Giant kelp

At small spatial and temporal scales, genetic differentiation is largely controlled by constraints on gene flow, while genetic diversity across a species' distribution is shaped on longer temporal and spatial scales. We assess the hypothesis that oceanographic transport and other seascape features explain different scales of genetic structure of giant kelp, Macrocystis pyrifera. We followed a hierarchical approach to perform a microsatellite-based analysis of genetic differentiation in Macrocystis across its distribution in the Northeast Pacific. We used seascape genetic approaches to identify large-scale biogeographic population clusters and investigate if they could be explained by oceanographic transport and other environmental drivers. We then modeled population genetic differentiation within clusters as a function of oceanographic transport and other environmental factors. Five geographic clusters were identified: Alaska/Canada, Central California, continental Santa Barbara...

Populations of many species display spatially synchronous fluctuations in abundance. Synchrony is most commonly attributed to three processes: factors that influence recruitment (e.g., dispersal, early survival), large-scale environmental variability, and spatially autocorrelated trophic interactions. However it is often difficult to link population synchrony to a specific dominant process, particularly when multiple synchronizing forces are operating. We utilized a new satellite-based data set of giant kelp (Macrocystis pyrifera) canopy biomass to examine population synchrony in southern California kelp forests on spatial scales ranging from 50 m to 300 km and temporal scales ranging from 1 to 11 years. We examined the relationship between synchrony and distance for adult kelp populations, kelp recruits, sea urchin abundance (a major grazer of kelp), and environmental variables known to influence kelp population dynamics. Population synchrony in giant kelp decreased with distance between populations: an initial rapid exponential decrease between 50 m and 1.3 km was followed by a second, large-scale decrease between distances of 1.3 km and 172 km. The 50-m to 1.3-km spatial scale corresponded to the scales of synchrony in the abundance of sea urchins and young kelp recruits, suggesting that local drivers of predation and recruitment influence small-scale synchrony in kelp populations. The spatial correlation patterns of environmental variables, particularly wave height, were similar to the synchrony-distance relationship of kelp populations from 1.3 km to 172 km, suggesting that regional environmental variability, i.e., the Moran effect, was the dominant process affecting synchrony at larger spatial scales. This two-step pattern in the relationship between kelp biomass synchrony and distance was apparent in each of the 11 years of our study. Our results highlight the potential for synthesizing approaches from both landscape and population ecology in order to identify the multiple processes that generate synchrony in population dynamics.

Understanding how species are distributed in the environment is increasingly important for natural resource management, particularly for keystone and habitat – forming species, and those of conservation concern. Habitat suitability models are fundamental to developing this understanding; however their use in management continues to be limited due to often‐vague model objectives and inadequate evaluation methods. Along the Northeast Pacific coast, canopy kelps (Macrocystis pyrifera and Nereocystis luetkeana) provide biogenic habitat and considerable primary production to nearshore ecosystems. We investigated the distribution of these species by examining a series of increasingly complex habitat suitability models ranging from process‐based models based on species’ ecology to complex generalised additive models applied to purpose‐collected survey data. Seeking empirical limits to model complexity, we explored the relationship between model complexity and forecast skill, measured using...

From 2002-2012 giant kelp restoration was conducted in Orange County, CA including grazer removal and outplanting of kelp. This was a community based project with 287 volunteer divers trained and more than 5000 kids involved in growing the kelp in their classrooms.

Egg masses of the Patagonian squid Doryteuthis (Amerigo) gahi attached to giant kelp (Macrocystis pyrifera) in the Magellanic channels of the sub-Antarctic ecoregion in southern South America is documented for the first time. Of seven egg masses observed between 2008 and 2011, one was taken to the laboratory to be analysed and photographed. Comprising long transparent capsules containing eggs, the masses were strongly attached to the stipes of M. pyrifera. This macroalgae is a potentially important economic resource due to its multiple industrial uses; this study shows that it also serves an important ecological role as a spawning substrate for D. gahi.

