Ecology of Corals, Seagrass and Mangroves

Human wading in shallow coastal waters is a common activity that inherently involves trampling of the substrate. An experiment was conducted in Thalassia testudinum seagrass beds in Puerto Rico to determine how seagrass and associated mobile fauna respond to this anthropogenic disturbance. Three trampling intensities were applied to replicate seagrass beds throughout a 4 mo period. Seagrass biomass was inversely related to trampling intensity and duration. There was moderate recovery in the trampled areas 7 mo after the last trampling event. Intense levels of trampling resulted in decreased shrimp abundances, especially for Thor manningi. Fish abundances and composition of shrimp and fish assemblages did not change significantly after 4 mo of trampling. T. testudinum beds with softer substrates lost more seagrass biomass as a result of trampling than seagrass beds with firm substrates, suggesting that substrate firmness can modify disturbance effects. Educators and resource managers should limit trampling by large groups, or confine it to small areas with firm substrates, and researchers should be mindful of artifacts arising from trampling in and around sampling areas.

BACKGROUND OVERVIEW Status of Mangroves in Southeast Asia The current status in southeast Asia is one of decline. Mangroves in southeast Asia make up an estimated 35% of global mangrove vegetation [1]. Since 1996 Southeast Asia has suffered the second highest decline in mangrove extent globally (6%) From 46,491km in 1996 to 43,737km in 2016. Indonesia remains one of the most vital holdings of mangrove forests globally, with estimated 20% of all Mangroves. This increase in deforestation of Mangroves could be for a multitude of reason, such as increased demand for commodities and increasing levels of aquaculture [2, 3]. Along with Southeast Asia holding a very large amount of the worlds Mangroves as mentioned previously, it also has the most diverse group of Mangrove species which carry many positive effect [4].

Studies in mangrove ecosystem are often focused on biological or ecological criteria and interdependency between mangroves and people is normally neglected. The situation is similar in Tamil Nadu; India which has a coastline of about 950 km. One of the major mangrove forests in Tamil Nadu is situated in Pichavaram, Cuddalore district. The present study was carried out in the seventeen hamlets, which are directly or indirectly dependent on the Pichavaram mangrove wetlands for their livelihood and survival. These seventeen hamlets consist of over 2600 households many of whom derive their principal income from fishing and related activities. Individual surveys were carried out for 10% of the households in each of the selected hamlets. Semi-structured questionnaires were used for surveys to study the attitude and perception of the community on the conservation and importance of mangrove wetlands and resources. The study was conducted to assess the awareness, attitudes and views of people dependent on the mangrove ecosystem towards conservation issues and development options. It was observed that a large percentage of the sampled population showed a positive inclination towards conservation of the ecosystem and were well aware of their responsibility towards it.

Current MSc thesis focuses on the monitoring of seagrass P.oceanica along the northern coasts of Crete Island, Greece, and investigates the application of the remote sensing techniques for the seagrass mapping. This research was articulated in two parts, where the first one involves an ecological approach to the seagrass distribution in various regions around the globe and the experience of seagrass monitoring nowadays. The second part of this work has technical character and investigates the application of the remote sensing techniques towards seagrass mapping. It, furthermore, focuses on the optical properties of the P.oceanica and other seafloor cover types, and studies distinguishability of various seafloor cover types. Studies of the optical characteristics of separate seafloor cover types were made with purpose to clarify, whether their spectral properties change with varying environmental conditions. Special attention has been drawn on the role of environmental factors on the distribution of P.oceanica along the coasts of Crete, and in particular, how the optical properties of the seafloor cover types, i.e. spectral reflectance, are being changed under varying external conditions, e.g. water column, amount of suspended particles and sediments in the seawater, and water temperature. Fieldwork research sites were presented by separate locations on the northern coast of Crete region (Ligaria, Agia Pelagia, Xerocampos). The additional measurements of the reflectance spectra of the seawater with and without sediments have been made in aquarium tank in 2009 by means of Trios-RAMSES spectroradiometer. Parallel to the collection of spectra signatures, we captured the imagery for the seagrass mapping, which consists of the aerial images from the Google Earth website and the satellite Landsat TM and ETM+ scenes.

