Gulf of Mexico Science

Volume 5 Number 1 Number 1 Article 1

10-1981

Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea () in the Northern Gulf of Mexico

Lionel Eleuterius Gulf Coast Research Laboratory

Harriet Perry Gulf Coast Research Laboratory

Charles Eleuterius Gulf Coast Research Laboratory

James Warren Gulf Coast Research Laboratory

John Caldwell Gulf Coast Research Laboratory

Follow this and additional works at: https://aquila.usm.edu/goms DOI: 10.18785/negs.0501.01

Recommended Citation Eleuterius, L., H. Perry, C. Eleuterius, J. Warren and J. Caldwell. 1981. Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea (trichodesmium) in the Northern Gulf of Mexico. Northeast Gulf Science 5 (1). Retrieved from https://aquila.usm.edu/goms/vol5/iss1/1

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf of Mexico Science by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. Eleuterius et al.: Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea Northeast Gulf Science Vol5, No.1, p. 1-11 October 1981

CAUSATIVE ANALYSIS ON A NEARSHORE BLOOM OF Oscillator/a erythraea (TRICHODESMIUM) IN THE NORTHERN GULF OF MEXICO

Lionel Eleuterius, Harriet Perry, Charles Eleuterius James Warren, and John Caldwell Gulf Coast Research Laboratory Springs, MS 39564

ABSTRACT: Physical, chemical, and biological characteristics which preceded and caused a bloom of Osclllatorla erythraea commonly known as trlchodesmlum In coastal waters of Mississippi and adjacent waters of the Gulf of Mexico are described. This Is the first report of the blue-green alga occurring in high density near the mainland and In a predominantly estuarine area of the northern Gulf of Mexico. Environmental conditions Immediately prior to and during the bloom were characterized by low rainfall, calm sea, a homogeneous water column, low nitrate-nitrogen (0-5 N03-N pg-atom/1), no measurable nitrite-nitrogen (0 N02-N pg-atom/ I), high water temperatures (29-30° C), high salinity (270/100), and a basic pH (8.3 to 8.4). Total phosphorus and orthophosphate& were also low prior to the bloom (0.1 P pg­ atom/1), but increased slightly during the later stages of the bloom (0.7 to 1.5 P pg-atom/ 1). The alga disappeared with the return of well-mixed sea water, lower salinity, lower temperature and acidic pH, and an increase in combined nitrogen content. Osclllatorla erythraea occurred in bundles of 10 to 25 trichomes or as a single filament, ranging from 8 to 15pm In diameter and about 0.3 mm in length. The alga occurred in patches with the greatest concentration near the surface. Some entrapment of zooplankton in the dense algal mass was observed, but most of the zooplankton was diverse and unharmed. Harmful effects of the on larger animals were not observed nor believed to have occurred.

' Blooms of the planktonf6,blue-green Antarctic waters. alga Oscillatoria erythraea (Ehrenberg) Experimental evidence indicates that Kutzing commonly known as tricho­ trichodesmium is capable of nitrogen desmium are common in tropical seas fixation (Dugdale et a/., 1961; Dugdale, around the world. This organism has et a/., 1964; Goering et a/., 1966; been reported frequently from the Indian Ramamurthy and Krishnamurthy, 1967; Ocean, especially the Bay of Bengal, the Carpenter, 1973; Taylor, et a/., 1973; Red and Arabian seas and the tropical Carpenter and McCarthy, 1975). Stewart Atlantic Ocean including the coastal and Bottomly (1976) review the literature waters of South America, the Sargasso and point out that many morphological Sea and the Strait of Florida (Moseley, types of blue-green algae show nitro- 1879; Brongersma-Sanders, 1957; 'genase activity. In some regions tricho­ Dugdale, eta/., 1961; Dugdaleeta/., 1964; desmium blooms become so intense and Sieburth and Conover, 1965; Goering, et widespread that they may make a major a/., 1966; Qasim, 1970; Yentsch, et a/., contribution to the nitrogen budget of the 1972; Carpenter, 1973). Blooms in the sea (Eppley and Thomas, 1969; Thomas, Pacific Ocean have been reported by 1971; Carpenter, 1973; Carpenter and Wood (1965) and Bowman and Lancaster Price, 1976). Trichodesmium may be de­ (1965).There are fewer reports of the alga trimental to certain plants and animals from temperate seas, indicating that (Bowman and Lancaster, 1965; Qasim, blooms occur less frequently northward 1970), while favoring the growth of others and southward from the tropics. Farran (Calef and Grive, 1966). Ramamurthy (1932) found trichodesmium off the (1970) reported no fish mortality in coast of Ireland and Wood (1965) reports dense concentrations of the alga, how­ it south of New Zealand and even in ever the diversity of fishes was decreased, Published by The Aquila Digital Community, 1981 1 1 Gulf of Mexico Science, Vol. 5 [1981], No. 1, Art. 1 2 L. Eleuterius, H. Perry, C. Eleuterius, J. Warren, and J. Caldwell

