Warm Shallow Waters Research Articles

A new pleurocystitid blastozoan from the Middle Devonian of the Eifel (Germany) and its phylogenetic importance

Rich echinoderm fauna from the Middle Devonian of the Eifel (Rhenish Massif, Germany) has yielded specimens of the rare recumbent pleurocystitid rhombiferans. Regulaecystis testudineus sp. nov. extends the stratigraphic range of the pleurocystitids to the Eifelian (Middle Devonian). Specimens show a strongly inflated and ornamented theca, which is unusual for the European pleurocystitids. Phylogenetic analysis of all described pleurocystitid genera suggests a close relationship of Regulaecystis with the other Devonian genera. Results indicate that the degree of inflation and of ornamentation of the theca can be interpreted as convergences within the pleurocystitids due to environmental conditions (such as surface consistency, hydrodynamism). R. testudineus sp. nov. was living as a strict epibenthic vagile organism; lying on muddy soft to firm substrates in quiet to agitated shallow warm water environments.

Geophysical Techniques for Low Enthalpy Geothermal Exploration in New Zealand

Shallow warm water resources associated with low enthalpy geothermal systems are often difficult to explore usinggeophysicaltechniques,mainlybecausethewarmwatercreatesaninsufficientphysicalchangefromthehostrockstobe easily detectable. In addition, often the system also has a limited or narrow size. However, appropriate use of geophysical techniques can still help the exploration and further investigation of low enthalpy geothermal resources. We present case studies on the use of geophysical techniques for shallow warm water explorations over a variety of settings in New Zealand (mostly in the North Island) with variable degrees of success. Asimpleanddirectmethodfortheexplorationofwarmwatersystemsisshallowtemperaturemeasurements.InsomeNew Zealand examples, measurements of near surface temperatures helped to trace the extent of deeper thermal water. ThegravitymethodwasutilisedasastructuraltechniquefortheexplorationofsomewarmwatersystemsinNewZealand. Ourcasestudiesshowthetechniquecanbeusefulinidentifyingbasementdepthsandtracingfaultsystemsassociatedwiththe occurrence of hot springs. Direct current (DC) ground resistivity measurements using a variety of electrode arrays have been the most common method for the exploration of low enthalpy geothermal resources in New Zealand. The technique can be used to detect the extentofshallowwarmwatersthataremoreelectricallyconductivethanthesurroundingcoldgroundwater.Groundresistivity investigationsusingtheelectromagnetic(EM)techniquesofaudiomagnetotellurics(AMTorshallowMT),controlledsource audio magnetotellurics (CSAMT) and transient electromagnetic (TEM) methods have also been used. Highly conductive clays of thermal or sedimentary origin often limit the penetration depth of the resistivity techniques and can create some interpretation difficulties. Interpretation of resistivity anomalies needs to be treated in a site specific manner.

Associazioni a Foraminiferi nel sistema di stagni costieri di Oliveri-Tindari (Sicilia nordorientale).

Foraminiferal assemblages in the coastal pools system from Oliveri-Tindari (North-eastern Sicily).Benthic foraminiferal assemblages from the Oliveri-Tindari lagoon (Messina, Italy), located on the Tyrrhenian coast of Sicily, have been studied.Results of grain size analyses showed that the silt fraction is predominant in almost all pools, except for the Marinello and Mergolo pools, whose sediment can be classified as silty clays.Optical microscopy examination revealed that size fractions higher than 63µm include both terrigenous and biogenic components (mostly Foraminifera).Based on micropaleontological study, the fauna consisted of 55 foraminiferal species belonging to 26 genera. The benthic foraminiferal assemblages included eurytherme and euryhaline taxa (Miliolids, Peneroplids and Ammonias), that are characteristic of sandy substratum and warm shallow waters or brackish environments. The foraminiferal assemblages also seemed to be diversified in relation to the grain-size.An estimation of the species diversity was performed using different parameters.Statistic diversity indexes showed that the two most ancient pools (Marinello and Mergolo) are considerably less rich in species than the other ones (Nuovo, Porto Vecchio, Fondo Porto, Verde). The observed stability of the foraminiferal assemblages confirmed they are reliable indicators of average environmental conditions of coastal ponds as highly dynamic environments, at least in the short-middle temporal scale.

