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- Title
- Mechanisms of Coexistence Between Two Octopus Species In A South Florida Lagoon.
- Creator
- Bennice, Chelsea, Brooks, W. Randy, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Theoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat....
Show moreTheoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat. Specifically, I assessed (1) spatial distribution of octopus home or “den” space, (2) habitat association, (3) octopus abundance, (4) foraging activity periods, (5) diet, and (6) associated substrates and behaviors used during foraging events. Octopus den locations were marked by GPS to quantify spatial patterns of both species and their spatial relationship to each other. Habitat associations were measured by quantifying photoquadrats of den and surrounding habitats. For foraging activity periods, a video camera was placed near an octopus den for 24-h observation to determine when each octopus species leaves/returns from foraging. Underwater video recording was used to determine associated foraging substrates and behaviors for both species. Prey remains from octopus’ dens and video recordings indicating prey consumption were used to determine diets of the two octopus species. Video recordings from the 24-h camera and foraging behavior events also provided observations of intra- and interspecific interactions. Results revealed that the two species are interspersed throughout the shallow Florida lagoon and are both abundant during the spring months (March, April, May). Although both species are interspersed throughout the lagoon, their den and surrounding habitat association differed. O. vulgaris was associated with hard bottom and M. defilippi was associated with soft bottom, thus they may not compete strongly for habitats. Each species used different foraging strategies and different primary prey, which may also lessen competition and facilitate coexistence. O. vulgaris had peak foraging activity during night hours, foraged mostly on hard bottom and mainly consumed bivalves while M. defilippi had peak foraging activity during day hours, foraged mostly on soft bottom and mainly consumed crustaceans. Octopuses also had species-specific foraging behaviors, with O. vulgaris using parachute attack and M. defilippi using flounder swimming and tripod stance. Additional intra- and interspecific interactions were video recorded and included: fishes following octopuses, predation attempts, agonistic encounters, cannibalism, and tactile communication. This study identified ecological and behavioral components that may facilitate coexistence of these sympatric species, provided insight into cephalopod niches and ecology, and provided baseline conservation requirements for sand-dwelling cephalopods, both of which may be using this site as a mating and nursery habitat.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013185
- Subject Headings
- Octopuses, Sympatry (Biology), Coexistence of species, Lagoons--Florida
- Format
- Document (PDF)
- Title
- The role of chemical and visual cues by two Sargassum shrimps in locating and selecting habitats.
- Creator
- Jobe, Corrine F., Florida Atlantic University, Brooks, W. Randy, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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The Sargassum community is comprised of a unique and diverse assemblage of organisms. Habitat detection by two of the most common invertebrates, Latreutes fucorum and Leander tenuicornis , was investigated. Results of this study do not support that either L. fucorum or L. tenuicornis respond to chemical cues released by the Sargassum habitat in the absence of other information. Habitat selection of both shrimp species was examined as well. Both L. fucorum and L. tenuicornis selected live...
Show moreThe Sargassum community is comprised of a unique and diverse assemblage of organisms. Habitat detection by two of the most common invertebrates, Latreutes fucorum and Leander tenuicornis , was investigated. Results of this study do not support that either L. fucorum or L. tenuicornis respond to chemical cues released by the Sargassum habitat in the absence of other information. Habitat selection of both shrimp species was examined as well. Both L. fucorum and L. tenuicornis selected live Sargassum over artificial Sargassum . Moreover, L. fucorum selected Sargassum natans over Sargassum fluitans when only visual cues were available, whereas large-sized L. tenuicornis selected S. fluitans under the same conditions. Conversely, habitat selection trials combining both chemical and visual cues resulted in no preference between the two Sargassum species by either shrimp species. Additional ecological factors that possibly influence habitat location and selection are discussed as well as the importance of Sargassum in terms of pelagic fisheries management.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13381
- Subject Headings
- Habitat (Ecology), Sargassum, Marine chemical ecology, Animal behavior
- Format
- Document (PDF)
- Title
- The fate of copper in flooded south Florida agricultural soils and its toxicological effects on the Florida apple snail, Pomacea paludosa.
- Creator
- Rogevich, Emily Catherine, Florida Atlantic University, Brooks, W. Randy, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Agricultural sites have been acquired under the Comprehensive Everglades Restoration Plan (CERP) for the creation of water storage areas. Copper desorption and toxicity to the Florida apple snail (Pomacea paludosa) were investigated using soils from these sites. Copper concentrations in II soils ranged from 5 to 234 mg/kg Cu dw, and when flooded, resulted in overlying water Cu concentrations from 9 to 308 11g/L Cu. Juvenile apple snails exposed to three flooded soils had high mortality and...