f· suggesting bloom avoidance by certain initiated on 13 August 1974, approximate­ . He also reported that 80 to 90% ly three days after initial reports of the of the gut content, of fish taken within the bloom, to determine its extent and in­ bloom, contained trichodesmium. tensity. Clarke-Bumpus samplers fitted There are no detailed reports on with 157 pm mesh nets were used for blooms of trichodesmium of temperate plankton collections at the surface and seas, especially nearshore, estuarine bottom. Tows were made at a constant areas. Thomas (1960) and Simmons and speed for intervals of ten minutes. The Thomas (1962) report trichodesmium tow interval for surface samples taken in from the eastern Mississippi Delta. the nearshore waters of Ship Island was Gunter et a/., 1948; Curl (1959); Humm three minutes, because of the great den­ and Caylor (1957); and Oppenheimer sity of the alga in the water column. Many (1970) report it from off the Florida, Mis­ samples were also taken from the surface sissippi and Texas coasts, respectively. and subsurface waters by bucket and Davis (1954) and Van Baalen and Brown subsamples made on a volume basis. (1969) report it from the Gulf of Mexico. Samples were preserved in the field in a Trichodesmium is known to the present 5% solution of formalin buffered with authors to be an ephemeral component of methenamine. the Mississippi Sound . Although hydrological data were However, some biological and ecological taken with each plankton sample, the characteristics of a large bloom of trich­ description of the physical conditions odesmium occurring in Mississippi occurring during the bloom is based on Sound and in the immediately adjacent unpublished data from a concurrent waters of the Gulf of Mexic.o during the oceanographic survey of Mississippi \ late summer of 1974 are evaluated and Sound described by Eleuterius (1976a,). analyzed here to determine the cause of Conductivity, temperature; pH and dis­ the bloom. solved oxygen were measured in situ by a Mississippi Sound is separated from Martek water quality analyzer with an ac­ the Gulf of Mexico by a chain of barrier curacy of± 0.5° C. Conductivity was later islands, which lie from 12.9 to 19.3 kilo­ converted to salinity in ppt by an empiri­ meters (8 to 12 miles) off the mainland cal relationship. Transparency was de­ shore. Four rivers discharge fresh water termined by Spectronic 20 Perkin-Elmer into Mississippi Sound from the north and Spectrophotometer set at a wavelength of sea water enters Mississippi Sound 580 nanometers (nm). Distilled water was through the island passes; thus the water used as a standard and the instrument generally exhibits an increasing salinity adjusted to 100%. A sample of seawater g.~~c;l.ient from the mainland toward the was read as a percentage of light trans­ sea.~.Additionally, Mississippi Sound is mitted. Concentrations of the inorganic influenced by freshwater discharge from nitrogenous compounds, nitrate, nitrite Mobile Bay on the east and occasionally, and ammonium, were determined from during flood years, by the Bonnet Carre unfiltered seawater using standard sea Spillway of the Mississippi River on the water methods (Strickland and Parsons, west. 1972). Total phosphorus and orthophos­ phate of unfiltered seawater were deter­ METHODS AND MATERIALS mined using methods 11.3 and method 11.2.1 described by Strickland and Par­ Field procedure sons (1972), with no appreciable dif­ https://aquila.usm.edu/goms/vol5/iss1/1Surveys by boat and airplane were ferences found using filtered and unfilter- DOI: 10.18785/negs.0501.01 2 ------