With more frequent destructive storms kelp forests may become younger and less dense  Yearly climate variations affect the timing of Saccorhiza polyschides life history. Laminaria ochroleuca populations need over 2 years to fully recover from destruction. Lower latitude Laminaria hyperborea intertidal populations are not selfsustainable.

The responses of seaweed species to increased CO2 and lowered pH (Ocean Acidification: OA) depend on their carbon concentrating mechanisms (CCMs) and inorganic carbon (Ci) preferences. However, few studies have described these mechanisms in the early life stages of seaweeds or assessed the effects of OA and its interactions with other environmental drivers on their functionality and photophysiology. Our study evaluated the effects of pH, light (PAR), temperature, and their interactions on the Ci uptake strategies and photophysiology in the early stages of Macrocystis pyrifera. Gametophytes were cultivated under varying pH (7.80 and 8.20), light (20 and 50 μmol photons m−2s−1), and temperature (12 and 16 ◦C) conditions for 25 days. We assessed photophysiological responses and CCMs (in particular, the extracellular dehydration of HCO3 − to CO2 mediated by the enzyme carbonic anhydrase (CA) and direct HCO3− uptake via an anion exchange port). This study is the first to describe the Ci uptake strategies in gametophytes of M. pyrifera, demonstrating that their primary CCM is the extracellular conversion of HCO3 − to CO2 mediated by CA. Additionally, our results indicate that decreased pH can positively affect their photosynthetic efficiency and maximum quantum yield; however, this response is dependent on the light and temperature conditions.

The brown algae (Phaeophyceae) are a group of multicellular heterokonts that are ubiquitous in today's oceans. Large brown algae from multiple orders are the foundation to temperate coastal ecosystems globally, a role that extends into arctic and tropical regions, providing services indirectly through increased coastal productivity and habitat provisioning, and directly as a source of food and commercially important extracts. Recent multi-locus and genome-scale analyses have revolutionized our understanding of the brown algal phylogeny, providing a robust framework to test evolutionary hypotheses and interpret genomic variation across diverse brown algal lineages. Here, we review recent developments in our understanding of brown algal evolution based on modern advances in phylogenetics and functional genomics. We begin by summarizing modern phylogenetic hypotheses, illuminating the timescales over which the various brown algal orders diversified. We then discuss key insights on our understanding of brown algal life cycle variation and sexual reproduction systems derived from modern genomic techniques. We also review brown algal speciation mechanisms and the associated biogeographic patterns that have emerged globally. We conclude our review by discussing promising avenues for future research opened by genomic datasets, directions that are expected to reveal critical insights into brown algal evolution in past, present, and future oceans.

M. pyrifera juvenile sporophytes (5 mm) were obtained under controlled environmental conditions from sporophylls collected in Metri in southern Chile (41o48´S). Two experiments were conducted to determine the ability of regeneration of juvenile fronds of M. pyrifera sporophytes:

The effects that ultraviolet radiation (UVR, 280 to 400 nm) and photosynthetically active radiation (PAR, 400 to 700 nm) had on early life stages of Mastocarpus stellatus and Chondrus crispus were studied to determine if differences in UVR tolerance could influence their recruitment success on the upper eulittoral shores of Helgoland (North Sea). Photosynthesis, germination capacity, DNA damage and carpospore repair were measured after exposures to different time lengths and intensities of PAR + UV-A + UV-B, PAR + UV-A or PAR alone, and also after recovery in low white light. Germination and photosynthesis of the low light adapted carpospores of both species were inhibited as PAR was increased. Supplemental UV-A and UV-B had a small additional effect on the F v /F m of M. stellatus but this effect was more pronounced in C. crispus. However, photosynthesis of both species significantly recovered after 48 h. Carpospore viability in C. crispus was more sensitive than in M. stellatus to UVR, while a higher dose was needed to achieve 50% germination inhibition in M. stellatus. Furthermore, UV-B-induced DNA damage, measured as cyclobutane-pyrimidine dimers (CPDs), was less in M. stellatus spores, which also exhibited an efficient DNA repair mechanism compared with C. crispus. In contrast, growth and chlorophyll a contents in young gametophytes of both species were not affected by repeated UV exposures. Higher total carotenoid was measured in plants exposed to UVR, indicating a photoprotection role, because photosynthesis completely acclimated to UVR after 3 d. Furthermore, DNA damage was not detected on mature fronds of both species when exposed to the full solar spectrum. Therefore, the susceptibility of carpospores to UVR could influence species recruitment to the upper eulittoral zone.

