Filtration Rates and Scaling in Demosponges
Demosponges are modular filter-feeding organisms that are made up of aquiferous units or modules with one osculum per module. Such modules may grow to reach a maximal size. Various demosponge species show a high degree of morphological complexity, which makes it difficult to classify and scale them...
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MDPI AG
2022-05-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/10/5/643 |
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| author | Hans Ulrik Riisgård Poul S. Larsen |
| author_facet | Hans Ulrik Riisgård Poul S. Larsen |
| author_sort | Hans Ulrik Riisgård |
| collection | DOAJ |
| description | Demosponges are modular filter-feeding organisms that are made up of aquiferous units or modules with one osculum per module. Such modules may grow to reach a maximal size. Various demosponge species show a high degree of morphological complexity, which makes it difficult to classify and scale them regarding filtration rate versus sponge size. In this regard, we distinguish between: (i) small single-osculum sponges consisting of one aquiferous module, which includes very small explants and larger explants; (ii) multi-oscula sponges consisting of many modules, each with a separate osculum leading to the ambient; and (iii) large single-osculum sponges composed of many aquiferous modules, each with an exhalant opening (true osculum) leading into a common large spongocoel (atrium), which opens to the ambient via a static pseudo-osculum. We found the theoretical scaling relation between the filtration rate (<i>F</i>) versus volume (<i>V</i>) for (i) a single-osculum demosponge to be <i>F</i> = <i>a</i><sub>3</sub><i>V</i><sup>2/3,</sup> and hence the volume-specific filtration rate to scale as <i>F</i>/<i>V</i> ≈ <i>V</i><sup>−1/3</sup>. This relation is partly supported by experimental data for explants of <i>Halichondria panicea</i>, showing <i>F/V</i> = 2.66<i>V</i><sup>−0.41</sup>. However, for multi-oscula sponges, many of their modules may have reached their maximal size and hence their maximal filtration rate, which would imply the scaling <i>F/V</i> ≈ constant. A similar scaling would be expected for large pseudo-osculum sponges, provided their volume was taken to be the structural tissue volume that holds the pumping units, and not the total volume that includes the large atrium volume of water. This may explain the hitherto confusing picture that has emerged from the power-law correlation (<i>F/V</i> = <i>aV</i><sup>b</sup>) of many various types of demosponges that show a range of negative <i>b</i>-exponents. The observed sharp decline in the volume-specific filtration rate of demosponges from their very small to larger sizes is discussed. |
| first_indexed | 2024-03-10T03:37:58Z |
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| id | doaj.art-c4e8f5e4834c4ff2b50ca4143b573777 |
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| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T03:37:58Z |
| publishDate | 2022-05-01 |
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| spelling | doaj.art-c4e8f5e4834c4ff2b50ca4143b5737772023-11-23T11:39:43ZengMDPI AGJournal of Marine Science and Engineering2077-13122022-05-0110564310.3390/jmse10050643Filtration Rates and Scaling in DemospongesHans Ulrik Riisgård0Poul S. Larsen1Marine Biological Research Centre, University of Southern Denmark, 5300 Kerteminde, DenmarkDepartment of Mechanical Engineering, Technical University of Denmark, 2800 Lyngby, DenmarkDemosponges are modular filter-feeding organisms that are made up of aquiferous units or modules with one osculum per module. Such modules may grow to reach a maximal size. Various demosponge species show a high degree of morphological complexity, which makes it difficult to classify and scale them regarding filtration rate versus sponge size. In this regard, we distinguish between: (i) small single-osculum sponges consisting of one aquiferous module, which includes very small explants and larger explants; (ii) multi-oscula sponges consisting of many modules, each with a separate osculum leading to the ambient; and (iii) large single-osculum sponges composed of many aquiferous modules, each with an exhalant opening (true osculum) leading into a common large spongocoel (atrium), which opens to the ambient via a static pseudo-osculum. We found the theoretical scaling relation between the filtration rate (<i>F</i>) versus volume (<i>V</i>) for (i) a single-osculum demosponge to be <i>F</i> = <i>a</i><sub>3</sub><i>V</i><sup>2/3,</sup> and hence the volume-specific filtration rate to scale as <i>F</i>/<i>V</i> ≈ <i>V</i><sup>−1/3</sup>. This relation is partly supported by experimental data for explants of <i>Halichondria panicea</i>, showing <i>F/V</i> = 2.66<i>V</i><sup>−0.41</sup>. However, for multi-oscula sponges, many of their modules may have reached their maximal size and hence their maximal filtration rate, which would imply the scaling <i>F/V</i> ≈ constant. A similar scaling would be expected for large pseudo-osculum sponges, provided their volume was taken to be the structural tissue volume that holds the pumping units, and not the total volume that includes the large atrium volume of water. This may explain the hitherto confusing picture that has emerged from the power-law correlation (<i>F/V</i> = <i>aV</i><sup>b</sup>) of many various types of demosponges that show a range of negative <i>b</i>-exponents. The observed sharp decline in the volume-specific filtration rate of demosponges from their very small to larger sizes is discussed.https://www.mdpi.com/2077-1312/10/5/643allometric scalingsponge modulechoanocyte densityspecific filtration rate |
| spellingShingle | Hans Ulrik Riisgård Poul S. Larsen Filtration Rates and Scaling in Demosponges Journal of Marine Science and Engineering allometric scaling sponge module choanocyte density specific filtration rate |
| title | Filtration Rates and Scaling in Demosponges |
| title_full | Filtration Rates and Scaling in Demosponges |
| title_fullStr | Filtration Rates and Scaling in Demosponges |
| title_full_unstemmed | Filtration Rates and Scaling in Demosponges |
| title_short | Filtration Rates and Scaling in Demosponges |
| title_sort | filtration rates and scaling in demosponges |
| topic | allometric scaling sponge module choanocyte density specific filtration rate |
| url | https://www.mdpi.com/2077-1312/10/5/643 |
| work_keys_str_mv | AT hansulrikriisgard filtrationratesandscalingindemosponges AT poulslarsen filtrationratesandscalingindemosponges |