Eleuterius et al.: Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea Estuarine Trichodesmium bloom 3

ed seawater samples. Regardless of the surface, and the air was permeated by a presence of phytoplankton or detritus in strong chlorine or iodine-like odor. Some the samples, for purposes of our analysis fishermen discribed the odor as that of it can only be regarded as an estimate or freshly-mowed grass or fresh tea. The approximation and not an absolute value scum formed great rafts on the water of the total nutrient budget of the sea­ surface and patches of dark brown or water. Sample analyses were carried out reddish water without rafts on the surface consistently and are the only chemical were easily delineated by aerial flights on data available which correspond to the 16 August. development of the bloom. Algal samples The sea was very calm during the were taken near Horn and Ship Islands by week prior to the bloom, the sunshine Gulf Coast Research Laboratory staff brilliant, and a gentle breeze prevailed. personnel and biologists of the Gulf Is­ These environmental conditions ac­ lands National Seashore, U.S. Park companied the bloom for about a week Service. after the onset, the bloom probably reaching peak development on the fourth Laboratory procedure or fifth day after it was first observed. Fresh samples were used to determine Heavy rain occurred on 20 August and the the concentration of the alga. Preserved alga disappeared for several days, then · plankton samples were stored in sea­ reappeared in low concentrations near water formalin (1 0%) for reference. the barrier islands for about another Algal trichomes were counted in milli­ week. liter aliquots using a Sedgwick-Rafter counting chamber. Repr~sentative Morphological characteristics of the alga samples of the freshly collected and The alga was found as single preserved alga were examined for trichomes or filaments and in bundles or morphological variation. fascicles just visible to the unaided eye. Algal samples taken during calm sea RESULTS AND DISCUSSION conditions (early period of the study, 10- 14 Aug) were in bundles, while those Period of occurrence taken later under rough seas were The senior author first observed the generally in single filaments. Rama­ algal trichomes as glittering slivers in murthy (1972) reported that the bundles the shallow waters near Horn Island on 5 .. disperse in rough seas. The filaments of August 1974. On 10 August 1974, reports >,the alga were 8 to 15 Jlm in diameter, and were received from local fishermen of about 0.3 mm in length. Some filaments amber-colored water in Mississippi were much shorter, indicating possible Sound, especially around the barrier breakage of the filament. Inconspicuous islands. Aerial reconnaissance on 12 filament sheaths were evident in some August showed that rafts of the alga were samples. The number of trichomes per forming in the waters north of the barrier fascicle ranged from 5 to 60 with an islands. Complaints that fishing was average of 15. Most fascicles contained poor accompanied these reports in local 10 to 25 trichomes. Sieburth and Conover newspapers and other news media. By (1965) reported 12 to 23 with an extreme 14 August the concentration of the alga of 80. had increased to the extent that the water Desikachary (1959) reported three was reddish, brown or gray; a thick (2.8 species from the Indian Ocean and em) scum was accumulating on the water McLeod,et a/. (1962) suggested that two Published by The Aquila Digital Community, 1981 3 Gulf of Mexico Science, Vol. 5 [1981], No. 1, Art. 1 4 L. Eleuterius, H. Perry, C. Eleuterius, J. Warren, and J. Caldwell

or more species may have been present in clumps could be easily seen in the their collection at Bermuda, based on shallow depths as glittering threads as taxonomic work by Sournia (1968). We their surfaces reflected light, giving the note, however, that the description~ of appearance of numerous small "hairs," the species presented by the authors commonly known as "sea sawdust." The above were based primarily upon the bloom paralleled the Mississippi coast morphology of the terminal ends of the for about 50 miles and extended less than trichomes which fall within the variability a mile beyond the barrier islands into the. of the specimens observed in our study. Gulf of Mexico, covering an area of Our description and identification of the several hundred square miles. Very low alga conforms with the revision of the concentrations of trichodesmium oc­ Osci/latoria by Drouet (1968). Use of the curred in the Gulf near the Chandeleur obsolete generic name as a common Islands. Housely (1976) stated that the name in the present study is based on its bloom extended into Alabama waters but frequent use in the past, and the present the entent of distribution was not deter­ familiarity associated with the name. mined. However, aerial flights indicated that the bloom did not reach as far east Bloom characteristics and distribution as Dauphin Island. The scum was com­ Trichodesmium occurred in patches posed of large masses of dead and living from 20-300 meters to over 2 kilometers in trichodesmium trapped in sea foam. diameter. A continuous band of great Large windrows of scum stained the concentration (over 105-1), 3 kilometers in sandy northern beaches of the barrier is­ width, occurred north of the barrier is­ land and vast areas of water were virtually lands (Figure 1). The algal cells and covered by the dark sand-colored algal \

