T'? Florida Scientist QUARTERLY JOURNAL OF THE FLORIDA ACADEMY OF SCIENCES WALTER K. TAYLOR, Editor HENRY O. WHITTIER, Editor Volume 43 Spring 1980 No. 2 Biological Sciences BRYOZOAN-ALGAL ASSOCIATIONS IN COASTAL AND CONTINENTAL SHELF WATERS OF EASTERN FLORIDA JUDITH E. WINSTON (1) AND NATHANIEL J, EISEMAN (2) (I) Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218; (2) Harbor Branch Foundation, Inc., RR 1, Box 196, Ft. Pierce, Florida 33450 ABSTRACT; Sur?eys of Bnjozoa occurring on algal substrata were carried out in the shallow subtidal and deep (30-90 m) continental shelf waters of the Florida East Coast. Twenty-eight species of bryozoans were found on 12 species of algae in the shallow subtidal. Thirty-six species of bryozoans were found on 12 .species of algae at the continental .shelf stations. Membranipora tuberculata and Thalamoporella gothica floridana were the most common bryozoan species in the coastal collections, and Aetea sica andMicroporeUa cihata in the continental shelf collections. No bryozoans were found on noncalcified Chlorophyta, The calcified Chlorophyta and the m.ore massive species of Phaeophyta and Rhodophyta were the preferred substrata. * ASSOCIATIONS between bryozoans and algae have been noted since Dar- win (1845), Other early workers on these associations include Busk (1852), Joliet (1877), and Hincks (1880). More recent work (Ryland, 1959; Crisp and Williams, 1960; Ryland and Stebbing, 1971; Hayward, 1973; Hayward and Harvey, 1974) has increased our understanding of the ecological bases of these relationships (e.g., the role of the larvae in substratum selection). Only 3 studies have described ectoproct-algal associations in specific regions. Rogick and Croasdale (1949) described bryozoan species found on algae in localities ranging from New Hampshire to Buzzards Bay, collected from in- tertidal to 18 m depths. Ryiand (1962) has listed such associations for the coast of Wales in the intertidal and shallow subtidal zones. Pinter (1969) has discussed bryozoan-algal associations in intertidal habitats of southern California. No one has made a study of bryozoan-algal associations per se in warm ' The costs of publication of this article were defrayed in part b)' the- paytnent of charges from funds made available in support of the research which is the subject of this articio. In accordance with 18 U.S.C. ? 17,34, this article must therefore be hereb\' marked "advertisemcnl" soleK' to indicate this fact. 66 FLORIDA SCIENTIST [Vol. 43 water regions, although observations of the occurrence of particular species of bryozoans on algae is found in taxonomic works on these regions, e.g.. Maturo (1957) notes 14 species of Bryozoa occurring on algae in the Beaufort, N.C. region. We examine ectoproct-algal associations in a sub- tropical region, the Atlantic coast of Florida. Previous studies have concen- trated on intertidal habitats. We compare collections made from the inter- tidal and shallow subtidal waters with collections taken from deeper con- tinental shelf waters (30-90 m). METHODS?Algae and bryozoans were collected at 4 coastal localities along the Atlantic coast of Florida and at 8 stations on the East Florida Con- tinental Shelf (Fig. 1). The coastal collections were made in 1975 as part of a larger survey (Winston, in prep.) and were carried out opportunistically. Two collections (27-III-75, 24-1V-75), were made in the Indian River in a seagrass bed located on the north side of Sebastian Inlet (Station 1). Several species of algae grow as detached clumps tumbling among the seagrasses (Eiseman and Benz, 1975). Only Solieria te?era supported bryozoans. The other collections were made along the open coast. Six collections of drift Sargassum were made at 3 locations: North Beach, Fort Pierce (Station 2); Walton Rocks (Station 3) and Semin?le Shores (Station 4), Hutchinson Island (11-11-75, 