Eutaleola, a replacement name for the homonym Euteleia (Bryozoa: Pasytheidae)

Eutaleola nom. nov. is proposed as a replacement name for Euteleia Marcus, 1938 (Bryozoa: Cheilostomata), a secondary homonym of Euteleia Raffray, 1904 (Arthropoda: Coleoptera). Eutaleola is a monospecific genus of Pasytheida e, found in warm shallow waters on both sides of the Atlantic and in deeper waters of the eastern Pacific. Brazilian material of Eutaleola evelinae (Marcus, 1938) comb. nov. is described and illustrated.

Distribuição temporal do ermitão Clibanarius vittatus (Anomura, Diogenidae) no litoral do Paraná

Um estudo sobre a flutuação temporal da estrutura populacional do ermitão Clibanarius vittatus (Bosc, 1802) foi realizado no Baixio Mirim, Baía de Guaratuba, Estado do Paraná, Brasil (25°52'S, 48°36'W). Clibanarius vittatus é uma espécie largamente estudada, entretanto estudos da biologia populacional desta em diferentes regiões são escassos. Coletas mensais foram realizadas na zona entremarés, de abril/2005 a março/2006. Foram obtidos 1187 ermitões, dos quais, 949 machos, 22 indivíduos intersexo, 204 fêmeas não ovígeras e 12 fêmeas ovígeras. O comprimento do escudo cefalotorácico (CEC) foi medido e agrupado em 10 classes de tamanho. Machos ocorreram em 10 classes de CEC, enquanto fêmeas e intersexos em apenas seis. A razão de sexos total e mensal foi a favor dos machos. Todas as categorias demográficas estiveram presentes o ano inteiro, com exceção dos intersexos e das fêmeas ovígeras. Estas foram pouco frequentes e ocorreram do final da primavera até o outono, e em agosto de 2005. O período reprodutivo foi considerado contínuo-sazonal, com maior intensidade nos meses mais quentes. A razão de sexos nesta população, que é diferente das demais estudadas, corrobora a teoria de migração proposta para esta espécie. O presente estudo constitui o primeiro registro do período reprodutivo desta espécie em águas rasas de clima subtropical quente.