With more frequent destructive storms kelp forests may become younger and less dense  Yearly climate variations affect the timing of Saccorhiza polyschides life history.  Laminaria ochroleuca populations need over 2 years to fully recover from destruction.  Lower latitude Laminaria hyperborea intertidal populations are not selfsustainable.

At small spatial and temporal scales, genetic differentiation is largely controlled by constraints on gene flow, while genetic diversity across a species' distribution is shaped on longer temporal and spatial scales. We assess the hypothesis that oceanographic transport and other seascape features explain different scales of genetic structure of giant kelp, Macrocystis pyrifera. We followed a hierarchical approach to perform a microsatellite-based analysis of genetic differentiation in Macrocystis across its distribution in the Northeast Pacific. We used seascape genetic approaches to identify large-scale biogeographic population clusters and investigate if they could be explained by oceanographic transport and other environmental drivers. We then modeled population genetic differentiation within clusters as a function of oceanographic transport and other environmental factors. Five geographic clusters were identified: Alaska/Canada, Central California, continental Santa Barbara...

Ocean currents are expected to be the predominant environmental factor influencing the dispersal of planktonic larvae or spores; yet, their characterization as predictors of marine connectivity has been hindered by a lack of understanding of how best to use oceanographic data. We used a high‐resolution oceanographic model output and Lagrangian particle simulations to derive oceanographic distances (hereafter called transport times) between sites studied for Macrocystis pyrifera genetic differentiation. We build upon the classical isolation‐by‐distance regression model by asking how much additional variability in genetic differentiation is explained when adding transport time as predictor. We explored the extent to which gene flow is dependent upon seasonal changes in ocean circulation. Because oceanographic transport between two sites is inherently asymmetric, we also compare the explanatory power of models using the minimum or the mean transport times. Finally, we compare the direc...

We report the isolation and characterization of 16 microsatellite loci to study the population genetics of the giant kelp, Macrocystis pyrifera. Markers were obtained by screening a genomic library enriched for microsatellite motifs. Of the 37 primer pairs defined, 16 amplified clean polymorphic microsatellites and are described. These loci identified a number of alleles ranging from three to forty (mean = 16.5, and gene diversity ranging from 0.469 to 0.930 (mean = 0.774). The isolation and characterization of these highly polymorphic markers will greatly benefit much needed studies on the molecular ecology of this important macroalga.

The effects that ultraviolet radiation (UVR, 280 to 400 nm) and photosynthetically active radiation (PAR, 400 to 700 nm) had on early life stages of Mastocarpus stellatus and Chondrus crispus were studied to determine if differences in UVR tolerance could influence their recruitment success on the upper eulittoral shores of Helgoland (North Sea). Photosynthesis, germination capacity, DNA damage and carpospore repair were measured after exposures to different time lengths and intensities of PAR + UV-A + UV-B, PAR + UV-A or PAR alone, and also after recovery in low white light. Germination and photosynthesis of the low light adapted carpospores of both species were inhibited as PAR was increased. Supplemental UV-A and UV-B had a small additional effect on the F v /F m of M. stellatus but this effect was more pronounced in C. crispus. However, photosynthesis of both species significantly recovered after 48 h. Carpospore viability in C. crispus was more sensitive than in M. stellatus to UVR, while a higher dose was needed to achieve 50% germination inhibition in M. stellatus. Furthermore, UV-B-induced DNA damage, measured as cyclobutane-pyrimidine dimers (CPDs), was less in M. stellatus spores, which also exhibited an efficient DNA repair mechanism compared with C. crispus. In contrast, growth and chlorophyll a contents in young gametophytes of both species were not affected by repeated UV exposures. Higher total carotenoid was measured in plants exposed to UVR, indicating a photoprotection role, because photosynthesis completely acclimated to UVR after 3 d. Furthermore, DNA damage was not detected on mature fronds of both species when exposed to the full solar spectrum. Therefore, the susceptibility of carpospores to UVR could influence species recruitment to the upper eulittoral zone.

