Interocean patterns in shallow water sponge assemblage structure and function

Abstract

Sponges are a major component of benthic ecosystems across the world and fulfil a number of important functional roles. However, despite their importance, there have been few attempts to compare sponge assemblage structure and ecological functions across large spatial scales. In this review, we examine commonalities and differences between shallow water (<100 m) sponges at bioregional (15 bioregions) and macroregional (tropical, Mediterranean, temperate, and polar) scales, to provide a more comprehensive understanding of sponge ecology. Patterns of sponge abundance (based on density and area occupied) were highly variable, with an average benthic cover between ~1 and 30%. Sponges were generally found to occupy more space (percentage cover) in the Mediterranean and polar macroregions, compared to temperate and tropical macroregions, although sponge densities (sponges m–2) were highest in temperate bioregions. Mean species richness standardised by sampling area was similar across all bioregions, except for a few locations that supported very high small‐scale biodiversity concentrations. Encrusting growth forms were generally the dominant sponge morphology, with the exception of the Tropical West Atlantic, where upright forms dominated. Annelids and Arthropods were the most commonly reported macrofauna associated with sponges across bioregions. With respect to reproduction, there were no patterns in gametic development (hermaphroditism versus gonochorism), although temperate, tropical, and polar macroregions had an increasingly higher percentage of viviparous species, respectively, with viviparity being the sole gamete development mechanism reported for polar sponges to date. Seasonal reproductive timing was the most common in all bioregions, but continuous timing was more common in the Mediterranean and tropical bioregions compared to polar and temperate bioregions. We found little variation across bioregions in larval size, and the dominant larval type across the globe was parenchymella. No pattens among bioregions were found in the limited information available for standardised respiration and pumping rates. Many organisms were found to predate sponges, with the abundance of sponge predators being higher in tropical systems. While there is some evidence to support a higher overall proportion of phototrophic species in the Tropical Austalian bioregion compared to the Western Atlantic, both also have large numbers of heterotrophic species. Sponges are important spatial competitors across all bioregions, most commonly being reported to interact with anthozoans and algae. Even though the available information was limited for many bioregions, our analyses demonstrate some differences in sponge traits and functions among bioregions, and among macroregions. However, we also identified similarities in sponge assemblage structure and function at global scales, likely reflecting a combination of regional‐ and local‐scale biological and physical processes affecting sponge assemblages, along with common ancestry. Fi...

Sponge–Microbe Interactions on Coral Reefs: Multiple Evolutionary Solutions to a Complex Environment

“…These species represent 25% of the sponge community on reefs in the Bocas del Toro (BDT) archipelago of Panama (a region highly influenced by allochthonous inputs from land; Aronson et al, 2014;Easson et al, 2015) and 5.6% of the entire sponge community in this ocean basin (Figure 3B; Loh and Pawlik, 2014). In addition, with over 30% of dominant Caribbean sponges hosting abundant photosymbiont communities (Wilkinson, 1987;Rützler, 1990;Thacker, 2007, 2008;Thacker et al, 2007;Bell et al, 2020) and evidence that many of these symbionts fix inorganic sources of carbon and translocate fixed carbon to their host (Freeman et al, 2013), it is likely that more Caribbean sponges are heavily reliant on their photosymbionts. Finally, as the GBR and Caribbean Sea are now recognized to have comparable levels of POM, DOM, and inorganic nutrients (de Goeij et al, 2017), interocean differences in sponge biomass, morphologies, and reliance on photosymbionts are likely shaped by factors beyond just perceived nutrient limitation.…”

“…Although pioneering work by Wilkinson (1987) and Wilkinson and Cheshire (1990) attributed patterns of sponge biomass and nutrition to inshore-offshore resource gradients, other factors may certainly contribute to these patterns. For instance, competitive interactions between sponges and anthozoans are common (Bell et al, 2020) and may be influencing sponge distribution and evolution. On the GBR, sponges are common on inner sites where corals are rare (Done, 1982;, but sponges are a minor component (6.8% of bottom cover) of the benthic community on offshore sites compared to hard and soft corals (31 and 12.4% cover, respectively) (Reichelt et al, 1986;Wismer et al, 2009).…”

“…Sponges were reported to vary in characteristics such as the complexity of their aquiferous system, tissue density, pumping rate, abundance of microbial symbionts, morphology, and exploitation of different nutrient sources (Reiswig, 1971(Reiswig, , 1974Vacelet and Donadey, 1977;Reiswig, 1981;Wilkinson, 1983). More contemporary work has expanded this story by identifying substantial interspecific variation in growth rates, reproductive effort, community composition and diversity of microbial symbionts, reliance on different heterotrophic nutrient pools, microbial symbiont nutrient transformations, metabolic plasticity, and chemical defense production (Loh and Pawlik, 2014;Wulff, 2017;McMurray et al, 2018;Pawlik et al, 2018;Pita et al, 2018;Zhang et al, 2019;Bell et al, 2020). Despite this wealth of research, both classic and contemporary papers frequently group species based on one characteristic (i.e., sponges either host productive symbionts or do not, have either high or low microbial abundance, or are either chemically defended or undefended); this trend toward binary categorizations has led to broad generalizations about sponge ecology and evolution (Wilkinson and Cheshire, 1990;Loh and Pawlik, 2014;McMurray et al, 2018).…”

Variation in autotrophic and heterotrophic sponge abundance in a shallow water seagrass system

“…Wilkinson 1987b;Steindler et al 2002) and temperate waters (Roberts et al 1999; Lemloh et al 2009), although the true extent of these relationships is poorly known (Usher 2008). In addition, there are only a few studies that have measured gross primary production to respiration (P:R) ratios to estimate the nutritional mode of sponge holobionts (see review by Bell et al 2020). Most previous studies of sponge-photosymbiont interactions have been focused on the existence of photosynthetic symbionts in sponges by measuring pigment concentrations -particularly chlorophyll-a (eg.…”

Zootaxa 20 years: Phylum Porifera

“…They are major components of benthic communities although their patterns of abundance can be highly variable, ranging from highly dense and extensive populations in some communities to sparse and rare in others (e.g. Bell et al 2020).…”