Sponge Notes

Leucetta - Dani

Leucetta sp with mottled triplefin Photo: Danica Stent

Quick question – are sponges plants or animals?

Sponges belong to the Order Porifera, being shot through with many pores. They use these pores (ostia) to pump water and foods into the body of the sponge, and pump water and wastes out of the body through one large opening, called the osculum. Sponges are sessile, which means they become attached to substrate, usually rocks or sometimes shells, and stay in the one place for their lives – which can be as short as one season, or several decades. Parts of sponges can break off or be broken away and set up at attachment elsewhere. They can be flat against a rock face, encrusting like coralline algae. 

They are animals, not plants. Sponges were believed to be solidified sea foam in the sixteenth century and until 1765 they were thought to be plants. They are classified as animals, however, they lack the brain, the central nervous system, digestive system and a cardiovascular system of higher animals. Indeed, they are amongst the simplest of multicellular animals. They existed way back into fossil records and have been very successful in evolving into a highly diverse order of animals, having both fresh and saltwater forms, occupying habitats from very shallow water to the oceanic deeps. They cover a wide range of colours, shapes and sizes.

Structure of Sponges

While some sponges can be quite distinctive they generally present a challenge to those who would wish to classify and give names to them. Indeed, much of the definitive taxonomical work has relied on microscopic examination of silicon spicules in the bodies of specimens. They can be easily confused with sea squirts which are ascidians – way further up the evolutionary tree in Order Chordata.

Sponges show a range of complexity. The most basic are ‘asconoid’ – the simplest in form, being vase like (as shown in the diagram above), generally very small and exist in shallow waters. ‘Syconoid’ sponges are more complex and folded, and ‘leuconoid are the most complex, having more folding and more distinct structure. These are the most common and largest of the sponges – up to several metres in height or width.

Sponge Slice 2

13_05_05_Tethya Taputeranga_MPF9

Tethya sp Golf Ball sponge Photo: M Francis 

Getting back to the manner in which sponges feed, the tiny external ostia lead internally to a system of canals and eventually out to one or more larger holes, called oscula. Within the canals, chambers are lined with specialized cells called choanocytes, or collar cells. The collar cells have a sticky, funnel shaped collar and a hair-like whip, called a flagellum. The collar cells serve two purposes. First, they beat their flagella back and forth to force water through the sponge. The water brings in nutrients and oxygen, while carrying out wastes and carbon dioxide. Second, the sticky collars of the collar cells pick up tiny bits of food brought in with the water. Another type of cell, called an amebocyte, takes the food to other cells within the sponge. Sponges have the ability to filter out up to 90% of the bacteria which pass into the canals. They can pump up to 5 times their own volume through the system every minute! This can have a major effect on the local marine environment, cleaning out foods that might well go to other animals, as well as mopping up some polluting organisms.

Sponges of the Wellington South Coast

Porifera divide into three classes. Most sponges fit within Class Demospongia, with internal skeletons mostly of silica spicules, although some may contain spongin and collagen fibres. Some can live for up to a hundred years. Class Calcarea contain sponges with a calcareous skeleton, and most are very small, and relatively short-lived. The third Class Hexactinellida, contains the glass sponges, which mostly live in the oceanic deeps. There are some species of this class occurring in shallower water off the NZ north east coast and in Fiordland.

There are probably well over 1000 species of sponges in New Zealand waters, of which less than half have been fully described and classified. Some marine reserves, notably  Parininihi (North Taranaki), Te Angiangi (Southern Hawkes Bay) and Horoirangi (Nelson Boulder Bank) have well established ‘sponge gardens’ on relatively flat or undulating rocky or boulder substrate, However, sponges are also found in cracks and crevices, caves and overhangs – places where their lack of dependence on photo synthesis is not a disadvantage. Most of the NZ sponges are considered to be endemic.