The effects that ultraviolet radiation (UVR, 280 to 400 nm) and photosynthetically active radiation (PAR, 400 to 700 nm) had on early life stages of Mastocarpus stellatus and Chondrus crispus were studied to determine if differences in UVR tolerance could influence their recruitment success on the upper eulittoral shores of Helgoland (North Sea). Photosynthesis, germination capacity, DNA damage and carpospore repair were measured after exposures to different time lengths and intensities of PAR + UV-A + UV-B, PAR + UV-A or PAR alone, and also after recovery in low white light. Germination and photosynthesis of the low light adapted carpospores of both species were inhibited as PAR was increased. Supplemental UV-A and UV-B had a small additional effect on the F v /F m of M. stellatus but this effect was more pronounced in C. crispus. However, photosynthesis of both species significantly recovered after 48 h. Carpospore viability in C. crispus was more sensitive than in M. stellatus to UVR, while a higher dose was needed to achieve 50% germination inhibition in M. stellatus. Furthermore, UV-B-induced DNA damage, measured as cyclobutane-pyrimidine dimers (CPDs), was less in M. stellatus spores, which also exhibited an efficient DNA repair mechanism compared with C. crispus. In contrast, growth and chlorophyll a contents in young gametophytes of both species were not affected by repeated UV exposures. Higher total carotenoid was measured in plants exposed to UVR, indicating a photoprotection role, because photosynthesis completely acclimated to UVR after 3 d. Furthermore, DNA damage was not detected on mature fronds of both species when exposed to the full solar spectrum. Therefore, the susceptibility of carpospores to UVR could influence species recruitment to the upper eulittoral zone.

Ocean currents are expected to be the predominant environmental factor influencing the dispersal of planktonic larvae or spores; yet, their characterization as predictors of marine connectivity has been hindered by a lack of understanding of how best to use oceanographic data. We used a high-resolution oceanographic model output and Lagrangian particle simulations to derive oceanographic distances (hereafter called transport times) between sites studied for Macrocystis pyrifera genetic differentiation. We build upon the classical isolation-by-distance regression model by asking how much additional variability in genetic differentiation is explained when adding transport time as predictor. We explored the extent to which gene flow is dependent upon seasonal changes in ocean circulation. Because oceanographic transport between two sites is inherently asymmetric, we also compare the explanatory power of models using the minimum or the mean transport times. Finally, we compare the direction of connectivity as estimated by the oceanographic model and genetic assignment tests. We show that the minimum transport time had higher explanatory power than the mean transport time, revealing the importance of considering asymmetry in ocean currents when modelling gene flow. Genetic assignment tests were much less effective in determining asymmetry in gene flow. Summer-derived transport times, in particular for the month of June, which had the strongest current speed, greatest asymmetry and highest spore production, resulted in the best-fit model explaining twice the variability in genetic differentiation relative to models that use geographic distance or habitat continuity. The best overall model also included habitat continuity and explained 65% of the variation in genetic differentiation among sites.

We report on additional occurrences of Red Abalone (Haliotis rufescens Swainson, 1822) that bring the total to seven from British Columbia coastal waters. Possible causes of the presence of Red Abalone include northward (winter) transport via kelp rafts from the Oregon-California area. We tested this hypothesis by performing DNA barcoding analyses on a fragment of kelp holdfast on the surface of one such shell establishing its identity as Nereocystis luetkeana (Mertens) Postels & Ruprecht - a giant kelp with a hollow stipe terminating in a bulbous pneumatocyst (gas-filled float). The occurrence of Red Abalone due to natural processes, besides being important biogeographically, has had important implications for indigenous peoples' pre- and post-contact trade and material culture.