Jamaican Taíno ‘Shellsmithing’ Techniques Explored: A Study in Method

Introduction Jamaica was inhabited by two separate groups of pre-Columbian people. The Ostionoid, or as James Lee called them, the Redware people arrived approximately A.D 650 ± 120^sup 2^, settling several known sites on the southwestern coast and on the central northern coast of the island as well. Then a later migration of Meillacan Ostionoid pottery-making people presumably from central Hispaniola arrived, approximately 1073 B.P^sup 3^ ± 95 or A.D 948 (Allsworth- Jones, 2008, p. 99). These were the Taino. They successfully settled most of the coastal areas of the island as well as many inland sites. Both cultures were technologically Ceramic Age peoples, who used the durable materials around them to fabricate and develop their material world, the hardwood trees, natural fibres, a large variety of stones, both igneous and sedimentary, and the shells collected primarily as food, which they used secondarily in their industrial and decorative arts. However, it is the indigenous use of shells and corals which fascinated me. Having been a practicing goldsmith, I understood the skill required in turning natural raw materials into naturally fabricated things of beauty, but pre-Columbian peoples were far superior in skill and ingenuity in their use of the seashell, compared to present-day manufacturers of shell craft items. From a careful study of certain worked artefacts (presented below) it appears that the Jamaican Tainos' understanding of the natural symmetry and internal structure of various gastropod shells (Figure 1) was advanced and equal to the skill of Mesoamerican (Mayan) craftsmanship (Scheie & Miller, 1 992, plates 27, 59, 85, 113, 121), or Aztec, or indeed the Classic Taino craftsmanship as seen on the other Greater Antillean islands of Hispaniola, Eastern Cuba and Puerto Rico (Bercht et al, 1998, plates 25, 26, 34, 85, 102). Though these cultures used Gastropod shells to make fantastic works of wearable art, their artisans relied on incision techniques and carvings on the surface of the shell to convey their ideas visually. The Jamaican Taino, however, seemed to prefer the use of the natural internal structure of the shells' columellas to translate and communicate ideas and imagery. Thus in my estimation their understanding of the shells' true decorative ability was far superior to the other previously named cultures. The most often used univalve shells were classified as the true conchs (Dance, 1992, pp. 57-64). The term 'conch' is used to designate a number of shell varieties, even those that do not belong to the true conch shell gastropod family as do the Strombus gigas (Queen conch), the Strombus gallus (Rooster Tail conch), Strombus raninus (Hawk Wing conch) and the Strombus pugilis (West Indian Fighting conch), which are common Caribbean varieties of the sea snails. Living in warm shallow waters, feeding on eel grasses and scavenging through coral sands, they often move into deeper waters as they reach the end of their reproductive maturity, although never to depths of more than 70 feet. At this depth their shells, which consist primarily of calcium carbonate bonded by a protein called conchiolin, start to thicken and lose their customary rippled appearance, as in the case of the Queen conch (Strombus gigas). This rippling can be found on the larger outer lip or flare of the Strombus gigas shell (Figure 2). However as this shell ages the rippled surface starts to attain a flattened appearance. In some cases this flattening is minimal and in others the flattening is complete, leaving a smooth sloping surface. The snail can live for 20 to 40 years. This longevity also influences the amount of horizontal rippling or ridges present on the body whorl, which continues to the outermost rim of the lip as well as to the thickness of the outer lip. The Melongena melongena or West Indian Crown conchs are also a variety of sea snail, and are not considered true members of the conch family though colloquially they are called by that name. …

Late Jurassic (Kimmeridgian) larger benthic Foraminifera from Santiago Coatepec, SE Puebla, Mexico

A micropaleontologic study was carried out from samples collected along a section that crops out in the Santiago Coatepec Stream, located in the southeast of the state of Puebla, Mexico. The sedimentary sequence begins with a reddish conglomerate. Above, thick and thin layers of grey-greenish sandstones that continue in fine-grained, calcareous sandstones, and, finally, in limestones. The reddish conglomerate may represent a continental environment, and the marine transgression began with the sandstone deposit that contains a marine association of Invertebrates such as Trigonids ( Myophorella sp.), and other Mollusks such as Trichites sp., Ostreids and Gastropods, Echinoderms, and Sponges as Cladocoropsis mirabilis. This sequence also provides a rich assemblage of larger Foraminifera as well as Algae, which is reported for the first time in this site. The larger agglutinated Foraminiferal assemblage is composed of Alveosepta jaccardi, Pseudocyclammina lituus, Everticyclammina virguliana, Rectocyclammina chouberti, Choffatella cf. Ch. tingitana, Mesoendothyra croatica, Nautiloculina oolithica, Freixialina planispiralis, Audienusina fourcadei, Placopsilina sp., Pseudocyclammina sp., Meandrospira sp. and Lenticulina sp. All those taxa were adapted to special paleoecological conditions, such as a continuous terrigenous input. The Algae are Marinella lugeoni, Pseudoepimastopora jurassica, Permocalculus sp., and Halimeda sp. The stratigraphic distribution of the larger benthic Foraminifera allow us to propose a Kimmeridgian age for the studied sequence. The opening of the Atlantic Ocean permitted the colonization of its margins by the larger Foraminifera during this time. The data provided by the larger Foraminifera, the Algae, and the lithology may suggest an internal platform environment of warm shallow water. This foraminiferal association is constituted by cosmopolitan species which are frequent in the Tethyan Realm.