Figure 1. General location of (Oscillatoria erythraea) trichodesmium bloom off the coast of Mississippi. The lightly shaded area delineates its location, with the heavily shaded area indicating the greatest con­ centration. The solid line indicates the track of the research vessel with circled numbers showing locations of stations established to determine the presence or absence of the alga, while numbers in squares show https://aquila.usm.edu/goms/vol5/iss1/1stations where plankton tows were made. DOI: 10.18785/negs.0501.01 4 Eleuterius et al.: Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea Estuarine Trichodesmium bloom 5

layer. After a few days, the pigment tom, Coscinodiscus concinnus (Sieburth phycoerythrin (Shimura and Fujita, 1975) and Conover, 1965). Although this diatom released from the dead algal cells, stained was very abundant in our samples, the a wide swath on the sandy beaches on contribution to the surface slick is un­ the north side of the barrier islands an clear since C. concinnus is known, from intense purple. There was a distinct ab­ related work by two of the junior authors, sence of algal windrows on the southern to be common and abundant in Missis­ beaches of the islands. sippi Sound throughout the year. Fur­ Although Wyatt (1975) and Reynolds thermore, the pattern of phytoplankton and Walsby (1975) provide information productivity in Mississippi Sound ascer­ on possible responses of phytoplankton tained to date, generally follows that des­ blooms including patterns of develop­ cribed by Russell-Hunter (1970) and ment and movement by vertical and hori­ Williams (1972) for estuarine waters. The zontal displacement, all of our observa­ most abundant phytoplankton genera as­ tions indicate that the bloom occurred sociated with the trichodesmium bloom in situ in Mississippi Sound including studied here were the diatoms Coscino­ observation of filaments throughout the discus, Chaetoceros, Biddulphia, Nitz­ water column three weeks before the schia and Tha/assiothrix, and the dino­ appearance of the surface scum. We have flagellate Ceratium. Comparison of our no evidence that the bloom drifted into data with those of Thomas (1960), Sim­ Mississippi Sound. Furthermore, Perry, mons and Thomas (1962), and Housley et at. (1979) recently reported on the ap­ (1976) indicate that the phytoplankters parent in situ occurrence "of a red tide listed above, other than trichodesmium, bloom in Mississippi Sound cf~d Gunteret form a major component of phytoplank­ at. (1948) reported on the in .. situ occur­ ton under non-bloom conditions. We sur­ rence of red tide blooms along the Florida mise that trichodesmium had little ef­ coast. There is also ample evidence in the fect on other phytoplankters. literature on eutrophication in estuaries and on associated algal blooms, that in­ Animals associated with trichodesmium dicates typically marine planktonic organisms can and do cause blooms in Zooplankton species (32) comprised coastal waters. primarily of common larval forms, ap­ peared to be unaffected by the occur­ Other phytoplankton associated with rence of the bloom; however, some trichodesmium mortality occurred through entrapment Inhibitory interaction between blue­ by the dense mass of filaments near the green and other algal species have been surface of the water. The overall effect of suggested by Boyd (1973) and Vance entrapment on zooplankton populations (1965). Bell, et at. (1974) have suggested was probably negligible. that selective stimulation by extracellular Animals found entrapped were products may account for algal blooms, motile, indicating that no toxic, lethal ef­ but nutritive competition has generally fect of trichodesmium occurred. Zoo­ been considered the cause (Hulbert, plankton diversity was typical of summer 1970; Thomas, 1970; Carpenter and communities in Mississippi Sound (Perry Guillard, 1971; Lange, 1974). and Christmas, 1972). This contrasts with The surface slick associated with a previous report where Qasim (1970) trichodesmium has been previously as­ f.ound a sparse community of zooplank­ signed to the commonly associated dia- ton associated with a bloom of tricho- Published by The Aquila Digital Community, 1981 5 ------