Pada saat muson tenggara perairan selatan Jawa, Bali dan Nusa Tenggara mengalami upwelling yang berpengaruh ke perairan selat Bali disebut sebagai in-direct upwelling. Pengaruh upwelling ini bisa dilihat dari perubahan parameter fisika, kimia dan biologi perairan seperti suhu, klorofil-a dan nutrien. Penelitian ini bertujuan untuk mengetahui pengaruh terjadinya upwelling terhadap distribusi suhu, klorofil-a dan nutrien terutama nitrat,
fosfat, dan silika di Selat Bali dari hasil observasi bulan Juni-September 2012. Lokasi penelitian di koordinat 8,4 LS – 8,85 LS dan 114,40 BT – 115,5 BT. Metode yang digunakan adalah observasi lapangan saat terjadinya upwelling. Pengukuran parameter suhu dan klorofil-a menggunakan Conductivity Temperature Depth (CTD). Sampel nutrien
diambil tiap layer kedalaman dari permukaan sampai 100 m dibagi menjadi 3 zona mewakili karaketristik perairan utara (Laut Bali), tengah (Selat Bali) dan selatan (Samudera Hindia). Hasil penelitian menunjukkan terjadi peningkatan konsentrasi nutrien yang terlihat dari peningkatan konsentrasi nitrat, fosfat, silikat dan klorofil-a serta penurunan suhu. Konsentrasi klorofil-a maksimum di kedalaman 20 m zona selatan yang berhubungan langsung dengan Samudera Hindia dan terjadi kenaikan massa air dingin dikedalaman 70 m serta peningkatan konsentrasi fosfat di kedalaman 60 m, hal ini memperkuat bahwa pada bulan Juni-September perairan selat Bali mendapatkan pengaruh upwelling kuat dari Samudera Hindia.
Kata kunci : in-direct upwelling, suhu, klorofil-a, nutrien

Seagrass beds have high primary productivity and contribute as a source of food for marine biota, the leaves used as a substrate for micro and macro bentik, and the canopy characteristic can dampen the current and the waves, so it is being as an ideal habitat to the community gastropods to live both on leaves and under of the seagrass vegetation. This research aims to know the gastropod community and seagrass vegetation association on the seagrass beds ecosystems in Osi Island of the Kotania Bay -West Seram, done during of June 2012. Observations of vegetation seagrass and gastropod communities using systematic sampling method with transek and quadrants aids. Result of research showing the density, diversity index and evenness index of gastropods community associated with segarass bed habit of high density, and dominan index of gastropoda with associated with seagrass of low density. The Correlation of Pearson test results showing a strength relationship positive between seagrass vegetation with gastropod communities, which the high density of the seagrass vegetation contributed to the high density of gastropod communities.

Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant–herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore–plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with greater reductions in plant abundance compared with invasive herbivores and invasive plants, native herbivores and invasive plants, native herbivores and mixed-nativeness plants, and native herbivores and native plants. By contrast, assemblages comprised of native herbivores and invasive plants were associated with lower reductions in plant abundance compared with both mixed-nativeness herbivores and native plants, and native herbivores and native plants. However, the effects of herbivore–plant nativeness on changes in plant abundance were reduced at high herbivore densities. Our mean reductions in aquatic plant abundance are greater than those reported in the literature for terrestrial plants, but lower than aquatic algae. Our findings highlight the need for a substantial shift in how biologists incorporate plant–herbivore interactions into theories of aquatic ecosystem structure and functioning. Currently, the failure to incorporate top-down effects continues to hinder our capacity to understand and manage the ecological dynamics of habitats that contain aquatic plants.

Este estudo visa, através da aplicação de técnicas de sensoriamento remoto, contribuir
para o desenvolvimento de um modelo de fato sustentável das atividades ecoturísticas
nas áreas de manguezal da região e conferir suporte para a elaboração de políticas
públicas para o setor.