24-VI-75, 25-VI-75, 4-V1I-75, 8-IX-75, 6-X-75). These locations are all stretches of sandy barrier beach where drift algae were abundant after several days of onshore wjnds. Both eupelagic and attached species were examined, grouped here as Sargassum spp. because of the dif- ficulties in determining the species of fragmentary plants. The attached species Sargassum filip?ndula and the pelagic S. natans and S. fluitans are most commonly encountered in this area. After a storm in late June one large collection containing many algal species was made just north of the North Beach breakwater in Fort Pierce. This sample consisted of attached algae washed loose from the subtidal beach-rock ledges (to 10 m) and sub- and in- tertidal rocks of the breakwater itself. Continental shelf algae and bryozoans were collected by lockout divers from the JOHNSON-SEA-LINK (JSL) submersibles in September and November, 1977. Locations of each station are shown in Fig. 1. JSL 1-442 (6 Sept.; 90 m; 15.6?C) and JSL 11-292 (18 Nov.; 89.7 m; 16.0?C) (Station 5) were on a large rocky mound east of St. Lucie Inlet, Martin County, Florida. The area is subject to upwelling and high turbidity (nepheloid layers). The temperatures at the time of sampling are typical for the station, but temperatures as high as 26.7?C and as low as 8?C have been recorded. Currents on the mound are usually less than 10 cm/sec, but slow shifting of water masses seems to be a common occurrence. At a nearby station water temperatures on one occasion changed 12?C in 9 hr (J. Reed, pers. comm.). Oculina coral with its associated community and hydroids, bryozoans and echinoids are the dominant invertebrates. Stations 6-10 (JSL 1-444; 7 Sept.; 71.5 m; 20.0?C; JSL L445; 7 Sept.; 49.4 m; 27,0?C; JSL 1-447; 8 Sept.; 42.4 m; 26.8?C; JSL 1-448; 8 Sept.; 58.0 No. 2, 1980] WINSTON AND EISEMAN ? BRYOZOANS AND ALGAE 67 m; 15.1?C; JSL 1-450; 9 Sept.; 27.3 m; 28.0?C) are east of Singer Island, Palm Beach County, Florida. These are in a rubble zone with very little bot- tom relief. Nepheloid layers have not been observed here, and upwelling is much less common than at the St. Lucie Inlet Stations. Prevailing temperatures are 22-28 ?C, but temperatures as low as 9?C have been recorded. Prevailing currents in this area are 20-45 cm/sec. Currents up to 165 cm/sec have been observed. Sponges, hydroids and bryozoans are the Fic. 1. The Indian River and Singer Island region of Florida, showing the locations of Sta- tions 1-10. Station 1, Sebastian Inlet; 2, North Beach, Ft. Fierce; 3, Walton Rocks; 4, Semin?le Shores; 5, St. Lucie Mound; 6-10 Singer Island, Transect. 68 FLORIDA SCIENTIST [Vol. 43 primary sessile invertebrates at these stations. Small amphipods, decapods and polychaetes are common among the fronds of the larger algae and in the crevices of the rubble. Algae and bryozoans from the coastal stations were examined while alive. Those from the continental shelf stations were preserved in 5% seawater-formalin and returned to the laboratory for subsequent study. Voucher specimens for the algae species are in the Harbor Branch Founda- tion Herbarium (HBFH). RESULTS AND DISCUSSION?The results of the coastal collections are in Table 1. Twenty-eight species of bryozoans were recorded from 12 species of algae; 2 species of cyclostomes, 6 ctenostomes and 20 cheilostomes. No bryo- TABLE L Coastal Bryozoans associated w th algae. PHAEOPHYTA RHODOPHYTA C. u -2 a-2 t ^ .2 ^ .s^ .2 5 Q. ? = ?Ir.l ?:.? " c ~ 5 ^ 5 ?;' .2 E^ ? oo S ^ K .