6 L. Eleuterius, H. Perry, GulfC. Eleuterius, of Mexico J. Science, Warren, andVol. J.5 [1981],Caldwell No. 1, Art. 1

desmium in the Indian Ocean. In additi6n, however, clearly shows that during the we found no associated organism which July-August 1974 bloom period relatively appeared to be favored by the algal bloom little fresh water was discharged into such as that reported for the copepod, Mississippi Sound, accounting in part for Macrosetella gracilis, by Calef and Grice the high salinity of the near-shore sea (1966), and no evidence that the bloom water. caused any mortality of larger animals. Phorphorus as orthophosphate and Local reports by fishermen indicated total phosphorus, although not shown in that fish apparently avoided the bloom Figure 2, followed the same general pat­ and no dead fish or other animals were tern as that of nitrogen. Ketchum (1967) seen during the bloom, either in the and Abbott (1957) indicated that phos­ Gulf, estuary, or on adjacent beaches. phorus and nitrogen sources are im­ Statistical comparison of fisheries data portant factors affecting nutrient avail­ (Perry, et at., 1974) taken during the ability and phytoplankton concentrations bloom with that of prior and subsequent in -sea water. The pattern of nutrient flux sampling periods, showed that no dif­ determined for Mississippi Sound follows ferences in fish diversity and abundance that general pattern described for tem­ could be assigned to trichodesmium. perate estuaries by Pomeroy, et at., However, observations by the senior (1972) and Williams (1972) except for the author corroborate reports that larger environmental conditions surrounding fishes avoided the bloom, perhaps, be­ the bloom. In the present study bright cause of the algal organism, or physical sunlight and transparent water were im­ and chemical conditions associated with portant factors that initiated and sus­ the bloom. No large fish were seen in the tained the bloom. The reduced amount of bloom area or taken by n~t. but large suspended organic matter resulting from schools of small menhaden and very the low river discharge, calm seas, and small mullet were observed on two oc­ high salinity water contributed to water casions in the bloom near Petit Bois transparency. Jerlov (1955) described Island and near the east end of Horn Is­ similar factors affecting the transparency land . Few crabs were observed in the of waters in the Baltic Sea. Furthermore, shallow water north of the islands during Packard and Blasco (1973) found that the bloom, although in other years "egg" nitrogen was light dependent and Grant crabs are generally very abundant there and Turner (1969) also showed that during August. bright sunlight stimulated nitrate assimi­ lation in several species of algae. Vaccaro Environmental con~itions and Ryther (1960) also observed a rela­ Physical and chemical parameters tionship between phytoplankton and the for ten stations within Mississippi Sound distribution of nitrite in the sea, and Bates including the island passes of Dog Keys, (1976) in a related study showed that light Horn and Ship islands (see Figure 1) were and ammonia affected the nitrate uptake combined and plotted as monthly of two estuarine phytoplankton species. averages as shown in Figure 2. River These reports taken collectively, in view discharge, also shown in Figure 2, is in­ of our findings, indicate the phytoplank­ dicative of the rainfall pattern for the Mis­ ton composition and concentration are sissippi coastal plain during the study also related in a complex manner to period. Comparison of the river discharge nutrient availability, interference, bright pattern with salinity, temperature, oxy­ light and transparent water. In the present gen, transparency, pH and nitrate-N, study relatively high pH and moderate https://aquila.usm.edu/goms/vol5/iss1/1 DOI: 10.18785/negs.0501.01 6 Eleuterius et al.: Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea Estuarine Trichodesmium bloom 7

concentrations of dissolved oxygen were recorded. Water temperatures also reached their annual peak (30°C} in August and there was no wind. Water 15 transparency increased during July and • oo.ooo also reached the summer maximum dur­ ing August. Sournia (1968), Gessner (1970) and Carpenter and Price (1976) found that blooms of trichodesmium oc­

curred during calm and impoverished 8 30 conditions of tropical seas during per­ iods of bright sunlight.