Aquatic plants fulfil a wide range of ecological roles, and make a substantial contribution to the structure, function and service provision of aquatic ecosystems. Given their well-documented importance in aquatic ecosystems, research into aquatic plants continues to blossom. The 14th International Symposium on Aquatic Plants, held in Edinburgh in September 2015, brought together 120 delegates from 28 countries and six continents. This special issue of Hydrobiologia includes a select number of papers on aspects of aquatic plants, covering a wide range of species, systems and issues. In this paper, we present an overview of current trends and future directions in aquatic plant research in the early twenty first century. Our understanding of aquatic plant biology, the range of scientific issues being addressed and the range of techniques available to researchers have all arguably never been greater; however, substantial challenges exist to the conservation and management of both aquatic plants and the ecosystems in which they are found. The range of countries and continents represented by conference delegates and authors of papers in the special issue illustrates the global relevance of aquatic plant research in the early twenty first century but also the many challenges that this burgeoning scientific discipline must address.

Using throw trap sampling, we compared the decapod and stomatopod fauna of the grasscovered mud banks in five major subenvironments of Florida Bay and tested for zonation in these fauna across individual banks. Fauna was primarily Gulf-Carolinean, despite the presence of a rich Antillean community just outside the bay. The two subenvironments adjacent to open ocean had high species richness, but banks became increasingly depauperate toward the interior of the bay, with the innermost study site supporting a virtual monoculture of the grass shrimp Thor j/oridanus. Species richness was similar across bank tops and exposed and sheltered sides. For the majority of species and sites, the exposed sides had the lowest abundance of the three transects. We suggest that restricted circulation may limit larval recruitment to inner portions of the bay (particularly for those species whose adult populations within the bay frequently fell to virtually nil) and that physical parameters, especially salinity, partially mediate the community structure of organisms that do gain access to the bay's isolated areas.

Structural analysis of mangrove  forests was carried out in Turiaçu Bay during 1997 and 1998. The study area is influenced by brackish to saline waters with the occurrence of Rhizophora mangle, Avicennia germinans, Laguncularia racemosa and Conocarpus erectus. The other two red mangrove species R. racemosa and R. harrisonii occur mostly in freshwater and oligohaline environments and were not included in this paper. It was measured all mangrove trees over 2.5 cm of DBH (Diameter at Breast Height), inside 26 plots of 30 x 30 m, in the right side of the bay. The sample sites were arbitrarily selected considering 3 mangrove types: fringe, riverine and basin mangroves. The results show high structural variability. Mangrove species may be present in homogeneous, monospecific stands or in mixed stands of 2 or 3 species. Tree height ranged from 2 to 20 m and DBH from 3 to 35 cm with estimated basal area ranging from 1 to 50 m2 /ha. Estimated tree density ranged from 200 to 2,000 trees/ha. The best developed stands were found in well flushed areas fringing the bay or along river margins. The less developed mangroves were found to be the basin type, in dried, sandy soils, in poorly flushed areas. The correlations between structural parameters were positive for tree height x DBH (r= 0.88), tree height x basal area (r= 0.87), and negative to tree density x DBH (r= -0.71) and tree height x tree density (r= -0.60). The most abundant and best developed species is A. germinans, followed by R. mangle. L. racemosa is less abundant as well less developed in structure than the others, independent of its location in fringe, basin or riverine stands. The high structural variability sets the fragility of mangrove ecosystems in Turiaçu Bay and the necessity of adjusting management techniques to achieve sustainable development.

Keywords: mangrove structure, mangrove landscape, Amazonian coast, coastal ecosystems.

Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith stable carbon and oxygen isotopes, to investigate for the first time the degree to which multiple tropical juvenile habitats subsidize coral reef fish populations in the Indo Pacific (Tanzania). Otoliths of three reef fish species (Lethrinus harak, L. lentjan and Lutjanus fulviflamma) were collected in mangrove, seagrass and coral reef habitats and analyzed for stable isotope ratios in the juvenile and adult otolith zones. d 13 C signatures were significantly depleted in the juvenile compared to the adult zones, indicative of different habitat use through ontogeny. Maximum likelihood analysis identified that 82% of adult reef L. harak had resided in either mangrove (29%) or seagrass (53%) or reef (18%) habitats as juveniles. Of adult L. fulviflamma caught from offshore reefs, 99% had passed through mangroves habitats as juveniles. In contrast, L. lentjan adults originated predominantly from coral reefs (65-72%) as opposed to inshore vegetated habitats (28-35%). This study presents conclusive evidence for a nursery role of Indo-Pacific mangrove habitats for reef fish populations. It shows that intertidal habitats that are only temporarily available can form an important juvenile habitat for some species, and that reef fish populations are often replenished by multiple coastal habitats. Maintaining connectivity between inshore vegetated habitats and coral reefs, and conserving habitat mosaics rather than single nursery habitats, is a major priority for the sustainability of various Indo Pacific fish populations. Citation: Kimirei IA, Nagelkerken I, Mgaya YD, Huijbers CM (2013) The Mangrove Nursery Paradigm Revisited: Otolith Stable Isotopes Support Nursery-to-Reef Movements by Indo-Pacific Fishes. PLoS ONE 8(6): e66320.

The dis cov ery of shell mid dens around the Bay of Daun and Lake Siranda (Las Bela, Balochistan) shows that groups of pre his toric gath er ers set tled along the coasts of Las Bela at least since the last two cen tu ries of the 8 th mil len nium BP. The ra dio car bon dat ing of the Daun sites in di cates that the ex ploi ta tion of the man grove re sources was not con tin u ous, but took place mainly dur ing two dis tinct pe ri ods of the 7 th and 5 th mil len nia BP. The pres ence of Neo lithic shell mid dens along the north ern coasts of the Ara bian Sea re in forces the im pres sion that this part of the In dian Ocean was first set tled dur ing the Mid dle Ho lo cene when the sea level had sta bi lized. The ra dio car bon dates ob tained from ma rine and man grove shells from the Tharro and Makli Hills in Lower Sindh, sug gest that coastal sea far ing be gan al ready in this pe riod.

The similarity of δ13C and δ15N patterns in hairs of different individuals from the Tsavo East orphaned elephant herd indicates that a single hair represents the dietary preferences and behavior of the entire group. Multiple tail hairs from the same individual collected at different times allows a chronology to be established because of the overlap in isotope patterns in hair, and there is a very high correlation between hair from different individuals in the same group. Forward modeling using a three-component isotope turnover model for hair allows a precise estimate of diet of these elephants over a 2-year interval. Elephants from Tsavo East National Park in Kenya feed predominantly on C3 leaves, although they have a significant fraction of C4 grass in their diet for a short time at the beginning of the rainy season. The overall integrated diet for the elephants studied is between 10% and 15% C4 grass, although it reaches up to 60% for short intervals.Stable carbon isotope analyses of elephant tooth enamel show that the average integrated dietary preference of elephants in Tsavo National Park remained less than 25% grass between 1940 and the present.

Epibenthic fish comn~unities residing in seagrass beds on shallow (<0.5 m) mudbanks in Florida Bay. USA, were quantitatively sampled with a throw trap method. The overall average density of 11 fish m-2 was substantially higher than most previously reported densities for seagrass habitats. Four sites, representing 4 different subenvironments of Florida Bay, differed widely in species composition and densities of individual species; results of discriminant function analysis indicated that fish communities at the 4 sites were relatively distinct. Species composition at different sites is proposed to be a result of complex interactions between the deterministic influence of habitat quality and the stochastic influence of larval availability. Restricted water circulation, effected by the network of banks, and different sources of water mass exchange are proposed as constraints on larval avdability. Differences in species richness and fish densities across individual banks corresponded to gradients in depth, sediment structure, detrital loads, and various measures of seagrass structural complexity. The greater physical stress on top of a bank appeared to limit species richness, while fish densities across in&vidual banks were regulated by habitat gradients. Multiple regression analysis indicated that the standing crop of seagrasses and the accumulation of vegetation litter were important determinants of fish densities; physical factors, such as depth and sediment structure, were also influential.