Show moreAgricultural sites have been acquired under the Comprehensive Everglades Restoration Plan (CERP) for the creation of water storage areas. Copper desorption and toxicity to the Florida apple snail (Pomacea paludosa) were investigated using soils from these sites. Copper concentrations in II soils ranged from 5 to 234 mg/kg Cu dw, and when flooded, resulted in overlying water Cu concentrations from 9 to 308 11g/L Cu. Juvenile apple snails exposed to three flooded soils had high mortality and decreased growth within 9 to 16 days in two ofthe three soils examined. To assess Cu toxicity to the apple snail at various life stages and water quality parameters, 96 hour acute toxicity studies were conducted. Copper was more toxic to juvenile than adult apple snails. Copper toxicity increased as pH decreased and decreased as DOC increased. Hardness had no effect on Cu toxicity to the apple snail. Copper toxicity was a function of organism age, DOC and pH. Copper accumulation by juvenile and adult apple snails was determined for multiple exposure pathways. For 28 days, juvenile snails were exposed to aqueous Cu and adult snails were exposed to Cu contaminated soil, water and food. Whole body Cu in juvenile snails increased with time. The mean Cu bioconcentration factor (BCF) for juvenile snails was 1493. For adult snails, the dietary exposure pathway resulted in the highest bioaccumulation factor (BAF). Most Cu accumulated in soft tissue. During a chronic aqueous exposure, apple snails exposed to 8-16 flg /L Cu for 9 months had high Cu accumulation and significantly reduced clutch production (8-16 flg /L) and egg hatching (16 flg/L ). Chronic Cu exposure initially decreased growth in juvenile snails, but growth rebounded by adulthood and snails appeared to acclimate to chronic Cu exposure. When apple snails with high tissue Cu were fed to redear sunfish (Lepomis microlophus) Cu transfer was minimal, suggesting that the risk of trophic transfer (bioaccumulation) of Cu from the snail to redear sunfish is low and that biomagnification is unlikely. It is uncertain if other apple snail predators would be at risk for dietary Cu transfer.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00000875
- Subject Headings
- Soil pollution--Florida, Florida applesnail--Habitat, Florida applesnail--Effect of heavy metals on, Copper--Toxicology, Ecosystem management--Florida
- Format
- Document (PDF)
- Title
- The role of symbiotic dinoflagellates in the temperature-induced bleaching response of Aiptasia pallida.
- Creator
- Perez, Santiago F., Florida Atlantic University, Marsh, G. Alex, Cook, Clayton B., Brooks, W. Randy, Koch, Marguerite
- Abstract/Description
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Bleaching of reef corals and other cnidarians symbiotic with zooxanthellae can be attributed to the stress response of the host, algae or both. To determine if zooxanthellae are involved in the bleaching process, I infected a single strain of sea anemone, Aiptasia pallida with zooxanthellae from different hosts. I measured expulsion of the algae from the host during 24-hour incubations at 25, 32 and 34C, as well as photosynthetic rates at these temperatures. Photosynthesis and expulsion of...
Show moreBleaching of reef corals and other cnidarians symbiotic with zooxanthellae can be attributed to the stress response of the host, algae or both. To determine if zooxanthellae are involved in the bleaching process, I infected a single strain of sea anemone, Aiptasia pallida with zooxanthellae from different hosts. I measured expulsion of the algae from the host during 24-hour incubations at 25, 32 and 34C, as well as photosynthetic rates at these temperatures. Photosynthesis and expulsion of zooxanthellae were inversely and directly proportional to elevated temperatures, respectively. Photosynthesis and expulsion of zooxanthellae isolated from Condylactis gigantea showed the greatest sensitivity to elevated temperature when compared to other zooxanthellae tested. These results suggest that zooxanthellae have a function in the bleaching process and that this function may be related to their photosynthetic response. Thus, the differential tolerance of zooxanthellae to stress could partly explain the spatial variability characteristic of coral-bleaching episodes.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15698
- Subject Headings
- Dinoflagellates, Sea anemones, Coral reef ecology, Seawater--Thermal properties
- Format
- Document (PDF)