CONCLUSIONS

~ IOO.Ol99.0 In the present study a reduction of ~ 98.0 ct 97.0 detritus was related to the reduced dis­ ~ 96.0 ~ 95.0.l.rl--,-----,-.,...--,--r--,.-,..---r---,---r----, charge of fresh water from the adjacent river systems. Freshwater discharge is -. £ >- often loaded with suspended solids. Con­ !:: .: sequently the intrusion of highly saline -' "' water into Mississippi Sound probably "' 0 caused flocculation of suspended 8.5 materials. These conditiohs, coupled I \ "- with calm seas, were probably the pri- 75 mary factors responsible for the highly 40 transparent sea water (Jerlov 1955, Jones --SURFACE and Willis 1956). Kiefer and Austin (1974) ;;: 3.0 ------BOTTOM c also found that great concentrations of ~' 20 ::>

0 algae affected light transmission in the z"' open sea, thus at great concentration, 1.0 trichodesmium may have affected its

own ability to reproduce, which probably 10 contributed to the demise of the bloom...... ,,... *' ...... ,., ... We found no single factor which --SURFACE could be shown to be the cause of the o~__,.-,..---r---,--,-~-=--~-~--~-~-~~T~TO~M~----, F M A M J A S 0 N bloom. For example during the following Figure 2. Environmental parameters for 1974. Water year (1975) there was no appreciable salinity, temperature, pH, nitrate, nitrogen and dis­ difference in oxygen concentration or solved oxygen are shown for comparison before, pattern. Dissolved oxygen is generally during and after the occurrence of the trichodes­ mium bloom. All plots represent monthly averages low in Mississippi Sound during most for ten stations (see Figure 1 ). River discharge data summers (June-September). Oxygen (Water Resources for Mississippi Water Years 1974, concentration was only slightly higher 1975. U.S. Geological Survey) are not absolute values, but are indicative of the rainfall pattern for at the outset of the bloom when com­ the Mississippi coastal plain. pared to that near the end. Although salinity was higher in October than dur­ environmental events were obviously dif­ ing the bloom, the average temperature ferent in comparison with those during for October was much lower and other the summer bloom (Figure 2). The aver- Published by The Aquila Digital Community, 1981 7 8 L. Eleuterius, H. Perry,Gulf C. Eleuterius, of Mexico J. Science, Warren, Vol.and 5J. [1981],Caldwell No. 1, Art. 1

age concentration of nitrogen was a.lso slightly lower during the fall than dunng LITERATURE CITED the bloom. The bloom appears to be caused by a combination of specific con­ Abbott, W. 1957. Unusual phosphorus ditions: high temperature, very high salin­ source for plankton algae. Ecology ity, very transparent water, a slightly 38:152. alkaline pH, low nutrient concentrations, Bates, S. 1976. Effects of light and am­ moderate oxygen concentrations, calm monium on nitrate uptake by two seas (no wind) and brilliant sunlight. This species of estuarine phytoplankton. combination of physicial and chemical Limnol. Oceanogr. 21 (2):212-218. conditions may be of frequent occurrence Bell, W.H., J.M. Land, and R. Mitchell. locally because we have observed 1974. Selective stimulation of marine trichodesmium blooms in Mississippi by algae extracellular pro­ Sound of relatively short duration (2-3 ducts. Limnol. Oceanogr. 19:833-839 weeks) in 1976, 1978 and 1980. Bowman, T.E. and L.J. Lancaster. 1965. A Our findings agree with some en­ bloom of the planktonic blue-green vironmental parameters as outlined by alga, Trichodesmium erthraeum, in . Sournia (1968), Gessner (1970) and the Tongs Islands. Limnol. Ocean­ Carpenter and Price (1976) and the ogr. 10:291-292. morphological features described by Boyd, C.E. 1973. Biotic interactions be­ Drouet (1968). Very low concentrations tween different species of algae. J. Weed Sci. 21 (1 ):32-37. of trichodesmium are probably present in Mississippi Sound at all times, and a Brongersma-Sanders, M. 1957. Mass mortality in the sea. In: J.W. Hedge­ certain sequence of ~nvironmental events probably favor the ra'pid growth of peth [ed.], Treatise on marine ecolo­ gy and paleoecology. Geol. Soc. Am. trichodesmium over other phytoplank­ Memoir 67(1):941-1010. ton species. Therefore, we conclude that Calef, G.W. and G.D. Grice. 1966. Re­ the trichodesmium bloom occurred in situ within Mississippi Sound and such lationship between the blue-green blooms occur under a special combina­ alga and tion of environmental conditions, the copepod Macrostella gracilis in whether in the ocean or a typically estua­ the plankton off northeastern South rine ·area. And the trichodesmium bloom America. Ecology 47(5}:855-856. appeared benign in its effect on other Carpenter, E.J. 1973. Nitrogen fixation marine organisms. by Oscillatoria (Trichodesmium) thiebautii in the southeastern Sargasso Sea. Deep-Sea Res. ACKNOWLEDGMENTS Oceangr. Abstr. 20(3):285-288. and R.R.L. Guillard. 1971. Intraspecific differences in nitrate We wish to thank Dr. Harold Humm. half-saturation consultants for three for verifying our identification of tricho- species of marine phytoplankton. . desmium. Further thanks are also due Ecology 52(1):183-185 . Drs. Gordon Gunter and Edward Car­ and J.J. McCarthy. 1975. penter, for their review and constructive Nitrogen fixation and uptake of com­ criticism of the early drafts of this manu­ bined nitrogenous nutrients by script. We thank Lucia O'Toole and He}en Oscillatoria ( Trichodesmium thie­ Gill for typing and proofreading the bautii) in the western Sargasso Sea. manuscript. https://aquila.usm.edu/goms/vol5/iss1/1 Limnol. Oceanogr. 20:389-401. DOI: 10.18785/negs.0501.01 8 Eleuterius et al.: Causative Analysis on a Nearshore Bloom of Oscillatoria erythraea Estuarine Trichodesmium bloom 9