Understanding how species are distributed in the environment is increasingly important for natural resource management, particularly for keystone and habitat forming species, and those of conservation concern. Habitat suitability models are fundamental to developing this understanding; however their use in management continues to be limited due to often-vague model objectives and inadequate evaluation methods. Along the Northeast Pacific coast, canopy kelps {Macrocystis pyrifera and Nereocystis luetkeana) provide biogenic habitat and considerable primary production to nearshore ecosystems. We investigated the distribution of these species by examining a series of increasingly complex habitat suitability models ranging from process-based models based on species' ecology to complex Generalised Additive Models applied to purpose-collected survey data. Seeking limits on model complexity, we explored the relationship between model complexity and forecast skill, measured using both cross-validation and independent data evaluation. Our analysis confirmed the importance of predictors used in models of coastal kelp distributions developed elsewhere {i.e., depth, bottom type, bottom slope, and exposure); it also identified additional important factors including salinity, and interactions between exposure and salinity, and slope and tidal energy. Comparative results showed that cross-validation can lead to over-fitting, while independent data evaluation clearly identified the appropriate model complexity for generating habitat forecasts. Our results also illustrate that, depending on the evaluation data, predictions from simpler models can outperform those from more complex models. Collectively, the insights from evaluating multiple We began with an HSI model using Depth, bottom type, Salt, and exposure, representing habitat suitability for canopy kelp as: decreasing non-linearly with Depth; increasing linearly with the probability of rocky reefs and salinity {within a defined range); and optimal across a range of exposures {Fig. 2). We used the three variants of bottom type {RF, RMSM, and BoP) to assess the sensitivity of the HSI models to this predictor. We assumed all factors contributed equally, and that all were essential {i.e., low on any factor led to low habitat suitability). We then examined the strength of association between each potential predictor variable and our survey data using univariate GLMs. We examined correlations between linear, quadratic, and cubic forms of all predictors with the presence-absence of each species {i.e., giant and bull kelp) as well as the combined canopy to inform how to best to generalise the observations {see Appendix 2 in Supplemental Material for details). We used the significant predictors from this univariate analysis in a structured variable selection approach to create four multivariate GLMs with increasing complexity. We began by defining a GLM to represent a parametric form of the HSI model, and a second using only the linear forms of the predictors identified as significant for the combined canopy kelp response variable. In the third model we increased model complexity by considering higher-order polynomial forms of the predictors. These polynomials always entered the models with all its terms. We used higher order polynomials to allow the GLMs to approach the complexity of GAMs and facilitate model comparison. Finally, for the fourth GLM, we considered interaction terms. At each step, the best model was selected using Akaike's Information Criterion {AIC), after considering both single term addition and single term removal. AIC also served as a stopping

We report the isolation and characterization of 16 microsatellite loci to study the population genetics of the giant kelp, Macrocystis pyrifera. Markers were obtained by screening a genomic library enriched for microsatellite motifs. Of the 37 primer pairs defined, 16 amplified clean polymorphic microsatellites and are described. These loci identified a number of alleles ranging from three to forty (mean = 16.5, and gene diversity ranging from 0.469 to 0.930 (mean = 0.774). The isolation and characterization of these highly polymorphic markers will greatly benefit much needed studies on the molecular ecology of this important macroalga.