Spectrogram denoising and automated extraction of the fundamental frequency variation of dolphin whistles

Marine mammal vocalizations are often analyzed using time-frequency representations (TFRs) which highlight their nonstationarities. One commonly used TFR is the spectrogram. The characteristic spectrogram time-frequency (TF) contours of marine mammal vocalizations play a significant role in whistle classification and individual or group identification. A major hurdle in the robust automated extraction of TF contours from spectrograms is underwater noise. An image-based algorithm has been developed for denoising and extraction of TF contours from noisy underwater recordings. An objective procedure for measuring the accuracy of extracted spectrogram contours is also proposed. This method is shown to perform well when dealing with the challenging problem of denoising broadband transients commonly encountered in warm shallow waters inhabited by snapping shrimp. Furthermore, it would also be useful with other types of broadband transient noise.

Middle and Late Jurassic roots of brachyuran crabs: Palaeoenvironmental distribution during their early evolution

Knowledge of early, Mesozoic crabs is still rudimentary, mainly due to the poor preservational potential of crustacean decapods. Fossil evidence suggests that the family Prosopidae is ancestral to all other brachyurans, including Podotremata, with a very close phylogenetic relationship to Homolodromiidae, Dromiidae, Homolidae, Latreillidae, Dynomenidae, Xanthidae, Cyclodorippoidea and Calappoidea. Prosopidae is an extinct family, consisting mostly of Mesozoic species, almost exclusively known by their carapaces. This family appeared in the late Early Jurassic (Late Pliensbachian) and disappeared at the end of the Danian. The Early Jurassic (Pliensbachian) oldest crab species, Eocarcinus praecursor Withers, is transitional in many of its observable traits between the macruran Glypheoidea (Middle Triassic Pseudopemphix) and the early brachyuran prosopids, especially the earliest known species, Eoprosopon klugi Förster (Late Pliensbachian). Middle Jurassic prosopids lived in shallow-sea, soft bottom environments. The oldest known prosopid species lived on a silty sea floor, as did the first known crab (late Early Pliensbachian), and their presumed ancestors (Pemphicidae) were probably also shallow water organisms. Middle Jurassic prosopids lived both in shallow warm waters within organic buildups/shelly accumulations, and on silty sea-floors during the Bajocian/Bathonian, as illustrated by a new example from central Poland. Prosopids had an evolutionary climax during the Late Jurassic and were widely distributed in sponge-microbial (Oxfordian) buildups and coral reef (Kimmeridgian–Tithonian) environments of Europe ( Pithonoton, Coelopus, Longodromites, Prosopon, Nodoprosopon, Lecythocaris, Glaessneropsis). When biohermal and reef facies retreated at the end of the Jurassic, favourable conditions for prosopid crabs diminished and Cretaceous prosopids are rare and spatially dispersed. Their closely related descendants, the homolodromiids, preferentially inhabited soft muddy bottoms in deeper, colder waters, as is well documented by Cenozoic and Recent occurrences.

A high-frequency warm shallow water acoustic communications channel model and measurements

Underwater acoustic communication is a core enabling technology with applications in ocean monitoring using remote sensors and autonomous underwater vehicles. One of the more challenging underwater acoustic communication channels is the medium-range very shallow warm-water channel, common in tropical coastal regions. This channel exhibits two key features-extensive time-varying multipath and high levels of non-Gaussian ambient noise due to snapping shrimp-both of which limit the performance of traditional communication techniques. A good understanding of the communications channel is key to the design of communication systems. It aids in the development of signal processing techniques as well as in the testing of the techniques via simulation. In this article, a physics-based channel model for the very shallow warm-water acoustic channel at high frequencies is developed, which are of interest to medium-range communication system developers. The model is based on ray acoustics and includes time-varying statistical effects as well as non-Gaussian ambient noise statistics observed during channel studies. The model is calibrated and its accuracy validated using measurements made at sea.