----· and C.C. Price. 1976. Part 1, Vol 1, p. 363-406. Wiley­ Marine Oscillatoria ( Tricho­ lnterscience, New York. desmium): Explanation for aerobic Goering, J.J., R.C. Dugdale and D.W. nitrogen fixation without hetero­ Menzel. 1966. Estimates of in situ cysts. Science 191 (4322):1278-1280. rates of nitrogen uptake by Tricho­ Curl, H., Jr, 1959. The hydrography of the desmium sp. in the tropical Atlantic inshore northeastern Gulf of Mexico. Ocean. Limnol. Oceanogr. 11:614- Publ. lnst. Mar. Sci. Univ. Texas 620. 6:193-205. Grant, B.A. and I.M. Turner. 1969. Light Davis, C.C. 1954. Phytoplankton of the stimulated nitrate and nitrite assimi­ Gulf of Mexico. Fish. Bull. U.S. 89: lation in several species of algae. 163-169. Comp. Biochem. Physiol. 29:995- Desikachary, T.V. 1959. Cyanophyta. 1004. Academic Press, New York. 686 p. Gunter, G., R.H. Williams, C. C. Davis, and Drouet, F. 1968. Revision of the classifi­ F.G. Walton Smith. 1948. Catastrop­ cation of the . hic mass mortality of marine animals Monogr. 15, Acad. Nat. Sci., Phila­ and coincident phytoplankton bloom delphia. 330 p. on the west coast of Florida, Novem­ Dugdale, R.C., J.J. Goering and J.H. ber 1946 to August 1947. Ecological .. Ryther. 1964. High nitrogen fixation Monographs 18:309-324. rates in the Sargasso Sea and the Housley, H.L. 1976. Distribution, periodi­ Arabian Sea. Limnol. Oceanogr. 9(4): city and identification of the phyto­ 507-510. \ plankton in the Bay of St. Louis, Mis­ ____ D.W. Menzel and J\H. Ryther. sissippi and the northeastern Gulf of 1961. Nitrogen fixation in-the Sargas­ Mexico. Unpublished dissertation. so Sea. Deep-Sea Res. 7:298-300. University of Southern Mississippi. Eleuterius, C.K. 1976a. Temporal and Hulbert, E.M. 1970. Competition for spatial distribution of nutrients. nutrients by marine phytoplankton in Mississippi-Alabama Sea Grant Con­ oceanic, coastal and estuarine sortium MASGP-024:20P. regions. Ecology 51 (3):475-484. -----· 1976b. Mississippi Humm, H.J. and R.L. Caylor. 1957. The Sound: Salinity distribution and in­ summer marine flora of Mississippi dicated flow patterns. Mississippi­ Sound. Contr. Mar. Sci. 4(2):228-264. Alabama Sea Grant Consortium. ._Jerlov, N.G. 1955. Factors influencing the MASGP Project #CO-ST-76-023. transparency of the Baltic waters. 128 p. Medd. Oceanogr. lnst. Goeteb. 25 Eppley, R.W. and W.H. Thomas. 1969. 1-19. Comparison on half-saturation con­ Jones, D. and M.S. Wills. 1956. The at­ stants for growth and nitrate untake tenuation of light in sea and estuarine in marine phytoplankton. J. Phycol. water in relation to the concentra­ 5:375-379. tion of suspended solid matter. J. Farran, G.P. 1932. The occurrence of Mar. Bioi. Ass. U.K. 35:431-444. Trichodesmium thiebautii off the Ketchum, B.H. 1967. Phytoplankton coast of Ireland. Rapp. PV. Rein. nutrients in estuaries. P. 329-335. Cons. perm. int. Expls. Mer. 755: In: G.H. Lauff [ed.], Estuaries. Publ. 60-64. Am. Assoc. Adv. Sci. 83. Gessner, R. 1970. Temperature: plants. Kiefer, D.A. and R.W. Austin. 1974. The ln:O. Kinne [ed.], Marine ecology, effect of varying phytoplankton con- Published by The Aquila Digital Community, 1981 9 Gulf of Mexico Science, Vol. 5 [1981], No. 1, Art. 1 10 L. Eleuterius, H. Perry, C. Eleuterius, J. Warren, and J. Caldwell