Understanding how species are distributed in the environment is increasingly important for natural resource management, particularly for keystone and habitat forming species, and those of conservation concern. Habitat suitability models are fundamental to developing this understanding; however their use in management continues to be limited due to often-vague model objectives and inadequate evaluation methods. Along the Northeast Pacific coast, canopy kelps {Macrocystis pyrifera and Nereocystis luetkeana) provide biogenic habitat and considerable primary production to nearshore ecosystems. We investigated the distribution of these species by examining a series of increasingly complex habitat suitability models ranging from process-based models based on species' ecology to complex Generalised Additive Models applied to purpose-collected survey data. Seeking limits on model complexity, we explored the relationship between model complexity and forecast skill, measured using both cross-validation and independent data evaluation. Our analysis confirmed the importance of predictors used in models of coastal kelp distributions developed elsewhere {i.e., depth, bottom type, bottom slope, and exposure); it also identified additional important factors including salinity, and interactions between exposure and salinity, and slope and tidal energy. Comparative results showed that cross-validation can lead to over-fitting, while independent data evaluation clearly identified the appropriate model complexity for generating habitat forecasts. Our results also illustrate that, depending on the evaluation data, predictions from simpler models can outperform those from more complex models. Collectively, the insights from evaluating multiple We began with an HSI model using Depth, bottom type, Salt, and exposure, representing habitat suitability for canopy kelp as: decreasing non-linearly with Depth; increasing linearly with the probability of rocky reefs and salinity {within a defined range); and optimal across a range of exposures {Fig. 2). We used the three variants of bottom type {RF, RMSM, and BoP) to assess the sensitivity of the HSI models to this predictor. We assumed all factors contributed equally, and that all were essential {i.e., low on any factor led to low habitat suitability). We then examined the strength of association between each potential predictor variable and our survey data using univariate GLMs. We examined correlations between linear, quadratic, and cubic forms of all predictors with the presence-absence of each species {i.e., giant and bull kelp) as well as the combined canopy to inform how to best to generalise the observations {see Appendix 2 in Supplemental Material for details). We used the significant predictors from this univariate analysis in a structured variable selection approach to create four multivariate GLMs with increasing complexity. We began by defining a GLM to represent a parametric form of the HSI model, and a second using only the linear forms of the predictors identified as significant for the combined canopy kelp response variable. In the third model we increased model complexity by considering higher-order polynomial forms of the predictors. These polynomials always entered the models with all its terms. We used higher order polynomials to allow the GLMs to approach the complexity of GAMs and facilitate model comparison. Finally, for the fourth GLM, we considered interaction terms. At each step, the best model was selected using Akaike's Information Criterion {AIC), after considering both single term addition and single term removal. AIC also served as a stopping

Ocean currents are expected to be the predominant environmental factor influencing the dispersal of planktonic larvae or spores; yet, their characterization as predictors of marine connectivity has been hindered by a lack of understanding of how best to use oceanographic data. We used a high-resolution oceanographic model output and Lagrangian particle simulations to derive oceanographic distances (hereafter called transport times) between sites studied for Macrocystis pyrifera genetic differentiation. We build upon the classical isolation-by-distance regression model by asking how much additional variability in genetic differentiation is explained when adding transport time as predictor. We explored the extent to which gene flow is dependent upon seasonal changes in ocean circulation. Because oceanographic transport between two sites is inherently asymmetric, we also compare the explanatory power of models using the minimum or the mean transport times. Finally, we compare the direction of connectivity as estimated by the oceanographic model and genetic assignment tests. We show that the minimum transport time had higher explanatory power than the mean transport time, revealing the importance of considering asymmetry in ocean currents when modelling gene flow. Genetic assignment tests were much less effective in determining asymmetry in gene flow. Summer-derived transport times, in particular for the month of June, which had the strongest current speed, greatest asymmetry and highest spore production, resulted in the best-fit model explaining twice the variability in genetic differentiation relative to models that use geographic distance or habitat continuity. The best overall model also included habitat continuity and explained 65% of the variation in genetic differentiation among sites.

We report the isolation and characterization of 16 microsatellite loci to study the population genetics of the giant kelp, Macrocystis pyrifera. Markers were obtained by screening a genomic library enriched for microsatellite motifs. Of the 37 primer pairs defined, 16 amplified clean polymorphic microsatellites and are described. These loci identified a number of alleles ranging from three to forty (mean = 16.5, and gene diversity ranging from 0.469 to 0.930 (mean = 0.774). The isolation and characterization of these highly polymorphic markers will greatly benefit much needed studies on the molecular ecology of this important macroalga.

From 2002-2009 4 organizations worked on giant kelp restoration in the Southern California Bight.  The project involved growing kelp in classrooms with kids, outplanting it with trained volunteers and multitudes of surveys to determine our successes.