Faunal turnover and changing oceanography: Late Palaeozoic warm-to-cool water carbonates, Sverdrup Basin, Canadian Arctic Archipelago

Carbonate sedimentary rocks in the Fosheim–Hamilton sub-basin at the eastern end of the Sverdrup Basin contain a particularly sensitive record of changing palaeoceanography and faunal turnover during the northward movement of Pangaea through the Late Palaeozoic. Carboniferous and earliest Permian inner ramp carbonates are a photozoan association of colonial corals, fusulinids, algae and ooids, with sparse heterozoan elements (crinoids, brachiopods and bryozoans). Based on modern analogues these biotic components reflect warm-water oligotrophic marine environments. Contemporaneous mid-ramp and basin biotas are dominated by a heterozoan fauna (solitary corals, crinoids, bryozoans and brachiopods) that grew in cooler deeper waters that may have been beneath a thermocline. Initial cooling began in the latest Sakmarian with an influx of cool deep water and climatic deterioration allowing cool and warm waters to mix, disrupting the thermocline, and producing a sub-tropical marine biota whose remains were reworked by storms and re-deposited as tempestites. Faunas are heterozoan (crinoids, bryozoans, brachiopods and sponges) with photozoan elements (colonial corals and symbiont bearing fusulinids) prominent only in inner ramp facies. By late Artinskian these photozoan components are only present in shallowest basin-margin environments. Artinskian subtropical waters contained somewhat elevated trophic resources that together with mixing of photozoan and heterozoan elements in the subtropical inner ramp produced the greatest faunal diversity seen in the Sverdrup Basin. The biota was completely boreal in nature, and warm shallow waters with a warm refuge biota, were now supplemented by cool waters derived from the Panthalassa Ocean. Profound change took place in the Kungurian, coincident with localised uplift during the Melville Disturbance and increased siliciclastic input. Neritic, storm-dominated sediments are wholly heterozoan (brachiopods, bryozoans, crinoids and sponges) with no remaining photozoan elements. Nutrient levels are elevated (but not eutrophic) as indicated by phosphate and glauconite, extensive bioerosion, numerous infaunal foraminifers, and an impressive and diverse shelly biota, that during times of high siliciclastic input was replaced by a profuse Zoophycos infauna. Brachiopod and bryozoan faunas are distinctly boreal. Continued cooling, relatively high nutrients, as indicated by abundant glauconite and phosphate, and decreased siliciclastic input eventually resulted in an abundant heterozoan biota (brachiopods, bryozoans, crinoids and sponges) with local gigantism, but reduced brachiopod and bryozoan diversity. These Middle Permian rocks may be the coolest water deposits in the Sverdrup Basin. The faunas are still part of a boreal Arctic province, with strong ties to cool water faunas of Uralian basin. The succession ends with Late Permian biosiliceous spiculitic cherts containing accessory heterozoan components (brachiopods, bryozoans and few crinoids). These sediments, in part coeval with evaporites and terrestrial red beds on the Eastern European Platform, are interpreted to reflect a combination of cool waters, elevated nutrients, and mid-latitude storminess.

Coral growth bands: A new and easy to use paleothermometer in paleoenvironment analysis and paleoceanography (late Miocene, Greece)

Modern scleractinian corals are classical components of marine shallow warm water ecosystems. Their occurrence and diversity patterns in the geological record have been widely used to infer past climates and environmental conditions. Coral skeletal composition data reflecting the nature of the coral environment are often affected by diagenetic alteration. Ghost structures of annual growth rhythms are, however, often well preserved in the transformed skeleton. We show that these relicts represent a valuable source of information on growth conditions of fossil corals. Annual growth bands were measured in massive hemispherical Porites of late Miocene age from the island of Crete (Greece) that were found in patch reefs and level bottom associations of attached mixed clastic environments as well as isolated carbonate environments. The Miocene corals grew slowly, about 2–4 mm yr−1, compatible with present‐day Porites from high‐latitude reefs. Slow annual growth of the Miocene corals is in good agreement with the position of Crete at the margin of the Miocene reef belt. Within a given time slice, extension rates were lowest in level bottom environments and highest in attached inshore reef systems. Because sea surface temperatures (SSTs) can be expected to be uniform within a time slice, spatial variations in extension rates must reflect local variations in light levels (low in the level bottom communities) and nutrients (high in the attached reef systems). During the late Miocene (Tortonian–early Messinian), maximum linear extension rates remained remarkably constant within seven chronostratigraphic units, and if the relationship of SSTs and annual growth rates observed for modern massive Indo‐Pacific Porites spp. applies to the Neogene, minimum (winter) SSTs were 20°–21°C. Although our paleoclimatic record has a low resolution, it fits the trends revealed by global data sets. In the near future we expect this new and easy to use Porites thermometer to add important new information to our understanding of Neogene climate.