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Vol. 1:257-273. Blooms, [ed. V.R. LoCiero]. Mass. Strickland, J.D.H. and T.R. Parsons. 1972. Sci. and Tech. Found. p.81-93. A manual of seawater analysis. 2nd Yentsch, C.M., C.S. Yentsch and J.P. ed. Bull. Fish. Res. Bd. Can. Perras. 1972. Alkaline phosphatase 167:310 p. activity in the tropical marine blue­ Taylor, B.F., C.C. Lee, and J.S. Bunt. green alga Oscillatoria erythraeum 1973. Nitrogen fixation associated ("Trichodesmium"). Limnol. with the marine blue-green alga Oceanogr. 17(5):772-774. Trichodesmium as measured with the acetylene-reduction technique. Arch. Mikrobiol. 88:205-212. Thomas, J.P. 1971. Release of dissolved organic matter from natural popula­ tions of marine phytoplankton. Marine Biology 11:311-323. Thomas, W.H. 1960. Phytoplankton pro­ duction in the Mississippi Delta. pp. 103-116. /n.·Recent Sediments Northwest Gulf of Mexico. Amer. Assoc. Petrol. Geol. 1970. On nitrogen defi­ ciency and Tropical Pacific phyto­ plankton: Photosynt~etic para­ meters in poor and 'rjch water. Limnol. Oceanogr.15:38o"-385. Vaccaro, R.F. and J.H. Ryther. 1960. Marine phytoplankton and distribu­ tion of nitrite in the sea. J. Cons., Cons, Int. Explor. Mer. 25:260-271. Van Baalen, C. and R.M. Brown, Jr. 1969. The ultrastructure of the blue-green alga, Trichodesmium erythraeum, with special reference to the cell wall, gas vacuoles, and cylindrical bodies. Arch. Microbial 69:79-91. Vance, B.D. 1965. Composition and suc­ cession of cyanophycean water blooms. J. Phycol. 1:81-86. Williams, R.B. 1972. Nutrient levels and phytoplankton productivity in the estuary. Proceed. Coastal Marsh and Estuary Management Symposium p. 59-89. Wood, E.J.F. 1965. Marine microbial ecology. Reinhold, New York. 243 p. Wyatt, T. 1975. The limitations of physical models for red tides. Proceedings 1st Conference on Toxic Dinoflagellate Published by The Aquila Digital Community, 1981 11