Author(s): Edwards, Matthew S. | Abstract: (1) The influence of ocean waves on giant kelp fronds results in the vertical transport of water along the thallus(2) Morphological traits of giant kelp result in vertical transport being greater than in the absence of giant kelp(3) Vertical flow along giant kelp thalli is persistent, but flow rate is correlated with vertical orbital displacements of the incident ocean waves

Niño-Southern Oscillations (ENSOs) were compared with regards to their strength and timing in the tropical Pacific Ocean, changes in ocean temperature and wave intensity, and their impacts to giant kelp populations in the Northeast Pacific. The Multivariate ENSO Index, oceanographic data, and kelp abundance data all show that the 1982-83 and 1997-98 ENSOs were stronger and resulted in greater losses of giant kelp than the 1986-87 and 1991-92 ENSOs, but that the 1982-83 and 1997-98 ENSOs differed with regard to the arrival of destructive waves relative to when the ocean waters warmed and cooled. The 1982-83 ENSO was more destructive to the giant kelp populations in central California, USA than the 1997-98 ENSO, but the 1997-98 ENSO was more destructive to the giant kelp in southern California. These events appeared similarly destructive to the populations in Baja California, Mexico. Recovery of the kelp populations also varied among the two strong ENSOs due to the ocean conditions following each ENSO. In southern and Baja California, recovery was slow following the 1982-83 ENSO, while recovery was more rapid following the 1997-98 ENSO. Unfortunately, the monitoring programs used to evaluate the kelp populations stopped shortly after the 1997-98 ENSO, resulting in a lack of data for comparisons with the more recent weak ENSOs that occurred between 2002 and 2010, or with the strong ENSO that occurred in 2014-2016. This supports the need for continued long-term monitoring programs to better understand how climate anomalies impact coastal ecosystems.

KURZFASSUNG: Komposition und Wachstum von .Parvosilvosa" aus dem untergetauchten Gezeitenbereich kalifornischer Tangw~ilder. AIs ,,Parvosilvosa" werden taxonomis& komplexe, rasenartige Pflanzenbest~inde bezeichnet, die aus kleinen Algen und mikroskopischen Entwicklungsstadien gr/Sf~erer Algen bestehen. Die vorliegende Untersuchung er/Srtert die 5kologische Bedeutung dieser Pflanzenkomponente als Teil der /Srtlichen Gesamtflora; sie basiert auf Schwimmtauch-Studien und Laboratoriumsexperimenten. Mit ,,Parvosilvosa" bedeckte Felsstlicke und Molluskenschalen wurden unter Laboratoriumsbedingungen natiirlichem und kiinstlichem Licht ausgesetzt. In den Kulturen konnten sowohl iuxurierende Formen yon bereits aus dem Biotop bekanntem Material als auch neue Formen festgestellt werden. Einige dieser Algen wuchsen sehr gut in Kultur und schritten zur sexuellen Fortpflanzung. Oftenbar existieren viele benthonische Algen zeitweise in Form yon Ruhestadien. Unrer giinstigen Bedingungen -wie sie beispielsweise in unseren Kulturen geboten werden -wachsen sie dann zu adulten Pflanzen heran. Die Erfassung des gesamten Algenbestandes eines Biotops d[irPce durch die hier angewandten Methoden erleichtert werden. Die durchgefiihrten Untersuchungen ergeben neue Ansatzpunkte fiir experimentelle Arbeiten im Litoral.