 Taputeranga Marine Reserve falls into a region where northern and southern species overlap, providing considerable species richness, in sponges no less than for macroalgae. There is considerable variability in the sponge assemblages from site to site. Although the waters of the marine reserve are low in suspended organic material (which is considered a limiting factor for mussel growth and survival on the open coast), sponges appear to have an ability to filter to an extraordinary small particle size. Sponge assemblages at the Sirens and at the Yung Pen reef attest to the high density of sponges even in a relatively low organic nutrient environment. It is possibly the lack of filter feeding competition (e.g. from some molluscs) that opens spaces for the more efficient feeding sponges.

 13_05_05_Clathrina white_MPF10

Clathrina sp sponge in the Snorkel Trail area

13_05_05_Ancorina_MPF14

 Ancorina sp. at Yung Pen wreck. Both photos: M Francis

Taputeranga Marine Reserve falls into a region where northern and southern species overlap, providing considerable species richness, in sponges no less than for macroalgae. There is considerable variability in the sponge assemblages from site to site. Although the waters of the marine reserve are low in suspended organic material (which is considered a limiting factor for mussel growth and survival on the open coast), sponges appear to have an ability to filter to an extraordinary small particle size. Sponge assemblages at the Sirens and at the Yung Pen reef attest to the high density of sponges even in a relatively low organic nutrient environment. It is possibly the lack of filter feeding competition (e.g. from some molluscs) that opens spaces for the more efficient feeding sponges.

Mycale hentscheli  11_02_06_Lecosolinia echinata MPF1

Mycale hentscheli, Marlb. Sounds             Leucosolenia echinata
Photo Mike Page                                               Photo: Malcolm Francis

Uses of and Benefits from Sponges – Why are they Important?

  • Sponges can modify substrates. Some sponges actively bore into rocks and mollusc shells. Others may glue elements of the substrate together.
  • Sponges have a major impact in the water column, by filtering sea water, removing organic particles, as well as nitrogen, oxygen, calcium and silicon. Foods include phytoplankton, bacteria and even larger viral particles.
  • Sponges provide micro-habitats for bacteria, fish, crabs and even other sponges. Some crabs will ‘adopt’ pieces of sponge and attach them to their exoskeleton as camouflage.
  • Sponges have been found to be sources of bioactive compounds such as anti-tumour agents, and chemicals that are of promise in treating arthritis, heart disease and AIDS. Mycale hentscheli, pictured above, has been found to contain a substance called peloruside A, which kills cancer cells. NIWA has attempted to translocate and farm this sponge, in order to ‘bulk it up’ as a source of the chemical, although with mixed success.
  • Sponges also affect the flow of sea water across substrates, altering habitats on a seasonal or more permanent basis.

The natural sponges we use in our baths are actually sponge skeletons. Bath sponges consist of a highly porous network of fibres made from a collagen protein called spongin. The skeletons are obtained by cutting the growing sponges and soaking the cut portions in water until the flesh rots away. They then have the elastic skeleton decalcified, rinsed and bleached. Sea sponges are also used in the medical field during surgical procedures because of their excellent absorbent qualities.  In recent years New Zealand scientists have investigated the possibility of farming a native species of bath sponge, Spongia manipulatus, for commercial production. Sources elsewhere have been over-exploited.

Raspalia MF    13_05_05_LeucettaTaputeranga_MPF13

Raspalia sp. finger sponge from           Leucetta sp, Taputeranga MR Photo: M Francis
Kapiti MR Photo: M Francis

References used in this article:

Chapter 13 ‘Sponges of the Wellington South Coast’ J Berman, A Perea Blazquez, M Kelly and J Bell, in ‘The Taputeranga Marine Reserve’, second edition, edited by J Gardner and J Bell, 2008

 ‘Open Access Spatial Variability of Sponge Assemblages on the Wellington South Coast, New Zealand’, Jade Berman* and James J. Bell Centre for Marine Environmental and Economic Research, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand, The Open Marine Biology Journal, 2010, 4, 12-25

Jonathan Bird Oceanic Research Group, www.oceanicresearch.org

Buzzle: http://www.buzzle.com/articles/sponge-facts.html