by a “collar” of microvilli functions: obtaining food creating water currents reproduction

Cell Types Archaeocytes also called “amoebocytes” found throughout mesohyl totipotent  can differentiate into any other type of cell functions: digestion through phagocytosis make spicules reproduction

Cell Types Pinacocytes line the exterior surface of the sponge functions: some can regulate water flow by moving (open/close ostia) outside of sponge inside of sponge

Cell Types Porocytes found in asconoid sponges form tubes in the body wall where water can pass through functions: allow water flow outside of sponge inside of sponge

Physiology Feeding Digestion Gas exchange Sessile filter-feeders Digestion Intracellular Gas exchange Simple diffusion Excretion (nitrogenous waste removal) **THE CARNIVOROUS EXCEPTION** Sponges of a particular family (Cladorhizidae) are actually carnivorous! They capture small crustaceans with their velcro-like spicules. Cells then migrate around the helpless prey and digestion takes place extracellularly

Physiology Reproduction 1. Asexual fragmentation budding regeneration gemmules

Physiology Gemmules: in freshwater sponges only resistant mass of archaeocytes that are produced in unfavorable conditions when the environment is favorable, they will develop into sponges                                                  

Physiology Reproduction 2. Sexual usually monoecious (a single individual produces both male and female gametes; both sexes are within one individual) sperm are released into the water and eggs are retained within the sponge motile larvae are produced                                                  

Some sponge larvae crawl along the bottom, whereas others are free swimming. Haliclona broods free-swimming parenchymella larvae that are assumed to be sexually produced These larvae are uniformly ciliated and possess directional swimming while constantly rotating along their longitudinal axis Larvae are released in the early summer (may-june) and over the course of several days, a small piece of ripe sponge (~5cm2) can release an average of 30 larvae to a maximum of over 100 larvae Under laboratory conditions, they swim for approx. 2-4 days prior to settlement and after which they rapidly metamorphose into small-sponges After release, larvae often aggregate at the water surface, swimming in tight circles around each other...

B. Some free-swimming larvae are capable of fusing with others!    These chimeric larvae continue to swim normally and are capable of successful metamorphosis into a juvenile sponge. fig A: a larval fusion approx. 20min after initial fusion fig B: the same larval fusion this time approx. 60 min after intial fusion These chimeric larvae are approximately double the size of single larvae, and upon metamorphosis, chimeric tissue is noticeably denser and covers a larger area than non-chimeric tissue (pers obs).

Larvae eventually settle and metamorphose into adults Haliclona broods free-swimming parenchymella larvae that are assumed to be sexually produced These larvae are uniformly ciliated and possess directional swimming while constantly rotating along their longitudinal axis Larvae are released in the early summer (may-june) and over the course of several days, a small piece of ripe sponge (~5cm2) can release an average of 30 larvae to a maximum of over 100 larvae Under laboratory conditions, they swim for approx. 2-4 days prior to settlement and after which they rapidly metamorphose into small-sponges After release, larvae often aggregate at the water surface, swimming in tight circles around each other...

Ecology most sponges are marine (~5000 species) but there are ~150 freshwater sponge species Sponges are found at all depths but certain species are restricted to particular depths due to how their spicules are formed There are few sponge predators because they usually contain distasteful toxins Some predators (e.g. sea slugs) sequester these sponge toxins which in turn deters their own predators -Depending on what spicules are made of, they are found at depths where the substance is not soluble. Eg. Calcium carbonate ones are in shallow water, silica ones are deeper -predators: eg.sea turtles, sea slugs -usually brightly colored to deter predators Sea slugs that eat them are also usuall brightly colored advertising their own distastefulness

Ecology Symbiosis – Types of symbiotic relationships: the living together of 2 different species in an intimate relationship Types of symbiotic relationships: Mutualism= both partners benefit Commensalism= 1 partner benefits, 1 partner is unaffected Parasitism= 1 partner benefits, 1 partner is harmed There are examples of all 3 of these types of symbiotic relationships occurring in Sponges -Depending on what spicules are made of, they are found at depths where the substance is not soluble. Eg. Calcium carbonate ones are in shallow water, silica ones are deeper -predators: eg.sea turtles, sea slugs -usually brightly colored to deter predators