Seagrasses are marine angiosperms with a worldwide distribution that form conspicuous beds in near- shore habitats. Despite being universally recognised as a foundation species that performs a number of important ecosystems functions (incl. sediment stabilisation, facilita- tion of biodiversity, nutrient cycling and carbon sequestra- tion), global seagrass habitats are in decline. Resilience—the ability to recover from disturbance without switching to an alternative state—is paramount to the maintenance and persistence of seagrass habitats. Genetic diversity is a key component of seagrass resilience and contributes to an understanding of population structure, connectivity between populations, and reproductive strategies. Microsatellite primers were developed to investigate the resilience of the seagrass Zostera nigricaulis, which dominates subtidal habitats in the bays of south-eastern Australia. We also tested for cross-amplification of markers between Z. nigricaulis and previously developed markers for the sympatric species Z. muelleri to assess their applicability for use in assessing patterns of genetic diversity, population structure, and mat- ing system. Using next-generation sequencing we isolated 11 novel microsatellite loci for Z. nigricaulis, 8 of which were polymorphic for the samples tested. Allelic diversity ranged from 1 to 8. None of the primer pairs developed for Z. nig- ricaulis cross-amplified in Z. muelleri; but 14 of 24 primer pairs previously developed for Z. muelleri amplified clearly in Z. nigricaulis samples with six of these showing poly- morphism. The results demonstrate the applicability of the Z. nigricaulis microsatellite primers for use in the study of population genetics and limited cross-amplification with Z. muelleri.

NOTE 6 1 5~ evidence for nitrogen fixation associated with macroalgae from a seagrassmangrovecoral reef system ABSTRACT Early studies using acetylene reduction have vaux 1986) and are frequently covered by epiphytic suggested that macroalgae may contribute to nitrogen enrichblue-green algae such as Calothrjx sp, (Hi]lis-Colinment of waters near coral reefs via nitrogen fixation by their vaux 1980) that are capable of nitrogen fixation as indi-

Florida Bay is a shallow lagoonal estuary divided into basins by a latticework of mud banks, which exert a disproportionate influence on the bay ecosystem. Prevailing northeasterly winds resulted in distinct sheltered and exposed sides on narrow banks, the former with fine sediment and a high organic content and the high energy exposed sides with coarser sediment and low organic content. Bank water levels were highest in fall. Lunar tidal flux appeared to be directly related to the degree of access to open ocean for any given site. Water levels also demonstrated some degree of wind-dependency al all sites. Although water levels on narrow banks were highly correlated with those of basins, one 2-km-wide bank retained a lens of water at low tide despite lower levels in adjacent basins. Bank temperatures ranged from 7.5°C to 37 .O°Cand demonstrated a mean daily range of 4.5°C, but up to 15°C, in contrast to basin ranges of I_2°C. Temperature range was a function of air temperature range and water level. September through November was the most benign period on the banks. A bank in the northeastern bay was the physically severest of our six study sites. We discuss implications of the physical scenario for bank organisms; in general, banks should represent a more stressful habitat than deeper grassbeds.

From aerial photography (July 1987) and diving surveys (February 1988), 876 ha of seagrasses (eight species) were mapped in Cairns Harbour, tropical north-eastern Queensland. Zostera capricorni was the most common seagrass species and had the greatest biomass at 79 g m-2 dry weight of stems and leaves and 180 g mF2 dry weight of roots and rhizomes. The maximum shoot density found was 4798 shoots m-2 of Halodule pinifolia, the second most common species. Seagrasses were found only between 0.5 and 5.0 m below mean sea level. Zostera capricorni was found at the shallowest depths, Halodulepinifolia at the deepest depths. Twenty species of penaeid prawns, nine of which are marketed commercially, were sampled from the seagrass beds. Abundances of prawns of commercial species were significantly greater on seagrass-covered substrata than on nonvegetated substrata. Overall, 5614 mostly small or juvenile fish, representing 134 taxa, were sampled from seagrasses in Cairns Harbour. The most numerous fish species were a goby, Yongeichthys criniger, and a pony fish, Leiognathus splendens. Only 15 species were highly valued as recreational fish, and only 11 species were highly valued as commercial fish. Of the fish species, five (4%) were highly valued species of both groups. The density of fish on the seagrass beds was estimated to be 8809 fish ha-'.

