Happy relationships between marine sponges and sediments – a review and some observations from Australia

Abstract

Being sessile filter feeders, sponges may be disadvantaged by sediments in many ways, e.g. through clogging and burial. However, in order to correctly recognize negative effects of sediments in the field, natural relationships of sponge taxa adapted to a life with sediments need to be understood. The present publication reviews available literature and provides observations on natural and beneficial interactions of sponges with sediments, distinguishing several strategies: (1) Saving energy through sediment incorporation, reducing or replacing spicule production commonly occurs in keratose, verongimorph, tethyid and poecilosclerid sponges, which often received scientific names referring to sediments. (2) Forming sediment crusts externally or embedded in surface tissues reinforces outer layers, provides shade, and for external crusts camouflage and shelter from spongivory and desiccation. External crusts often occur in the tethyids and axinellids, while surface armour is most common in keratose sponges. (3) Anchoring in soft sediments provides a selective advantage for space colonization. This is mainly achieved in the hexactinellid, polymastiid and spirophorine sponges by using spicules (predominantly in deeper water), commonly in endopsammic sponges by rootlets, basal agglutination and basal incorporation of particles, and in various groups by attachment to buried materials (shallow water). (4) Living at least partially embedded in sediments (psammobiosis) appears to be best developed inOceanapiaspp. and bioeroding sponges, generates shelter from various external conditions and reduces the risk of spongivory. Typical morphological characters of sediment-adapted sponges are thus sediment skeletons and surface crusts (reinforcement), stalks and fistules (elevation above sediments), spicule tufts and root-systems (anchoring).

Spongivory by Fishes on Southwestern Atlantic Coral Reefs: No Evidence of Top-Down Control on Sponge Assemblages

“…In fact, we observed contact between D. anchorata and M. alcicornis and M. cavernosa in the present study, potentially allowing D. anchorata to avoid sediment accumulation (McLean and Yoshioka, 2008;Schönberg, 2016). Sediment-incorporation by the sponge can also reduce the necessity of spicule formation (i.e., spiculogenesis) saving energy that can be allocated to other biological demands such as growth, reproduction and competition (Schönberg, 2016). In addition, D. achorata morphology can also occur as a branching form, avoiding sediment accumulation, with relatively high growth rates, that may accelerate the recovery of predation and competition damages (Wulff, 2006).…”

“…Second, it can establish interactions with several organisms, mainly growing over other organisms with erect growth such the octocoral Carijoa riisei (Calcinai et al, 2004) and the branching coral Millepora alcicornis (McLean and Yoshioka, 2008). In fact, we observed contact between D. anchorata and M. alcicornis and M. cavernosa in the present study, potentially allowing D. anchorata to avoid sediment accumulation (McLean and Yoshioka, 2008;Schönberg, 2016). Sediment-incorporation by the sponge can also reduce the necessity of spicule formation (i.e., spiculogenesis) saving energy that can be allocated to other biological demands such as growth, reproduction and competition (Schönberg, 2016).…”

“…The most abundant sponge species in TSB, D. anchorata, presented two important characteristics. First, it is able to incorporate free sediment particles that may give structural reinforcement to their body (Hajdu et al, 2011;Schönberg, 2016). Second, it can establish interactions with several organisms, mainly growing over other organisms with erect growth such the octocoral Carijoa riisei (Calcinai et al, 2004) and the branching coral Millepora alcicornis (McLean and Yoshioka, 2008).…”

Classical and new bioerosion trace fossils in Cretaceous belemnite guards characterised via micro-CT

“…Inhalant structures often display the exact opposite morphological principle: the diameters of the inhalant pores (ostia) can be significantly reduced by tissue features that subdivide the openings or by replacing a single larger opening with several smaller ones (occasionally referred to as cribriform papillae or as pore sieves; see Carter, 1879 andRützler, 2002). The limited diameter of these inhalant pores will reduce the incurrent speed and regulate the maximum particle size that can enter the sponge's canal system, thus providing an efficient filter that helps avoiding the intake of sediment grains and other unwanted particles that can clog the sponge's circulation system and compromise vital functions (Yahel et al, 2006;Bell et al, 2015;Schönberg, 2016). As far as the bioeroding sponges are concerned, this applies to all species of the genera Cliona, Cliothosa, Spheciospongia, and Siphonodictyon (see e.g.…”

“…In this case, the grated nature of the apertures could have been of an advantage not only for inhalant pores but also for the larger exhalent ones. As far as extant excavating sponges are concerned, the occurrence of pores exhaling into the sediment is known, for instance, for psammobiontic forms (Schönberg, 2016). However, the morphology of E. colaria isp.…”