Optimal and Near-Optimal Signal Detection in Snapping Shrimp Dominated Ambient Noise

The optimal detection of signals requires detailed knowledge of the noise statistics. In many applications, the assumption of Gaussian noise allows the use of the linear correlator (LC), which is known to be optimal in these circumstances. However, the performance of the LC is poor in warm shallow waters where snapping shrimp noise dominates in the range 2-300 kHz. Since snapping shrimp noise consists of a large number of individual transients, its statistics are highly non-Gaussian. We show that the noise statistics can be described accurately by the symmetric alpha-stable family of probability distributions. Maximum-likelihood (ML) and locally optimal detectors based on the detailed knowledge of the noise probability distribution are shown to demonstrate enhanced performance. We also establish that the sign correlator, which is a nonparametric detector, performs better than the LC in snapping shrimp noise. Although the performance of the sign correlator is slightly inferior to that of the ML detector, it is very simple to implement and does not require detailed knowledge of the noise statistics. This makes it an attractive compromise between the simple LC and the complex ML detector

Coal Tailings Reclamation Practices: Soil Cover Variances - The Ayrshire Alternative

Reclamation of potentially acid producing coal processing waste generally requires 4 feet (1.2 m) of soil cover to comply with most state and federal requirements (Surface Mining Control and Reclamation Act of 1977 (PL 95 87)). Soil cover variances for acid coal slurry (tailings) have included alkaline amendments (agricultural limestone) and reduced soil cover depths. Direct seeding of alkaline amended coal tailings substrates has been demonstrated on more than 1,800 acres throughout the midwest since the late 1970's. Slurry reclamation practices have included upland cool season grasses and legumes, warm season native prairie grasses, and emergent and open water wetlands. Direct seeded slurry demonstrations implemented by the Cooperative Wildlife Research Laboratory SIUC during the 1980's and 1990's have received regulatory approval (bond release), as well as state and national (OSM) reclamation awards. Reclamation monitoring has documented vegetative cover, water quality, and substrate geochemistry through the period up to bond release. This annual monitoring has established a > 25-year database supporting the principles and practices of acid coal tailings reclamation. A recent soil cover variance at the Amax Ayrshire Mine (southwest Indiana) incorporated the principles of pyrite aging and weathering, and incremental limestone amendment to establish warm season grasses and shallow water wetlands on a ~170 acre (70 ha) acid producing slurry basin. Pre-treatment (1995) and posttreatment (1996 1999, 2003) substrate monitoring identified differential pyrite oxidation in unsaturated surface, and saturated subsurface profiles within the Ayrshire slurry basin. Agricultural limestone amendment (~100 150 tons/ac (225 335 Mg/ha)) has restored and maintained a favorable (alkaline) acid-base balance for seven years since the initial (1995) application. Warm season grass establishment provided > 87% aerial coverage in the direct seeded upland zones. Pretreatment acid (pH 2.6) surface water quality in the shallow wetland zone has been restored to post-treatment alkaline (pH 7.8) conditions. Additional

A recent sponge, Pleroma aotea Kelly ("Order” Lithistida: Family Pleromidae), in the late Eocene Ototara Limestone of Otago, New Zealand

Numerous remarkably well‐preserved lithistid sponges recovered from the late Eocene‐early Oligocene Ototara Limestone at Kakanui, North Otago, represent the first sponge body fossils to be described from the New Zealand Cainozoic. The sponges are scattered throughout a 1–3‐m‐thick volcaniclastic limestone horizon immediately overlying the Kakanui Mineral Breccia. The fossils are now solid calcite, the former siliceous skeleton having been replaced during diagenesis. The Kakanui sponges are the only known body fossils remaining from an extremely diverse sponge fauna which formed a major component of the benthos in the Kakanui‐Oamaru region in late Eocene‐early Oligocene times (c. 35–33 Ma). The sponge body fossils are described and compared with living sponges that have a similar flattened globose morphology. The fossils are morphologically indistinguishable from the living lithistid sponge Pleroma aotea Kelly ("Order” Lithistida: Family Pleromidae) from deep‐water seamounts and banks off north‐eastern New Zealand, and are significant in that they represent a stratigraphic range for the species of more than 35 million years. The present‐day distribution of P. aotea, limited to silica‐rich deeper waters, is in marked contrast to the relatively shallow warm water volcanic environments occupied during the Palaeogene. This restriction, and that of related lithistid sponges to silica‐rich deeper waters off northern New Zealand, is paralleled in other demosponges and several calcareous invertebrate groups such as barnacles, bryozoans, and crinoids.