Free-living colonies of Manicina areolata (Cnidaria: Scleractinia) inhabiting shallow, highenergy environments, are frequently overturned by waves and currents and are able to right themselves by a variety of adaptations. Coral colony complexity and size may influence the ability to right. We experimentally tested the relationship between various coral morphological attributes (e.g., area, meander density, and shape) and time required for righting. The average time for righting was 116 h (S.E. ± 28.7), with 86% of inverted colonies righting by the end of the 23 day experiment. Colony area was the only significant predictor of righting; large colonies were less efficient at righting. Effects of meander density and colony shape were minimal and were overwhelmed by the relatively strong influence of area. Although an increase in meander density may facilitate the process of sediment rejection in high energy environments it appears that the concomitant increase in area hinders the colony in terms of its ability to right.

The occurrence of major and minor chemical elements in the more common Baltic seaweed Oceanologta 2, 81-152 Bojanowski, R & Szefer, P (1979) Uranium in the Baltic water Studla t Matertalv Oceanologlczne 26, 253-274 (m Pohsh with Enghsh abstract) Cherry, R D & Shannon, L V (1974) The alpha radioactivity of marine organisms Atormc Energy Review, IAEA 12, 3-45 Edgmgton, D N, Gordon, S A, Thommes, M M & Almodovar L R (1970) The concentration of radium, thorium and uramum by tropical marine algae Limnol Oceanogr 15,945-955

Fishes inhabiting seagrass beds on shallow mudbanks in Florida Bay were sampled with throw traps, to capture the relatively sedentary, epibenthic species, and gillnets, to capture the more mobile species occupying the overlying water column. There was a strong heterogeneity in species composition and abundances of both components across different subenvironments ofthe Bay. The Interior section, characterized by a low tidal range and hypersaline conditions, harbored few epibenthic species relative to sites on the periphery of the Bay. Densities of Lucania parva, however, reached outstanding values, with a mean of 39 fish per m' at a West Interior site. Species richness of the water column component was also low in the Interior subenvironment, but a few species had high capture rates, despite salinities of up to 50 ppt. Three years of sampling in the northeast subenvironment indicated a trend from estuarine to marine conditions in salinity regime, seagrass growth, and densities of epibenthic fishes. A conceptual model was developed to aid in understanding the potential role of various biotic and abiotic factors in structuring fish communities on the banks. The distinctiveness of different subenvironments suggests that physical factors of water circulation and salinity patterns playa more influential role in Florida Bay than in more congruous seagrass ecosystems.

It has been argued that the "C-enrichment of benthic compared to pelagic consumers was a consebenthic compared to pelagic consumers is a functlon of diffel-quence of physical phenomena at low trophic levels, ential diffusion resistance In the boundary layer that surlow diffusion resistance in the boundary layer surrounds algae in these 2 environments. We pursued a field test and confirmed the hypothesis that differences in water planktonic algae cOndimotion may ulti~nately translate into differing 6°C values by tions versus higher diffusion resistance for benthic sampling benthic algae both i n s~d e and outside the flowalaae e x~o s e d to less water motion. Heckv & Hessleln U shielded habitats of seagrass beds and mangrove forcsts. (1995) elaborated on this hypothesis and, Macroalgae collected within seagrass beds were :'C:enriched relative to macroalgae at the edge or outside the the findings of Farquhar (1983), developed a theoretigrass canopy. However, the inverse held in the mangrove sys-cal model to predict carbon isotopic fractionation in tem where presumably photoasslmilation by sheltered relation to boundary layer thickness. Hecky & Hess-. . macroalgae of respiratory CO2 from the mineralization of leinfs (1995) model is supported by France's (1995a, b) mangrove detritus more than compensated for the effect of reduced water motion. Our findings suggest the application of compilations of worldwide F13C data on benthic and stable isotope analysis for the fine-scale study of foodweb planktonic studies demOnstratstructure on the b a s~s of local differences in water motion, but