The large multicellular protist, Macrocystis pyrifera, or more commonly:: giant kelp, is a species of brown alga that is found along the Pacific west coast of North America from Central Baja California, Mexico to Central California, USA. The alga grows rapidly and contains a large amount of chlorophyll within its leaflike blades. Caitlin Sutton, et. alia, have previously shown in Chlorophyll in blades of giant kelp, Macrocystis pyrifera , at depths that light must travel down through M. pyrifera's upper canopy and impact the low stocks of the protist in order for the forests to remain alive and attached to the sea floor. This study was designed as further look into M. pyrifera as an attempt to determine if northern blades contain significantly more chlorophyll than southern blades taken within, and if so, could water temperature be seen to reflect this discrepancy. In order to study this, 45 sample vials from five regions along the California coast were analyzed. Every sample vial contained four 6.25 mm discs submerged in 5.0 ml of 80% acetone. Three sample vials from each blade were created for a total of nine sample vials from each of the five locations. The vials were incubated in ice water for a minimum of 75 hours. After incubating, the chlorophyll-acetone solutions were pipetted into cuvettes and analyzed using a Beckman DU 730 spectrophotometer. The analysis has shown that chlorophyll in the samples from blades collected in San Diego: 1.63 ± 0.0631 µg /L, Los Angeles: 1.02 ± 0.0990 µg /L, Santa Barbra: 1.64 ± 0.0873 µg /L, San Simeon: 4.30 ± 0.0984 µg /L, and Santa Cruz: 4.77 ± 0.123 µg /L held significant differences in chlorophyll between every site, except for San Diego vs Santa Barbara

During the ENSO event of 1997–1998, density and population structure were evaluated in a Macrocystis pyrifera forest located in Bahía Tortugas, Baja California, Mexico, near the southern limit of the species’ distribution in the Northern Hemisphere. Observations in Bahía Tortugas were made quarterly from January 1997 to September 1998 using SCUBA diving surveys. No macroscopic plants were found in the Bahía Tortugas area from October 1997 to April 1998, a local absence of at least 7 months. Aerial surveys further suggest regional disappearance along most of the Baja California coast during the event. Unexpectedly, plants were found in Bahía Tortugas again in July 1998, in spite of the widespread disappearance of the species less than a year earlier. Long-distance spore dispersal was an unlikely cause of the recruitment because: 1) the nearest spore source was more than 100 km away; 2) recruitment appeared to be simultaneous at many sites and occurred rapidly after the cessation of the ENSO event; and 3) the recruits occurred in the same areas as before disappearance. We suggest that a microscopic stage that was not visible during dive surveys survived the stressful conditions of ENSO and caused the recruitment event, supporting the hypothesis that a bank of microscopic forms can survive conditions stressful to macroscopic algae.

Following the 1982–83 El Niño, Macrocystis pyrifera (L.) C. Agardh, forests disappeared throughout their range in Baja California. The giant kelp forests subsequently recovered within this range except at their extreme southern limit, a region encompassing 50 km of coastline with a former giant kelp standing stock of 28,000 wet tons. Two techniques were tested to restore these forests: juvenile transplantation and seeding with sporophylls. For transplanting, juvenile M. pyrifera sporophytes were attached to Eisenia arborea stumps seasonally over a two-year period. Average survival of transplants ranged from 7% in spring to 41% in winter. After two years, the average number of basal fronds per plant increased from 2 to 64 per plant and surface fronds from 0 to 34 per plant. Average frond growth rate of the transplants ranged from 8.1 cm day−1 in summer to 10.8 cm day−1 in winter. No significant differences in growth rate were found among treatments (seasons) for the transplants, but control plants showed a seasonal variation, with higher frond growth rates in winter (13.3 cm day−1) and spring (9.3 cm day−1) and lower in summer (4.4 cm day−1). The seeding technique was tested in a fully orthogonal-block design with three factors with two levels (factors: ± sporophylls addition, ± Eisenia arborea and ± understory algae). Macrocystis pyrifera recruitment occurred only in treatments with added sporophylls. The highest recruitment occurred where all algae were removed from the bottom, followed by the treatments without understory algae but with Eisenia arborea. This results suggest that a lack of spores and the presence of understory algae were the main factors inhibiting Macrocystis pyrifera recruitment in the area. Lower sea water temperatures and high nutrient concentrations occurred in spring and high temperatures and low nutrients in summer suggesting, as in southern California, an inverse relationship between these two factors. The results suggest a combined approach of transplanting juveniles and seeding during spring would be most effective for restoring the M. pyrifera forests.