The Geography of Evolutionary Opportunity: Hypothesis and Two Cases in Gastropods

Evolutionary innovations that require or provide increased per-capita energy budgets and competitive performance should appear at times and in places where resources are abundant and accessible and where predators and competitors impose intense selection. By contrast, innovations without functional benefits should become established in productive environments under conditions of weak selection from enemies. I confirmed these predictions in comparative studies of two types of innovation in gastropod shells. The labral tooth, a structure facilitating predation, appeared in 45 Cenozoic clades of marine gastropods, with the highest concentrations originating during the early Miocene, late Miocene, and Pliocene, all times and sites of high planktonic productivity, large expanses of warm shallow water, and diverse predator-rich biotas. Left-handed coiling, a condition with no obvious survival benefits, arose 19 times independently in right-handed clades. Most left-handed clades, including eight arising in regions outside the tropics, evolved in productive regions where the larva and/or the adult is shielded from intense predation. The times and places of origin of new traits in clades thus offer insights into the geography of evolutionary opportunity.

Biodiversity and Association of Dinoflagellates in Coral Reef Rubble, Carrie Bow Cay, Belize

AbstractThe species diversity and distribution of benthic dinoflagellates are illustrated from the back reef sand habitats at Carrie Bow Cay. Sand appears an ideal environment for nurturing a variety of species. Sand supported blooms of toxic, nontoxic, and parasitic assemblages of dinoflagellates. Morphology of dinoflagellates is illustrated in SEM and LM pictures; including the life cycle of a parasitic dinoflagellate's vegetative stage, sporogenetic stages, and the morphology of the feeding organelle. The feeding organelle of the primary dinoflagellate cysts is a hold fast and a peduncle‐like infestation tube, a ‘sucker organelle’, that inserts itself into copepod eggs. The parasitic dinoflagellate continues feeding on crustacean eggs since it is the only food source during vegetative cell division within the cyst. This is the first observation of the presence of parasitic dinoflagellates in shallow coral reef water. The study attempts to provide new knowledge on dinoflagellate associations and morphology of sand‐welling species in the microscopic food web of shallow warm tropical waters. Even, sand‐inhabiting invertebrates are not exempt from parasitic dinoflagellates.

Sedimentary phosphate formation in warm shallow waters: new insights into the palaeoceanography of the Permian Phosphoria Sea from analysis of phosphate oxygen isotopes

Abstract Oxygen isotopic analyses of the structural phosphate ( δ 18 O P ) in sedimentary phosphorites of the Upper Permian Phosphoria Formation reveal that phosphogenesis occurred across a broad range of palaeoenvironments. The δ 18 O P values from well-preserved hand-picked phosphate-grain separates range from 20.2 to 13.7 (±0.5)‰ SMOW, with the lowest values in the most landward shallow-water deposits and the highest values in the most basinward deeper water deposits. The relationship between the maximum burial depth and δ 18 O P is opposite to that predicted if burial diagenesis was responsible for the isotopic signature of these phosphate grains. This suggests that the regional trend in oxygen isotopic data is not due to burial diagenesis. The range in oxygen isotopic values does correspond to the potential range of palaeotemperatures in the shallow and broad epicontinental Phosphoria Sea. The range is 14–42°C (±3.5°C) assuming a seawater δ 18 O of −2.5 ‰ SMOW. Palaeotemperatures along an offshore to onshore transect indicate that upwelling involved temperate (14–26°C; mean of 21°C) but not cold waters, and that warming across the palaeoshelf resulted in mean shallow-water temperatures of 34–37°C. The latter values approximate those predicted by climate and ocean circulation models. These warm palaeotemperatures provide further evidence that phosphogenesis in the epicontinental Phosphoria Sea occurred under palaeoceanographic conditions that were different from modern phosphorite depositional systems. This suggests that a purely actualistic approach to the interpretation of the Phosphoria phosphorites is not valid.