^ ^ 2 a 'S. h: 2.? C2 ? -0 a 3 CYCLOSTOMATA Crista mid'a Tvbulipora lunata CTENOSTOMATA Amathia distans Bowerbankia sp, A Bowerbankia grac?K Bowerbankia imbr?cala Nolella stipata Zoobotryon verticillalwn CHEILOSTOMATA Aetea sica Beania hirtissima Beania intermedia Bugula sp, B, Bugula neritina Bugula minima Electra bellula Escharoides costifer Hippotkoa hyalina Lagenicella marginata Membranipora tuberculata Microporella ciliata Pasythea tulipifera Samgnyella lafontii Scrupocellaria regularis Synnolum aegypliacxim Thalamoporella jalcifera Thalamoporella gothica Vittalicella contei Walersipora subovoidea X X X X X X X X X- X X X X X X X X No. 2, 1980] WINSTON AND EISEMAN ?BRYOZOANS AND ALGAE 69 zoans were recorded on Chlorophyta. Fourteen bryozoan species occurred on 4 species of Phaeophyta and 20 bryozoan species were found on 8 species of Rhodophyta. The greatest number of bryozoan species were found on Solieria te?era (Rhodophyta) (12 bryozoan species) and Sargassum spp. (Phaeophyta) (12 bryozoan species). Four species of bryozoans were recorded from Laurencia sp. (Rhodophyta) and 3 each from Cryptonemia crenulata and Bryotham- nion seaforthii f. disticha (Rhodophyta). The most abundant bryozoan in the coastal collections was Mem- branipora tuberculata which was found on Sargassum spp. most commonly, but occurred on 3 other species of algae (1 Phaeophyta and 2 Rhodophyta). Thalamoporella gothica floridana was also abundant, occurring on 4 algal species (3 Rhodophyta, 1 Phaeophyta) and Beania intermedia was found on 3 species (2 Rhodophyta and 1 Phaeophyta). Table 2 lists the results of the continental shelf collections. Thirty-six species of bryozoans were recorded from 12 species of algae: 3 species of cyclostomes, 3 species of ctenostomes and 30 species of cheilostomes. Sixteen species of bryozoans occurred on 2 species of Phaeophyta and 30 species of Rhodophyta. The greatest number of bryozoan species was found on Rhodophyta. Eighteen species of bryozoans were found on Rhodymenia pseudopalmata and 12 species occurred on Petroglossum undulatum. The calcareous green alga Udotea flabellum supported 14 species. Of the bryozoans reported, Aetea sica and Microporella ciliata were both found on 6 species of algae. Mimosella verticillata and Escharoides costifer each occurred on 4 algal species. Table 3 gives the numbers of species of bryozoans recorded from algae in 4 different geographic areas: the New England Coast (Rogick and Croasdale, 1949), the coast of Wales (Ryland, 1962), the coast of southern California (Pinter, 1969) and the Atlantic coast of Florida (this paper). It is evident that algae do provide a substratum for a considerable number of bryozoan species. In temperate regions where intertidal and subtidal rocks are commonly covered by large algae this is not surprising. Rogick and Croasdale (1949) found 29 of the 84 ectoproct species known at the time from the Woods Hole area to occur on algae. Ryland (1959) notes that most of the bryozoan species found in the intertidal regions of the Rritish Isles are found on algae. In subtropical Florida waters, the intertidal algae are much smaller. However, the number of bryozoan species found on algal substrata is similar, though very few epiphytic Rryozoa are found in the in- tertidal zone. They occur on a few species of algae. Only this study records bryozoans associated with algae from Vv'ater deeper than 40 m. Thirty-six species were found on algae from deeper water (42-90 m), slightly more than in shallow water of the same region. When the species lists from the 2 collections are examined, however, (Tables 1 and 2) it can be seen that there is little similarity. Only 6 species of cheilostomes: 70 FLORIDA SCIENTIST [Vol. 43 Aetea sica, Escharoides costifer, Microporella ciliata, Scrupocellaria regularis, Synnotum aegyptiacum and Thalamoporella falcifera and 2 species of ctenostomes: Amathia distans and Nolella stipata occur in both collections. Thus, the total number of species for both deep and shallow waters off the Florida East Coast is relatively large (56 species). TABLE 2. Continental sheif Bryozoans associated with algae. PHAEO- CHLOROPHYTA PHYTA RHODOPHYTA a II l? -2 ^ 'XI, ~ il II C 5t 2 ?3 - S"? Il il 5^ D o "s