Ecology Mutualism – certain ‘endosymbiotic’ bacteria and algae living within the sponge provide additional food for the sponge while the sponge provides a place for the bacteria and algae to grow -benefit for crab Benefit for sponge some crabs will attach a piece of sponge to their body to use as camouflage and to deter predators while the sponge gets to move around

Ecology Commensalism – many different species live within sponges and receive food and shelter benefits but do nothing for the sponge e.g. 15cm² piece of sponge in California was found to house 100 different species of plants + animals e.g.Venus’s Flower basket a pair of shrimp live their entire lives within 1 sponge -Depending on what spicules are made of, they are found at depths where the substance is not soluble. Eg. Calcium carbonate ones are in shallow water, silica ones are deeper -predators: eg.sea turtles, sea slugs -usually brightly colored to deter predators

Ecology Parasitism – boring sponges are parasites on certain corals because they bore into the calcium carbonate base of the coral for protection and kill part of the coral in the process -secrete a substance to dissolve the Caco3 by the archaeocytes nd bore into the coral -they then excrete the bits of shell through their oscula

FSU Research on Sponges: Dr. Janie Wulff wulff@bio.fsu.edu Smithsonian Institution field station at Carrie Bow Cay

The sponge communities of reefs and mangrove islands are very different. What factors are responsible for this difference? 1. Abiotic factors: Light, turbidity, nutrients, substrate, physical disturbance… 2. Biotic factors: competition, predation, parasitism…

The sponge communities of reefs and mangrove islands are very different. What factors are responsible for this difference? 1. Abiotic factors: Light, turbidity, nutrients, substrate, physical disturbance… 2. Biotic factors: competition, predation, parasitism… Determining which of these is more important is difficult because reefs and mangroves differ in abiotic and biotic factors.

What factors determine the diversity of sponges in a habitat?

What factors determine the diversity of sponges in a habitat? Twin Cays Pelican Cay -Species composition: there are 167 species in both habitats combined, but 78 % of the species are found in only one of the two locations.

What factors determine the diversity of sponges in a habitat? Twin Cays Sponges grow on mangrove roots Sponge diversity is typical of mangrove stands throughout the Western Atlantic

What factors determine the diversity of sponges in a habitat? Pelican Cay Sponges grow on mangrove roots Sponge diversity is typical of shallow coral reefs

Why do these two similar habitats have such different sponge communities ? Transplant experiments: small pieces of sponge from each habitat were attached to mangrove roots in the native and non native habitat Twin Cay sponges Pelican Cay sponges

Transplant experiments: 1. Caging experiments: the role of predation Why do these two similar habitats have such different sponge communities ? Transplant experiments: 1. Caging experiments: the role of predation Twin Cay sponges transplanted in Pelican Cay uncaged TC sponge caged TC sponge

Competition Results:

Competition Results: Sponge predators in Pelican Cay: Gray angelfish Redband parrotfish These spongivores are also present on reefs.

Transplant experiments: 1. Caging experiments: the role of predation Why do these two similar habitats have such different sponge communities ? Transplant experiments: 1. Caging experiments: the role of predation 2. Competitor free space: the role of competition TC sponge Pelican Cay sponges transplanted in Twin Cays uncaged PC sponge sponge attached to pvc

Competition Results: Sponges in competitor free space have higher survival Wulff, in press

Competition Results: Sponges in competitor free space tend to grow more Wulff, in press

Competition Results: Pelican Cay Twin Cays There is a positive relationship between growth and survival in Twin Cays, but not in Pelican Cay Wulff, in press

The sponge communities of reefs and mangrove islands are very different. What factors are responsible for this difference? Dr. Wulff’s research suggests that biotic factors (predation and competition) are important : Competition plays a more important role in determining sponge diversity in mangrove habitats. Predation plays a more important role in determining sponge diversity in coral reef habitats.

The sponge communities of reefs and mangrove islands are very different. What factors are responsible for this difference? Dr. Wulff’s research also suggests that there maybe a trade-off between competitive ability and predator defense: Species found on reefs ? Defensive ability Species found in mangroves ? Competitive ability