The relationship between the thermohaline circulation and climate variability

The long-term integration with the Global Ocean-Atmosphere-Land System model of the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics(IAP), Chinese Academy of Sciences has been used in the investigations on the relationship between the thermohaline circulation and climate variability. The results show that the strength of the North Atlantic Thermohaline circulation (THC) is negatively correlated with the North Atlantic Oscillation (NAO). Based on this kind of relationship, and also the instrument- measured climate record such as air pressure and sea surface temperature, the activity of the thermohaline circulation during the 20th century has been evaluated. The inferred variations of the strength of the THC is that, during two multi-decadal periods of 1867 1903 and 1934 1972, the THC is estimated to have been running stronger, whereas during the two periods of 1904 1933 and 1973 1994, it appears to have been weaker. The climate system of the Earth can be broken down into a number of components: the ocean, the atmosphere, the lithosphere, the cryosphere, and the biosphere. The ultimate forcing mechanism of oceanic and atmospheric motions is the pole-to-equator gradient of radiative heating of the planet. There exists surplus of heat in the equatorial region and deficit of heat in the polar region. In order to keep the thermal balance of the Earth, the excessive heat collected in the equatorial regions must be transported to the polar regions. The transport is taken up by the meridional circulation branch of the climate system, which is mainly made up of the atmospheric components of the famous Hadley cell, the Ferrel cell, and the polar cell, and also its ocean component of the Atlantic thermohaline circulation. About 90% of the water in the world ocean are involved in the thermohalien circulation, which is located beneath the wind driven surface currents and at great depths. The power for this slower, deeper circulation comes from the action of gravity on adjacent water masses of different densities. Since density is largely a function of temperature and salinity, the circulation due to density difference is called thermohaline circulation. The contemporary thermohaline circulation is characterized as the Atlantic Great Ocean Conveyor Belt. Intense radiative cooling of the polar ocean surface during the winter causes the formation or extension of sea ice. Cooling and brine rejection (i.e. salt ejection during ice formation) produces an unstable density gradient in the upper ocean allowing the cool and saline dense water to mix down convectively. Just as the tropical ascent is the rising part of the atmospheric direct circulation (i.e. warm air rising), the sinking motion of the ocean is the thermally direct part of the ocean circulation (i.e. cold water sinking). The thermodynamically direct circulation converts potential energy into kinetic energy. These processes lead to the formation of the deep ocean water, which spreads out away from the poles until it slowly ascends toward the equator. At last, the water moves back to the poles from the equator in the form of shallow warm water circulation (1,2) .

Ambient noise imaging in warm shallow seas; second-order moment and model-based imaging algorithms

Ambient noise can be used to produce images of submerged objects using the mean intensity of the backscattered energy, a technique coined “acoustic daylight” because of its direct analogy to vision. It is suggested that there may be substantial additional information in higher moments of the data. At high frequencies (>10 kHz), absorption suppresses long-range propagation so that a received signal is largely dependent on the local geometry, source characteristics, and the scattering properties of interceding objects. It is shown that for snapping shrimp (Cragnon, Alpheus, and Synalpheus) illumination (the primary sources in warm shallow water above a few kHz), significant information is embodied in the second temporal moments of intensity. There is no visual analog to this concept, which suggests a broader imaging approach which may be termed ambient noise imaging (ANI). Another ANI technique explored is the use of spatial cross correlation, which works well and also has no visual analogy. A model-based processor (Kalman filter) is also applied to track targets subject to highly variable illumination such as provided by snapping shrimp. Examples are presented using data provided by Scripps Institution of Oceanography from the initial deployment of the Acoustic Daylight Ocean Noise Imaging System (ADONIS) in San Diego.